Solar variation

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One composite of solar variability between 1975 and 2005.

Solar variation is the change in the amount of radiation emitted by the Sun (see Solar radiation) and in its spectral distribution over years to millennia. These variations have periodic components, the main one being the approximately 11-year solar cycle (or sunspot cycle). The changes also have aperiodic fluctuations.^[1] In recent decades, solar activity has been measured by satellites, while before it was estimated using 'proxy' variables. Scientists studying climate change are interested in understanding the effects of variations in the total and spectral solar irradiance on Earth and its climate.

Variations in total solar irradiance were too small to detect with technology available before the satellite era, although the small fraction in ultra-violet light has recently been found to vary significantly more than previously thought over the course of a solar cycle.^[2] Total solar output is now measured to vary (over the last three 11-year sunspot cycles) by approximately 0.1%,^[3][4][5] or about 1.3 Watts per square meter (W/m²) peak-to-trough from solar maximum to solar minimum during the 11-year sunspot cycle. The amount of solar radiation received at the outer limits of Earth's atmosphere averages 1366 W/m².^[1][6][7] There are no direct measurements of the longer-term variation, and interpretations of proxy measures of variations differ. The intensity of solar radiation reaching Earth has been relatively constant through the last 2000 years, with variations estimated at around 0.1–0.2%.^[8][9][10] Solar variation, together with volcanic activity are hypothesized to have contributed to climate change, for example during the Maunder Minimum. Changes in solar brightness are considered to be too weak to explain recent climate change.^[11]

History of study into solar variations

400 year history of sunspot numbers.

The longest recorded aspect of solar variations are changes in sunspots. The first record of sunspots dates to around 800 BC in China and the oldest surviving drawing of a sunspot dates to 1128. In 1610, astronomers began using the telescope to make observations of sunspots and their motions. Initial study was focused on their nature and behavior.^[12] Although the physical aspects of sunspots were not identified until the 20th century, observations continued. Study was hampered during the 17th century due to the low number of sunspots during what is now recognized as an extended period of low solar activity, known as the Maunder Minimum. By the 19th century, there was a long enough record of sunspot numbers to infer periodic cycles in sunspot activity. In 1845, Princeton University professors Joseph Henry and Stephen Alexander observed the Sun with a thermopile and determined that sunspots emitted less radiation than surrounding areas of the Sun. The emission of higher than average amounts of radiation later were observed from the solar faculae.^[13]

Around 1900, researchers began to explore connections between solar variations and weather on Earth. Of particular note is the work of Charles Greeley Abbot. Abbot was assigned by the Smithsonian Astrophysical Observatory (SAO) to detect changes in the radiation of the Sun. His team had to begin by inventing instruments to measure solar radiation. Later, when Abbot was head of the SAO, it established a solar station at Calama, Chile to complement its data from Mount Wilson Observatory. He detected 27 harmonic periods within the 273-month Hale cycles, including 7, 13, and 39-month patterns. He looked for connections to weather by means such as matching opposing solar trends during a month to opposing temperature and precipitation trends in cities. With the advent of dendrochronology, scientists such as Waldo S. Glock attempted to connect variation in tree growth to periodic solar variations in the extant record and infer long-term secular variability in the solar constant from similar variations in millennial-scale chronologies.^[14]

Statistical studies that correlate weather and climate with solar activity have been popular for centuries, dating back at least to 1801, when William Herschel noted an apparent connection between wheat prices and sunspot records.^[15] They now often involve high-density global datasets compiled from surface networks and weather satellite observations and/or the forcing of climate models with synthetic or observed solar variability to investigate the detailed processes by which the effects of solar variations propagate through the Earth's climate system.^[16]

Solar activity and irradiance measurement

Direct irradiance measurements have only been available during the last three cycles and are based on a composite of many different observing satellites.^[1][17] However, the correlation between irradiance measurements and other proxies of solar activity make it reasonable to estimate past solar activity. Most important among these proxies is the record of sunspot observations that has been recorded since ~1610. Since sunspots and associated faculae are directly responsible for small changes in the brightness of the sun,^{[citation needed]} they are closely correlated to changes in solar output. Direct measurements of radio emissions from the Sun at 10.7 cm also provide a proxy of solar activity that can be measured from the ground since the Earth's atmosphere is transparent at this wavelength.
Lastly, solar flares are a type of solar activity that can impact human life on Earth by affecting electrical systems, especially satellites. Flares usually occur in the presence of sunspots, and hence the two are correlated, but flares themselves make only tiny perturbations of the solar luminosity.

Recently it has been claimed that the total solar irradiance is varying in ways that are not duplicated by changes in sunspot observations or radio emissions, though Willson, DeWitte, and others have pointed out that these shifts in irradiance may be no more than the result of calibration problems in the measuring satellites.^[18][19] These speculations also admit the possibility that a small long-term trend might exist in solar irradiance.^[20]

Sunspots

Graph showing proxies of solar activity, including changes in sunspot number and cosmogenic isotope production.

Sunspots are relatively dark areas on the radiating 'surface' (photosphere) of the Sun where intense magnetic activity inhibits convection and cools the photosphere. Faculae are slightly brighter areas that form around sunspot groups as the flow of energy to the photosphere is re-established and both the normal flow and the sunspot-blocked energy elevate the radiating 'surface' temperature. Scientists have speculated on possible relationships between sunspots and solar luminosity since the historical sunspot area record began in the 17th century.^[21][22] Correlations are now known to exist with decreases in luminosity caused by sunspots (generally < - 0.3%) and increases (generally < + 0.05%) caused both by faculae that are associated with active regions as well as the magnetically active 'bright network'.^[23]

Modulation of the solar luminosity by magnetically active regions was confirmed by satellite measurements of total solar irradiance (TSI) by the ACRIM1 experiment on the Solar Maximum Mission (launched in 1980).^[23] The modulations were later confirmed in the results of the ERB experiment launched on the Nimbus 7 satellite in 1978,^[24] and satellite observation of solar irradiance continues today with ACRIM-3 and other satellite measurements.^[1] Sunspots in magnetically active regions are cooler and 'darker' than the average photosphere and cause temporary decreases in TSI of as much as 0.3%. Faculae in magnetically active regions are hotter and 'brighter' than the average photosphere and cause temporary increases in TSI.

The net effect during periods of enhanced solar magnetic activity is increased radiant output of the sun because faculae are larger and persist longer than sunspots. Conversely, periods of lower solar magnetic activity and fewer sunspots (such as the Maunder Minimum) may correlate with times of lower terrestrial irradiance from the sun.^[25]

There had been some suggestion that variations in the solar diameter might also cause significant variations in output. But recent work, mostly from the Michelson Doppler Imager instrument on SOHO, shows these changes to be small, about 0.001%, much less than the effect of magnetic activity changes (Dziembowski et al., 2001).

Various studies have been made using sunspot number (for which records extend over hundreds of years) as a proxy for solar output (for which good records only extend for a few decades). Also, ground instruments have been calibrated by comparison with high-altitude and orbital instruments. Researchers have combined present readings and factors to adjust historical data. Other proxy data – such as the abundance of cosmogenic isotopes – have been used to infer solar magnetic activity and thus likely brightness. Sunspot activity has been measured using the Wolf number for about 300 years. This index (also known as the Zürich number) uses both the number of sunspots and the number of groups of sunspots to compensate for variations in measurement. A 2003 study by Ilya Usoskin of the University of Oulu, Finland found that sunspots had been more frequent since the 1940s than in the previous 1150 years.^[26]

Reconstruction of solar activity over 11,400 years. Period of equally high activity over 8,000 years ago marked.

Sunspot numbers over the past 11,400 years have been reconstructed using carbon-14-based dendrochronology (tree ring dating). The level of solar activity during the past 70 years is exceptional – the last period of similar magnitude occurred around 9,000 years ago (during the warm Boreal period).^[27][28] The Sun was at a similarly high level of magnetic activity for only ~10% of the past 11,400 years, and almost all of the earlier high-activity periods were shorter than the present episode.^[28]

Solar activity events recorded in radiocarbon. Present period is on right. Values since 1900 not shown.

Solar activity events and approximate dates

Event	Start	End
Homeric minimum[29]	950BC	800BC
Oort minimum (see Medieval Warm Period)	1040	1080
Medieval maximum (see Medieval Warm Period)	1100	1250
Wolf minimum	1280	1350
Spörer Minimum	1450	1550
Maunder Minimum	1645	1715
Dalton Minimum	1790	1820
Modern Maximum	1900	present

A list of historical Grand minima of solar activity^[27] includes also Grand minima ca. 690 AD, 360 BC, 770 BC, 1390 BC, 2860 BC, 3340 BC, 3500 BC, 3630 BC, 3940 BC, 4230 BC, 4330 BC, 5260 BC, 5460 BC, 5620 BC, 5710 BC, 5990 BC, 6220 BC, 6400 BC, 7040 BC, 7310 BC, 7520 BC, 8220 BC, 9170 BC.

Solar cycles

The sun undergoes various quasi-periodic changes, the principal one referred to as the solar cycle has an 11-year quasi-period. Only the 11 and closely related 22-year cycles are clear in the observations.

