Two climate change sceptics, who believe the dangers of global warming are overstated, have put their money where their mouth is and bet $10,000 that the planet will cool over the next decade.
The Russian solar physicists Galina Mashnich and Vladimir Bashkirtsev have agreed the wager with a British climate expert, James Annan.
The pair, based in Irkutsk, at the Institute of Solar-Terrestrial Physics, believe that global temperatures are driven more by changes in the sun's activity than by the emission of greenhouse gases. They say the Earth warms and cools in response to changes in the number and size of sunspots. Most mainstream scientists dismiss the idea, but as the sun is expected to enter a less active phase over the next few decades the Russian duo are confident they will see a drop in global temperatures.
Dr Annan, who works on the Japanese Earth Simulator supercomputer, in Yokohama, said: "There isn't much money in climate science and I'm still looking for that gold watch at retirement. A pay-off would be a nice top-up to my pension."
To decide who wins the bet, the scientists have agreed to compare the average global surface temperature recorded by a US climate centre between 1998 and 2003, with temperatures they will record between 2012 and 2017.
If the temperature drops Dr Annan will stump up the $10,000 (now equivalent to about £5,800) in 2018. If the Earth continues to warm, the money will go the other way.
The bet is the latest in an increasingly popular field of scientific wagers, and comes after a string of climate change sceptics have refused challenges to back their controversial ideas with cash.
Dr Annan first challenged Richard Lindzen, a meteorologist at the Massachusetts Institute of Technology who is dubious about the extent of human activity influencing the climate. Professor Lindzen had been willing to bet that global temperatures would drop over the next 20 years.
No bet was agreed on that; Dr Annan said Prof Lindzen wanted odds of 50-1 against falling temperatures, so would win $10,000 if the Earth cooled but pay out only £200 if it warmed. Seven other prominent climate change sceptics also failed to agree betting terms.
In May, during BBC Radio 4's Today programme, the environmental activist and Guardian columnist George Monbiot challenged Myron Ebell, a climate sceptic at the Competitive Enterprise Institute, in Washington DC, to a £5,000 bet. Mr Ebell declined, saying he had four children to put through university and did not want to take risks.
Most climate change sceptics dispute the findings of the Intergovernmental Panel on Climate Change which suggest that human activity will drive global temperatures up by between 1.4C and 5.8C by the end of the century.
Others, such as the Danish economist Bjorn Lomborg, argue that, although global warming is real, there is little we can do to prevent it and that we would be better off trying to adapt to living in an altered climate.
Dr Annan said bets like the one he made with the Russian sceptics are one way to confront the ideas. He also suggests setting up a financial-style futures market to allow those with critical stakes in the outcome of climate change to gamble on predictions and hedge against future risk.
"Betting on sea level rise would have a very real relevance to Pacific islanders," he said. "By betting on rapid sea-level rise, they would either be able to stay in their homes at the cost of losing the bet if sea level rise was slow, or would win the bet and have money to pay for sea defences or relocation if sea level rise was rapid."
Similar agricultural commodity markets already allow farmers to hedge against bad weather that ruins harvests.
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When you first meet Richard Lindzen, the Alfred P. Sloan professor of meteorology at MIT, senior fellow at the Cato Institute, leading climate “skeptic,” and all-around scourge of James Hansen, Bill McKibben, Al Gore, the Intergovernmental Panel on Climate Change (IPCC), and sundry other climate “alarmists,” as Lindzen calls them, you may find yourself a bit surprised. If you know Lindzen only from the way his opponents characterize him—variously, a liar, a lunatic, a charlatan, a denier, a shyster, a crazy person, corrupt—you might expect a spittle-flecked, wild-eyed loon. But in person, Lindzen cuts a rather different figure. With his gray beard, thick glasses, gentle laugh, and disarmingly soft voice, he comes across as nothing short of grandfatherly.
Thomas Fluharty
Granted, Lindzen is no shrinking violet. A pioneering climate scientist with decades at Harvard and MIT, Lindzen sees his discipline as being deeply compromised by political pressure, data fudging, out-and-out guesswork, and wholly unwarranted alarmism. In a shot across the bow of what many insist is indisputable scientific truth, Lindzen characterizes global warming as “small and . . . nothing to be alarmed about.” In the climate debate—on which hinge far-reaching questions of public policy—them’s fightin’ words.
In his mid-seventies, married with two sons, and now emeritus at MIT, Lindzen spends between four and six months a year at his second home in Paris. But that doesn’t mean he’s no longer in the thick of the climate controversy; he writes, gives myriad talks, participates in debates, and occasionally testifies before Congress. In an eventful life, Lindzen has made the strange journey from being a pioneer in his field and eventual IPCC coauthor to an outlier in the discipline—if not an outcast.
Richard Lindzen was born in 1940 in Webster, Massachusetts, to Jewish immigrants from Germany. His bootmaker father moved the family to the Bronx shortly after Richard was born. Lindzen attended the Bronx High School of Science before winning a scholarship to the only place he applied that was out of town, the Rensselaer Polytechnic Institute, in Troy, New York. After a couple of years at Rensselaer, he transferred to Harvard, where he completed his bachelor’s degree and, in 1964, a doctorate.
Lindzen wasn’t a climatologist from the start—“climate science” as such didn’t exist when he was beginning his career in academia. Rather, Lindzen studied math. “I liked applied math,” he says, “[and] I was a bit turned off by modern physics, but I really enjoyed classical physics, fluid mechanics, things like that.” A few years after arriving at Harvard, he began his transition to meteorology. “Harvard actually got a grant from the Ford Foundation to offer generous fellowships to people in the atmospheric sciences,” he explains. “Harvard had no department in atmospheric sciences, so these fellowships allowed you to take a degree in applied math or applied physics, and that worked out very well because in applied math the atmosphere and oceans were considered a good area for problems. . . . I discovered I really liked atmospheric sciences—meteorology. So I stuck with it and picked out a thesis.”
