Man-made Global Warming

[rushingwind]

I am probably opening a can of worms with this post, but... well, we'll see what happens.  

I once believed very firmly in man-caused global warming. I believed that we were forever ruining the environment and setting ourselves up for a "Day After Tomorrow" type catastrophe (Great movie, but it's dead wrong on so many fronts). It was all so clear to me. The reports all pointed to it, all the scientists agreed: Something was wrong, and we were causing it.

And then I started actually studying the environmental sciences, instead of relying on internet armchair/Wikipedia science. I began to look into the debate, and saw that almost all the major critics of man-made global warming were geoscientists and climatologists, the people who actually know what they're talking about. I read that the most popular reports that scare people about global warming, the info used in Al Gore's famous documentary (that I loved up until about two years ago), all that scary info was actually falsified.

I try to remain neutral in opinion about this, because I admit that just because I'm a student of the environmental sciences doesn't make me an expert. But my opinion has been slowly, but surely, shifting in the other direction. I find that much of the rhetoric I hear repeated about global warming is much like a lot of the nonsense repeated constantly about diet science: I.E., it's been said so many times that people just assume it's all true. That it's all "unquestionable." There will be DIRE consequences, you know?

One popular claim: The Earth is undergoing a rate of mass extinction at a rate faster than any other time in Earth history. This is just not so.  While we seem to be undergoing an extinction event, Earth has pulled out at least one mass extinction that makes stuff going on now look like child's play. It's called the Permian Mass Extinction, and it occurred at the end of the Paleozoic Era. 95% of all vertebrate and invertebrate life went extinct, both land and marine. You may have heard of an event at the beginning of the Paleozoic called the Cambrian Explosion. There were a few minor extinction events during the Paleozoic, but in general, both land and marine fauna were far more diversified and numerous than at any point since.

The leading theory about the Permian Mass Extinction has to do with a mantle hot zone erupting into present-day Siberia for... oh, about a thousand years straight. A mantle hot zone is basically a pipeline straight from deep within the Earth's mantle to the surface. The mantle, contrary to popular belief, is not molten. It's actually solid because its under such great pressure (the asthenosphere, which the Earth's crustal plates (lithosphere) moves around on is partially molten, and sits atop the mantle). In a mantle hot zone, the rock rises from deep in the mantle, and undergoes decompressive melting, which causes it to erupt on the surface. This event raised the global temperatures, which resulted in stagnating ocean currents, which killed nearly everything in the water except anaerobic bacteria and other small creatures capable of surviving in anoxic waters. Climate changed on a massive scale the world over, heating up incredibly. Earth very nearly wiped the slate clean of life 248 million years ago, all without human help.

For a modern day equivalent to that massive mantle hot zone, look to Yellowstone National Park. Which has been rising about an inch a year since 2006 as the magma chamber beneath it swells and mushrooms the Yellowstone plateau upwards. And there are a lot of Earthquakes there as the magma plume pushes on the land. Comforting, eh?

The idea that melting ice from the poles will create a Waterworld type environment is silly. First of all, polar ice is only a sometimes-occurrence in Earth's history. For most of the Mesozoic era, we had no polar ice. In the very early Mesozoic, when Pangaea was still together but starting to rift, all land was not under water. Even after Pangaea had properly broken up into a bunch of pieces, land still was not flooded by water. (Epieric seas, or shallow, inland seas, are an entirely different occurrence that has nothing to do with sea level). Before the Mesozoic, in the Paleozoic, Earth had a few episodes of glaciation alternating with no polar ice. Even further back in the Proterozoic (second half of the Precambrian), Earth wildly bounced between a "snowball/slushball Earth" and no polar ice.

The CO2 thing also makes me scratch my head, as if people think it's strange that there's an increasing amount of CO2 in the environment when Earth has a history of doing this sort of thing. At the tail end of the Mesozoic, there was twice the percentage of oxygen in the Earth's atmosphere than there is now, and Earth cut that in half all by itself, and did it fast enough that it coincided with another extinction event.

Is the increasing amount of CO2 bad? Yeah, for us. For mammals, certainly. Not for the Earth. Not for all life. If we're wiped out, the next creature capable of surviving will expand to fill our former roles. After the Permian Mass Extinction, reptiles owned the Earth. After the Mesozoic extinction, mammals inherited the Earth.

