01.29.07
Climate Change Revisited
From the WWNK:
By Doug Hornig
In March 2004, we ran an article on a Pentagon-commissioned study on the possibility of abrupt and drastic climate change, such as happened 12,000 years ago when, according to estimates, the average global temperature rose by seven degrees in only twenty years and put a decisive end to the most recent ice age.The result of the study, a brief paper titled, An Abrupt Climate Change Scenario and Its Implications for United States National Security, pushed certain computer models to their extreme, at which a sudden rise in global temperature results in a shutting down of the Gulf Stream and, counter intuitively, colder conditions for much of the planet.
That, of course, is just one projection among many. Other researchers have modeled quite different futures, with conditions both more and less dire.
In the past two and a half years, the debate over global warming, its potential effects, and (especially) the human role in bringing it about, has only intensified—with Al Gore’s widely seen movie, An Inconvenient Truth, and his packed public lectures leading the way. Thus this seemed like an opportune time for us to revisit the topic.
The central question, it would seem, has been answered. Are we in a period of global warming?
Yes, sort of.
As always, the devil is in the details. While much has been made of record-breaking thermometer readings and “unprecedented” heat waves, the average global temperature has risen by just 1°F in the past hundred years. If this doesn’t seem like much, well, it isn’t and, moreover, it has been unevenly distributed: temperatures rose from 1920-1940, decreased for the next thirty years, increased again until the mid-1990s, and have been nearly flat since 1998.
This is not the result one would expect if human-generated greenhouse gas emissions, which have constantly increased, inevitably caused temperatures to rise. But such fluctuations—and even more dramatic ones—are not only commonplace, they are inevitable, given a dynamic feedback system like that which exists between the Earth and Sun. There is even one current theory that posits super-cycles, within which the average global temperature varies between 120°F and minus 50. It’s a wonder that life has endured at all.
How then should we address the coming 21st-century climate change (something will surely happen), and the proposition that it will primarily be driven by man who, many claim, is creating a massive greenhouse effect through the burning of fossil fuels?
There are many aspects to this but, to begin at the beginning, Al Gore and others, including most of the media, have been telling us there now exists a “consensus” viewpoint on man-made (anthropogenic) global warming (or AGW). For purposes of economy, let’s call them the alarmist faction. Furthermore, we’re told that the faction questioning the majority view—we’ll call them the skeptics—consists of only a tiny handful of shills for the oil industry.
Not so.
Take the famous “hockey stick,” for example. This is a graph that is routinely trotted out by the alarmists, and plays a large role in Gore’s film. It purports to show that global temperature was flat for most of the past millennium, before suddenly and ferociously spiking upward during the 20th century, thereby creating the business end of the hockey stick. I.e., AGW is out of control.
The graph was created by Dr. Michael Mann, then a climatologist at the University of Massachusetts, in a 1999 paper, and it was immediately and rather uncritically accepted.
One problem with Mann’s and others’ attempts to pin down global temps is that the thermometer wasn’t invented until the early 18th century. For data before that point, we have to rely on reconstructions based on inferences from historical records, and climate proxy indicators, such as tree rings (upon which Mann heavily relied), corals, lake sediments and ice core samples. And even there, most of the work has been done in, and on, the Northern Hemisphere, since that’s where most of the people are; we know little about what may have been going on to our south.
(Recent satellite tropospheric temperature data from NASA indicate that the Southern Hemisphere hasn’t heated up at all in the past 25 years; perhaps we should be discussing “north hemispheric” rather than “global” warming.)
Now, granted that research scientists’ methodologies have become increasingly sophisticated over the years, and high-speed computers have enabled the concatenation of huge amounts of data from many different sources. Many climatologists feel confident of their inferences about a given historical period. Nevertheless, it’s wise to keep in mind that there are disagreements, that all estimates are subject to considerable margins of error, and that anyone who purports to “know” for certain exactly how hot or cold it was in 1066 is being disingenuous, at best.