And with that, Lindzen began his meteoric rise through the nascent field. In the 1970s, while a professor at Harvard, Lindzen disproved the then-accepted theory of how heat moves around the Earth’s atmosphere, winning numerous awards in the process. Before his 40th birthday, he was a member of the National Academy of Sciences. In the mid-1980s, he made the short move from Harvard to MIT, and he’s remained there ever since. Over the decades, he’s authored or coauthored some 200 peer-reviewed papers on climate.
Where Lindzen hasn’t remained is in the mainstream of his discipline. By the 1980s, global warming was becoming a major political issue. Already, Lindzen was having doubts about the more catastrophic predictions being made. The public rollout of the “alarmist” case, he notes, “was immediately accompanied by an issue of Newsweek declaring all scientists agreed. And that was the beginning of a ‘consensus’ argument. Already by ’88 the NewYork Times had literally a global warming beat.” Lindzen wasn’t buying it. Nonetheless, he remained in the good graces of mainstream climate science, and in the early 1990s, he was invited to join the IPCC, a U.N.-backed multinational consortium of scientists charged with synthesizing and analyzing the current state of the world’s climate science. Lindzen accepted, and he ended up as a contributor to the 1995 report and the lead author of Chapter 7 (“Physical Climate Processes and Feedbacks”) of the 2001 report. Since then, however, he’s grown increasingly distant from prevalent (he would say “hysterical”) climate science, and he is voluminously on record disputing the predictions of catastrophe.
The Earth’s climate is immensely complex, but the basic principle behind the “greenhouse effect” is easy to understand. The burning of oil, gas, and especially coal pumps carbon dioxide and other gases into the atmosphere, where they allow the sun’s heat to penetrate to the Earth’s surface but impede its escape, thus causing the lower atmosphere and the Earth’s surface to warm. Essentially everybody, Lindzen included, agrees. The question at issue is how sensitive the planet is to increasing concentrations of greenhouse gases (this is called climate sensitivity), and how much the planet will heat up as a result of our pumping into the sky ever more CO2, which remains in the atmosphere for upwards of 1,000 years. (Carbon dioxide, it may be needless to point out, is not a poison. On the contrary, it is necessary for plant life.)
Lindzen doesn’t deny that the climate has changed or that the planet has warmed. “We all agree that temperature has increased since 1800,” he tells me. There’s a caveat, though: It’s increased by “a very small amount. We’re talking about tenths of a degree [Celsius]. We all agree that CO2 is a greenhouse gas. All other things kept equal, [there has been] some warming. As a result, there’s hardly anyone serious who says that man has no role. And in many ways, those have never been the questions. The questions have always been, as they ought to be in science, how much?”
Lindzen says not much at all—and he contends that the “alarmists” vastly overstate the Earth’s climate sensitivity. Judging by where we are now, he appears to have a point; so far, 150 years of burning fossil fuels in large quantities has had a relatively minimal effect on the climate. By some measurements, there is now more CO2 in the atmosphere than there has been at any time in the past 15 million years. Yet since the advent of the Industrial Revolution, the average global temperature has risen by, at most, 1 degree Celsius, or 1.6 degrees Fahrenheit. And while it’s true that sea levels have risen over the same period, it’s believed they’ve been doing so for roughly 20,000 years. What’s more, despite common misconceptions stoked by the media in the wake of Katrina, Sandy, and the recent typhoon in the Philippines, even the IPCC concedes that it has “low confidence” that there has been any measurable uptick in storm intensity thanks to human activity. Moreover, over the past 15 years, as man has emitted record levels of carbon dioxide year after year, the warming trend of previous decades has stopped. Lindzen says this is all consistent with what he holds responsible for climate change: a small bit of man-made impact and a whole lot of natural variability.
The real fight, though, is over what’s coming in the future if humans continue to burn fossil fuels unabated. According to the IPCC, the answer is nothing good. Its most recent Summary for Policymakers, which was released early this fall—and which some scientists reject as too sanguine—predicts that if emissions continue to rise, by the year 2100, global temperatures could increase as much as 5.5 degrees Celsius from current averages, while sea levels could rise by nearly a meter. If we hit those projections, it’s generally thought that the Earth would be rife with crop failures, drought, extreme weather, and epochal flooding. Adios, Miami.
It is to avoid those disasters that the “alarmists” call on governments to adopt policies reducing the amounts of greenhouse gases released into the atmosphere. As a result of such policies—and a fortuitous increase in natural gas production—U.S. greenhouse emissions are at a 20-year low and falling. But global emissions are rising, thanks to massive increases in energy use in the developing world, particularly in China and India. If the “alarmists” are right, then, a way must be found to compel the major developing countries to reduce carbon emissions.
But Lindzen rejects the dire projections. For one thing, he says that the Summary for Policymakers is an inherently problematic document. The IPCC report itself, weighing in at thousands of pages, is “not terrible. It’s not unbiased, but the bias [is] more or less to limit your criticism of models,” he says. The Summary for Policymakers, on the other hand—the only part of the report that the media and the politicians pay any attention to—“rips out doubts to a large extent. . . . [Furthermore], government representatives have the final say on the summary.” Thus, while the full IPPC report demonstrates a significant amount of doubt among scientists, the essentially political Summary for Policymakers filters it out.
Lindzen also disputes the accuracy of the computer models that climate scientists rely on to project future temperatures. He contends that they oversimplify the vast complexity of the Earth’s climate and, moreover, that it’s impossible to untangle man’s effect on the climate from natural variability. The models also rely on what Lindzen calls “fudge factors.” Take aerosols. These are tiny specks of matter, both liquid and solid (think dust), that are present throughout the atmosphere. Their effect on the climate—even whether they have an overall cooling or warming effect—is still a matter of debate. Lindzen charges that when actual temperatures fail to conform to the models’ predictions, climate scientists purposely overstate the cooling effect of aerosols to give the models the appearance of having been accurate. But no amount of fudging can obscure the most glaring failure of the models: their inability to predict the 15-year-long (and counting) pause in warming—a pause that would seem to place the burden of proof squarely on the defenders of the models.
