The science behind "The Day After Tomorrow"?

Question

We watched The Day After Tomorrow in science class and I have a lot of questions that I need answered.

1. What current is disrupted that eventually leads to a climate change?

2. What caused that current to be disrupted?

3. What is causing global warming?

4. "Global warming can ultimately lead to a state of Global Cooling." Explain how this would occur.

5. Is fresh water more or less dense than salt water and how does this effect the current?

6. Are tornadoes really possible in LA? Explain why they happen.

7. How do ice sheets advance from the Northern Hemisphere and how does this signify that we are in an ice age?

8. How and where are hurricanes formed?

9. Does the eye of the storm usually form over land or water? Why?

10. Do storms in the northern hemisphere move clockwise or counterclockwise? Did the movie depict this accurately? What rotation effect causes these storms to move in the direction that they do?

Answer 1

TDAD was science fiction but the media treated it as a fairly serious possible scenario.

1. The thermohaline circulation has been interrupted in the past but it took enormous quantities of freshwater to do so, a lake that occupied an area many times the size of the Great Lakes in the US drained suddenly. An event like that is just not possible today since there is no freshwater source of that size.

2. Melting glaciers interrupted the cycle in TDAD, the fresh water freezes at higher temp than seawater and flows at a different height. Again, this can't happen today.

3. The sun causes nearly 100% of the warming on Earth, some of it is reflected back out into space after it reaches us but greenhouse gases trap certain wavelengths, keeping it inside the atmosphere where it can cause warming.This can be demonstrated in a lab very successfully but in the real world the impact is unknowable at present but minimal based on recent history.

4. This is simple. It always gets warmer right up until the time at which the ice age returns. We're currently near the close of an interglacial period and the ice age could return at any time. What causes this change is generally considered to be due to variations in the Earth's orbit around the sun, which isn't influenced by any greenhouse gas.

5. Freshwater is less dense than seawater and freezes at a lower temp.

6. Tornadoes are theoretically possible anywhere but the weather patterns in human memory tend to make us think this isn't true.

7. When it begins to cool the ice begins to advance. It advanced enough in a single winter, 2007-2008, to make up for most of the losses that took decades to produce. When an ice age causes glacier expansion there is nothing humans can do about it but move out of the way. A mile-high glacier simply can't be dealt with by our science.

8. Hurricanes are complex but like any storm they form due to the differences in temperature of various air and ocean currents, the cold and warm air and water interact and the result can be anything from a tornado to a cyclone or a hurricane.

9. The eye of the storm exists both on land and sea in a hurricane, it moves with the storm so I don't understand your question.

10. Large storms rotate in a counter-clockwise direction in the northern hemisphere, the opposite in the south. What an individual tornado or small event may due is impossible to predict since it isn't subject to the coriolis effect like a large weather system. I don't recall what TDAD said about their storms but I doubt it was accurate.

11. The most laughable part of TDAD was the drawdown of air from the stratosphere to ground level. It's a bit hard to pull a near-vacuum to ground level and expect it to have any impact, since there's nothing there. It's a bit like putting a single ice cube into a bathtub of hot water, it won't have much of an impact, only in this case it's not even ice, just cold air.

12.  CO2 and other greenhouse gases do cause warming, that can be demonstrated in a lab. But in the outside world there are many ways nature deals with these gases and the exact amount of warming each will actually cause is less clear. Each succeeding CO2 molecule will block less infrared than the prior one until a saturation point is reached for that particular bandwidth at which point no more warming will result from adding more CO2. CO2 levels have been as much as 20 times higher, 2000%, and temp was only 7 celsius warmer than it is today.

13. Look at the past. It gets warm until the ice age returns, that's been the pattern for a very long time. It isn't going to change no matter how much we'd like it to, when the ice age returns the population will likely drop to about 10% or less of it's current levels, much worse than any warming would cause.

Plants and animals prefer warm climates, even polar bears have survived interglacial periods much warmer than this one is likely to get. More CO2 means plants need less water to grow, yet as ice melts there is more water for the water cycle and deserts shrink. The Sahara has already receded in recent years. All the claims about warming causing more severe weather are unsubstantiated, there is no evidence one way or the other. Ask in 100 years.

14. An ice age usually takes decades to get going but it can happen so fast that a mammoth can be trapped in ice with fresh grass in it's mouth.  I've already pointed out many inaccuracies but if all the ice on Earth melted at once, the sea level would rise. But an event that could cause that to happen would be so catastrophic (asteroid impact or super-volcano eruption) that high tides would be the least of our worries.

Answer 2

I have a question for you.

Are you in a government school, or a private school?

No offense to you, just the school.

My money is on the government, I would also wager that you watched an Inconvenient Truth. Did you know that IT used a scene, flying through the arctic on a helicopter, from the DAT?

Answer 3

There is no science behind this Hollywood creation, however there is definitely an agenda.