It shows that you don't get that it's the Industrial Revolution which is the culprit - not pre-industrial people who probably killed off some megafauna.

You surprise me every time. That's what keeps me coming back for more, I think! So, you accept that humans have caused global warming, and are responsible for our current "elevated" rate of extinctions. You just don't think the rates are especially higher now than 10,000 years ago. In particular, you don't blame industrialization for any noticeable (or, I should say, problematic) increase in extinction rate. Is that an accurate assessment?

Agreed 100%. Unless, in some unlikely scenario, we somehow survive a great cataclysm in the margins, bereft of our technological civilization.

Agreed.

Agreed.

You could be right. In fact, you're probably right. But the critical thing we need to figure out is: how do we make people wealthy without further destroying the environment? And going forward, we need to figure out how to _reduce_ our environmental footprint.

Here I disagree completely. It's absolutely critical that we figure out, poste haste, how to get energy some other way than from fossil fuel. We have massive amounts of energy raining down on us. We're just too technolgically undeveloped to know how to make use of it. Why? Because companies don't have to pay anything for the damage they do to the environment.

What a carbon tax does is to say, "Look, you can put CO2 into the atmosphere. But when you do, you take something away from everyone else who lives on the planet. Therefore, you must pay for the mess you make." It's very straightforward, sensible, fair, etc. It's outrageous that we don't do that now.

If we were to do that, the market would start finding the solutions to our problems.

I see. So you've rationalized to yourself that these extinctions are just the continuation of a trend which started 10,000 years ago (the megafauna?), and have nothing to do with us.

I would start by pointing out that humans quite possibly hunted the megafauna to extinction. But beyond that - seriously! The opinions you have developed are rooted in ignorance. There is a very strong correlation between human industrial development and species extinction. The extinction rate far surpasses anything that could be considered "normal".

"Rapid", in geological terms, is a much longer process than what we're doing to the Earth right now. An exception would be something like the K-T boundary, where the Earth was probably plunged into something like a "nuclear winter" for perhaps 10 years. The result was the extinction of almost all the dinos.

AGW is only part of the damage we're doing. Acidification goes along with it - including ocean acidification. But habitat destruction is no doubt the largest component. In the past, land animals could migrate to more suitable areas as the climate changed. That's becoming increasingly impossible.

In short, AGW will deliver a hammer blow to the scattered remnants of the natural world we have devastated. At least, to the complex land animals.

It is an uncomfortable fact that human industrial development is doing major damage to Earth's ecosystems. What is needed is A) for people to learn what the real situation is, rather than being fed lies by industrial interests, and B) to begin the process of undoing the damage we've caused.

How exactly do we accomplish this? That, I don't know. But at least I don't pretend it doesn't need to be done.

You're being very blasé about the whole extinction thing. You seem uncertain that it is even happening. Let's look at our own order - the primates. According to http://www.usatoday.com/story/... (first google hit), 25 are on the brink of extinction. It goes on to say "More than half of the world's 633 types of primates are in danger of becoming extinct" (where "type" must be referring to sub-species). How about amphibians - again, first google hit for "amphibian extinction, at http://www.nzfrogs.org/Amphibi...: "... 32% of all amphibians are threatened with extinction.". Google "cat extinction" and we find this article: http://www.facekitty.com/2008/..., about 12 wild cat species that will be extinct by 2020 (out of, apparently, 36 wild cat species total). Sure, it's not a scientific journal. But I mean - please! This information is not hard to come by. It goes on and on. Pick a random complex animal genus, and see how its species are doing.

Is this a case of willful ignorance on your part? Or are you willing to admit that we "are" in a major extinction event, rather than "may be"? You have seemed ready to go along with the scientific consensus so far....

You have never responded to the 6th Great Extinction issue.

It _does_ matter if we wreck our environment. Most people - Americans the same as everyone else - get that. The hangup for too many of _them_ is that they don't accept that A) global warming is happening, and/or B) that it being caused by humans. You, on the other hand, readily accept what the scientific community has so resoundingly concluded vis a vis AGW. Your whole position is based on the idea that wrecking our environment doesn't matter!

I have to admit - that's a new one for me. How can you sustain that idea in your head? Do you not understand how utterly dependent we are on the Earth? How tenuous is our position? I'm not talking about our lifetimes. Start thinking like a member of a species, rather than a single selfish individual.

