Prediction of seasonal climate-induced variations in global food production

Abstract

USAConsumers, including the poor in many countries, are increasingly dependent on food imports 1 and are therefore exposed to variations in yields, production, and export prices in the major food-producing regions of the world. National governments and commercial entities are therefore paying increased attention to the cropping forecasts of major food-exporting countries as well as to their own domestic food production. Given the increased volatility of food markets and the rising incidence of climatic extremes affecting food production, food price spikes may increase in prevalence in future years 2-4 . Here we present a global assessment of the reliability of crop failure hindcasts for major crops at two lead times derived by linking ensemble seasonal climatic forecasts with statistical crop models. We found that moderate-to-marked yield loss over a substantial percentage (26-33%) of the harvested area of these crops is reliably predictable if climatic forecasts are near perfect. However, only rice and wheat production are reliably predictable at three months before the harvest using within-season hindcasts. The reliabilities of estimates varied substantially by crop-rice and wheat yields were the most predictable, followed by soybean and maize. The reasons for variation in the reliability of the estimates included the differences in crop sensitivity to the climate and the technology used by the crop-producing regions. Our findings reveal that the use of seasonal climatic forecasts to predict crop failures will be useful for monitoring global food production and will encourage the adaptation of food systems to climatic extremes.Although global crop monitoring and yield prediction models (e.g., the Global Information and Early Warning System of the FAO 5 and the Famine Early Warning Systems Network 6 ) have been developed, few studies have evaluated the reliability of seasonal climatic forecast-based cropping predictions on a global scale to date. However, global commodity markets are essential to maintaining national food balances and affordable access for consumers, including the poor 7, 8 . Large increases in food prices since 2008, occurring as a result of the widespread drought in crop-export regions in 2008 and 2012, coupled with a transforming food system (i.e., the increasing production of biofuels) increase the importance of being able to anticipate large changes in food production 9-11 . These changes affect both the rural and urban poor who are reliant on imports from the global commodity market to ensure that a sufficient amount of food is available to meet demand.We conducted a global overview of the reliability of crop failure forecasts for maize, rice, wheat, and soybean, which are the principal cereal and legume crops worldwide, providing nearly 60% of all calories produced on croplands 12 . The key question posed was "How reliable is the forecasting of crop failure at lead times that allow such information to be of value to governments and commercial concerns?" Previous work on this topic focus...

Impacts of El Niño Southern Oscillation on the global yields of major crops

“…We only used the top 10% samples to avoid cells in which the irrigated and rainfed areas are mixed. These setups are the same with those used in the previous study 2 . We collected the differences in averaged yield anomaly between El Niño (La Niña) years and neutral years over the corresponding cells for each of the two calculation methods of normal yield (the 5-year running mean method and local polynomial regression method).…”

“…The months of the reproductive growth period were specified in each grid cell using the global crop calendar 31 . Although the climatic conditions during the vegetative growth period are also important, those during the reproductive growth period are factors that more directly determine yields, and thus have been widely used in previous work in the derivation of a climate-crop relationship 2,32 .…”

“…T he monitoring and prediction of climate-induced variations in crop yields, production and export prices in major food-producing regions have become increasingly important to enable national governments in import-dependent countries to ensure supplies of affordable food for consumers, including the poor 1,2 . Given the high reliability of seasonal El Niño/Southern Oscillation (ENSO) forecasts 3,4 , linking variations in global yields with ENSO phase has a potential benefit to food monitoring 5 and famine early warning systems 6 .…”

Rising temperatures reduce global wheat production

“…3a). The increase in year-to-year yield variability is critical economically as it could decrease some regional-and hence global-stability in wheat grain supply 18 , amplifying market and price fluctuations 19 .…”

Urbanisation, Nutrition and Food Security: A Climatological Perspective

“…There is also ongoing work on weather and food security, especially the role of seasonal forecasting in improving agricultural yields (IIzumi et al 2013 ) which has more recently shown that improved forecasts can be achieved worldwide if the state of ENSO, the El Nino Southern Oscillation, is incorporated into yield forecasts. However, work by Asseng et al ( 2013 ) indicates that a greater proportion of the uncertainty in climate change impact projections of crop yields is due to variations among crop models rather than to variations among the downscaled climate models.…”