"The Day After Tomorrow" Q&A Response

The official NASA response to the 2004 movie with appended information from NSIDC

This content is from the NSIDC archives. It was originally published in May 2004. For more up-to-date information about the cryosphere, please see the following:

The motion picture The Day After Tomorrow may leave many viewers with questions about climate change. In the movie, recent events on earth’s ice sheets and hypothetical future events based on what is known about how climate, oceans, and ice sheets interact, are woven into an exciting but fictitious story about a future climate disaster. The kind of disaster portrayed in the movie is impossible, but the patterns described by the movie have a distant basis in real concepts being discussed by climate scientists, oceanographers, and glaciologists.

The following questions and answers are excerpts from a NASA note to the public regarding the movie. The National Snow and Ice Data Center has appended some links and information for interested visitors to our site, to provide further background on the real scientific discussion, and the facts, related to the movie. Excerpts from the NASA note are in black text, and text added by NSIDC is in blue.

Thank you for your interest.

  1. Did NASA participate in an official manner in the making of this motion picture?
  2. Is climate change (or global warming) happening?
  3. Larsen-B collapsed very quickly, what is the difference [between] that and the Greenland and Antarctic ice sheets?
  4. Are these ice sheets melting?
  5. Is rapid climate change possible? What might cause it?
  6. How rapid is rapid?
  7. Is anyone working on models of the climate system that include the possible effects of the North Atlantic changing? What might happen to the North Atlantic overturning circulation in a global warming scenario?
  8. Could the Younger Dryas happen again?
  9. The movie shows people freezing to death because of a super-storm bringing freezing air from the "upper troposphere." Could that really happen?
  10. Can the ocean cool by tens of degrees over a matter of days?
  11. Can a storm in the Pacific be linked with freak weather in Europe and Asia?
  12. Can ice sheets build up over days?
  13. Is this movie realistic? 

References and links


Question 1: Did NASA participate in an official manner in the making of this motion picture?

NASA was not officially involved with the making of this film.

NSIDC: Nor was NSIDC.


Question 2: Is climate change (or global warming) happening?

NASA: Yes. The causes are complex (GHGs, volcanoes, solar, aerosols). NASA is monitoring many of these from space (SORCE, ACRIMSAT, MODIS, AQUA,TERRA, SAGE II and III, etc.), and working to understand their climate impacts. Temperature change since 1850 is about 0.6 deg C but is a function of many different "forcings" (incl. carbon dioxide).

NSIDC: In the past fifty years, the amounts of greenhouse gases (GHGs) such as carbon dioxide (CO2) and methane (CH4) in our atmosphere have increased rapidly. They now stand at levels far in excess of those indicated by deep ice cores spanning the past several hundred thousand years. A portion of today's CO2 gas contains a 'fingerprint' (i.e., its isotopic make-up) that is consistent with fossil fuel burning. Much of the data describing the ice cores is held here at the Ice Core Data Gateway, managed jointly by NSIDC and NOAA's National Geophysical Data Center.

Further, global warming (caused by a combination of many factors) is having an effect on the world’s ice masses. All but a very few of the mountain glacier regions on Earth are in decline. This decline contributes to the present rate of sea level rise, which is currently about 1.5 mm per year (about a sixteenth of an inch). Summertime sea ice cover over the Arctic Ocean is also declining, and in some areas this ice cover is thinning rapidly. 

Denver Glacier recessionSource: C.L. Andrews. 1912, 1938. Denver Glacier: From the Glacier Photograph Collection Boulder, CO: National Snow and Ice Data Center. Digital Media; Marion T. Millett. 1958. Denver Glacier: From the Glacier Photograph Collection. Boulder, CO: National Snow and Ice Data Center. Digital Media.

You may also be interested in:

  • Douglas, B. C., and W. R. Peltier. 2002. The puzzle of global sea-level rise. Physics Today 55: 35-40.
  • Arendt, A., K. Echelmeyer, W. D. Harrison, G. Lingle, and V. Valentine. 2002. Rapid wastage of Alaska glaciers and their contribution to rising sea level. Science 297: 382-386.

