So I have a quick question about "global warming"

[mdatspace]

Honestly, I'm of the opinion that global warming is more about politics than science.

For example, the accepted "scientific" mathematical models were not only completely wrong the last 15 years, during which time the Earth has actually cooled or stayed the same, and during which time Antarctic ice has actually grown and reached record levels, but they fail to model past weather which is known!

I believe they place far too much emphasis on CO2 in their models.

The reason why this smells political is because the bureaucracies involved are reluctant to publish any material which suggests that global warming is wrong.

Science doesn't toss out data because it doesn't fit the model...they change the model to fit the data.

There is also a lot of money involved with industrial carbon regulation and credits. Like most political things, follow the money. If this were purely science, you would follow the data...

Now, do I believe in climate change? Of course. The Earth used to have an atmosphere of hydrogen cyanide, and endless tropical oceans. As for right now, I believe we are still coming out of the last mini ice age (did you know that 1000 years ago, Greenland used to be green?). And when the Earth comes out of an ice age, it tends to gradually warm up.

The question is not whether or not the climate is changing, but whether or not humans are playing a large role in this change, and in a direction which would not naturally occur. Honestly, the idea that humans could affect something of this magnitude comes off as pretty striking arrogance.

But I'm open to being wrong. Just my opinion on the matter.

The reason why it bothers me is that it causes people to ignore very real, but less dramatic consequences of pollution. Mercury in seafood being one example.

"Honestly, I'm of the opinion that global warming is more about politics than science.

For example, the accepted "scientific" mathematical models were not only completely wrong the last 15 years, during which time the Earth has actually cooled or stayed the same, and during which time Antarctic ice has actually grown and reached record levels, but they fail to model past weather which is known!"

The 15 year gap is a commonly repeated myth with no basis in reality. Temperatures have still gone up.

http://climate.nasa.gov/key_indicators#globalTemp

"I believe they place far too much emphasis on CO2 in their models."

CO2 is a greenhouse gas, and it is perhaps the one we emit most. It is not hard to see why so much focus is on it.

"The reason why this smells political is because the bureaucracies involved are reluctant to publish any material which suggests that global warming is wrong."

This suggests a conspiracy, a cover-up. But what is the motive? What if there is no cover-up. What if the evidence against GW is negligible? 97 percent of scientists supposedly agree on this, so this could be reality.

"Now, do I believe in climate change? Of course. The Earth used to have an atmosphere of hydrogen cyanide, and endless tropical oceans. As for right now, I believe we are still coming out of the last mini ice age (did you know that 1000 years ago, Greenland used to be green?). And when the Earth comes out of an ice age, it tends to gradually warm up."

Greenland got warmer while the rest of the world got colder. While it tends to warm up after an ice age, the speed of today's warming is not associated with said warming.

"The question is not whether or not the climate is changing, but whether or not humans are playing a large role in this change, and in a direction which would not naturally occur. Honestly, the idea that humans could affect something of this magnitude comes off as pretty striking arrogance."

Multiple factors point to humans. We are enormous quantities of CO2 into the atmosphere. We dump 80 to 270 times the CO2 than volcanoes into the atmosphere. It is scarcely arrogance to say we are associated.

[K^2]

All people who claim "that stuff", or only some of them? Can you please expand?

There are, of course, plenty of competent people in climate and atmospheric sciences. They have their share of nutjobs, too, and lately, it's been popular to make some of the more exagerrated and less reliable claims into sensationalist news.

All of it is best illustrated with some toy models. Lets pretend, for a moment, that Earth was a perfect sphere of constant albedo and had the uniform temperature across the surface. Things are obviously way more complicated, but it's a good picture to start with. Earth is roughly 200 times further from Sun's center than Sun's own surface, and Earth is going to receive solar radiation with cross-section area ÀR² and radiate in IR from its total surface area 4ÀR². In other words, it radiates energy from 160,000 times greater surface area than area of Sun's surface from which it receives radiation. Since radiation of heat goes like T⁴, Earth is roughly (160,000)^1/4 = 20 times cooler than the Sun. This is in the ball park. If you do all of the algebra correctly and take albedo into account properly, you end up with a temperature that's a bit low, leaving room for various atmospheric effects.

