Brian Thompson

Regardless of whether it's natural or manmade, why should it be feared? I know many dire predictions are being made by some scientists and activists regarding increasing heatwaves, flooding, drought, extinctions etc and even some of the more cautious types at least predict overall global warming will be A Bad Thing TM (although <a href="http://www.stanford.edu/~moore/Boon_To_Man.html" target="_blank">a few enthusiastically endorse it</a> ). I would be interested to know what historical, geological, fossil etc evidence there is that past natural global warming hampered or threatened human survival or ecological viability in order to give these present claims some validity?

For example, many Arctic or alpine species are said to be threatened by imminent global warming, which makes me wonder how they survived the last four interglacials over the last 500,000 years where often <a href="http://muller.lbl.gov/pages/IceAgeBook/history_of_climate.html" target="_blank">average temperatures were higher than today's</a> (some excellent comparative temperature graphs on different timelines there). How did the polar bears (or the Inuit for that matter) survive the Holocene Optimum of roughly 7000-3000BC where temperatures were <a href="http://www.geog.ouc.bc.ca/physgeog/contents/7x.html" target="_blank">1-2 degrees C higher than today</a> and presumably the Arctic ice cap retreated far beyond its present extent? The <a href="http://www.csmonitor.com/atcsmonitor/specials/athousandyears/ideas/env7.html" target="_blank">Little Climate Optimum of 900-1300AD</a> with 1 degree C warmer temperatures than today seems to coincide with climate stability and positive impacts on human agriculture and civilization as well.

It seems to me regardless of what climate models or certain scientists and activists predict, what's really more important is if these predictions have come or been true in the past. Ultimately, projections, extrapolations, predictions, simulations, whatever you like to call them, have to validated by real world data, real world experience. Regardless of isolated instances of drought here or flooding there, what proxy measurements and historical/prehistoric evidence is there that global warming was generally more detrimental than beneficial to humanity and biodiversity and should be a justifiable concern for the future?

Edited to correct UBB.

[ September 16, 2002: Message edited by: Brian Thompson ]</p>

Jonesy

if you are mathematically able, check this out, although 99% of people would consider it bullshit simply because they don't get the Math:

<a href="http://NUjournal.net/core.pdf" target="_blank">http://NUjournal.net/core.pdf</a>

I'm curious. Is anyone else also at least curious? I'm not good at math and still cannot find some good scientist who could point out to me flaws in the above document. So I remain neutral to the above document.

But one thing is for sure - there is 'some' level of global warming - although no body seems to be EXACTLY sure what levels are good or bad, or even what levels actually exist.

theyeti

Gobal temperature is strongly correlated to CO2 levels over Earth history. Unless you want to argue that increased temperatures are causing increased CO2 levels, then I think it's safe to say that the prediction of global warming has been validated by real world data. There is still some uncertainty, though. the question is how much uncertainty are you willing to gamble on.

It really comes down to an matter of economics. Even a small increase in flooding or circular storms will cause many billions of dollars in extra damage every year, and many thousands of additional lives lost. Arable land will shift to higher lattitudes, and lots of people will have to move. Places that start receiving much more rain will have erosion problems (witness El Nino) and places that receive much less rain will have drought problems. So on and so forth. The problem isn't so much that it's causing warming, the problem is that it's going to cause a lot of change that will be extremely expensive to adapt to.

The problem with the evidence you cite is 1) past climate changes for the most part, including glaciations, took place over many thousands of years. This one (if it happens) will take place in a mere 100 or so years. Animals and people can adapt slowly to gradual changes, but abrupt changes are often disasterous. 2), Modern civilization is not nomadic, and it requires an awful lot of infrastructure. You can't just pick it all up and move to somewhere nicer like you could 3000 years ago. Humanity may survive, but everything we've built may not.

Furthermore, there is increasing evidence that local environmental changes were the death of many ancient civilizations. It's probably not correct to say that climate change didn't cause any harm in the past. If you want to go back further than that, there is evidence that there was a big bottle neck in the human population that was caused by <a href="http://news.bbc.co.uk/1/hi/sci/tech/166869.stm" target="_blank">vocanic winter</a> (however, I don't think that hypothesis is fully accepted -- some say that the last big bottle neck was 2 MYA at the end of the Pleistocene Ice Age). If you want evidence for why rapid climate change has been a Bad Thing in the past, I think there's plenty of it. The two largest mass extinctions in Earth history were both caused by climate change -- at least one of which was precipitated by a meteor strike. The P/T extinction may also have been due to a meteor, but it's also hypothesized that it was caused by a sudden upwelling of oceanic CO2.

