Eocene and Global Warming

[Felch]

I was bored at work, so I started looking at different geological ages on wikipedia, and one jumped out at me.

Eocene on Wikipedia

In brief, the Eocene was about 40-55 million years ago. While the continents were shaped a bit differently (South America was connected to Antarctica, but not North America) it still might have applications to the modern debate on global warming.

Marking the start of the Eocene, Earth heated up in one of the most rapid (in geologic terms) and extreme global warming events recorded in geologic history, called the Paleocene-Eocene Thermal Maximum or Initial Eocene Thermal Maximum (PETM or IETM). This was an episode of rapid and intense warming (up to 7°C at high latitudes) that lasted less than 100,000 years. The Thermal Maximum provoked a sharp extinction event that distinguishes Eocene fauna from the ecosystems of the Paleocene.

The Eocene global climate was perhaps the most homogeneous of the Cenozoic; the temperature gradient from equator to pole was only half that of today's, and deep ocean currents were exceptionally warm. The polar regions were much warmer than today, perhaps as mild as the modern-day Pacific Northwest; temperate forests extended right to the poles, while rainy tropical climates extended as far north as 45°. The difference was greatest in the temperate latitudes; the climate in the tropics however, was probably similar to today's.

I don't claim any expertise on this, but it does seem to give further weight to an old problem I had with the debate on global warming - it's always assumed to be a bad thing.

While the Eocene was a time for mass extinctions, it also was the time when many new types of animals first appeared, including primates. It seems almost like an paradise planet, with the ice caps melting into temperate regions, and the tropics staying more or less the same.

Does anybody else get the feeling that global warming might actually be a good thing, and that all this carbon cutting might be counter productive? Or is the planet too different to apply the lessons of the Eocene to our situation?

[BeBMan]

Depends on who'll be on the mass extinction side.

[Felch]

Based on past experience, it probably won't be cockroaches.

We'll likely see the demise of polar bears, some penguins, the rest of the arctic lifeforms, and heaping piles of specific algae or plankton or such.

Perhaps the demise of arctic feeding grounds could wipe out whales.

The thing is, it's impossible to know. Animals adapt and evolve to changing conditions all the time.

[Arrian]

While the Eocene was a time for mass extinctions...

That's your problem, right there. We're dependant on a whole lot of living things that might up and die on us.

There will be an awful lot of disruption.

The polar regions were much warmer than today, perhaps as mild as the modern-day Pacific Northwest; temperate forests extended right to the poles, while rainy tropical climates extended as far north as 45°. The difference was greatest in the temperate latitudes

Who lives in temperate latitudes? Hmm. USA, Canada, Europe, large parts of China, Japan... that's just the northern temp. zone. And how much of that population is coastal?

-Arrian

[Felch]

Extinctions happen - they're a natural part of evolution.

People can move, both inland and towards to poles. I don't think flooding from global warming would occur like a tsunami, but rather as a gradual rise that can be predicted and accounted for. If other people know better, I'm willing to hear them out.

[Arrian]

Yes, they happen normally. That doesn't make it good news for us.

People can move, both inland and towards to poles. I don't think flooding from global warming would occur like a tsunami, but rather as a gradual rise that can be predicted and accounted for.

Sure. But people being people, the likely result will be that cities on the coasts will build seawalls/levees/etc in an effort to sustain themselves in their current locations (really, how easy will it be to say "well, time to abandon Manhattan"). Those will hold for a while, but eventually you will have Katrina-style events (storm + bureacratic incompetance = big mess). Only after such disasters will people move inland.

My point isn't that we will necessarily face extinction. It's that there will be an awful lot of disruption. Disruption isn't a good thing - especially when you have lots to lose.

-Arrian

[Felch]

Disruption is a bad thing, but I wonder if people consider the cost/benefit analysis when they form policy.

If it costs trillions of dollars to fight global warming, it might be better just to let it happen and spend a fraction of that amount on levees to protect our cities.

[Felch]

I guess my big problem is that this whole debate seems like a bandwagon. Every scientist agrees that global warming is the number one threat to our society. But remember five years ago when every intelligence agency agreed that Iraq had WMDs.

Sometimes people just go along with things because they trust the experts too much.

I agree that the world is getting gradually warmer, and I think it probably has something to do with all that CO2 we've been dumping in the atmosphere. I just wonder if it's all doom and gloom, or if it could be a blessing in disguise.

[Fake Boris]

Originally posted by Felch
I guess my big problem is that this whole debate seems like a bandwagon. Every scientist agrees that global warming is the number one threat to our society. But remember five years ago when every intelligence agency agreed that Iraq had WMDs.

[Riesstiu IV]

Any animal that doesn't survive global warming is an arsehole and needs to harden the **** up. Survival of the fittest.

