Climate models predict hard times ahead for global food production
- 21 Aug 2013, 12:50
- Freya Roberts
Global food production is set to take a hit in the
coming decades, new research predicts.
As rising greenhouse gas emissions drive changes in
rainfall patterns, river flows and temperatures, the availability
of food may decline, it says.
What's more, with less to go around, food prices look
set to rise while welfare standards fall.
Less food, more expensive
research, published in the journal Climatic
Change, shows that under both optimistic and pessimistic scenarios
of future emissions, the many effects of climate change could
together cause food production to fall 0.5 per cent by the end of
this decade, and 2.3 per cent by the 2050s.
As a result of the decrease in food production, the
price of food is set to rise, the paper says. By midcentury, staple
foods like cereal grains, sugar cane and wheat are predicted to be
roughly 40 per cent more expensive than they would be in a world
without climate change.
Fruit and vegetable prices are similarly effected,
costing 30 per cent more in a climate changed world in
Winners and losers
The research suggests that welfare standards and
economic growth could suffer as a direct result of shrinking food
resources and rising prices. Worldwide, global welfare losses could
exceed $280 billion by 2050, it predicts. For developing economies
where agriculture is the main driver of the economy, it could be a
Climate change could also indirectly affect
regional economies by changing the big players in global food
markets. Areas worst affected by climate change will have less food
to trade, and will instead rely more on imports, which in turn
means taking the biggest welfare hits. On the other hand, regions
where climate change makes conditions more hospitable for growing
crops, welfare levels might get a boost.
Individual impacts can be
To predict these changes in food production and
prices, the research looked at all the main ways climate change
could affect agriculture - simulating the combined effect of rising
temperatures, changing rainfall patterns, altered river flows, and
the growth-boosting effects of having more carbon dioxide in the
The authors warn that looking at individual
impacts of climate change can lead to a "false appreciation" of how
agriculture is likely to be affected in the future. The carbon
fertilisation effect is a good example of
idea is that plants grow bigger when atmospheric
levels of carbon dioxide rise, because plants use carbon dioxide as
one of their main building blocks. At the same time the plants
efficient at using water, meaning they need
to take up less to survive.
This seems like good news, and if it was the
only factor at play, this study suggests more carbon dioxide would
indeed push up global food production and improve welfare
standards. But as the chart below shows, it would be misleading to
conclude on this basis alone that climate change will be good news
Change in global welfare by the 2050s as a result
of changes in agriculture. All factors of climate change shown top,
carbon dioxide fertilisation effect only shown fourth down. Adapted
from Calzadilla et al. (2013).
This graph shows that when all aspects of
climate change are considered, global food production is set to
suffer, in turn leading to big welfare losses.
The modelling used here is quite special,
because as part of looking at how climate change could affect food
production, it also looks at how climate change will affect water
Dr Andy Wiltshire, a Met Office scientist who
co-authored the paper, explained to Carbon Brief:
"Often the impacts of
climate on food and water are treated separately, but really the
interaction is very important as agriculture is one of the dominant
consumers of freshwater".
It's also important to look at water
availability and crop growth together, because irrigation is one
way farmers can adapt to climate change in areas which are
predicted to become drier in the future. Indeed, the modelling
showed that crops grown using irrigation were less vulnerable to
climate change than crops reliant on rainfall.
The study has its limitations, however. These
are the results of just one model, and there are many studies which
suggest food availability could increase in certain
regions. It also doesn't consider how
extreme weather events could change in the future, and what effect
that might have on
Nevertheless, the new study highlights how
complicated the picture is for food production under climate
change. And according to this model, the outlook looks pretty
gloomy - it could well be that the world is a hungrier place in the
Calzadilla et al. (2013) Climate change impacts on
global agriculture. Climatic Change. DOI:
Update - 22/8/13 - The graph on food prices and the
preceeding text was adjusted to reflect that the percentage
calculations, provided by the paper's author, were changes relative
to a world in 2050 without climate change. Previously this article
stated the change was relative to 2001 prices.