• 11 years: Most obvious is a gradual increase and more rapid decrease of the number of sunspots over a period ranging from 9 to 12 years, called the Schwabe cycle, named after Heinrich Schwabe. Differential rotation of the sun's convection zone (as a function of latitude) consolidates magnetic flux tubes, increases their magnetic field strength and makes them buoyant (see Babcock Model). As they rise through the solar atmosphere they partially block the convective flow of energy, cooling their region of the photosphere, causing 'sunspots'. The Sun's apparent surface, the photosphere, radiates more actively when there are more sunspots. Satellite monitoring of solar luminosity since 1980 has shown there is a direct relationship between the solar activity (sunspot) cycle and luminosity with a solar cycle peak-to-peak amplitude of about 0.1%.^[3] Luminosity has also been found to decrease by as much as 0.3% on a 10-day timescale when large groups of sunspots rotate across the Earth's view and increase by as much as 0.05% for up to 6 months due to faculae associated with the large sunspot groups.^[23]

• 22 years: Hale cycle, named after George Ellery Hale. The magnetic field of the Sun reverses during each Schwabe cycle, so the magnetic poles return to the same state after two reversals.

2,300 year Hallstatt solar variation cycles.

Hypothesized cycles

Periodicity of solar activity with periods longer than the sunspot cycle has been proposed. Some of these proposed longer cycles include:

• 87 years (70–100 years): Gleissberg cycle, named after Wolfgang Gleißberg, is thought to be an amplitude modulation of the 11-year Schwabe Cycle (Sonnett and Finney, 1990),^[30] Braun, et al., (2005).^[31]
• 210 years: Suess cycle (a.k.a. "de Vries cycle"). Braun, et al., (2005).^[31]
• 2,300 years: Hallstatt cycle^[32][33]
• 6000 years (Xapsos and Burke, 2009).^[34]

Other patterns have been detected:

• In carbon-14: 105, 131, 232, 385, 504, 805, 2,241 years (Damon and Sonnett, 1991).
• During the Upper Permian 240 million years ago, mineral layers created in the Castile Formation show cycles of 2,500 years.

The sensitivity of climate to cyclical variations in solar forcing will be higher for longer cycles due to the thermal inertia of the oceans, which acts to damp high frequencies. Using a phenomenological approach, Scafetta and West (2005) found that the climate is 1.5 times as sensitive to 22-year cyclical forcing relative to 11-year cyclical forcing, and that the thermal inertia of the oceans induces a lag of approximately 2.2 (± 2) years in cyclic climate response in the temperature data.^[35]

Predictions based on patterns

• Perry and Hsu (2000) proposed a simple model based on emulating harmonics by multiplying the basic 11-year cycle by powers of 2, which produced results similar to Holocene behavior. Extrapolation suggests a gradual cooling during the next few centuries with intermittent minor warmups and a return to near Little Ice Age conditions within the next 500 years. This cool period then may be followed approximately 1,500 years from now by a return to altithermal conditions similar to the previous Holocene Maximum.^[36]
• There is weak evidence for a quasi-periodic variation in the sunspot cycle amplitudes with a period of about 90 years ("Gleisberg cycle"). These characteristics indicate that the next solar cycle should have a maximum smoothed sunspot number of about 145±30 in 2010 while the following cycle should have a maximum of about 70±30 in 2023.^[37]
• Because carbon-14 cycles are quasi periodic, Damon and Sonett (1989) predict future climate:^[38]

Solar irradiance spectrum above atmosphere and at surface

Solar irradiance and insolation are measures of the amount of sunlight that reaches the Earth. The equipment used might measure optical brightness, total radiation, or radiation in various frequencies. Historical estimates use various measurements and proxies.

Cycle length	Cycle name	Last positive carbon-14 anomaly	Next "warming"
232	--?--	AD 1922 (cool)	AD 2038
208	Suess	AD 1898 (cool)	AD 2210
88	Gleisberg	AD 1986 (cool)	AD 2030

Solar irradiance of Earth and its surface

There are two common meanings for solar irradiance:

• the radiation reaching the upper atmosphere
• the radiation reaching some point within the atmosphere, including the surface.

Various gases within the atmosphere absorb some solar radiation at different wavelengths, and clouds and dust also affect it. Measurements above the atmosphere are needed to determine variations in solar output, to avoid the confounding effects of changes within the atmosphere. There is some evidence that sunshine at the Earth's surface has been decreasing in the last 50 years (see global dimming) possibly caused by increased atmospheric pollution, whilst over roughly the same timespan solar output has been nearly constant.

Milankovitch cycle variations

Some variations in insolation are not due to solar changes but rather due to the Earth moving closer or further from the Sun, or changes in the latitudinal distribution of radiation. These orbital changes or Milankovitch cycles have caused variations of as much as 25% (locally; global average changes are much smaller) in solar insolation over long periods. The most recent significant event was an axial tilt of 24° during boreal summer at near the time of the Holocene climatic optimum.

Solar interactions with Earth

1979–2009: Over the past 3 decades, terrestrial temperature has not correlated with sunspot trends. The top plot is of sunspots, while below is the global atmospheric temperature trend. El Chichón and Pinatubo were volcanoes, while El Niño is part of ocean variability. The effect of greenhouse gas emissions is on top of those fluctuations.

Multiple factors have affected terrestrial climate change, including internal forcings and human influences such as greenhouse gas emissions and land use change on top of any effects of solar variability.

There are several hypotheses for how solar variations may affect Earth. Some variations, such as changes in the size of the Sun, are presently only of interest in the field of astronomy.

Changes in total irradiance

• Total solar irradiance changes slowly on decadal and longer timescales.
• The variation during recent solar magnetic activity cycles has been about 0.1% (peak-to-peak).^[3]
• Variations corresponding to solar changes with periods of 9–13, 18–25, and > 100 years have been detected in sea-surface temperatures.
• In contrast to older reconstructions,^[39] most recent reconstructions of total solar irradiance point to an only small increase of only about 0.05% to 0.1% between Maunder Minimum and the present.^[40][41][42]
• Different composite reconstructions of total solar irradiance observations by satellites show different trends since 1980; see the global warming section below.

Changes in ultraviolet irradiance

• Ultraviolet irradiance (EUV) varies by approximately 1.5 percent from solar maxima to minima, for 200 to 300 nm UV.^[43]
• Energy changes in the UV wavelengths involved in production and loss of ozone have atmospheric effects.
  • The 30 hPa atmospheric pressure level has changed height in phase with solar activity during the last 4 solar cycles.
  • UV irradiance increase causes higher ozone production, leading to stratospheric heating and to poleward displacements in the stratospheric and tropospheric wind systems.^[44]
• A proxy study estimates that UV has increased by 3.0% since the Maunder Minimum.^[45]

Changes in the solar wind and the Sun's magnetic flux

• A more active solar wind and stronger magnetic field reduces the cosmic rays striking the Earth's atmosphere.^[46]
• Variations in the solar wind affect the size and intensity of the heliosphere, the volume larger than the Solar System filled with solar wind particles.
• Cosmogenic production of ¹⁴C and ³⁶Cl show changes tied to solar activity. The production rate of ¹⁰Be and TSI over the past millennium is more complicated because of possible climate influence of ¹⁰Be deposition rate, causing errors in the inferred ¹⁰Be formation rate.^[47]
• Cosmic ray ionization in the upper atmosphere does change, but significant effects are not obvious.
• As the solar coronal-source magnetic flux doubled during the past century, the cosmic-ray flux has decreased by about 15%.^{[citation needed]}
• The Sun's total magnetic flux rose by a factor of 1.41 from 1964–1996 and by a factor of 2.3 since 1901.^{[citation needed]}

Cosmic Ray-Clouds Claim

It has been claimed that changes in ionization affect the abundance of aerosols that serve as the nuclei of condensation for cloud formation.^[48] During periods of low solar activity (during solar minima), more cosmic rays reach Earth, potentially creating ultra-small aerosol particles which are precursors to cloud condensation nuclei.^[49]
Clouds formed from greater amounts of condensation nuclei are brighter, longer lived, and likely to produce less precipitation. It has been speculated that a change in cosmic rays could cause an increase in certain types of clouds, affecting Earth's albedo.

• Galactic cosmic rays have been hypothesized to affect formation of clouds through possible effects on production of cloud condensation nuclei.
• Several percent variation in cosmic rays and in tropospheric ionization occurs when the interplanetary magnetic field changes over the solar cycle, greater than the typically 0.1% variation in total solar irradiance meanwhile.^[50][51]
• Particularly at high latitudes where the shielding effect of Earth's magnetic field is less, some studies suggest cosmic ray variation may impact terrestrial low altitude cloud cover (unlike a lack of correlation with high altitude clouds), making such partially influenced by the solar-driven interplanetary magnetic field (as well as passage through the galactic arms over longer timeframes).^{[50][51][52][53]}

Three subsequent papers demonstrated that production of clouds via cosmic rays could not be explained by nucleation particles. The accelerator results do not produce sufficient, and sufficiently large, particles to result in cloud formation;^[54][55] this includes observations after a major solar storm.^[56] Observations after Chernobyl do not show any induced clouds.^[57]

A 2002 paper immediately refuted Svensmark's hypothesis.^[58] Multiple 2013 papers,^{[56][59][60][61]} and a 2015 paper^[62] could find no correlation between cosmic ray levels and global temperature on the multidecadal timescale of recent warming, as cosmic ray levels do not show a multidecadal trend, upwards or down,^{[63][64][65][66]} or on even longer timescales.^[67][68]

The claim that recent warming is due to cosmic rays is not considered credible.^{[69][70][71][72]}

Other effects due to solar variation

Interaction of solar particles, the solar magnetic field, and the Earth's magnetic field, cause variations in the particle and electromagnetic fields at the surface of the planet. Extreme solar events can affect electrical devices. Weakening of the Sun's magnetic field is believed to increase the number of interstellar cosmic rays which reach Earth's atmosphere, altering the types of particles reaching the surface.

