In June 2007 Mr Ban Ki Moon, General Secretary of the UN, wrote an editorial in the Washington Post attributing the conflict in Darfur to climate change. Mr Moon stirred up a good deal of controversy in asserting that resource competition, or eco-scarcity, was responsible for the outbreak of internal conflict in early 2003. On the one hand, he was lauded by climate NGOs, for profiling the security and humanitarian implications of climate change. On the other hand many commentators took issue with his absolution of the Sudanese government and non-governmental militias.
But, is Mr Moon’s assertion scientifically validated? Kevane and Gray (2008) argued that rainfall measurements do not support Mr Moon’s contention that precipitation has fallen 40% since the 1980s. Their data suggest the 1980s was the low point of the drought and that rainfall has since rebounded. Heumann and others (2007), report a greening of the Sahel since the 1980s. So what about Darfur?
Using satellite data from 1981-2006 we can identify the relative healthiness of vegetation using a measure called the Normalised Difference Vegetation Index (NDVI). A high NDVI value (around 0.7) indicates healthy vegetation. A low NDVI value (< 0.2) would indicate poor vegegation or desert. The vegetation in te region is highly seasonal so we can reduce the amount of data we need to the height of the growing season in September. If we average the data over Western Darfur State we see an increase in NDVI from the 1980s to the early 2000s. In Northern Darfur State the NDVI values barely change. There is a slight rise but the NDVI is very low indicating desert conditions.
Figure 1. The September NDVI anomaly for Wesetrn Darfur State (Green) and Northern Darfur State (Blue). The anomaly is calculated as the mean September NDVI (1981-2006) minus the annual September NDVI. Negative values indicate an increase in NDVI relative to the time series mean. Note the inverted y-axis.
These results are preliminary but it would appear that Mr Moon’s attribution of the conflict to climate change was premature. True, the region experienced drought and consequently eco-scarcity in the 1980s. However, the conflict broke out two decades later during a period of improved ecology and climate.
Short Reference List
Kevane and Gray (2008) Environ. Res. Lett. 3
Heumann, Seaquist, Eklundh and Jönsson (2007) Remote Sens. Environ. 108