http://www.news.wisc.edu/thisweek/view.msql?id=3834
“A massive iceberg, perhaps the largest on record, has broken free from the Antarctic’s Ross Ice Shelf.”
I think this is more evidence of global warming. The polar caps are breaking up.
And your question is…?
TT
“It is better to know some of the questions than all of the answers.”
–James Thurber
No question. I am trying to start a debate about global warming.
Maybe it has nothing to do with global warming. Maybe it has more to do with the centripedal force on the iceberg (i’m waiting for a physicist to find the problem with that one) or seismic activity.
I am in no position to debate the evidence (or lack thereof) of global warming – but I do have a question for those that buy it.
Is it not the case that the Earth has been subject to glaciation many times in its history? That the cause for many of the mass extinctions of life through the planet’s history has been what amounts to global cooling?
In light of this, I guess I find it difficult to understand what the concern is with respect to global warming. We have been much colder, and gotten warmer, before, with any internal combustion engines in the picture.
True? Or am I hopelessly confused?
- Rick
combining global warming with the onset of the next ice age is like taking a handful of uppers and a handful of downers.
Regardless of what has happened in the past, the goal we should be trying to eachive is to keep the current temperature stable. If an ice age is coming, we should fight to raise the temperature to counterbalance the decreasing temperature. There is no need to accept what nature has in store, especially since it could cause massive extinctions, and our warming may preserve the planet as we know it.
That being said, it seems a bit beside the point. The average temperature has been increasing since we have been keeping track. We don’t need to worry about getting too cold, but rather getting too warm. Therefore, we need to worry about global warming.
Say, WHEN is it they’re launching that rebuilt replica of the Titanic, again?
Lets just lassoo the thing,haul it to the persian gulf and sell it for $1.50 a gallon.
Actually, the latest theory I’ve heard is that global warming may, ironically, trigger the next ice age.
What keep the glaciers at bay, presently, are the circular ocean currents (such as the Gulf Stream), which bring warm waters from southern climes to the northern oceans. Without the Gulf Stream, Europe and much of North America would be encased in ice right now.
The newest theory (and I picked this up from Discover Magazine, and also in a documentary on TV a couple of weeks ago) is that global warming will at first cause polar ice to melt (as described in the OP). This includes the ice shelves of Greenland, in the North Atlantic. The cold melt water and ice pouring into the North Atlantic from the Greenland ice shelf will in turn cause the Gulf Stream to shut down. When the Gulf Stream shuts down, the warming trend reverses itself, the cold sets in, the snow starts falling, and the glaciers advance.
Both the article and the TV special said that this scenario was supported by computer models, and both said it could happen **very **quickly. (I can’t remember the exact time range, but it seems like it could all happen within a 50 year window.)
How accurate are the computer models? Who knows?
Is the planet warming? Clearly. The ice caps are shrinking on both poles. The last three years in the US have been the warmest on record, with each year warmer than the last.
Are we humans causing the warming, and can we do anything about it? That’s a dicier issue. As Bricker noted, we have gone through several intermittent periods of glaciation and warming in the recent past (geologically speaking). Are the current events being caused by the Greenhouse Effect, or is it just part of a larger climatic shift over which we humans have no influence or control? I dunno.
My take on it is that if there’s even a 5% chance that we are causing the problem, then we need to act to try to correct it. If we can stop the process and fail to do so, the result may be disastrous.
150 years of record (temp.) keeping is not enough to adopt a fatalistic world view. Not to mention that the people of europe were convinced that another ice age was coming back in the 1300’s (700 years is nothing in geological time). As recently as the late 1970’s people thought there was another ice age just around the corner (based on a very cold and snowy winter).
We are currently in the midst of an interstital period and nobody knows when it will end.
Sometimes you feel like a coconut, sometime you feel like a yak.
I would not venture a guess as to whether we are really, really suffering from global warming created by humans.
There are generally four consequences that are speculated to be the result of global warming (if it is occurring).
