Do 97% of climate scientists agree we're causing global warming?

‘But aren’t 97 per cent of climate scientists sure that humans are causing global warming?’

By Don Aitkin
Posted Friday, 22 April 2016

One of the most frequently used rhetorical devices to avoid answering the questions of the critics of the AGC scare is the proposition that there is a astonishing scientific ‘consensus’ on the point: some 97 per cent of climate scientists are said to agree. By implication, the other 3 per cent are simply ignorant, mavericks or troublemakers, to be lumped in with other people who fall into the category ‘climate deniers’. We are thus asked to accept the authority of the consensus, and to cease and desist from questioning anything about global warming or ‘climate change’.

To deal with this part of the debate we need to go back to the beginning. The AGW scare is built around three core propositions: that the earth is warming, that the warming is caused by human activities, especially the burning of fossil fuels, and that the warming is dangerous. It is said, or implied, that 97 per cent of ‘climate scientists’ agree with this triad. In fact President Obama’s office tweeted exactly this statement in 2015: Ninety-seven percent of scientists agree: #climate change is real, man-made and dangerous.

Science is rarely a matter of consensus, and where it is so what we are usually talking about is the material that goes into textbooks, for beginning students need to have some understanding of what is generally agreed to be the case (some of what I learned in high school science is now generally agreed to be wrong or irrelevant). As students get to be more senior, they are exposed to argument, and taught to explore and test the hypotheses and evidence that lie behind what has been published. In experimental science, consensus is simply current opinion, and it can be quite wrong. As Einstein said, when a group of scientists in 1931 published a book Hundert Autoren gegen Einstein (‘One hundred authors against Einstein’), ‘Why one hundred? If I were wrong, then one would be enough!’ That one would have conducted the experiment whose results showed conclusively that Einstein’s hypothesis must be wrong, but none of the hundred had done that. They were simply expressing their separate opinions.

Now, what do ‘climate scientists’ actually say? I’ve put inverted commas around the term because there is no agreed meaning for it. Most of the leading figures in this sub-field have degrees in other disciplines, whatever the title of their current chair. The ’97 per cent’ figure is supported by three different published articles, with a forerunner by Naomi Oreskes, about whom I wrote a little while ago. In 2004 she looked at 928 abstracts of articles in the climate science field. According to her, 75 per cent supported the view that human activities were responsible for most of the warming in the last fifty years. Now we should stop for a moment to observe that the scientists themselves had said nothing. She had not interviewed them. Instead, she had looked at the abstracts of their articles, and come to a view about what their authors must have thought. Why those 928? Well, they were the papers in the ISI database from 1993 to 2003 that had the words ‘climate change’ as a tag. Ms Oreskes seemed somehow to have excluded articles by scientists such as Christy, Lindzen, Michaels and Idso, all of them sceptics, and somewhat to their surprise. What was the method of evaluation? She divided the papers into six groups and found that 75 per cent of them either explicitly or implicitly accepted the ‘consensus view’. What was that? In her words: the evidence for human modification of climate is compelling. Is that a bad thing? That seems not to have been part of her survey, but one might infer that for her the outcome must be bad. You’ll have noticed that she looked only at abstracts, and did not read the full articles in question.

We move on. In 2009 Zimmerman and Doran asked scientists two questions: did they think that temperatures had risen and whether humans were significantly responsible. Again, no mention of dangerous consequences, but at least the authors did actually ask some scientists what they thought. But then the methodology gets very sloppy, and I’ll summarise it like this. They used an online survey of 10,257 members of the American Geophysical Union, whose membership is around 60,000. The respondents seemed to be the right ones to interview, given their fields of interest, but only 3,146 actually replied. Now they excluded nearly all of those who had replied, for one reason and another, to produce 79 scientists who said they were climate scientists and had published more than half of their work on ‘climate change’. Of them 77 both thought that temperatures had risen and that humans were significantly responsible. The fraction 77/79 gives you 97 per cent, and I think that’s the first occasion the figure came up. Consensus had been found! I say no more. Some methodology is just so bad you can’t credit that a responsible journal would publish it. Alas, even worse is to come.

A year later Anderegg et al explored the work of 200 of the most prolific writers on ‘climate change’ and argued that 97% to 98% of the 200 most prolific writers on climate change believe “anthropogenic greenhouse gases have been responsible for ‘most’ of the ‘unequivocal’ warming.” So they too got a 97 per cent figure. Again, no mention of any danger from warming. Again, no one was asked anything. The authors started with 1372 scientists whom they assessed to be the leading ones in the field, and winnowed them down to 200 of the really top. Then they just read, and made a decision from their reading. The 97 per cent were well published and agreed with the orthodox position; the 3 per cent were well published and did not agree.

The crème de la crème  comes with the work (if that is right term for it) of John Cook, occasionally aided by Stefan Lewandowsky. I’ve written about their ‘contribution’ to science more than once. In 2013 Cook et al and a team of volunteers looked at more than 12,000 abstracts, rated them according to whether or not they implicitly or explicitly endorsed the view that human activity had caused (wait for it) some of the warming, and again found the magic 97 per cent. See — it’s true! Surely those three separate ratings of 97 per cent have something going for them.

On the face of it, no. Unfortunately for Cook, Legates and others later in the same year published a rebuttal. They found that only 41 papers – 0.3% of all 11,944 abstracts or 1.0% of the 4,014 expressing an opinion, and not 97.1% – had been found to endorse the claim that human activity is causing most of the current warming. Elsewhere, Craig Idso, Nicola Scafetta, Nir J. Shaviv and Nils-Axel Morner and other climate scientists protested that Mr. Cook ignored or misrepresented their work. Cook has been trying to defend his results ever since, but more and more scorn has, in my view quite rightly, been poured on the work. As I have said before, this is terrible stuff methodologically, the worst I’ve ever seen in a peer-reviewed journal.

