page_title: Effects of global warming
section_title: Food availability
hierarchical_section_title: Effects of global warming / On humans / Food security / Food availability
caption_attribution_description: English: This bar graph shows projected changes in yields of selected crops with global warming. Projected changes are shown for 1-4&#160;°C of global warming, relative to late 20th century. Changes in yield are shown for African maize, Asian rice, Indian wheat, US maize, and US soybean. Summary of changes: African maize: Declining yields at all temperatures, with reductions increasing with temperature. Asian rice: Small increases in yield for 1-2&#160;°C. Yields decrease at 3-4&#160;°C Indian wheat: Losses at all temperatures, with losses increasing with temperature. US maize: Losses at all temperatures, with losses increasing with temperature. US soybean: Gains at 1&#160;°C; no change at 2&#160;°C; and losses at 3-4&#160;°C. Data Values are approximate and are taken from the US National Research Council (US NRC, 2011).&#91;1&#93; The first, second, third and fourth numbers are the projected changes in yields (%) for 1, 2, 3 and 4&#160;°C of global warming, respectively.: Africa maize: -14, -25, -37, -46 Asia rice: +3, +1, -3.5, -7.5 India wheat: -5, -23, -47, -68 US maize: -13, -27, -44, -60 US soybean: +6, 0, -14, -30 These data are also available as comma-separated values. US NRC (2011)&#91;1&#93; drew on several studies. The graph does not show the "likely" ranges included in US NRC (2011).&#91;1&#93; The likely range means that there is a 67% chance of the projected change in yield being correct, based on expert judgement.&#91;1&#93; For 1&#160;°C of warming, the likely range is roughly equal to plus or minus (&#177;) 5-10% for all projected changes in yields. For 2&#160;°C: roughly &#177; 15-20% for all projected changes in yields. For 3&#160;°C: roughly &#177; 20% for all projected changes " ". For 4&#160;°C: roughly &#177; 30-35% for all projected changes " ". These projections broadly show the probable changes in regional yields.&#91;2&#93; The projections do not include measures to adapt to global warming.&#91;2&#93; Actual changes in yields may vary according to local conditions.&#91;2&#93; There are numerous other uncertainties, including how local climate will change with global warming, and the atmospheric concentration of carbon dioxide (CO2) associated with different magnitudes of global warming.&#91;2&#93; There is also the possibility that yields will change if critical thresholds are crossed.&#91;2&#93; Many of the uncertainties could bias the projections towards underestimating reductions in crop yields.&#91;2&#93; However, adaptation practices could help to reduce losses in yields.&#91;2&#93; Adaptation will be more difficult for higher magnitudes of warming, and may be less effective in tropical regions.&#91;2&#93; Notes ↑ a b c d Figure 5.1, p.161, in: Sec 5.1 FOOD PRODUCTION, PRICES, AND HUNGER, in: Ch 5: Impacts in the Next Few Decades and Coming Centuries, in US NRC 2011 ↑ a b c d e f g h pp.160-162, Sec 5.1 FOOD PRODUCTION, PRICES, AND HUNGER, in: Ch 5: Impacts in the Next Few Decades and Coming Centuries, in US NRC 2011 References US NRC&#32;(2011)&#32;Climate Stabilization Targets: Emissions, Concentrations, and Impacts over Decades to Millennia[1], Washington, D.C., USA&#58; National Academies Press
context_page_description: The effects of global warming or climate damage include far-reaching and long-lasting changes to the natural environment, to ecosystems and human societies caused directly or indirectly by human emissions of greenhouse gases. It also includes the economic and social changes which stem from living in a warmer world. Human caused climate change is one of the threats to sustainability.
  Many physical impacts of global warming are already visible, including extreme weather events, glacier retreat, changes in the timing of seasonal events, sea level rise, and declines in Arctic sea ice extent. The future impact of global warming depends on the extent to which nations implement prevention efforts and reduce greenhouse gas emissions. Ocean acidification is not a consequence of global warming, but instead has the same cause: increasing atmospheric carbon dioxide.
  Climate change has already impacted ecosystems and humans as well. In combination with climate variability, it makes food insecurity worse in many places and puts pressure on fresh water supply. This in combination with extreme weather events, leads to negative effects on human health.
context_section_description: As of 2019, negative impacts have been observed for some crops in low-latitudes (maize and wheat), while positive impacts of climate change have been observed in some crops in high-latitudes (maize, wheat, and sugar beets).
  Using different methods to project future crop yields, a consistent picture emerges of global decreases in yield. Maize and soybean decrease with any warming, whereas rice and wheat production might peak at 3 °C of warming.
  In many areas, fisheries have already seen their catch decrease because of global warming and changes in biochemical cycles. In combination with overfishing, warming waters decrease the maximum catch potential. Global catch potential is projected to reduce further in 2050 by less than 4% if emissions are reduced strongly, and by about 8% for very high future emissions, with growth in the Arctic Ocean.
caption: 2011 projected changes in yields of selected crops with global warming. This graph is based on several studies.[139]
exif: {}