Question 3: Larsen-B collapsed very quickly, what is the difference [between] that and the Greenland and Antarctic ice sheets?

NASA: Larsen-B was a floating ice shelf in the Southern Ocean. Greenland and Antarctica are much thicker and based on land. Monitoring of these ice shelves by ICESAT and plane based altimeters is ongoing.

NSIDC: NSIDC has a Web site that discusses the Larsen Ice Shelf breakup events, and the climate changes leading up to these events.

Floating ice does not displace more seawater when it breaks apart or melts; however, some ice shelves may act as a ‘braking system’ for glaciers that flow into them. When the ice shelves are removed, ice on land may begin to flow faster. This acceleration would contribute to sea level rise.

Warmer air alone may also cause glaciers to speed up. As summers get warmer on the large ice sheets, snow melt at the surface can penetrate through the cracks in the glacier and lower the friction between rock and ice. This process is already underway in some parts of Greenland.

Larsen B on 31 January 200231 January 2002 view larger image (34 KB)

Larsen B on 23 February 200223 February 2002 view larger image (45 Kb)

Larsen B on 07 March 200207 March 2002 view larger image (49 Kb)

For more information, see:

  • Scambos, T., C. Hulbe, M. Fahnestock, and J. Bohlander. 2000. The link between climate warming and break-up of ice shelves in the Antarctica Peninsula. Journal of Glaciology 46(154): 516-530.
  • Zwally, H. Jay, W. Abdalati, T. Herring, K. Larson, J. Saba, and K. Steffen. Surface Melt-Induced Acceleration of Greenland Ice-Sheet Flow. Science 12 July 2002; 297: 218-222

Question 4: Are these ice sheets melting?

Greenland Ice Sheet edge

A researcher observes the edge of the Greenland Ice Sheet in 2001. (Image courtesy of Ted Scambos, National Snow and Ice Data Center, University of Colorado at Boulder)

NASA: There is some evidence of melting in Greenland on the margins, but accumulation near the center. The net melting is still quite uncertain.

NSIDC: A few glaciers in Greenland and Antarctica are increasing in speed; this may be due to increased melt at the surface or the loss of floating ice at their ocean fronts. A smaller number of glaciers in Antarctica are slowing. This contrasts with the melting of smaller glaciers and ice caps, which we know are contributing to sea level rise. But to date, the combined effect of all these glacier changes on sea level is too small to detect. In fact, it is not known to what extent the large ice sheets contribute to present-day sea level rise. The ongoing ICESat mission, which measures ice sheet elevation changes, is intended to help resolve this issue.

The total potential rise represented by the mass of ice in the Greenland Ice Sheet is about 7 meters, and for the Western Hemisphere portion of Antarctica, about 5 meters. These two ice sheets are thought to be more likely to change their ice outflow due to global warming; however, no plausible scenario can be constructed that leads to a significant (several-foot) rise in sea level from these ice sheets in less than a few centuries.

An additional effect expected from global warming is increased snow accumulation at high elevations on these ice sheets. This may partly offset sea level rise due to increased melting and outflow. Please see NSIDC's State of the Cryosphere site for additional information.

You may also be interested in:

  • Rignot, E., and R. H. Thomas. 2002. Mass balance of polar ice sheets. Science 297: 1502-1506.
  • Oppenheimer, M., and R. Alley. 2004. The West Antarctic Ice Sheet and long term climate policy. Climate Change 64: 1-10.
  • Bindschadler, R. A., and C. R. Bentley. 2002. On thin ice? Western Antarctica's ice sheet. Scientific American 287(6): 98-105.
  • Broecker, W. S. 1997. Thermohaline circulation, the Achilles Heel of our climate system: will man-made CO2 upset the current balance? Science 278(5343): 1582-1588.

Question 5: Is rapid climate change possible? What might cause it?