Geomagnetic effects

Solar particles interact with Earth's magnetosphere. Sizes not to scale.

The Earth's polar aurorae are visual displays created by interactions between the solar wind, the solar magnetosphere, the Earth's magnetic field, and the Earth's atmosphere. Variations in any of these affect aurora displays. Solar coronal mass ejections, associated with high solar activity, will produce enhanced auroral activity, and visible aurorae at lower latitudes than usual.

Sudden changes can cause the intense disturbances in the Earth's magnetic fields which are called geomagnetic storms.

Solar proton events

Energetic protons can reach Earth within 30 minutes of a major flare's peak. During such a solar proton event, Earth is showered in energetic solar particles (primarily protons) released from the flare site. Some of these particles spiral down Earth's magnetic field lines, penetrating the upper layers of our atmosphere where they produce additional ionization and may produce a significant increase in the radiation environment.

Galactic cosmic rays

An increase in solar activity (more sunspots) is accompanied by an increase in the "solar wind," which is an outflow of ionized particles, mostly protons and electrons, from the sun. The Earth's geomagnetic field, the solar wind, and the solar magnetic field deflect galactic cosmic rays (GCR). A decrease in solar activity increases the GCR penetration of the troposphere and stratosphere. GCR particles are the primary source of ionization in the troposphere above 1 km (below 1 km, radon is a dominant source of ionization in many areas).
Levels of GCRs have been indirectly recorded by their influence on the production of carbon-14 and beryllium-10. The Hallstatt solar cycle length of approximately 2300 years is reflected by climatic Dansgaard-Oeschger events. The 80–90-year solar Gleissberg cycles appear to vary in length depending upon the lengths of the concurrent 11-year solar cycles, and there also appear to be similar climate patterns occurring on this time scale.

Carbon-14 production

Sunspot record (blue) with ¹⁴C (inverted).

The production of carbon-14 (radiocarbon: ¹⁴C) also is related to solar activity. Carbon-14 is produced in the upper atmosphere when cosmic ray bombardment of atmospheric nitrogen (¹⁴N) induces the Nitrogen to undergo β+ decay, thus transforming into an unusual isotope of carbon with an atomic weight of 14 rather than the more common 12. Because cosmic rays are partially excluded from the Solar System by the outward sweep of magnetic fields in the solar wind, increased solar activity results in a reduction of cosmic rays reaching the Earth's atmosphere and thus reduces ¹⁴C production. Thus the cosmic ray intensity and carbon-14 production vary inversely to the general level of solar activity.^[73]

Therefore, the atmospheric ¹⁴C concentration is lower during sunspot maxima and higher during sunspot minima. By measuring the captured ¹⁴C in wood and counting tree rings, production of radiocarbon relative to recent wood can be measured and dated. A reconstruction of the past 10,000 years shows that the ¹⁴C production was much higher during the mid-Holocene 7,000 years ago and decreased until 1,000 years ago. In addition to variations in solar activity, the long term trends in carbon-14 production are influenced by changes in the Earth's geomagnetic field and by changes in carbon cycling within the biosphere (particularly those associated with changes in the extent of vegetation since the last ice age)^{[citation needed]}

Solar variation and climate

CO₂, temperature, and sunspot activity since 1850

Both long-term and short-term variations in solar activity are hypothesized to affect global climate, but it has proven extremely challenging to directly quantify the link between solar variation and the earth's climate.^[74] The topic continues to be a subject of active study.

As discussed above, there are three suggested mechanisms by which solar variations may have an effect on climate:

• Solar irradiance changes directly affecting the climate ("Radiative forcing"). This is generally considered to be a minor effect, as the amplitudes of the variations in solar irradiance are much too small to have significant effect absent some amplification process.^[11]
• Variations in the ultraviolet component. The UV component varies by more than the total, so if UV were for some (as yet unknown) reason having a disproportionate effect, this might explain a larger solar signal in climate.
• Effects mediated by changes in cosmic rays (which are affected by the solar wind) such as changes in cloud cover.

Early research attempted to find a correlation between weather and sunspot activity, mostly without notable success.^[5][14] Later research has concentrated more on correlating solar activity with global temperature.

Solar forcing 1850–2050 used in a NASA GISS climate model. Recent variation pattern used after 2000.

Crucial to the understanding of possible solar impact on terrestrial climate is accurate measurement of solar forcing. Unfortunately accurate measurement of incident solar radiation is only available since the satellite era, and even that is open to dispute: different groups find different values, due to different methods of cross-calibrating measurements taken by instruments with different spectral sensitivity.[1] Scafetta and Willson found significant variations of solar luminosity between 1980 and 2000.^[75] But Lockwood and Frohlich^[76] find that solar forcing has declined since 1987.

The Intergovernmental Panel on Climate Change (IPCC) Third Assessment Report (TAR) concluded that the measured magnitude of recent solar variation is much smaller than the amplification effect due to greenhouse gases but acknowledges in the same report that there is a low level of scientific understanding with respect to solar variation.^[77][78]

Estimates of long-term solar irradiance changes have decreased since the TAR. However, empirical results of detectable tropospheric changes have strengthened the evidence for solar forcing of climate change. The most likely mechanism is considered to be some combination of direct forcing by changes in total solar irradiance, and indirect effects of ultraviolet (UV) radiation on the stratosphere. Least certain are indirect effects induced by galactic cosmic rays.^[79]

In 2002, Lean et al.^[80] stated that while "There is ... growing empirical evidence for the Sun's role in climate change on multiple time scales including the 11-year cycle", "changes in terrestrial proxies of solar activity (such as the 14C and 10Be cosmogenic isotopes and the aa geomagnetic index) can occur in the absence of long-term (i.e., secular) solar irradiance changes ... because the stochastic response increases with the cycle amplitude, not because there is an actual secular irradiance change." They conclude that because of this, "long-term climate change may appear to track the amplitude of the solar activity cycles," but that "Solar radiative forcing of climate is reduced by a factor of 5 when the background component is omitted from historical reconstructions of total solar irradiance ...This suggests that general circulation model (GCM) simulations of twentieth century warming may overestimate the role of solar irradiance variability." More recently, a study and review of existing literature published in Nature in September 2006 suggests that the evidence is solidly on the side of solar brightness having relatively little effect on global climate, with little likelihood of significant shifts in solar output over long periods of time.^[11][81] Lockwood and Fröhlich, 2007, find that there "is considerable evidence for solar influence on the Earth's pre-industrial climate and the Sun may well have been a factor in post-industrial climate change in the first half of the last century," but that "over the past 20 years, all the trends in the Sun that could have had an influence on the Earth's climate have been in the opposite direction to that required to explain the observed rise in global mean temperatures."^[82] In a study that brought geomagnetic activity into the discussion, as a measure of known solar-terrestrial interaction, Love et al. found a statistically significant correlation between sunspots and geomagnetic activity, but they found no statistically significant correlation between global surface temperature and either sunspot number or geomagnetic activity.^[83]

A paper by Benestad and Schmidt^[84] concludes that "the most likely contribution from solar forcing a global warming is 7 ± 1% for the 20th century and is negligible for warming since 1980." This paper disagrees with the conclusions of a Scafetta and West study,^[85] who claim that solar variability has a significant effect on climate forcing. Based on correlations between specific climate and solar forcing reconstructions, they argue that a "realistic climate scenario is the one described by a large preindustrial secular variability (e.g., the paleoclimate temperature reconstruction by Moberg et al.)^[86] with the total solar irradiance experiencing low secular variability (as the one shown by Wang et al.).^[87] Under this scenario, according to Scafetta and West, the Sun might have contributed 50% of the observed global warming since 1900.^[10] Stott et al. estimate that the residual effects of the prolonged high solar activity during the last 30 years account for between 16% and 36% of warming from 1950 to 1999.^[88]

Effect on global warming

Recent rises in Earth average temperature cannot be explained by solar radiative forcing as its primary cause. This has been deduced via multiple, independent lines of evidence:

Direct measurement and time series

Neither direct measurements nor proxies of solar variation correlate well with Earth global temperature,^[89] particularly in recent decades.^[90][91]

Diurnal criterion

Globally, average diurnal temperature range has decreased.^[92][93][94] That is, daytime temperatures have not risen as fast as nighttime temperatures have warmed. This is the opposite of the expected warming if solar energy (falling primarily or wholly on Earth's dayside, depending on energy regime) were the principal means of forcing. It is, however, the expected pattern if greenhouse gases were preventing radiative escape, which is more prevalent on Earth's nightside.^[95]

Hemispheric and latitudinal criteria

The Northern Hemisphere is warming faster than the Southern Hemisphere.^[96][97] This is the opposite of the expected pattern if the Sun, currently closer to the Earth during Austral Summer, were the principal climate forcing.
In particular, the Southern Hemisphere, with more ocean area and less land area, has a lower albedo ("whiteness") and absorbs more light. The Northern Hemisphere, however, has a higher population, industry, and emissions.
Furthermore, the Arctic region is not only warming faster than the Antarctic, but faster than northern mid-latitudes and subtropics. This, despite polar regions receiving less sun than lower latitudes.

