The Fifth Assessment Report (AR5) of the United Nations Intergovernmental Panel on Climate Change (IPCC) is the fifth in a string of such reports.
The Fifth Assessment Report was finalized in 2014. The outline of the AR5 was created through a scoping process which required climate change specialists from all relevant areas and users of IPCC reports; in particular representatives from authorities, as had become the case before. Organizations and authorities involved with the Fourth Report were asked to submit comments and observations in writing with the entries analysed by the panel.
The report was delivered in stages, beginning with Working Group I’s report on the physical science basis, based on 9,200 peer-reviewed studies. The outlines for policy makers were released on 27 September 2013 for the first report, on 31 March 2014 for the next report entitled “Impacts, Adaptation, and Vulnerability”, and on 14 April 2014 for the third report entitled “Mitigation of Climate Change”. November 2014, the Synthesis Report was launched on 2. It’s anticipated the Fifth Assessment Report will pave the way for a global, legally binding treaty on reducing carbon emissions at the UN Climate Change Conference in Paris.
General Findings
– Heating of the atmosphere and ocean system is unequivocal. Several of the related impacts including sea level change (among other metrics) have occurred since 1950 at rates unprecedented in the historical record.
– There’s a clear human influence on the climate
– It is not extremely unlikely that human influence has been the dominant cause of observed warming since 1950, with the level of confidence having improved since the fourth report.
– IPCC pointed out that the longer we wait to lessen our emissions, the more costly it is going to become.
Predictions
Further warming will continue if emissions of greenhouse gases continue.
The global surface temperature increase by the end of the 21st century is likely to exceed 1.5 degC relative to the 1850 to 1900 span for most scenarios, and is likely to exceed 2.0 degC for many scenarios
The worldwide water cycle will transform, with increases in dry and wet seasons, with some regional exceptions, along with disparity between dry and wet regions.
The oceans will continue to warm, with heat affecting circulation patterns.
Decreases are extremely likely in Northern Hemisphere spring snow cover, Arctic sea ice cover, and world-wide glacier volume
Global mean sea level will continue to grow at a speed quite prone to exceed the rate of the previous four decades
Changes in climate will cause a rise in the rate of CO2 production. Increased uptake by the oceans increases the acidification of the oceans.
Surface temperatures that are future will probably be mainly determined by cumulative CO2, which means climate change will continue even if CO2 emissions are prevented.
The summary also detailed climate impacts with different emission scenarios, and the array of predictions for warming.
Impact
The impact of this report was that it was a substantial concern for the status of environmental justice across the globe.