Updated May 11 with text added at the end.
You only have to compare Sea Surface Temperatures (SST) from HADSST3
with estimates of Global Mean Surface Temperatures (GMST) from Hadcrut4
and RSS.
This first graph shows how global SST has varied since 1850. There are
obvious changepoints where the warming or cooling periods have occurred.
This graph shows in green Hadcrut4 estimates of global surface
temperature, including ocean SST, and near surface air temperatures over
land. The blue line from RSS tracks lower tropospheric air temperatures
measured by satellites, not near the surface but many meters higher.
Finally, the red line is again Hadsst3 global SST All lines use 30-month
averages to reduce annual noise and display longer term patterns.
Strikingly, SST and GMST are almost synonymous from the beginning
until about 1980. Then GMST diverges with more warming than global SST.
Satellite TLT shows the same patterns but with less warming than the
surface. Curious as to the post 1980s patterns, I looked into HADSST3
and found NH SST warmed much more strongly during that period.
This graph shows how warming from circulations in the Northern
Pacific and Northern Atlantic drove GMST since 1980. And it suggests
that since 2005 NH SST is no longer increasing, and may turn toward
cooling.
Surface Heat Flux from Ocean to Air
Now one can read convoluted explanations about how rising CO2 in the
atmosphere can cause land surface heating which is then transported over
the ocean and causes higher SST. But the interface between ocean and
air is well described and measured. Not surprisingly it is the warmer
ocean water sending heat into the atmosphere, and not the other way
around.
The graph displays measures of heat flux in the sub-tropics during a
21-day period in November. Shortwave solar energy shown above in green
labeled radiative is stored in the upper 200 meters of the ocean. The
upper panel shows the rise in SST (Sea Surface Temperature) due to net
incoming energy. The yellow shows latent heat cooling the ocean,
(lowering SST) and transferring heat upward, driving convection.
From
An Investigation of Turbulent Heat Exchange in the Subtropics
James B. Edson
“One can think of the ocean as a capacitor for the MJO (Madden-Julian
Oscillation), where the energy is being accumulated when there is a net
heat flux into the ocean (here occurring to approximately November 24)
after which it is released to the atmosphere during the active phase of
the MJO under high winds and large latent heat exchange.”
http://www.onr.navy.mil/reports/FY13/mmedson.pdf
Conclusion
As we see in the graphs ocean circulations change sea surface
temperatures which then cause global land and sea temperatures to
change. Thus, oceans make climate by making temperature changes.
On another post I describe how oceans also drive precipitation, the
other main determinant of climate. Oceans make rain, and the processes
for distributing rain over land are shown here: https://rclutz.wordpress.com/2015/04/30/here-comes-the-rain-again/
And a word from Dr. William Gray:
“Changes in the ocean’s deep circulation currents appears to be, by
far, the best physical explanation for the observed global surface
temperature changes (see Gray 2009, 2011, 2012, 2012). It seems
ridiculous to me for both the AGW advocates and us skeptics to so
closely monitor current weather and short-time climate change as
indication of CO2’s influence on our climate. This assumes that the much
more dominant natural climate changes that have always occurred are no
longer in operation or have relevance.”
http://www.icecap.us/
Indeed, Oceans Make Climate, or as Dr. Arnd Bernaerts put it:
“Climate is the continuation of oceans by other means.”
Update May 11, 2015
Kenneth Richards provided some supporting references in a comment at
Paul Homewood’s site. They are certainly on point especially this one:
“Examining data sets of surface heat flux during the last few decades
for the same region, we find that the SST warming was not a consequence
of atmospheric heat flux forcing. Conversely, we suggest that long-term
SST warming drives changes in atmosphere parameters at the sea surface,
most notably an increase in latent heat flux, and that an acceleration
of the hydrological cycle induces a strengthening of the trade winds and
an acceleration of the Hadley circulation.”
That quote is from Servain et al, unfortunately behind a paywall. The paper is discussed here:
http://hockeyschtick.blogspot.ca/2014/09/new-paper-finds-climate-of-tropical.html
Full comment from Richards:
http://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-13-00651.1
The surface of the world’s oceans has been warming since the beginning
of industrialization. In addition to this, multidecadal sea surface
temperature (SST) variations of internal [natural] origin exist.