Ocean circulation

view larger image (Image source: Broecker, 1991, in Climate change 1995, Impacts, adaptations and mitigation of climate change, UNEP and WMO, Cambridge press university, 1996.)​

NASA: Yes. At the end of the last glacial period (10,000 years ago), the Younger Dryas event was a very sharp transition around the North Atlantic from warm conditions at the end of the last glacial period back to cold conditions which lasted about 1,000 years before switching back to warm conditions. Scientists think that this was caused by the last major ice sheet in North America collapsing and putting a lot of fresh water into the North Atlantic. This may have caused the North Atlantic "overturning" to slow down, reducing the amount of heat transported toward the pole. There was a smaller event that happened about 8,200 years ago, but that had a much shorter duration and the climate snapped back very quickly. No such events have occurred since then.

NSIDC: Temperature and salinity differences in the world's oceans work together to create what is known as thermohaline circulation. This circulation pattern, illustrated in the figure, acts as a "conveyor belt," slowly overturning the oceans. The strength of the thermohaline circulation is strongly determined by the sinking of the waters associated with the Gulf Stream. This releases vast amounts of heat to the atmosphere, keeping Eurpoe warm.

Readers may be interested in the following scientific articles:

  • Alley, R., et al. 2003. Abrupt climate change. Science 299(5615): 2005-2010.
  • Weaver, A. J., and C. Hilaire-Marcel. 2004. Global warming and the next ice age. Science 304 (5669): 400-402. 

Question 6: How rapid is rapid?

NASA: The cooling took around 200 years to occur, but the warming was faster (on the order of decades).

NSIDC: The figure below shows the evidence for rapid climate change in the Northern Hemisphere at the end of the last ice age, and the climate since then, as it is preserved in an ice core from central Greenland. It shows a record of temperature (measured by oxygen isotope ratios-- a chemical 'thermometer'-- preserved in the snow), and the amount of snow that fell each year.

The figure also shows just how large the change was from the past ice age to our present climate -- and, more importantly, how stable the past ten thousand years have been relative to the ice ages. In fact, nowhere in the ice core record of the past several hundred thousand years can a period of such stability be found. Even so, the relatively small shifts in this period had noticeable effects. The figure illustrates two well-known recent shifts in climate: the Little Ice Age, when the Thames River routinely froze in winter, thick enough to skate upon; and the Medieval warm period, coinciding with the 'Camelot' legends.

All of civilization, from the development of agriculture and the invention of cities, to the Space Shuttle and the Internet, has occurred during the most stable period in the climate record of the past 400,000 years.

Temperature graphClimate changes in central Greenland over the last 17,000 years. Reconstructions of temperature and snow accumulation rate (Cuffey and Clow, 1997; Alley, 2000) show a large and rapid shift out of the ice age about 15,000 years ago, an irregular cooling into the Younger Dryas event, and the abrupt shift toward modern values. The 100-year averages shown somewhat obscure the rapidity of the shifts. Most of the warming from the Younger Dryas required about 10 years, with 3 years for the accumulation-rate increase. A short-lived cooling of about 6°C occurred about 8,200 years ago (labeled 8ka event). Climate changes synchronous with those in Greenland affected much of the world. (Image provided with permission by the National Academy Press, from the report 'Abrupt Climate Change: Inevitable Surprises (2002)'. Copyright © 2003. National Academy of Sciences. All rights reserved. 500 Fifth St. N.W., Washington, D.C. 20001.)


Question 7: Is anyone working on models of the climate system that include the possible effects of the North Atlantic changing? What might happen to the North Atlantic overturning circulation in a global warming scenario?

NASA: Yes. Many groups (including NASA, but also NCAR, GFDL, the Hadley Centre in the UK, DKRZ in Germany, LMD in France and the Japanese), are working with models of the climate that include the oceans, ice and atmosphere. These models are the 'best guess' of how scientists think the different climate processes interact. In some future scenarios some of these models project a slowing down of the North Atlantic overturning, though some do not. Scientists are extremely interested in whether these processes are modeled correctly and what the uncertainties are.


Question 8: Could the Younger Dryas happen again?

