General Question

amazon's avatar

What are the main causes of global warming?

Asked by amazon (44points) January 18th, 2008

Is global warming mostly the result of vehicles, airplanes, power plants, forest fires, volcanoes? Does anyone have a good pie chart that breaks down all of the causes by percent?

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21 Answers

felipelavinz's avatar

Not a pie chart, but an article that apparently deals exactly with what you’re asking: Causes of Global Warming

Some of the factors: power plants, cars, airplanes, buildings…

SquirrelEStuff's avatar

Is it true that cows are worse for global warming than cars?

jdvanderk's avatar

@chris, not true
Cows produce methane, and cars produce carbon dioxide (among other things)
in general, on a per mass basis, methane is a more potent greenhouse gas (more forcing per mass).

However, pretty sure that the sheer amount of car exhaust is enough to overcome this. (and the link below shows this).

@amazon As far as percentages, check out this from the IPCC, showing components of radiative forcing compared quantitatively in W/m^2

segdeha's avatar

Methane causes more warming than CO2, but CO2 stays in the atmosphere longer so it’s more of a problem long-term. That said, there are concerns that thawing of the Siberian tundra will release vast amounts of methane into the air, causing a spike in global temperature that could set of chain reactions of ice sheets melting, which would cause less sunlight to be reflected, which would cause more warming, etc.

kelly's avatar

read or listen to Michael Crichton’s “State of Fear” for some thought evoking concepts on global warming. True it’s imbedded in an action novel, but some of the other reasons are explored.

Michael's avatar

@kelly, yes and for more about amusement parks with dinosaurs, read Crichton’s Jurassic park. Just as authoritative.

hossman's avatar

Michael, perhaps you should check out the footnotes in Jurassic Park to the credible scientific studies used as the research basis for the novel. You are confusing how it was said (with a novel around the research) with what was said (credible scientific research).

You may disagree with the conclusions Mr. Crichton reaches, but kelly clearly is referring to the research footnoted in the novel, not the novel itself, when he clearly states “thought evoking concepts” are “imbedded in an action novel.”

Thus, if you wish to criticize the authority referred to by kelly, you need to criticize the research, not Mr. Crichton’s work of fiction or kelly.

hossman's avatar

@felipelavinz: in my opinion, and that of some studies I have seen, the link you gave gives short shrift to the impact of water vapor as a greenhouse gas, by suggesting the water vapor increase is, in effect, a side effect of the increased presence of other greenhouse gases. This statement in the link does not include the increased presence of water vapor that IS attributable directly to human conduct. Widespread irrigation, the damming of waterways to create lakes for recreation, water supplies and hydroelectric power, maintenance of water reservoirs for human water consumption, swimming pools, lawn watering, and replacing original environments with lawns and gardens requiring far greater water use than the original environment have increased the presence of water vapor in the atmosphere. Just think of all of the water vapor resulting from widespread lawns, gardens and agricultural fields replacing natural, arid environments in the western U.S.

One of the assumptions made regarding global warming that strikes me as logically weak is the assumption, frequently implied rather than express, that global warming (I’m not going to discuss now, for purposes of brevity, the questions of whether global warming exists and is a problem), without prompt human intervention, is an irreversible trend.

I don’t have any science to support the following, it is merely my own application of logic to some known facts, and there may be some big holes in this I don’t see at the moment. Thus, this is merely my own musing.

Certainly we all can agree that as a matter of the geologic record, the earth has been in ice ages, some of them very severe. I don’t think it is unreasonable to infer that as the glaciers that covered most of North America, Europe and Asia thawed and retreated, massive amounts of water would have been dumped into waterways, eventually causing ocean levels to rise. At the same time, there must have been a huge increase in the presence of water vapor, a significant greenhouse gas, from the larger volumes of water exposed to evaporation. Further, large amounts of methane and other greenhouse gases would have been released as permafrost and rotting vegetation under the ice was exposed. I do not know, but suspect as a logical inference, that the contributions to greenhouse gases from such an immense global thaw must surpass the current levels of human-caused greenhouse gases.