Now, spectrum of radiation we receive from the Sun and spectrum Earth radiates back into space have almost no overlap. See the graphic I posted on the last page. So we could envision, in our toy model, a shell around the Earth that is perfectly transparent to Sun's radiation, and completely opaque to Earth's. Since energy flux in has to be equal to energy flux out, the total IR radiation outside from this shell has to be equal to the Sun's total radiation going in. So this shell will now have the 1/20th of the Sun's surface temperature. However, it radiates out and in. So Earth now receives twice as much radiation and has to radiate twice as much. To double the radiation output, Earth's tmperature has to increase by a factor of 2^1//4, or by roughly 18.9%. Taking Sun's effecive photosphere temperature, that would make for over 50°C increase. That's a lot. And this is basis for a lot of fearmongering.

Things are quite a bit more complicated, however, because we don't just have one layer of dense, IR opaque material. We have an atmosphere. First, note that adding another IR opaque shell makes absolutely no difference. The outer shell must still radiate the same amount, and the inner shell(s) end up in thermal equilibrium with an outer one. So the temperature of each shell is 1/20th of Sun, and Earth is still the same 18.9% hotter. What's interesting here is that we can have as many shells as we like, spaced any way we like, and onlly the shell closest to the Earth is going to matter. So radiation and re-radiation in upper atmopshere is pretty much irrelevant. We also know that this 18.9% jump isn't just going to happen right next to the surface. It can't, because we have air currents carry heat between layers of atmosphere as well, so things are going to get more interesting. But lets look at something else.

Now, lets suppose that shells are not 100% opaque. Lets compare two simple models. In one we have just one shell that's 75% opaque, in another we have two shells at 50% each. Note that the total is still 75%. For a single shell, denote Earth's radiation as x and shell's radiation as y. We know that .25x + y = Sun's total. And Earth is going to recieve the total + y = x. So now Earth has to radiate 8/5 the energy of the original model, and that means temperature is increased by a factor (8/5)^1/4 or about 12.5%. For the two spheres, .25x + .5y + z = total is going out, total + y + .5z = x is what Earth receives, and x/2 + y = 2z is what outer shell receives. So we get x = (3/2) of total, which gives us temperature increase of 10.7%. So multiple layers of partially opaque shells are much better than a single shell.

There is one more thing I pointed out. Upper stratosphere has an inverted temperature distribution. Lets see if we can model some of that. The reason for that inverted layer is the UV radiation absorbed by upper stratosphere, which doesn't reach lower stratosphere. Since we are playing with toy models, lets say that 1/2 of the Sun's total output, which I'll now abbreviate as t, is going to be in UV that is absorbed by the outer shell. Again, that outer shell is opaque in IR. So Earth recieves x = t/2 + y, while the outer shell still has to radiate the total t = y to the space. So Earth ends up being only (3/2)^1/4 or 10.7% warmer in this model.

In other words, if we allow the UV-absorbing portion of the atmosphere to radiate that heat in IR, Earth ends up being somewhat cooler.

The overall system is far more complciated, of course. In these toy models I completely neglect the air currents carrying heat between the layers. And because there are changes in pressure, atmosphere can actually function as a heat pump. This is most severe in troposphere, and ends up being a dominant effect on the temperature down here. This is why I started out my previous post by pointing out that IR absorption beyond troposphere makes very little difference.

[thereaverofdarkness]

From a long-term perspective, the Earth doesn't have too much to worry about. If we continue consuming fossil fuels at the current rate until our oil wells start running dry, the CO2 buildup will reach a point in which a runaway greenhouse effect will be achieved, causing the polar ice caps to melt. The increase in temperature will eventually cover much of the earth in thick clouds of water vapor which will deflect sunlight coming in. This cloud cover will remain for quite some time as the heat already trapped within will slowly seep out, but eventually (perhaps hundreds of thousands of years later), the clouds will thin out as the Earth cools again. It may go into an ice age, and if it does, it will eventually thaw and become warm again. If there is still too much CO2, it will overheat again, and go through another cycle. This process prevents the Earth from heating too far. There would be many extinctions from this, but the Earth would remain covered in life, and new evolutionary paths would open up. Humans would most likely survive but may go extinct.

[Maxwell Comp]

Is there any form of climate modeling software that is (somewhat) easy to use and "all batteries included"? I know that climate modeling is incredibly complex and requires much more computing power than the average home user has, but a simplified planet should be model-able with a home computer. That model may not be able to model the effect of ocean currents or arctic melting. But, it would be nice to have a planet with atmosphere that we can experiment with.

As an amateur software programmer, I have considered trying to make a simple model, though honestly a project like that is well out of my league. I would need to quit work and devote several years before I could begin to make real progress.