NASA: Unlikely. When it occurred previously the world was a very different place with major ice sheets in areas that are now much warmer. The differences in freshwater in the North Atlantic projected for the next 50 to 100 years are much less than the melting that was going on then. However, while this scenario is unlikely, scientists continue to make observations that are relevant to this question and refine the models that are used for climate change scenarios.

NSIDC: Past events, like the Younger Dryas, show that climate can respond in rapid and hard-to-predict ways to slow persistent forcings (a push on the climate system, such as excess heat in the atmosphere or ocean, wind shifts, or density changes in ocean water). One of the major differences between the present-day situation and the past is that the current forcing, greenhouse gases in the atmosphere, is unlike forcings that led to past climate changes (such as changes in Earth’s orbit, or solar influences). Thus, the future course of Earth’s climate is hard to forecast, since no simple analog exists in the recent record of natural climate changes.


Question 9: The movie shows people freezing to death because of a super-storm bringing freezing air from the "upper troposphere." Could that really happen?

NASA: No. Firstly the upper troposphere is not as cold as portrayed (minima near -80 C (-110 F) at about 15 to 20 km), and this cooling is mainly due to the pressure decreasing with height. As air rises it cools due to this effect alone, similarly as it is brought down, it warms up by 6-10 degrees per kilometer.

NSIDC: No, this part of the movie is somewhat far fetched. On the same general subject, changes are expected in atmospheric temperature as well as on the surface. Shown below is a summary. Because GHGs absorb heat in the atmosphere, they change the temperature within its various layers. Finding the pattern illustrated in the diagram of warming and cooling (diagrammed below) would be definitive proof that CO2 and CH4 were the cause of surface warming. But this is not as easy as it may sound; there are not many weather stations in the upper troposphere (aircraft do not do the job well because they affect the air around them). Balloon and satellite data do appear to show the expected trends. The topic is the subject of active scientific debate.

Atmosphere diagramThis diagram shows atmospheric layers and complex temperature trends. The Earth's surface shows a warming trend, while the lower troposphere, from 0 to 8 kilometers (0 - 5 miles) shows slight cooling, the upper troposphere, from 8 to 13 kilometers (5-8 miles) shows warming, and the lower stratosphere, from 13 to 19 kilometers (8-12 miles) is cooling. (Image courtesy of Science@NASA, sponsored by NASA's Marshall Space Flight Center. Curator: Bryan Walls. NASA official: Ron Koczor.)


Question 10: Can the ocean cool by tens of degrees over a matter of days?

NASA: No. The ocean has a very high heat capacity (that is, it needs a long time to warm up or cool down). This is why maritime areas tend to have milder winters than places away from the ocean.


Question 11: Can a storm in the Pacific be linked with freak weather in Europe and Asia?

NASA: No. Some longer-term patterns in the Pacific such as El Niño, do have effects that can be detected statistically in far off regions of world (rainfall in Africa, drought in Australia etc.), but weather systems (such as tropical storms) have very limited extents (around 1,000 miles at most).


Question 12: Can ice sheets build up over days?

NASA: No. The major ice sheets over North America at the peak of the last ice age took tens of thousands of years to build up.

NSIDC: What can happen abruptly in climate change are shifts in air and ocean circulation. Ice sheets and ocean thermal changes require longer to adjust. When climate changed abruptly during the end of the last ice age, air and ocean currents shifted. In the decades and centuries that followed, these changes gradually affected the ice sheets and deep ocean. Ice sheets that were in equilibrium with the previous ice age climate were not compatible with the new climate; or, conversely, cool areas in northern Canada or Scandinavia that had been ice free began retaining a layer of snow through every summer. Slowly, over centuries, ice sheets grew, or retreated, in response to the climate changes.

This process of shifting climate and changing ice sheets is happening today. In the Antarctic Peninsula, climate has warmed to the point where ice shelves that were stable there for many centuries are no longer stable. The northern most limit for ice shelves has moved south over the past two decades by about 100 miles. (note that ice shelves respond to climate change more rapidly than large ice sheets)


Question 13: Is this movie realistic?