Ultimately, it comes down to whether you're willing to take the risk about global warming either not happening or not having negative consequences. As I see it, the mere possibility is enough to warrant trying to prevent it. I would rather waste money on higher energy costs than take a chance on seeing the city I live in be underwater (and it almost is now). It would be too expensive to deal with. Arguments that preventing global warming will ruin our economy are pretty short-sided.

theyeti

Ought Naught

I think that your link is down:

Brian Thompson

Thanks, yeti.

Global temperature is strongly correlated to CO2 levels over Earth history.

Certainly in the distant past when CO2 was 5 or 10 times high than today, the Earth was much warmer eg for 80% of its existence, the Earth has never had polar caps. But what evidence is there at current concentrations of 0.036% or less, it is the major controling or influencing factor in global temperatures?

Unless you want to argue that increased temperatures are causing increased CO2 levels, then I think it's safe to say that the prediction of global warming has been validated by real world data. There is still some uncertainty, though. the question is how much uncertainty are you willing to gamble on.

No, real world data shows at present or historical concentrations of C02 (accepted to have been around 280 part per million or 0.028% of the atmosphere for the last 10,000 years until the 20th century), there is little correlation between CO2 and temperature. Look at those graphs that show temperatures higher than today's for several thousand years during the Holocene Optimum 7000-3000BC or the Little Cimate Optimum 900-1200AD with pre-industrial CO2 levels.

It really comes down to an matter of economics. Even a small increase in flooding or circular storms will cause many billions of dollars in extra damage every year, and many thousands of additional lives lost.

Where is the evidence that the warmer climate of the recent past caused more flooding or storms? Europe experienced some ferocious weather storms during the Little Ice Age of 1300-1850AD eg the storm in 1588 that destroyed the Spanish Armada. During the LIA, it rained less, but because it was cooler, water did not evaporate as fast, leading to the creation of many bogs and swamps and the increased instances of flooding.

Arable land will shift to higher lattitudes,
and lots of people will have to move.

Again, historically this is not supported. Arable land expanded, not shifted. Remember during the Holocene Optimum the Sahara was not a desert and it receive ample rainfall to support vegetation and wildlife. During the LCO, agricultural production boomed (eg grapes were grown in England and Norway), resulting in increased life expectancy and population growth. Some Vikings moved to Iceland and Greenland during the LCO, which were actually able to support human populations relatively easy.

Places that start receiving much more rain will have erosion problems (witness El Nino) and places that receive much less rain will have drought problems. So on and so forth.

Again, show where this has happened in the past when temperatures were persistently warmer for thousands of years, not just extrapolating from a single extreme El Nino event. The principle cause of erosion is vegetative removal and intensive farming practices.

The problem isn't so much that it's causing warming, the problem is that it's going to cause a lot of change that will be extremely expensive to adapt to.

The assumption here is we can engineer a planetary climate system and avoid this predicted warming. If recent warming is solar-forced (the 20th century has seen a very active phase of solar activity, compare the Maunder Minimum of the 17th-18th centuries), then nothing we do on Earth will stop warming. The sun-temperature link is much stronger that the purported CO2-temperature link.

The problem with the evidence you cite is 1) past climate changes for the most part, including glaciations, took place over many thousands of years. This one (if it happens) will take place in a mere 100 or so years.

It did not take thousands of years for the Little Climate Optimum (or the subsequent Little Ice Age 1500-1850AD) to happen. The trend in 20th century warming has not differed from natural variability. Look at those temperature graphs again.

[b]Animals and people can adapt slowly to gradual changes, but abrupt changes are often disasterous. 2), Modern civilization is not nomadic, and it requires an awful lot of infrastructure. You can't just pick it all up and move to somewhere nicer like you could 3000 years ago. Humanity may survive, but everything we've built may not.[b]

The predicted temperature increase from global warming is in the region of 2 degrees C by 2100, correct? Not historically unprecedented. We now have a world economy that generates enough wealth to cover adjustment costs, many magnitudes greater than world GNP thousands of years ago.

Furthermore, there is increasing evidence that local environmental changes were the death of many ancient civilizations. It's probably not correct to say that climate change didn't cause any harm in the past.

No, not "climate change", global warming. Don't change the terms of reference. For example, around 2300BC several Bronze Age civilizations did collapse simultaneously due to rapid climate change - dramatic cooling.

I actually resent it when people bait and switch like this.

If you want to go back further than that, there is evidence that there was a big bottle neck in the human population that was caused by vocanic winter (however, I don't think that hypothesis is fully accepted -- some say that the last big bottle neck was 2 MYA at the end of the Pleistocene Ice Age).

Yes, a volcanic winter or global cooling.

If you want evidence for why rapid climate change has been a Bad Thing in the past, I think there's plenty of it.

No, I did not say "rapid climate change" but "global warming" which is predicted to continue rather steadily.