Altitude criterion

Solar forcing should warm Earth's atmosphere roughly evenly by altitude, with some variation by wavelength/energy regime. However, the atmosphere is warming at lower altitudes, and actually cooling at higher altitudes. This is the expected pattern if greenhouse gases are driving temperature,^[98][99] as on Venus.^[100]

Solar variation theory

A 1994 U.S. National Academy of Sciences study concluded that variations in total solar irradiance (TSI) were the most likely cause of significant climate change in the pre-industrial era, before significant human-generated carbon dioxide was put into the atmosphere.^[39]

A 2007 paper by Scafetta and West correlating solar proxy data and lower tropospheric temperature for the preindustrial era, before significant anthropogenic greenhouse forcing, suggested that TSI variations may have contributed to 50% of the global warming observed between 1900 and 2000 (although they conclude "our estimates about the solar effect on climate might be overestimated and should be considered as an upper limit.")^[85] This contrasts with the results from global circulation models that predict solar forcing of climate through direct radiative forcing is too small to explain a significant contribution.^[101] The relative significance of solar variability and other forcings of climate change during the industrial era is an area of ongoing research.

Sunspot and temperature reconstructions from proxy data

In 2000, Peter Stott and other researchers at the Hadley Centre in the United Kingdom published a paper^[102] in which they reported on the most comprehensive model simulations to date of the climate of the 20th century. Their study looked at both "natural forcing agents" (solar variations and volcanic emissions) as well as "anthropogenic forcing" (greenhouse gases and sulphate aerosols). They found that "solar effects may have contributed significantly to the warming in the first half of the century although this result is dependent on the reconstruction of total solar irradiance that is used. In the latter half of the century, we find that anthropogenic increases in greenhouses gases are largely responsible for the observed warming, balanced by some cooling due to anthropogenic sulphate aerosols, with no evidence for significant solar effects." Stott's team found that combining all of these factors enabled them to closely simulate global temperature changes throughout the 20th century. They predicted that continued greenhouse gas emissions would cause additional future temperature increases "at a rate similar to that observed in recent decades". It should be noted that their solar forcing included "spectrally resolved changes in solar irradiance" but not indirect effects mediated through cosmic rays (discussed above and in the following section); these ideas are still being fleshed out.^[103] In addition, the study notes "uncertainties in historical forcing" — in other words, past natural forcing may still be having a delayed warming effect, most likely due to the oceans.^[102] A graphical representation^[104] of the relationship between natural and anthropogenic factors contributing to climate change appears in "Climate Change 2001: The Scientific Basis", a report by the Intergovernmental Panel on Climate Change (IPCC).^[105]

Stott's 2003 work mentioned in the model section above largely revised his assessment, and found a significant solar contribution to recent warming, although still smaller (between 16 and 36%) than that of the greenhouse gases.^[88]
Sami Solanki, the director of the Max Planck Institute for Solar System Research in Katlenburg-Lindau, Germany said:

The sun has been at its strongest over the past 60 years and may now be affecting global temperatures... the brighter sun and higher levels of so-called "greenhouse gases" both contributed to the change in the Earth's temperature, but it was impossible to say which had the greater impact.^[106]

Nevertheless, Solanki agrees with the scientific consensus that the marked upswing in temperatures since about 1980 is attributable to human activity.

"Just how large this role [of solar variation] is, must still be investigated, since, according to our latest knowledge on the variations of the solar magnetic field, the significant increase in the Earth's temperature since 1980 is indeed to be ascribed to the greenhouse effect caused by carbon dioxide."^[107]

Maunder Minimum

One historical long-term correlation between solar activity and climate change is the 1645–1715 Maunder minimum, a period of little or no sunspot activity which partially overlapped the "Little Ice Age" during which cold weather prevailed in Europe. The Little Ice Age encompassed roughly the 16th to the 19th centuries^{[108][109][110]} It is debated whether the low solar activity caused the cooling, or whether the cooling was caused by other factors.
The Spörer Minimum has also been identified with a significant cooling period between 1460 and 1550.^[111] Other indicators of low solar activity during this period are levels of the isotopes carbon-14 and beryllium-10.^[112]

On the other hand, in a 2012 paper, Miller et al. link the Little Ice Age to an "unusual 50-year-long episode with four large sulfur-rich explosive eruptions," and notes "large changes in solar irradiance are not required."^[113]

Recent research had suggested that a new 90-year Maunder minimum would result in a reduction of global average temperatures of about 0.3 °C, which would not be enough to offset the ongoing and forecasted average global temperature increase due to increased forcing from rising levels of carbon dioxide (generally referred to as global warming).^[114]

Correlations to solar cycle length

In 1991, Eigil Friis-Christensen and Knud Lassen of the Danish Meteorological Institute in Copenhagen claimed to see a strong correlation of the length of the solar cycle with temperature changes throughout the northern hemisphere.^[115] Initially, they used sunspot and temperature measurements from 1861 to 1989, but later found that climate records dating back four centuries supported their findings. They reported that the relationship appeared to account for nearly 80 per cent of the measured temperature changes over this period.

Although correlations often can be found, the mechanism behind these correlations is a matter of speculation. In a 2003 paper "Solar activity and terrestrial climate: an analysis of some purported correlations"^[116] Peter Laut demonstrates problems with some of these correlation analyses. Damon and Laut report in Eos^[117] that

the apparent strong correlations displayed on these graphs have been obtained by incorrect handling of the physical data. The graphs are still widely referred to in the literature, and their misleading character has not yet been generally recognized.

Damon and Laut stated that when the graphs are corrected for filtering errors, the sensational agreement with the recent global warming, which drew worldwide attention, has totally disappeared.^[117]

On 6 May 2000, New Scientist magazine reported that Lassen and astrophysicist Peter Thejll had updated Friis-Christensen and Lassen's 1991 research (which originally only went to 1989) and found that while the solar cycle still accounts for about half the temperature rise since 1900, it fails to explain a rise of 0.4 °C since 1980. "The curves diverge after 1980," Thejll said, "and it's a startlingly large deviation. Something else is acting on the climate.... It has the fingerprints of the greenhouse effect."^[118] Likewise a 2005 review by Benestad^[119] found that the solar cycle length does not follow Earth's global mean surface temperature.

Solar variation and weather

There are some suggestions that there may also be regional climate impacts due to the solar activity, such as for the rivers Paraná^[120] and Po.^[121] Measurements from NASA's Solar Radiation and Climate Experiment show that solar UV output is more variable than the total solar irradiance. Climate modelling suggests that low solar activity may result in, for example, colder winters in the US and northern Europe and milder winters in Canada and southern Europe, with little change in globally averaged temperature.^[2] More broadly, links have been suggested between solar cycles, global climate and events like El Nino.^[122] In other research, Daniel J. Hancock and Douglas N. Yarger found "statistically significant relationships between the double [~21-year] sunspot cycle and the 'January thaw' phenomenon along the East Coast and between the double sunspot cycle and 'drought' (June temperature and precipitation) in the Midwest."^[123]

Recent research at CERN's CLOUD facility examined links between cosmic rays and cloud condensation nuclei, demonstrating the effect of high-energy particulate radiation in nucleating aerosol particles which are precursors to cloud condensation nuclei.^[49] Dr. Jasper Kirby, a team leader at CLOUD, said, "At the moment, it [the experiment] actually says nothing about a possible cosmic-ray effect on clouds and climate, but it's a very important first step."^[124][125]

1983–1994 data from the International Satellite Cloud Climatology Project (ISCCP) showed that global low cloud formation was highly correlated with galactic cosmic ray (GCR) flux; subsequent to this period, the correlation breaks down.^[117] Changes of 3–4% in cloudiness and concurrent changes in cloud top temperatures have been correlated to the 11 and 22-year solar (sunspot) cycles, with increased GCR levels during "antiparallel" cycles.^[52]
Global average cloud cover change has been found to be 1.5–2%. Several studies of GCR and cloud cover variations have found positive correlation at latitudes greater than 50° and negative correlation at lower latitudes.^[48] However, not all scientists accept this correlation as statistically significant, and some that do attribute it to other solar variability (e.g. UV or total irradiance variations) rather than directly to GCR changes.^[126][127] Difficulties in interpreting such correlations include the fact that many aspects of solar variability change at similar times, and some climate systems have delayed responses.

Historical perspective

Physicist and historian Spencer R. Weart in The Discovery of Global Warming (2003) writes:

The study of [sun spot] cycles was generally popular through the first half of the century. Governments had collected a lot of weather data to play with and inevitably people found correlations between sun spot cycles and select weather patterns. If rainfall in England didn't fit the cycle, maybe storminess in New England would. Respected scientists and enthusiastic amateurs insisted they had found patterns reliable enough to make predictions. Sooner or later though every prediction failed. An example was a highly credible forecast of a dry spell in Africa during the sunspot minimum of the early 1930s. When the period turned out to be wet, a meteorologist later recalled "the subject of sunspots and weather relationships fell into dispute, especially among British meteorologists who witnessed the discomfiture of some of their most respected superiors." Even in the 1960s he said, "For a young [climate] researcher to entertain any statement of sun-weather relationships was to brand oneself a crank."^[5]

Creationism – Are We Winning The Battle and Losing The War?