Evidence suggests that the North Atlantic Ocean exhibits the strongest
multidecadal SST variations and that these variations are connected to
the overturning circulation. This work investigates the extent to which
these internal multidecadal variations have contributed to enhancing or
diminishing the trend induced by the external radiative forcing,
globally and in the North Atlantic. A model study is carried out wherein
the analyses of a long control simulation with constant radiative
forcing at preindustrial level and of an ensemble of simulations with
historical forcing from 1850 until 2005 are combined. First, it is noted
that global SST trends calculated from the different historical
simulations are similar, while there is a large disagreement between the
North Atlantic SST trends. Then the control simulation is analyzed,
where a relationship between SST anomalies and anomalies in the Atlantic
meridional overturning circulation (AMOC) for multidecadal and longer
time scales is identified. This relationship enables the extraction of
the AMOC-related SST variability from each individual member of the
ensemble of historical simulations and then the calculation of the SST
trends with the AMOC-related variability excluded. For the global SST
trends this causes only a little difference while SST trends with
AMOC-related variability excluded for the North Atlantic show closer
agreement than with the AMOC-related variability included. From this it
is concluded that AMOC [Atlantic meridional overturning circulation]
variability has contributed significantly to North Atlantic SST trends
since the mid nineteenth century.
http://link.springer.com/article/10.1007%2Fs00382-014-2168-7
After a decrease of SST by about 1 °C during 1964–1975, most apparent in
the northern tropical region, the entire tropical basin warmed up. That
warming was the most substantial (>1 °C) in the eastern tropical
ocean and in the longitudinal band of the intertropical convergence
zone. Examining data sets of surface heat flux during the last few
decades for the same region, we find that the SST [sea surface
temperature] warming was not a consequence of atmospheric heat flux
forcing [greenhouse gases]. Conversely, we suggest that long-term SST
warming drives changes in atmosphere parameters at the sea surface, most
notably an increase in latent heat flux, and that an acceleration of
the hydrological cycle induces a strengthening of the trade winds and an
acceleration of the Hadley circulation. These trends are also
accompanied by rising sea levels and upper ocean heat content over
similar multi-decadal time scales in the tropical Atlantic. Though more
work is needed to fully understand these long term trends, especially
what happens from the mid-1970’s, it is likely that changes in ocean
circulation involving some combination of the Atlantic meridional
overtuning circulation [AMOC] and the subtropical cells are required to
explain the observations.
http://www.nature.com/ncomms/2014/141208/ncomms6752/full/ncomms6752.html
The Atlantic Meridional Overturning Circulation (AMOC) is a key
component of the global climate system, responsible for a large fraction
of the 1.3 PW northward heat transport in the Atlantic basin. Numerical
modelling experiments suggest that without a vigorous AMOC, surface air
temperature in the North Atlantic region would cool by around 1–3 °C,
with enhanced local cooling of up to 8 °C in regions with large sea-ice
changes. Substantial weakening of the AMOC would also cause a southward
shift of the inter-tropical convergence zone, encouraging Sahelian
drought, and dynamic changes in sea level of up to 80 cm along the
coasts of North America and Europe.
A Medley of Potpourri is just what it says; various thoughts, opinions, ruminations, and contemplations on a variety of subjects.
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Monday, May 11, 2015
Hottest year ever? Giant clam reveals Middle Ages were warmer than today
Original link: http://wattsupwiththat.com/2015/01/05/hottest-year-ever-giant-clam-reveals-middle-ages-were-warmer-than-today/
While government science and media begin the ramp-up to claim 2014 as the “hottest year ever” China’s Sea’s biggest bivalve shows that the Middle Ages were warmer than today, when Carbon Dioxide was lower.
From the Chinese Academy of Sciences:
Two recent papers, one is in Earth-Science Reviews and the other is in Chinese Science Bulletin, have studied key chemical contents in micro-drilled giant clams shells and coral samples to demonstrate that in the South China Sea the warm period of the Middle Ages was warmer than the present.
The scientists examined surveys of the ratio of strontium to calcium content and heavy oxygen isotopes, both are sensitive recorders of sea surface temperatures past and present. The aragonite bicarbonate of the Tridacna gigas clam-shell is so fine-grained that daily growth-lines are exposed by micro-drilling with an exceptionally fine drill-bit, allowing an exceptionally detailed time-series of sea-temperature changes to be compiled – a feat of detection worthy of Sherlock Holmes himself.
By using overlaps between successive generations of giant clams and corals, the three scientists – Hong Yan of the Institute of Earth Environment, Chinese Academy of Sciences, Willie Soon of the Harvard-Smithsonian Center for Astrophysics and Yuhong Wang of Fudan University, Shanghai – reconstructed a record of sea-surface temperature changes going back 2500 years.
The Roman and Mediaeval Warm Periods both showed up prominently in the western Pacific and East Asia. Sea surface temperatures varied considerably over the 2500-year period.
Changing patterns of winter and summer temperature variation were also detected, disproving the notion that until the warming of the 20th century there had been little change in global temperatures for at least 1000 years, and confirming that – at least in the South China Sea – there is nothing exceptional about today’s temperatures.
Dr. Yan said: “This new paper adds further material to the substantial body of real-world proxy evidence establishing that today’s global temperature is within natural ranges of past changes.” Dr. Soon added: “The UN’s climate panel should never have trusted the claim that the medieval warm period was mainly a European phenomenon. It was clearly warm in South China Sea too.”
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