It’s Raining Now in Southern Sudan, And the Climate Models Tell Us?

There is an article at the Science and Development Network Website indicating that some climate models predict Africa’s Sahel region will get wetter, while others predict it will get drier given global warming:

“Scientists initially believed that the decline in rainfall was caused by overgrazing and people clearing vegetation to make way for more farming and herding. But since the mid-1980s, several computer models have suggested that changes in the surface temperature of the oceans have changed the dynamics of the West African monsoon and are therefore to blame.

This hypothesis has gained widespread support but there still some disagreement. Different models point the finger at different oceans — some say the influence of the Indian Ocean is most important, others the difference between the North and South Atlantic.

Most scientists agree that the greenhouse gases and aerosols that human activities release into the atmosphere are partially to blame for changing ocean temperatures.

The question, then, is how this will affect future rainfall. Again, the answers depend on the models used.

… Understanding why the models predict such widely divergent futures “is a scientific priority that requires really getting into the bowels of the models” says Alessandra Giannini, a climate expert at Columbia University in the United States.

“There must be something in the models’ physics that is causing them to respond differently.”

For instance, several researchers have pointed out that many of the models show cooler present-day sea temperatures near the Americas and warmer ones close to Africa when the reality is the other way around — suggesting that the models are flawed.

Hurrell attributes the difficulties in modelling future Sahel rainfall to the “multiple competing influence of [factors that have] comparable importance”.

His research with Hoerling suggests that global sea-surface temperatures play a strong, and possibly dominating, role in determining how much rain falls in the Sahel — more so than, for instance, temperatures above Africa.”

The semi-arid Sahel stretches across North Africa south of the Sahara and is well know for its droughts and famines.

I have a friend currently working as a nurse in war torn southern Sudan, in a recent email she told me it was raining:

“It is Sunday and I have some computer time at last. And I am not on call, so hopefully will have some time to myself. After saying last Sudanmail how awful the heat and the dust was, we are now experiencing heat and mud. It has bucketed down for three days now, and the soil has turned to thick, black mud which builds up on the bottoms of your sandals till you are walking on platforms.

Great excitement for the distribution of gum-boots and raincoats last week, so now we all clomp around in boots, but the raincoat is too much of a sauna.

… The rain means the computers don’t charge as there is no solar energy, so we have been short of power. I think there is another 4 months of rain ahead, so I had better get used to power shortages and mud.”

So solar is not so good, when its raining nonstop.