[Idobox]

An interesting fact that is rarely pointed out:

The sun is brighter today than in the past (normal for main sequences stars), it was about 10% dimmer 1 billion years ago, and by the beginning of the carboniferous, it was about 5% dimmer. But still, temperatures were quite warm on average.

This is because CO2 concentration was much higher, and this CO2 was captured by the biomass and turned into fossil fuels. We burn massive amounts of the stuff, we burn oil as fast as we can extract it, and coal only slightly more slowly. We release about 20 billion tons of CO2 a year, growing fast. We're releasing in centuries what took half a billion year for the biosphere to capture and store underground.

I don't think it's arrogant to think that dumping 20 billion tons of anything in the atmosphere every year for at least a century (okay, we dumped less, but for longer) can affect stuff. We are able to destroy the ozone layer and cause acid rains, fish all the fishes in the ocean, dig mountains, dry seas, etc. it's not difficult to imagine we can screw up the biosphere because we do it all the time.

About your diagrams, the 'small peaks' you're talking about are on the maximum of Earth thermal radiation, where their variation has the most effect. Even without that, ground heat is lost a lot by conduction and convection, and a more opaque stratosphere means the troposphere will loose heat at a slower rate, slowing down the whole cooling.

[Guest]

An interesting fact that is rarely pointed out:

The sun is brighter today than in the past (normal for main sequences stars), it was about 10% dimmer 1 billion years ago, and by the beginning of the carboniferous, it was about 5% dimmer. But still, temperatures were quite warm on average.

This is because CO2 concentration was much higher, and this CO2 was captured by the biomass and turned into fossil fuels. We burn massive amounts of the stuff, we burn oil as fast as we can extract it, and coal only slightly more slowly. We release about 20 billion tons of CO2 a year, growing fast. We're releasing in centuries what took half a billion year for the biosphere to capture and store underground.

I don't think it's arrogant to think that dumping 20 billion tons of anything in the atmosphere every year for at least a century (okay, we dumped less, but for longer) can affect stuff. We are able to destroy the ozone layer and cause acid rains, fish all the fishes in the ocean, dig mountains, dry seas, etc. it's not difficult to imagine we can screw up the biosphere because we do it all the time.

About your diagrams, the 'small peaks' you're talking about are on the maximum of Earth thermal radiation, where their variation has the most effect. Even without that, ground heat is lost a lot by conduction and convection, and a more opaque stratosphere means the troposphere will loose heat at a slower rate, slowing down the whole cooling.

We have not destroyed the ozone layer. I can still buy fresh Alaskan salmon at my local Walmart, along with pollock, shrimp, crab, and many other fresh water fish. The last time I was outside when it was raining, I did not melt, which some of my colleagues found disappointing. While there are many things I would like to see us do better as a whole as far as taking care of the environment, one also has to keep in mind that making policy based on fear can be just as bad or worse than the actual perceived problems.

[K^2]

An interesting fact that is rarely pointed out:

The sun is brighter today than in the past (normal for main sequences stars), it was about 10% dimmer 1 billion years ago, and by the beginning of the carboniferous, it was about 5% dimmer. But still, temperatures were quite warm on average.

This is because CO2 concentration was much higher

The reason it's not often pointed out is because every time it's brought up in intelligent debate, the other side immediately reminds the speaker that geothermal output of our planet was significantly higher then, and we were loosing geothermal at a faster rate than we are gaining in Sun's output. Decrease in geothermal output explains most of the temperature decline. By now, of course, geothermal output is almost insignificant on average.

and this CO2 was captured by the biomass and turned into fossil fuels. We burn massive amounts of the stuff, we burn oil as fast as we can extract it, and coal only slightly more slowly. We release about 20 billion tons of CO2 a year, growing fast.

Which is still only about a tenth of the rate at which carbon from atmosphere is bound by the biomass. That's something to keep in mind for perspective.

About your diagrams, the 'small peaks' you're talking about are on the maximum of Earth thermal radiation, where their variation has the most effect. Even without that, ground heat is lost a lot by conduction and convection, and a more opaque stratosphere means the troposphere will loose heat at a slower rate, slowing down the whole cooling.

Which is why cloud layer has a stronger effect, since it can dramatically increase absorption in mid to upper troposphere.

