IPCC AR5 WG I Report "The Physical Science Basis"
Contribution of Working Group I to the IPCC 5th assessment report (AR5)
“Climate Change 2013: The Physical Science Basis” presents clear and robust conclusions in a global assessment of climate change science - not the least of which is that the science now shows with 95 percent certainty that human activity is the dominant cause of observed warming since the mid-20th century.
The report confirms that warming in the climate system is unequivocal, with many of the observed changes unprecedented over decades to millennia: warming of the atmosphere and the ocean, diminishing snow and ice, rising sea levels and increasing concentrations of greenhouse gases. Each of the last three decades has been successively warmer at the Earth’s surface than any preceding decade since 1850.
These and other findings confirm and enhance our scientific understanding of the climate system and the role of greenhouse gas emissions; as such, the report demands the urgent attention of both policymakers and the general public.