So what are we to make of Mann’s graph, in which actual thermometer-recorded temperatures for the past 150 years are casually grafted onto many more centuries of tree ring records? That’s a bit like gluing an apple to an orange and calling it a new type of fruit. It’s sloppy science.
Even if we completely accept the inferred temperatures scientists have given us—and even if we ignore the large margin of error Mann built into his original graph and which his disciples never bother to reproduce—there still emerges a very major problem with the hockey stick: the graph shouldn’t be flat between 1000 and 1900. During those nine hundred years there were some very substantial fluctuations. Most notable are the Medieval Warm Period that began abruptly around 1000 and peaked somewhat above today’s conditions around 1250 (thereby allowing the Vikings to establish farms in Greenland); and the Little Ice Age of the 15th-18th centuries, when it averaged a degree and a half colder.
The hockey stick simply ignores these periods, making them instead roughly flat, an alteration that geophysicist David Deming, of the University of Oklahoma, calls deliberate. He cites a colleague who, hoping to stir up alarmist sentiment over global warming, once wrote him that, “We have to get rid of the Medieval Warming Period.”
They did. If you leave it in, along with the Little Ice Age, then the graph no longer looks like a hockey stick, but more like a snake slithering along the ground. We are at one of the peaks of warmth, but there was another a thousand years ago, along with a really frigid trough four centuries back. With this perspective, as Dr. Deming writes, “late-twentieth-century temperatures are not anomalous or unusually warm.”
Dr. Deming’s opinion was borne out by a June 2006 publication from the National Academy of Sciences, titled Surface Temperature Reconstructions for the Last 2000 Years. In it, the NAS slammed Mann’s ignoring of the major hot and cold periods. Additionally, it said that “substantial uncertainties” surround the notion that the last half of the twentieth century was the warmest of the millennium and that, while the uncertainty increases the farther back in time one goes, “not all individual proxy records indicate that the recent warmth is unprecedented […] Even less confidence can be placed in the original conclusions by Mann et al. (1999) that the 1990’s are likely the warmest decade, and 1998 the warmest year, in at least a millennium …”
Commenting on the NAS study, the U.S. Senate’s leading skeptic, James Inhofe (R-OK), said in a September 2006 floor speech, “This report shows that the planet warmed for about 200 years prior to the industrial age, when we were coming out of the depths of the Little Ice Age […] Trying to prove man-made global warming by comparing the well-known fact that today’s temperatures are warmer than during the Little Ice Age is akin to comparing summer to winter to show a catastrophic temperature trend.”
Furthermore, the line at the end of the graph has suddenly gone flat. “There is a problem with global warming,” says paleoclimatologist Bob Carter of Australia’s James Cook University, “it stopped in 1998.” Despite all the excess CO2 our SUVs have been pumping into the atmosphere, Carter says, “official temperature records of the Climate Research Unit at the University of East Anglia in the UK [show that] the global average temperature did not increase between 1998-2005.”
All in all, that is one broken hockey stick.
But isn’t there still a “consensus” about global warming? Didn’t most of the world’s nations agree on that at Kyoto?
Well, consider a letter written to Canadian Prime Minister Stephen Harper in April of 2006, in an effort to get the government there to review actual climate change evidence before implementing provisions of the Kyoto Protocol.
The letter leads off by saying: “As accredited experts in climate and related scientific disciplines, we are writing to propose that balanced, comprehensive public-consultation sessions be held so as to examine the scientific foundation of the federal government’s climate-change plans […]
“Observational evidence,” it continues, “does not support today’s computer climate models […] While the confident pronouncements of scientifically unqualified environmental groups may provide for sensational headlines, they are no basis for mature policy. The study of global climate change is […] an ‘emerging science,’ one that is perhaps the most complex ever tackled. It may be many years yet before we properly understand the Earth’s climate system. Nevertheless, significant advances have been made since the protocol was created, many of which are taking us away from a concern about increasing greenhouse gases. If, back in the mid-1990s, we knew what we know today about climate, Kyoto would almost certainly not exist, because we would have concluded that it was not necessary […]
“When the public comes to understand that there is no ‘consensus’ among climate scientists about the relative importance of the various causes of global climate change, the government will be in a far better position to develop plans that reflect reality…”
After all, the authors say in conclusion, “It was only 30 years ago that many of today’s global-warming alarmists were telling us that the world was in the midst of a global-cooling catastrophe. But the science continued to evolve, and still does, even though so many choose to ignore it when it does not fit with predetermined political agendas.”