How can you say it's not going to be a problem for centuries to come, when it's already a huge problem, and we've already got decades more pain loaded into the pipeline? What does it take for something to rise to the level of "a problem" for you? When your ocean-front property is under the waves? I'll grant you, that might not occur for centuries to come (depending on the elevation of your property and rates of Greenland/Antarctic ice melting). Is it only "a problem" if you're uncomfortably hot? Does the ecosystem matter at all? Does the unprecedented (since the dinos) rate of species extinction come into play in your thinking? Or are those going-extinct species just another greedy vested interest?

Money is what they have to gain. Energy companies (and the stock market) treat fossil fuel reserves as money. If it cannot ultimately be burned, that means the energy companies don't have that money after all - so they lost money directly. How much money? According to http://qz.com/139907/climate-c... (my first Google hit), about $6 trillion. Now _that_ is money! And it doesn't end with energy companies.

Ultimately, the issue is that we all depend for our delicate existence on the health of our Earth. And yet, companies pay no costs when they damage our Earth. Therefore, they have and will continue to do what any good profit-maximizing enterprise would do in such circumstances: not care about damaging the the Earth!

You can't seriously believe this. You're going to equate the $6 trillion which energy companies have at stake, with, essentially, book sales. That's what I anticipated you would do earlier in the discussion. I was hoping you'd come up with more than that.

I'll spell out the discrepancy. From the Yale report:

And yet, as I think you and I agree, there is in fact an overwhelming consensus among climate scientists that global warming is occurring. And I think it's fair to say that it's a given that it is ultimately caused by what is termed "economic growth".

If all Americans understood that A) global warming is occurring, and B) we are causing it, then I think you'd find much stronger support for action. Why? Because most people are not like you. Most people are, I think, willing to take some pain now for the benefit of coming generations. Your ideas about climate are reckless, to say the least. Most people aren't so reckless.

What "agenda" do you imagine the environmentalist lobby has, anyway? It's clear what the industrialists have to gain in trying to discredit climate scientists (and science generally, as fallout). But what ulterior motive (other than just trying to preserve the environment for future generations) do you imagine environmentalists have? Please don't tell me it's all about selling books!

I refer you to this analysis of American attitudes toward global warming issues: http://environment.research.ya... (produced in 2007).

Short blurb from the beginning:

What is striking is that there is ovewhelming consensus among climate scientists that global warming is occurring, and that it is being caused by humans - in effect, by "economic growth".

How do we explain the discrepancy? In part, I think, because people have a vested interest in believing that there is no problem with their lifestyle. But in a more sinister vein, the problem is that in their efforts to counter the solid scientific consensus, vested industrial interests have been marketing anti-scientific ideas to the general public. These efforts have had some success. Unfortunately, loss of scientific literacy among the general public has been part of the collateral damage.

So, no worries - full steam ahead!

Ooops - missed a close quote! Here goes again...

Which I guess you're comfortable with. In any case, what makes you so certain about this limit? Estimates for the amount of recoverable fossil fuel keep going up over time. In part, this is due to new discoveries. In part, it is due to improved extraction technologies. And then there's the combination: when we come up with a new technology which lets us exploit a whole new category of fossil fuel (e.g. clathrates).

Who's to say what will be recoverable in the future?

Is there any level of atmospheric CO2 which would cause you to worry? And if so, what would you propose doing about it?

I'm not sure what point you're trying to make about the primates. You seem to be suggesting that primates - or at least humans - are highly adaptable, so no worries about climate change. In fact, primates are rapidly going extinct. The most complex primates - great apes - are the most at risk. Excluding us, of course.

What's happening right now, as we speak, is the 6th Great Extinction event, evidently caused by the exponential economic growth of humans. This is partly due to habitat destruction, and partly due to the global warming (and other environmental change, like ocean acidification) already carried out by us. And there's much more to come which is already "in the bank", regardless of what we do right now.

You see, in times past, when global conditions changed, creatures were able to roam to new areas, increasing their chances for survival. We have shut that process down in a major way.

I see what you did there. Very clever!

So what you're saying is, as long as we don't get to a runaway greenhouse effect, we're good! I agree with you part-way: if we do get a runaway greenhouse effect, we're done for.

Let's revisit the numbers.