If the global climate heats up enough, the land-borne glaciers and ice-caps of Antarctica, Greenland, Alaska, and a few smaller spots could begin to melt, raising sea level significantly. A fairly small rise could drown substantial regions that are currently very heavily populated: NYC, Florida, much of Louisiana, the entire nations of the Netherlands and Bangladesh, etc. That is a lot of people to relocate.
Flooding those countries would add immense pollution to the oceans as underground (or immovable above-ground) storage facilities and chemical fertilizers leached into the ocean. (Yes, we would pump out the tanks we knew of–that would still leave many smaller, unmarked tanks and does not address the fertilizer issue.)
Add the Arctic polar ice cap (which would not add substantially to the rise in sea level since its ice already sits in water) to the melted water and you can seriously dilute the salinity of the oceans with an undetermined ecological effect.
And, finally, the issue that we may already be dealing with: catastrophic changes in weather patterns. This is not limited to having a one or two dozen hurricanes inflicting Camille- or Andrew-like damage each century instead of three or four individual storms of that size. (It is possible that those are cyclic or that their destruction is more closely related to larger developed populations, although there is evidence that stronger storms are the result of warming oceans.) The real issue is that we do not know how the actual weather patterns will be affected over the long term. Are the successive droughts of the U.S. Southeast over the last ten years a harbinger of things to come? Will the Mississippi-Missouri-Ohio-Tennessee basin become a soggy mud plain suited only to rice? Is the same thing happening to southern France and Italy? Was it a shift in weather patterns that gave the Sahara the opening it needed to make 1/5 of Africa non-arable? (Once a desert is established, there are no models for how it can be reclaimed.)
I am making no claims because all the evidence I have seen is really inconclusive. (The strongest theories, in my opinion, are those linking more frequent, stronger hurricanes to oceanic warming. They are still not conclusive.)
However, in regards to Bricker’s question, those are the concerns.
Tom~
spoke- wrote:
I heard that theory too, on The Discovery Channel.
Thing is, the show that mentioned that theory then went on to present “evidence” for this new impending global-warming-induced ice age by saying that we’ve had record low temperatures during recent winters.
This kinda cheesed me. If we have high temperatures, this is evidence for global warming. If we have low temperatures, this is evidence for global warming. Is there any kind of weather we could have that wouldn’t be evidence of global warming?
tracer-
Don’t remember anything in the show about record low temperatures. They did talk about recent heavy snowfalls, which is a different thing.
I agree that they threw in some “sky-is-falling” filler that didn’t really advance their thesis, though.
Nevertheless, the points they made about a large infusion of cold water shutting down the Gulf Stream made pretty good sense on an intuitive level. I suppose time will tell.
–As useless as a one-legged man at an ass-kicking.
Global warming is happening. The question lies in how much responsbility lies with us, as humans. Whether this will stall or hasten the next ice age is yet to be determined. But Avumede’s suggestion that we proactively change the weather patterns is a little premature. Weather is still to complex to predict more than 10 or possibly 14 days out. To think that we could prevent a mass extinction might be a bit naive.
-Dave
“Violence is the last refuge of the ignorant.”
-I. Asimov
Heres my take on the global warming issue. Word on the street (street being the New York Times) is that the amount of CO2 (the primary cause of the greenhouse effect) that has been put into the atmosphere by humans in the last 100 years is about one tenth of one percent of the total amount during that time period. The most likely reason for the recent warming trend that everyone seems to be commenting on, is that the climate goes through cycles all the time. We are nowhere near understanding exactly how the climate works and our geologically puny weather records do little good. Until we have been around alot longer and/or have evidence that we are pumpin out significant CO2 into the atmosphere, we should not be overly concerned with global warming. However, pollution is much more than CO2, and should be dealt with very serioulsy, but that is another matter
"Never argue with an idiot. They drag you down to their level and beat you with experience
Hey everyone,
A bunch of the points and questions raised in this thread were covered in the GQ thread [Ice"]http://boards.straightdope.com/ubb/Forum3/HTML/005084.html]Ice]( [url="http://boards.straightdope.com/ubb/Forum3/HTML/005084.html) Ages and Us a little while back. Nutshell summary: yes, there’s some pretty good evidence that humans are contributing to (not causing) the recent warming trend; no, we can’t say for sure yet whether the current ice age is really coming to an end within the next few centuries.
