It's not often I go in for the long blockquote, but Nick Kristof's New York Times column today, filed from Burundi, definitely warrants it:

If we need any more proof that life is unfair, it is that subsistence villagers here in Africa will pay with their lives for our refusal to curb greenhouse gas emissions. ...

People in Burundi have an annual average income of $100, nearly one child in five dies before the age of five, and life expectancy is 45. Against that grim backdrop, changing weather patterns in recent years have already caused crop failures--and when the crops fail here, people starve. ...

Greenhouse gases actually have the greatest impact at high latitudes — the Arctic and Antarctica. But the impact there isn’t all bad (Canada will gain a northwest passage), and the countries there are rich enough to absorb the shocks.

In contrast, the Intergovernmental Panel on Climate Change warned this year that the consequences for Africa will be particularly harsh because of the region’s poverty and vulnerability. It foresees water shortages and crop failures in much of Africa.

"Projected reductions in yield in some countries could be as much as 50 percent by 2020, and crop net revenues could fall as much as 90 percent," the panel warned. It also cautioned that warming temperatures could lead malaria to spread to highland areas. Another concern is that scarcities of food and water will trigger wars.

On a related note, the United Nations released a new report today, concluding that a whole bunch of fertile land will probably crumble into desert within the next generation, especially in Africa and Central Asia--creating an "environmental crisis of global proportions." About 50 million people are at risk of displacement. (A fifth of the population of Mali, for instance, already moves to Ivory Coast during drought years.) Some African countries, presumably, will have to give up trying to feed themselves and start importing food. Not all of that is due to climate change, but some of it is.

Now, even if the world does manage to curb its emissions and stabilize carbon in the atmosphere, some amount of global warming is still on the way, which means that increased droughts or famines due to climate change could still happen. (Of course, reducing emissions will limit the extent of that disaster.) So countries in Africa and Central Asia will still need help adjusting in any case. Back in April, though, the Times had a stunning story about how the world's richest nations are spending billions at home to adapt to the likely effects of climate change, while to tossing pitiful sums at places like Africa, which emits a fraction of the world's greenhouse gases, but will end up bearing the brunt of global warming.

Update: And yes, it is true that climate change can't explain all of the changes. From the Times write-up of the desertification report: "Experts say climate shifts are one of several converging stresses creating the raised vulnerability in dry areas. Others include population growth, diversion of rivers for irrigation and a lack of ability to store water from flooding rains to use when dry times come."