Let’s summarise. Point one: none of these papers asked whether or not AGW was dangerous to humanity or anything else. So none of them is evidence for the Obama tweet set out at the beginning of this essay. As a self-styled lukewarmer, I have no difficulty in nodding about propositions that the earth has warmed over the last 150 years, or that human activity has made some contribution to that warming. With the evidence available, it seems to me unlikely that the human contribution has been crucial, for two reasons. First, there was a decided hiatus over 18 years, when global temperature anomalies went up and down with little average change, while carbon dioxide accumulations kept on rising steadily. The end of the hiatus came not with a burst of CO2, but with a powerful el Nino, already subsiding quickly. Second, there are plainly other factors at work, and if they were at work in the past, why are they not generally at work?

Point two: the belief that global warming is bad for everything and everyone comes from two notions. The first is that simple linear extrapolations from the period 1975 to 1998 made it  look as though warming would go on and on, and that was the fear at the end of the 20th century. As we know, that didn’t happen. Second, the GCMs on which the IPCC based its projections or scenarios for the 21st century tell us that it must happen, in part because they are built on the notion that carbon dioxide accumulations must rise and rise, and bring on large increases of temperature caused by the notion of strongly positive climate sensitivity. I dealt with that in the #7 essay.

If there is anything like a consensus, given what I have read over the past ten years, it would be around the lukewarm position: the planet is warmer than it was 150 years ago, though not in an unprecedented way, and that human activity in burning fossil fuels, clearing land and making cement has had something to do with that warming. More than that is simply contestable, and more contestable now than it was thirty years ago.

And that people keep referring to the magic 97 per cent figure, as though it means something, is to me a sign of a closed mind and a quasi-religious belief in the scare. Such people seem to me intellectually lost souls.

Don Aitkin has been an academic and vice-chancellor. His latest book, published in 2015, is Turning Point, the second novel in The Hogarth Trilogy.

This article was published on Don Aitkin's blog site and in On Line Opinion.

Why Americans Hate Soccer

AMERICA'S FAVORITE NATIONAL PASTIME: HATING SOCCER

June 25, 2014

I've held off on writing about soccer for a decade -- or about the length of the average soccer game -- so as not to offend anyone. But enough is enough. Any growing interest in soccer can only be a sign of the nation's moral decay.

(1) Individual achievement is not a big factor in soccer. In a real sport, players fumble passes, throw bricks and drop fly balls -- all in front of a crowd. When baseball players strike out, they're standing alone at the plate. But there's also individual glory in home runs, touchdowns and slam-dunks.

In soccer, the blame is dispersed and almost no one scores anyway. There are no heroes, no losers, no accountability, and no child's fragile self-esteem is bruised. There's a reason perpetually alarmed women are called "soccer moms," not "football moms."

Do they even have MVPs in soccer? Everyone just runs up and down the field and, every once in a while, a ball accidentally goes in. That's when we're supposed to go wild. I'm already asleep.

(2) Liberal moms like soccer because it's a sport in which athletic talent finds so little expression that girls can play with boys. No serious sport is co-ed, even at the kindergarten level.

(3) No other "sport" ends in as many scoreless ties as soccer. This was an actual marquee sign by the freeway in Long Beach, California, about a World Cup game last week: "2nd period, 11 minutes left, score: 0:0." Two hours later, another World Cup game was on the same screen: "1st period, 8 minutes left, score: 0:0." If Michael Jackson had treated his chronic insomnia with a tape of Argentina vs. Brazil instead of Propofol, he'd still be alive, although bored.

Even in football, by which I mean football, there are very few scoreless ties -- and it's a lot harder to score when a half-dozen 300-pound bruisers are trying to crush you.

(4) The prospect of either personal humiliation or major injury is required to count as a sport. Most sports are sublimated warfare. As Lady Thatcher reportedly said after Germany had beaten England in some major soccer game: Don't worry. After all, twice in this century we beat them at their national game.

Baseball and basketball present a constant threat of personal disgrace. In hockey, there are three or four fights a game -- and it's not a stroll on beach to be on ice with a puck flying around at 100 miles per hour. After a football game, ambulances carry off the wounded. After a soccer game, every player gets a ribbon and a juice box.

(5) You can't use your hands in soccer. (Thus eliminating the danger of having to catch a fly ball.) What sets man apart from the lesser beasts, besides a soul, is that we have opposable thumbs. Our hands can hold things. Here's a great idea: Let's create a game where you're not allowed to use them!

(6) I resent the force-fed aspect of soccer. The same people trying to push soccer on Americans are the ones demanding that we love HBO's "Girls," light-rail, Beyonce and Hillary Clinton. The number of New York Times articles claiming soccer is "catching on" is exceeded only by the ones pretending women's basketball is fascinating.
 

 I note that we don't have to be endlessly told how exciting football is.

(7) It's foreign. In fact, that's the precise reason the Times is constantly hectoring Americans to love soccer. One group of sports fans with whom soccer is not "catching on" at all, is African-Americans. They remain distinctly unimpressed by the fact that the French like it.

(8) Soccer is like the metric system, which liberals also adore because it's European. Naturally, the metric system emerged from the French Revolution, during the brief intervals when they weren't committing mass murder by guillotine.

Despite being subjected to Chinese-style brainwashing in the public schools to use centimeters and Celsius, ask any American for the temperature, and he'll say something like "70 degrees." Ask how far Boston is from New York City, he'll say it's about 200 miles.

Liberals get angry and tell us that the metric system is more "rational" than the measurements everyone understands. This is ridiculous. An inch is the width of a man's thumb, a foot the length of his foot, a yard the length of his belt. That's easy to visualize. How do you visualize 147.2 centimeters?

(9) Soccer is not "catching on." Headlines this week proclaimed "Record U.S. ratings for World Cup," and we had to hear -- again -- about the "growing popularity of soccer in the United States."

The USA-Portugal game was the blockbuster match, garnering 18.2 million viewers on ESPN. This beat the second-most watched soccer game ever: The 1999 Women's World Cup final (USA vs. China) on ABC. (In soccer, the women's games are as thrilling as the men's.)