Published by Steven Novella under Creationism/ID,Skepticism

Original link:  http://theness.com/neurologicablog/index.php/creationism-are-we-winning-the-battle-and-losing-the-war/

One of the major ambitions of my life is to promote science and critical thinking, which I do under the related banners of scientific skepticism and science-based medicine. This is a huge endeavor, with many layers of complexity. For that reason it is tempting to keep one’s head down, focus on small manageable problems and goals, and not worry too much about the big picture. Worrying about the big picture causes stress and anxiety.

I have been doing this too long to keep my head down, however. I have to worry about the big picture: are we making progress, are we doing it right, how should we alter our strategy, is there anything we are missing?

The answers to these questions are different for each topic we face. While we are involved in one large meta-goal, it is composed of hundreds of sub-goals, each of which may pose their own challenges. Creationism, for example, is one specific topic that we confront within our broader mission or promoting science.

Over my life the defenders of science have won every major battle against creationism, in the form of major court battles, many at the supreme court level. The most recent was Kitzmiller vs Dover, which effectively killed  Intelligent Design as a strategy for pushing creationism into public schools. The courts are a great venue for the side of science, because of the separation clause in the constitution and the way it has been interpreted by the courts. Creationism is a religious belief, pure and simple, and it has no place in a science classroom. Evolution, meanwhile, is an established scientific theory with overwhelming support in the scientific community. It is the exact kind of consensus science that should be taught in the classroom. When we have this debate in the courtroom, where there are rules of evidence and logic, it’s no contest. Logic, facts, and the law are clearly on the side of evolution.

Despite the consistent legal defeat of creationism, over the last 30 years Gallup’s poll of American public belief in creationism has not changed. In 1982 44% of Americans endorsed the statement: “God created humans in their present form.” In 2014 the figure was 42%; in between the figure fluctuated from 40-47% without any trend.

There has been a trend in the number of people willing to endorse the statement that humans evolved without any involvement from God, with an increase from 9 to 19%. This likely reflects a general trend, especially in younger people, away from religious affiliation – but apparently not penetrating the fundamentalist Christian segments of society.

Meanwhile creationism has become, if anything, more of an issue for the Republican party. It seems that any Republican primary candidate must either endorse creationism or at least pander with evasive answers such as, “I am not a scientist” or “teach the controversy” or something similar.

Further, in many parts of the country with a strong fundamentalist Christian population, they are simply ignoring the law with impunity and teaching outright creationism, or at least the made-up “weaknesses” of evolutionary theory.
They are receiving cover from pandering or believing politicians. This is the latest creationist strategy – use “academic freedom” laws to provide cover for teachers who want to introduce creationist propaganda into their science classrooms.

Louisiana is the model for this. Zack Kopplin, who was a high school student when Bobby Jindal signed the law that allows teachers to introduce creationist material into Louisiana classrooms. He has since made it his mission to oppose such laws, and he writes about his frustrations in trying to make any progress. Creationists are simply too politically powerful in the Bible belt.

This brings me back to my core question – how are we doing (at least with respect to the creationism issue)? The battles we have fought needed to be fought and it is definitely a good thing that science and reason won. There are now powerful legal precedents defending the teaching of evolution and opposing the teaching of creationism in public schools, and I don’t mean to diminish the meaning of these victories.

But we have not penetrated in the slightest the creationist culture and political power, which remains solid at around 42% of the US population. It seems to me that the problem is self-perpetuating. Students raised in schools that teach creationism or watered-down evolution and live in families and go to churches that preach creationism are very likely to grow up to be creationists. Some of them will be teachers and politicians.

From one perspective we might say that we held the line defensively against a creationist offense, but that is all – we held the line. Perhaps we need to now figure out a way to go on offense, rather than just waiting to defend against the next creationist offense. The creationists have think tanks who spend their time thinking about the next strategy. At best we have people and organizations (like the excellent National Center for Science Education) who spend their time trying to anticipate the next strategy.

The NCSE’s own description of their mission is, “Defending the teaching of evolution and climate science.” They are in a defensive posture. Again, to be clear, they do excellent and much needed work and I have nothing but praise for them. But looking at the big picture, perhaps we need to add some offensive strategies to our defensive strategies.

I don’t know exactly what form those offensive strategies would take. This would be a great conversation for skeptics to have, however. Rather than just fighting against creationist laws, for example, perhaps we could craft a model pro-science law that will make it more difficult for science teachers to hide their teaching of creationism.
Perhaps we need a federal law to trump any pro-creationist state laws. It’s worth thinking about.

I also think we need a cultural change within the fundamentalist Christian community. This will be a tougher nut to crack. We should, however, be having a conversation with them about how Christian faith can be compatible with science. Faith does not have to directly conflict with the current findings of science. Modeling ways in which Christians can accommodate their faith to science may be helpful. And to be clear – I am not saying that science should accommodate itself to faith, that is exactly what we are fighting against.

Conclusion

As the skeptical movement grows and evolves, I would like to see it mature in the direction where high-level strategizing on major issues can occur. It is still very much a grassroots movement without any real organization. At best there is networking going on, and perhaps that is enough. At the very least we should parlay those networks into goal-oriented strategies on specific issues.

Creationism is one such issue that needs some high-level think tank attention.

‘Natural’ illusions: Biologist’s failed attempt to defend organic food

Iida Ruishalme | May 22, 2015 | Genetic Literacy Project

Original link:  http://www.geneticliteracyproject.org/2015/05/22/natural-illusions-biologists-failed-attempt-to-defend-organic-food/

Here I write of my attempt to defend organic, of the risks of repeating slogans, and of how pieces of worldview are built and change, sometimes as easily as with a comment or two.

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“Yes, Monsanto is pure evil,” I said. This was about a year ago, in 2013, and I was defending science and nuanced thinking in the same sentence, no less. “Monsanto is pure evil,” I said, “but genetic engineering is just a tool and in itself is neither good or bad.” My University course literature had given a balanced view of many possible benefits to GM while highlighting a couple of areas of caution. My main insight on Monsanto came from the movie Food Inc., confirmed by plenty of common internet knowledge and a couple of trusted friends of mine.

I had always considered myself a rational and science-minded person so I was upset when I first heard people object to GMOs for reasons such as not wanting genes in their food (in the late nineties, when the topic was still very new and knowledge scarce) or just because ‘it wasn’t natural’, which I saw as a fear of the unknown.

Later on I was incredibly frustrated to find that a lot of people opposed standard vaccinations going counter to scientific evidence. So when I stumbled on a Facebook page called “We love vaccines and GMOs”, though I didn’t exactly think of my view on genetic engineering as ‘love’, I was happy to find a place to share my frustration. But as I started following their posts I was confronted with something that gave me pause. There were several that criticised organic farming.

I had been a loyal organic consumer for a decade. My vegan friends had talked a lot about how detrimental industrial agriculture was for the environment, and even my favourite ecology teacher back in the University mentioned how important it was to buy organic milk and meat. Living on student subsidies and saving on about everything else, I was convinced that buying ecological produce (In Finland the label actually goes under the name ‘Eco’, and the Swedish label, translated roughly to ‘Demand’, also states the food is ecologically produced. In Switzerland it’s called ‘Bio’ for biologically farmed.) was vital for the environment. Paying twice the price was more than worth it.

I couldn’t just leave the criticism unaddressed. Somebody needed to present a nuanced voice of organic farming, so that people would not group it together with anti-science sentiments. So I started digging. I read about comprehensive meta-analysesof studies where they found that organic food was no more nutritious than conventional produce – News in Standford medicine – Little evidence of health benefits from organic foods (or click for the paper behind paywall), for instance, said:

science simply cannot find any evidence that organic foods are in any way healthier than non-organic ones – and scientists have been comparing the two for over 50 years.

and in Scientific American on: Mythbusting 101 organic farming vs conventional agriculture. Interesting, I thought, but hardly devastating. That wasn’t my reason for choosing organic. I read about how organic was an industry like any other, looking for profit, with all the dirt that entails. Even Michael Pollan criticized the organic industry in his book Omnivore’s dilemma. Well sure. It couldn’t exactly be a charity, could it? Not every company was perfectly principled. It didn’t mean that the whole organic label was bad.

Then I read a Swiss animal welfare organisation statement (article in german) that organic did not necessarily reflect in greater well-being for the animals, that it was more narrowly focused on the farming of crops. As a great animal lover I thought, okay, that’s a pity, for animal products I would have to look for different labels. But I would continue to support organic for the most important point, for the sake of the environment.

I continued. Then there was a study about organic pesticides being no more benign than conventional. Well that was surprising, but made sense now that I thought of it – they would all have to be some kind of chemicals that kill plants and insects. It turns out, when they looked at natural vs synthetic chemicals, researchers had come to the conclusion that natural or not does not make a big difference. As one commenter on that concluded:

Until recently, nobody bothered to look at natural chemicals (such as organic pesticides), because it was assumed that they posed little risk. But when the studies were done, the results were somewhat shocking: you find that about half of the natural chemicals studied are carcinogenic as well. This is a case where everyone (consumers, farmers, researchers) made the same, dangerous mistake. We assumed that “natural” chemicals were automatically better and safer than synthetic materials, and we were wrong. It’s important that we be more prudent in our acceptance of “natural” as being innocuous and harmless.