Lindzen also questions the “alarmist” line on water vapor. Water vapor (and its close cousin, clouds) is one of the most prevalent greenhouse gases in the atmosphere. According to most climate scientists, the hotter the planet gets, the more water vapor there will be, magnifying the effects of other greenhouse gases, like CO2, in a sort of hellish positive feedback loop. Lindzen disputes this, contending that water vapor could very well end up having a cooling effect on the planet. As the science writer Justin Gillis explained in a 2012 New York Times piece, Lindzen “says the earth is not especially sensitive to greenhouse gases because clouds will react to counter them, and he believes he has identified a specific mechanism. On a warming planet, he says, less coverage by high clouds in the tropics will allow more heat to escape to space, countering the temperature increase.”
If Lindzen is right about this and global warming is nothing to worry about, why do so many climate scientists, many with résumés just as impressive as his, preach imminent doom? He says it mostly comes down to the money—to the incentive structure of academic research funded by government grants. Almost all funding for climate research comes from the government, which, he says, makes scientists essentially vassals of the state. And generating fear, Lindzen contends, is now the best way to ensure that policymakers keep the spigot open.
Lindzen contrasts this with the immediate aftermath of World War II, when American science was at something of a peak. “Science had established its relevance with the A-bomb, with radar, for that matter the proximity fuse,” he notes. Americans and their political leadership were profoundly grateful to the science community; scientists, unlike today, didn’t have to abase themselves by approaching the government hat in hand. Science funding was all but assured.
But with the cuts to basic science funding that occurred around the time of the Vietnam war, taxpayer support for research was no longer a political no-brainer. “It was recognized that gratitude only went so far,” Lindzen says, “and fear was going to be a much greater motivator. And so that’s when people began thinking about . . . how to perpetuate fear that would motivate the support of science.”
A need to generate fear, in Lindzen’s telling, is what’s driving the apocalyptic rhetoric heard from many climate scientists and their media allies. “The idea was, to engage the public you needed an event . . . not just a Sputnik—a drought, a storm, a sand demon. You know, something you could latch onto. [Climate scientists] carefully arranged a congressional hearing. And they arranged for [James] Hansen [author of Storms of My Grandchildren, and one of the leading global warming “alarmists”] to come and say something vague that would somehow relate a heat wave or a drought to global warming.” (This theme, by the way, is developed to characteristic extremes in the late Michael Crichton’s entertaining 2004 novel State of Fear, in which environmental activists engineer a series of fake “natural” disasters to sow fear over global warming.)
Lindzen also says that the “consensus”—the oft-heard contention that “virtually all” climate scientists believe in catastrophic, anthropogenic global warming—is overblown, primarily for structural reasons. “When you have an issue that is somewhat bogus, the opposition is always scattered and without resources,” he explains. “But the environmental movement is highly organized. There are hundreds of NGOs. To coordinate these hundreds, they quickly organized the Climate Action Network, the central body on climate. There would be, I think, actual meetings to tell them what the party line is for the year, and so on.” Skeptics, on the other hand, are more scattered across disciplines and continents. As such, they have a much harder time getting their message across.
Because CO2 is invisible and the climate is so complex (your local weatherman doesn’t know for sure whether it will rain tomorrow, let alone conditions in 2100), expertise is particularly important. Lindzen sees a danger here. “I think the example, the paradigm of this, was medical practice.” He says that in the past, “one went to a physician because something hurt or bothered you, and you tended to judge him or her according to whether you felt better. That may not always have been accurate, but at least it had some operational content. . . . [Now, you] go to an annual checkup, get a blood test. And the physician tells you if you’re better or not and it’s out of your hands.” Because climate change is invisible, only the experts can tell us whether the planet is sick or not. And because of the way funds are granted, they have an incentive to say that the Earth belongs in intensive care.
Richard Lindzen presents a problem for those who say that the science behind climate change is “settled.” So many “alarmists” prefer to ignore him and instead highlight straw men: less credible skeptics, such as climatologist Roy Spencer of the University of Alabama (signatory to a declaration that “Earth and its ecosystems—created by God’s intelligent design and infinite power and sustained by His faithful providence—are robust, resilient, self-regulating, and self-correcting”), the Heartland Institute (which likened climate “alarmists” to the Unabomber), and Senator Jim Inhofe of Oklahoma (a major energy-producing state). The idea is to make it seem as though the choice is between accepting the view of, say, journalist James Delingpole (B.A., English literature), who says global warming is a hoax, and that of, say, James Hansen (Ph.D., physics, former head of the NASA Goddard Institute for Space Studies), who says that we are moving toward “an ice-free Antarctica and a desolate planet without human inhabitants.”
But Lindzen, plainly, is different. He can’t be dismissed. Nor, of course, is he the only skeptic with serious scientific credentials. Judith Curry, the chair of the School of Earth and Atmospheric Sciences at Georgia Tech, William Happer, professor of physics at Princeton, John Christy, a climate scientist honored by NASA, now at the University of Alabama, and the famed physicist Freeman Dyson are among dozens of scientists who have gone on record questioning various aspects of the IPCC’s line on climate change. Lindzen, for his part, has said that scientists have called him privately to thank him for the work he’s doing.
But Lindzen, perhaps because of his safely tenured status at MIT, or just because of the contours of his personality, is a particularly outspoken and public critic of the consensus. It’s clear that he relishes taking on the “alarmists.” It’s little wonder, then, that he’s come under exceptionally vituperative attack from many of those who are concerned about the impact of climate change. It also stands to reason that they might take umbrage at his essentially accusing them of mass corruption with his charge that they are “stoking fear.”
Take Joe Romm, himself an MIT Ph.D., who runs the climate desk at the left-wing Center for American Progress. On the center’s blog, Romm regularly lights into Lindzen. “Lindzen could not be more discredited,” he says in one post. In another post, he calls Lindzen an “uber-hypocritical anti-scientific scientist.” (Romm, it should be noted, is a bit more measured, if no less condescending, when the klieg lights are off. “I tend to think Lindzen is just one of those scientists whom time and science has passed by, like the ones who held out against plate tectonics for so long,” he tells me.) Seldom, however, does Romm stoop to explain what grounds justify dismissing Lindzen’s views with such disdain.