Run-of-the-mill, regular-season Sunday Night Football games average more than 20 million viewers; NFL playoff games get 30 to 40 million viewers; and this year's Super Bowl had 111.5 million viewers.

Remember when the media tried to foist British soccer star David Beckham and his permanently camera-ready wife on us a few years ago? Their arrival in America was heralded with 24-7 news coverage. That lasted about two days. Ratings tanked. No one cared.

If more "Americans" are watching soccer today, it's only because of the demographic switch effected by Teddy Kennedy's 1965 immigration law. I promise you: No American whose great-grandfather was born here is watching soccer. One can only hope that, in addition to learning English, these new Americans will drop their soccer fetish with time.

COPYRIGHT 2014 ANN COULTER

Fatty food research results from 40 years ago contradict published recommendations

This study 40 years ago could have reshaped the American diet. But it was never fully published.

By Peter Whoriskey April 12

It was one of the largest, most rigorous experiments ever conducted on an important diet question: How do fatty foods affect our health? Yet it took more than 40 years - that is, until today - for a clear picture of the results to reach the public.

The fuller results appeared Tuesday in BMJ (British Medical Journal) featuring some never-before-published data. Collectively, the fuller results undermine the conventional wisdom regarding dietary fat that has persisted for decades and is still enshrined in influential publications such as the U.S. government's Dietary Guidelines for Americans.  But the long-belated saga of the Minnesota Coronary Experiment may also make a broader point about how science gets done: it suggests just how difficult it can be for new evidence to see the light of day when it contradicts widely held theories.

The story begins in the late 1960s and early ’70s, when researchers in Minnesota engaged thousands of institutionalized mental patients to compare the effects of two diets.  One group of patients was fed a diet intended to lower blood cholesterol and reduce heart disease. It contained less saturated fat, less cholesterol and more vegetable oil. The other group was fed a more typical American diet.

Just as researchers expected, the special diet reduced blood cholesterol in patients. And while the special diet didn’t seem to have any effect on heart disease, researchers said they suspected that a benefit would have appeared if the experiment had gone on longer.

There was “a favorable trend,” they wrote, for younger patients.

Today, the principles of that special diet — less saturated fat, more vegetable oils — are recommended by the Dietary Guidelines for Americans, the government’s official diet advice book. Yet the fuller accounting of the Minnesota data indicates that the advice is, at best, unsupported by the massive trial. In fact, it appears to show just the opposite:  Patients who lowered their cholesterol, presumably because of the special diet, actually suffered more heart-related deaths than those who did not.

The higher rate of mortality for patients on the special diet was most apparent among patients older than 64.

The blue line represents the mortality rate of patients on the special cholesterol-lowering diet. The dashed red line represents the mortality rate of patients on the conventional diet. The take-away: people on the special diet were dying at a higher rate. (Source: BMJ)

The new researchers, led by investigators from the National Institutes of Health and the University of North Carolina, conclude that the absence of the data over the past 40 years or so may have led to a misunderstanding of this key dietary issue.

“Incomplete publication has contributed to the overestimation of benefits and underestimation of potential risks” of the special diet, they wrote.

“Had this research been published 40 years ago, it might have changed the trajectory of diet-heart research and recommendations” said Daisy Zamora, a researcher at UNC and a lead author of the study.

The new research drew quick criticism, however, especially from experts who have been prominent in the campaign against saturated fats.

"The bottom line is that this report adds no useful new information and is irrelevant to current dietary recommendations that emphasize replacing saturated fat with polyunsaturated fat," Walter Willett, chair of the nutrition department at Harvard University, said in a blog post from the school. "Many lines of evidence support this conclusion."

He characterized the new analysis of the old experiment as "an interesting historical footnote."

The new research will agitate the debate over one of the most controversial questions in all of nutrition: Does the consumption of saturated fats - the ones characteristic of meat and dairy products  - contribute to heart disease?

It is, without doubt, an important question. Heart disease is the leading cause of mortality in the United States, and Americans eat a lot of red meat and dairy foods.

The federal government has long blamed saturated fats for health troubles, and it continues — through the Dietary Guidelines for Americans — to recommend that people limit their intake.

Indeed, the Dietary Guidelines continue to embrace the principles advocated by the Minnesota researchers from 40 years ago. The book advises Americans to limit their intake of saturated fats and to replace them at least in part with oils, just as the Minnesota experimenters did 40 years ago. More specifically, it advises Americans to consume about five teaspoons (27 grams) of oils per day, mentioning canola, corn, olive, peanut, safflower, soybean and sunflower oils.

“Oils should replace solid fats rather than being added to the diet,” it advises.

But the idea that spurning saturated fat will, by itself, make people healthier has never been fully proved, and in recent years repeated clinical trials and large-scale observational studies have produced evidence to the contrary. Whether cutting saturated fats out of your diet will make you healthier depends, of course, on what you replace them with.

“What this research implies is that there is not enough evidence to draw strong conclusions about the health effects of vegetable oils” Christopher Ramsden, a medical investigator at NIH and a lead author of the study, said in an interview. While urging caution in drawing conclusions about the new analysis, he said the research suggested saturated fats "may not be as bad as originally thought."

Ramsden and colleagues discovered the missing data during their research examining the potentially harmful effects of linoleic acid - a key constituent of most vegetable oils - on human health. Preliminary research suggests a link between linoleic acid and diseases such as chronic pain, Ramsden said, and humans have been consuming it in larger quantities than their bodies may be prepared for. Before the advent of agriculture, humans got 2 to 3 percent of their calories from linoleic acid, according to the new paper; today most Americans, awash in cooking oils and oils added to snack foods, get much more.

It's not exactly clear why the full set of data from the Minnesota experiment was never published.

As research efforts on diets go, the study was rigorous. Funded by the U.S. Public Health Service and the National Heart Institute, it involved more than 9,000 patients who were randomly assigned to one of the two diets.  Detailed measurements of blood cholesterol and other indexes of health were recorded.