Who signed this letter? 61 of the world’s most prominent experts in the fields of Earth science, climatology, meteorology, geophysics, math and economics. Without them, the “consensus” is thin indeed.
Another consensus-buster came in the form of a reexamination of a study by UCSD social scientist Naomi Oreskes, published in Science, claiming that a review of abstracts of scientific papers on climate showed a 100% agreement that global warming is not the result of natural variations. Oreskes’ study was featured in An Inconvenient Truth.
Unfortunately for Oreskes and Gore, Dr. Benny Peiser, a British social scientist, took a close look at the study and found that Oreskes had referenced only 928 out of nearly 12,000 available papers on the subject. Even among those 928, Peiser found that only 2% wholly endorsed the view that human activity is driving global warming, and several of the studies actually opposed that conclusion.
Another striking image that many will remember from An Inconvenient Truth is of huge chunks of glacial ice breaking off from Antarctica and floating away, presented as “evidence” that the polar continent is warming.
Actually, no. This is what glaciers do when they’re growing. “The breaking glacial wall is a normally occurring phenomenon which is due to the normal advance of a glacier,” says Dr. Boris Winterhalter, a professor of marine geology at the University of Helsinki. “In Antarctica, the temperature is low enough to prohibit melting of the ice front, so if the ice is grounded, it has to break off in beautiful ice cascades.”
Some sections of Antarctica are warming, true enough. But others are cooling, with variations “probably because of a small change in the position of the low pressure systems,” says Dr. Wibjörn Karlén, a professor emeritus of geology at Stockholm University. Overall, Karlén says, the “mass balance” of Antarctica is positive—more ice is building up than melting off.
That’s what’s happening at the bottom of the world. What about at the top? Well, the Arctic was warmer in the 1930s than it is now. It cooled significantly in the ’60s. It warmed until the early ’80s, then cooled again through the mid-’90s. After a sudden 30% drop in ice thickness in the Canadian Arctic between 1996-1998, it has been rebuilding and is now near “normal” levels, whatever that means.
A 2003 paper by Igor Polyakov of the University of Alaska found no overall Arctic temperature rise since 1940. In fact, “For several published records, it is a decrease for the last 50 years,” Karlén says.
Similarly, scare stories about the melting of Greenland’s glaciers and the resulting rise of sea levels are premature. In October 2005, a study of Greenland ice was published by researchers from Bergen University’s Nansen Environmental and Remote Sensing Center (NERSC). The researchers analyzed “a continuous satellite-altimeter height record of Greenland Ice Sheet […] elevation changes over an 11-year period, 1992-2003.”
The NERSC team found that “below 1500 meters, the elevation-change rate is minus 2.0 ± 0.9 cm/year, in qualitative agreement with reported thinning in the ice-sheet margins” (i.e., the alarmists are correct that glaciers are melting along the coast). However, “an increase of 6.4 ± 0.2 cm/year is found in the vast interior areas above 1500 meters.” Averaged over the bulk of the ice sheet, the net result is a mean increase of about 5.4 cm/year. In plain terms, the Greenland ice is expanding, not contracting.
Alpine glaciers? Says Richard Lindzen, professor of atmospheric science at MIT, “Alpine glaciers have been retreating since the early 19th century [i.e. before the Industrial Revolution], and were advancing for several centuries before that. Since about 1970, many of the glaciers have stopped retreating and some are now advancing again. And, frankly, we don’t know why.”
