The Day After Tomorrow: Could it Really Happen?

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The movie The Day After Tomorrow is loosely based on the theory of “abrupt climate change.” As a result of global warming, the Gulf Stream (part of the Atlantic thermohaline circulation) shuts down. The North Atlantic region starts to cool while heat builds up in the tropics. The result is a severe storm, the likes of which have never been seen, and a dramatic change in the global climate.

Could this really happen? Get the facts from these frequently asked questions below:

What is an abrupt climate change?

Could an abrupt climate change really happen?

What is the difference between “global warming” and “climate change?”

Should we worry about global warming?

Do scientists agree about global warming?

What is the Atlantic thermohaline circulation?

Could climate change shut down the thermohaline circulation?

What are the chances of the thermohaline circulation shutting down?

How can global warming cause cold weather?

If “The Day After Tomorrow” is fiction, what is the truth about global warming?

What can be done about global climate change?

How can I learn more about climate change?

 

What is an abrupt climate change?

When scientists talk about climate change, they are usually referring to “gradual climate change.” In other words, if the planet warms steadily, the climate changes steadily. But there's evidence that some parts of the climate system work more like a switch than a dial: if a certain temperature level is reached, there may be an abrupt and large change in the climate. That’s why some scientists worry about a catastrophic event — like the breakup of the West Antarctic ice sheet or the collapse of the Atlantic thermohaline circulation. To download the National Research Council's Report in Brief on Abrupt Climate Change (PDF), click here.

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Could an abrupt climate change really happen?

Scientists have just begun to study the possibility of an abrupt climate change. But when scientists talk about abrupt climate change, they mean climate change that occurs over decades, rather than centuries. It’s too soon to know for certain whether abrupt climate change could occur, but if it does, it’s not expected to happen within the next several decades.

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What is the difference between “global warming” and “climate change?”

"Global warming" refers to the gradual increase of the Earth's average surface temperature, due to a build-up of greenhouse gases in the atmosphere. "Climate change" is a broader term that refers to long-term changes in climate, including average temperature and precipitation, as well as changes in the seasonal or geographic variability of temperature and precipitation.

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Should we worry about global warming?

This is the best time to worry about global warming, because there’s no longer any doubt in the scientific community that it’s happening, but if we act now, we can still avoid its worst consequences.

Global temperatures have increased by 1°F over the past 100 years. Although this may seem like a small change, it is enough to harm important ecosystems, change rainfall patterns and raise the sea level. Climate models project additional warming of about 2-10° F over the next 100 years. The overwhelming consensus of scientists who study the atmosphere is that this warming is caused primarily by the build-up of greenhouse gases (GHGs) in the atmosphere, mostly from the burning of fossil fuels like coal and oil.

The good news is that there are many ways to reduce GHG emissions inexpensively. Many states and businesses are already taking action. Senators McCain and Lieberman plan to reintroduce their Climate Stewardship Act in the Senate this year. A companion bill, the Gilchrest-Olver Climate Stewardship Act, is now being considered by the House.

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Do scientists agree about global warming?

Although scientists still argue about how fast and how much the atmosphere will warm, the mainstream scientific community agrees on three key points: the earth is warming; the warming is caused primarily by the build-up of GHGs in the atmosphere; and that the warming will continue if we don’t reduce GHG emissions.

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What is the Atlantic thermohaline circulation?

The Atlantic thermohaline circulation, which includes the Gulf Stream, acts like an oceanic conveyer belt that carries heat from the tropics to the North Atlantic region. Warm surface water from the tropics travels northward by the Gulf Stream. As the warm water cools in the North Atlantic, it sinks to the ocean floor, and then slowly moves southward until it returns once again to the tropics. This ocean circulation pattern is caused by differences in water temperature and salinity in the ocean.

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Could climate change shut down the thermohaline circulation?

Global warming is expected to increase ocean temperatures and to increase the flow of freshwater into the ocean through precipitation, run-off, and melting of glaciers. Many climate models have projected that increased surface ocean temperatures and reduced salinity could slow the thermohaline circulation. A few models have projected a complete shutdown of the thermohaline circulation in the case of severe global warming, but this is being debated by the scientific community.

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What are the chances of the thermohaline circulation shutting down?

We don’t yet know the probability of the thermohaline circulation shutting down. It depends on how much and how quickly the atmosphere warms. In general, it is considered possible but not very likely. If it were to occur, it would probably not happen within the next 100 years, and circulation would eventually recover, after decades or centuries.

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How can global warming cause cold weather?

Without the thermohaline circulation, not as much heat would be transported from the tropics to the North Atlantic region. We don’t know how much of this cooling would be balanced by the simultaneous warming in the atmosphere. While it is possible there would be cooling in the North Atlantic region, it is considered more likely that it would continue to warm, but more slowly than the rest of the world.

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If “The Day After Tomorrow” is fiction, what is the truth about global warming?

The truth is that global warming is happening and that it is already too late to avoid some of the effects. Even under the most optimistic circumstances, atmospheric scientists expect global climate change to result in increased flooding and droughts, more severe storms, and a loss of plant and animal species. These events will occur, even if climate change is gradual.

Our report, “A Synthesis of Potential Climate Change Impacts on the U.S.," summarizes the possible effects of global climate change on the natural resources and economy of the United States.

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What can be done about global climate change?

There is no single cause of global climate change and there is no single answer. Most experts believe that technology will provide the solutions. Technologies that reduce emissions (energy efficiency, hydrogen fuels, carbon storage, nuclear energy and renewable energy) and technologies that remove carbon from the atmosphere may all play a role. Government policies that encourage businesses to develop and use these and other technologies are also very important.

Many states and businesses have already found they can reduce emissions while saving money. See "Climate Change Activities in Congress" for a look at what is already being done at the state level, the national level, and in the business community. For a look at a national policy that would combat global warming, read about the Lieberman-McCain Climate Stewardship Act.

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How can I learn more about climate change?

For more detailed information, see our Science & Impacts section and a list of our reports released since 1998. For a good summary of the reasons the United States should join the rest of the world in addressing global climate change without delay, see Eileen Claussen’s Myths and Realities.

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