An international team of scientists has found with near certainty that human activity is the cause of most of the temperature increases of recent decades, and warns that sea levels could rise by more than three feet by the end of the century if emissions continue at a runaway pace.
The scientists, whose findings are reported in a summary of the next big United Nations climate report, largely dismiss a recent slowdown in the pace of warming, which is often cited by climate change contrarians, as probably related to short-term factors. The report emphasizes that the basic facts giving rise to global alarm about future climate change are more established than ever, and it reiterates that the consequences of runaway emissions are likely to be profound.
This is no big surprise or anything, but nonetheless nice to see. The “slowdown” of the past decade has always been exaggerated by the climate deniers, and to the extent it exists, it’s most likely the product of a natural fluctuation between energy being absorbed by the atmosphere vs. energy being absorbed by the oceans. Right now the oceans are warming at an unusually fast rate, but when the current fluctuation turns around, global warming will continue along its inexorable path. Other possible explanations for the slowdown include volcanic eruptions offsetting some of the greenhouse warming or a lower sensitivity to greenhouse gases than most scientists think, but my money is on the oceans.
(Not that ocean warming is any consolation. Not only does it raise sea level via thermal expansion, but it does tremendous harm to the ocean ecology as well.)
Chris Mooney has a bit more on the leaked report here. And if a three-foot rise in sea level doesn’t seem like all that much, think again. Even a small rise in sea level has a huge impact on the floods caused by hurricanes. Tim McDonnell has more on that here.