A New Ice Age?

barakn writes "Scientists have savaged the new movie The Day After Tomorrow, which depicts global warming causing a new ice age and freezing New York solid. The movie follows on the heels of a report to the Department of Defense in February, written by two guys who are not climatologists, about the implications of global warming triggering the growth of ice sheets in the northern hemisphere. There is a plausible theory which suggests that melting ice may release enough fresh water to halt circulation of warm water from the Gulf Stream, thus significantly cooling Europe and the east coast of North America. Note that this theory depends on melting ice, not growing ice, which may be one reason scientists find the ice age scenario so hard to swallow. New satellite evidence suggests a part of this circulation may already be slowing down. Those on the North American west coast will not have to worry about ice sheets, but changes in Arctic ice could mean the western drought will be permanent. For those of you who would rather do something before it's too late, iron seems to work, but the long-term ecological implications are still unknown."

Comments

Re:Wait... so you're telling me...

[mabinogi]

Actually, that makes me wonder if he was actually too close to the mark for the scientists to handle...

You don't see scientists getting up in arms about movies like The Core, or Armageddon so why are they all defensive about this one?

Re:Wait... so you're telling me...

[Ralconte]

Ah, movie science, so you haven't been here, have you? http://www.intuitor.com/moviephysics/

Maybe it is because we are skeptical...

[SerpentMage]

Sure global warming may be happening... BUT and this is probably why the slashdot people are laisse faire, maybe it is part of the overall scheme of things by none other than mother nature.

When that little warming period and ice age hit, which was not caused by humanity, would the arguments not be the same? EG would the green people would be saying to stop burning all of those fires to heat homes?

Frankly I think the only real way of stopping global warming is to kill off about 2/3 of our planet. There are just too many of us.

Let me give you an example. Germany, which is trying to be green installed a huge number of wind powered generators in the North Sea. They have just found out that because of all those generators the coast is getting 10% more sunshine and 10% less rain. I then ask the question, are we not dammed if we do and dammed if we do not?

So unless you are ready to volenteer your life in the name of "humanity" nothing much is going to change.

BTW I do not agree with your quote as planet Earth has withstood worse things than humans and continued. What might not survive are the humans!

The Cassandra effect and Public discourse (long)

[uncadonna]

This topic is amazingly timely for me as I'll be giving a presentation to a group of geophysicists on Tuesday about abrupt climate change in the last 100,000 years and the upcoming 10,000.

When I first got into this business in the early 90s I spent a lot of time discussing these topics on sci.environment.

It may be worth pointing out that climate change over the past decade has panned out pretty much as was expected ten years ago. It's interesting that this hasn't affected the cerdibility of the field very much.

I've dabbled a bit in sci.environment again in the last few months, but it's been a lot less satisfying. Ten years ago I had the privilege of getting into flame wars with no less than John McCarthy, as well as many other less famous but comparably intelligent, very well-informed conservatively inclined people.

To be sure, there were also many throughly propagandized folks, mostly aligned in two opposing camps, but it was possible to have a serious debate and even, once in a while, score a point.

The conversation on Slashdot is only marginally better than the decaying thrashings on sci.environment. It's better because most people here are grinding different axes, and so their ill-informed commentary is less shrill and confrontational.

There's a hell of a lot of misinformation going around here, though. It's pretty discouraging to see what gets moderated to 5, insightful or informative.

Even the hacker community, chastened though it should be by the ways in which writing code makes you face your mistakes, is sadly overconfident about its opinions. People make broad and confident statements on matters where, (obviously to those few of us here who are serious students of the matter) they know very little. Moderators sharing the politics of the poster mod these up to "insightful" ore even worse "informative".

Let me review the settled science. There's a lot that's unsettled, but when I see these points debated I despair for democracy:

• Climate, defined as the long-term average behavior of the atmsophere, ocean and ice, shows a lot of natural variability in response to perturbations in forcing.
• While the underlying principles of climate physics are not exotic, the number of degrees of freedom of the system makes the system behavior difficult to predict in detail
• While details are difficult to predict, certain global constraints (mass, energy and angular momentum conservation) allows more confident predictions about the big picture than about the details.
• Complex computer models are the only way to get any idea about the details, but the global picture can be discussed using old-fashioned paper-and-pencil models
• Human behavior is altering the energetic balance of the atmosphere at a larger rate than is normal in nature, with very rare exceptions such as asteroid impacts.
• The simple calculations indicate the short term response of the system to this perturbation will be warming at the surface, concentrated at high latitudes, and cooling in the stratosphere.
• Observations and complex computer models agree with the first order predictions
• Chaos doesn't enter into it in the way that many people suggest. Climate prediction is different than weather prediction. Weather prediction out beyond a month is probably impossible, and even if it turns out to be possible, two months isn't. Climate is the average properties of weather. When I say that Christmas in Chicago is going to be colder than the fourth of July in 2304, I am making a 300 year climate prediction, and a perfectly reasonable one.
• The longer and more intense the perturbation, the larger the likelhood that our models (both computer models and simple conceptual models) will fail, due to lack of inclusion of normally slowly-changing phenomena taht are more likely to be in play with larger perturbations. In this case, the models will fail in the direction of understating, rather than overstating the consequences.