The Eyjafjallajökull volcanic eruption in 2010 released more CO2 into the atmosphere than humans have managed to do in the last 40 years put together. For days, flights were delayed or redirected, and ash fell. But now, has there been any massive change to the world environment because of that one eruption?

Don't misunderstand me. Pollution is a bad thing, because it's bad for us. It's bad for life. It's bad for biodiversity. Undoubtedly, our careless dumping of trash and crap into lakes and rivers causes problems for biodiversity. We can cause extinctions that way, and we undoubtedly have. I am anti-pollution because I am pro-biodiversity (and, you know, pro-human).

A footnote: Ice cores are only valuable for the last 500,000 years or so, which sounds like a long time.... but it's not. When you hear talk about India ramming into Asia at a "high rate of speed" to create the Himalayas, keep in mind that it moved a blazing 20cm a year. That's roughly the length of a tall cup. To try and conceptualize geologic time, imagine that India moved from the area of present day Antarctica to collide with Asia... by moving the length of a cup every year. That should put it into perspective that we have no way to really conceptualize how immense geologic time is (or universal time, for that matter, which is much longer). When we talk about dinosaurs, life before the dinosaurs.... We're basically talking all within the last 542 million years. Again, sounds like a lot... except it's only 16% of geologic time. There's at least another 4.1 billion years that went before the dawn of the Paleozoic and the Cambrian Explosion.

Check out this image:
http://www2.estrellamountain.edu/faculty/farabee/biobk/geotime_usgs.gif

Anything bigger than a small clump of bacteria lived within the last spin and a half of that wheel. "Fast" is a relative word when you start getting into spans of time like that.

If you read through all of that, you might think I'm here to argue that man-made global warming is all nonsense. However, like I said, I'm trying to remain neutral on the topic, and I want others' opinions. Does anyone know of any reputable, recent research done comparing paleoclimates with the modern climates? Good evidence not peppered with politics? I am not an authority on this topic, and what little I know just tells me that I really know nothing in the grand scope of things.  From what I little I do know, it seems like we're tiny drops in the bucket compared to Earth. If she wants to pull the plug on us, we're toast.

[rushingwind]

This was all triggered by an article I read earlier:
http://english.aljazeera.net/news/europe/2011/05/201153222731219991.html

It claims that sea level will rise by 1.6 meters if all the Arctic ice melts. Which is simply not going to be the case.

The continents are not like mounds of dirt with water rushing in on them. The lithosphere, the solid crust of rocks, rides on the squishy, partially molten asthesnosphere. The asthenosphere is part of the upper mantle, and while it’s partially molten, the mantle beneath it is not. The asthenosphere is the zone where the pressure isn’t great enough to keep the rock solid, but not light enough to let it completely melt. You get what geologists call “rotten rock.”

There is a very observable thing called isostatic rebound that none of these “sea level is going to rise” articles are taking into account. Glaciers are heavy. Very heavy. When they sit on top of the crust, they push down hard on the squishy asthenosphere. When the glaciers melt, what does the land do? It rises when the weight has been removed (and by “land,” I mean the entire plate). It’s like sitting on a chair mattress, and then watching it expand back to its original height once you stand up. The mattress compressed because you were sitting on it. Well, land is the same way. In fact, isostatic rebound is still happening from the last major ice age in the Pleistocene. The continental plates are still rising.

Another thing: Sea level is not constant all over the world all of the time. There’s an average, called the “mean sea level,” but it’s not a universal constant that we should be striving for. There are many factors that go into what determines sea level… not just the amount of water out there.

Anyway, this took way too long to write, and I feel like I’m probably about to have my tail handed to me by the good debators out there (I am not a very persuasive speaker, let me tell you). And who knows, maybe some of my own information is faulty. I’m sort of curious what everyone thinks about this matter.

[hiddensquire]

I categorize global warming as irrelevant regardless of whether it is true or not, because ozone is even easier to artificially create than it is to destroy.  If for whatever reason the ozone layer breaks down in an important spot, set up a giant tesla coil there or something and you're good to go after a while.  Someone might say that would be upsetting the natural balance, and perhaps it would, but again, it would be just as easy to destroy some more ozone if the earth started spontaneously generating more ozone than is healthy to support human life.  Nature does not always know best; as you said yourself, it gets species killed once in a while.  You can bet that we're not going to stand by and let that happen to us.  We are the masters of this world.