Andrew Dessler, a climatologist at Texas A&M University, is another harsh critic of Lindzen. As he told me in an emailed statement, “Over the past 25 years, Dr. Lindzen has published several theories about climate, all of which suggest that the climate will not warm much in response to increases in atmospheric CO2. These theories have been tested by the scientific community and found to be completely without merit. Lindzen knows this, of course, and no longer makes any effort to engage with the scientific community about his theories (e.g., he does not present his work at scientific conferences). It seems his main audience today is Fox News and the editorial board of the Wall Street Journal.”
The Internet, meanwhile, is filled with hostile missives directed at Lindzen. They’re of varying quality. Some, written by climate scientists, are point-by-point rebuttals of Lindzen’s scholarly work; others, angry ad hominem screeds full of heat, signifying nothing. (When Lindzen transitioned to emeritus status last year, one blog headlined the news “Denier Down: Lindzen Retires.”)
For decades, Lindzen has also been dogged by unsubstantiated accusations of corruption—specifically, that he’s being paid off by the energy industry. He denies this with a laugh.
“I wish it were so!” What appears to be the primary source for this calumny—a Harper’s magazine article from 1995—provides no documentation for its assertions. But that hasn’t stopped the charge from being widely disseminated on the Internet.
One frustrating feature of the climate debate is that people’s outlook on global warming usually correlates with their political views. So if a person wants low taxes and restrictions on abortion, he probably isn’t worried about climate change. And if a person supports gay marriage and raising the minimum wage, he most likely thinks the threat from global warming warrants costly public-policy remedies. And of course, even though Lindzen is an accomplished climate scientist, he has his own political outlook—a conservative one.
He wasn’t reared that way. “Growing up in the Bronx, politics, I would say, was an automatic issue. I grew up with a picture of Franklin Roosevelt over my bed.” But his views started to shift in the late ’60s and ’70s. “I think [my politics] began changing in the Vietnam war. I was deeply disturbed by the way vets were being treated,” he says. He also says that his experience in the climate debate—and the rise in political correctness in the universities throughout the ’70s and ’80s—further pushed him to the right. So, yes, Lindzen, a climate skeptic, is also a political conservative whom one would expect to oppose many environmental regulations for ideological, as opposed to scientific, reasons.
By the same token, it is well known that the vast majority of “alarmist” climate scientists, dependent as they are on federal largesse, are liberal Democrats.
But whatever buried ideological component there may be to any given scientist’s work, it doesn’t tell us who has the science right. In a 2012 public letter, Lindzen noted, “Critics accuse me of doing a disservice to the scientific method. I would suggest that in questioning the views of the critics and subjecting them to specific tests, I am holding to the scientific method.” Whoever is right about computer models, climate sensitivity, aerosols, and water vapor, Lindzen is certainly right about that. Skepticism is essential to science.
In a 2007 debate with Lindzen in New York City, climate scientist Richard C. J. Somerville, who is firmly in the “alarmist” camp, likened climate skeptics to “some eminent earth scientists [who] couldn’t be persuaded that plate tectonics were real . . . when the revolution of continental drift was sweeping through geology and geophysics.”
“Most people who think they’re a Galileo are just wrong,” he said, much to the delight of a friendly audience of Manhattanites.
But Somerville botched the analogy. The story of plate tectonics is the story of how one man, Alfred Wegener, came up with the theory of continental drift, only to be widely opposed and mocked. Wegener challenged the earth science “consensus” of his day. And in the end, his view prevailed.
Ethan Epstein is an assistant editor at The Weekly Standard
Northern hemisphere temperature reconstructions for the past 2,000 years.
The Medieval Warm Period (MWP), Medieval Climate Optimum, or Medieval Climatic Anomaly was a time of warm climate in the North Atlantic region that may also have been related to other climate events around the world during that time, including in China[1] and other countries,[2][3][3][4][5][6][7] lasting from about AD 950 to 1250.[8] It was followed by a cooler period in the North Atlantic termed the Little Ice Age. Some refer to the event as the Medieval Climatic Anomaly as this term emphasizes that effects other than temperature were important.[9][10]
Despite substantial uncertainties, especially for the period prior to 1600 for which data are scarce, the warmest period of the last 2,000 years prior to the 20th century very likely occurred between 950 and 1100, but temperatures were probably between 0.1 °C and 0.2 °C below the 1961 to 1990 mean and significantly below the level shown by instrumental data after 1980. Proxy records from different regions show peak warmth at different times during the Medieval Warm Period, indicating the heterogeneous nature of climate at the time.[11] Temperatures in some regions matched or exceeded recent temperatures in these regions, but globally the Medieval Warm Period was cooler than recent global temperatures.[8]
Initial research
The Medieval Warm Period (MWP) is generally thought to have occurred from about AD 950–1250, during the EuropeanMiddle Ages.[8] In 1965 Hubert Lamb, one of the first paleoclimatologists, published research based on data from botany, historical document research and meteorology combined with records indicating prevailing temperature and rainfall in England around 1200 and around 1600. He proposed that "Evidence has been accumulating in many fields of investigation pointing to a notably warm climate in many parts of the world, that lasted a few centuries around A.D. 1000–1200, and was followed by a decline of temperature levels till between 1500 and 1700 the coldest phase since the last ice age occurred."[12]
The warm period became known as the MWP, and the cold period was called the Little Ice Age (LIA). However, this view was questioned by other researchers; the IPCC First Assessment Report of 1990 discussed the "Medieval Warm Period around 1000 AD (which may not have been global) and the Little Ice Age which ended only in the middle to late nineteenth century."[13] The IPCC Third Assessment Report from 2001 summarised research at that time, saying "…current evidence does not support globally synchronous periods of anomalous cold or warmth over this time frame, and the conventional terms of 'Little Ice Age' and 'Medieval Warm Period' appear to have limited utility in describing trends in hemispheric or global mean temperature changes in past centuries".[14] Global temperature records taken from ice cores, tree rings, and lake deposits, have shown that, taken globally, the Earth may have been slightly cooler (by 0.03 degrees Celsius) during the 'Medieval Warm Period' than in the early and mid-20th century.[15][16]
Palaeoclimatologists developing region-specific climate reconstructions of past centuries conventionally label their coldest interval as "LIA" and their warmest interval as the "MWP".[15][17] Others follow the convention and when a significant climate event is found in the "LIA" or "MWP" time frames, associate their events to the period. Some "MWP" events are thus wet events or cold events rather than strictly warm events, particularly in central Antarctica where climate patterns opposite to the North Atlantic area have been noticed.
