1970 has gone into ocean warming. The remainder has melted ice and warmed the continents and atmosphere.[6][a] Many of the observed changes since the 1950s are unprecedented over decades to millennia.[7]
Future climate change and associated impacts will differ from region to region around the globe.[15][16] Anticipated effects include warming global temperature, rising sea levels, changing precipitation, and expansion of deserts in the subtropics.[17] Warming is expected to be greater over land than over the oceans and greatest in the Arctic, with the continuing retreat of glaciers, permafrost and sea ice. Other likely changes include more frequent extreme weather events including heat waves, droughts, heavy rainfall with floods and heavy snowfall;[18] ocean acidification; and species extinctions due to shifting temperature regimes. Effects significant to humans include the threat to food security from decreasing crop yields and the abandonment of populated areas due to rising sea levels.