And yes, CO2 absorbs near peak of our IR output. Even in lower stratosphere, however, absorption specturm is completely saturated with H2O, leaving only a small window. And we are talking here about affecting some fraction of that. H2O is by far the dominant effect in greenhouse effect we currently experience, and the overal atmospheric effect is still under 30°C. Of that, only fraction is greenhouse in IR. Of that, you have a small window where it's not saturated, and of that you'll be able to affect a small fraction with CO2. Saying CO2 can contribute to a degree or two increase would be generous.

Besides, like you yourself pointed out, all the fossil fuels we burn used to be CO2 in atmosphere. So if we have to picture an absolute worst case scenario, we don't have to go far. And guess what, there was no runaway effect then, either. Ecosystem can cope with these CO2 concentrations as a matter of empirical fact. It already did. It can kill any number of modern species, sure, but again, Earth has recovered from worse. Several times. Humans can survive even that drastic of a climate change, along with enough of our food crops for us not to starve. (Don't forget that we can modify our crops if necessary.) So we'll have food and habitable environment even if somehow we manage to make Earth into what it was a billion years ago. In fact, direct CO2 poisoning is the only thing we have to worry about with the CO2 output, and we are nowhere near capability of getting to that point.

[drakesdoom]

-snip-

I interpret this to mean that I can complete my VV24 24.0L Diesel Dues and a half drag truck without worrying about changing the weather.

[kahlzun]

The way I tend to look at it is, we have an example of runaway greenhouse effect (Venus).

Obviously, our atmosphere is very different to Venus's, but the principles work the same.

Knowing that at least some of the gases on Venus are greenhouse, it then becomes an academic matter as to how much is required for an increase.

It is inarguable that greenhouse gases do not exist.

[PakledHostage]

I don't think it's arrogant to think that dumping 20 billion tons of anything in the atmosphere every year for at least a century (okay, we dumped less, but for longer) can affect stuff.

A lot of the time, the idea that it is "arrogant" to believe that humanity could change the climate comes from religious teachings. Unfortunately (or fortunately, depending on how you look at it), going to church on Sundays and watching Fox news aren't much in the way of credentials in the climate change debate.

K^2's argument is a little better because it is at least based on scientific reasoning, but even it has serious flaws. He argues that climate models should account for factors such as energy balance, heat transfer, atmospheric temperature and density distributions, etc, yet nowhere does he provide evidence that they don't. Instead, he presents models that he himself describes as "toy models" that contradict what the atmospheric scientists (some of whom, even he admits, are competent) are predicting in their peer reviewed research, and expects us to draw some conclusions from there about the flaws in climate science.

Rational people who believe the strong scientific evidence for climate change know that it does not result in the end of all life on earth. And that it does not necessarily result in economic catastrophe. Money spent developing alternative energy solutions pumps the economy and ensures that we will have options when the oil and coal eventually do run out. It also helps protect a very valuable resource: biodiversity. It isn’t wasted. It requires scientists, engineers and manufacturing jobs. It may ultimately result in a shift in the balance of political power away from the oil and coal industries, but life will go on.

[vetrox]

So far a rational discussion. I'm still reading through and alot is fasinating (even if i do have to go diggin around the internet (not the best place i know) for info)

Rational people who believe the strong scientific evidence for climate change know that it does not result in the end of all life on earth. And that it does not necessarily result in economic catastrophe.

Do you have a source for this? book or internet. Not that exact quote but some source that shows all life wont end as the media would have me think. I'm not doubting you but it would save me diggin around as I have given myself some serious headaches from staring at a white screen all day for the last few days. (brightness is as low as possible on this monitor!)

[K^2]

The reason I'm going with toy models is because I can run through all the algebra in a post. Anything more complicated would require heavy numerical integration. I do have resources to run something significantly more sophisticated. I do not have resources to run a simulation that realistically takes into account global temperature distributions and weather. But then again, nobody else has these resources either, so everything we have to go on comes from models that make some very restrictive assumptions.

But if you like, I can run some simulations of heat exchange in atmosphere that take into account altitude density and temperature variations and show that they give you the same results. I'd only be able to give you the model and the output, however, which would require you to take my word that I ran everything in between correctly.

[Sternface]

A lot of the time, the idea that it is "arrogant" to believe that humanity could change the climate comes from religious teachings. Unfortunately (or fortunately, depending on how you look at it), going to church on Sundays and watching Fox news aren't much in the way of credentials in the climate change debate.

