 changeClimate systemEffects of climate changeClimate change mitigationClimate change adaptationBy country and regionCausesOverviewAttribution of recent climate changeCarbon dioxide in Earth's atmosphereExtreme event attributionGreenhouse effectScientific consensus on climate changeSourcesGreenhouse gasesGreenhouse gas emissionsCarbon accountingCarbon footprintfrom agriculturefrom wetlandsFossil fuelDeforestation and climate changeRepresentative Concentration PathwayShared Socioeconomic PathwaysWorld energy supply and consumptionHistoryHistory of climate change scienceHistory of climate change policy and politicsSvante ArrheniusJames HansenCharles David KeelingUnited Nations conferencesYears in climate change20192020202120222023Effects and issuesPhysicalAbrupt climate changeAnoxic eventArctic methane emissionsArctic sea ice declineAtlantic meridional overturning circulationDroughtExtreme weatherFloodCoastal floodingGlacier retreatHeat wav