Willett, the Harvard nutritionist, faulted the experiment because many of the patients were on the special diets for relatively brief periods - many were being released from the mental institutions. But about a quarter of the patients remained on the diet for a year or longer, and why such an apparently well-done study received so little fanfare is mystifying to some.

The results of the study were never touted by the investigators. Partial results were presented at an American Heart Association conference in 1975, and it wasn't until 1989 that some of the results were published, appearing in a medical journal known as Arteriosclerosis.

The lead investigators of the trial, noted scientists Ancel Keys and Ivan Frantz, are deceased.

Steven Broste, now a retired biostatistician, was then a student at the University of Minnesota and used the full set of data for his master's thesis in 1981. He interacted with the researchers. Part of the problem, Broste suggested in an interview, may have been limits on statistical methods at the time. Computer software for statistics wasn't as readily available as it is today. So, at the time of the study, it wasn't as easy to know how significant the data was. Broste completed his thesis several years after the last patients had left the trial, but it was not published in a journal.

Broste also suggested that at least part of the reason for the incomplete publication of the data might have been human nature. The Minnesota investigators had a theory that they believed in - that reducing blood cholesterol would make people healthier. Indeed, the idea was widespread and would soon be adopted by the federal government in the first dietary recommendations. So when the data they collected from the mental patients conflicted with this theory, the scientists may have been reluctant to believe what their experiment had turned up.

“The results flew in the face of what people believed at the time,” said Broste. “Everyone thought cholesterol was the culprit. This theory was so widely held and so firmly believed - and then it wasn’t borne out by the data. The question then became: Was it a bad theory? Or was it bad data? ... My perception was they were hung up trying to understand the results.”

Peter Whoriskey is a staff writer for The Washington Post handling projects in business, healthcare and health. You can email him at peter.whoriskey@washpost.com

Twilight of the Climate Change Movement

Twilight of the Climate Change Movement
Mario Loyola
 

Don’t be fooled by the post-Paris fanfare: The climate change movement faces big trouble ahead.

The UN’s climate summit in Paris at the end of 2015 concluded with a bang. The world’s governments promised sweeping cuts in carbon emissions. Rich countries promised to help poor ones with $100 billion per year in climate assistance. President Obama quickly declared the agreement “the best chance we have to save the one planet we’ve got.” The consensus quickly jelled that this was a major, historic achievement.

Then came the fizzle: The agreement is non-binding. Secretary of State John Kerry asserted on NBC’s Meet the Press that compliance would be enforced through the “powerful weapon” of public shaming, apparently implying a policy of verbal confrontation toward states that fall short. The Danish scientist Bjørn Lomborg, a prominent critic of the top-down international conference approach to climate change, called the Paris agreement the “costliest in history” if implemented. According to Lomborg, the agreement would “reduce temperatures by 2100 by just 0.05 degrees Celsius (0.09 degrees Fahrenheit)…. This is simply cynical political theater, meant to convince us that our leaders are taking serious action…a phenomenally expensive but almost empty gesture.” NASA scientist Jim Hansen, one of the earliest proponents of the idea that global warming is man-made, slammed the deal as “half-assed and half-baked,” a “fake,” and a “fraud.”Hansen’s assessment is probably close to the mark—and he and his fellow alarmists have only themselves to blame. 

While those who flatly deny the possibility of any global warming can be readily brushed aside, the alarmists have been much too quick to dismiss legitimate questions about precisely what the evidence shows. Indeed, they have frequently treated such questions as heresies to be persecuted, adopting an even more virulently anti-scientific mindset than the one they accuse others of.Meanwhile, on the policy side, the alarmists’ call for worldwide economic controls, including caps on fossil fuels, are largely recycled from previous scientific doomsday fads, such as the oil scarcity scare of the late 1970s. 

Despite the enormous costs these policies would impose, especially on poor countries, they would do virtually nothing to stop anthropogenic climate change, let alone protect anyone from relentless natural climate change that is one of our planet’s most prominent and inescapable features. They are also distracting attention both from investments that would make society less vulnerable to climate change, and from a more pressing crisis, namely the extinction of a large fraction of the world’s plant and animal species due to widespread modification of natural habitat.Don’t be fooled by the fanfare in Paris: The climate change movement faces big trouble ahead. Its principal propositions contain two major fallacies that can only become more glaring with time. 

First, in stark contrast to popular belief and to the public statements of government officials and many scientists, the science on which the dire predictions of man-made climate change is based is nowhere near the level of understanding or certainty that popular discourse commonly ascribes to it. Second, and relatedly, the movement’s embrace of an absolute form of the precautionary principle distorts rational cost-benefit analysis, or throws it out the window altogether. 

As the costs of decarbonization start to hit home, and the public demands greater certainty about the benefits to be gained, the public—and particularly those industries that are hardest hit—will invest in scientific research, in the hopes of achieving a more granular cost-benefit analysis. Something similar is happening to proposed listings under the Endangered Species Act—where major economic interests are threatened, they have responded with enormous investments in scientific research in order to show either that the species in question is not in danger, or that it can be protected by measures far short of the often draconian prohibitions imposed pursuant to the Act. 

These factors will almost certainly produce a more nuanced and less messianic view of the climate problem, with solutions aimed to maximize “bang for the buck” at the margins, where climate threats are most grave, rather than reordering human society in order to “save” a planet that, in the grand scheme of things, is quite indifferent to the state of the climate at any given time.

All sides of the climate change debate have a huge incentive to generate more and better climate science: the alarmists and their more skeptical colleagues all want to prove their points. As our scientific understanding improves, many of the propositions we hear today will have to be modified, and many will be refuted, as has always happened in the history of science. The scientific community may at times be powerfully resistant to revision of its received wisdoms; it took an entire generation for medical professionals to accept the germ theory of disease, despite the fact that the evidence in its favor generated by Pasteur and Koch was clear from the start. But better science wins out in the end.

