NICHOLAS D. KRISTOF: Our Gas Guzzlers, Their Lives

BUJUMBURA, Burundi

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.

When we think of climate change, we tend to focus on Alaskan villages or New Orleans hurricanes. But the people who will suffer the worst will be those living in countries like this, even though they don’t contribute at all to global warming.

My win-a-trip journey with a student and a teacher has taken us to Burundi, which the World Bank’s latest report shows to be the poorest country in the world. 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. In short, our greenhouse gases are killing people here.

“If the harvest fails in the West, then you have stocks and can get by,” said Gerard Rusuku, an agriculture scientist here who has been studying the impact of global warming in Africa. “Here, we’re much more vulnerable. If climate change causes a crop failure here, there’s famine.”

Guillaume Foliot of the World Food Program notes that farmers here overwhelmingly agree that the weather has already become more erratic, leading to lost crops. And any visitor can see that something is amiss: Africa’s “great lakes” are shrinking.

Burundi is on Lake Tanganyika, which is still a vast expanse of water. But the shoreline has retreated 50 feet in the last four years, and ships can no longer reach the port.

“Even the hippos are unhappy,” said Alexander Mbarubukeye, a fisherman on the lake, referring to the hippos that occasionally waddled into town before the lake retreated.

The biggest of Africa’s great lakes, Lake Victoria, was dropping by a vertical half-inch a day for much of last year. And far to the north, once enormous Lake Chad has nearly vanished. The reasons for the dipping lake levels seem to include climate change.

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. More than five million lives have already been lost since 1994 in wars in Rwanda, Burundi and Congo, and one factor was competition for scarce resources.

“It seems to me rather like pouring petrol onto a burning fire,” Jock Stirrup, the chief of the British defense staff, told a meeting in London this month. He noted that climate change could cause weak states to collapse.

Yoweri Museveni, Uganda’s president, describes climate change as “the latest form of aggression” by rich countries against Africa. He has a point. Charles Ehrhart, a Care staff member in Kenya who works full time on climate-change issues, says that the negative impact of the West’s carbon emissions will overwhelm the positive effects of aid.

“It’s at the least disastrous and quite possibly catastrophic,” Mr. Ehrhart said of the climate effects on Africa. “Life was difficult, but with climate change it turns deadly.”

“That’s what hits the alarm bells for an organization like Care,” he added. “How can we ever achieve our mission in this situation?”

All this makes it utterly reckless that we fail to institute a carbon tax or at least a cap-and-trade system for emissions. The cost of our environmental irresponsibility will be measured in thousands of children dying of hunger, malaria and war.

You are invited to comment on this column at Mr. Kristof’s blog, www.nytimes.com/ontheground.