Food Security and climate change

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Food Security & Climate Change the Biodiversity is the solution:

By Shimaa Eid Abdel-Ghany Under the supervision of Prof Dr, Hisham EL-Kassas Food Security & Climate Change the Biodiversity is the solution Shimaa Eid 1

Introduction :

Climate change will profoundly affect agriculture worldwide. Food security in many countries is under threat from unpredictable changes in rainfall and more frequent extreme weather. Farmers in poorer countries with harsh climate conditions will likely be most affected. Introduction Shimaa Eid 2

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A review of recent scientific literature underlines that the most effective strategy to adapt agriculture to climate change is to increase biodiversity. A mix of different crops and varieties in one field is a proven and highly reliable farming method to increase resilience to erratic weather changes. Shimaa Eid 3

Impact of climate change on agriculture and food security :

Some of the most profound and direct impacts of climate change over the next few decades will be on agriculture and food systems (Brown and Funk 2008). All quantitative assessments show that climate change will adversely affect food security (Schmidhuber and Tubiello 2007). Impact of climate change on agriculture and food security Shimaa Eid 4

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Increasing temperatures, declining and more unpredictable rainfall, more frequent extreme weather and higher severity of pest and disease are among the more drastic changes that would impact food production (Parry et al. 2007, Kotschi 2007, Morton 2007, Brown and Funk 2008, Lobell et al. 2008). Shimaa Eid 5

Biodiversity – a natural insurance policy against climate change :

Diversity farming is the single most important modern technology to achieve food security in a changing climate. Scientists have shown that diversity provides a natural insurance policy against major ecosystem changes, be it in the wild or in agriculture (McNaughton 1977, Chapin et al. 2000, Diaz et al. 2006). Biodiversity – a natural insurance policy against climate change Shimaa Eid 6

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It is now predicted that genetic diversity will be most crucial in highly variable environments and those under rapid human-induced climate change (Reusch et al. 2005, Hajjar et al. 2008, and Hughes et al. 2008). Shimaa Eid 7

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The larger the number of different species or varieties presents in one field or in an ecosystem, the greater the probability that at least some of them can cope with changing conditions. Species diversity also reduces the probability of pests and diseases by diluting the availability of their hosts (Chapin et al. 2000). Shimaa Eid 8

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This diversification strategy is backed by a wealth of recent scientific data Shimaa Eid 9

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In a unique cooperation project among Chinese scientists and farmers in Yunnan during 1998 and 1999, researchers calculated the effect of diversity on the severity of rice blast, the major disease of rice (Zhu et al. 2000). Shimaa Eid 10

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In Italy, a high level of genetic diversity within wheat fields on nonirrigated farms reduces risk of crop failure during dry conditions. A scenario where rainfall declines by 20 percent, the wheat yield would fall sharply, but when diversity is increased by 2 percent, this decline can not only be reversed but above average yields achieved (Di Falco and Chavas 2006, 2008). Shimaa Eid 11

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Agronomists in the United States compared corn yields between fields planted as monocultures and those with various levels of intercropping in Michigan over three years. Shimaa Eid 12

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There is abundant scientific evidence that crop biodiversity has an important role to play in the adaptation to our changing environment. Shimaa Eid 13

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Analysis of past environment changes that resulted in dramatic famines (e.g. Ireland’s potato famine and Ethiopia 1965-1997) shows specialised monocultures are highly vulnerable (Fraser, 2007). Shimaa Eid 14

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Modern breeding techniques for diverse genetic traits Shimaa Eid 15

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In addition to increasing the diversity of crops and varieties in a single field, increasing the diversity of traits within one variety might help climate change adaptation. If each of the single varieties in one field has a higher tolerance to droughts, salinity, floods, storms and pests, the overall resilience to extreme weather events will be higher. Shimaa Eid 16

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However, a review of the scientific literature reveals that the method of choice is not GE, but traditional and modern conventional breeding techniques, including Marker Assisted Selection (MAS). Shimaa Eid 17

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MAS facilitates the selection of conventional crosses with traits associated with multiple genes, including their as of yet unknown regulatory systems. By contrast, genetic engineering can only crudely insert a single or a few gene(s) without any control over regulatory mechanisms. Shimaa Eid 18

Some remarkable MAS successes:

Rice tolerant to unpredictable floods. Rice production can be subject to stresses such as seasonal flooding, which can be unpredictable and can damage young rice plants. Through genetic mapping researchers identified a DNA segment containing a gene that makes rice tolerant to prolonged submergence in water (Xu et al., 2006; Sasaki, 2006). Some remarkable MAS successes Shimaa Eid 19

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One expected effect of climate change is the spread of disease. A new strain of wheat stem rust (Ug99), a fungus that can devastate wheat crops, is spreading across Africa. Most cultivated wheat varieties are susceptible to this virulent strain and efforts are underway to develop resistant wheat using MAS. Shimaa Eid 20

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The limits of genetic engineering Shimaa Eid 21

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Extreme temperature fluctuations caused crop losses in Bt cotton in China. Researchers investigating the disaster said high temperatures (37 C) were most probably responsible for causing a drop in Bt concentrations in leaves (Chen et al, 2005) Shimaa Eid 22

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GE herbicide-resistant soybeans suffered unexpected losses in the US during very hot spring weather in 1998. Roundup Ready soybeans performed significantly worse than conventional varieties under conditions of heat stress. The GE soybean stems were more brittle and split more easily, thus allowing infection to enter (Coghlan, 1999). Shimaa Eid 23

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Herbicide tolerant GE soybeans currently on the market have been reported to have decreased yields of up to 10 percent compared to traditional varieties (Elmore et al, 2001). Massive herbicide use in conjunction with these GE plants has already led to an increase in tolerant weed populations (Nandula et al, 2005). Shimaa Eid 24

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Conclusions Shimaa Eid 25

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Bio-diverse farming is a proven, effective strategy to adapt to climate change. Through it we can create farms that are able to maintain and increase food production in the face of increasingly unpredictable conditions. Shimaa Eid 26

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Agriculture will not only be negatively affected by climate change, it is a substantial contributor to greenhouse gas emissions. By reducing agriculture’s greenhouse gas emissions and by using farming techniques that increase soil carbon, farming itself can contribute to mitigating climate change. Shimaa Eid 27

Selected References :

Altieri, M.A. 1990 . Agroecology. In: Agroecology (eds Carrol, C.R., Vandermeer, J.H. and Rosset, P.M.) 551–564. McGraw Hill, New York H.L., Hooper, D.U., Lavorel, S., Sala, O.E., Hobbie, S.E., Mack, M.C. and Diaz, S. 2000 . Consequences of changing biodiversity. Nature 405: 234-242. Chen, D., Ye, G., Yang, C., Chen, Y. and Wu, Y. 2005. The effect of high temperature on the insecticidal properties of Bt cotton. Environmental and Experimental Botany 53: 333–342. Morton, J.F. 2007 . Climate change and food security special feature: the impact of climate change on smallholder and subsistence agriculture. Proceedings of the National Academy of Sciences 104: 19680-19685. Smith, R.G., Gross, K.L., and Robertson, G.P. 2008 . Effects of crop diversity on agroecosystem function: crop yield response. Ecosystems 11: 355-366. Zhu, Y., Chen, H., Fan, J., Wang, Y., Li, Y., Chen, J., Fan, J., Yang, S., Hu, L., Leung, H., Mew, T. W., Teng, P.S., Wang, Z. and Mundt, C.C. 2000. Genetic diversity and disease control in rice. Nature 406: 718-722. Selected References Shimaa Eid 28

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