To touch on some comments in this thread:
Bricker - Yes, the Earth has been both much warmer and much colder at various points in Earth history, so the current warming trend (and the anthropogenic contribution thereto) is not a big deal as far as Mother Nature is concerned. But since the anthropogenic release of greenhouse gases is associated with other pollution problems as well, I personally think it would be a good idea to cut back on any “offending” practices anyway. (Of course, this view would also be held by anyone with beachfront property. 
)
spoke- - The Gulf Stream is part of the global ocean circulation system, sometimes popularly referred to as the “ocean conveyor belt.” (There’s a nice readable description of this in a January 1990 Scientific American article, “What Drives Glacial Cycles?” by Wally Broecker and George Denton.) The ideas for what would happen to the climate if the oceans’ thermohaline circulation were shut down come from data reflecting climatic changes during the last few glacial-interglacial cycles. Briefly, when the ocean conveyor is weakened or brought to a halt, heat is no longer transported as efficiently from the tropics to higher latitudes, so the higher latitudes get colder. From the present data, it appears that the transition to colder conditions can happen within a decade or so. That doesn’t mean that you’d turn around and have a glacier in your yard, though, because it would take considerably longer for the snow to build up into a layer of ice of appreciable thickness.
As for computer models of climate - they do the best job that they can, given our current level of knowledge and computing power. Which is to say that none of them are perfect. There is actually quite a bit we don’t yet understand about how various climatic processes and feedbacks interact with one another, and on what time scales - that naturally affects our ability to make long term forecasts.
tracer - “Global warming” is often misunderstood (and incorrectly portrayed by the media) as meaning that the entire world will warm up evenly. Yes, the global mean temperature will increase, and the difference between daytime maximum and nighttime minimum temperatures will decrease. However, the effects of global warming will manifest themselves as changes in regional weather patterns, leaving open the possibility that some regions will be cooler and wetter rather than warmer and drier.
tomndebb raises the key points in the debate over global warming. I would just add that since a weakening of thermohaline circulation would mean that heat is not transported out of the tropics, there would be ample energy available in the surface ocean to drive large hurricanes or the theoretical monster “hypercanes.” So there’s pretty good reason to think that an increase in powerful storm activity, combined with a huge vulnerable coastal population, is going to lead to some of the largest natural disasters the U.S. has yet faced.
One last thing, concerning Avumede’s concern over possible mass extinction events… while I’m in favor of not deliberately wiping out species through human greed or carelessness, extinctions are a fact of life (so to speak) on this planet. If there are species lost during the coming climatic changes, I think there’s very little we can do to prevent them from happening; nor am I convinced we should try.
Rats! Here’s that link again:
There are several related issues here:
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Are humans causing global warming?
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If so, how much additional rise is attributable to humans?
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How much damage both ecologically and financially will this cause?
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How much will it cost us to avoid it, both in money and human terms?
None of these questions are easy to answer. So far, most of the warming trends we’ve seen are tiny, and largely consist of warmer nighttime temperatures. This may not be a bad thing for the globe. There is an awful lot of real-estate that would open up if the green belt moved 200 miles North. Whether this would be offset by damage in coastal areas is unclear.
The cost of the Kyoto accords is staggering. This has an impact not just on our standard of living, but our health. It may just be possible that more people will die from prevention of global warming than would die from it. We don’t have enough data to know.
For example: The eradication of DDT has caused malaria deaths to skyrocket. The elimination of CFC’s has raised the cost of refrigeration, which has directly led to an increase of deaths from malnutrition, food poisoning, and stomach cancer in the 3rd world.
The attitude that “we don’t know how much damage their is, so let’s be safe and pass a bunch of laws” misses the point that damage will occur EITHER WAY. The key is to take the path that causes the least amount.
In the mean time, where is this ice burg going? Will it melt before it hits a continent? Or will it get get stuck on another part of the ice shelf and freeze there?
Are you driving with your eyes open or are you using The Force? - A. Foley