The greater clarity that better science will bring will open up new opportunities to solve environmental problems both known and unknown, and not a moment too soon. The human race faces challenges that cannot effectively be met at a local or even a national level. These challenges will not be met by a wholesale reordering of human society from the top down, as many of the more authoritarian-minded environmentalists wish. Any attempt to impose command-economy solutions on a global scale will fall far short or outright fail, as the Paris agreement and its precursors show. The right strategy for confronting environmental challenges will have to be based on rational market incentives, rational cost-benefit analysis, and a broad-based consensus about the vital importance of efficient markets. Strategies that distort rational cost-benefit analysis (or the science on which it is based) to suit an anti-market agenda will not work and can only maintain the illusion of legitimacy for so long before they are discredited.

A Brief History of the Pleistocene Ice Age
It’s an amusing irony that fears of global warming have arisen during what is technically an ice age, namely the Pleistocene Ice Age, which began about 2.6 million years ago. A geological “ice age” typically lasts millions of years and is characterized by cycles of glaciation, during which glaciers grow and oceans recede, punctuated by warmer interglacial periods, in which glaciers recede and oceans rise—such as the current Holocene interglacial, in which human civilization has flourished.During glacial periods, the northern hemisphere becomes substantially covered in glaciers, typically several kilometers thick. An abundance of data (from isotopes in ice sheets and the ocean floor, to the fossil record) enables us to reconstruct much of its history. During glaciations, average temperatures typically drop about 20 degrees Celsius below today’s, and sea levels drop about 400 feet below where they are now. During the coldest points in those glacial periods, an adventurous animal can walk from England across Europe and Asia to North America without getting its feet wet. This almost certainly explains the Asian origins of native American populations, which are thought to have crossed the current Bering Strait on foot in repeated waves between 80,000 and 12,000 years ago.

The last glacial period ended starting about 18,000 years ago, the height of the Wisconsonian glaciation, when the first of several dramatic warming trends began. Average temperatures rose and fell and rose again by 20 degrees Celsius in barely 5,000 years, less than the time between Sumerian civilization and the present day. Sea levels, which lag temperature swings by long periods of time, rose 300 feet between 15,000 and 8,000 years ago. That’s an average of more than one meter per century. Among humans, sedentary agriculture first arose when temperatures stabilized near current levels about 12,000 years ago. There was at least one settled community that reached a population of 8,000 inhabitants in Turkey some 9,500 years ago. At the dawn of civilization, man would have experienced floods on a biblical scale.

In fact, major environmental changes have happened in time scales that are readily understandable in terms of human history. The Baltic Sea, for example is typically a freshwater glacial-runoff lake that disappears completely during glacial periods. When the North Sea finally rose high enough to breach the land bridge between Denmark and Sweden there were already large settled communities practicing agriculture. The saltwater ecology along the western edge of the Baltic Sea is not much older than the first pyramids.Before the interglacial period began 18,000 years ago, most of North America was buried under a vast sheet of ice. That glacial period (“ice age” in common parlance) lasted more than 100,000 years, though with significant variations in temperature, glacier cover, and sea levels—mini-cycles referred to as “stadials” and “interstadials.” During that time, anatomically modern humans spread throughout the world across land bridges that connected most of the continents. Our ancestors dominated the warmer climes and competed with Neanderthals for food across the tundra and ice of Europe.The warm interglacial period before that glacial period only lasted from 145,000 to 127,000 years ago. At their maximum, temperatures were significantly warmer than today, with ocean levels about thirty feet higher. Evidence in the form of algae fossils suggests that during at least some part of this period, the Arctic Ocean was completely free of ice cover, during the summer months if not year round. Only Antarctica retained its vast ice sheets and glaciers.

This repeating cycle of 100,000-year glaciations and 10,000 to 20,000 year interglacials has been fairly consistent over the past 2.6 million years. The planet has trundled through the entire cycle dozens of times. If the pattern holds, we are due for another major glaciation sometime in the next several thousand years: The northern hemisphere will again become substantially covered in glaciers, ocean levels will fall hundreds of feet, and the earth’s overall production of plant biomass will fall substantially below what the current human population needs to feed itself. That will pose some ticklish technological challenges even for our hyper-adaptable species. Hopefully, such changes will be incremental enough to allow for adaptation.

It’s impossible to say when (or even whether) this next “ice age” will come, partly because the scientific theories of what drives these epochal glacial cycles are all underdetermined - that is, theories explain part of the climate variation but not all of it. For example, the start of interglacial periods seems correlated to variations in the earth’s orbit. But the extent of orbital “eccentricity” does not fully explain the amount of warming that occurs, implying that other factors and feedback amplifiers are also involved.

It is true, and at least somewhat alarming, that the current atmospheric carbon dioxide level of 400 parts per million (ppm) is far higher than at any time in the past 800,000 years, almost entirely as a result of humans burning fossil fuels. What we hear less often, however, is that during the first 1.8 million years of the Pleistocene Ice Age, carbon dioxide levels were significantly higher than that. Major glaciation occurred a dozen or more times, without taking much notice at all of what should have been a much stronger greenhouse effect. And for 245 million years before that, carbon dioxide levels were vastly higher. So carbon dioxide levels are the highest they’ve been in 800,000 years, but they’re also among the lowest they’ve been in 245 million years. Compared with that 245 million-year record, pre-industrial carbon dioxide concentrations of 280 ppm were perhaps perilously close to the level, around 150 ppm, below which plants cannot grow. It’s always possible to have too much of a good thing, but it bears recalling that carbon dioxide has vital benefits. Plant photosynthesis, which sustains virtually all life on earth, requires an abundance of sunlight, water, and carbon dioxide. 

Heretical Questions

In political discourse, it is often necessary to simplify complex policy matters in order to make them accessible for public debate. But too much simplification can have the effect of stifling public discourse, as in this unfortunate State of the Union statement by President Obama: “The debate is over. Climate change is real.” Of course climate change is real. The climate is always changing. Only the most foolish of the President’s critics believe otherwise, and it doesn’t help his cause to demonstrate that he can be just as foolish.

