The Summary for Policymakers of the IPCC Fifth Assessment Report was released on the 27th of September 2013. This document stated that warming of the climate system is unequivocal and many associated impacts have occurred since 1950.
A total of eight hundred thirty-one experts were drawn from fields including meteorology, physics, oceanography, statistics, engineering, ecology, social sciences and economics. About thirty percent of these authors came from developing countries or economies in transition.
Working Group Two published its report on the 31st of March 2014 regarding impacts, adaptation strategies and vulnerability. The report detailed how different regions face varying degrees of risk based on their current vulnerabilities and urged governments to take action.
Projections suggest an increase in global mean temperature in 2022 of three point seven to four point eight degrees Celsius relative to pre-industrial levels. Current trajectory of global annual and cumulative emissions of greenhouse gases is not consistent with widely discussed goals of limiting global warming at one point five to two degrees Celsius above the pre-industrial level.
Climate models performed simulations for various Representative Concentration Pathways reaching specific carbon dioxide concentrations by the year 2022. These pathways included RCP2.6, RCP4.5, RCP6.0, and RCP8.5 representing different emission futures.