Alaskan glaciers and global warming

december, not all scientists believe in evolution either. You are never going to have complete unanimity. However, the fact that all the scientists that I know of who hold strong contrarian views on global warming all seem to have strong ties to libertarian or right wing think-tanks and/or Western Fuels Association, etc. suggest to me (along with other evidence such as the reports of the IPCC and the NAS) that nearly all scientists in the field who don’t have major personal biases do now agree with the general consensus on global warming. (Which is that the net warming we have seen in the 20th century is likely due mainly to human activity and that we will very likely to certainly see significant anthrogenic arming in the 21st century.) Hell, even some of the contrarians like Patrick Michaels (Prof at U.Va., Fellow at the Cato Institute, and with funding from Western Fuels Association) no longer dispute the fact that anthrogenic warming is a reality…Rather, Michaels now argues that it will be near the lower end of the IPCC estimates and that it will be “no big deal” (mainly because of where he believes most of the warming will occur).

A rough analogy would be if all the scientists who believed in anthrogenic global warming had strong ties to Greenpeace or the Socialist Party or some such things, while the rest of the scientific community didn’t believe in it. I doubt that such an imaginary situation in the reverse direction would prompt you to conclude that the scientific question was still largely undecided.

december, not all scientists believe in evolution either. You are never going to have complete unanimity. However, the fact that all the scientists that I know of who hold strong contrarian views on global warming all seem to have strong ties to libertarian or right wing think-tanks and/or Western Fuels Association, etc. suggest to me (along with other evidence such as the reports of the IPCC and the NAS) that nearly all scientists in the field who don’t have major personal biases do now agree with the general consensus on global warming. (Which is that the net warming we have seen in the 20th century is likely due mainly to human activity and that we will very likely to certainly see significant anthrogenic arming in the 21st century.) Hell, even some of the contrarians like Patrick Michaels (Prof at U.Va., Fellow at the Cato Institute, and with funding from Western Fuels Association) no longer dispute the fact that anthrogenic warming is a reality…Rather, Michaels now argues that it will be near the lower end of the IPCC estimates and that it will be “no big deal” (mainly because of where he believes most of the warming will occur).

A rough analogy would be if all the scientists who believed in anthrogenic global warming had strong ties to Greenpeace or the Socialist Party or some such things, while the rest of the scientific community didn’t believe in it. I doubt that such an imaginary situation in the reverse direction would prompt you to conclude that the scientific question was still largely undecided.

Increased levels of carbon dioxide will have significant ecological effects even if they (somehow) don’t cause global warming.

Earth’s atmosphere is relatively poor in carbon dioxide, and plants rely on the gas to provide carbon for growth and food synthesis. Grass in particular is highly evolved to use carbon dioxide efficiently. When the levels of carbon dioxide increase, the grasses will lose their edge over other plants, altering the ecological balance in possibly unpredictable ways.

On a very much lighter note, you might be amused by the comments allegedly made by a very young person on the subject of global warming. (Thanks to Why A Duck for finding this!) :cool:

Wouldn’t a massive volcanic eruption offset the global warming for a while? I thought I read somewhere that volcano eruptions spew enough particulate into the air to diffuse sunlight thus cooling the Earth. Wasn’t there a huge eruption back in the 90’s in the Phillippines that effected the Earth’s temp? Granted, hoping for a volcanic eruption to slow global warming is not the best course of action. Hoping for a big asteroid to kill us all is the best. :wink: But maybe the Earth has a way to offset the warming.

Volcanos sometimes spew large amounts of dust into the air, reducing the amount of sunlight that reaches the surface of the Earth and cooling temperatures.

Unfortunatly, they also sometimes spew large amounts of carbon dioxide into the air, presumably increasing greenhouse effects.

I’m not disputing that there may be serious consequences, just that humans would go extinct.

The Ryan: respectfully, I’m not sure you understand just how serious the consequences of a ten-degree global increase in temperature. It wouldn’t guarantee the extinction of the human race; it merely makes it extremely probable.

Drat. Add the words ‘would be’ at the end of the previous post’s first sentence.

That is an interesting point, TVAA; grass evolved and became widespread during the Tertiary period, which had lower carbon dioxide levels than the preceding Mesozoic; in fact carbon dioxide levels currently are very low compared to the level indicated by the fossil record for most of the period that life has existed on Earth.

So if C02 levels reverted to Mesozoic or Palaeozoic levels, life would no doubt adapt, and in fact thrive;

but we would probably lose all our cereal crops;
also the widespread flooding would cover the world to a depth of perhaps 80 metres, displacing populations from the most crowded and fertile areas, and expecting them to survive without bread or rice.