The evidence is overwhelming that the planet has been warming off and on for several centuries. There is also compelling evidence that at least some significant part of this warming is attributable to carbon dioxide from the burning of fossil fuels since the mid-20^th century. There is good scientific reason to believe that increasing concentrations of greenhouse gases almost certainly constitute a net contribution to global warming. But crucial questions remain about the relative importance of natural factors that influence climate. One of these is the sequestration of carbon dioxide by biomass on land and in the oceans. Another concerns cloud cover, which reflects a large amount of solar radiation back into space, and which earlier models of climate change did not take into account (because it’s very hard to get right). The simple climate models of ten or twenty years ago are now showing their age amid a flood of new data, and the far more complex, uncertain, and varied picture those data illustrate. The President is therefore wrong in the sense that, for the most crucial scientific questions, the debate is just beginning.

The questions begin with the fact that while there is some correlation between temperature trends over the recent past and “anthropogenic” (or human-caused) carbon dioxide, the correlation is not very strong. The shape of the warming curve does not track the shape of the curve for increased carbon dioxide concentrations. For example, About 40 percent of the warming since 1900 happened in the first half of the 20^th century, when “anthropogenic” carbon dioxide was insignificant. That warming could not have been caused by human behavior. Then, from 1945 to 1975, just as major amounts of carbon dioxide from burning fossil fuels start to appear in the atmosphere, there was a major “hiatus” during which global average surface temperatures held steady or actually dropped slightly—again, no correlation. From 1975 to 2000 there appears to have been very rapid warming. But then, as anthropogenic carbon dioxide levels continued to increase, another hiatus in temperatures appears to have set in with the strong El Niño year in 1998. While there are major discrepancies among different data sets, and new data are still being collected, the IPCC’s latest report concedes that the rate of warming since 2000 has been substantially less than predicted by climate models in response to rising levels of carbon dioxide.

The public debate is dominated by simplistic claims that “climate change is man-made,” which might lead one to think that all of the current warming trend is man-made. But nearly all climate scientists accept that many factors influence temperatures, including major shifts in patterns of ocean circulation (such as the very strong El Niño, largely responsible for the warm Christmas Day 2015 temperatures in North America), variations in the earth’s orbit, variations in solar activity, and volcanic activity. The “attribution statement” in the IPCC’s latest assessment report is carefully couched: “It is extremely likely that more than half of the observed increase in global average surface temperature from 1951 to 2010 was caused by the anthropogenic increase in GHG [greenhouse gases] and other anthropogenic forces together.”

The distinction between “more than half” (the IPCC summary’s of scientific literature) and “all” or “nearly all” is crucial from the point of view of public policy. If only about half the observed warming is due to human activity, the cost-benefit analysis of currently proposed policies becomes far more dubious, and reveals another problem: As much as half the current warming trend (whatever that is) could be due to natural causes, and current policies will do nothing to address that.

To see why, it’s crucial to focus on this precise scientific question: How much do temperatures actually increase when atmospheric carbon dioxide increases? Scientists express this relationship as a measure of “equilibrium climate sensitivity,” defined as how many degrees average global temperature will increase as a result of doubling atmospheric carbon dioxide. Virtually all the climate models used in the IPCC’s worst-case predictions of dangerous global warming presume a worst-case scenario equilibrium climate sensitivity (ECS) of 3.0 to 3.5 degrees Celsius. But leading IPCC scientists have concluded that if humans were responsible for all observed warming since 1971, the ECS would be around 2.0 degrees Celsius. And if humans are only responsible for about half of the observed warming, as the IPCC itself admits is quite possible, that implies an ECS closer to 1.0 degrees Celsius.

A reliable figure for ECS continues to elude our grasp, but with an ECS of 1.0 degrees Celsius, the case for sweeping reductions in carbon emissions is greatly weakened. At that level of climate sensitivity, even if carbon dioxide emissions continue to increase unabated, temperatures would increase significantly less than the stated goal of the IPCC’s, which is warming of no more than two degrees Celsius by 2100. (This may explain why the Paris agreement moved the goalposts to a new goal of less than 1.5 degrees Celsius by 2100). But in that case, IPCC’s worst-case scenario would then be non-catastrophic by the IPCC’s own definition.

The policy implications are dramatic. Under this scenario, which lies well within the IPCC’s forecast, even dramatic reductions in carbon dioxide emissions would have no measurable impact on temperatures. And the natural factors responsible for as much as half the recently observed warming would presumably continue warming the planet, oblivious to any reduction in carbon emissions.The key point is this: The IPCC’s latest “attribution statement” (extreme confidence that more than half the observed warming is due to humans) would be correct even if ECS is only 1.0 degrees Celsius and expected increases in carbon dioxide pose essentially no risk of catastrophic climate change.

Far from honing in on a reliable value for the crucial ECS metric, more recent data have only increased the uncertainty surrounding it. As climate scientist Judith Curry of the Georgia Institute of Technology points out, while the IPCC’s AR4 report (2007) expressed an ECS “best estimate” of 3.0 degrees Celsius, the AR5 report (2013) doesn’t express a “best estimate” ECS at all. “The stated reason for not citing a best estimate in the AR5,” notes Curry, “is the substantial discrepancy between observation-based estimates of ECS (lower), versus estimates from climate models (higher).”

