A group of expert climate scientists, meeting in Stockholm have released a report which they say incontrovertibly shows that anthropogenic climate change (that is, change caused by human activity) is threatening life on this planet. The release coincides with Climate talks being held in Stockholm, at which government officials and scientists have been discussing the issue.

image expired

The UN-convened Intergovernmental Panel on Climate Change (IPCC) declared on Friday that evidence of humanity's influence on the climate system is now apparent in most global regions. The panel said more attention and better observations, alongside improvements in climate science have enabled them to conclude that, "It is extremely likely that human influence has been the dominant cause of the observed warming since the mid-20th century."

The paper is the first of three scheduled for release this year. Climate scientists hope the reports will spur action from policy makers to address the threat of climate change, which successive international talks have failed to achieve.

Reports prior to the release suggested some scientists and world leaders were concerned that an apparent slow-down in global warming since 1998 would be taken out of context and misrepresented by climate change deniers. Expert contributors to the report maintain that the observed slow-down is too short to affect long-term trends, which show that "Warming in the climate system is unequivocal and since 1950 many changes have been observed throughout the climate system that are unprecedented over decades to millennia."

Experts discuss findings

259 scientists from 39 countries delivered the report at the end of the conference in Sweden. Their studies have been reviewed by over 1,000 experts, according to IPCC chair Rajendra Pachauri. The findings, which were leaked in an earlier document, show that each of the last three decades has been successively warmer at the Earth's surface than any preceding decade since 1850, and probably warmer than any other for over 1,000 years, the panel said.

Qin Dahe, Co-Chair of an IPCC Working Group said on Friday, "Our assessment of the science finds that the atmosphere and ocean have warmed, the amount of snow and ice has diminished, the global mean sea level has risen and the concentrations of greenhouse gases have increased." Thomas Stocker, his fellow chair added, "Continued emissions of greenhouse gases will cause further warming and changes in all components of the climate system. Limiting climate change will require substantial and sustained reductions of greenhouse gas emissions."

Projections for climate change are based on a new set of four scenarios of future greenhouse gas concentrations and aerosols, spanning a wide range of possible futures. The experts warn that continued high levels of emissions could cause a chain reaction, potentially causing global warming to spiral out of control.

“Global surface temperature change for the end of the 21st century is projected to be likely to exceed 1.5°C relative to 1850 to 1900 in all but the lowest scenario considered, and likely to exceed 2°C for the two high scenarios,” Dahe said. "Heat waves are very likely to occur more frequently and last longer. As the Earth warms, we expect to see currently wet regions receiving more rainfall, and dry regions receiving less, although there will be exceptions."

"As the ocean warms, and glaciers and ice sheets reduce, global mean sea level will continue to rise, but at a faster rate than we have experienced over the past 40 years,” continued Qin Dahe. The majority of the increased energy stored in the climate system, which leads to global warming, is thought to be found in the Earth's oceans – IPCC experts believe that the seas account for 90 percent of the energy accumulated between 1971 and 2010.

Co-Chair Thomas Stocker offered the grim conclusion that, "As a result of our past, present and expected future emissions of CO2, we are committed to climate change, and effects will persist for many centuries even if emissions of CO2 stop."

Environment group Greenpeace last week released a report on climate sceptics, funded largely by companies with vested interests, who have attempted to cast doubt on climate science in a bid to support their "anti-regulatory, so called 'free market' ideology, [rather than] legitimate scientific debate." Amongst these is the NIPCC, which has been set up to produce sceptical reports, with a name bearing a deliberate similarity to the UN panel on climate change, that have do not carry scientific weight and have not been subjected to peer review.