Global warming is real and human beings are responsible: IPCC - Economic Times

NEW DELHI: Scientists are saying with extreme confidence that human activity is the main cause of the global warming observed since the 1950s, according to the report released by the UN sponsored scientific body, the Intergovernmental Panel for Climate Change.

In its strongest articulation yet, the IPCC said that its "extremely likely" that more than half of the increased global temperatures between 1951 and 2010 was due to human activity. This is a significant upgrade from the 2007 assessment, when the IPCC had said it was "very likely" that global warming was man-made.

The scientific assessment drives home the need for immediate and aggressive action to reduce carbon emissions. It states that if temperature rise is to be contained to the guardrail of 2 degrees set by science to limit adverse impacts of climate change then the maximum permissible emissions would be to the tune of 880 giga tonnes of carbon. The report states that already, 531 gigatonnes of carbon of the total permissible limit has been emitted by 2011.

The report finalised after a week-long discussion by representatives of 195 countries and scientists stressed that more and better observations, improved understanding of the climate system response and improved climate models has meant that evidence of human influence in global warming has "grown since the 2007 Fourth Assessment Report."

"Observations of changes in the climate system are based on multiple lines of independent evidence. 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," said Qin Dahe, Co-Chair of IPCC Working Group I.

The report uses four emission scenarios to project a rise of 0.3 degrees Centigrade to 4.8 degrees Centigrade in global temperatures by the end of the century. The scenario projecting a lower temperature rise requites significant emission reduction by countries. The report has raised its projections of the rise in sea levels to 26-82 cm by the end of the century.

The key findings, referred to as the Summary for Policy makers, of first of the three parts of the IPCC's Fifth Assessment Report was released in Stockholm on Friday. "This Working Group I Summary for Policymakers provides important insights into the scientific basis of climate change. It provides a firm foundation for considerations of the impacts of climate change on human and natural systems and ways to meet the challenge of climate change," IPCC chairman RK Pachauri said.

The IPCC assessment report is important as it provides a scientific basis and gives key direction to governments in the global negotiations and domestic policy formulations. Friday's report will feed into the UN-sponsored climate change negotiations to be held in Warsaw in November, where representatives of governments will negotiate to formulate a new global regime to counter climate change.

The IPCC's strong signal about the human role in global warming and the impending rise in temperatures, has been picked up by some governments to push for stronger action at the Warsaw "The issue is not whether to believe in climate change or not. The issue is whether to follow science or not. The day when all scientists with 100% certainty warn you against climate change, it will be too late. If your doctor was 95% sure you had a serious disease, you would immediately start looking for the cure. Why should we take bigger risks when it's the health of our planet at stake?" asked EU Climate Action Commissioner Connie Hedegaard.

Climate activists hope to push governments to take a cue from science during the Warsaw negotiations in November. "Make no mistake: the underlying science of climate change is settled. The latest IPCC report confirms our overwhelming understanding that climate change is here and it's advancing even faster than we realized. Human activities are at the core of it. We can parse the details and have a rational discussion about solutions, but we ignore these scientific warnings at our own peril," said Andrew Steer of the Washington-based think tank World Resources Institute.

The report is likely to give impetus to developing countries to push on resolving the question of equity. "For the first time, the IPCC gives a global budget for the total amount of carbon pollution that cannot be exceeded if we are to meet the international goal of limiting temperature rise to 2 degrees above pre-industrial levels. What must be noted is that polluters have already burnt through of half of the budget and without equitable allocations and concrete actions by governments the aim of poverty eradication will remain unachieved when the entire budget is exhausted," said Sanjay Vashisht, director of Climate Action Network South Asia

Calling on government to act decisively, Saleemul Huq of the IIED and coordinating lead author in Working Group II of the IPCC said, "political inertia and powerful vested interests that have dominated media narratives for decades, they are less aware of the links between these impacts and their carbon emissions. Climate change affects us all and we must tackle it together. The time has come for global solidarity."

- Warming of the climate system is unequivocal—globally averaged combined land and ocean surface temperature shows a warming of 0.85 degrees between 1880 and 2012. - The period between 1983 and 2012 was likely the warmest 30-year period of the last 1400 years. - Slowdown in the rate of warming in the 15-year period between 1998 and 2012 doesn't reflect long-term climate trends. - Global mean surface temperature change between 2016 and 2035 will be between 0.3 degree and 0.7 degree more than the change between 1986 to 2005. - 99% probability that more frequent hot and fewer cold temperature extremes. - 90% probability that heat waves will occur with higher frequency and duration. - Concentration of greenhouse gases increased since 1750 due to human activity—carbon dioxide exceeds 40%, methane by 150% and nitrous oxide by 20% above pre-industrial levels. - Annual carbon dioxide emission from fossil fuel combustion and cement production averaged 8.3 gigatonne of carbon every year between 2002 and 2011. - 99% probability that global mean sea level will continue to rise beyond 2100. Sea level rise between 2081 and 2100 is projected to be in the range of 0.26m to 0.98m.

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