Find more information from safe fruits and veggies website

I further read about how the risks from pesticides for the consumer were actually very small, and that people feared them much out of proportion! What a relief. Why did so many seem to think the opposite?

Further, there was a study that said organic farming actually contributed more to pollution of groundwater, and then a meta-analysis of more than a hundred studies saying organic had more ammonia and nitrogen run-off per product unit, leading to more eutrophication as well as acidification potential. Ouch. That was not what I would have thought. But considering the imprecise mode of fertilisation (spreading out manure), that too did make sense. Most importantly, also confirmed by several sources (and here and here), I found out that the big issue with organic farming was the yield – forgoing the more efficient synthetic methods meant having one third (or between a half and one fifth) less of end product. Nature News:

Crop yields from organic farming are as much as 34 percent lower than those from comparable conventional farming practices, the analysis finds. Organic agriculture performs particularly poorly for vegetables and some cereal crops such as wheat, which make up the lion’s share of the food consumed around the world.

Cereals and vegetables need lots of nitrogen to grow, suggesting that the yield differences are in large part attributable to nitrogen deficiencies in organic systems, says Seufert.

This in turn meant that scaling up organic farming, we would need to find a third more land to make up for its inefficiency.

When I looked at these studies one by one, my immediate reaction was: surely now that these results were available, where necessary, organic farming practices could be adapted so that they would continue to provide consumers with the best environmentally friendly sources of food. But that relied on an assumption I held that I had so far not even thought of checking.

I thought organic farming was based on evidence, but it wasn’t. It wasn’t designed by studying what would be best for the environment. On the contrary, to my surprise I found it’s roots were actually in biodynamic agriculture – a method that emphasizes spiritual and mystical perspectives on farming. What? How could I have missed such a point for a decade? The picture I was beginning to piece together was that being ‘organic’ was based on the idea that modern farming – industrial agriculture – was bad, and the old ways of farming were better. That whatever natural was, that was better.

So anything created specifically in a lab, with intention, aim, and knowledge – anything synthetic – had to be bad. Genetic engineering (which I had thought would go hand-in-hand with many of the ecological intentions of organic farming) had to be especially bad. And companies working on modern agricultural approaches were simply the worst.

I couldn’t believe what I had just read.

While I was in the midst of what I call my organic crisis, I saw another post that was at odds with my world view. But this one was over the top. A YouTube video called “I love Monsanto”. I clicked on the link in disbelief as I had never seen those three words in the same sentence before. Obviously it was an attention-seeking stunt, and it worked. The man in the video, Dusty, went through one Monsanto-claim after another, and punched them full of holes. And quite easily too. He urged his watchers not to take his word but to read up on the claims themselves. I did. Alleged lawsuits, bad treatment of employees, terminator seeds, Indian farmer suicides, abusing and controlling farmers, patents, notorious history, being evil, falsifying research, and on and on. I came up empty. There was nothing terrible left that I could accuse Monsanto of. I even skimmed back and forth in the movie Food Inc., and looked for supporting sources online, but instead of finding ammunition, I found more holes. With a few emotional testimonies and dramatised footage the movie painted a worldview which made all its following insinuations plausible. I couldn’t believe I had not seen the gaps in its presentation on the first viewing. Why didn’t they interview any science experts or organisations? What about the FDA? Union representatives? Farming organisations? Lawyers? Immigration officials? Where was the actual evidence?

I was embarrassed and angry over how easily I had been fooled. Not only had I parroted silly slogans such as ‘Monsanto is evil’, but I had long and determinedly supported a branch of agriculture that I thought was making the world better. It dawned on me that the only improvements in fact being made were the ones in the minds of myself and the other organic supporters – thinking better of ourselves for making such ethical choices. I had shunned others for using the ‘natural’ argument, but with my wallet I had supported the idea that ‘natural’ methods were best in a mysterious way that was above and beyond evidence.

I began to question if there even was a ‘natural way to farm’? If natural was defined by, say, the exclusion of human activities, then surely there was nothing natural to farming. On the other hand, if we accepted humans as a part of nature, and our continued innovations as part of *our nature*, then all farming was natural. Saying that more traditional farming practices would be inherently better than those using more advanced technology wasn’t a concept that could be settled by a romantic appeal to nature. Only careful definitions of ‘better’, followed by observations, testing, and evaluation of evidence could tell us something about that.

Another thing which may or may not be considered natural, is how incredibly many humans there are on this planet today. My reading has made me accept that innovations like synthetic pesticides, fertilisers, and enhanced crops are important in the quest of keeping everybody fed. I have even begun to accept that Monsanto – gasp – could play a part in making the world better. As I see it, the best kind of agriculture going forward should be a scientifically oriented one. It should be free to combine the best methods whether they be derived from old traditions or created in the lab, using what makes most sense, in order to arrive at efficient and environmentally friendly ways of farming. And what has made me happy indeed, is realising that this is already being done – just look at Integrated Pest Management, crops adapted to withstand harsher environments, and Conservation tillage or No-till.

Organic labels on the other hand are not adapting. Actually, it appears they are spending considerable sums of money to mislead the public about science (see here, here and here). That is not something I can approve of. And I am not ready to give up one third more land to support the appealing idea of ‘being natural’. That is land which isn’t there. Land which comprises the last dwindling habitats for wild-life – the actual nature.

I am still searching for that label that would say ‘buying this will make the world a better place’. And if I do find one, I will do a proper background-check to see if I can verify its claims. I’ve realised that I am in no way immune to basing my views on unchecked assumptions, and I shouldn’t judge others for making the same mistake. Having to change a deep-seated world view can be exhausting and painful. I am thankful for this experience and see it as a reminder to stay respectful of others, no matter what beliefs they may hold. We can help each other in remaining open for opportunities to learn.

Published originally in the Skepti Forum blog: Iida Ruishalme’s 500 words – Natural Assumptions and my own blog Thoughtscapism.

Iida Ruishalme is a writer and a science communicator who holds a M.Sc. in Biology from Sweden. She is a contributor to both Genetic Literacy Project and Skepti-Forum.org. She blogs over at Thoughtscapism. Follow her on twitter: @Thoughtscapism or on her Facebook page.

Some pushback against Obama’s ridiculous climate remarks at the Coast Guard commencement

Anthony Watts 

May 21, 2015

 

Original link:  http://wattsupwiththat.com/2015/05/21/some-pushback-against-obamas-ridiculous-climate-remarks-at-the-coast-guard-commencement/

 

Did human-caused climate change lead to war in Syria?Based only on the mainstream press headlines, you almost certainly would think so.

Reading further into the articles where the case is laid out, a few caveats appear, but the chain of events seems strong.

The mechanism? An extreme drought in the Fertile Crescent region—one that a new study finds was made worse by human greenhouse gas emissions—added a spark to the tinderbox of tensions that had been amassing in Syria for a number of years under the Assad regime (including poor water management policies).

It is not until you dig pretty deep into the technical scientific literature, that you find out that the anthropogenic climate change impact on drought conditions in the Fertile Crescent is extremely minimal and tenuous—so much so that it is debatable as to whether it is detectable at all.

This is not to say that a strong and prolonged drought didn’t play some role in the Syria’s pre-war unrest—perhaps it did, perhaps it didn’t (a debate we leave up to folks much more qualified than we are on the topic)—but that the human-influenced climate change impact on the drought conditions was almost certainly too small to have mattered.

In other words, the violence would almost certainly have occurred anyway.

Several tidbits buried in the scientific literature are relevant to assessing the human impact on the meteorology behind recent drought conditions there.

It is true that climate models do project a general drying trend in the Mediterranean region (including the Fertile Crescent region in the Eastern Mediterranean) as the climate warms under increasing greenhouse gas concentrations.  There are two components to the projected drying. The first is a northward expansion of the subtropical high pressure system that typically dominates the southern portion of the region. This poleward expansion of the high pressure system would act to shunt wintertime storm systems northward, increasing precipitation over Europe but decreasing precipitation across the Mediterranean.  The second component is an increase in the temperature which would lead to increased evaporation and enhanced drying.

Our analysis will show that the connection between this drought and human-induced climate change is tenuous at best,  and tendentious at worst.

An analysis in the new headline-generating paper by Colin Kelley and colleagues that just appeared in the Proceeding of the National Academy of Sciences shows the observed trend in the sea level pressure across the eastern Mediterranean as well as the trend projected to have taken place there by a collection of climate models. We reproduce this graphic as Figure 1.  If the subtropical high is expanding northward over the region, the sea level pressure ought to be on the rise. Indeed, the climate models (bottom panel) project a rise in the surface pressure over the 20^th century (blue portion of the curve) and predict even more of a rise into the future (red portion of the curve).
However, the observations (top panel, green line) do not corroborate the model hypothesis under the normative rules of science. Ignoring the confusing horizontal lines included by the authors, several things are obvious. First, the level of natural variability is such that no overall trend is readily apparent.

[Note: The authors identify an upwards trend in the observations and describe it as being “marginally significant (P < 0.14)”. In  nobody’s book  (except, we guess, these authors) is a P-value of 0.14 “marginally significant”—it is widely accepted in the scientific literature that P-values must be less than 0.05 for them to be considered statistically significant (i.e., there is a less than 1 in 20 chance that chance alone would produce a similar result). That’s normative science. We’ve seen some rather rare cases where authors attached the term “marginally” significant to P-values up to 0.10, but 0.14 (about a 1 in 7 chance that chance didn’t produce it) is taking things a bit far, hence our previous usage of the word “tendentious.”]