By world region
Evidence exists across the world, often very sparsely, for changes in climatic conditions over time. Some of the "warm period" events documented below are actually "dry periods" or "wet periods."[18]
Globally
A 2009 study by Michael Mannet al. examining spatial patterns of surface temperatures shown in multi-proxy reconstructions finds that the MWP shows "warmth that matches or exceeds that of the past decade in some regions, but which falls well below recent levels globally."[8] Their reconstruction of MWP pattern is characterised by warmth over large part of North Atlantic, Southern Greenland, the Eurasian Arctic, and parts of North America which appears to substantially exceed that of the late 20th century (1961–1990) baseline and is comparable or exceeds that of the past one-to-two decades in some regions. Certain regions such as central Eurasia, northwestern North America, and (with less confidence) parts of the South Atlantic, exhibit anomalous coolness.
The last written records of the Norse Greenlanders are from a 1408 marriage in the church of Hvalsey — today the best-preserved of the Norse ruins.
A radiocarbon-dated box core in the Sargasso Sea shows that the sea surface temperature was approximately 1 °C (1.8 °F) cooler than today approximately 400 years ago (the Little Ice Age) and 1700 years ago, and approximately 1 °C warmer than today 1000 years ago (the Medieval Warm Period).[5]
Using sediment samples from Puerto Rico, the Gulf Coast and the Atlantic Coast from Florida to New England, Mann et al. (2009) found consistent evidence of a peak in North Atlantic tropical cyclone activity during the Medieval Warm Period followed by a subsequent lull in activity.[19]
Through retrieval and isotope analysis of marine cores and examination of mollusc growth patterns from Iceland, Patterson et al were able to reconstruct a mollusc growth record at a decadal resolution from the Roman Warm Period through the Medieval Warm Period and into the Little Ice Age.[20]
North America
1690 copy of the 1570 Skálholt map, based on documentary information about earlier Norse sites in America.
The 2009 Mann et al. study found warmth exceeding 1961–1990 levels in Southern Greenland and parts of North America during the Medieval climate anomaly (defined for this purpose as 950 to 1250) with warmth in some regions exceeding temperatures of the 1990–2010 period. Much of the Northern hemisphere showed significant cooling during the Little Ice Age (defined for the purpose as 1400 to 1700) but Labrador and isolated parts of the United States appeared to be approximately as warm as during the 1961–1990 period.[8]
Norse colonization of the Americas has been associated with warmer periods. The Vikings took advantage of ice-free seas to colonize areas in Greenland and other outlying lands of the far north.[21]
From around 1,000 AD Vikings formed settlements in two areas located near the southern tip of Greenland at a similar latitude to Iceland, the Eastern Settlement at the southern tip, and the Western Settlement to its north. A smaller group of farms between them has been identified by archaeologists as the "Middle Settlement". At that time they farmed cattle and pigs, with around a quarter of their diet from seafood, but after the climate became colder and stormier around 1250 smaller farms gradually changed to farming sheep and goats rather than cows. Around 1300 they abandoned pig farming, and from then on seal hunting provided over three quarters of their food. While there are no signs that this adversely affected their health, by mid century trade with Norway fell away and there was little demand for their exports of seal skins and walrus tusks. One of the last documents of their occupation dates from 1408, and over the remainder of that century the remaining Vikings left in what seems to have been an orderly withdrawal, largely due to social factors such as increased availability of farms in Scandinavian countries.[22]
Around 1000AD the climate was sufficiently warm for the north of Newfoundland to support a Viking colony and led to the descriptor "Vinland." An extensive settlement at L'Anse aux Meadows was found and originally excavated by Helge Ingstad.[23]
In the Chesapeake Bay, researchers found large temperature excursions (changes from the mean temperature of that time) during the Medieval Warm Period (about 950–1250) and the Little Ice Age (about 1400–1700, with cold periods persisting into the early 20th century), possibly related to changes in the strength of North Atlantic thermohaline circulation.[24] Sediments in Piermont Marsh of the lower Hudson Valley show a dry Medieval Warm period from AD 800–1300.[25]
Prolonged droughts affected many parts of the western United States and especially eastern California and the west of Great Basin.[15][26]Alaska experienced three time intervals of comparable warmth: AD 1–300, 850–1200, and post-1800.[27] Knowledge of the North American Medieval Warm Period has been useful in dating occupancy periods of certain Native American habitation sites, especially in arid parts of the western U.S.[28][29] Review of more recent archaeological research shows that as the search for signs of unusual cultural changes during the MWP has broadened, some of these early patterns (for example, violence and health problems) have been found to be more complicated and regionally varied than previously thought while others (for example, settlement disruption, deterioration of long distance trade, and population movements) have been further corroborated.[30]
Other regions
The climate in equatorial east Africa has alternated between drier than today, and relatively wet. The drier climate took place during the Medieval Warm Period (~AD 1000–1270).[31]
A sediment core from the eastern Bransfield Basin, Antarctic Peninsula, preserves climatic events in the Little Ice Age and Medieval Warm Period.[32] The core shows a distinctly cold period about AD 1000–1100, illustrating that during the "warm" period there were, regionally, periods of both warmth and cold.
Corals in the tropical Pacific Ocean suggest that relatively cool, dry conditions may have persisted early in the millennium, consistent with a La Niña-like configuration of the El Niño-Southern Oscillation patterns.[33] Although there is an extreme scarcity of data from Australia (for both the Medieval Warm Period and Little Ice Age) evidence from wave-built shingle terraces for a permanently full Lake Eyre[34] during the 9th and 10th centuries is consistent with this La Niña-like configuration, though of itself inadequate to show how lake levels varied from year to year or what climatic conditions elsewhere in Australia were like.
