A UN panel has released part one of its six-yearly update on the state of the Earth’s climate. The much-anticipated report by the Intergovernmental Panel on Climate Change (IPCC) says that with 95% certainty, humans are the dominant cause of global warming since the 1950s. The BBC News website’s science editor Paul Rincon breaks down some of the document’s key findings.
Part one of the IPCC’s fifth assessment report (AR5) on the Earth’s climate opens with the message that we are seeing changes in the climate system unprecedented in records spanning hundreds of years.
With this scene-setting out of the way, the report says the period from 1983-2012 in the Northern Hemisphere was likely the warmest 30-year period of the last 1,400 years. Each of the last three decades has got successively warmer, and these decades have all been warmer than any of the preceding decades since 1850.
The combined average land and ocean surface data show a temperature rise of 0.85C over the period 1880-2012, the authors go on to say.
In addition, it is “virtually certain” that the upper 700m of the Earth’s oceans have warmed during the period from 1971 and 2010. The deep ocean, below 3,000m in depth, “likely” warmed between 1992 and 2005, says the report, with the largest warming observed in the Southern Ocean.
The report says that the Greenland and Antarctic ice sheets have been losing mass, glaciers have continued to shrink, and Arctic sea-ice as well as Northern Hemisphere spring snow cover have continued to fall in extent…
[continues at BBC News]