Whether  or not there is an identifiable overall upwards trend, the barometric pressure in  the region during the last decade of the record (when the Syrian drought took place) is not at all unusual when compared to other periods  in the region’s pressure history—including periods that took place long before large-scale greenhouse gas emissions were taking place.

Consequently,  there is little in the pressure record to lend credence to the notion that human-induced climate change played a significant role in the region’s recent drought.

Figure 1. Observed (top) and modeled (bottom) sea level pressure for
the Eastern Mediterranean region (figure adapted from Kelley et al., 2015).

Another clue that the human impact on the recent drought was minimal (at best) comes from a 2012 paper in the Journal of Climate by Martin Hoerling and colleagues. In that paper, Hoerling et al. concluded that about half of the trend towards late-20th century dry conditions in the Mediterranean region was potentially attributable to human emissions of greenhouse gases and aerosols.   They found that climate models run with increasing concentrations of greenhouse gases and aerosols produce drying across the Mediterranean region in general. However, the subregional patterns of the drying are sensitive to the patterns of sea surface temperature (SST) variability and change. Alas, the patterns of SST changes are quite different in reality than they were projected to be by the climate models. Hoerling et al. describe the differences this way “In general, the observed SST differences have stronger meridional [North-South] contrast between the tropics and NH extratropics and also a stronger zonal [East-West] contrast between the Indian Ocean and the tropical Pacific Ocean.”

Figure 2 shows visually what Hoerling was describing—the observed SST change (top) along with the model projected changes (bottom) for the period 1971-2010 minus 1902-1970. Note the complexity that accompanies reality.

Figure 2. Cold season (November–April) sea surface temperature
departures (°C) for the period 1971–2010 minus 1902–70: (top)
observed and (bottom) mean from climate model projections
(from Hoerling et al., 2012).

Hoerling et al. show that in the Fertile Crescent region, the drying produced by climate models is particularly enhanced (by some 2-3 times) if the observed patterns of sea surface temperatures are incorporated into the models rather than patterns that would otherwise be projected by the models (i.e., the top portion of Figure 2 is used to drive the model output rather than the bottom portion).

Let’s be clear here.  The models were unable to accurately reproduce the patterns of SST that have been observed as greenhouse gas concentrations increased.  So the observed data were substituted for the predicted value, and then that was used to generate forecasts of changed rainfall.  We can’t emphasize this enough: what was not supposed to happen from climate change was forced into the models that then synthesized rainfall.

Figure 3 shows these results and Figure 4 shows what has been observed. Note that even using the prescribed SST, the model predicted changes in Figure 3 (lower panel) are only about half as much as has been observed to have taken place in the region around Syria (Figure 4, note scale difference). This leaves the other half of the moisture decline largely unexplained.  From Figure 3 (top), you can also see that only about 10mm out of more than 60mm of observed precipitation decline around Syria during the cold season is “consistent with” human-caused climate change as predicted by climate models left to their own devices.

Nor does “consistent with” mean “caused by” it.

Figure 3. Simulated change in cold season precipitation
(mm) over the Mediterranean region based on the ensemble
average (top) of 22 IPCC models run with observed emissions
of greenhouse gases and aerosols and (bottom) of 40 models
run with observed emissions of greenhouse gases and aerosols
with prescribed sea surface temperatures. The difference plots
in the panels are for the period 1971–2010 minus 1902–70
(source: Hoerling et al., 2012).

For comparative purposes, according to the University of East Anglia climate history, the average cold-season rainfall in Syria is 261mm (10.28 inches).  Climate models, when left to their own devices,  predict a decline averaging about 10mm, or 3.8 per cent of the total.  When “prescribed” (some would use the word “fudged”) sea surface temperatures are substituted for their wrong numbers, the decline in rainfall goes up to a whopping 24mm, or 9.1 per cent of the total.  For additional comparative purposes, population has roughly tripled in the last three decades.

Figure 4. Observed change in cold season precipitation for the period
1971–2010 minus 1902–70. Anomalies (mm) are relative to the
1902–2010 (source: Hoerling et al., 2012).

So what you are left with after carefully comparing the patterns of observed changes in the meteorology and climatology of Syria and the Fertile Crescent region to those produced by climate models, is that the lion’s share of the observed changes are left unexplained by the models run with increasing greenhouse gases. Lacking a better explanation, these unexplained changes get chalked up to “natural variability”—and natural variability dominates the observed climate history.

You wouldn’t come to this conclusion from the cursory treatment of climate that is afforded in the mainstream press.  It requires an examination of scientific literature and a good background and understanding of the rather technical research being discussed. Like all issues related to climate change, the devil is in the details, and, in the haste to produce attention grabbing headlines, the details often get glossed over or dismissed.

Our bottom line: the identifiable influence of human-caused climate change on recent drought conditions in the Fertile Crescent was almost certainly not the so-called straw that broke the camel’s back and led to the outbreak of conflict in Syria. The pre-existing (political) climate in the region was plenty hot enough for a conflict to ignite, perhaps partly fuelled by recent drought conditions—conditions which are part and parcel of the region climate and the intensity and frequency of which remain dominated by natural variability, even in this era of increasing greenhouse gas emissions  from human activities.

References:

Hoerling, M., et al., 2012. On the increased frequency of Mediterranean drought. Journal of Climate, 25, 2146-2161.

Kelley, C. P., et al., 2015. Climate change in the Fertile Crescent and implications of the recent Syrian drought. Proceedings of the National Academy of Sciences, doi:10.1073/pnas.1421533112

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The Current Wisdom is a series of monthly articles in which Patrick J. Michaels, director of the Center for the Study of Science, reviews interesting items on global warming in the scientific literature that may not have received the media attention that they deserved, or have been misinterpreted in the popular press.

Arctic and Antarctic Temperature Anomaly & The AMO

The following is partially borrowed from https://www.facebook.com/ClimateNews.ca/photos/a.464539090317538.1073741852.306212519483530/673459936092118/?type=1&theater

NASA recently posted that Greenland is currently losing ice at 238 (or maybe 287) billion tons/year.  When I pointed out that this is only 0.1% of the total Greenland ice mass, I was criticized for not taking into account that  (a), only a very small fraction of the melt could significantly rise sea levels, and that  (b) the melting had been (recently) rising about 2-fold over six year, such that the entire melt could happen before 2100.  Fair enough, though I could point out out other facts that could challenge the criticisms, and that the point of my comment -- scary sound bites out of context that didn't promote scientific literacy about science -- was being ignored.

A new, and critical, fact about arctic warming has just been pointed out by "Climate News" (see link above), one that throws a serious monkey wrench into the entire debate.  I'll repeat the entire post below:

Arctic and Antarctic Temperature Anomaly & The AMO

The 'Atlantic Multidecadal Oscillation' (AMO) entered its warm-phase in the mid 1990's. When this happened, Arctic temperature began to warm and Arctic ice began to decline.

The attached graph [above] shows Arctic and Antarctic temperature anomalies. Notice the increase in Arctic temperature anomaly in the mid 1990's? Something triggered it; and I bet it was the warm-phase of the AMO.

The top graph is the Arctic Temperature Anomaly. The graphic on the right is the AMO Index (graphed [above]). We can clearly see that the Arctic began to warm when the AMO flipped to its warm-phase.
 

Observations seem to show that the Atlantic Multidecadal Oscillation has an influence on Arctic temperature, and on sea ice.

The graph at the bottom shows Antarctic temperature anomaly. As you can see, Antarctica hasn't been warming.

Climate data Source: Remote Sensing Systems (RSS)

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This data, which I doubt was first discovered by Climate News, strongly suggests that the current arctic warm period will come to and end in the early to mid 2020s; that the arctic will cool (at least relatively), and the melting will be reduced significantly.  If data from the Antarctic are any guide, arctic temperatures could even cool back to pre 1990 levels, and ice melting likewise.

All of which brings me back to my point. Frightening numbers posted out of any context only confuse people and counter scientific literacy.  It also suggests that NASA is biased (probably due to Hansen's reign), and so should not be in the in the climate prediction business (though they are of course a necessary part of it).

Greenhouse effect

From Wikipedia, the free encyclopedia

A representation of the exchanges of energy between the source (the Sun), the Earth's surface, the Earth's atmosphere, and the ultimate sink outer space. The ability of the atmosphere to capture and recycle energy emitted by the Earth surface is the defining characteristic of the greenhouse effect.

