Kyoto en het broeikaseffect #2

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Op woensdag 17 mei 2006 19:23 schreef Sidekick het volgende:

Welke allesomvattende theorie?

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Scare of the Century
The alarms and assertions about global warming have gone reprehensibly too far

JASON LEE STEORTS

But what, oh what, would the earth do without Time magazine?

“Suddenly and unexpectedly,” Time announced in a recent issue, “the crisis is upon us.” Haven’t noticed the crisis? You must not be looking very hard. “The climate is crashing, and global warming [what else?] is to blame.” Time accordingly devoted a special report to saving Mother Gaia. The report is half anti-Republican polemic, half catalogue of global warming’s supposed ills — and none receives greater emphasis than the melting of polar ice. We see a photograph of a polar bear, standing all by his lonesome at the water’s edge, and are told that the poor fellow might drown because “polar ice caps are melting faster than ever.” Later, we learn that “the journal Science published a study suggesting that by the end of the century, the world could be locked in to an eventual rise in sea levels of as much as 20 ft.”

Science magazine has itself been prone to hysteria. The issue that Time mentions contains no fewer than eight studies and articles about the ice caps, and begins with a news story warning that “startling amounts of ice slipping into the sea have taken glaciologists by surprise; now they fear that this century’s greenhouse emissions could be committing the world to a catastrophic sea-level rise.” The policy implications of such reportage are clear, but in case you missed them, Time connects the dots: “Curbing global warming may be an order of magnitude harder than, say, eradicating smallpox or putting a man on the moon. But is it moral not to try?”

The answer is, yes, it may indeed be moral not to try. What is not moral is to distort the truth for political ends — which is precisely what has been done with the ice-caps story. Here’s what you haven’t read.

The world has two major ice sheets, one covering most of Greenland and the other covering most of Antarctica. While melting sea ice has captured its share of attention, it’s the land sheets that matter. Sea ice is already in the water, so its melting doesn’t raise ocean levels. But if land ice melts, the sea gets higher. Time wants you to be very worried about this: “By some estimates, the entire Greenland ice sheet would be enough to raise global sea levels 23 ft., swallowing up large parts of coastal Florida and most of Bangladesh. The Antarctic holds enough ice to raise sea levels more than 215 ft.” Farewell, Dhaka, we shall miss thee.

Or not. Those numbers sound impressive, but the chances of the ice caps’ fully melting are about as high as the chances of Time’s giving you an honest story on global warming. The truth is that there’s no solid evidence supporting the conclusion that we’ve locked the ice caps in to a melting trend. Let’s look at Antarctica and Greenland in turn.

About Antarctica, University of Virginia climate scientist Patrick J. Michaels is direct: “What has happened is that Antarctica has been gaining ice.” He explains that there has been a cooling trend over most of Antarctica for decades. At the same time, one tiny portion of the continent — the Antarctic Peninsula — has been warming, and its ice has been melting. The peninsula constitutes only about 2 percent of Antarctica’s total area, but almost every study of melting Antarctic ice you’ve heard of focuses on it.

So what about the rest of the continent? In 2002, Nature published a study by Peter Doran that looked at Antarctic temperature trends from 1966 to 2000. What it found was that about two-thirds of Antarctica got colder over that period. At the same time, Antarctica has gotten snowier, and as the snow has accumulated the ice sheet has grown. Snowfall is probably rising because water temperatures around Antarctica have gotten slightly — repeat, slightly — warmer. As a result, there is more surface evaporation, making for higher humidity and more precipitation. Higher humidity also means more clouds, which might explain the cooler weather.

How much ice has Antarctica gained? In a 2005 study published in Science, Curt Davis used satellite measurements to calculate changes in the ice sheet’s elevation, and found that it gained 45 billion tons of ice per year between 1992 and 2003. Far from flooding the coasts, that’s enough to lower sea levels by roughly 0.12 millimeters annually.

This doesn’t mean the trend of increasing Antarctic ice will continue forever. Science captured headlines in March when it published a study by Isabella Velicogna arguing that, between 2002 and 2005, Antarctica has been losing ice mass. Velicogna used a pair of satellites to measure the gravitational pull exerted by the Antarctic ice sheet, which in turn allowed her to calculate its mass. Her data suggest that, over the past three years, the sheet has lost about 152 cubic kilometers of ice per year. That would be the equivalent of about 0.4 millimeters of annual sea-level rise.

But three years do not a trend make. To begin with, such a short sampling period is a blip in the slow rhythms of climate change. Moreover, 2002 — the year in which the study began — was a high-water mark for Antarctic ice, so it’s not too surprising to see some decline since then. Alarmism over Velicogna’s study is on the order of going to the beach at high tide, drawing a line at the water’s edge, and fretting a few hours later that the oceans are drying up.