[Arrian]

Originally posted by Felch
Disruption is a bad thing, but I wonder if people consider the cost/benefit analysis when they form policy.

If it costs trillions of dollars to fight global warming, it might be better just to let it happen and spend a fraction of that amount on levees to protect our cities.

There's no real way to do a proper cost-benifit analysis. We don't really know all of the outcomes of GW, and all the downsides (and possible upsides) to it. I'm not even sure we're all that good at estimating the economic cost of curbing emissions (couldn't there be unknown economic upside there?) So there's no real way to sit down and tally it up "ok, $50 trillion to stop it, $48 trillion to let it happen and deal with it. WINAR!"

-Arrian

[Felch]

Originally posted by Arrian
There's no real way to do a proper cost-benifit analysis. We don't really know all of the outcomes of GW, and all the downsides (and possible upsides) to it. I'm not even sure we're all that good at estimating the economic cost of curbing emissions (couldn't there be unknown economic upside there?) So there's no real way to sit down and tally it up "ok, $50 trillion to stop it, $48 trillion to let it happen and deal with it. WINAR!"

-Arrian

Right, so if we don't actually know what is going to happen, or what it will cost to fix it, why is there this "consensus?" It seems like a couple key people became convinced of a problem (the cool scientists I suppose) and everybody else just jumped on the bandwagon and signed whatever document the IPCC put in front of them.

[chequita guevara]

The Pentagon also agrees that climate change is a considerable menace to our society.

You need to keep in mind, however, that the Eocene and Holocene eras had difference responses to global warming because of the configuration of the continents. The current configuration is largely responsible for the ice ages, because the warm currents that flowed from the Pacific into the Atlantic no longer can get through (duh). Weather patterns are thus likely to be very different, with substantially more desertification.

The big fear, however, is that global warming could trigger a shut down of the global currents, which would lead to a new ice age. Current thinking is that an asteroid strike ended the last one, so I'm not really sure we want to risk a new ice age, though we might be able to nuke the ice sheets.

[Felch]

Originally posted by chegitz guevara
The Pentagon also agrees that climate change is a considerable menace to our society.

Which brings us back to the WMDs. Since when did you ever believe the Pentagon, Che?

You need to keep in mind, however, that the Eocene and Holocene eras had difference responses to global warming because of the configuration of the continents. The current configuration is largely responsible for the ice ages, because the warm currents that flowed from the Pacific into the Atlantic no longer can get through (duh). Weather patterns are thus likely to be very different, with substantially more desertification.

Yeah, that was mentioned in the wikipedia article. I'm not an expert on these sorts of things, so I'm not sure how far the science has come. However, I take these sorts of predictions with a grain of salt, because the models they're based on are inherently untested.

The desertification puzzles me. Wouldn't hotter air carry more moisture than cooler air? Antarctica is a massive frozen desert, while the equatorial regions are predominantly tropical rain forest. Warming leading to deserts seems counter-intuitive, although I imagine that the changes in ocean currents could have unpredictable effects.

I'd say that the effects of continental drift are too complex to understand and model accurately. It's not possible to figure out what will happen until we actually see how it turns out.

The big fear, however, is that global warming could trigger a shut down of the global currents, which would lead to a new ice age. Current thinking is that an asteroid strike ended the last one, so I'm not really sure we want to risk a new ice age, though we might be able to nuke the ice sheets.

This is what really bothers me about the whole debate. Nobody seems to know what will happen, but everybody is sure it will be bad.

I'm sorry if I seem flippant, or overly skeptical, but when you can't trust a five-day weather forcast, why should you believe a bunch of contradictory climactic models? Why should we base trillion dollar policies on guesses and fear mongering?

What if global warming turns out to be the greatest thing to ever happen? What if the loss of coastal land is more than balanced by the warming of marginal land in the arctic circle? What if increased CO2 gives plant life the edge we need to make food more readily available to a growing population?

Or what if - and this is the most likely outcome - some things improve, some get worse, but the overall picture is still pretty much the same. Why should we focus on this when there are little kids dying of preventable disease, and women being abused by drunk husbands, and river fish being killed off by industrial pollutants, and all the other problems we have? Why are we looking for problems that might not exist (Iraq), instead of solving the problems we already have (Afghanistan)?

[Arrian]

river fish being killed off by industrial pollutants...

This, to me, represents a nice dovetailing of interests. I am personally more interested in cleaner air and water than I am in combatting global warming (since I see the contaminated drinking water and toxin-laced air as a tad more... concrete), but it seems to me that switching from coal plants to more solar and wind does it all. Nuclear... less clear. The waste is still a major problem there.

-Arrian