Is climate change to blame for famine in the Horn of Africa?

Duncan Green in the PovertyMatters blog at the Guardian (UK): So is famine in the Horn of Africa linked to climate change or not? The question arises whenever "extreme weather events" – hurricanes, floods, droughts – hit our TV screens. It's impossible to answer with a simple yes or no – but here's what we think we know so far.

The current drought conditions have been caused by successive seasons with very low rainfall. Over the past year, the eastern Horn of Africa has experienced two consecutive failed rainy seasons. According to surveys of local communities, this is part of a long-term shift. Borana communities in Ethiopia report that whereas droughts were recorded every six to eight years in the past, they now occur every one to two years.

...The historical record does not "prove" that the current drought is directly attributable to climate change. True, there are now a few cases in which scientists have been able to estimate the extent to which man-made climate change has made a particular extreme weather event more likely, but these exercises require reliable long-term weather data that only exists for Europe and North America – no such studies as yet exist in the case of the current drought.

What about the future? Globally, climate change modelling projects an increase in the frequency and severity of extreme weather events like droughts and floods. In the absence of urgent action to slash global greenhouse gas emissions, temperatures in the region will probably increase by 3C-4C by 2080-99 relative to 1980-99.

...The conclusion? Attributing the current drought directly to climate change is impossible, but in the words of Sir John Beddington, the UK government's chief scientific adviser, in a talk at Oxfam last week, "worldwide, events like this have a higher probability of occurring as a result of climate change". Moreover, unless something is done, the current suffering offers a grim foretaste of the future – temperatures in east Africa are going to rise and rainfall patterns will change, making a bad situation worse....

April 1, 2011 - June 30, 2011. Drought has plunged East Africa into the worst food security crisis Africa has faced in 20 years. More than 11.5 million people are currently in need of food aid in Djibouti, Kenya, Somalia, and Ethiopia. The number is projected to rise, and this image illustrates why.

The image shows plant growth during the growing season for the crop normally harvested in June and July. The image was made with observations from the Advanced Very High Resolution Radiometer (AVHRR) on the NOAA-18 POES satellite, which records the amount of light plants in a broad region absorb during photosynthesis. Where there were more leafy photosynthesizing plants than average, the image is green. Brown indicates that plants were sparser or growing less than average. Broad swaths of East Africa are brown, pointing to poor plant growth during the growing season. The crop grown during this period is typically planted in March or April, when the first rains of the year fall. In 2011, the rains were late, falling in late April and May, and inadequate. The crops were planted late and are only now being harvested. In southern Somalia, currently the most severely impacted region, the harvest is expected to be 50 percent below average, says the Famine Early Warning Systems Network (FEWS NET). Pastures are also sparse, putting stress on livestock. The poor harvest and lack of pasture in July compounds existing food security problems.