We cannot however do without global warming altogether; the Earth would be as inhospitable as the moon without the effects of greenhouse gases, and the long term trend is for atmospheric carbon to incorporate into sediments and decrease, which is a very strong candidate for the cause of the Quaternary ice ages.

We need to be able to regulate the CO2 level in the future, in order to prevent millions of years of ice cover for our planet; it may be that anthropogenic CO2 is all that is keeping the ice at bay…
in order for Earth to be maintained at a hospitable temperature
CO2 will need to be released in a controlled fashion, and after some tens of millions of years the gradually warming sun will take over and banish ice ages for ever.

After perhaps a hundred million years we might find that the warmer Sun makes it necessary to decrease CO2 to a very low level; before the sun turns into a red giant we will need to erect a sunshade.

Climate modification is a very complicated endeavour, but in order to live on Earth it will soon be necessary; with the lessons learnt here perhaps we can tackle the greater challengesof terraforming distant planets


SF worldbuilding at
http://www.orionsarm.com/main.html

Regardidng “Global Warming” : we are now in a natural cycle of warming (in the Northern Hemisphere). As others have pointed out, the last warm period was from ca 1000 AD-1300 AD. proof of this:
the Vikings settled in Greenland, and were able to grow barley and wheat there. The areas where they lived are now permafrost-no such crops can be grown there today. The Alpine and Alaskan glaciers are indeed melting back-as are the snow capson Mts. Kilimanjaro and kenya in Africa. These glaciers are remnants of the last cool periods…people forget that the Alpine Glaciers advanced into populated areas in the 1500’s.
So, man has had some effect on the climate…but much less than the natural cycles.

Minor problem: While carbon dioxide levels were much higher early in Earth’s history, the Sun was also noticably cooler than it is now. Without the higher greenhouse effect at the time, Earth would have been much cooler than it was, and the history of life would have turned out very differently.

Returning Earth to Paleozoic levels of carbon dioxide would produce the same greenhouse effect, but with a significantly more potent Sun – the effect wouldn’t be the same at all.

(There are of course other factors – the shape and position of the continents have a large effect on climate.)

Thank you, ralph124c, for your analysis. But, if you are going to reach conclusions on your own that are in conflict with those of the general consensus in the peer-reviewed scientific community, the least you could do is give us your credentials so we might judge how much weight to give to these conclusions. At the moment, I give none.

eburacum45: While it may be an interesting question how climate will naturally change and how it might need to be “regulated” by human intervention over the long-haul, what we are talking about happening now is man altering the climate at an unprecedented rate. The idea that anthropogenic CO2 is the only thing that is keeping the ice age at bay may be an interesting theory of yours, but again it is not an accepted theory in the scientific community.

I mean I am as much in favor of democracy and free expression of ideas as anyone but I think you have to recognize that some of these ideas expressed in this thread which are devoid of any real support in the peer-reviewed scientific community should not be treated on par with the actual accepted scientific body of knowledge.

Thank you for those chastening words, jshore I realise that this subject is too serious to be taken lightly;

I fully endorse the Kyoto Agreement as a short-term measure, and was only trying to stress the importance of long term climate control.

In looking beyond the near future I was trying to stress the need for a long term strategy;
by hoping for and believing in a better future we can tackle today’s problems without pessimism.

OK jshore, I’ve read through this thread, and it seems that most of your tactic consist of declaring the Gloabla Warming is pure and accepted, and that anyone who doubts GW is either a loon, a right-winger, or a scientist so poor that you get to compare them with Creationists. Thus any criticism of GW is purely from marginalized and extremist sources.

That is simple not true There is far more controversy than you woul dhave ius believe, or is Science now a fringe magazine?

From that article:

The “consensus” is not as tightly-knit as you would have us believe.

No, smiling bandit’s right - ironically, global warming could lead to global cooling. Here’s something of how it goes (some details may be wrong - I’m remembering from a Scientific American from oh, a year ago, which, depending on your view, may or may not be reliable):

Global warming melts ice locked in the caps (and in various other locations). This melted icewater contains no salt. Melted icewater enters the oceans, eventually decreasing salinity. Salinity, among other things, is one of the drivers of the massive “global conveyor belt” of warm/cool water movement the oceans contain. As the salinity decreases, this conveyor belt breaks down, meaning that warm water from the tropics is no longer moved to higher nothern/southern latitutes. Without the warm water to warm their shores, Britian and Europe (and presumably other locations) freeze. As they cool, glaciers descend - another ice age. This all seems plausible to me, but you’d need the word of a climatologist or oceanographer for better proof than my remembrances of a year-old article.