And Greenland? Various studies show that warmer temperatures are causing the ice sheet there to lose mass at the margins. But, as in Antarctica, higher sea temperatures are also causing greater snowfall and building up ice in the interior. As Richard Lindzen of MIT observes, “If you’re just going to look at what’s falling off the sides and ignore what’s collecting on top, that’s not exactly kosher.” The question is whether the net change is positive or negative.

Earlier this year, Eric Rignot and Pannir Kanagaratnam published a study in Science that used satellite measurements to calculate ice loss around Greenland’s coasts. They also used models to determine how much ice was vanishing from surface melt, and how much was accumulating from greater snowfall. Adding it all up, they got a decade of deficits: 91 cubic kilometers of ice lost in 1996, rising to 224 cubic kilometers in 2005. That translates to a sea-level rise of 0.23 millimeters in 1996 and 0.57 millimeters in 2005.

But, as the web publication CO2 Science has pointed out, their model-based estimate of the ice gain in Greenland’s interior was implausibly small. In fact, Science had earlier published a study by Ola Johannessen that used satellite measurements to determine how much the ice sheet was growing. Johannessen found that, between 1992 and 2003, it was gaining on average 5.4 centimeters of elevation per year.

That may not sound like a lot, but it adds up. Michaels, the University of Virginia professor, calculates that it amounts to about 74 cubic kilometers of ice per year. Rignot and Kanagaratnam could have subtracted that number from their estimate of coastal ice loss, which would have given them a negative total only for the past five years: 17 cubic kilometers lost in 2000, rising to 92 cubic kilometers in 2005. That would be equivalent to only 0.04 millimeters of sea-level rise in 2000 and 0.23 millimeters in 2005.

Add all the numbers from Greenland and Antarctica up, and you get a rather piddling total. In 2005, Jay Zwally of NASA published a study in the Journal of Glaciology that looked at the ice-mass changes for both Greenland and Antarctica from 1992 to 2002. He concluded that the total ice loss was equivalent to a sea-level rise of just 0.05 millimeters per year. At that rate, it would take the oceans a millennium to gain 5 centimeters, and a full 20,000 years to rise by a meter. To the hills, anyone?

A LONGSTANDING PATTERN
Granted, the Zwally study doesn’t include the last three years — years in which, according to some measurements, Antarctica has switched from gaining ice to losing it, and Greenland’s rate of loss has accelerated. But you don’t need to invoke man-made global warming to explain what’s going on.

Consider Greenland again. Yes, temperatures there are warmer than they were a decade ago. But many climate scientists think this is the result of a phenomenon called the Atlantic Multidecadal Oscillation (AMO) — a pattern of slow, repeating changes in the ocean’s surface temperatures. The AMO affects both the Atlantic tropics and the regions farther north. When the AMO is in its positive phase, temperatures rise in both places — which should cause more Caribbean hurricanes, and increase the speed at which Greenland’s glaciers discharge into the sea. This appears to be just what is happening. “The AMO changed from negative to positive in 1995,” Michaels wrote on Tech Central Station. “Since then hurricanes have become very active and glacier output has been accelerating.” Is this man’s fault? Models suggest that the AMO has been going on for at least 1,400 years. Maybe things would have turned out differently had Charlemagne signed the Kyoto Protocol, but the odds are against it.

In fact, we have temperature records indicating that Greenland was as warm as it is today during the first half of the 20th century. From 1920 to 1930, Greenland saw significant warming, and temperatures stayed high through the ’40s. A team of scientists led by Petr Chylek looked at Greenland’s temperature record in a study forthcoming from Geophysical Research Letters. They write that the increase in Greenland’s temperature between 1920 and 1930 was “of a similar magnitude” to the increase between 1995 and 2005. But the earlier warming happened faster: “The rate of warming in 1920–1930 was about 50% higher.” 2003 was a hot year, but “the years 2004 and 2005 were closer to normal[,] being well below temperatures reached in [the] 1930s and 1940s.” Moreover, “although . . . 1995–2005 was relatively warm, almost all decades within 1915 to 1965 were even warmer.”

Roman Genn

If today’s temperatures are causing Greenland’s coastal ice to slide into the sea, it must have been positively galloping there 80 years ago. That’s significant, because the warming period in the early 20th century took place well before fossil-fuel burning could have triggered global warming. So we can’t say with any confidence that what we’re seeing in Greenland today is our fault. Chylek’s team concludes its study with the observation, “We find no evidence to support the claims that the Greenland ice sheet is melting due to increased temperature caused by increased atmospheric concentration of carbon dioxide.”

As with Greenland, so with the world. There is no consensus that human activity is the main cause of climate change. Reluctant though one is to question Time’s authority in matters scientific, it’s simply wrong when it declares: “In the past five years or so, the serious debate has quietly ended. Global warming, even most skeptics have concluded, is the real deal, and human activity has been causing it.”

What we know is that the global average temperature has risen by about 1 degree Celsius or less since the late 1800s. We also know that industrial activity has raised atmospheric carbon-dioxide concentrations, and that this increase should make things warmer. But there is wide disagreement about the extent to which carbon-dioxide emissions are responsible for the warming we’ve seen so far, and how much warming they will cause in the future.

