Page 24 - FAO-IPCC Expert meeting on climate change

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1.1 Projected productivity changes and extreme events
1.1.1 Crops
In terms of global temperature and the yield response curves for crops such as wheat and maize, the main change in AR5 compared with the Fourth Assessment Report (AR4) is that a 1 or 2 oC warming to increase yields in temperate regions is no longer expected, although there is less certainty about when any change will occur. Adding current adaptation practices to these scenarios will improve yields by seven to eight percentage points, the change is not sufficient to reverse the negative climate impacts in hotspot areas. Regional assessments of the impacts on crop yields for major crops, such as maize and wheat, show that the magnitude of loss is higher in lower yielding regions (i.e. in proportion to yield). Overall aggregate impacts are fairly robust, considering the known model uncertainties. Moreover, there are no significant changes from recent data runs compared to AR4 or AR5. It is also known that crop production effects depend on land use which, in turn, is affected by climate, weather and policies, all of which should be better integrated into current models.
It is also essential to focus on the modelling of extreme events, and more studies are attempting to quantify and measure yield variability under such events. A great deal, however, remains to be done. The task at hand is very complex and requires innovative approaches to account for production anomalies and price shocks. Traditional models for measuring variability may not be adequate as the risks are difficult to characterize and quantify, in particular events that are less likely but can have enormous impact. One option is to first approach extreme events from the effects (e.g. food price hikes) and establish the paths back to climate variability. More complex approaches require seeking evidence of the links between environmental tipping points and the food system dynamics and examining how these events interact with a view to drawing plausible outcome scenarios and potential responses.
In terms of food security1, it is critical to understand climate-induced food price shocks and their transmission across sectors and borders better. This may require combining climate assessments Myers et al. (2014) with the vulnerability of the food system; that is, a geographic approach (i.e. at the regional or local level), better mapping of the policy and institutional environment (including private actors) and a combination of quantitative and qualitative approaches to scenario assessments.
A nutrition perspective on climate impacts on food production has been limited but is central to assess fully the role of climate change on food security. Impact results are mostly reported in terms of weight loss but there is recent evidence of a decrease in the quality, i.e. protein and nutrient content, of crops grown under elevated CO2.2 Furthermore, these effects on forage quality are expected to impact on livestock and thus further alter food security. Climate change impacts and nutrition should also be explicitly addressed in the fisheries and aquaculture sector.
1.1.2 Livestock
Livestock is the most significant land user of land-based food systems and its contribution to the livelihood and food security of millions of people cannot be understated. There is also a large heterogeneity in livestock production, ranging from mixed crop livestock, pasture-raised livestock and rangeland systems to industrial livestock production. Climate change impact on livestock can be direct (e.g. heat stress, disease) or indirect (e.g. water, feed, biodiversity and loss
of habitat). Climate change can also reduce genetic diversity and limit adaptive capacity. IPCC’s AR5 acknowledges the paucity of quantitative evidence linking climate change to livestock and feed systems. There is relatively more local information but few global or regional assessments, although initial qualitative analyses are available. Furthermore, global warming is expected to alter the nutritional composition of food, including the protein value of livestock products as a result of changes in forage quality and the effects of heat stress on animals.
World Food Summit of 1996 codified the definition of food security as “a state when all people, at all times, have physical and economic access to sufficient, safe and nutritious food that meets their dietary needs and food preferences for an active and healthy life” (World Food Summit, 1996). FAO defines food security by differentiating four dimensions: availability of food, accessibility (economically and physically), utilization (the way it is used and assimilated by the human body) and stability of these three dimensions.
Myers et al. (2014)
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FAO-IPCC Expert meeting on climate change, land use and food security