What the Earth Knows

[NovaScotian]

From time to time here in The Coat Room, we've quibbled politely about climate change and/or global warming. Robert B. Laughlin, professor of physics at Stanford University and a co-recipient of the 1998 Nobel Prize for Physics has written an essay in the American Scholar putting all of those arguments into an interesting perspective framework -- geological time; what is known about the history of the earth: What the Earth Knows. He doesn't take sides in the climate change argument so much as point out that it (whatever its cause) is just a blip that has been repeated many times. Well written, interesting read.

[regulus6633]

Interesting read is right, thanks for the pointer. From the perspective of the Earth we will have very little impact. However from our perspective, where years are much more important than geological time, we have a great impact because small variations in global temperature have catastrophic economic repercussions. So I'm not sure this article is relevant to the current concerns of man but it is an interesting read. It certainly does show that as much as we would like the Earth to always stay the way it is today, that is a foolish notion. The Earth is a constantly changing entity and we should expect nothing less.

[NovaScotian]

Quote: Originally Posted by regulus6633 Interesting read is right, thanks for the pointer. From the perspective of the Earth we will have very little impact. However from our perspective, where years are much more important than geological time, we have a great impact because small variations in global temperature have catastrophic economic repercussions. So I'm not sure this article is relevant to the current concerns of man but it is an interesting read. It certainly does show that as much as we would like the Earth to always stay the way it is today, that is a foolish notion. The Earth is a constantly changing entity and we should expect nothing less.

What struck me was just how changeable it has been over the eons of its past. I was also quite surprised at how much is known of its weather over geological time. I agree with you that small variations can have profound effects, however -- if only we understood them!

[regulus6633]

I knew that we could take, for example, ice samples and release trapped gasses from long ago to determine the atmospheric configurations from the past. I knew about carbon dating. I didn't know about the argon dating technique and certainly didn't know that we could put all these facts together to understand so exactly what happened, where it happened, and when it happened. That was the interesting stuff to me. When he made the statement about the energy requirements needed to affect these Earth-sized changes, and how man is no where near big enough to make changes on this scale... that was impressive. And one other impressive point was when he listed all of the theories about why these changes occur and yet we really have no scientific understanding to know which of the theories is correct. They're all just guesses. Cool stuff.

[trevor]

Quote: Originally Posted by NovaScotian He doesn't take sides in the climate change argument so much as point out that it (whatever its cause) is just a blip that has been repeated many times.

Not true. We've never been over 300 ppmv carbon dioxide concentration in past cycles. We're now approaching 400 ppmv CO2.



Trevor

(Note that the graph above looks like we were over 300 ppmv CO2 about 330,000 years ago, but I'm basing the statement above on my tour of the National Ice Core Lab on Friday, where they showed a much better version of this graph and that peak was below 300.)

[NovaScotian]

Quote: Originally Posted by trevor Not true. We've never been over 300 ppmv carbon dioxide concentration in past cycles. We're now approaching 400 ppmv CO2. Trevor (Note that the graph above looks like we were over 300 ppmv CO2 about 330,000 years ago, but I'm basing the statement above on my tour of the National Ice Core Lab on Friday, where they showed a much better version of this graph and that peak was below 300.)

Does this mean that we're headed for another ice age?

[Red_Menace]

That graph looks almost the same as the one for temperature.
http://wattsupwiththat.com/2009/12/0...ice-core-data/

[trevor]

Quote: Originally Posted by NovaScotian Does this mean that we're headed for another ice age?

I believe that the answer to that question depends on how you define 'ice age'. Our guide at NICL said that the fact that we have frozen ice caps means that we're now in an ice age, but we're in an interglacial period.

Trevor

[Jasen]

Quote: Originally Posted by NovaScotian Does this mean that we're headed for another ice age?

Probably. Maybe certainly.
However, looking at the graph given, the cycle time between peaks and lows is roughly 100k years. That's the natural, pre-industrial, non-human-intervention cycle.
So, if we're currently at a peak, we've got a few tens of thousands years before we enter the next ice age, even if this peak is higher than the last few. Even if our influence is unduly raising that peak--we're not going to trigger an ice age within the next few centuries.

That's not to say we should ignore it or not do anything about our emissions and pollution.

[NovaScotian]

Quote: Originally Posted by Jasen Probably. Maybe certainly. However, looking at the graph given, the cycle time between peaks and lows is roughly 100k years. That's the natural, pre-industrial, non-human-intervention cycle. So, if we're currently at a peak, we've got a few tens of thousands years before we enter the next ice age, even if this peak is higher than the last few. Even if our influence is unduly raising that peak--we're not going to trigger an ice age within the next few centuries. That's not to say we should ignore it or not do anything about our emissions and pollution.

I think human intervention began earlier than you think. During the middle ages, rickets (caused by a shortage of vitamin D and/or sunlight) was common in the large cities of Europe because the coal smoke was so thick. Clearly the population of the earth was lower then, but a lot of dirty coal was burned.

[trevor]

At NICL, they mentioned that they can see lead in the Antarctic ice cores more than 2000 years old due to the huge amounts of lead that the Romans were smelting.

Trevor

[roncross@cox.net]

Quote: Originally Posted by NovaScotian I think human intervention began earlier than you think. During the middle ages, rickets (caused by a shortage of vitamin D and/or sunlight) was common in the large cities of Europe because the coal smoke was so thick. Clearly the population of the earth was lower then, but a lot of dirty coal was burned.

Ditto to that. Also read about what happened on Easter island where consuming to many resources drove away an entire population. Also we have shown that we can affect the climate in other ways such as CFC that were depleting the ozone layer.

The real problem of course is population growth. It's stretching the resources beyond our consumptive abilities. I think global warming will become a reality.

Good news for me in Massachusetts as this will drive the price of my house through the roof.

[Jasen]

Quote: Originally Posted by NovaScotian I think human intervention began earlier than you think. During the middle ages...

I think it began as early as 8-5000 years ago when human societies started turning agrarian on a large scale. Clearing (razing) forests for farmland, etc.
It doesn't change my conclusion though. An ice age is still thousands of years away.