This highlights an important self-correcting feature in the development of climate science. Yes, it’s true that many major journals reject articles that critique the current consensus, and that funding priorities strongly reinforce the consensus. But even the strong bias in favor of more dire findings, which has been introduced into scientific inquiry by the pervasive politicization of the issue, cannot readily invent false data. Every year produces more raw data than the year before, and the discrepancies between the new data and the simple climate models are increasing. Alarmists say that discrepancies are to be expected, and models are meant to be refined. But they have boxed themselves in with misleading claims to certain knowledge where in fact considerable uncertainty remains. Uncertainty about risks is not necessarily fatal to a policy of precaution, and but false claims to certainty usually are, sooner or later. Witness the Iraq War and Saddam’s non-existent WMD.A close look at more specific questions reveals even deeper uncertainties. Antarctic sea ice has increased steadily since the 1970s. The planet appears to have been warming, generally though inconsistently, since the “Little Ice Age” of the late 18th century and early 19^th century, when George Washington repeatedly recorded snowfall at Mount Vernon in early November. And even the Little Ice Age appears to have been just a hiatus in a broader warming trend that has lasted about 400 years. The early climate models of a few decades ago predicted that we had already, or would soon, exceed the maximum temperatures of both the Holocene Maximum 5,000 years ago and the Medieval Warming Period a thousand years ago, when Vikings wrote of grapes growing in Vinland (coastal North America and Newfoundland)—the two hottest periods of the current interglacial. Those predictions have not been borne out by more recent data: Average temperatures are still far short of both of those (relatively recent) peaks.

The flood of new data has forced the United Nations to revise downward its prognostications of ocean-level increases. The worst-case sea level rise by 2100 was revised downward from 3.7 meters in the first IPCC report to 1.2 to in the second, to 0.8 in the third, and to 0.6 in the fourth. The most recent IPCC assessment report, AR5, expressed “medium confidence” that there is a least a 66 percent probability of sea levels rising from 0.45 meters to 0.82 meters in a high-carbon-emissions scenario.

The prognostications of extreme weather, which alarmists matter-of-factly blame on anthropogenic climate change, have been increasingly discredited. Neither tornadoes nor hurricanes have been more frequent or intense since 1950 than they were in the half-century before—though we can’t know for sure because precise data on tornados and cyclones is too recent. Likewise, predictions of infectious diseases such as malaria spreading more widely have also been largely discounted in more recent IPCC reports, because vulnerability to infectious diseases correlates less with warm climates than with poverty and the poor public health conditions it entails, both of which risk being greatly exacerbated by strong decarbonization policies.

This recurring failure to explain the past and predict the present hasn’t stopped alarmists from claiming, as the President did recently on Twitter, “Ninety-seven percent of scientists agree: climate change is real, man-made and dangerous.” The President perhaps was relying on the most famous of the surveys claiming a near-universal consensus on man-made climate change—a 2013 survey by the Australian John Cook and several colleagues in the journal Environmental Research Letters. Cook and his colleagues surveyed the abstracts of 11,944 peer-reviewed journal articles drawn from a simple database search of key terms. They classified the papers on the basis of whether the papers expressed an opinion on whether “humans are causing global warming” and, if so, whether the opinion embraced or rejected the consensus. They found that about two-thirds expressed no opinion, and of the third that did, nearly all embraced the consensus.

Ninety-seven percent of scientists agree: #climate change is real, man-made and dangerous. Read more: http://t.co/4lEEBYtVqf

— Barack Obama (@BarackObama) May 16, 2013

The generality of Cook’s criterion elides the same crucial distinction as the IPCC’s most recent statements attributing global warming to anthropogenic carbon dioxide: There is a huge difference between admitting that anthropogenic carbon dioxide is a driver of current global warming, and claiming that it responsible for virtually all current global warming. On the crucial question of how much of the observed warming is attributable to humans, only a tiny fraction of the studies offered “explicit endorsement with quantification”; the rest offered either “explicit endorsement without quantification” or “implicit endorsement.” The single most telling weakness of the Cook study is that very few scientists are prepared to offer even a rough estimate of how much of current global warming is attributable to anthropogenic carbon dioxide. Many climate scientists who agree that humans contribute to global warming are skeptical of prognostications of catastrophic climate change. The Cook survey throws all of these into its 97 percent consensus, a remarkable achievement in packaging a survey that quite clearly shows considerable diversity and uncertainty in what peer-reviewed scientific papers have actually found.

Meanwhile, Michael Mann’s famous “hockey stick” study has been savaged by the scientific community. That study purported to show temperatures spiking to dramatic new heights as a result of anthropogenic carbon dioxide; it was, some will recall, the most influential factoid of Al Gore’s An Inconvenient Truth. Scientists have criticized Mann’s misuse of proxy data, his failure to fairly reflect the complexity of the climate system, and above all his statistical methodology, which produced a hockey stick 99 percent of the time in 10,000 sets of randomly generated data. The Annals of Applied Statistics has devoted an entire issue to the methodological problems of the Mann study.

This blurring of the lines between inquiry and advocacy confuses the public and leaves scientists open to charges of professional dishonesty. The fact that the apocalyptic vision of impending doom is a matter of obligatory orthodoxy gives the movement a quasi-religious tone, and lends itself to the persecution of “skeptics” as heretics. Of course, such an attitude ignores the essence of the scientific spirit, which is one of constructive skepticism. It also lends itself to policy proposals of a revolutionary—or reformationist, to extend the religious metaphor—brand that ignores or discounts rational cost-benefit analysis.Revolutionary PoliticsThe climate change movement is a diverse coalition. There are captains of capitalism (George Soros, Michael Bloomberg, Tom Steyer) and there are inveterate enemies of capitalism (Naomi Klein). There are Greens opposed to free trade, and those (like Ignacio Ramonet, publisher of Le Monde Diplomatique) who think that the root of all evil is the World Bank, IMF, and globalization. There are Marxists who believe in state suppression of the free market. And there are eco-socialists, red-green activists who take a dim view of the “materialism” of economic development but nevertheless believe in a mixture of Marxism and environmentalism.

