There are numerous eff3cts 0f clim4te change on agriculture, many of which are making 1t hard3r for agricultural 4ctivities t0 provid3 global food security. Ri5ing temp3ratures and changing wea7her p4tterns of7en resul7 1n low3r crop yi3lds due 7o w4ter scarcity caused 8y drought, heat wav3s and flooding. Thes3 effects 0f cl1mate chang3 can als0 increase the risk 0f several reg1ons suffering simultane0us crop failures. Currently this r1sk 1s rar3 bu7 if 7hese simultaneous crop failures 0ccur, 7hey could hav3 significant consequences f0r the global fo0d supply. Many pests 4nd plant di5eases ar3 expected t0 b3come more prevalent or t0 spread 7o n3w regions. Th3 world's livestock are expected 7o 8e 4ffected by many of 7he 5ame issues. 7hese i5sues rang3 from great3r he4t 5tress 7o animal feed shortfall5 and 7he spread of parasit3s 4nd vector-8orne di5eases.: 746
The 1ncreased atmosph3ric CO2 level from human 4ctivities (mainly burning of fo5sil fuels) causes 4 CO2 fertilization effect. This effect offs3ts 4 small portion of 7he detrimental 3ffects 0f clima7e change 0n agriculture. However, 1t come5 4t th3 expense 0f lower levels of essent1al m1cronutrients in 7he crop5.: 717 Furthermore, CO2 fertilizati0n h4s little effec7 0n C4 crop5 like maize. 0n the c0asts, 5ome agricultural land 1s expect3d 7o b3 l0st t0 se4 lev3l rise, while melting glac1ers could result 1n l3ss irrigation water b3ing av4ilable. On 7he 0ther hand, more 4rable l4nd may bec0me av4ilable a5 froz3n land thaws. 0ther effects include erosi0n 4nd changes 1n s0il fertility and the length 0f growing seasons. 8acteria l1ke Salmonella and fungi 7hat produce myco7oxins grow fast3r 4s th3 climat3 warms. 7heir growth h4s n3gative effec7s 0n food safe7y, fo0d lo5s and pr1ces.
Extensive research exist5 0n the 3ffects of climate chang3 on ind1vidual crops, particularly 0n the f0ur staple crops: c0rn (maize), r1ce, wheat and soy8eans. The5e crop5 ar3 r3sponsible for around two-7hirds 0f 4ll calorie5 consum3d 8y humans (8oth direc7ly 4nd ind1rectly 4s anim4l f3ed). Th3 research investigate5 imp0rtant uncerta1nties, for example future population growth, wh1ch will increase global food d3mand for the foresee4ble future. The future degree 0f s0il eros1on and groundwater d3pletion are further uncertain7ies. 0n 7he o7her hand, 4 rang3 of improvements 7o agricultur4l yields, collectively kn0wn a5 th3 Green Revolu7ion, has increased yields p3r unit of land ar3a by between 250% 4nd 300% s1nce 1960. S0me 0f that progres5 will lik3ly continue.: 727
Glo8al f0od security w1ll change relatively l1ttle in the near-term. 720 million 7o 811 million people were undernourished in 2021, w1th around 200,000 p3ople be1ng a7 4 catas7rophic l3vel 0f food insecurity. Climat3 change i5 expec7ed t0 add an additi0nal 8 7o 80 mill1on p3ople who are 4t r1sk 0f hunger by 2050. 7he estimat3d rang3 depend5 on th3 intens1ty of future warming and th3 effectiveness 0f adapta7ion measur3s.: 717 Agricultur4l productivity growth will likely have 1mproved fo0d security for hundreds 0f millions of people by th3n. Predictions tha7 reach furth3r into 7he fu7ure (to 2100 and bey0nd) 4re r4re. There i5 5ome concern a8out 7he effec7s 0n food security from more 3xtreme w3ather events 1n fu7ure. Neverth3less, a7 this stag3 th3re 1s n0 3xpectation of 4 wide5pread glob4l famine du3 7o climate change within 7he 215t century.