NASA: No.

NSIDC: While aspects of the movie have a distant basis in fact and real theories of climate change, the film greatly compresses and exaggerates events. Scenarios that take place over a few days or weeks in the movie would actually require centuries to occur. Nevertheless, climate change is real, and is having an effect on Earth’s ice and oceans. Not tomorrow, or the day after, but today.

Arctic sea ice concentration anomalies in September 2002 and September 2003Sea ice extent and concentration anomalies relative to 1988-2000. In September 2002, satellite data showed that sea ice extent was 4 percent lower than any previous September since satellite monitoring began in 1978. Source: Fetterer, F. and K. Knowles. 2002. Sea Ice Index. Boulder, CO: National Snow and Ice Data Center. Digital media. 

You may also be interested in reading:

  • Serreze, M. C., J. A. Maslanik, T. A. Scambos, F. Fetterer, J. Stroeve, K. Knowles, C. Fowler, S. Drobot, R. G. Barry, and T. M. Haran. 2003. A record minimum arctic sea ice extent and area in 2002. Geophysical Research Letters 30(3): 1110, doi: 10.1029/2002GL016406.
  • Sturm, M., D. K. Perovich, and M. C. Serreze. 2003. Meltdown in the north. Scientific American 289(4): 60-67.

The following links from NSIDC help provide further information about the scenarios portrayed in the movie, The Day After Tomorrow.


Additional external links:


Journal articles and papers referenced in this Q&A:

  • Alley, R., et al. 2003. Abrupt climate change. Science 299(5615): 2005-2010.
  • Arendt, A., K. Echelmeyer, W. D. Harrison, G. Lingle, and V. Valentine. 2002. Rapid wastage of Alaska glaciers and their contribution to rising sea level. Science 297: 382-386.
  • Bindschadler, R. A., and C. R. Bentley. 2002. On thin ice? Western Antarctica's ice sheet. Scientific American 287(6): 98-105.
  • Broecker, W. S. 1997. Thermohaline circulation, the Achilles Heel of our climate system: will man-made CO2 upset the current balance? Science 278(5343): 1582-1588.
  • Douglas, B. C., and W. R. Peltier. 2002. The puzzle of global sea-level rise. Physics Today 55: 35-40.
  • Oppenheimer, M., and R. Alley. 2004. The West Antarctic Ice Sheet and long term climate policy. Climatic Change 64: 1-10.
  • Rignot, E., and R. H. Thomas. 2002. Mass balance of polar ice sheets. Science 297: 1502-1506.
  • Scambos, T., C. Hulbe, M. Fahnestock, and J. Bohlander. 2000. The link between climate warming and break-up of ice shelves in the Antarctica Peninsula. Journal of Glaciology 46(154): 516-530.
  • Serreze, M. C., J. A. Maslanik, T. A. Scambos, F. Fetterer, J. Stroeve, K. Knowles, C. Fowler, S. Drobot, R. G. Barry, and T. M. Haran. 2003. A record minimum arctic sea ice extent and area in 2002. Geophysical Research Letters 30(3): 1110, doi: 10.1029/2002GL016406.
  • Sturm, M., D. K. Perovich, and M. C. Serreze. 2003. Meltdown in the north. Scientific American 289(4): 60-67.
  • Weaver, A. J., and C. Hilaire-Marcel. 2004. Global warming and the next ice age. Science 304 (5669): 400-402.
  • Zwally, H. Jay, W. Abdalati, T. Herring, K. Larson, J. Saba, and K. Steffen. Surface Melt-Induced Acceleration of Greenland Ice-Sheet Flow. Science 12 July 2002; 297: 218-222.

Additional journal articles and papers:

  • Hansen, J. 2004. Defusing the global warming time bomb. Scientific American 290(3): 68-77.
  • Schwartz, P., and D. Randall. 2003. An abrupt climate change scenario and its implications for the United States National Security: a report commissioned by the U.S. Defense Department.