The MWP has been noted in Chile in a 1500-year lake bed sediment core,[35] as well as in the Eastern Cordillera of Ecuador.[36]
Adhikari and Kumon (2001), whilst investigating sediments in Lake Nakatsuna in central Japan, finding a warm period from AD 900 to 1200 that corresponded to the Medieval Warm Period and three cool phases, of which two could be related to the Little Ice Age.[37] Another research in northeastern Japan shows that there is one warm/humid interval from AD 750 to 1200, and two cold/dry intervals from AD 1 to 750 and 1200 to present.[7] Ge et al. studied temperatures in China during the past 2000 years; they found high uncertainty prior to the 16th century but good consistency over the last 500 years, highlighted by the two cold periods 1620s–1710s and 1800s–1860s, and the warming during the 20th century. They also found that the warming during the 10–14th centuries in some regions might be comparable in magnitude to the warming of the last few decades of the 20th century which was unprecedented within the past 500 years.[38]
A 1979 study from the University of Waikato found that "Temperatures derived from an 18O/16O profile through a stalagmite found in a New Zealand cave (40.67°S, 172.43°E) suggested the Medieval Warm Period to have occurred between AD 1050 and 1400 and to have been 0.75 °C warmer than the Current Warm Period."[39] The MWP has also been evidenced in New Zealand by an 1100-year tree-ring record.[40]
A reconstruction based on ice cores found the Medieval Warm Period could be distinguished in tropical South America from about 1050 to 1300, followed in the 15th century by the Little Ice Age. Peak temperatures did not rise as high as those from the late 20th century, which were unprecedented in the area during the study period going back around 1600 years.[41]
There are approximately 86 billion neurons in the human brain. Over the past decades, we have made enormous progress in understanding their molecular, genetic, and structural makeup as well as their function. However, the real power of the central nervous system lies in the smooth coordination of large numbers of neurons. Neurons are thus organized on many different scales, from small microcircuits and assemblies all the way to regional brain networks. To interact effectively on all these levels, neurons, nuclei, cortical columns, and larger areas need to be connected. The study of neuronal connectivity has expanded rapidly in past years. Large research groups have recently joined forces and formed consortia to tackle the difficult problems of how to experimentally investigate connections in the brain and how to analyze and make sense of the enormous amount of data that arises in the process.
This year's neuroscience special issue is devoted to general and also several more specific aspects of research on connectivity in the brain. We invited researchers to review the most recent progress in their fields and to provide us with an outlook on what the future may hold in store.
To make sense of larger structures, we first have to understand the composition of their basic building blocks. Markov et al. (p. 578) describe how interareal connectivity at the single-cell level, revealed by quantitative anatomical tract tracing, is relevant to our understanding of large-scale cortical networks and their hierarchical organization.
A different but also rapidly growing research direction deals with the use of connectivity measures to link brain structure and cognition. From the perspective of network theory, Park and Friston (p. 579) review our current understanding of structure-function relationships in large-scale brain networks and their underlying mechanisms.
One of the biggest breakthroughs in understanding the heavily connected brain has been the development of noninvasive brain-scanning methods, especially functional magnetic resonance imaging (fMRI). Turk-Browne (p. 580) provides an overview of recent exciting developments in large-scale fMRI data analysis, with a focus on unbiased approaches for examining whole-brain functional connectivity during cognitive tasks. Increased computational power now allows investigation of the whole-brain correlation matrix, the temporal correlation of every voxel with every other voxel throughout the brain, and the application of multivariate pattern analysis to these correlational data.
A sophisticated system that depends on the astonishingly precise interaction of a large number of cortical areas is the human ability to produce and understand language and music. Zatorre (p. 585) discusses how brain plasticity in the music and speech domains can be affected by predisposing factors that relate to brain structure and function.
Much of what medical researchers conclude in their studies is misleading, exaggerated, or flat-out wrong. So why are doctors—to a striking extent—still drawing upon misinformation in their everyday practice? Dr. John Ioannidis has spent his career challenging his peers by exposing their bad science.
In 2001, rumors were circulating in Greek hospitals that surgery residents, eager to rack up scalpel time, were falsely diagnosing hapless Albanian immigrants with appendicitis. At the University of Ioannina medical school’s teaching hospital, a newly minted doctor named Athina Tatsioni was discussing the rumors with colleagues when a professor who had overheard asked her if she’d like to try to prove whether they were true—he seemed to be almost daring her. She accepted the challenge and, with the professor’s and other colleagues’ help, eventually produced a formal study showing that, for whatever reason, the appendices removed from patients with Albanian names in six Greek hospitals were more than three times as likely to be perfectly healthy as those removed from patients with Greek names. “It was hard to find a journal willing to publish it, but we did,” recalls Tatsioni. “I also discovered that I really liked research.” Good thing, because the study had actually been a sort of audition. The professor, it turned out, had been putting together a team of exceptionally brash and curious young clinicians and Ph.D.s to join him in tackling an unusual and controversial agenda.
Last spring, I sat in on one of the team’s weekly meetings on the medical school’s campus, which is plunked crazily across a series of sharp hills. The building in which we met, like most at the school, had the look of a barracks and was festooned with political graffiti. But the group convened in a spacious conference room that would have been at home at a Silicon Valley start-up. Sprawled around a large table were Tatsioni and eight other youngish Greek researchers and physicians who, in contrast to the pasty younger staff frequently seen in U.S. hospitals, looked like the casually glamorous cast of a television medical drama. The professor, a dapper and soft-spoken man named John Ioannidis, loosely presided.
One of the researchers, a biostatistician named Georgia Salanti, fired up a laptop and projector and started to take the group through a study she and a few colleagues were completing that asked this question: were drug companies manipulating published research to make their drugs look good? Salanti ticked off data that seemed to indicate they were, but the other team members almost immediately started interrupting. One noted that Salanti’s study didn’t address the fact that drug-company research wasn’t measuring critically important “hard” outcomes for patients, such as survival versus death, and instead tended to measure “softer” outcomes, such as self-reported symptoms (“my chest doesn’t hurt as much today”). Another pointed out that Salanti’s study ignored the fact that when drug-company data seemed to show patients’ health improving, the data often failed to show that the drug was responsible, or that the improvement was more than marginal.
