The recent UK Stern Review on the economic costs of climate change and Al Gore’s film An Inconvenient Truth have focused attention on the serious consequences that may result. A new review by Jurg Fuhrer published in CAB Reviews highlights the implications for agriculture, pointing out that it is “among the sectors most directly exposed to climate variability and change, with consequences for food production and food security”
Fuhrer, of the Air Pollution/Climate Group, Swiss Federal Research Station in Zurich, says that “effects on the overall agricultural potential may range from being extremely negative in already water-limited areas to more favourable in regions that are currently temperature-limited.”
His review concludes that a significant rise in temperature is likely to reduce crop yields in many areas. “In cooler regions, more favourable mean temperatures and the extension of the growing season could improve productivity. The most threatened systems are located in regions where temperature increases and rainfall declines.”
More frequent dry spells increase the risk for crop failure, says Fuhrer.“Crops with inherently low crop water productivity, or with large absolute water consumption, are likely the most sensitive. In contrast, systems with a larger water-holding capacity may be less sensitive.”
Rainfall is critical. “The balance between positive and negative effects on the productivity and composition of grasslands depends on the magnitude of precipitation changes. The sensitivity may be greater in extensively managed systems because of the lack of adaptive interventions.” Climate change will affect animal production too. This will happen through direct effects on animal wellbeing, and indirect effects through altered diet quality and forage availability.
What can be done? Fuhrer says "adaptive strategies are most effective at the level of farming systems and may include diversification, grain storage, irrigation, and protected cultivation. Ongoing adaptations will continue, depending on the sensitivity of the system of concern, and on the potential for adaptation of the respective socioeconomic environment."
The paper, "Agricultural systems: sensitivity to climate change", by J.Fuhrer, appears in CAB Reviews: Perspectives in Agriculture, Veterinary Science, Nutrition and Natural Resources, 2006, 1, No. 052, 8 pp.
Abstract:
Agriculture is among the sectors most directly exposed to climate variability and change, with consequences for food production and food security. This paper aims to review the most recent literature on the sensitivity to climate change of agricultural systems by considering four hierarchical levels: (i) crops and grasslands, (ii) cropping systems, (iii) livestock systems, and (iv) farming systems. The available information suggests that a significant rise in mean temperature is likely to reduce crop yields in many areas, with the most threatened systems located in areas with decreasing rainfall. In cooler regions, more favourable mean temperatures and the extension of the growing season may stimulate potential productivity. More frequent dry spells in a warmer climate are likely to increase the risk of crop failure, unless irrigation can be expanded and be combined with improved water retention and water yield. In grasslands, the sensitivity may be larger in extensively than in intensively managed systems because of the lack of adaptive management interventions. Finally, climate change could seriously alter the productivity of animal systems, both through direct effects on the animal well-being and indirect effects via diet quality and forage availability. Overall, there is ample evidence that agricultural systems are sensitive to climate change, and that effects on potential productivity ranges from being extremely negative in already water-limited areas to more favourable in currently temperature-limited regions.
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