Another diagram of the greenhouse effect

The greenhouse effect is a process by which thermal radiation from a planetary surface is absorbed by atmospheric greenhouse gases, and is re-radiated in all directions. Since part of this re-radiation is back towards the surface and the lower atmosphere, it results in an elevation of the average surface temperature above what it would be in the absence of the gases.^[1][2]

Solar radiation at the frequencies of visible light largely passes through the atmosphere to warm the planetary surface, which then emits this energy at the lower frequencies of infrared thermal radiation. Infrared radiation is absorbed by greenhouse gases, which in turn re-radiate much of the energy to the surface and lower atmosphere. The mechanism is named after the effect of solar radiation passing through glass and warming a greenhouse, but the way it retains heat is fundamentally different as a greenhouse works by reducing airflow, isolating the warm air inside the structure so that heat is not lost by convection.^[2][3][4]

If an ideal thermally conductive blackbody were the same distance from the Sun as the Earth is, it would have a temperature of about 5.3 °C. However, since the Earth reflects about 30%^[5][6] of the incoming sunlight, this idealized planet's effective temperature (the temperature of a blackbody that would emit the same amount of radiation) would be about −18 °C.^[7][8] The surface temperature of this hypothetical planet is 33 °C below Earth's actual surface temperature of approximately 14 °C.^[9] The mechanism that produces this difference between the actual surface temperature and the effective temperature is due to the atmosphere and is known as the greenhouse effect.^[10]

Earth’s natural greenhouse effect makes life as we know it possible. However, human activities, primarily the burning of fossil fuels and clearing of forests, have intensified the natural greenhouse effect, causing global warming.^[11]

History

The existence of the greenhouse effect was argued for by Joseph Fourier in 1824. The argument and the evidence was further strengthened by Claude Pouillet in 1827 and 1838, and reasoned from experimental observations by John Tyndall in 1859, and more fully quantified by Svante Arrhenius in 1896.^[12][13]
In 1917 Alexander Graham Bell wrote “[The unchecked burning of fossil fuels] would have a sort of greenhouse effect”, and “The net result is the greenhouse becomes a sort of hot-house.”^[14][15] Bell went on to also advocate for the use of alternate energy sources, such as solar energy.^[16]

Mechanism

The Earth receives energy from the Sun in the form UV, visible, and near IR radiation, most of which passes through the atmosphere without being absorbed. Of the total amount of energy available at the top of the atmosphere (TOA), about 50% is absorbed at the Earth's surface. Because it is warm, the surface radiates far IR thermal radiation that consists of wavelengths that are predominantly much longer than the wavelengths that were absorbed (the overlap between the incident solar spectrum and the terrestrial thermal spectrum is small enough to be neglected for most purposes). Most of this thermal radiation is absorbed by the atmosphere and re-radiated both upwards and downwards; that radiated downwards is absorbed by the Earth's surface. This trapping of long-wavelength thermal radiation leads to a higher equilibrium temperature than if the atmosphere were absent.
This highly simplified picture of the basic mechanism needs to be qualified in a number of ways, none of which affect the fundamental process.

The solar radiation spectrum for direct light at both the top of the Earth's atmosphere and at sea level

Synthetic stick absorption spectrum of a simple gas mixture corresponding to the Earth's atmosphere composition based on HITRAN data ^[17] created using Hitran on the Web system.^[18] Green color - water vapor, red - carbon dioxide, WN - wavenumber (caution: lower wavelengths on the right, higher on the left).

• The incoming radiation from the Sun is mostly in the form of visible light and nearby wavelengths, largely in the range 0.2–4 μm, corresponding to the Sun's radiative temperature of 6,000 K.^[19] Almost half the radiation is in the form of "visible" light, which our eyes are adapted to use.^[20]
• About 50% of the Sun's energy is absorbed at the Earth's surface and the rest is reflected or absorbed by the atmosphere. The reflection of light back into space—largely by clouds—does not much affect the basic mechanism; this light, effectively, is lost to the system.
• The absorbed energy warms the surface. Simple presentations of the greenhouse effect, such as the idealized greenhouse model, show this heat being lost as thermal radiation. The reality is more complex: the atmosphere near the surface is largely opaque to thermal radiation (with important exceptions for "window" bands), and most heat loss from the surface is by sensible heat and latent heat transport. Radiative energy losses become increasingly important higher in the atmosphere largely because of the decreasing concentration of water vapor, an important greenhouse gas. It is more realistic to think of the greenhouse effect as applying to a "surface" in the mid-troposphere, which is effectively coupled to the surface by a lapse rate.
• The simple picture assumes a steady state. In the real world there is the diurnal cycle as well as seasonal cycles and weather. Solar heating only applies during daytime. During the night, the atmosphere cools somewhat, but not greatly, because its emissivity is low, and during the day the atmosphere warms. Diurnal temperature changes decrease with height in the atmosphere.
• Within the region where radiative effects are important the description given by the idealized greenhouse model becomes realistic: The surface of the Earth, warmed to a temperature around 255 K, radiates long-wavelength, infrared heat in the range 4–100 μm.^[19] At these wavelengths, greenhouse gases that were largely transparent to incoming solar radiation are more absorbent.^[19] Each layer of atmosphere with greenhouses gases absorbs some of the heat being radiated upwards from lower layers. It re-radiates in all directions, both upwards and downwards; in equilibrium (by definition) the same amount as it has absorbed. This results in more warmth below. Increasing the concentration of the gases increases the amount of absorption and re-radiation, and thereby further warms the layers and ultimately the surface below.^[8]
• Greenhouse gases—including most diatomic gases with two different atoms (such as carbon monoxide, CO) and all gases with three or more atoms—are able to absorb and emit infrared radiation. Though more than 99% of the dry atmosphere is IR transparent (because the main constituents—N₂, O₂, and Ar—are not able to directly absorb or emit infrared radiation), intermolecular collisions cause the energy absorbed and emitted by the greenhouse gases to be shared with the other, non-IR-active, gases.

Greenhouse gases

By their percentage contribution to the greenhouse effect on Earth the four major gases are:^[21][22]

• water vapor, 36–70%
• carbon dioxide, 9–26%
• methane, 4–9%
• ozone, 3–7%

The major non-gas contributor to the Earth's greenhouse effect, clouds, also absorb and emit infrared radiation and thus have an effect on radiative properties of the atmosphere.^[22]

Role in climate change

The Keeling Curve of atmospheric CO₂ concentrations measured at Mauna Loa Observatory.

Atmospheric gases only absorb some wavelengths of energy but are transparent to others. The absorption patterns of water vapor (blue peaks) and carbon dioxide (pink peaks) overlap in some wavelengths. Carbon dioxide is not as strong a greenhouse gas as water vapor, but it absorbs energy in wavelengths (12-15 micrometers) that water vapor does not, partially closing the “window” through which heat radiated by the surface would normally escape to space. (Illustration NASA, Robert Rohde)^[23]

Strengthening of the greenhouse effect through human activities is known as the enhanced (or anthropogenic) greenhouse effect.^[24] This increase in radiative forcing from human activity is attributable mainly to increased atmospheric carbon dioxide levels.^[25] According to the latest Assessment Report from the Intergovernmental Panel on Climate Change, "most of the observed increase in globally averaged temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations".^[26]

CO₂ is produced by fossil fuel burning and other activities such as cement production and tropical deforestation.^[27] Measurements of CO₂ from the Mauna Loa observatory show that concentrations have increased from about 313 ppm^[28] in 1960 to about 389 ppm in 2010. It reached the 400ppm milestone on May 9, 2013.^[29] The current observed amount of CO₂ exceeds the geological record maxima (~300 ppm) from ice core data.^[30] The effect of combustion-produced carbon dioxide on the global climate, a special case of the greenhouse effect first described in 1896 by Svante Arrhenius, has also been called the Callendar effect.

Over the past 800,000 years,^[31] ice core data shows that carbon dioxide has varied from values as low as 180 parts per million (ppm) to the pre-industrial level of 270ppm.^[32] Paleoclimatologists consider variations in carbon dioxide concentration to be a fundamental factor influencing climate variations over this time scale.^[33][34]

Real greenhouses

A modern Greenhouse in RHS Wisley

The "greenhouse effect" of the atmosphere is named by analogy to greenhouses which get warmer in sunlight, but the mechanism by which the atmosphere retains heat is different.^[35] A greenhouse works primarily by allowing sunlight to warm surfaces inside the structure, but then preventing absorbed heat from leaving the structure through convection, i.e. sensible heat transport. The "greenhouse effect" heats the Earth because greenhouse gases absorb outgoing radiative energy, heating the atmosphere which then emits radiative energy with some of it going back towards the Earth.

A greenhouse is built of any material that passes sunlight, usually glass, or plastic. It mainly heats up because the Sun warms the ground inside, which then warms the air in the greenhouse. The air continues to heat because it is confined within the greenhouse, unlike the environment outside the greenhouse where warm air near the surface rises and mixes with cooler air aloft. This can be demonstrated by opening a small window near the roof of a greenhouse: the temperature will drop considerably. It has also been demonstrated experimentally (R. W. Wood, 1909) that a "greenhouse" with a cover of rock salt (which is transparent to infra red) heats up an enclosure similarly to one with a glass cover.^[4] Thus greenhouses work primarily by preventing convective cooling.^[3][36]

In contrast, the greenhouse effect heats the Earth because rather than retaining (sensible) heat by physically preventing movement of the air, greenhouse gases act to warm the Earth by re-radiating some of the energy back towards the surface. This process may exist in real greenhouses, but is comparatively unimportant there.

Bodies other than Earth

In the Solar System, Mars, Venus, and the moon Titan also exhibit greenhouse effects; that on Venus is particularly large, due to its atmosphere, which consists mainly of dense carbon dioxide.^[37] Titan has an anti-greenhouse effect, in that its atmosphere absorbs solar radiation but is relatively transparent to infrared radiation. Pluto also exhibits behavior superficially similar to the anti-greenhouse effect.^[38][39]

A runaway greenhouse effect occurs if positive feedbacks lead to the evaporation of all greenhouse gases into the atmosphere.^[40] A runaway greenhouse effect involving carbon dioxide and water vapor is thought to have occurred on Venus.^[41]