Fred Singer of George Mason University points out that “we have historic [temperature] records in Europe going back a thousand years. It was much warmer then than today. The Arctic was much warmer a thousand years ago than it is today. Polar bears survived. The ice caps survived.” And data from ice cores suggest that previous interglacial periods were warmer than the one we’re going through now.

Moreover, the models scientists use to predict the effects of carbon-dioxide emissions are biased to overpredict global warming. They assume that atmospheric concentrations of CO2 will increase by about 1 percent a year. In fact, this is more than twice the observed rate. In the last ten years, the average increase was 0.49 percent; in the decade before that, it was 0.42 percent; and in the decade before that, it was 0.43 percent. But scientists keep feeding the models 1 percent. That’s more than a 100 percent margin of error. Three cheers for precision.

It’s not surprising, then, that actual warming in recent years has been lower than the models say it should have been. By creating a false sense of alarm, the models make the ice-cap debate much shriller than it should be. For example, the authors of the Science study that Time refers to were able to predict a sea-level rise of several meters only because they took as Gospel the 1 percent–per–year CO2 increase. That gave them a tripling of atmospheric CO2 by 2100 and a quadrupling by 2130. But as Michaels points out, observed data suggest this quadrupling won’t happen till 2269. “By then,” he writes, “energy-production technology will probably have turned over two or three times and this will never have become an issue.”

THE WORSE THE BETTER
Why are scientists using the wrong numbers? Richard Lindzen of MIT thinks that, while most scientists were originally agnostic on the question whether human activity was causing global warming, “environmentalists and the media would exaggerate.” That eventually built up a public concern, and politicians responded by throwing research dollars at scientists. If global warming turned out not to be a problem, those dollars would go away. Better to keep us worried: “You’ve developed a scientific community that will do whatever it needs to do to make sure the answer isn’t obtained. Why should taxpayers pay for people not to find an answer?”

Lindzen doesn’t mean that there is a conspiracy among scientists, but rather that the funding process gives an incentive toward pessimism. If you have doubts about this, consider how frequently climate scientists tell us that things are worse than we thought. If a scientific study isn’t biased in such a way as to look for an alarming outcome, the odds that its findings will be better than expected are equal to the odds that they will be worse than expected. In other words, it’s a coin toss; an unbiased research process should produce better-than-expected results and worse-than-expected results in roughly equal proportion. Michaels got interested in this notion. He looked at a single day last December when 15 findings on global warming were released to the press. Fourteen fell into the worse-than-expected category. But if none of the studies that produced the findings was biased, the odds of getting a 14-to-1 ratio are less than 1 in 2,000.

Of course, even if man-made global warming is the primary cause of the mild temperature and sea-level rises being observed, this doesn’t settle the question of what to do about it. The environmental lobby’s answer is: Ratify the Kyoto Protocol. Time isn’t even subtle about it, calling George W. Bush’s environmental record “dismal” and specifically citing his abandonment of Kyoto. But he abandoned it for good reason. The U.S. Energy Information Administration estimates that the treaty would cost the American economy $300 billion to $400 billion a year (Lyrebird: dit wordt op Fok 'een fooi' genoemd). Any decision about whether to pay such a price should be based on cost-benefit analysis. What, then, is the benefit?

In a word, nothing. Kyoto wouldn’t stop whatever warming is caused by greenhouse-gas emissions; it would just slow it. And it would barely do that. Tom Wigley of the National Center for Atmospheric Research calculated that the full global implementation of Kyoto would prevent 0.07 degrees Celsius of global warming by 2050, an outcome that is all but undetectable. To put a dent in CO2 levels, you’d need much greater emissions reductions than Kyoto calls for. Jerry Mahlman of the National Center for Atmospheric Research, for example, has called Kyoto a “first step” and said that “30 Kyotos might do the job.”

Thirty Kyotos would also come at the price of economic collapse. When it’s not even clear that the warming we’ve seen is hurting us — many argue that it’s a boon, citing its benefits to agriculture and its potential to make severe climates more hospitable — such draconian solutions should be unthinkable. And if it turns out that carbon dioxide is hurting the planet, it’s probably doing so at such a gradual pace that the best solution is to wait for markets to produce new innovations in energy technology. (And are we finally far enough away from Three Mile Island to utter the word “nuclear”?)

In the meantime, let’s stick with what we know — about melting ice, and about global warming generally. We’re not sure that we have a problem. If we do, we don’t know that we’re the ones causing it. But Time, Al Gore, the Democratic party, the EU, politically correct scientists, and the entire green lobby want us to throw enormous sums of money at solutions that won’t work anyhow.

Good plan, guys.

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Op zaterdag 27 mei 2006 19:07 schreef Sidekick het volgende:
Het is overduidelijk dat de temperaturen een huidig hoogtepunt bereiken sinds de start van de Holoceen 10.000 jaar geleden...