The two largest mass extinctions in Earth history were both caused by climate change --

Massive cooling.

at least one of which was precipitated by a meteor strike. The P/T extinction may also have been due to a meteor, but it's also hypothesized that it was caused by a sudden upwelling of oceanic CO2.

Yes, it's an interesting theory, but we're talking an instantaneous doubling or tripling of CO2 that was already twice or three times higher in concentration than today. But predicted industrial production of greenhouse gases is not going to match that in scale - from 380ppm nowto maybe 500ppm by 2100, not 4000ppm or 5000ppm.

Ultimately, it comes down to whether you're willing to take the risk about global warming either not happening or not having negative consequences.

This is why I ask for lots of past evidence from known warming periods of detrimental effects.

As I see it, the mere possibility is enough to warrant trying to prevent it.

Not if there is insufficent evidence and you assume of course most of the warming is not only caused by terrestrial rather than external (ie the sun) causes and furthermore most of it is human-caused, not naturally cyclical.

I would rather waste money on higher energy costs than take a chance on seeing the city I live in be underwater (and it almost is now). It would be too expensive to deal with. Arguments that preventing global warming will ruin our economy are pretty short-sided.

If you want to save lives, for the price of one year of Kyoto, you could give eveyone in the Third World clean drinking water.....but that's not the point. What evidence is there that global warming (not generic "climate change") in the recent past was mostly detriment to humans and the environment?

Edited to correct UBB.

[ September 17, 2002: Message edited by: Brian Thompson ]</p>

elwoodblues

Well said, BT. You've obviously done quite a bit of research on this.

theyeti

Wrong. There was major glaciation between 256 and 338 Mya, and more minor, periodic glaciation prior to that up to 544 Mya. Prior to the Cambrian, about 600 Mya, it is thought that there was extensive glaciation covering most of the Earth. ("Snowball Earth".)

See Crowley and Berner, "CO2 and Climate Change" Science 2001 vol. 292 no. 5518 pp. 870-872. Notice especially the chart on page 871 which shows a very strong correlation between past CO2 levels and mean global temperature. (This is over the past 600 My, BTW, and not short term historical changes.) See also the UN <a href="http://www.ipcc.ch/" target="_blank">IPCC</a> report.

This too is wrong. When solar and volcanic effects are taken into consideration, there is a very tight fit between greenhouse gas emissions and observed increases in temperature over that past 150 years. This is why the Intergovernmental Panel on Climate Change (IPCC) released a report in 2001 claiming that greenhouse gasses were most likely responsible for the increase in temperature over the past 50 years. See Science 2001 vol.291 no. 5504 p. 556. See also <a href="http://www.brighton73.freeserve.co.uk/gw/paleo/paleoclimate.htm#100,000years" target="_blank">here</a>, courtesy of our friends at NOAA.

This is also wrong! (Strike three!) Today's temperatures are higher, by about 0.2 oC, than the 900-1200AD warming period. See Jones et al, "The Evolution of Climate Over the Last Millenium", Science 2001 vol. 292 no. 5517 pp.662-7. See also <a href="http://www.ngdc.noaa.gov/paleo/globalwarming/medieval.html" target="_blank">this page from NOAA</a>. Also, <a href="http://www.ngdc.noaa.gov/paleo/globalwarming/paleobefore.html" target="_blank">this page.</a>:
Here's the link to the <a href="http://www.ngdc.noaa.gov/paleo/globalwarming/holocene.html" target="_blank">The So-Called Mid-Holocene "Warm Period"</a>

The Holocene was a period of climatic instability, and caused a lot of problems for cultures living back then. See more below.

The twentieth century has experienced the strongest warming trend of the last 1000 years, by about 0.6 oC per century. At a minimum it will double that in the 21st.

There was no recent period that was warmer, nor one in which there was such a rapid increase, to say nothing of future increases. Given that the premise of your question is wrong, it's hard to answer. (And this applies to most of the rest of your demands to show that past global warming, which did not occur, had some bad consequences. Almost everything else you've written is based on that one very faulty premise, and therefore I will skip most of it.) Anyway, coastal flooding will be caused by increased sea levels due to thermal exapansion of the oceans, and to a lesser extent by melting ice sheets. Coastal flooding is a major problem now, so even a slight increase in sea level will cause billions of dollars in extra damage. Charleston is already almost underwater. As for storms, any time you add extra thermal energy to the Earth's atmosphere, you will increase the number and severity of storms on a global scale, the anecdote that you cite about the English Channel notwithstanding.