Now, other forms of environmental pollution, those are real concerns.  Again, the technology exists to make the environmental impact of all the pollution we generate pretty much nil, but it can definitely make things more expensive for the would-be polluters and not everyone follows safe practices.

I did find what you had to say rather interesting, though, rushingwind.  I've largely been ignoring the global warming debate up until this point for the reason I stated at the beginning of this post (and because I hate politics), so quite a bit of that was new information to me.

[Syna]

I'm looking forward to any discussion on this topic, as it's of great concern to me and I'm woefully ignorant about it.

I did briefly ask my friend's geologist sister about climate change once, since geologists compromise of the most global warming skeptics of any repute. She works overseas for a very prestigious oil company. This was her watered-down take as I remember it:
1) Many scientists are politically motivated. However, most geologists work for oil companies, and one pays a lot better than the other. Don't forget this.
2) Geologists, being human beings, tend to resort to what they know and dismiss the findings of other fields: in short, she said that they rely too much on data regarding paleolithic climates and don't look at the evidence other scientists have accumulated seriously enough.

Doesn't help very much, but that's at least one way to start thinking about a response to this, yes?

[Lord J Esq]

I categorize global warming as irrelevant regardless of whether it is true or not, because ozone is even easier to artificially create than it is to destroy.

I don't understand what the thickness of the ozone layer has to do with global warming. Could you explain it for me?

[hiddensquire]

I categorize global warming as irrelevant regardless of whether it is true or not, because ozone is even easier to artificially create than it is to destroy.

I don't understand what the thickness of the ozone layer has to do with global warming. Could you explain it for me?

That statement smells like bait, but I will give you the benefit of the doubt.  Here is the relation between ozone and global warming as I understand it:

The ozone layer plays a huge role in absorbing the majority of incoming UV radiation, which can be devastating to life in large quantities.  In the process of absorbing this radiation, the ozone layer, which is located in the stratosphere, stays heated; this provides a kind of stabilizing temperature buffer effect on the lower troposphere.  A lack of ozone will cause a lot of UV to get into the troposphere, which does heat the troposphere a bit, but the temperature in the stratosphere drops drastically because there's less ozone to produce heat.  Overall, the cooling stratosphere cools the troposphere more than any direct heat it got from UV exposure.  So, to break it down: more ozone = warmer planet, and the converse is also true.

Adjust desired ozone level as necessary.  Also, ozone is toxic for humans to breathe, so don't stand around next to anything generating it for too long.  It floats safely into the stratosphere on its own eventually.

[Thought]

Ozone problems have more to do with protecting us from harmful radiation, whereas other pollutants ("greenhouse gasses") more relate to temperature. Technically ozone does contribute to the greenhouse effect, but then again, so does water vapor. Ozone is a comparatively minor contributor. Carbon dioxide and methane tend to be the most problematic gasses, and while they have natural sources, they also have man-made sources well.

But let us set that aside for a moment. Hiddensquire, your assumption that we can control ozone levels sufficiently so as to negate global warming is inherently flawed. It takes energy to artificially create ozone; where is that power coming from? If it is traditional fossil fuel sources, then by attempting to produce additional ozone we'd also be producing additional pollutants that would be requiring us to produce more ozone which would... and so on. We'd need to use alternative energy sources for that to be vaguely efficient, but if we switch to alternative energy sources, then the need to do this in the first place decreases significantly.

It is indeed possible for us to directly clean up pollution, but this becomes an incredibly energy-wasteful process. The entire reason there is so much pollution is because people have been trying to get cheap energy. If we waste energy on cleaning up pollution, then more energy would need to get produced, which would mean that there is more to clean up.

You general stance is akin to saying that since there are medical ways to treat a heart attack, one shouldn't attempt to avoid getting a heart attack in the first place. The best problems are those that are avoided.

