TRENDS IN NATIONAL FOOD SECURITY AND THE IMPACT OF CLIMATE - Food Security, Food Prices and Climate Variability - page 79

agro-ecological and organic intercropping approaches, is far more likely to be successful across
diverse economic, geopolitical and ecological contexts than a one-size-its all approach. Agri-
culture and food production need to be a priority, but investment needs to be done in ways
that conform with many other priorities of a food system, including providing culturally
appropriate food, employment, economic growth and providing for adequate human nutri-
tion (Garnett et al ., 2013; Tilman et al ., 2002).
Observed climate trends using precipitation and rainfall observations
To understand the impact of climate variability on food security, long-term rainfall datasets
have been examined for their trends, particularly in food insecure regions. Large changes in
moisture conditions can greatly exacerbate any short-term shocks to the food system, since
such trends disrupt food production and forces adaptation to these changes by communities
over short time frames. Rainfall station data are available in most countries, but must be ana-
lyzed in collaboration with local meteorological offices and often need to be digitized and
cleaned to ensure quality. By bringing together climate information with the amount of land
in cultivation, the trend in agricultural yields that have been observed in the country and the
population increase, an assessment of the impact of climate change on food security can be
determined. Table 4.2 summarizes the main conclusions from these climate assessments for
each country in which they have been conducted.
Climate impacts have recently become of particular importance to broader food security
analysis, since in some regions significant trends have been noted in rainfall and temperatures,
affecting agricultural productivity. Because these trends are occasionally compounded by
increases in population and reductions in agricultural investment and trade networks, trends in
climate need to be incorporated into strategies for appropriate response to food security crises.
Analysis of observed climate variability on global crop production
The impact of climate variability on production during the past two decades can be a guide
to how climate variability in the near future will likely impact yields and crop production in
the next two decades. Global average temperatures have risen by 0.13° Celsius since 1950
(IPCC, 2007a), and the impact this has had on agriculture has been explored by several
authors. These studies use yield response models to evaluate the impact of climate trends on
major crop yields at the country during the past two decades, and then use the relationships
derived to explore how future temperature change may affect future yields.
Lobell et al . (2011) presents results that show the total climate impacts depend on the crop
and can be disaggregated from negative temperature and precipitation effects and positive
CO 2 effects ( Table 4.3 ). Wheat and maize show the largest impact from temperature and
precipitation, supported by other studies in France (Brisson et al ., 2010) and India (Ladha et
al ., 2003). Wheat yields have been particularly affected by temperature and precipitation,
leveling off from nearly linear gains over the mid-twentieth century (Lin and Huybers, 2012).
Lin and Huybers show, for example, that half of the 47 regions that produce wheat has tran-
sitioned to level yields, no longer experiencing increases year over year. With the exception
of India, nearly all of these regions are in developed nations including the United Kingdom,
France and Germany. The effect of climate and a lack of investment in agricultural capacity
are identified as the primary causes of stagnating yields.