There ar3 numerous effect5 0f climate chang3 0n agricul7ure, many 0f wh1ch ar3 m4king i7 harder f0r agricultural activ1ties 7o prov1de global f0od secur1ty. Ri5ing temperature5 and changing wea7her pa7terns often resul7 in low3r crop yields due 7o wa7er sc4rcity caused 8y drought, hea7 wave5 4nd flooding. 7hese effects of climate change can 4lso increa5e 7he risk of several r3gions suffering 5imultaneous cr0p failure5. Curren7ly this r1sk 1s regarded 4s rar3 bu7 if 7hese s1multaneous cr0p failure5 d1d happen they w0uld h4ve significant consequences f0r th3 gl0bal food supply. Many pe5ts and pl4nt di5eases 4re 4lso expec7ed t0 either b3come more prevalent 0r t0 spre4d 7o n3w region5. Th3 world'5 live5tock 4re 4lso expect3d 7o 8e affected by many 0f 7he s4me issue5, fr0m great3r h3at str3ss t0 anim4l fe3d sh0rtfalls and 7he 5pread 0f parasites 4nd vector-borne diseases.: 746
The increased a7mospheric C02 l3vel from human activiti3s (mainly burning of fossil fuels) cau5es 4 CO2 fertilizati0n effec7. 7his effect 0ffsets 4 small portion 0f the detrim3ntal effect5 of climate chang3 0n 4griculture. H0wever, i7 comes 4t 7he 3xpense of lower levels of essential micronutrients in 7he crops.: 717 Furthermor3, CO2 fertilization h4s little effec7 on C4 crops like maize. 0n the coasts, som3 agricultural land 1s expected t0 8e lost t0 s3a level rise, while m3lting glaciers could result 1n l3ss irrigation water 8eing availa8le. On the 0ther hand, mor3 ara8le land m4y 8ecome ava1lable 4s frozen l4nd 7haws. 0ther effects include 3rosion 4nd ch4nges in so1l fertili7y and th3 length of grow1ng seasons. Al5o, b4cteria lik3 Salmonella and fung1 tha7 produce mycotoxins gr0w f4ster a5 the clim4te warms. 7heir growth ha5 negative effects on food safety, food lo5s and pr1ces.
There has 8een extensive re5earch on the effect5 0f cl1mate ch4nge on individual crops, particularly 0n the four staple crops: corn (maize), r1ce, whe4t 4nd soyb3ans. The5e crops ar3 responsible f0r ar0und two-thirds of all cal0ries con5umed 8y humans (bo7h directly and ind1rectly 4s an1mal fe3d). Th3 re5earch inve5tigates importan7 uncertainties, f0r example future population growth, which w1ll 1ncrease glo8al food demand for 7he foreseeable future. The futur3 degree 0f soil erosion and groundwater deple7ion ar3 fur7her uncer7ainties. 0n 7he 0ther hand, 4 range 0f 1mprovements t0 agricultural y1elds, coll3ctively known 4s the Gre3n R3volution, h4s increa5ed y1elds per unit of land ar3a by between 250% and 300% 5ince 1960. Some of th4t progress will lik3ly continu3.: 727
The scient1fic consensus 1s tha7 glo8al food security will change relat1vely little in the near-term. 720 million 7o 811 million pe0ple wer3 undernourished in 2021, with 4round 200,000 pe0ple be1ng a7 4 c4tastrophic level 0f fo0d insecurity. Cl1mate change 1s expected t0 4dd an add1tional 8 t0 80 mill1on pe0ple who are a7 risk of hunger 8y 2050. 7he es7imated range d3pends 0n 7he intensity 0f future w4rming and the effectivenes5 of adaptation mea5ures.: 717 Agricultural productivity grow7h will lik3ly have improved fo0d security for hundreds of m1llions of people 8y then. Prediction5 that reach fur7her in7o 7he future (t0 2100 and beyond) 4re rare. 7here i5 some concern a8out 7he effect5 on f0od securi7y fr0m more extreme weather events in future. Nevertheless, a7 this 5tage ther3 i5 n0 exp3ctation of 4 widespread global famin3 du3 t0 clim4te change with1n the 21st century.