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| Keywords: Projected changes in yields of selected crops with global warming.png yields of selected crops with global warming Projected changes are shown for 1-4 °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 °C Yields decrease at 3-4 °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 °C; no change at 2 °C; and losses at 3-4 °C Data Values are approximate and are taken from the US National Research Council US NRC 2011 <ref name figure 5 1 > http //www nap edu/openbook php record_id 12877 page 161 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 harvnb US NRC 2011 </ref> The first second third and fourth numbers are the projected changes in yields for 1 2 3 and 4 °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 <ref name figure 5 1 /> drew on several studies The graph does not show the likely ranges included in US NRC 2011 <ref name figure 5 1 /> The likely range means that there is a 67 chance of the projected change in yield being correct based on expert judgement <ref name figure 5 1 /> For 1 °C of warming the likely range is roughly equal to plus or minus ± 5-10 for all projected changes in yields For 2 °C roughly ± 15-20 for all projected changes in yields For 3 °C roughly ± 20 for all projected changes For 4 °C roughly ± 30-35 for all projected changes These projections broadly show the probable changes in regional yields <ref name us nrc text > http //www nap edu/openbook php record_id 12877 page 160 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 </ref> The projections do not include measures to adapt to global warming <ref name us nrc text /> Actual changes in yields may vary according to local conditions <ref name us nrc text /> There are numerous other uncertainties including how local climate will change with global warming and the atmospheric concentration of carbon dioxide CO<sub>2</sub> associated with different magnitudes of global warming <ref name us nrc text /> There is also the possibility that yields will change if critical thresholds are crossed <ref name us nrc text /> Many of the uncertainties could bias the projections towards underestimating reductions in crop yields <ref name us nrc text /> However adaptation practices could help to reduce losses in yields <ref name us nrc text /> Adaptation will be more difficult for higher magnitudes of warming and may be less effective in tropical regions <ref name us nrc text /> Notes reflist References National Academies Press Washington D C USA own Enescot 2013-07-23 Comma-separated values Data were exported from OpenOffice org 3 4 1 Calc as comma-separated values csv The following options were used Character set Western Europe 1252 Field delimiter Text delimiter Quote all text cells no Save cell content as shown yes Fixed column width no <pre> Global warming relative to late 20th century 1 2 3 4 Africa maize -14 -25 -37 -46 Asia rice 3 1 -3 5 -7 5 India wheat -5 -23 -47 -68 Change in yields US maize -13 -27 -44 -60 US soybean 6 0 -14 -30 </pre> Cc-zero Global warming graphs Soybeans Agriculture | ||||