                                800 gtc in atmosphere
                                1,500 gtc in surface biomass (ocean + land)
                                2,300 gtc in soil
                                6,000 gtc in deep-ocean "reactive sediments" (clathrates, I assume)
                                10,000 gtc in fossil fuel
                                27,000 gtc in deep-ocean sediments

The bolded ones are potentially available to be dumped back into the atmosphere, once we figure out how to get to them.

800 gtc puts us at the present 0.04% CO2. If we dump all 16,000 gtc of potential fossil fuel in the atmosphere, that would put our levels up by a factor of 20. In ppm terms, we'd be in the vicinity of 8000 ppm. You're quite confident that at 2000 ppm, we would not have a runaway greenhouse effect which would surely kill us all (and perhaps all other complex life). Are you as confident at 8000 ppm?

The proto-dinos were the ones who survived the most devastating extinction event - the Permian - which was a long-term environmental-change situation. While the dinos were enjoying an adaptive radiation, the remaining proto-mammals lived in the margins thru the Dinosaur Age - perhaps detritus-eaters living underground. The K-T boundary appears to have been an asteroid which probably incinerated all plant life, causing the most complex creatures - the tops of the food chain, i.e. the dinos - to die off.

Mammals are delicate. There are lots of ways for us to go down. Complex is not good, in terms of being a hardy survivor.

I responded to this comment of yours:

"... even if we burned all of it, we'd still be on a livable planet (where do you think fossil fuel came from?)"

As I have demonstrated, it is fallacious to assert that because the fossil fuel was once non-fossil, and living things got along just fine, that it would be OK if the carbon were once again in the biosphere - what's the big deal?

What we have to do is to consider our actual circumstances now. It matters not to us whether some other creatures in some other time could survive the environmental conditions we are propelling ourselves into.

Concerning the Cretaceous, there is a critical factor you have not considered. The so-called fossil fuels (i.e. carbon laid down by land plants eons ago) was deposited in the Carboniferous, i.e. around 300 million years ago - i.e. before the dinosaurs. The term "dinosaur juice", referring to oil, is misleading. During the dinosaur period, the vast fossil fuel deposits were already - deposited. If the dinos ever figured out how to burn the fossil fuel, they'd be in the same trouble we are today.

If only they'd had another few million years of evolution before getting slammed by that hunk of space rock, they just might have gotten there, too! In which case they would possibly have wiped both themselves and us proto-mammals out along with them. So it's a good thing they got wiped out first. Now we have the honors of wiping ourselves out, possibly along with the last remaining dinos - the birds.

OK, let's run the numbers on fossil fuel. Here's the total inventory of the biosphere's carbon. "gtc" means giga-tons of carbon. All the numbers are in terms of carbon alone.

                800 gtc in atmosphere
                1,500 gtc in surface biomass (ocean + land)
                2,300 gtc in soil
                6,000 gtc in deep-ocean "reactive sediments" (clathrates, I assume)
                10,000 gtc in fossil fuel
                27,000 gtc in deep-ocean sediments

The total is 47,600 gtc. That's 60 times as much carbon as is currently in the atmosphere. Currently, the atmosphere is 0.04% CO2. So, if we put all the fossil carbon back into the atmosphere, we'd have 2.4% carbon dioxide.

Let's even set aside the apocolyptic greenhouse effects this would have. At this level, your own personal well-being would be impinged upon. In an auditorium, at 1% concentration of carbon dioxide, some people begin to feel drowsy. At 2%, most people feel its effects. Above 2%, it may cause a feeling of heaviness in the chest and/or more frequent and deeper respirations. Acidosis (an acid condition of the blood) may occur.

You see, a couple of things have changed since that carbon got fossilized. For one thing, the Sun is hotter. While the Earth used to be on the outside of the habitable zone, now we're on the inside. So while high levels of CO2 may have helped life along on a cold Earth, now that carbon must remain sequestered or we are hosed.

Which brings me to the other thing that's changed. Early, single-cellular life was adapted to whatever temperature the Earth was at. The first life may well have been extremophile - living off the energy of hot water vents on the bottom of the ocean. Life has adapted over the eons, eventually producing complex creatures such as ourselves, which/who are relatively picky when it comes to environmental conditions. What is now being contemplated is a step function environmental change from which Life will have no time to adapt. At least, not complex life like us. I'm sure the bacteria will figure out it. They always do. Clever little fellows.

What you prefer - endless exponential economic growth combined with a liveable planet - is not on offer by the universe we inhabit.