Scientists say they are 95% certain that humanity is responsible for climate change

BMJ 2013; 347 doi: (Published 27 September 2013) Cite this as: BMJ 2013;347:f5888
  1. Nigel Hawkes
  1. 1London

The role of humans in climate change is more certain than ever, concludes a new scientific assessment from the Intergovernmental Panel on Climate Change.

Despite a pause since 1998 in rises in global temperature, the panel’s report for policy makers summarising the current state of scientific knowledge is 95% certain that the rise detected over the longer term is the result of human activity—up from 90% certain in 2007.1 Warming of the climate system is “unequivocal,” the report says, with changes since the 1950s “unprecedented over decades to millennia” and each of the past three decades successively warmer than any decade since the 1850s.

The report concedes that the climate models on which its projections were based cannot explain why temperatures have not risen since 1998 but argues that people …

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