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IPCC Roundup: Early Reports Focus on Warming ‘Hiatus’

A key portion of the long awaited Fifth Assessment Report from the U.N. Intergovernmental Panel on Climate Change is slated to be released on Friday in Stockholm, where scientists and government representatives are currently meeting to finalize the report’s language. In addition to our original reporting and analysis, each day this week Climate Central will be providing a rundown on the best of news that is being reported elsewhere regarding the IPCC report.

Global-mean temperature (ºC) and CO2 (ppm) for 1971-2012.Temperature is represented in terms of deviation from 1980-1999 average. Both are based on annual mean values.The temperature for the hiatus period is highlighted.
Click image to enlarge. Credit: Scripps Institution of Oceanography.

Much of the early news has focused on the so-called global warming "hiatus" and how the document will treat the slowdown in the rate of global warming that has taken place during the past decade. Recent studies, some of which did not make it to publication until after the IPCC’s cutoff deadline of March 15, 2013, have pointed to a variety of possible causes. Some have to do with natural sources of climate variability, such as sea surface temperatures in the Pacific Ocean. Others concern manmade and natural emissions of particles that can temporarily cool the climate.

According to the BBC, many of the governments that weigh in on the wording of the report’s Summary for Policymakers, which is the most intensely scrutinized and widely-read part of the report, “are demanding a clearer explanation” for the warming slowdown than what was contained in report drafts.

“. . . This week, when the scientists will go through their summary line by line with officials from 195 governments, the pause is likely to be the focus of heated debate,” the BBC reported.

Bloomberg News suggests that the recent global warming slowdown poses a significant hurdle for scientists and policymakers seeking to raise awareness and promote action on global warming, since it introduces confusion about whether the globe is, in fact, warming. “The findings muddy the picture about how much carbon dioxide output is affecting the climate, giving ammunition to those who doubt the issue needs urgent action,” Bloomberg said.

Monte Morin of the Los Angeles Times also examined the global warming slowdown, playing up the possibility of a “heated debate” between report authors over what to say about it. “For the general public, the existence of the hiatus has been difficult to reconcile with reports of record-breaking summer heat and precedent-setting Arctic ice melts,” Morin wrote. “At the same time, those who deny the tenets of climate change science — that the burning of fossil fuels adds carbon dioxide and other greenhouse gases to the atmosphere and warms it — have seized on the hiatus, calling it proof that global warming isn't real.”

Meanwhile, a story in The Guardian contained this sobering statistic, taken from the draft report, that “humanity has emitted about half a trillion tonnes of carbon by burning fossil fuels over the past 250 years, a process that has caused atmospheric carbon dioxide levels to rise by 40 percent. The world is now on target to release another half trillion tonnes in the next few decades, which could trigger a major jump in global temperatures.”

In addition, the Yale Forum on Climate Change and the Media has put together a helpful list of background reading ahead of the report’s publication. Those articles include a deep-dive into the issue of how sensitive the climate system is to increasing amounts of carbon dioxide, a key question dealt with in a section of the report that will be released on Friday.

The report's release will only include the contribution from the first working group of the IPCC, with two more working groups slated to publish their analyses into 2014, including a report on options to reduce and adapt to the impacts of global warming.

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