Salanti remained poised, as if the grilling were par for the course, and gamely acknowledged that the suggestions were all good—but a single study can’t prove everything, she said. Just as I was getting the sense that the data in drug studies were endlessly malleable, Ioannidis, who had mostly been listening, delivered what felt like a coup de grâce: wasn’t it possible, he asked, that drug companies were carefully selecting the topics of their studies—for example, comparing their new drugs against those already known to be inferior to others on the market—so that they were ahead of the game even before the data juggling began? “Maybe sometimes it’s the questions that are biased, not the answers,” he said, flashing a friendly smile. Everyone nodded. Though the results of drug studies often make newspaper headlines, you have to wonder whether they prove anything at all. Indeed, given the breadth of the potential problems raised at the meeting, can any medical-research studies be trusted?
That question has been central to Ioannidis’s career. He’s what’s known as a meta-researcher, and he’s become one of the world’s foremost experts on the credibility of medical research. He and his team have shown, again and again, and in many different ways, that much of what biomedical researchers conclude in published studies—conclusions that doctors keep in mind when they prescribe antibiotics or blood-pressure medication, or when they advise us to consume more fiber or less meat, or when they recommend surgery for heart disease or back pain—is misleading, exaggerated, and often flat-out wrong. He charges that as much as 90 percent of the published medical information that doctors rely on is flawed. His work has been widely accepted by the medical community; it has been published in the field’s top journals, where it is heavily cited; and he is a big draw at conferences. Given this exposure, and the fact that his work broadly targets everyone else’s work in medicine, as well as everything that physicians do and all the health advice we get, Ioannidis may be one of the most influential scientists alive. Yet for all his influence, he worries that the field of medical research is so pervasively flawed, and so riddled with conflicts of interest, that it might be chronically resistant to change—or even to publicly admitting that there’s a problem.
The city of Ioannina is a big college town a short drive from the ruins of a 20,000-seat amphitheater and a Zeusian sanctuary built at the site of the Dodona oracle. The oracle was said to have issued pronouncements to priests through the rustling of a sacred oak tree. Today, a different oak tree at the site provides visitors with a chance to try their own hands at extracting a prophecy. “I take all the researchers who visit me here, and almost every single one of them asks the tree the same question,” Ioannidis tells me, as we contemplate the tree the day after the team’s meeting. “‘Will my research grant be approved?’” He chuckles, but Ioannidis (pronounced yo-NEE-dees) tends to laugh not so much in mirth as to soften the sting of his attack. And sure enough, he goes on to suggest that an obsession with winning funding has gone a long way toward weakening the reliability of medical research.
He first stumbled on the sorts of problems plaguing the field, he explains, as a young physician-researcher in the early 1990s at Harvard. At the time, he was interested in diagnosing rare diseases, for which a lack of case data can leave doctors with little to go on other than intuition and rules of thumb. But he noticed that doctors seemed to proceed in much the same manner even when it came to cancer, heart disease, and other common ailments. Where were the hard data that would back up their treatment decisions? There was plenty of published research, but much of it was remarkably unscientific, based largely on observations of a small number of cases. A new “evidence-based medicine” movement was just starting to gather force, and Ioannidis decided to throw himself into it, working first with prominent researchers at Tufts University and then taking positions at Johns Hopkins University and the National Institutes of Health. He was unusually well armed: he had been a math prodigy of near-celebrity status in high school in Greece, and had followed his parents, who were both physician-researchers, into medicine. Now he’d have a chance to combine math and medicine by applying rigorous statistical analysis to what seemed a surprisingly sloppy field. “I assumed that everything we physicians did was basically right, but now I was going to help verify it,” he says. “All we’d have to do was systematically review the evidence, trust what it told us, and then everything would be perfect.”
It didn’t turn out that way. In poring over medical journals, he was struck by how many findings of all types were refuted by later findings. Of course, medical-science “never minds” are hardly secret.
And they sometimes make headlines, as when in recent years large studies or growing consensuses of researchers concluded that mammograms, colonoscopies, and PSA tests are far less useful cancer-detection tools than we had been told; or when widely prescribed antidepressants such as Prozac, Zoloft, and Paxil were revealed to be no more effective than a placebo for most cases of depression; or when we learned that staying out of the sun entirely can actually increase cancer risks; or when we were told that the advice to drink lots of water during intense exercise was potentially fatal; or when, last April, we were informed that taking fish oil, exercising, and doing puzzles doesn’t really help fend off Alzheimer’s disease, as long claimed. Peer-reviewed studies have come to opposite conclusions on whether using cell phones can cause brain cancer, whether sleeping more than eight hours a night is healthful or dangerous, whether taking aspirin every day is more likely to save your life or cut it short, and whether routine angioplasty works better than pills to unclog heart arteries.
But beyond the headlines, Ioannidis was shocked at the range and reach of the reversals he was seeing in everyday medical research. “Randomized controlled trials,” which compare how one group responds to a treatment against how an identical group fares without the treatment, had long been considered nearly unshakable evidence, but they, too, ended up being wrong some of the time. “I realized even our gold-standard research had a lot of problems,” he says. Baffled, he started looking for the specific ways in which studies were going wrong. And before long he discovered that the range of errors being committed was astonishing: from what questions researchers posed, to how they set up the studies, to which patients they recruited for the studies, to which measurements they took, to how they analyzed the data, to how they presented their results, to how particular studies came to be published in medical journals.
This array suggested a bigger, underlying dysfunction, and Ioannidis thought he knew what it was.
“The studies were biased,” he says. “Sometimes they were overtly biased. Sometimes it was difficult to see the bias, but it was there.” Researchers headed into their studies wanting certain results—and, lo and behold, they were getting them. We think of the scientific process as being objective, rigorous, and even ruthless in separating out what is true from what we merely wish to be true, but in fact it’s easy to manipulate results, even unintentionally or unconsciously. “At every step in the process, there is room to distort results, a way to make a stronger claim or to select what is going to be concluded,” says Ioannidis. “There is an intellectual conflict of interest that pressures researchers to find whatever it is that is most likely to get them funded.”