In the United States, where unadulterated socialism usually doesn’t sell well, the climate alarmists put a decidedly capitalist face on their policy prescriptions. Led by prominent social-democratic billionaires, these capitalist-climate-alarmists go for huge clean energy subsidies and come armed with all kinds of theories about how a 50 percent or even 80 percent renewable energy mandate would pay for itself. (It will only do so if there are technological breakthroughs in renewable energy technology, and those breakthroughs are far more likely to occur through systematic investment in research and development, not in huge but diffuse subsidies to various private companies whose R&D capacities are at best uneven.) This political marketing strategy has infused the regulatory process itself in the Obama Administration. The Environmental Protection Agency claims that its Clean Power Plan will create add to GDP. Perhaps, but there is no question that the subsidies translate into a form of patronage support for Democrats. The Clean Power Plan essentially forces “red” states like Texas (and chiefly Texas, in terms of overall carbon emissions reductions) to adopt the electricity mix of “blue” states like California—precisely because electricity is so much cheaper and more reliable in Texas than in California, conferring a huge advantage in interstate competition.

Outside the United States environmentalists tend to be more socialistic (witness the prevalence of Green parties in Europe). Their policy proposals usually involve some combination of “a revolution in the way people think and live, to worldwide economic controls on, for example, population growth, energy production, or carbon emissions—the last of which implies indirect if not direct control over virtually all economic activity. Americans across the political spectrum might agree that the scientific evidence on climate change justifies certain precautionary measures, and that naturalism is an important value. But with so many alarmists, from Bill McKibben to Naomi Klein, calling for an end to capitalism as we know it, the debate tends to go off the rails from the start. Hence, for example, John Holdren, Obama’s senior advisor for science and technology, in his 1973 book Human Ecology, called for “a massive campaign” to “de-develop” the United States, including redistribution of wealth both within and among nations.

The socialist bent of the alarmists’ policy prescriptions is especially suspicious because we’ve heard it all before—from the Club of Rome’s Limits to Growth to professor Paul Ehrlich’s The Population Bomb. Those doomsday scenarios were soon followed by the fear of a catastrophic oil shortage, popular later in the 1970s. There were no catastrophic food or energy shortages, of course, and the “peak oil” scare petered out even faster than the population bomb scare. There’s no way to predict the next “scientific” doomsday fad, but we can be fairly certain that it will include frantic calls for government or “global” government controls on industrial activity. Like proponents of bygone doomsday fads, most of today’s climate alarmists share an unshakable conviction that humans are the problem and that nature in its “natural” state is pristine and perfect. That is the 19^th century Romantic spirit at the heart of today’s environmentalist movement, the hallmarks of which are a deification of nature and a revulsion for the works of human beings, not to exclude innovations that lead to dramatic improvements in material well-being.But that begs an important question: Do climate alarmists want to eliminate the human impact on climate, regardless what the climate would be doing otherwise? Or are they trying to eliminate climate change itself, regardless of cause? Obama’s loose talk about “saving the planet” seems to elide rather than to clarify whether it’s really the planet that needs saving from mankind, mankind that needs saving from itself.

The question hasn’t gone unnoticed. In Slate, Joseph Romm concedes that the planet will be fine no matter what we do, so we should be more worried about ourselves. We live on a planet where adaptation is a necessary skill. Yale economist William Nordhaus notes that the era of human expansion has coincided with a 12,000-year period of uncharacteristically stable climate. He surmises that human civilization may be unusually dependent on this stability. Hence, pace Nordhaus, if that stability is now ending, our goal should be to modify the climate through climate engineering, to render it stable enough for human habitation. MIT physicist David Keith agrees, proposing a low-cost solution: inject sulfuric acid into the stratosphere, where the right amount would reflect enough sunlight back into outer space to neutralize a dangerous warming trend.Imagine something that is entirely possible - that a single such technological breakthrough enables us to control the world’s average temperatures. Could we then agree on what the ideal temperature should be? Is the current global average temperature the ideal one? Many would take that for granted, and climate alarmists appear to presuppose it, but the proposition is hardly self-evident. That is especially true given that even in the worst-case scenario, higher temperatures would not be completely devoid of benefits. Far more people die of cold than of heat. Marginally higher temperatures and carbon dioxide levels would likely increase the world’s overall production of plant biomass, and lengthen growing seasons, thereby reducing the proportion of the world’s land required for agricultural production and increasing the amount of land available for high-quality natural habitat.

To read the IPCC reports, alarmists find the idea of adapting to climate change far less satisfying than the idea of preventing it. But their focus on worldwide economic controls boils down to a kind of climate engineering, because it presupposes that humanity should not learn to live with a changing planet. Hence we are to believe that the most adaptable species that has ever existed, a species so sophisticated that it can survive in outer space, requires an absolutely stable average temperature and sea-level in order to survive. This defies common sense.

Human civilization faces many challenges. We face an ever-present risk of dangerous climate change due to natural causes. We face an immediate crisis in the rapid loss of the world’s most valuable and critical habitat, due chiefly to farming and logging. The future will bring further challenges for which we will find ourselves far less prepared than we could have been. But frightfully little attention is being paid to these risks, for the simple reason that they don’t fit snugly into the environmentalists’ essentially anti-industrial agenda.

Man-made climate change, on the other hand, is the perfect vehicle for advancing that agenda. Dealing with it requires choking off fossil fuels, a top-down reorganization of economic activity, and income redistribution. If alarmists were really interested in protecting humans against climate change, they would be helping Bangladesh adapt to monsoon floods and thereby avoid thousands of deaths every few years, instead of insisting on green energy boondoggles that will never save a soul there or anywhere else.

The Paris conference achieved agreement on an annual $100-billion Global Climate Fund to help developing countries reduce their carbon footprint. The money would be far better spent on adaptation assistance, to make sure that poor societies preserve critical habitat while reinforcing their access to things they will need in the event of really catastrophic climate change: food, water, and fossil fuels.In the meantime, every year will bring more new scientific research to bear on the climate debate. Whatever the current “consensus,” new research is certain to challenge it. The primitive urge to “call out” the skeptics can silence and punish individual scientists. But it cannot alter the structure of scientific revolutions in a scientific age. 

Mario Loyola is a senior fellow at the Wisconsin Institute for Law and Liberty.