K^2's argument is a little better because it is at least based on scientific reasoning, but even it has serious flaws. He argues that climate models should account for factors such as energy balance, heat transfer, atmospheric temperature and density distributions, etc, yet nowhere does he provide evidence that they don't. Instead, he presents models that he himself describes as "toy models" that contradict what the atmospheric scientists (some of whom, even he admits, are competent) are predicting in their peer reviewed research, and expects us to draw some conclusions from there about the flaws in climate science.

Rational people who believe the strong scientific evidence for climate change know that it does not result in the end of all life on earth. And that it does not necessarily result in economic catastrophe. Money spent developing alternative energy solutions pumps the economy and ensures that we will have options when the oil and coal eventually do run out. It also helps protect a very valuable resource: biodiversity. It isn’t wasted. It requires scientists, engineers and manufacturing jobs. It may ultimately result in a shift in the balance of political power away from the oil and coal industries, but life will go on.

I can assure you that I am neither religious, nor a devoted watcher of Fox news. Y̶o̶u̶ ̶a̶r̶e̶ ̶b̶a̶s̶i̶c̶a̶l̶l̶y̶ ̶s̶a̶y̶i̶n̶g̶ ̶t̶h̶a̶t̶ ̶i̶f̶ ̶o̶n̶e̶ ̶d̶i̶s̶a̶g̶r̶e̶e̶ ̶w̶i̶t̶h̶ ̶y̶o̶u̶r̶ ̶p̶o̶s̶i̶t̶i̶o̶n̶,̶ ̶o̶n̶e̶ ̶i̶s̶ ̶n̶o̶t̶ ̶r̶a̶t̶i̶o̶n̶a̶l̶.̶ And you do not distinguish between climate change, something which will occur in a dynamic environment as a matter of fact, with human-influenced global warming.

Logical fallacies do not speak much for debating credentials.

How does one explain how the global warming model, which is used as the basis of the theory, did not predict the increase in Antarctic ice, or the last 15 years of temperature stagnation?*

Have you looked at the evidence against global warming? It is far too soon to come to a conclusion either in favor, or against. We simply do not know yet.

*http://www.forbes.com/sites/jamestaylor/2013/09/26/as-its-global-warming-narrative-unravels-the-ipcc-is-in-damage-control-mode/

http://www.washingtonpost.com/blogs/capital-weather-gang/wp/2013/09/23/antarctic-sea-ice-hit-35-year-record-high-saturday/

http://www.forbes.com/sites/jamestaylor/2013/09/12/remember-all-those-breathy-predictions-about-an-ice-free-arctic-by-2015-nevermind/

Edited November 22, 2013 by Sternface

[PakledHostage]

Do you have a source for this? book or internet. Not that exact quote but some source that shows all life wont end as the media would have me think.

I don't know which media you are citing... I don't think I have ever read that anywhere in the mainstream media, and I am something of a news junky. In fact, I would be angry if I ever did read that in the mainstream media. It is just as irresponsible to fear monger about the end of all life on earth due to climate change as it is to dismiss climate change as merely "god's will". Both cost credibility.

And the evidence that, even in the worst case, life will persist in some form is the existence of extremophiles. Life already exists in some of the harshest environments imaginable here on earth and there's no reason to believe that it won't continue to do so for many hundreds of millions if not billions of years to come.

I can assure you that I am neither religious, nor a devoted watcher of Fox news. You are basically saying that if one disagree with your position, one is not rational.

No I didn't. I said "rational people who believe in climate change". There may well be rational people who believe in other things as well, and there are certainly some irrational people who believe in climate change.

Edited November 22, 2013 by PakledHostage

[ZetaX]

Would you please elaborate on that evidence against it¿ Because most of them I've seen on the web are of the creationist level of stupidity. It is a fact that a very huge majority of those that do the actual research agree on this topic, and it is not the general public that should judge this as it requires heck of research to even understand the more complex models, there is a reason one has experts on something, and it is outright ridiculous to have experts, but only believe them if they agree with you.

[Sternface]

No I didn't. I said "rational people who believe in climate change". There may well be rational people who believe in other things as well, and there are certainly some irrational people who believe in climate change.

Okay, I see what you meant. My mistake.

The way I see it is that if the model upon which the entire theory is based is flawed, perhaps the model and it's conclusions may be flawed as well.

I find it interesting how the bureaucracies involved with global warming are very selective in their evidence, and are very careful with their PR. To me, that screams politics, not science. Not to mention that fact that global-warming entities are all run by politicians.

It isn't as if there is nothing to gain either. There is a lot of money and power involved. Money and power tend to conflict with science, as history has showed time and time again.