There has also been steadily accumulating, supporting evidence that temperatures today bear about the same relationship to the millennial mean as did those in the Medieval Warm Period, to the upside, and the Little Ice Age, to the downside.
Researchers using proxies other than tree rings have fashioned a climate picture that is remarkably coherent, no matter where on the globe they look. To take one example, in 1996 Lloyd Keigwin, Senior Scientist of Geology and Geophysics at the Woods Hole Oceanographic Institution, published a 3,000-year reconstruction of sea temperatures in the Sargasso Sea, using radiocarbon dating correlated with marine organism populations found in seabed sediments.
Keigwin’s data clearly delineate the Medieval Warm Period (sea temps better than two degrees above the mean) and the Little Ice Age (more than two degrees below it), as well as spikes as high as four degrees above the mean in the first millennium B.C. Today, the Sargasso is right at the mean.
Other proxy studies have involved the study of coral off of Puerto Rico; of Kenyan and Taiwanese lake bed sediments; of oxygen-18 isotopes from ice cores in the Peruvian Andes and from South African stalagmites; and much more. In all of these studies, our era stands near the mid-point of temperature extremes between the Little Ice Age and the Medieval Warm Period.
Yet alarmists continue to proclaim that AGW is out of control.
One of the smoking guns they use is a 1996 report from the UN’s Intergovernmental Panel on Climate Change (IPCC). The IPCC’s website explains that it “does not carry out research nor does it monitor climate related data or other relevant parameters. It bases its assessment mainly on peer reviewed and published scientific/technical literature.” The panel is composed of representatives appointed by governments and organizations. Participation of delegates with appropriate expertise is “encouraged.”
In ’96 these experts concluded that, “The balance of evidence suggests a discernible human influence on global climate,” and set the basis for Kyoto.
However, Dr. Dick Morgan, a climatology researcher at England’s Exeter University, notes that the globe is anything but uniform. Along with the warming parts, he says, there are massive areas that are cooling, including the NW Atlantic, North and South Pacific Ocean, the Amazon valley, north coast of South America and the Caribbean, the eastern Mediterranean, Black Sea, Caucasus and Red Sea, New Zealand, and the Ganges Valley in India.
Furthermore, Morgan questions the IPCC’s methodology. “Had the IPCC used the standard parameter for climate change (the 30-year average) and used an equal area projection, instead of the Mercator (which doubled the area of warming in Alaska, Siberia and the Antarctic Ocean), warming and cooling would have been almost in balance.”
And while we’re on the subject of methodology, one further note. The alarmists’ dire scenarios are based on computer models of the planet’s future, and models are always iffy, to say the least. They depend on what data is put in and how that data is massaged. With regard to weather and climate, they’re often way wrong. Remember the ultra-violent hurricane season computers warned about for the summer of 2006? Didn’t happen. But no doubt, after the savage storms of 2005, big hurricane seasons will continue to be predicted. Any of us can do that, with or without a super-computer and, eventually, the laws of probability will make sages of us.
Are the alarmists right about anything, then? Yes. For example, sea levels are rising. But then, they have been since the peak of the last Ice Age, 18,000 years ago. They’ve risen some 400 feet in the interim. “In recent millennia,” writes S. Fred Singer, an atmospheric physicist and professor emeritus of environmental science at the University of Virginia, “the rate has been 18 cm (7 inches) per century—and there is good argument for this rate to continue until the next ice age. Tidal gauges show no acceleration during the 20th century but only a steady rise […] Evidently, the rise expected from melting glaciers and a warmer, expanding ocean is largely offset by loss of water from increased ocean evaporation and more ice accumulation on the Antarctic continent.”
It is also true that atmospheric carbon dioxide levels are increasing, from about 280 parts per million in the 19th century to some 387 ppm today, and that humans are primarily responsible for this. That’s about a 38% jump in 100+ years, something the alarmists find, well, alarming.