RushingWind, three things. First, I just noticed that you are guru of life. Congratulations (yeah, I am lame and slow at figuring that stuff out). Second, you might be interested in the book The Organic Machine: The Remaking of the Columbia River by Richard White (actually, Josh, you might find it interesting too: it involves dams). It doesn't address climate change but rather our direct impact on the environment. Third, I would comment more, but alas I have too much work to do. Hopefully soon, but I wanted to make sure you knew people were interested in it.

[FaustWolf]

Looks like there's a time series analysis study called "Global Warming Is Driven by Anthropogenic Emissions: A Time Series Analysis Approach", which I want to look into once I find a way to access the article without paying an academic journal subscription. Argh, I hate it when knowledge is locked up in academic journals. I'd prefer little ad popups to the subscription approach, but that's another conversation entirely I suppose.

Otherwise, I must admit I'm taking our impact on global warming on about as much faith as I take the existence of the legendary quark. I've been amazed at how many economics profs I've taken classes from question global warming; their beef seems to be that it would suck to waste a bunch of effort combating something humanity has very little impact on in the end.

Seems to me that whatever the case is, human civilization should start planting a shiteload of trees. Bonus if they're somehow white, as perhaps that would increase our albedo.

[hiddensquire]

Thought, you make a solid point on ozone not being the only major contributor to any would-be global warming, and I was aware of this, but I was going for the first example that came to my mind rather than an exhaustive list.  I apologize if it seemed like I misrepresented ozone as the only player in global warming.  I am also aware of the amount of energy it would take to transform mass amounts of offending air molecules into less harmful molecules.  And my attitude on the matter appears careless not because I believe that preventative measures aren't important, but rather that I believe my beliefs will have no impact on whether or not the majority of polluters keep polluting.  I know human behavior pretty well, and I can say with a fair degree of confidence that environmental practices on a global scale are not going to drastically change from what they are currently until we are already on the brink of disaster, assuming such a disaster does indeed happen.  In the event of such imminent doom, you can bet that the world will also find the motivation to switch to 100% alternative energy solutions at the same time.  Thus, concerns about burning fossil fuels to eliminate fossil fuel emissions are a non-issue.

[Ramsus]

I categorize global warming as irrelevant regardless of whether it is true or not, because ozone is even easier to artificially create than it is to destroy.

I don't understand what the thickness of the ozone layer has to do with global warming. Could you explain it for me?

That statement smells like bait, but I will give you the benefit of the doubt.  Here is the relation between ozone and global warming as I understand it:

The ozone layer plays a huge role in absorbing the majority of incoming UV radiation, which can be devastating to life in large quantities.  In the process of absorbing this radiation, the ozone layer, which is located in the stratosphere, stays heated; this provides a kind of stabilizing temperature buffer effect on the lower troposphere.  A lack of ozone will cause a lot of UV to get into the troposphere, which does heat the troposphere a bit, but the temperature in the stratosphere drops drastically because there's less ozone to produce heat.  Overall, the cooling stratosphere cools the troposphere more than any direct heat it got from UV exposure.  So, to break it down: more ozone = warmer planet, and the converse is also true.

Adjust desired ozone level as necessary.  Also, ozone is toxic for humans to breathe, so don't stand around next to anything generating it for too long.  It floats safely into the stratosphere on its own eventually.

It was bait. The two topics of global warming and ozone layer depletion are considered different issues for a reason.

Ozone is denser than normal air. Close to the earth, it will not rise, but instead fog down around cities and valleys, causing air pollution problems. Just look at its molecular weight versus O2 and N2. You can't fix the ozone layer by simply producing more ozone.

Our concern with the ozone layer and its destruction is based purely on its UV-radiation absorbing properties. Without the ozone layer, most of that radiation that was previously turned into conductive heat by the ozone would continue on to the surface of the earth, wreaking havoc on living creatures like ourselves. If that radiation were simply absorbed by the troposphere, we wouldn't worry about the ozone layer's destruction. That's why the use of Freon and many other CFCs is regulated and restricted -- the ozone layer is too important as a shield protecting us from high intensity UV-induced cancer.

Global climate change is a different topic having to do with greenhouse gases essentially trapping the infrared radiation emitted from the earth's surface so that it returns instead of escaping into space. Water vaper and even ozone have some greenhouse gas properties (meaning more ozone would actually trap more of the earth's radiated heat) but the main concern is the rapid increase in carbon dioxide and methane over the last century and a half.

