Editing IPCC:AR6/WGI/Chapter-Atlas (section)

==== Atlas.10.1.2 Findings From Previous IPCC Assessments ====

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The AR5 noted observed temperature increases of 0.1°C–0.2°C per decade in the Pacific Islands and that warming was ''very likely'' to continue across all Small Islands regions ( [[#Christensen--2013|Christensen et al., 2013]] ; [[#IPCC--2013a|IPCC, 2013a]] ). It also reported decreased rainfall over the Caribbean, increases over the Seychelles, streamflow reductions over the Hawaiian Islands and projections of reduced rainfall over the Caribbean and drier rainy season for many of the south-west Pacific Islands ( [[#Christensen--2013|Christensen et al., 2013]] ; [[#IPCC--2013a|IPCC, 2013a]] ; [[#Nurse--2014|Nurse et al., 2014]] ). The remaining findings are derived from the SROCC ( [[#IPCC--2019a|IPCC, 2019a]] ). Ocean warming rates have ''likely'' increased in recent decades with marine heatwaves increasing and ''very likely'' to have become longer-lasting, more intense and extensive as a result of anthropogenic warming. Open ocean oxygen levels have ''very likely'' decreased and oxygen minimum zones have ''likely'' increased in extent. There is ''very high confidence'' that global mean sea level rise has accelerated in recent decades which, combined with increases in tropical cyclone winds and rainfall and increases in extreme waves, has exacerbated extreme sea level events and coastal hazards ( ''high confidence'' ). It is ''virtually certain'' that during the 21st century, the ocean will transition to unprecedented conditions with further warming and acidification ''virtually certain'' , increased upper ocean stratification ''very likely'' and continued oxygen decline ( ''medium confidence'' ). There is ''very'' ''high confidence'' that marine heatwaves and ''medium confidence'' that extreme El Niño and La Niña events will become more frequent. It is ''very likely'' that these changes will be smaller under scenarios with low greenhouse gas emissions. Global mean sea level will continue to rise and there is ''high confidence'' that the consequent increases in extreme levels will result in local sea levels in most locations that historically occurred once per century occurring at least annually by the end of the century under all RCP scenarios ( ''high confidence'' ). In particular, many small islands are projected to experience historical centennial events at least annually by 2050 under RCP2.6 and higher emissions. The proportion of Category 4 and 5 tropical cyclones, and associated precipitation rates and storm surges, along with average tropical cyclone intensity are projected to increase with a 2°C global temperature rise, thereby exacerbating coastal hazards.

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