A brief review on the consequences of climate change for agricultural output.
Climate change is believed to be one of the global problems. For some time past the extreme weather events have become more intense and frequent all over the world. Europe experiences more lenghty heat waves, more severe river flooding in northern parts and river flow droughts in southern regions. Sea level rise in the next several decades may dramatically affect large densely populated agglomerations (such as Amsterdam, London, Rotterdam). But how climate change will influence European and Central Asian agricultural areas? Are there any threats to regional food security? Let us see what researchers say about it.
In 2014 NASA specialists Rosenzweig et al. conducted the intercomparison analysis of multiple global gridded crop models to identify the response of crops to climate change, and to better understand risks and opportunities in regard to food production and food security. On the picture below one can see the impact of climate change on crop productivity. Yellow to red areas correspond with yield changes up to -50%. Blue areas reflect yield increase by up to +50% according to authors’ model projections. It is apparent that European and Central Asian region is expected to benefit from the climate change (the only exception is maize, which yields may fall in Southern regions of Europe).
Another line of research models forecasts an increase in the growing season for European countries (Trnka et al., 2011). Eastern Europe and Central Asia are expected to see large gains in the frost-free period suitable for crop growth (Ramankutty et al., 2002). At the same time, one should take into account the other end of the spectrum. For example, warming increases the likelihood of heat stress during the critical reproductive period, which can lead to sterility, lower yields, and the risk of complete crop failure (Teixeira et al., 2012). Higher temperature and atmospheric CO2 may favor the growth and survival of many pests and diseases specific to agricultural crops (Ziska et al., 2011).
Lobell et al. (2011) conducted a global-scale study, which estimated the climate change impacts for a 29-year period. Warming trends were estimated to have lowered wheat and maize yields by 6% and 4%, respectively. Their model suggests that soybean and rice yields will be relatively unaffected by changes. However, they discover that climate change and higher CO2 will increase crops yield in a number of geographic areas. They argue that in the near term the warming will slow down the global yield growth by about 1.5% per decade while CO2 increases will raise yields by approximately the same amount. This balance is broadly consistent with the global picture emerging from many studies and major assessments. Such a balance is expected to hold at least until 2050s. After that CO2 benefits may taper off and climate effects may be larger. The researchers argue that even in the most pessimistic scenarios, it is highly unlikely that climate change would result in a net decline in global yields (Lobell and Gourdji, 2012). At the same time until 2050 technological and agronomic improvements will continue to be main drivers of the growth rates in aggregate crop productivity, as it was before.
Thus the climate change is expected to benefit agricultural output of Europe and Central Asia, which will balance the global net yields. However, Nelson et al. (2014) argue that with a negative productivity effect from climate change, prices will increase and trigger more intensive management practices and area expansion.