In the Netherlands -- where holding back the sea is a way of life -- architects are designing homes that will rise up and bob like houseboats when the North Sea rises.

In the far north, shipping lanes long frozen are opening up, and the Northwest Passage is no longer a dream. The red fox, common in New England, may out-compete its snow-white cousin, the Arctic fox, when the Great North becomes a warmer place to live.

And across the United States, humans will be getting used to droughts and floods and spells of violent weather. There will be more rain in some places, more desert in others.

These are just some of the changes ahead chronicled in "Climate Change," a strong, new exhibit at the American Museum of Natural History in New York City.

The exhibit is an attempt to illustrate what co-curator Michael Oppenheimer calls "the key issue of the 21st century.''

"I say that with a full understanding of the other important issues: terrorism, the two wars the United States is engaged in, the global financial crisis," said Oppenheimer, professor of geosciences and international affairs at Princeton University.

"But as challenging as they are, I think they're also short-term problems. We will be dealing with climate change long after we solve the financial crisis."

"It's a very, very complicated story to tell," said Edmond Mathez, a curator of earth and planetary sciences at the museum, who was the lead curator of the exhibit.

It's essentially a story about how humans use energy and the consequences of that use.

But it's also a story about how human inventiveness may steer the Earth away from the worst effects of global warming -- severe droughts and flooding, the mass extinction of species, and human dislocation on a grand scale.

"If we continue on our current course, it will lead to significant droughts and a significant change in food supplies," Mathez said. "And there will be stresses we can't anticipate, like wars."

Mathez said he and the museum began planning the exhibit two years ago, in part to try to correct some of the gross misinformation about climate change then in place.

The scientific consensus on the issue had already coalesced. Researchers had seen the data. They knew global warming was occurring and that human activity -- burning coal and oil, which releases mass amounts of carbon dioxide into the atmosphere -- was a major contributor.

They also knew that there was a vast amount of misinformation on the subject.

"It's gotten better," Oppenheimer said. "But we're in the age of the Internet. Once something gets posted, it never disappears."

The museum seemed a good place to tell the story of climate change, Oppenheimer said, simply because so many people visit it -- about 4 million a year.

"We could be deepening the message, but also broadening it, and reaching people who might not be paying attention," he said.

The two said they and the museum staff worked hard to tell the story with arresting visual displays and dioramas, while remaining absolutely accurate to the scientific knowledge available.

"We stand behind everything in the exhibit," Mathez said. "All the science in the exhibit came from the literature. It's not an issue of belief on our parts. Nothing we say is controversial."

"We wanted to be very careful about admitting what we don't know," Oppenheimer said.

What science does know about global warming is this: Over the past century, the amount of carbon dioxide in the atmosphere has risen dramatically.

Using a variety of methods, including polar ice core samples, tree rings, and air samples taken at the Mauna Loa Observatory in Hawaii since 1958, scientists have evidence there is more CO2 in the atmosphere now than there has been for the past 800,000 years.

CO2 -- the product of burning fossil fuels -- acts as an insulator in our atmosphere, trapping heat. While we need some CO2 in the atmosphere to keep Earth's climate livable, those levels are now driving climate change, the exhibit says.

The signs are all around us. In the U.S., storms have become more unstable since 1948. In 2003, about 35,000 people died throughout Europe because of a heat wave that took civic leaders by surprise.

Wildfires in North America are becoming more common and more destructive -- earlier springs mean the woods dry out earlier.

Climatologists have been constant in saying that climate change won't simply be a matter of summers getting a little warmer and longer. It will probably mean more violent weather around the globe, and vast areas of Africa becoming desert. The American Southwest may become hotter and drier than it already is.

Climate change will also mean rising sea levels, a change already under way. Some of the world's great delta regions -- Bangladesh, the Nile Delta in Egypt, the Mekong River Delta in Vietnam, and the Mississippi River delta in the U.S. -- may all permanently flood, bringing major ecological changes to those regions.

The exhibit admits scientists still don't know the impact of climate change on the oceans. They do know oceans act as enormous CO2 sponges, holding 50 times the CO2 the atmosphere does, and mitigating the increase of global greenhouse gases.

They also know oceans are becoming warmer and more acidic because of CO2 levels.

But right now they don't know what the impact of that will be. Some coral beds are dying and further loss of these beds -- great incubators for marine life -- could be part of a great environmental change in sea life.

Mathez said scientists don't know whether the warming of the seas will someday prevent them from absorbing CO2 and carrying it deeper into the ocean waters.

They also don't know the consequence of the permafrost -- the frozen ground that makes up 20 percent of the Earth's land mass -- being warmed.

Permafrost is a huge reservoir of methane, another greenhouse gas. It's feared if the permafrost melts and releases that methane, it could greatly accelerate climate change, creating a self-perpetuating cycle -- more warmth, more melted permafrost, more methane, more warmth.

But the exhibit is not predicting doomsday.

One section goes into detail about the small changes people can make in their lives to reduce the amount of CO2 going into the atmosphere.

It concludes with a display of the alternative energy sources now available -- solar, wind, geothermal, hydropower -- that can be used to greatly reduce the use of fossil fuels worldwide. Some of the technology to do this is now readily available.

Other energy sources -- like harnessing the tides, ocean waves and river currents to generate power -- are just beginning to be explored.

And there is another technological fix -- pumping the CO2 we produce deep underground and keeping it out of the atmosphere altogether. While this is untested, some researchers estimate we could store 90 percent of our CO2 emissions this way.

Mathez and Oppenheimer said what's now needed is the global political will to commit to these new technologies and new sources of energy. Grassroots groups are important in forcing politicians to act, but for serious change to occur there has to be a commitment from leaders.

Again, this is not inconceivable -- after the oil crises of the 1970s, the leaders of Denmark committed their country to energy efficiency and to finding alternative sources of power. Today Denmark produces 20 percent of its power from wind turbines -- compared to .07 percent in the U.S. -- and Danes consume about half the power of their American counterparts.

So what's needed is commitment from ordinary people and politicians.

"It has to come from both directions," Mathez said.

Contact Robert Miller


or at (203) 731-3345.

IF YOU GO What -- "Climate Change" exhibit. Where -- The American Museum of Natural History, Central Park West at 79th Street, New York City. When -- Until Aug. 19, 2009. Hours -- 10 a.m. to 5:45 p.m., seven days a week. The museum is closed Thanksgiving and Christmas Day. Cost -- $15 for adults, $8.50 for children age 2 to 12, $11 for seniors or students with ID. Information -- Call the museum at (212) 769-5100 or go to its Web site at OVER THE CENTURIES 1600 A.D. About 550 million people on Earth. Global economy of $77 billion. 274 parts per million carbon dioxide in Earth's atmosphere. 1800 A.D. 813 million to 1.1 billion people. $175 billion global economy. 284 parts per million carbon dioxide in the Earth's atmosphere. 1900 A.D. 1.5 billion to 1.8 billion people. $1.1 trillion global economy. 50,000 cars on the world's highways. 300 parts per million carbon dioxide in the Earth's atmosphere 2000 A.D. 6.07 billion people. $41 trillion world economy. 700 million cars on the world's highways. 369 parts per million carbon dioxide in the Earth's atmosphere.