Few industries are more dependent on ideal climatic conditions than agriculture - and few if any are as central to the underpinnings of civilization. In general terms, it is difficult to provide a blanket prediction of the impacts of climate change on agriculture: after all, increased temperatures and CO2 may prompt growth of some plant species, but in doing so may negatively impact their yields, by reducing the amount of time that seeds have to grow and mature.
And those temperature and CO2 increases may benefit weeds more than grains such as wheat or rice. In general, though, increasing temperatures and extreme weather events are likely to affect the range and viability of much agriculture.
Three grains - wheat, corn, and rice - support the bulk of the world's food intake, and the United States provides 30 percent of the global supply, so what happens here matters a great deal. According to a recent US government report, in the short term the industry is expected to prove quite resilient, but by the middle of the century, "the rising incidence of weather extremes will have increasingly negative impacts on crop and livestock productivity."
Some areas, such as California's central valley, will be especially hard hit, with not just wheat, corn and rice, but also sunflowers, tomato, and cotton expected to lose 10-30 percent of their yields.
Throughout the country, fruit and nut crops that depend on "winter chilling" days may have to relocate, as will crops that are already 'on the fringes,' such as maple. Animals exposed to many hot nights will become increasingly stressed. Many vegetable crops will be hit when temperatures rise only a few degrees above normal. With both crops and animals already stressed, the industry will be at yet greater vulnerability from extreme events such as drought, fires, and rainfall. Long story short: in the short term, don't expect too many disruptions, but expect increases in food prices, and periodic shortages of some crops, in the future.