Study links hot weather to violent conflict in Africa
- 10 Nov 2014, 20:57
- Robert McSweeney
Analysis of violent events in the past 30 years in
sub-Saharan Africa reveals a link to high temperatures, a new study
finds.
However, the researchers say the impact of climate is
less important than many other social and economic
factors.
Heated debate
The relationship between climate change and conflict has
prompted much heated debate among academics. A recent
review of 50 studies found they consistently supported the
theory that changes in climate can cause conflict, but the
conclusion was roundly
criticised by a group of 26 other researchers.
On the face of it, the connections might seem obvious. Climate
change risks exacerbating competition for natural resources,
causing displacement through climate extremes and natural
disasters, or just making it harder for governments to manage
existing problems.
Yet there is limited evidence of a direct link, partly because
there are so many political, social and economic factors involved
in conflict. In its recent
synthesis report, the IPCC says there is "medium confidence"
that climate change can indirectly increase risks of violent
conflict by amplifying poverty and economic shocks.
These other factors are considered alongside climate in a new
study published in Proceedings
of the National Academy of Sciences, which analyses high
temperature extremes and violent events in sub-Saharan Africa.
Violent events
The study uses temperature and rainfall data alongside a dataset of armed
conflict events from civil wars and periods of instability, for the
period 1980 to 2012. The maps below show this data plotted as 100km
grid squares across sub-Saharan Africa.
On Map A, the dark pink areas show where the highest number of
violent events have occurred in recent decades. For example, the
borders between the Democratic Republic of Congo and Rwanda and
Burundi show a large patch of dark pink, as does much of Zimbabwe,
and Somalia on the westernmost point of Africa.
Map showing number of violent events in
sub-Saharan Africa between 1980 and 2012. O'Loughlin et
al. (2014)
Maps B and C show how the number of 'hot' and 'dry'
months compares with the long-term average. You can see that much
of central and eastern Africa has been warmer than usual, while
southern areas and the Sahel have been drier than
expected.
Maps showing B) number of 'hot' months, and C)
number of 'dry' months for sub-Saharan Africa between 1980 and
2012. Maps B and C show data as a ratio compared to the expected
number of 'hot' and 'dry' months from the long-term average. In all
maps, the darker colours show the areas affected more
severely. O'Loughlin et al. (2014)
The Sahel
The researchers combined the climate and
conflict datasets to see if they could find any relationships
between them. Their results show a 10 per cent increase in violent
conflicts with every one standard deviation increase of
temperature, but no link with high or low precipitation.
In other words, the researchers found there were
more conflicts when it was hotter. However, they couldn't tell
whether heat caused the conflicts or if the two were linked by
other factors.
Further analysis looking at five specific
regions of sub-Saharan Africa (see map below) reveal that the
temperature relationship is only statistically significant for the
Sahel. The researchers think this strong link was the reason they
found the continent-wide relationship in the first
instance.
Regional definitions for sub-Saharan Africa.
O'Loughlin et al. (2014)
The results also show that the type of conflict
linked to higher temperatures is primarily against civilians. The
researchers suggest this could be because responses to extreme
weather are immediate rather than long-term, making it more likely
to be small-scale conflicts such as land seizures or cattle-raiding
than organised warfare.
Predicting conflict
The study also looks at whether they could use
temperature extremes in a model to predict violent
events.
The researchers find that the climate is less
important than a number of political, social and economic factors
for predicting conflict. Factors considered more important include
existing conflict in neighbouring areas, socio-economic well-being,
distance to national borders, and capital city location.
Alex Randall, project manager of the Climate Change and Migration
Coalition, explains the significance of the findings:
"This has important
implications for future research and peacebuilding. It suggests
that some conflicts in some areas might be sensitive to climate
change, while others are not. It would be a mistake to design
policy assuming that climate change will have a universal and
consistent impact on conflict."
Halvard Buhaug, a research professor at the Peace
Research Institute in Oslo (PRIO), says the research is a step
forward:
"[The study] showcases
the direction in which research in this area is, and should be,
moving. Using high-resolution data and a careful research design
that allows comparison of the influence of climate impacts with
those of socioeconomic and political determinants of
conflict."
O'Loughlin, J. et al. (2014) Effects of
temperature and precipitation variability on the risk of violence
in sub-Saharan Africa, Proceedings of the National Academy of
Sciences, http://www.pnas.org/cgi/doi/10.1073/pnas.1411899111