UN Food and Agriculture Organization study from 2015, under a high-emission climate scenario, harvest reductions by 2100 of between -20 and -45 percent are expected for maize (corn), between -5 and -50 percent for wheat, between -20 and -30 percent for rice, and between -30 and -60 percent for soybeans. The study ignores offset by the beneficial effects of CO2 fertilization since plants grow more vigorously in high-CO2 conditions.
Greenhouses have been built and produce crops in the hottest deserts now. They have climate and humidity control. They use 7% of the water to grow crops compared to open-air farming.
Climate Change is something to be minimized. However, climate change only impact open-air farming. All food production can be brought indoors where it will be virtually immune to climate change.
China is planning to have over 2 million hectares of greenhouse buildings by 2025 with mechanized-automation of farming. The Ministry of Agriculture and Rural Affairs Monday issued a guideline to promote the country's facility-based agricultural planting, outlining goals for infrastructure upgrades and mechanization to boost output and farmers' income. By 2025, China will maintain over 2 million hectares of facilities, including plastic greenhouses, and achieve above 50 percent mechanization for facility-based planting, a sector of the so-called controlled-environment agriculture (CEA), or protected agriculture.
The world already has about 500,000 hectares of climate-controlled greenhouses. China has 4 million hectares of crude plastic sheeting covering land in partially enclosed conditions. The plastic sheets lie over simple metal poles and crude framing.
IF there was a need, the entire world could bring all agriculture indoors and under temperature and humidity control by 2035.