The world’s richest countries, which have contributed by far the most to the atmospheric changes linked to global warming, are already spending billions of dollars to limit their own risks from its worst consequences, like drought and rising seas.

But despite longstanding treaty commitments to help poor countries deal with warming, these industrial powers are spending just tens of millions of dollars on ways to limit climate and coastal hazards in the world’s most vulnerable regions — most of them close to the equator and overwhelmingly poor.

Next Friday, a new report from the Intergovernmental Panel on Climate Change, a United Nations body that since 1990 has been assessing global warming, will underline this growing climate divide, according to scientists involved in writing it — with wealthy nations far from the equator not only experiencing fewer effects but also better able to withstand them.

Two-thirds of the atmospheric buildup of carbon dioxide, a heat-trapping greenhouse gas that can persist in the air for centuries, has come in nearly equal proportions from the United States and Western European countries. Those and other wealthy nations are investing in windmill-powered plants that turn seawater to drinking water, in flood barriers and floatable homes, and in grains and soybeans genetically altered to flourish even in a drought.

In contrast, Africa accounts for less than 3 percent of the global emissions of carbon dioxide from fuel burning since 1900, yet its 840 million people face some of the biggest risks from drought and disrupted water supplies, according to new scientific assessments. As the oceans swell with water from melting ice sheets, it is the crowded river deltas in southern Asia and Egypt, along with small island nations, that are most at risk.

“Like the sinking of the Titanic, catastrophes are not democratic,” said Henry I. Miller, a fellow with the Hoover Institution at Stanford University. “A much higher fraction of passengers from the cheaper decks were lost. We’ll see the same phenomenon with global warming.”

Those in harm’s way are beginning to speak out. “We have a message here to tell these countries, that you are causing aggression to us by causing global warming,” President Yoweri Museveni of Uganda said at the African Union summit in Addis Ababa, Ethiopia, in February. “Alaska will probably become good for agriculture, Siberia will probably become good for agriculture, but where does that leave Africa?”

Scientists say it has become increasingly clear that worldwide precipitation is shifting away from the equator and toward the poles. That will nourish crops in warming regions like Canada and Siberia while parching countries — like Malawi in sub-Saharan Africa — which are already prone to drought.

While rich countries are hardly immune from drought and flooding, their wealth will largely insulate them from harm, at least for the next generation or two, many experts say.

Cities in Texas, California and Australia are already building or planning desalination plants, for example. And federal studies have shown that desalination can work far from the sea, purifying water from brackish aquifers deep in the ground in places like New Mexico.

“The inequity of this whole situation is really enormous if you look at who’s responsible and who’s suffering as a result,” said Rajendra K. Pachauri, chairman of the United Nations climate panel. In its most recent report, in February, the panel said that decades of warming and rising seas were inevitable with the existing greenhouse-gas buildup, no matter what was done about cutting future greenhouse gas emissions.

Mr. Miller, of the Hoover Institution, said the world should focus less on trying to rapidly cut greenhouse gases and more on helping regions at risk become more resilient.

Many other experts insist this is not an either-or situation. They say that cutting the vulnerability of poor regions needs much more attention, but add that unless emissions are curbed, there will be centuries of warming and rising seas that will threaten ecosystems, water supplies, and resources from the poles to the equator, harming rich and poor.

Cynthia E. Rosenzweig, a NASA expert on climate and agriculture who is a lead author of the United Nations panel’s forthcoming impacts report, said that while the richer northern nations may benefit temporarily, “As you march through the decades, at some point — and we don’t know where these inflection points are — negative effects of climate change dominate everywhere.”

There are some hints that wealthier countries are beginning to shift their focus toward fostering adaptation to warming outside their own borders. Relief organizations including Oxfam and the International Red Cross, foreseeing a world of worsening climate-driven disasters, are turning some of their attention toward projects like expanding mangrove forests as a buffer against storm surges, planting trees on slopes to prevent landslides, or building shelters on high ground.

Some officials from the United States, Britain and Japan say foreign-aid spending can be directed at easing the risks from climate change. The United States, for example, has promoted its three-year-old Millennium Challenge Corporation as a source of financing for projects in poor countries that will foster resilience. It has just begun to consider environmental benefits of projects, officials say.

Industrialized countries bound by the Kyoto Protocol, the climate pact rejected by the Bush administration, project that hundreds of millions of dollars will soon flow via that treaty into a climate adaptation fund.

But for now, the actual spending in adaptation projects in the world’s most vulnerable spots, totaling around $40 million a year, “borders on the derisory,” said Kevin Watkins, the director of the United Nations Human Development Report Office, which tracks factors affecting the quality of life around the world.

The lack of climate aid persists even though nearly all the world’s industrialized nations, including the United States under the first President Bush, pledged to help when they signed the first global warming treaty, the Framework Convention on Climate Change, in 1992. Under that treaty, industrialized countries promised to assist others “that are particularly vulnerable to the adverse effects of climate change in meeting costs of adaptation.” It did not specify how much they would pay.

A $3 billion Global Environmental Facility fund maintained by contributions from developed countries has nearly $1 billion set aside for projects in poorer countries that limit emissions of greenhouse gases. But critics say those projects often do not have direct local benefits, and many are happening in the large fast-industrializing developing countries — not the poorest ones.

James L. Connaughton, President Bush’s top adviser on environmental issues, defended the focus on broader development efforts. “If we can shape several billion dollars in already massive development funding toward adaptation, that’s a lot more powerful than scrounging for a few million more for a fund that’s labeled climate,” he said.

But it is clear that the rich countries are far ahead of the poor ones in adapting to climate change. For example, American farmers are taking advantage of advances in genetically modified crops to prosper in dry or wet years, said Donald Coxe, an investment strategist in Chicago who tracks climate, agriculture and energy for the BMO Financial Group. The new seed varieties can compensate for a 10 or 15 percent drop in rainfall, he said, just the kind of change projected in some regions around the tropics. But, he said, the European Union still opposes efforts to sell such modified grains in Africa and other developing regions.

Technology also aids farmers in the north. John Reifstack, a third-generation farmer in Champaign, Ill., said he would soon plant more than 30 million genetically modified corn seeds on 1,000 acres. It will take him about five days, he said, a pace that would have been impossible just four years ago. (Speedy planting means the crop is more likely to pollinate before the first heat waves, keeping yields high.) The seed costs 30 percent more than standard varieties, he said, but the premium is worth it. Precipitation is still vital, he said, repeating an old saw: “Rain makes grain.” But if disaster strikes, crop insurance will keep him in business.

All of these factors together increase resilience, Mr. Reifstack and agriculture experts said, and they are likely to keep the first world farming for generations to come.

Robert O. Mendelsohn, an economist at Yale focused on climate, said that in the face of warming, it might be necessary to abandon the longstanding notion that all places might someday feed themselves. Poor regions reliant on unpredictable rainfall, he said, should be encouraged to shift people out of farming and into urban areas and import their food from northern countries.

Another option, experts say, is helping poor regions do a better job of forecasting weather. In parts of India, farmers still rely more on astrologers for monsoon predictions than government meteorologists.

Michael H. Glantz, an expert on climate hazards at the National Center for Atmospheric Research who has spent two decades pressing for more work on adaptation to warming, has called for wealthy countries to help establish a center for climate and water monitoring in Africa, run by Africans. But for now, he says he is doubtful that much will be done.

“The third world has been on its own,” he said, “and I think it pretty much will remain on its own.”