Does climate change cause a drought? Does it cause a famine?
- 08 Aug 2011, 13:50
- Christian Hunt
It's worth reading
a piece discussing the Somalian drought and accompanying famine
by Chris
Funk, a researcher at the University of California, which
neatly illustrates how the 'did climate change cause extreme
weather event X' question isn't particularly helpful.
Last year, his team essentially predicted the drought in Horn of
Africa which has led to a famine. And there's a link to climate
change. But note the different components to the analysis:
Last summer, our group was meeting when
a La Niña weather system was forecast. We knew that such an event
could bring trouble, and we issued an alert that East Africa might
experience severe droughts.
We based this conclusion on information from three sources. First,
we knew that La Niña events are commonly associated with weakened
rains in the Horn of Africa from October to December.
Second, from work on the ground, we knew that persistent poor
rains at the end of the past decade, combined with high food
prices, had weakened the population's resilience to food
emergencies.
And third, research has linked warming in the Indian Ocean as a
result of climate change to drying of March-to-June rains in East
Africa. This warming has intensified the negative impact of La Niña
events; it was the chance that both the autumn and spring rainy
seasons could be affected, back to back, that really concerned
us.
So according to Funk, here's a social problem (famine), driven
by an extreme weather event (drought), occurring in a particular
context of poor rains and high food prices. The drought is a result
of changes in a natural weather system (La Nina), which may have
been dangerously intensified by climate change.
You couldn't say that climate change 'caused' the drought or the
famine. But you also couldn't say that it was unrelated. And that
highlights a basic problem with the way we discuss causation,
climate change, and extreme weather. There's a logical hiccup
in saying that because we can't pinpoint climate change as 'the'
cause for a specific extreme weather, there is no link.
It's going to be necessary to point this mistake out where it
occurs, because the things which make it hard to predict extreme
weather in advance - the difficulty of doing regional climate
change predictions, and the difficulty of short term weather
forecasting of specifics compared with long term climate
forecasting of averages - aren't going to change any time soon.
You can donate to the Disasters Emergency Committee,
which is co-ordinating funding to aid relief in the Horn of Africa,
here.