It is extremely likely that human activities have been the dominant cause of for global warming, states the Intergovernmental Panel on Climate Change (IPCC) in the first part of the fifth assessment report, which was presented on 27 September in Stockholm. They also note that the last three decades have been the warmest compared to any other decade after 1850. In the northern hemisphere, it is very likely that the last thirty years have been the warmest in 1,400 years.
“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.
Thomas Stocker, the other Co-Chair of Working Group I said: “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.”
For the first time, the IPCC provides a global budget for CO2, which cannot be exceeded if we are to prevent devastating levels of global warming. Climate Action Network Europe notes in their press release, “since the report shows we have already blown through half our carbon budget, we must start reducing carbon emissions immediately” and then emphasises the gap between the state of knowledge and policy action, “we don’t want to see another comprehensive report on the grim realities of climate change gathering dust on politicians’ bookshelves while impacts mount”.