Perhaps only a minority of researchers were succumbing to this bias, but their distorted findings were having an outsize effect on published research. To get funding and tenured positions, and often merely to stay afloat, researchers have to get their work published in well-regarded journals, where rejection rates can climb above 90 percent. Not surprisingly, the studies that tend to make the grade are those with eye-catching findings. But while coming up with eye-catching theories is relatively easy, getting reality to bear them out is another matter. The great majority collapse under the weight of contradictory data when studied rigorously. Imagine, though, that five different research teams test an interesting theory that’s making the rounds, and four of the groups correctly prove the idea false, while the one less cautious group incorrectly “proves” it true through some combination of error, fluke, and clever selection of data. Guess whose findings your doctor ends up reading about in the journal, and you end up hearing about on the evening news? Researchers can sometimes win attention by refuting a prominent finding, which can help to at least raise doubts about results, but in general it is far more rewarding to add a new insight or exciting-sounding twist to existing research than to retest its basic premises—after all, simply re-proving someone else’s results is unlikely to get you published, and attempting to undermine the work of respected colleagues can have ugly professional repercussions.
In the late 1990s, Ioannidis set up a base at the University of Ioannina. He pulled together his team, which remains largely intact today, and started chipping away at the problem in a series of papers that pointed out specific ways certain studies were getting misleading results. Other meta-researchers were also starting to spotlight disturbingly high rates of error in the medical literature. But Ioannidis wanted to get the big picture across, and to do so with solid data, clear reasoning, and good statistical analysis. The project dragged on, until finally he retreated to the tiny island of Sikinos in the Aegean Sea, where he drew inspiration from the relatively primitive surroundings and the intellectual traditions they recalled. “A pervasive theme of ancient Greek literature is that you need to pursue the truth, no matter what the truth might be,” he says. In 2005, he unleashed two papers that challenged the foundations of medical research.
He chose to publish one paper, fittingly, in the online journal PLoS Medicine, which is committed to running any methodologically sound article without regard to how “interesting” the results may be. In the paper, Ioannidis laid out a detailed mathematical proof that, assuming modest levels of researcher bias, typically imperfect research techniques, and the well-known tendency to focus on exciting rather than highly plausible theories, researchers will come up with wrong findings most of the time.
Simply put, if you’re attracted to ideas that have a good chance of being wrong, and if you’re motivated to prove them right, and if you have a little wiggle room in how you assemble the evidence, you’ll probably succeed in proving wrong theories right. His model predicted, in different fields of medical research, rates of wrongness roughly corresponding to the observed rates at which findings were later convincingly refuted: 80 percent of non-randomized studies (by far the most common type) turn out to be wrong, as do 25 percent of supposedly gold-standard randomized trials, and as much as 10 percent of the platinum-standard large randomized trials. The article spelled out his belief that researchers were frequently manipulating data analyses, chasing career-advancing findings rather than good science, and even using the peer-review process—in which journals ask researchers to help decide which studies to publish—to suppress opposing views. “You can question some of the details of John’s calculations, but it’s hard to argue that the essential ideas aren’t absolutely correct,” says Doug Altman, an Oxford University researcher who directs the Centre for Statistics in Medicine.
Still, Ioannidis anticipated that the community might shrug off his findings: sure, a lot of dubious research makes it into journals, but we researchers and physicians know to ignore it and focus on the good stuff, so what’s the big deal? The other paper headed off that claim. He zoomed in on 49 of the most highly regarded research findings in medicine over the previous 13 years, as judged by the science community’s two standard measures: the papers had appeared in the journals most widely cited in research articles, and the 49 articles themselves were the most widely cited articles in these journals. These were articles that helped lead to the widespread popularity of treatments such as the use of hormone-replacement therapy for menopausal women, vitamin E to reduce the risk of heart disease, coronary stents to ward off heart attacks, and daily low-dose aspirin to control blood pressure and prevent heart attacks and strokes. Ioannidis was putting his contentions to the test not against run-of-the-mill research, or even merely well-accepted research, but against the absolute tip of the research pyramid. Of the 49 articles, 45 claimed to have uncovered effective interventions. Thirty-four of these claims had been retested, and 14 of these, or 41 percent, had been convincingly shown to be wrong or significantly exaggerated. If between a third and a half of the most acclaimed research in medicine was proving untrustworthy, the scope and impact of the problem were undeniable. That article was published in the Journal of the American Medical Association.
Driving me back to campus in his smallish SUV—after insisting, as he apparently does with all his visitors, on showing me a nearby lake and the six monasteries situated on an islet within it—Ioannidis apologized profusely for running a yellow light, explaining with a laugh that he didn’t trust the truck behind him to stop. Considering his willingness, even eagerness, to slap the face of the medical-research community, Ioannidis comes off as thoughtful, upbeat, and deeply civil. He’s a careful listener, and his frequent grin and semi-apologetic chuckle can make the sharp prodding of his arguments seem almost good-natured. He is as quick, if not quicker, to question his own motives and competence as anyone else’s. A neat and compact 45-year-old with a trim mustache, he presents as a sort of dashing nerd—Giancarlo Giannini with a bit of Mr. Bean.
The humility and graciousness seem to serve him well in getting across a message that is not easy to digest or, for that matter, believe: that even highly regarded researchers at prestigious institutions sometimes churn out attention-grabbing findings rather than findings likely to be right. But Ioannidis points out that obviously questionable findings cram the pages of top medical journals, not to mention the morning headlines. Consider, he says, the endless stream of results from nutritional studies in which researchers follow thousands of people for some number of years, tracking what they eat and what supplements they take, and how their health changes over the course of the study.
“Then the researchers start asking, ‘What did vitamin E do? What did vitamin C or D or A do? What changed with calorie intake, or protein or fat intake? What happened to cholesterol levels? Who got what type of cancer?’” he says. “They run everything through the mill, one at a time, and they start finding associations, and eventually conclude that vitamin X lowers the risk of cancer Y, or this food helps with the risk of that disease.” In a single week this fall, Google’s news page offered these headlines: “More Omega-3 Fats Didn’t Aid Heart Patients”; “Fruits, Vegetables Cut Cancer Risk for Smokers”; “Soy May Ease Sleep Problems in Older Women”; and dozens of similar stories.