Logically, then, you would think the worldwide increase in greenhouse gases, when combined with global temperatures already increasing from other causes, would have created a synergistic effect, and global warming (which certainly was a good thing, coming out of a great Ice Age) would have continued to spiral upward uncontrollably.

Yet we know this didn’t happen, and the global warming eventually ceased, and although it changed the prior environmental conditions (for the better, if you’re huddled in a cave gnawing frozen mastodon) the global warming did not, as far as we know, permanently damage the global environment. Without any human intervention.

If the sort of irreversible upward warming trend, assumed by those asserting a global warming crisis, did exist, why has it not occurred before, if my logic above is correct? Is there some correcting mechanism we might not be discussing, or that has not been identified? Is all of this inherently cyclical, and what goes up will come down?

I suppose an argument could be made that the portion of greenhouse gases caused by humans, in addition to the natural causes, would be the proverbial camel’s straw. Is there some sort of documentation comparing human-caused factors to prior worldwide ice age thaw? I have seen a number of accounts that the eruption of Krakatoa did more damage to the global environment than our current pollution, if that is true, why didn’t we have irreversible warming (absent intentional human intervention) at that time?

Michael's avatar

Hossman, sure, sure. It’s all in the footnotes. Remind me to check the back of Rising Sun for an authoritative account of American-Japanese relations.

segdeha's avatar

@hossman, I think you’re onto something. Global temperature does go up and down in cycles so there must some corrective process that kicks in at some point. I guess the thing for me is that humans may be triggering the corrective mechanism before its time.

Maybe that’s no big deal, but it would likely (just as other spikes in the cycle have done) trigger mass extinctions as well as the displacement and death of possibly millions of humans. Its one thing if the earth does this on its own. If it’s something we’re inducing, I think we have a responsibility not to make it happen if we can help it.

hossman's avatar

Michael, have you seen the book? Have you seen the research? I don’t recall Rising Sun or Jurassic Park containing an appendix of supporting research, so you’re comparing apples and oranges. If you’re not going to offer some academic critique of the research referred to by kelly, then I fail to see that your posts offer anything but sarcasm and insult. Or are you one of the sheep that replaces knowledge with attitude? Again, you post with no intelligent criticism. Sassy is not thought.

@segdeha: it has just occurred to me that the “crisis” description of our world in the throes of a global warming is practically identical to the description of the environment during the Jurassic Period (thanks to Michael for triggering that thought). That was a time of flourishing flora and fauna, despite high sea levels and high humidity, and the environment corrected itself with a cooling cycle without human intervention.

Regardless of whether global warming exists, over vast amounts of time, undoubtedly something will happen to cause a mass displacement of humans. Hey, we displace ourselves because of war, economic conditions, political concerns, etc. Look at the shift of African-Americans to the North in this country. It is much less clear that global warming would cause the death of millions. Even if we’re inducing global warming, our well-intentioned “correction” could potentially be disrupting some natural correcting mechanism of which we are unaware, or if we were actually about to start a cooling cycle, might disrupt that. I just think we are so ignorant of global weather processes we shouldn’t meddle, even with good intentions. Sometimes acting without all the information can be worse than not acting at all. The important thing is, I don’t think we can know what is best at this time. That’s not to say it can’t be a good thing to reduce pollution of all sorts, for reasons having nothing to do with global warming. It baffles me why we are focusing on global warming as the primary reason for pollution reduction, when many people simply aren’t going to get worked up about what is going to happen centuries from now. What about the rising incidence of asthma? There are many more much better reasons than global warming.