There’s also some speculation (according to the same SciAm article I read, oh, a year ago) that the newly formed glaciers could also lead to global warming - something about increasing the albedo and reflecting more sunlight into the atmosphere, warming it. Sadly, I’m a little fuzzy on these details. However, you see the cycle forming.

Either way, it looks like we’ll eventually be toast. But, then again, the planet’s never had a problem - it’s us that have the problem.

Snicks

Mr. M: The “consensus” is not as tightly-knit as you would have us believe.

I think what jshore is describing as the “consensus” is simply, as he said above, that “the net warming we have seen in the 20th century is likely due mainly to human activity and that we will very-likely-to-certainly see significant anthropogenic warming in the 21st century.”

This doesn’t preclude a lot of uncertainty about the models involved, nor does it contradict the caveats in the article you linked to, about probably needing another decade before we can be certain about anthropogenic global warming one way or the other. But it ties in fine with the conclusions at the end of your linked article:

In other words, it is generally agreed that (1) humans have been increasing atmospheric CO2; (2) if this anthropogenic increase continues, at some point, the increased CO2 will significantly warm the planet; (3) current models and results indicate that that point either was recently passed or will be passed shortly. Which, it seems to me, is exactly the “consensus” jshore was describing.

It’s one thing, and quite a good thing too, to point out that climate science is not as well understood as, say, basic mechanics, and thus a lot of the conclusions are necessarily somewhat tentative (which is something I think jshore, with all his careful “likely’s” and “mainly’s” and “probably’s”, understands as well as anybody else).

It’s quite another thing to attempt to argue “well, since the scientists aren’t confident about the results, other theories are just as good so we can afford to ignore this at the policy level and anyway it’s all a PR stunt to get grant funding.” That kind of simplistic, uninformed stance doesn’t really contribute anything to an intelligent debate, and I think it’s understandable that people who are better informed find it exasperating.

I dislike arguments from authority as much as anybody—and so, I believe, does jshore—but at some point, if there’s a significant imbalance between two sides of an issue in terms of how much their advocates know what they’re talking about, you’ve got to point that out.

Of course, it’s true that we won’t be absolutely certain of the effects of human technology on the climate until they occur. But by then, if the results are negative, it will be too late to stop them.

Which is precisely why I’m so annoyed by those puppets of industry that constantly claim “since we’re not completely certain that we’ll have a negative effect on the environment, we shouldn’t take precautions or restrict business”. If you think a gun might possibly be loaded, it’s only common sense not the pick it up, aim it at your head, and pull the trigger.

Did you notice that the article that you quoted (somewhat selectively) from is from May 1997? That is now over 6 years ago and is a few years before the issuing of the Third Assessment Report of the IPCC that says it is likely that most of the warming seen in the latter part of the 20th century is anthrogenic. If you want to see some more recent stuff, look at Editor-in-Chief Donald Kennedy’s editorial “An Unfortunate U-Turn on Carbon”, Vol 291, p. 2515 (2001) or “The Policy Drought on Climate Change,” Vol. 299, p. 309 (2003).

From the former editorial:

Note, I am not claiming that everything is known. There is still the word “likely” inserted into the attribution of most of the warming that has occurred in the latter part of the 20th century being due to man. And, there are considerable uncertainties in the magnitude of the effects as evidenced, for example , by the large range in the IPCC predicted warming for the next century of 2.5 to 10 degrees F. Clearly, whether it will be at the high or low end of this range is important and still unknown. (And, of course, there is still some chance that the warming will be outside of this range…either on the high or low end.)

Yes, we are making policy decisions here with imperfect scientific knowledge. But, since the dangers are quite large, most people who understand the science seem to believe that it is only prudent that we take steps (admittedly this is a policy question…not just a science question, although the science can inform it).

There has been a persistent attempt on the part of those who have a stake in not taking action to distort to science and exagerate the uncertainties. (Or sometimes, to say with more certainty than is warranted that they know exactly what will happen, at Patrick Michaels does, for example.) Examples of this have been repeated by some posters in this thread.

Here, by the way, are links to the Science editorials, although you may need to go through a free registration process at the site to access them:

http://www.sciencemag.org/cgi/content/summary/291/5513/2515
http://www.sciencemag.org/cgi/content/summary/299/5605/309

Snickers: You are right that there is an emerging concern about sudden climate change, especially about its being brought upon us by the forcings we are exerting on the climate system. And, you point to one example. My impression, however, is that this would not necessarily lead to a global cooling but to a very dramatic cooling in one region of the world (and, a region that we happen to care about quite a bit!). The possibility of such dramatic nonlinear responses of the climate system to the forcing we are putting into it is indeed a very serious concern, although one should hasten to add that the science on this aspect is still fairly young.

Another note added in preview: What Kimstu said!