For more information about what histrorical climate change has done to civiliazation, see deMenocal "Cultural Responses to Climate Change During the Late Holocene" Science 2001 vol. 292 no. 5517 pp. 667-73. This article is mostly about the effects of drought, which toppled several civiliations, but again this is due to late Holocene climate variation. There is a consistent picture that arises out of all of this, including your anecdotes: sudden climate change = bad.

I was being careless here. The regions which are good for growing will change because some places will recieve more rainfall and others less, among other factors. Read the deMenocal paper cited above. The changes during the Holocene are pretty good evidence for what happens when you start monkeying with global climate.

Huh?

There's no doubt that serious changes in solar output are capable of affecting temperature change more so than CO2. But solar output alone cannot account for the increase in temperature during the 20th century. See the IPCC report. See also the deMenocal paper, particularly this passage:
You mean like this one?


The temperature graphs (the ones in scientific journals -- I'm mistrustful of stuff on the web, but the above is from NOAA) show that warming in the 20th century has been greater than at any other time in the last millenium. Maybe it's a coincidence that this coincides with CO2 emissions. But climate models can't explain the increase based on other variables, like solar output and volcanic activity -- when greenhouse gasses are factored in, the models accurately track temperature change. See the IPCC report.

Quote:

The predicted temperature increase from global warming is in the region of 2 degrees C by 2100, correct?

That's at about the minimum projected increase. The projections range from 1.4 to 5.8 by 2100 (again, see the IPCC report). And it's not as if the rapture will come by 2100 and we won't have to worry about anything that happens after that. Our grandchildren will still be living by then.
This completely misses the point. Many thousands of years ago, people were almost exclusively nomadic. They simply moved to places that had better conditions (or they died). We can't do that today. The histrorical and paleoclimatic evidence shows quite clearly that several ancient civilizations, including the Akkadian, Mayan, Mochica, and Tiwanau, colapsed due to climate change, even though nomadic hunter-gatherers were able to adapt. Can you imagine trying to move New York someplace inland, or moving the American midwestern farmers up to Canada? It's just great that we have more wealth today than we did back then, but it we want to keep it, we shouldn't screw with global climate. We will of course survive. We'll just be a lot poorer for it.
So is your argument that gobal warming won't cause climate change? Everything remains just the same? I must admit that's a first.

Poor baby.

No, it's predicted to accelerate to at least twice as fast as the last century, which was already the fastest of the last millenium. This will cause relatively rapid climate change. You are living under a rock if you think otherwise.

<a href="http://news.bbc.co.uk/1/hi/sci/tech/2038599.stm" target="_blank">Nope</a>.

"Instantaneous" means many hundreds or thousands of years on a geological scale. Probably less of a time frame than human caused release of greenhouse gases.

Sorry Bubba, but there is sufficient evidence.

theyeti

[ September 18, 2002: Message edited by: theyeti ]</p>

elwoodblues

A quick word on the graph above...

I've encountered this graph before (or one that looked astonishingly like it). From what I could tell, it didn't take into account the growing black-top heat-islands of cities (which skew the results towards the high end the more developed the planet gets). This would certainly account for why the rise in greenhouse gases seems to track some sort of temperature increase.

Certainly, greenhouse gas emissions have risen over the last century. So have city heat-islands. One of these could be creating the hockey-stick-like graph above. Heat-island growth and greenhouse emissions are pretty closely linked; it'd be easy to mistake skewing effects of one for true causation from the other.

S2Focus

Do you really believe that climatologists worldwide have failed to account for the "heat island" effect?

It should be pointed out that the warming has been most dramatically pronounced at the the high latitudes (Alaska, Siberia, etc.). Not much "heat island" impact there.

In addition, the oceans are now showing a global-warming signature. The Atlantic, Pacific, and Indian Oceans have undergone a net warming since the 50's and 60's. The lost city of Atlantis notwithstanding, I rather doubt that urban heat-island effects are much of a factor here.

This "heat island" argument put forth by global-warming deniers is eerily similar to some of the arguments against radiometric dating put forth by creationists.

(edited to fix a grammatical "thinko")

[ September 18, 2002: Message edited by: S2Focus ]</p>

elwoodblues

I've seen it happen before.

We're talking about very serious, drastic actions. I want serious, definite proof. I've seen climatologists fail to account for heat island effects; that's where many of the most catastrophic predictions came from in the 70's and early 80's. I've also seen them not accounting for it recently, as well, as recently as the last few years. It's a legitimate concern.

This is something that hasn't really been brought up yet. People say global warming and they imagine deserts getting hotter, temperate zones becoming deserts. They don't imagine Alaska getting warmer (which IS where most of the global warming effects should take place; in the coldest places, and mostly at night). A good piece of PR on the part of environmentalists there. There is the possibility that this might be a good thing, warming up the coldest places a little? Makes them a touch more habitable, a touch more arable, the growing seasons a touch longer.