I am concerned that since so much of the “consensus” regarding global warming is dependent upon softer science, including computer modeling, all based on guesswork, rather than hard, reproducible science, that if a significant discovery was made disproving the “global warming crisis,” it might cause a public critical backlash against climactic sciences, anti-pollution efforts, environmentalism and science in general. It is never good to place all of your eggs in one basket by over-committing to a theory that may change over time. Much of the public already distrusts the interface between science and government policy. Spending millions on global warming policy, if it should result in the “consensus” either being wrong or not the consensus its promoters have promoted, could result in the next crisis being unfunded and unsupported. You can only cry wolf so many times, and given the “consensus” was global cooling only a couple of decades ago, environmental policy could end up losing a lot of popular support.

Dine's avatar

The main cause for global warming are people by 100%.

Michael's avatar

Hossman, come on. Give me some credit. It’s not like it’s easy to be this sassy. It takes hard work.

hossman's avatar

Okey, dokey, Michael.

Has anybody else started seeing articles about how global warming may cause years of cooling weather, or may lead to fewer and less severe storms, as opposed to the inevitable annual increases and horrible hurricanes they were predicting a few years ago?

Has the “consensus science” (for lack of a better term) changed, or is somebody preparing an exit strategy? I also see many more references to climate change rather than warming. Is there a change in the science, or is somebody hedging their bets?

segdeha's avatar

@hossman, Can you throw some links up for us? Then, more of us will have seen the articles… ;-)

hossman's avatar

I don’t have any at hand, I saw several in passing when I was headed elsewhere. If I can run across them again, I’ll link to them.

It seems to me that regardless of whether global warming is occurring or is a crisis, it is awfully convenient for any politicion to have an agenda focused on a problem that will happen far in the future, largely evades proof, scares a significant part of the populace, and is one of those issues that is hard to oppose, like saving baby harp seals. Even more importantly, it must be a problem, like global warming, that you can throw millions of dollars at, and if something happens, you are a hero, if nothing happens, you ask for more money.

In the private sector, it’s called guaranteed employment.

justin's avatar

@Hossman, ‘Global climate change’ is prefered to ‘global warming’ because the science of how human activities are changing the chemical makeup of the atmosphere is measurable and ‘proveable’ much easier than the end effects of that change – ie ‘warming’. Also, the effects that are predicted are overall warming of the earth by several degrees on average, while the real dangers and adverse impacts are due to wider variations in temperatures and weather extremes – more floods and droughts, more heat spells and blizzards. Thus ‘global warming’ is not as accurate an account of what is being measured nor what the anticipated adverse impacts are.

While there are cooling effects as well as warming effects of changing the chemistry of the atmosphere, it is cause for concern precisely because it is so complex. The idea of the earth as an ecological or biological system, with self-correcting measures is a plausible one, but so is the chance that at some point we push the system beyond the point at which it can ‘easily’ correct. Even the chance that we will drastically change climate, or melt the polar ice caps, or cause the ocean current to shut down will drastically effect the systems that feed us: the fish we eat, the water that feeds our irrigation, etc. Large famine and migration, diseases, civil strife, etc. are plausible concerns. Yes this could also happen ‘naturally’ or may be repeating previous ‘natural’ cycles. That doesn’t mean it shouldn’t be considered catastrophic. If it is our doing or even if it is not, it is likely much cheaper to reduce our carbon consumption than adapt to and prepare for a wide range of uncertain future outcomes.

ironhiway's avatar

Published on Friday, January 30, 2004 by Thom Hartmann

How Global Warming May Cause the Next Ice Age

Ice age links
Not by Fire but by Ice

winblowzxp's avatar

Our climate is constantly changing. We should strive to be good stewards of the planet, not heroes. I don’t think that we can drive the planet into ‘overdriven warming’ so much that the planet won’t be able to heal itself. I think if it gets bad enough, then the planet will hit it with as powerful a force as it needs to. I doubt that if and when that happens, humans won’t be able to anything but sit and watch the show.

josie's avatar

The ebb and flow of the forces of nature.

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