As this greenhouse effect intensifies, temperatures will generally start increasing due to the returning infrared radiation, causing more water vapor to rise into the atmosphere, which traps even more heat. In other words, increasing temperatures create a sort of feedback loop that increases temperatures, so a relatively small amount of greenhouse gases can have a large impact on the climate.

Certainly, there may be some minor complex relationships between ozone depletion and global warming beyond our understanding (the UV radiation hitting the surface due to ozone depletion might raise surface temperatures and increase some troposphere temperatures during the daytime, but the decrease in ozone would also mean more infrared radiation emitted from the surface of the earth would escape into space, having a cooling effect, especially at night, and in general, climate and weather prediction is difficult, to say the least), but those types of relationships are difficult to understand and explain, yet alone predict. As such, our main concern with either issue is completely different and based on what we can supposedly predict.

With Ozone layer depletion, our concern is the release of CFCs which destroy massive amounts of ozone in the atmosphere and the increase in high intensity UV radiation that reaches the surface because of that. Meanwhile, with climate change, our concern is with the buildup of greenhouse gases and the unpredictable (and thus undesirable) climate changes that result.

EDIT:

That can hard to explain in English; now imagine explaining all that in Korean. One of my instructors when I was in Seoul studying Korean on OCONUS immersion had also conflated together the issues of global warming and ozone layer destruction. We were only allowed to use Korean, and I had a hell of a time trying to get her to understand that there was even a difference.

[hiddensquire]

Well now, that's interesting.  It does make sense that 0₃ would be heavier than 0₂, but I just kind of assumed it was somehow lighter than air as a whole because how else does the existing ozone layer stay up in the stratosphere?  Centrifugal force?  In any case, given that information, you'd have to use a space elevator to deliver ozone to the desired atmospheric layer (and possibly release it with some kind of lateral thrust to keep it floating in orbit).  Rockets would be 100% counter-productive, emission-wise.  My solutions just keep getting more and more expensive, don't they?  For the non-ozone greenhouse gases, the solution is pretty much to plant a ton of plants/trees or to build large machines to suck in mass quantities of air, filter it a bit, and convert the offending gases into something else.  Yeah, guess which one is easier?  Also, I never stated at any point that the troposphere absorbs all or even most of the UV, just a portion of it.

A major issue with the tree planting idea is that we are actually actively deforesting the planet right now.  For example, the conversion of the amazon rainforest into farmland.  The people clearing it have real survival needs, and the clearing won't stop until those needs are met in some other way.  Part of the problem is that the newly deforested areas only stay fertile for a short time before the farmers have to either move on to the next area or switch to animal farming.  Bio-engineered plants (I hear soybeans are a popular product down there; maybe start with that?) designed to thrive in less fertile environments could help greatly.

Anyway, I'm kind of derailing the main topic here, which is whether or not man-made global warming is a real issue.  I'll stop now.

[Ramsus]

Well now, that's interesting.  It does make sense that 0₃ would be heavier than 0₂, but I just kind of assumed it was somehow lighter than air as a whole because how else does the existing ozone layer stay up in the stratosphere?  Centrifugal force?  In any case, given that information, you'd have to use a space elevator to deliver ozone to the desired atmospheric layer (and possibly release it with some kind of lateral thrust to keep it floating in orbit).  Rockets would be 100% counter-productive, emission-wise.  My solutions just keep getting more and more expensive, don't they?  For the non-ozone greenhouse gases, the solution is pretty much to plant a ton of plants/trees or to build large machines to suck in mass quantities of air, filter it a bit, and convert the offending gases into something else.  Yeah, guess which one is easier?  Also, I never stated at any point that the troposphere absorbs all or even most of the UV, just a portion of it.

A major issue with the tree planting idea is that we are actually actively deforesting the planet right now.  For example, the conversion of the amazon rainforest into farmland.  The people clearing it have real survival needs, and the clearing won't stop until those needs are met in some other way.  Part of the problem is that the newly deforested areas only stay fertile for a short time before the farmers have to either move on to the next area or switch to animal farming.  Bio-engineered plants (I hear soybeans are a popular product down there; maybe start with that?) designed to thrive in less fertile environments could help greatly.