None of this means global warming isn't real, and I am not saying it doesn't exist, only that I do not know. But I am quite cynical about it and the motives behind it.

Edited November 22, 2013 by Sternface

[Jim DiGriz]

And if you understand anything about how the "thermal blanket" effect works, you should realize that it's only relevant in the troposphere. "Greenhouse" is a terrible misnomer, since the actual greenhouse works completely differently. Upper troposphere is not particularly moist either, but still well within water vapor saturation.

You can go argue with what Pierrehumbert writes in this article and in the comments section here: http://www.realclimate.org/index.php/archives/2007/06/a-saturated-gassy-argument

He literally wrote the book on the subject.

They are balanced. They cannot be imbalanced. If they were imbalanced by a tiny fraction, we'd be cooked already.

They're imbalanced by a tiny enough fraction that we're warming up.

And again, CO2 concentrations in stratosphere are irrelevant, and these are the main contributions to the IR lines. Temperature there is inverted, so if anything, IR opacity can help cool the planet.

It cools the stratosphere, it does not cool the planet. Again, see comments by Pierrehumbert.

[Idobox]

Otis, we seriously damaged the ozone layer and caused massive acid rain (that damage crops, not your skin nor your car), but have reduced our emissions of harmful gases before it kiled us.

And yes, you can buy farmed salmon, but many species of commercial fish are almost completely gone. In France we import tuna from the Pacific, and there isn't any sardines left west of Canada, etc... We haven't completely broken the ecosystem, but we have come pretty darn close several times.

The reason it's not often pointed out is because every time it's brought up in intelligent debate, the other side immediately reminds the speaker that geothermal output of our planet was significantly higher then, and we were loosing geothermal at a faster rate than we are gaining in Sun's output. Decrease in geothermal output explains most of the temperature decline. By now, of course, geothermal output is almost insignificant on average.

I didn't know that, and checked.

http://www.sciencedirect.com/science/article/pii/S0012821X08007711#

1 billion years ago, it was roughly 50% more, and today it's about .03% of the total budget, so it was negligible then too.

Which is still only about a tenth of the rate at which carbon from atmosphere is bound by the biomass. That's something to keep in mind for perspective.

According to wikipedia (not the best source, but still a source), we released about 40billion tons of CO2 in 2011, about half of it by burning fossil fuels (not sure where the rest comes from, concrete?biomass?). The quantity of CO2 in the atmosphere has increased since the industrial revolution, and today increases by about 10 billion tons a year.

Add to that the absorption by the ocean itself (not the life in it, just the gas dissolving in water), that causes measurable acidification, and I seriously doubt biomass takes more carbon than we emit. Photosynthesis might, but since a significant amount of plant matter is burned or metabolized, you can't use that figure.

Also, nobody serious claims that carbon alone is enough to raise temperature by 5 or 10°C, but positive feedback loops can. Hotter weather means more humidity in the air, less ice, less permafrost and less methane clathrates. Methane released by intensive farming is an issue too, also of a much smaller scale.

Finally, nobody thinks global warming will destroy all life on the planet. The worst case scenario would be the oceanic circulation stopping, causing massive anoxia and release of toxic gases by anaerobic bacteries on the bottom of the ocean, which is thought to have cause one or two extinction events, and life survived that.

What people are worried about is extreme weather, and disruption of farming. Hotter weather means more and stronger storms and hurricanes. It also means the disappearance of the continental glaciers that regulates river flow, which would be devastating for agriculture in many areas. The Andes countries are the most concerned by that, especially Peru and Bolivia might see the first climatic refugees leave valleys in the next 10 to 20 years.

[vetrox]

I don't know which media you are citing... I don't think I have ever read that anywhere in the mainstream media, and I am something of a news junky. In fact, I would be angry if I ever did read that in the mainstream media.

Although not outright saying "the world will end" I have seen some news reports (not loads) saying that i could destroy life on earth.

Now as Im a muggle I didnt consider extremophiles. I was always under the impression (from only watching the news earlier in life) that global warming=human extinction. I.e if we dont cap our co2 emissions soon earth will not sustain life as soon as [insert arbitrary year here] but they never give a source for me to read the info!Anyway enough of the media and news. I wanted to try and keep them out of it (even if i was the one to bring it up).

Another generalisation I have (as do alot of others) is that global warming will cause wild storms, hurricane, snowstorms in africa (ok maybe i made that up) just like in "the day after tomorrow".

