The human ecology of climate change - Climate Change: Biological and Human Aspects - page 419

Just as climate change sees monsoons deliver extreme maximum precipitation,
so there are minima too. In 2009 India suffered its weakest monsoon for 40 years.
Rainfall was at its lowest at the end of the monsoon season since 1972. There were
regional differences: the north west had the worst rainfall deficit, at 36%, while the
southern part of the country was just 7% below average. India is the world's second
biggest producer of rice ( Oryza spp.), wheat ( Triticum spp.) and sugar.
Whereas one incident cannot be specifically blamed on climate change, as noted
before, it is the pattern of events that is revealing and this instance is the sort of event
that one might expect with global warming. The greatest health impacts arising from
climate change are those that adversely impact on the increasing global population's
ability to feed itself. And then there are the biological secondary effects. For example,
in China, from analysis of records for the past 100 years, the years of most severe
locust outbreak were in the warm, dry years with warm, dry summers and warm, wet
winters. Locust outbreaks damage crops. Both interannual and decadal variability of
higher temperature changes have led to the highest locust outbreaks in the past 1000
years (Yu et al., 2009).
Water availability, be it a deficit or a surplus, is one factor that links climate change
to food security. This is the subject of the next section, in which we will discuss
drought in a little more detail.
7.4 Climatechangeandfoodsecurity
7.4.1 Pastfoodsecurity
Climate and food security have historically been central to a society and/or culture's
survival (see section 5.2.1). Humanity's food security improved greatly in the latter
quarter of the 20th century. This was due to the mechanisation of agriculture and
the use of chemical fertilizers and pesticides, which together formed the Green
Revolution that dramatically increased agricultural productivity (which is defined as
output per unit area). The success of the Green Revolution was evident by the late-
20th-century growth in global population (see the beginning of this chapter), which
in turn was built on previous population growth. As previously noted, the global
population (Figure 7.4a) began to increase following the Renaissance and continued
to rise with the Industrial Revolution. The rate of growth (as opposed to population
itself) peaked in the 20th century. This determined the size of the population in the
following decades (Figure 7.4b), which itself is expected to peak during this century
(Figure 7.5). All these extra mouths required, and will require, feeding.
Yet, there has been a price for this success. First, it did not come without its failures.
New agricultural practices were not always sustainable. Concerns such as soil erosion,
ecotoxicological impacts from chemical inputs and resistance to pesticides have meant
that techniques have had to be refined. Furthermore, the post-agricultural component
to food supply has come to dominate the economics of food supply so that, for
example, in the 1990s in the UK while agriculture contributed to a little over 1% of
its GDP, post-agricultural processing and commerce added more than another 2% (see