More than ever, scientists say they’re convinced the Earth’s climate is warming. Yet lawmakers are struggling to do anything about it because the pace of change has unexpectedly slowed.
The data has caused a United Nations panel to lower predictions of the pace of global temperature increases by 2100, according to draft documents obtained by Bloomberg ahead of publication due on Sept. 27. Still, the most complete assessment of climate science in six years also is likely to conclude that melting ice will make sea levels rise faster than previously projected.
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. Skeptics have succeeded in “confusing the public,” said Michael Jacobs, who advised the U.K. government on climate policy until 2010.
“It’s been a very organized campaign by climate skeptics, using the very, very tiny number of scientists who don’t agree with the almost unanimous view of everybody else and inflating small uncertainties into apparently major challenges to the scientific consensus,” Jacobs said. “One of the challenges of the panel this year is to convince the media, politicians and the public that there is this extraordinarily widespread consensus on the major facts about climate change.”
Jacobs is now an adviser to the Institute for Sustainable Development and International Relations in Paris, which is advising the French government as it prepares for climate treaty talks in Paris in 2015.
The report identifies volcanic eruptions, a periodic decline in the sun’s warmth and natural variation in the weather as possible contributors to the lull in the overall pace of climate change, though computer models aren’t able to simulate the temperatures that have been observed.
“We don’t really know yet what the explanation is for the slowdown,” said Bob Ward, policy director at the Grantham Research Institute on Climate Change and the Environment at the London School of Economics. “The most favored explanation at the moment is that more of the heat absorbed by the oceans is being sucked down into deeper waters than before.”
Spanning thousands of pages, the report was written by 830 scientists. A summary is due Sept. 27 in Stockholm from the Intergovernmental Panel on Climate Change, an organization set up by the UN to compile research into something policymakers can assess. Further installments are due in March and April, with a final summary in October 2014.
“This knowledge is based on millions of measurements in the atmosphere, in the ocean, on land and ice,” Thomas Stocker, a professor at Switzerland’s University of Bern who led work on the first part of the report told reporters in Stockholm today. “Because this change threatens our primary resources, land and water, in short, because it threatens our only home, we must face this challenge.”
The research will guide envoys from more than 190 nations seeking to write a treaty in 2015 that would take effect in 2020, adding to greenhouse gas limits set out in the Kyoto Protocol.
Drafts of the report indicate the IPCC will find it’s “extremely likely” that humans caused more than half of the global temperature increase since the 1950s. That’s more certain than the 2007 report, which put the probability at “very likely.” The language assigns numerical probabilities of at least 95 percent for “extremely likely” and greater than 90 percent for “very likely.”
Jonathan Lynn, a spokesman for the panel declined to comment, because the report is unfinished. The draft document also:
* Refers to a slowdown in the rate of warming since 1998. Global average temperatures are likely to rise by 0.3 degree to 4.8 degrees Celsius (0.5 to 8.6 degrees Fahrenheit) by 2100, according to a draft issued on Aug. 12. That’s less than the 1.1-to 6.4-degree gain forecast in 2007. The world already has warmed about 0.89 degree since the industrial revolution.
* Says sea levels may increase 26 centimeters to 81 centimeters (10 to 32 inches) by the end of the century, more than the 2007 range for gains of 18 to 59 centimeters. The level already has risen about 19 centimeters.
* Signals that the sensitivity to a hypothetical doubling of carbon dioxide in the atmosphere may be lower, leading to a temperature increase of 1.5 to 4.5 degrees. That’s a half degree lower at the bottom end of the range than in 2007.
When the panel finished its last work six years ago, it was rewarded with the Nobel Peace Prize and the prospect its findings might spur a globally binding treaty to cut greenhouse gases. That deal never materialized, and the scientists took a battering over inaccuracies in their work and the content of leaked e-mails between climate researchers.
“The credibility and the reputation of the IPCC definitely suffered,” Professor Robert Stavins, director of Harvard University’s Environmental Economics Program said by phone from Cambridge, Massachusetts.
The latest report isn’t likely to heavily influence policy in China and the U.S., which account for more than 40 percent of global emissions from burning fossil fuels. In the U.S., lawmakers tend to use science from the report either as a “lightbulb” to illuminate discussions or a “rock” -- ammunition to defend a position, Stavins said.
“In the highly polarized political environment we have in the U.S. Congress, lamentably it’s the case that science is used as a rock and not a light bulb,” Stavins said. “It does not change people’s minds.”
For China, “its own national assessment and the level of mounting public concern about air pollution are more influential,” said Barbara Finamore, Asia director at the New York-based Natural Resources Defense Council.
Big businesses from oil company Exxon Mobil Corp. to food producer Nestle SA are starting to anticipate limits on carbon emissions, preparing for the day when policymakers act.
That IPCC’s 2007 study “provided a powerful driver for increased business and policy attention to this issue,” said Nick Robins, head of the Climate Change Center at HSBC Holdings Plc in London.
HSBC charted 157 new climate policies worldwide implemented in 2008 and 2009. The non-governmental Carbon Disclosure Project this month said 84 percent of 500 of the world’s largest companies have emissions targets. That compares with 42 percent of respondents in its 2006 survey.
“The more we understand these risks, the more pressure there is for a political response,” said Richard Gledhill, head of climate change at PricewaterhouseCoopers LLP. “Businesses are facing not just physical risks but also potentially regulatory risks.”
Leaks from the report have provided fodder for blogs and newspapers questioning whether the planet is warming at all.
The Australian newspaper on Sept. 16 published an article headlined “We got it wrong on warming, says IPCC,” a day after the U.K.’s Daily Telegraph had a story announcing “Top Climate Scientists Admit Global Warming Forecasts Were Wrong.”
In a Sept. 8 article whose headline included the words “now it’s global COOLING!,” the Daily Mail said the IPCC was forced to call a “crisis meeting.” The IPCC issued a press release denying the claim.
The stories are part of a trend toward skepticism about climate change that gained ground since the IPCC’s 2007 report. Skeptics including Marc Morano, former spokesman for Republican Senator James Inhofe, pounced on errors by the IPCC in 2007 that exaggerated the rate glaciers in the Himalayas are melting and overstated flood risks in the Netherlands.
A subsequent probe by the Amsterdam-based InterAcademy Council recommended management and structure changes. The IPCC since has largely followed those suggestions, although Chairman Rajendra Pachauri kept his post. Three “climategate” probes into leaked e-mails at the U.K.’s University of East Anglia largely exonerated scientists.
This year’s report “is less about mind-blowing new discoveries and more about getting more certainty and detail,” said Kaisa Kosonen senior political adviser on climate to the environmental group Greenpeace International.
“This is not just another piece of paper,” Jacobs said. “It will be read by politicians. They will absolutely absorb what it says. It will be without question the most significant document that has come out in this field since 2007.”