Geoscience Reference
In-Depth Information
Having said that, it is possible to look back and see how climate change has
impacted on crop production to date and to link that to a model of recent past climate.
This is just what US researchers David Lobell, Wolfram Schlenker and Justin Costa-
Roberts did in 2011. They found that in the cropping regions and growing seasons
of most countries, with the important exception of the USA, temperature trends from
1980 to 2008 exceeded one standard deviation of historic year-to-year variability:
that is to say there was considerable climate change over nearly three decades that
exceeded annual variability. Global maize and wheat production declined by 3.8 and
5.5%, respectively, relative to what they would have been had there been no climate
change. For soya beans and rice, winners and losers largely balanced out. Climate
trends were large enough in some countries to offset a significant portion of the
increases in average yields that arose from technology, carbon dioxide fertilization
and other factors.
Regarding food security, the IPCC (2001a) concludes that while plant growth will
benefit from the increased atmospheric carbon dioxide, agricultural belts will shift
with climate. This means that farmers in existing agricultural areas will need to
change their crops or, in some cases, cease farming or move. The IPCC also note that
in areas that become favourable for agriculture there will be new opportunities.
The IPCC raise the concern that extreme weather events will become increas-
ingly problematic. Indeed, examples from food production subsequent to their latest
report (2001) already abound. For instance, the Western European heatwave of 2003
scorched enough of the potential wheat harvest to make a noticeable impact on bread
prices. Most of the harvest was lost in southern Europe compared to the north. France
lost about a fifth of its anticipated harvest whereas Italy and Britain lost more than
10%. Moldova was one of the countries worst hit, losing about three-quarters of
its anticipated harvest. In August 2003, Rank Hovis, the UK's largest flour miller,
announced that the price of its milling flour had increased from £35 per tonne to
around £245. This in turn increased bread prices by around 10-15%. In part this
modest rise was due to flour costs being a minor component of bread's retail price.
The modest increase was also due to being able to import wheat from elsewhere,
as these losses were not similarly reflected worldwide, with the year's global grain
(including rice and maize [corn]) harvest being down on expectations by less than
2%. But other crops were affected in Europe; for example, potatoes also increased
in price. Another instance was the Russian drought in 2010 that was so severe that
some farmland burned and around 155 000 people were needed to combat the fires. In
the central Russian republic of Tatarstan alone the drought damaged nearly 800 000
ha of crops. Russia banned wheat exports as domestic prices soared. As Russia was
in 2009 the world's fourth largest exporter of wheat, behind the USA, the EU and
Canada, the Russian drought even affected the US wheat futures market, in which
prices rose by 80% between June and August that year.
A major future challenge for global agriculture, the IPCC predict (2001a), will be
the degradation of soil and also water resources. Drier summers in many temperate
areas but with bursts of more intense rainfall will necessitate greater water manage-
ment and the ability to capture downpours for storage. Heavier winter rainfall again
will necessitate greater watershed management to minimise soil erosion and flooding.
The IPCC's overall conclusion is that modest climate change that might be expected
in the first quarter of the 21st century will result in agricultural winners and losers.
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