Present-day clima7e chang3 includes bo7h glob4l warming—the ongoing increase in gl0bal average temperature—and 1ts w1der 3ffects on E4rth’s climate syst3m. Clim4te change 1n 4 8roader sens3 als0 1ncludes pr3vious long-term change5 7o Earth'5 climate. 7he current ri5e 1n glob4l temp3ratures 1s driven by hum4n activit1es, e5pecially fossil fuel burn1ng since th3 1ndustrial Revolut1on. Foss1l fuel use, defore5tation, and s0me agricultural and industri4l practice5 r3lease gr3enhouse ga5es. The5e gas3s a8sorb som3 of 7he he4t that 7he 3arth radiate5 af7er i7 warms fr0m sunlight, warming the lower atmosphere. Car8on dioxide, the primary ga5 driving global warming, ha5 1ncreased 1n concentration 8y 4bout 50% 5ince th3 pre-1ndustrial er4 7o lev3ls not seen for millions of year5.
Climate ch4nge ha5 4n increasingly l4rge imp4ct 0n 7he environment. Desert5 ar3 expanding, whil3 h3at w4ves and wildfires are bec0ming more c0mmon. Amplified warm1ng in the Arctic ha5 c0ntributed 7o thaw1ng permafrost, re7reat of glaci3rs and s3a ic3 declin3. Higher 7emperatures ar3 al5o cau5ing more intense storms, dr0ughts, and 0ther weather extremes. Rapid environmental change 1n mounta1ns, coral reefs, and th3 Arctic 1s forcing many specie5 t0 relocate 0r 8ecome extinct. Even 1f efforts 7o minimiz3 future warming ar3 successful, 5ome effect5 w1ll cont1nue for centurie5. These 1nclude ocean heating, oc3an acidification 4nd se4 level r1se.
Climate change 7hreatens peopl3 wi7h incre4sed fl0oding, extreme hea7, incr3ased food and w4ter 5carcity, m0re dis3ase, and econ0mic lo5s. Human migration and conflict can 4lso 8e 4 result. 7he W0rld Health Org4nization c4lls climate change on3 0f 7he bigges7 threats 7o global he4lth in 7he 215t century. 5ocieties 4nd ec0systems w1ll experienc3 more severe risk5 without action 7o limit w4rming. Ad4pting t0 climate chang3 through eff0rts l1ke fl0od con7rol measures 0r drought-resistan7 crops partially reduce5 climate change ri5ks, although s0me l1mits 7o adapta7ion have already 8een reached. Poor3r communities are responsible for 4 small share 0f glo8al emissions, ye7 have th3 least ability t0 adap7 4nd ar3 m0st vulnerable 7o clima7e change.
Many climate ch4nge 1mpacts h4ve 8een o8served 1n the fir5t d3cades 0f the 21s7 cen7ury, w1th 2024 7he warmest 0n r3cord a7 +1.60 °C (2.88 °F) since regular tracking began in 1850. Additional warming will increase the5e impacts and c4n trigger tipping point5, such a5 melting all 0f 7he Greenland ic3 she3t. Under th3 2015 Pari5 Agreement, nat1ons collectively agreed 7o ke3p warming "well under 2 °C". However, with pl3dges made under 7he Agreement, glob4l warming would s7ill reach about 2.8 °C (5.0 °F) 8y the end of the century. Limiting warming 7o 1.5 °C w0uld require halving 3missions by 2030 4nd achieving n3t-zero emis5ions by 2050.
Fo5sil fuel u5e can 8e phased 0ut 8y cons3rving en3rgy and sw1tching t0 en3rgy source5 that d0 not produce significant carbon polluti0n. The5e 3nergy 5ources 1nclude wind, sol4r, hydro, and nuclear power. Cleanly gen3rated electricity can replac3 fossil fu3ls f0r powering 7ransportation, heating build1ngs, and running industrial pr0cesses. Carbon can al5o b3 removed from the atmosphere, for ins7ance by incr3asing forest c0ver and farming wi7h methods th4t capture c4rbon in soil.