Anyway, I'm kind of derailing the main topic here, which is whether or not man-made global warming is a real issue.  I'll stop now.

Think about what's different about ozone in the stratosphere.

The ozone in the ozone layer is constantly heated by the UV rays it absorbs, giving it energy -- just look at a temperature gradient chart of the atmosphere. All gases expand in volume and pressure as they rise in temperature, making them less dense. Since hot ozone is less dense than O2 and N2, it stays above the troposphere. Ozone in our cities is the same temperature as all the other gases, and any heat energy it gains from radiation is quickly lost to its surroundings (namely all the O2 and N2 around it), keeping it denser than normal air. So ozone in the stratosphere stays up there, while the ozone pollution in our cities tends to stays down here.

But how did the ozone originally get there? It formed there.

UV radiation will knock apart O2 molecules and allow them to form into O3 molecules. As an aside, The ability to knock apart certain molecules is the main reason UV radiation is dangerous to us -- it does the same thing to our DNA molecules, causing the genetic information in those cells to change and thus forming mutations that may be cancerous.

If ozone naturally forms in the atmosphere, then why are we even concerned with ozone layer destruction? CFCs destroy ozone a dozen times faster than it's created.

By releasing tons of CFCs into the atmosphere, we quickly destroy the ozone much faster than it can ever be created naturally, kind of like how irrigation often sucks rivers dry, screwing over everyone downstream. Except unlike a river, a dried out ozone layer could take decades to replenish itself, leaving plenty of time for the UV radiation raining down on everything to wreak havoc on all surface life.

So what's the solution? Stop releasing CFCs and other ozone destroying chemicals into the atmosphere.

It's that simple.

[GenesisOne]

I only know so much about global warming based on the limited research I have done on it, but here's the conclusion I have honestly come to:

Global warming is real and most of the recent increases in temperature are directly the result of human actions. However, a number of predictions publicized in the media present unrealistic scenarios of doom and gloom. Yes, sea levels are likely to rise, but certainly not 3 feet within this century as some outlets have publicized.

Temperature increases have been extremely rapid within the last two decades. However, the pattern of global temperature increases has never been directly proportional to increasing CO2 levels in the atmosphere. It is likely that a downturn in temperatures will occur within the next two decades. At that point, the global warming naysayers will proclaim global warming to be a myth. However, I expect temperatures to head up sharply again soon thereafter. If temperatures do not decrease in the near future, at the current rate, temperatures would be 2°C higher by the end of the century.

Some climate models have predicted temperature increases of up to 9°C with a doubling of atmospheric CO2. However, two studies, using different techniques, have constrained the maximum temperature increase to between 1.5°C and 4.5-6.2°C. In order for temperatures to increase at the maximum predicted amount, the rate of increase would have to remain upward the entire time and increase dramatically.

Changing temperatures and ocean currents will cause droughts in some parts of the world, while other areas become moister. However, droughts have been with humanity since the beginning of recorded history, and would have continued to occur even in the absence of global warming. The existence of some species will be threatened by the consequences of global warming. However, according to Darwinian theory, these poorly adapted species will be replaced by newly evolved ones. Of course, not even scientists believe that this will really happen.

Governments and individuals should work to seriously address the issues of CO2 emissions and carbon sequestration. The primary emphasis should be switching from fossil fuels to alternative energy sources and expansion of northern forests. How realistic the former plan of action will be is another story, but so far, the alternatives don't look all that promising.

Not being an expert in climatology, it is possible that I have made some errors in my summation. By all means, correct me where I'm wrong on anything I have said so far.

[Thought]

As a related issue to climate change, melting glaciers have more of an effect than just rising sea levels. They're made of freshwater, so as they melt they change the salinity of their surrounding waters (and, indeed, eventually the oceans themselves). This kills off not just the fish that humans gather, but also other sea creatures that are necessary for atmospheric cycles. Thus, as the caps melt, the oceans will not trap as much carbon and other greenhouse gasses, so those will build up quicker, causing more change, etc.

[FaustWolf]

Damn, it's impressive watching everyone's scientific knowledge accumulate in one place like this!