Scientific consensus on global warming

The scientific opinion on climate change is the overall judgment among scientists regarding the extent to which global warming is occurring, its likely causes, and its probable consequences. The scientific consensus is that the Earth's climate system is unequivocally warming, and that it is extremely likely (meaning 95% probability or higher) that this warming is predominantly caused by humans. It is likely that this mainly arises from increased concentrations of greenhouse gases in the atmosphere, primarily from the burning of fossil fuels, partially offset by human-caused and volcanic aerosols; natural change has had little effect.

This scientific opinion is expressed in synthesis reports, by scientific bodies of national or international standing, and by surveys of opinion among climate scientists. Individual scientists, universities, and laboratories contribute to the overall scientific opinion via their peer-reviewed publications, and the areas of collective agreement and relative certainty are summarised in these respected reports and surveys. The IPCC's Fifth Assessment Report (AR5) was completed in 2014. AR5 followed the same general format as of AR4, with three Working Group reports and a Synthesis report. The Working Group I report (WG1) was published in September 2013.

Conclusions of AR5 are summarized below:

National and international science academies and scientific societies have assessed current scientific opinion on global warming. These assessments are generally consistent with the conclusions of the Intergovernmental Panel on Climate Change.

Some scientific bodies have recommended specific policies to governments, and science can play a role in informing an effective response to climate change. Policy decisions, however, may require value judgements and so are not included in the scientific opinion.

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