（2014-11-03）The report released in Copenhagen on Sunday sends a clear message to governments that failure to check climate change by allowing the continued rise in emissions of greenhouse gases will have disastrous consequences.
"The scientific case for prioritising action on climate change is clearer than ever... Beyond a certain point, human society cannot cope with the change, and therefore, the IPCC has drawn up a very clear rationale for the society to deal with this problem," IPCC Chairman RK Pachauri said.
The report, which distils and integrates the findings of the three working groups comprising the Fifth Assessment Report and two special reports brought out by the IPCC in 2011, stresses on the need to tackle climate change urgently through a combination of adaptation and mitigation.
"We have little time before the window of opportunity to stay within 2oC of warming closes. To keep a good chance of staying below 2oC, and at manageable costs, our emissions should drop by 40 to 70% globally between 2010 and 2050, falling to zero or below by 2100. We have that opportunity, and the choice is in our hands," Pachauri said.
UN Secretary-General Ban Kimoon, who was present in Copenhagen, said, "Science has spoken. There is no ambiguity in their message. Leaders must act. Time is not on our side."
The report, experts say, breaks new ground by addressing ways in which countries may address emission reduction by an integrated approach to policy making and focusing on co-benefits.
"The IPCC synthesis report suggests a way of thinking about climate change that is deeply relevant to India. There is a complex two-way relationship between sustainable development and climate change: climate policies should support, not undermine, sustainable development; but limiting the effects of climate change is necessary to achieve sustainable development. This suggests India has to increasingly internalise climate considerations into development planning," said Navroz Dubash, lead author on national and sub-national policies for the IPCC report and senior fellow at the Centre for Policy Research.
The IPCC report states that the levels of three key greenhouse gases - carbon dioxide (CO2), methane and nitrous oxide - are the highest in 800,000 years and that the period between 1983 and 2012 were most likely to be the warmest 30-year period in the last 1,400 years. It also states that increased oceanic uptake of carbon dioxide has resulted in a 26% rise in acidity in oceans.
The report doesn't shy away from the fact that there is a cost to ensuring that the global temperature increase is limited to under 2 degrees above pre-industrial levels by the end of the century. It stresses that this cost is both affordable—about 0.06% of GDP every year—especially as global GDP is set to grow by at least 300% in this period and that the cost of inaction is much higher than the cost of action.