It’s not, Professor Lindzen maintains, writing that, “carbon dioxide is an infrared absorber (i.e. a greenhouse gas—albeit a minor one), and its increase should theoretically contribute to warming. Indeed, if all else were kept equal, the increase in carbon dioxide should have led to somewhat more warming than has been observed, assuming that the small observed increase was in fact due to increasing carbon dioxide rather than a natural fluctuation in the climate system.”
Not to mention that the relationship between CO2 levels and temperature is far from clear. There is an intricate interplay between release of the gas by humans and natural sources, and uptake by the ocean, plants and soil. Given the dynamism of the process, it is a bit surprising that atmospheric carbon dioxide has remained as stable as it has for the past millennium, before spiking up, in hockey stick fashion, only recently.
Will the upward curve continue indefinitely, as alarmists fear? Or will some other element of the system change, bringing CO2 levels down again? No one knows. What is known is that there have been more significant surface temperature changes during the past thousand years than we are experiencing today, and that CO2 levels were not a factor.
What was the deciding factor, then? Again, no one can say, except that it was probably a combination of ingredients.
The most important of these is the amount of solar radiation that is received on the Earth’s surface. Everyone agrees that greenhouse gases like carbon dioxide (and, much more importantly, water vapor) can serve to trap the sun’s heat and raise surface temperatures. But it’s a feedback system, depending not only on greenhouse gas levels, but on how much heat there is to trap, and that varies for a number of reasons.
For one, the sun itself goes through periods of greater and lesser radiation, with the presence or absence of sunspots being a good indicator. Sunspots are cyclical. So is the variation in the shape of the Earth’s orbit; when it’s at its most elliptical, it receives about 20% less radiation than when it’s at its least elliptical, a state it’s now approaching. Also of influence are the regular changes in the tilt of the Earth’s axis and the effects of planetary wobbling on that axis.
Finally, there’s one other question that’s seldom posed: what are the benefits of global warming? Now, we’re not talking about it becoming so hot that the Earth becomes a skillet and we the bacon. But no model foresees that.
Some will be negatively impacted, but that’s true of any change, man-made or natural. On the other hand, warmer temperatures mean later frosts and longer growing seasons. Crops could be raised where they cannot today. Ocean evaporation would rise, increasing the global supply of fresh water. Farmers could repopulate Greenland.
To us, that doesn’t sound bad. What sounds much worse is that we may have the enormous good fortune to inhabit one of the most benign climatic eras ever, and that ice ages will continue to alternate with interglacials like the present. The giant glaciers tend to grow and recede on a 12,000-year cycle, which means they’re about due to return again. When and if they do, they’ll override our land, flatten our proud skyscrapers, and relentlessly drive humanity into ever more densely populated southern latitudes. Those already living there are not likely to open welcoming arms.
It isn’t a pretty picture. Trapping a bit more of the sun’s heat looks like a very viable alternative.
To sum up, in the spirit of full disclosure we cheerfully confess that we are not physicists, or climatologists, or any other kind of authority on the subject of global warming. We don’t have a clue what’s up for 2007, much less the coming century—best guess based on the evidence we’ve reviewed: continued moderate warming, due in some part to human activity—and we rather suspect no one else does, either. All we did was look into the debate, and we hope that we’ve brought to our readers’ attention the fact that there is a debate, that the absolute “consensus” you hear about is a myth.
The consensus tale has been placed in the hands of some very potent myth makers, including prominent scientists, politicians, and most members of the media. We don’t believe that all of them have been deliberately lying to us, although some have.
We do believe that the debate should be taking place out in the open, with both sides presenting evidence, rather than engaging in name calling. We also believe the mass media should do a better job of framing the debate, but we doubt that they will. Fear sells, and the absence of fear is a non-starter. It’s just that simple. The media has glommed onto the alarmists’ point of view, because it is apocalyptic and generates better headlines. The skeptics get short shrift.
Alarmist and skeptic alike, though, agree on one thing: The sun will eventually burn itself out, leaving Earth as a cold, lifeless rock. Now that’s global climate change.