Could someone point me in the direction of a source (or just tell me) of how global warming would cause this. Like Idobox says, hotter weather = more humidity (if thats how it works) now my basic neanderthal knowledge leads me to believe this will cause us some bonus rain? (you see why alot of people are ignorant of the matter? Im not stupid but my knowledge on this matter is no more than joe publics...well, i have a little more knowledge now)

Edited November 22, 2013 by vetrox

[Jim DiGriz]

Again, that outer shell is opaque in IR.

The heating of the stratosphere is dominated by the UV absorption by ozone, which is why it has an inverted temperature with height. As you increase CO2 you affect its ability to radiate in the LW IR while not significantly affecting its ability to gain heat, hence it cools. That "not significantly affecting its ability to gain heat" is important for layers below it. For those layers, the stratosphere does not provide any significant thermal blanketing effect for outgoing IR radiation as we increase CO2 and we have to look at the relative balance between the increase in ability to absorb and radiate and the answer cannot be worked out in a toy model and must be integrated. The answer is that you get a greenhouse effect.

[Jim DiGriz]

We have not destroyed the ozone layer.

And we didn't because of the success of regulations banning CFCs worldwide.

[Guest]

And we didn't because of the success of regulations banning CFCs worldwide.

I agree that the banning of CFC'c was a success. But as far as us destroying the entire ozone layer with it planetwide, even on purpose if we tried, I have my doubts. I'm sure many of you can site scientific study after study claiming otherwise, I just have a hard time getting it through my thick skull. I have read and heard that the ozone hole over the south pole may very well be a natural phenomenon that we didn't have anything to do with. It reminds me of forest management in the Western U.S. Many people think that fire is bad, put out fire! But the fact is, fire is a natural part of the forest cycle. By not letting fires take their natural course, we actually end up causing worse fires due to the buildup of undergrowth. Also take into consideration the banning of DDT. If we would have went ahead and wiped out mosquitoes, we could have saved thousands or more from malaria. There are two sides to the coin. It's in my DNA to error on the side of caution and let Mother Nature iron out the problems. She's done a pretty good job so far.

All that said, I also take CO2 discussions and climate change with a grain of salt. Common sense tells me that climate patterns change due to many factors. When my local weatherman is able to predict the weather 5 to 7 days out with more than 50% accuracy, then I'll start to put more faith into what I am being told about human influence of the global climate picture. The law of unintended consequences is also very real. One has to take precautions that he doesn't shoot himself in the foot.

There is no doubt in my mind that you guys are WAY, WAY smarter and more dedicated in your studies than me. I'm just trying to interject a little caution and country boy common sense into the discussion. Keep up the great work!

Edited November 22, 2013 by Otis

[Idobox]

Now as Im a muggle I didnt consider extremophiles. I was always under the impression (from only watching the news earlier in life) that global warming=human extinction. I.e if we dont cap our co2 emissions soon earth will not sustain life as soon as [insert arbitrary year here] but they never give a source for me to read the info!Anyway enough of the media and news. I wanted to try and keep them out of it (even if i was the one to bring it up).

Another generalisation I have (as do alot of others) is that global warming will cause wild storms, hurricane, snowstorms in africa (ok maybe i made that up) just like in "the day after tomorrow".

Humans are pretty resistant to extinction because of technology, that being said, if climate change severely impacts crop yield and we can feed only a billion people, the transition will be pretty horrible. Forcing a billion or so people to move because of the rising sea level would be pretty terrible too.

Storms and hurricanes are, put simply, a consequence of the ocean cooling down. If the ocean gets warmer, and the air more humid, it will be more difficult for the ocean to cool down, ie, it will have to move more air and water around, and move it higher. Which means more powerful storms.

On top of that, the climate is a very complex system with lots of feedback loops that can go haywire. For example, at the same latitude, the climate in Europe is much wilder than on the east coast of North America because of the gulf stream. If the gulf stream slows down, a possible consequence of global warming, Europe would get colder. Another example is the polar vortex, which from what I understand, keeps cold air from going south. With the ice cap melting, this vortex is supposed to somehow weaken, letting more blizzards in Northern Europe and Canada, resulting in stronger temperature variations.

But as far as us destroying the entire ozone layer with it planetwide, even on purpose if we tried, I have my doubts. I'm sure many of you can site scientific study after study claiming otherwise, I just have a hard time getting it through my thick skull.

Ozone is unstable, and CFC are a source of free radicals that catalyse the reaction. Try putting some Iron oxide powder (rust) in peroxide, and you'll see you don't need a lot of pollutant to cause large effects.

