Posted on 12/23/2003 12:33:31 PM PST by cogitator
Edited on 04/13/2004 2:45:19 AM PDT by Jim Robinson. [history]
The fossils of palm trees are not from "centuries" before the Industrial Revolution; they are from millions of years before the Industrial Revolution. Earth has had much warmer, and much colder, periods than present, if you want to examine the geological record. But you can't compare then to now, because for one thing, the continents weren't even in the same place.
No, I don't know that. What I know is that the 20th century had three major temperature-trend periods; 1900-1940, with about a 0.3 C warming (and a recent paper indicates that solar variability contributed substantially to this warming); 1940-1980, with about a 0.2 C cooling; 1980-now, with about a 0.8 C warming. (Adds up to about 0.7 C; we've added about 0.1 C since 2000). It's the last 25 years that is really starting to look unusual -- and that's not model-based.
This is a paraphrase, not a quote. The quote doesn't say this. Some of my friends, meteorological scientists, don't talk like this but concern themselves with data and mathematical models. You want Reynolds numbers and Bournoulli cells, fine, but otherwise don't waste precious time gabbing. Dragging scientists into the politics is probably impossible and just annoys them.
Although the vast majority of climate researchers are persuaded by the offer of government grants to agree that the evidence and models show global warming is real, a few scientists have refused to feed at the trough of the government and state that there is no convincing evidence and models which can't be trusted for two weeks are being used to make implications about changes on a geologic time scale.
Wouldn't that have been a better way for them to report this?
Why the cooling between 1940-1980? It makes no sense if CO2 is the major driver. There are ups and downs in tempreture, similar to a sine wave. To pick the low end (after the 0.2 cooling) and take the high end now is minipulating the data. The 40 years of cooling doesn't make sense if CO2 is the major culprit. The so-called rapid increase is much more likely a correction. I see a slight warming trend in the long-term (with both natural and man-made causes), and the 20-year of 'rapid increase' was more a result of the previous cooling than a significant indicator that the overal warming trend is accellerating. To pick a stastically insignificant 20-year period and using that as your new curve is stipid unless you are a fear-mongering global warmer pushing some agenda.
But, if memory serves, it still isn't nearly as warm as 1000 years or so ago.
Temperature changes over the millenia, even before any possible human contribution has been far larger, yet no one knows for certian what caused it. Until they can explain the reason for the historicly larger changes, then they don't know squat about how man might be affecting those natural changes in climate.
It's like we've observed the ocean for an hour, and then saying we know we can make a wave on the ocean, so therefore we must be causing the tide.
That's because I peed there!
I think I am getting on, but you are by any measure OLD.
Even so, the latitudes of the various continents have not changed that much, have they? (It is my understanding that the continental drifts, if they occurred, have been mostly east-west and not north-south.) My point is that the earth warms and cools cyclically in spite of human activity.
But that's doesn't represent the entire chemistry of a tree. Once photosynthesis has occured to store solar energy, that stored energy is used which will release some CO2. Furthermore, what gases do trees release at night when no photosynthesis can occur?
Evidence?
Regarding continental movements, it depends on how far back you go in paleohistory. At one interesting time, all of the continental plates were clustered down at the South Pole! As for your point, it's quite true; the main problem is that natural cycles (most of the time) operate at much longer time-scales that for the current observed temperature change. And there have been times of abrupt climate change when things change even faster -- one concern of some of the climate scientists is that we could be "pushing" the climate system toward an abrupt change tipping point, which would lead to unpredictable, drastic consequences.
One possibility is that earth's climate would suddenly change to a state outwardly identical to what we have now. Everything would be different, yet we wouldn't notice.
Scientists have assumed that global warming would speed evaporation in parts of the world's oceans but had no direct way of measuring the change. In the Woods Hole study, published in the journal Nature, scientists estimated that tropical evaporation rates increased 10 percent during the last 15 years.
Oh dear, seems to be in conflict with another study saying things quite different on a global basis:
Solar Radiation Reductions at Earth's surface:
http://www.co2science.org/journal/2001/v4n49c2.htm (Dec 2001)
http://www.co2science.org/edit/v6_edit/v6n32edit.htm (Aug 2003)
http://www.guardian.co.uk/life/feature/story/0,13026,1108853,00.html (Dec 2003)
Surface solar radiation revealed an estimated 7W/m2 or 4% decline at sites worldwide from 1961 to 1990. Here I find that the strongest declines occurred in the United States sites with 19W/m2 or 10%. The clear sky optical thickness effect accounts for -8 W/m2 and the cloud optical thickness effect for -18 W/m2 in three decades. If the observed increases in cloud cover frequencies are added to the clear sky and cloud optical thickness effect, the higher all sky reduction in solar radiation in the United States can be explained. It is shown that solar radiation declined below cloud-free sky because of the reduction of the cloud-free fraction of the sky itself and because of the reduction of clear sky optical thickness. Solar radiation exhibits no significant changes below cloud-covered sky because reduced cloud optical thickness is compensated by increased frequencies of hours with overcast skies
Sulfate aerosols (there was a marked increase in industrial activity post WWII, and not a lot of emissions controls!) On the "Rushing to Judgment" thread, I posted a summary of the paper "Do Models Underestimate the Solar Contribution to Recent Climate Change?" paper just published in Journal of Climate. Quote from Introduction: "Coupled model simulations show that warming over the last 50 yr can be explained by a combination of greenhouse warming balanced by cooling from sulfate aerosols." There was also a decently large eruption in 1963 (Agung) that may have helped out a bit.
It's always possible to reduce or augment a "signal" by an "astute" choice of baseline (i.e., depending on what mean you compare to), but if you look at the trends decade-by-decade, these trends emerge. The data is not being manipulated in this circumstance. Even if the starting point was chosen before the 1940-1980 cooling period, it's warmed up 0.5 C over that point since the mid-80s.
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