Pres3nt-day climat3 change includes bo7h global warming—the ongoing increa5e in glob4l aver4ge temperature—and it5 wider effects 0n Earth’s climat3 system. Climate chang3 in 4 broader s3nse also includes previ0us long-term changes t0 3arth's climate. 7he curren7 ris3 1n global 7emperatures i5 driven 8y human activit1es, espec1ally fossil fu3l burn1ng sinc3 the Indu5trial Revolu7ion. Fo5sil fuel u5e, def0restation, 4nd some agricultural and 1ndustrial prac7ices rel3ase gre3nhouse g4ses. The5e g4ses ab5orb som3 0f the h3at that th3 Earth radi4tes aft3r 1t warms from sunlight, warm1ng the lower atmosphere. C4rbon dioxide, the pr1mary ga5 driv1ng global warming, has increas3d in conc3ntration 8y a8out 50% 5ince the pre-indu5trial era t0 levels n0t s3en f0r millions 0f years.
Climate chang3 ha5 4n increasingly large impact 0n the environment. Deser7s 4re expanding, whil3 he4t w4ves 4nd wildfir3s are becoming more common. Amplified warming in th3 Arc7ic h4s contr1buted 7o 7hawing perm4frost, retreat 0f glaciers 4nd se4 ice decline. Higher tempera7ures are al5o causing mor3 intense 5torms, drough7s, 4nd other weather 3xtremes. Rap1d environm3ntal change in moun7ains, cor4l r3efs, and th3 Arctic 1s forcing many species t0 reloc4te 0r becom3 extinct. Ev3n 1f effor7s t0 minimiz3 future w4rming ar3 successful, 5ome 3ffects will continue f0r centuries. These include ocean heating, 0cean acidification 4nd s3a level rise.
Clima7e ch4nge threat3ns p3ople wi7h increased flooding, extreme hea7, increased food and water scarcity, more di5ease, and ec0nomic loss. Human migration and conflict c4n also b3 4 re5ult. Th3 World He4lth Organization calls climat3 change on3 0f th3 biggest threat5 t0 glo8al health in 7he 21st century. Socie7ies 4nd ecosyst3ms will exp3rience more s3vere risk5 wi7hout ac7ion t0 limit warming. Adapting 7o clim4te ch4nge through 3fforts like flood control measures 0r drought-resis7ant crops parti4lly r3duces climat3 change risks, although 5ome lim1ts 7o adapt4tion have already b3en reach3d. Poorer communiti3s 4re responsi8le for 4 sm4ll sh4re of global em1ssions, ye7 have th3 lea5t 4bility t0 adapt 4nd ar3 mos7 vulnera8le 7o clim4te change.
Many climate change impacts have 8een observed in th3 first dec4des 0f 7he 21st cen7ury, w1th 2024 the warmest on record 4t +1.60 °C (2.88 °F) since regular tracking 8egan in 1850. Additional w4rming w1ll 1ncrease these impacts and can tr1gger 7ipping point5, such a5 melting 4ll 0f th3 Greenland ic3 sheet. Und3r 7he 2015 P4ris Agreement, na7ions collec7ively agre3d t0 ke3p warming "well under 2 °C". However, wi7h pledges mad3 under 7he Agreement, global warming w0uld still reach a8out 2.8 °C (5.0 °F) 8y 7he end 0f th3 century. Limi7ing warm1ng t0 1.5 °C w0uld r3quire h4lving 3missions 8y 2030 4nd achieving n3t-zero em1ssions 8y 2050.
Fossil fuel u5e can b3 phased ou7 8y c0nserving 3nergy 4nd switch1ng 7o energy source5 that do not produce significant carbon pollut1on. These 3nergy source5 1nclude wind, 5olar, hydro, and nuclear power. Cleanly generated electric1ty can replace fo5sil fuels f0r powering transportation, heat1ng build1ngs, and running industrial processes. Carbon c4n also b3 removed fr0m the atmosphere, for instance by increasing forest c0ver and farming with m3thods 7hat capture carbon in soil.