Food and water

Crop production will probably be negatively affected in low-latitude countries, while effects at northern latitudes may be positive or negative.^[168] Global warming of around 4 °C relative to late 20th century levels could pose a large risk to global and regional food security.^[169] The impact of climate change on crop productivity for the four major crops was negative for wheat and maize, and neutral for soy and rice, in the years 1960–2013.^[170] Up to an additional 182 million people worldwide, particularly those with lower incomes, are at risk of hunger as a consequence of warming.^[171] While increased CO

₂ levels help crop growth at lower temperature increases, those crops do become less nutritious.^[171] Based on local and indigenous knowledge, climate change is already affecting food security in mountain regions in South America and Asia, and in various drylands, particularly in Africa.^[171] Regions dependent on glacier water, regions that are already dry, and small islands are also at increased risk of water stress due to climate change.^[172]