Using DDT would have severely damaged the ecosystem, which would have reduced crop yield by killing the birds that eat insects. It is also toxic to humans. It is difficult to tell the balance of people saved vs people killed by forbidding DDT, but we now have pesticides that are very efficient while being less toxic. If DDT was never forbidden, we might not have them today.

There are many things mother Earth can't really process, at least not fast enough to compensate for 7 billion humans acting stupidly. You wouldn't pour toxic waste in your garden expecting nature to process it, or disperse plastic bags everywhere hoping for them to biodegrade or something.

And lastly, climate is a choatic systems, which means it's difficult to predict what is going to happen, but it is not very difficult to see what has happened already. And since the industrial revolution, a very short time for this kind of things, CO2 levels have soared, temperature is rising, glaciers are melting and species move to places that used to be too cold for them. Experts don't agree on the consequences of rising CO2 levels, but they pretty much all say it's going to change stuff, which is a bad thing when our food depends on climatic conditions.

[Kerbart]

It's important to distinguish global warming from what causes it.

Is it getting warmer? With practically every year breaking heat records and the last 10 years all being in the top 15 of what is on record (or something along the lines) I think it's pretty hard to deny that. A lot of people don't realize that history was written twice this year: vessels crossed on their own power, without an icebreaker escort, both the northwest passage (from Asia to the American east coast, north of Canada) and the northeast passage (from Asia to Europe, north or Russia). Those are long routes, and both were ice-free, making it hard to write it up to a fluke of local weather conditions (unless you consider the entire friggin' arctic circle one "local" area). That was a first for both. You don't need a bit of climate warming for that. You need a lot of climate warming for that.

The second question is what causes it. And that's important because depending on the cause Opinions, obviously, vary, and that's where the fun starts. To be honest, both camps are at a disadvantage. Those who claim human actions as a cause do have to deal with the fact that for years facts were "massaged" and that "correlation means causality" seemed to be the unscientific mantra for climate scientists for a long time as they had nothing else to go by.

But the "mankind has nothing to do with it" camp is not that much better off; for years they've been denying that the climate is warming up in the first place and proven wrong once makes it a lot harder to be taken serious the second time.

Proceed with caution? Both camps look at it like that. Should we take deep-cutting steps to reduce CO2 emissions while we're not even sure it will help? Then again, do we want to say 50 years from now as the world is ravaged by wars over water and food, "why didn't we take steps to prevent this 50 years ago? Because we were only 98% sure, instead of 100% sure?" (yes I'm biased)

The biggest mistake in any case is saying "there's no evidence, so we don't need to research it;" it's important enough at any rate so say "there's no convincing evidence either way, so we really need to research this". The one thing we can all agree on is that right now the climate is warming up, and closing your eyes for that and pretending it doesn't happen to the extend of putting that in law (like some US state governments do) is very unfortunate.

(...)Another generalisation I have (as do alot of others) is that global warming will cause wild storms, hurricane, snowstorms in africa (ok maybe i made that up) just like in "the day after tomorrow".

Could someone point me in the direction of a source (or just tell me) of how global warming would cause this.

Weather systems largely depend on energy flowing in (it gets warmer) and out (it gets colder). The sun is an obvious source of energy but not the only one. There are both in the ocean (gulfstream) and in the atmosphere (jetstream) large powerful global "conveyor belts" that push air and water around in a continuous loop. Global climate change can influence those systems and accelerate or stop them. To give you an idea, the winters at the US north-east coast are generally pretty cold with lots of snow. But at the same lattitude, in Europe (southern France and Spain/Italy/Greece) winters are mild and warm. Go a couple of hundred miles north and you have blistering cold winters on the American continent, while northwestern Europe (United Kingdom, Germany, the low countries) have mild winters with temperatures usually not going a lot below freezing level for a long time. Relatively warm water (coming all the way from the Caribean sea) that warms up the air above the Atlantic ocean causes that.

Stop the gulfstream, and NW Europe will be plunged in blistering cold winters, is the expectation -- and all climate models point to just that when temperature goes up. So there's an example of localized weather (in the winter) getting colder as a result of global warming.

If that sounds unlikely, keep in mind how messed up the weather in the USA is an "El Nino" year, when oceanic currents along the south american coast reverse direction; a good example of the influence oceanic currents have on weather thousands of miles away.

[Guest]

Yeah, after I made my post, I studied more about DDT. That was a bad example.