Humans to blame for global warming, says landmark UN report

Humans to blame for global warming, says landmark UN report

Humans to blame for global warming, says landmark UN report

A UN panel of climate change experts today announced that mankind is almost certainly to blame for global warming, warning that the planet will see increasingly extreme weather events unless governments take strong action. In a much anticipated report released Friday, the Intergovernmental Panel on Climate Change (IPCC) said it is “extremely likely” that most global warming is manmade, asserting its claims with 95 percent certainty.

“It is extremely likely that more than half of the observed increase in global average surface temperature from 1951 to 2010 was caused by the anthropogenic increase in greenhouse gas concentrations and other anthropogenic forcings together,” the report reads. “The best estimate of the human-induced contribution to warming is similar to the observed warming over this period.”

In a press conference held in Stockholm on Friday, Michel Jarraud, secretary general of the World Meteorological Organization, said the last decade was the warmest on record, attributing much of this increase to the burning of fossil fuels.

“Warming of the climate system is unequivocal.”

“Warming of the climate system is unequivocal, and since the 1950s, many of the observed changes are unprecedented over decades to millennia,” the IPCC said. “The atmosphere and ocean have warmed, the amounts of snow and ice have diminished, sea level has risen, and the concentrations of greenhouse gases have increased.”

Concentrations of climate changing gases carbon dioxide, methane, and nitrous oxide have increased to levels not seen over the previous 800,000 years, the report says, with carbon dioxide emissions increasing 40 percent since pre-industrial times. This has led to increased temperatures and rising sea levels, and the IPCC expects Arctic sea ice cover to decrease over the coming century. Mitigating these changes, the panel says, will require “substantial and sustained reductions of greenhouse gas emissions.”

The IPCC acknowledged that there has been a so-called “hiatus” in rising temperatures over the past 15 years, but said there is not sufficient data to explain this slowdown in warming rates. Thomas Stocker, co-chair of the IPCC working group, said evidence shows there is a “large amount of natural variability” in global temperatures, adding that a 15-year window is too narrow to extract significant conclusions.

“Each of the last three decades has been successively warmer at the earth’s surface than any preceding decade since 1850.”

Still, over the longer term, it is clear that the planet is warming at dramatic rates. “Each of the last three decades has been successively warmer at the earth’s surface than any preceding decade since 1850,” IPCC chairman Rajendar Pachauri told reporters.

The UN has agreed to create a plan to combat climate change by 2015.

The 36-page summary released today is the first part of the IPCC’s Fifth Assessment Report. A full report will be released on Monday, followed by three additional reports over the next year. The report, compiled by 259 scientists from 39 countries, does not include any original research, but bases its conclusion on a review of existing literature.

Comprised of 195 member nations, the IPCC is widely seen as an authoritative voice on climate change, with governments looking to its reports to guide policymaking decisions. But the panel has come under increased criticism in recent years, with climate change skeptics charging that the IPCC exaggerates its claims to make global warming seem more extreme than it is, and others claiming that the panel waters down its findings. Its last report, published in 2007, included an exaggerated claim about melting glaciers in the Himalayas, though later studies found that the mistake did not impact the panel’s larger findings.