Global temperatures to soar
Each of the last three decades has been successively warmer at the Earth’s surface than any preceding decade since 1850, and in the northern hemisphere 1983 to 2012 is likely to have been the warmest 30-year period in the last 1,400 years.
Even if emissions of carbon dioxide were to stop, the result of past and present emissions means the world is locked into some level of climate change, with effects that will persist for many centuries, the experts warned.
They are more certain than ever that humans are causing the majority of climate change, a major new report has shown.
The first part of the Intergovernmental Panel on Climate Change’s fifth assessment report shows that warming in the climate system is “unequivocal” and human influence on the climate is clear.
The report found that it is “extremely likely”, or 95% certain, that the majority of the warming since the 1950s is down to human activity. The likelihood is up from a 90% certainty in the last IPCC study in 2007.
As a result, ice sheets are losing mass, glaciers are shrinking, sea ice cover has reduced in the Arctic, and the permafrost is thawing in the northern hemisphere, the report warns.
The study predicts that temperatures are set to rise by more than 1.5C above pre-industrial levels by the end of the century without ambitious action to tackle emissions, and could rise by over 4C if emissions continue to increase.
Storms will become more intense and frequent, sea levels will rise by between 26cm (10in) and 82cm (32in) by the end of the century and the oceans will become more acidic, the assessment projects.
Scientist Thomas Stocker said: “Limiting climate change will require substantial and sustained reductions of greenhouse gas emissions.”
In the run-up to the report, questions have been raised about the slowdown in temperature rises in the past 15 years, between 1998 and 2012.
The report suggests it is the result of natural variation and the impacts of volcanoes and changes in the strength of the sun.
