An article by Bill McKibben in the New York Review of Books, “Warning on Warming,” gives background on the process that led to the formation of the Intergovernmental Panel on Climate Change, provides a precis of the report issued this February, and discusses the current political state of play.
McKibben stresses that most media stories on the recent report has downplayed its findings, that the document itself is conservative (that is, it limits its commentary to issues where scientists have a high degree of certainty) and due to research and preparation lag times, recent data pointing to a worsening situation (the faster-than-expected melting of the Greenland and Antarctic ice shelves) were not incorporated (the latter has been noted in some US articles).
All of this, of course, implies the situation is more urgent than has been widely portrayed. From McKibben:
The finding of the new report that attracted the most attention in the press was that scientists were now more confident than ever that the warming we’ve seen so far (about one degree Fahrenheit in the average global temperature) was caused by human beings. Instead of being merely “likely,” the conclusion was now “very likely,” which in the IPCC’s lexicon means better than a 90 percent chance. But it’s been years since any reputable scientist specializing in climate research doubted that conclusion. More important findings were ignored in accounts of the report and in some cases were obscured by the document’s very poor prose, which is much more opaque than its predecessors. Those findings include:
* The amount of carbon in the atmosphere is now increasing at a faster rate even than before.
* Temperature increases would be considerably higher than they have been so far were it not for the blanket of soot and other pollution that is temporarily helping to cool the planet.
* Alternative explanations for some of the warming (for example, sunspot activity and the “urban heat island effect,” the raising of temperatures in cities caused by high building densities and the use of heat-retaining materials such as concrete and asphalt) are now known to be relatively negligible.
* Almost everything frozen on earth is melting. Heavy rainfalls are becoming more common since the air is warmer and therefore holds more water than cold air, and “cold days, cold nights and frost have become less frequent, while hot days, hot nights, and heat waves have become more frequent.”
These facts serve as the prelude to the most important part of the new document, its predictions for what is to come. Here too the news essentially confirms the previous report, and indeed most of the predictions about climate change dating back to the start of research: if we don’t take the most aggressive possible measures to curb fossil fuel emissions immediately, then we will see temperature increases of— at the best estimate—roughly five degrees Fahrenheit during this century. Technically speaking, that’s enormous, enough to produce what James Hansen has called a “totally different planet,” one much warmer than that known by any of our human ancestors.
The process by which the IPCC conducts its deliberations—scientists and national government representatives quibbling at enormous length over wording and interpretation—is Byzantine at best, and makes the group’s achievements all the more impressive. But it sacrifices up-to-the-minute assessment of data in favor of lowest-common-denominator conclusions that are essentially beyond argument. That’s a reasonable method, but one result is that the “shocking” conclusions of the new report in fact lag behind the most recent findings of climate science by several years.
That’s most obvious here in the discussion of the rise in sea level. Researchers know that sea levels will rise fairly quickly this century, in part because of the melting of mountain glaciers and in part because warm water takes up more space than cold. The new assessment refines the calculations of the rise in sea level and puts the best estimate at a foot or two, which is actually slightly less than the last assessment in 2001. Though it doesn’t sound like much, a couple of feet is actually a large amount— enough to inundate many low-lying areas and drown much of the earth’s coastal marshes and wetlands. Still, it might be more or less manageable.
During the last eighteen months, however, new research has indicated that a far more rapid rise in sea level may be possible, because the great ice sheets of Greenland and the Antarctic appear to have begun moving more quickly toward the sea….But it is not included in the IPCC report, except as a caveat: “larger values cannot be excluded, but understanding of these effects is too limited to assess their likelihood or provide a best estimate or an upper bound for sea level rise.”….
Even using its conservative projections, the panel states unequivocally that typhoons and hurricanes will likely become more intense, that sea ice will shrink and perhaps disappear in the summertime Arctic, that snow cover will contract….
Because of the time lag between carbon emissions and their effect on air temperature, even if we halted the increase in coal, oil, and gas burning right now, temperatures would continue to rise about two tenths of a degree Celsius per decade. But, the report writes, “if all radiative forcing agents [i.e., greenhouse gases] are held constant at year 2000 levels, a further warming trend would occur in the next two decades at a rate of about 0.1ºC per decade.”
Translated into English, this means, to put it simply, that if world leaders had heeded the early warnings of the first IPCC report, and by 2000 had done the very hard work to keep greenhouse gas emissions from growing any higher, the expected temperature increase would be half as much as is expected now. In the words of the experts at realclimate.org, where the most useful analyses of the new assessment can be found, climate change is a problem with a very high “procrastination penalty”: a penalty that just grows and grows with each passing year of inaction.