Impacts of climate changes on crop physiology and food quality Fábio M. DaMatta a, * , Adriana Grandis b , Bruna C. Arenque b , Marcos S. Buckeridge b a Departamento de Biologia Vegetal, Universidade Federal de Viçosa, 36570-000 Viçosa, MG, Brazil b Laboratório de Fisiologia Ecológica de Plantas (LAFIECO), Departamento de Botânica, Instituto de Biociências, Universidade de São Paulo, Caixa Postal 11461, 05422-970 São Paulo, SP, Brazil article info Article history: Received 8 June 2009 Accepted 5 November 2009 Keywords: Food quality Global climatic changes Global warming Plant physiology Photosynthesis Nitrogen abstract Carbon emissions related to human activities have been significantly contributing to the elevation of atmospheric [CO 2 ] and temperature. More recently, carbon emissions have greatly accelerated, thus much stronger effects on crops are expected. Here, we revise literature data concerning the physiological effects of CO 2 enrichment and temperature rise on crop species. We discuss the main advantages and lim- itations of the most used CO 2 -enrichment technologies, the Open-Top Chambers (OTCs) and the Free-Air Carbon Enrichment (FACE). Within the conditions expected for the next few years, the physiological responses of crops suggest that they will grow faster, with slight changes in development, such as flow- ering and fruiting, depending on the species. There is growing evidence suggesting that C 3 crops are likely to produce more harvestable products and that both C 3 and C 4 crops are likely to use less water with ris- ing atmospheric [CO 2 ] in the absence of stressful conditions. However, the beneficial direct impact of ele- vated [CO 2 ] on crop yield can be offset by other effects of climate change, such as elevated temperatures and altered patterns of precipitation. Changes in food quality in a warmer, high-CO 2 world are to be expected, e.g., decreased protein and mineral nutrient concentrations, as well as altered lipid composi- tion. We point out that studies related to changes in crop yield and food quality as a consequence of glo- bal climatic changes should be priority areas for further studies, particularly because they will be increasingly associated with food security. Ó 2009 Elsevier Ltd. All rights reserved. 1. Introduction Over the past 800,000 years, atmospheric [CO 2 ] changed be- tween 180 ppm (glacial periods) and 280 ppm (interglacial peri- ods) as Earth moved between ice ages. From pre-industrial levels of 280 ppm, [CO 2 ] has increased steadily to 384 ppm in 2009, and mean temperature has increased by 0.76 °C over the same time period. Projections to the end of this century suggest that atmo- spheric [CO 2 ] will top 700 ppm or more, whereas global tempera- ture will increase by 1.8–4.0 °C, depending on the greenhouse emission scenario (IPCC, 2007). There is growing evidence suggest- ing that many crops, notably C 3 crops, may respond positively to increased atmospheric [CO 2 ] in the absence of other stressful con- ditions (Long, Ainsworth, Rogers, & Ort, 2004), but the beneficial direct impact of elevated [CO 2 ] can be offset by other effects of cli- mate change, such as elevated temperatures, higher tropospheric ozone concentrations and altered patterns of precipitation (Easter- ling et al., 2007). The temperature response of crop growth and yield must be considered to predict the [CO 2 ] effects (Morison & Lawlor, 1999; Polley, 2002; Porter & Semenov, 2005; Ziska & Bunce, 1997). The threshold developmental responses of crops to temperature are of- ten well defined, changing direction over a narrow temperature (Porter & Semenov, 2005). High temperatures reduce the net car- bon gain in C 3 species by increasing photorespiration; by reducing photorespiration, [CO 2 ] enrichment is expected to increase photo- synthesis more at high than at low temperatures, and thus at least partially offsetting the temperature effects of supra-optimal tem- peratures on yield (Long, 1991; Polley, 2002). Therefore, yield in- creases at high [CO 2 ] should occur most frequently in regions where temperatures approximate the optimum for crop growth. Conversely, in regions where high temperatures already are se- verely limiting, further increases in temperature will depress crop yield regardless of changes in [CO 2 ](Polley, 2002). In fact, results of mathematical modeling suggest that, in mid- to high-latitude re- gions, moderate to medium local increases in temperature (1– 3 °C), along with associated CO 2 increase and rainfall changes, can have beneficial impacts on crop yields, but in low-latitude regions even moderate temperature increases (1–2 °C) are likely to have negative impacts on yield of major cereals (Easterling et al., 2007). Thus, climate change may impair food production, 0963-9969/$ - see front matter Ó 2009 Elsevier Ltd. All rights reserved. doi:10.1016/j.foodres.2009.11.001 * Corresponding author. Fax: +55 31 3899 2580. E-mail addresses: fdamatta@ufv.br (F.M. DaMatta), msbuck@usp.br (M.S. Buck- eridge). Food Research International 43 (2010) 1814–1823 Contents lists available at ScienceDirect Food Research International journal homepage: www.elsevier.com/locate/foodres