GeologyRocksglobal warming
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Re: global warming
Tue, 09/27/2005 - 08:10Who believes it? I don't. I think the earth's temp has been fluctuating for as long as it has existed, and for us to say we have definitely been having an affect on it in the last 15 years with our SUV's or whatever else, doesn't hold much.
I'm semi-convinced. The Earth has had some pretty spectacular climatic changes in the past and some have been very rapid. However, this change in temperature starts around the Industrial Revolution (when we started burning a lot of coal, wihtout and scrubbing, environmental considerations, etc) and looks to be far too rapid. However, it could be a blip on the climatic signal and we could have a few years of rapid cooling. Unfortunately, climate change is one of those things where you can predict all you like, but you'll never know until it happens and by that time it's too late...
BTW, most scientists call it "anthropogenic climate change" rather than global warming. The anthroprogenic indicates the man-cause component and the change is because some parts of the globe may get cooler. The climate is chaotic after all...
One scientist has been measuring the temp of the earth from 43 feet below the surface for the last 40 years, whereas most others measure it from right above ground. he's found that the temp has been increasing, and that at this depth the temperature wouldn't be affected by summer warming. He says this is an indication of global warming. But I wonder, if he just said this is a depth not affected by summer warming, wouldn't that mean that the outside temperature doesn't really have an affect on it so it really wouldn't be an indicator of that? And that the temperature increase could in fact be coming from the center of the earth and an increase in radioactivity in the core?
The summer changes in temperature can only penetrate a few metres into the ground due to the dissipation of heat - as soon as the source of heat is removed (summer heat), the temperature will start to drop. You can prove this relatively easily using the basic heat equation and a bit of maths. The outside temperature does have an effect, but it is very small and the deeper you go, the long the heat source most be there in order to raise temperature. The scientist in question would have done some maths, found out that 43 feet is the optimum depth for measuring temperature change over x years without getting the short term variations (summer, winter, etc).
The temperature increase could be coming from the centre of the Earth, but not due to an increase in radioactivity, as that can only decrease over time (unless you put more in), but the rate of change inthe signal would be much, much slower than a change caused by climatic changes.
Wow - bit of a long post there!
Jon
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global warming
Tue, 09/27/2005 - 19:35I'd agree. There probably is global warming taking place, but other than a very small part played by man I think it is simply a natural cycle. Didn't we have it drummed into us that the key to the past lies in the present.
There has to be an element here of not knowing how quickly changes happened in the past. No doubt in time paleoclimatologists will be able get more and more accurate with this, but I think we are assuming changes happened more slowly in the past, and perhaps the big ones did. But did they, or are we witnessing a mini change now with a greater one still to come?
Another factor is that pre-man there was no one to worry about coastal erosion, oceanic transgression, ice sheets melting, changes in vegetation etc.
Now man 'owns' bits of the planet he feels he ought to do something to stop this!
(gets down off his soap box) :oops: John
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Tue, 10/04/2005 - 12:20I think global warming's a combination of natural with human acceleration. At the moment my greatest concern is the catastrophic decline in breeding seabirds around Britain's coasts, particularly those that depend on sand eels (like kittiwakes and guillemots). Global warming is being blamed in ornithological circles since the fish have moved far to the north. To give some idea of the extent of the problem, in 1995 kittiwakes raised over 5,000 chicks at Bempton Cliffs (Yorks), this year not a single chick fledged.
Gus
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Wed, 10/05/2005 - 08:39Just a quick thought (not an original one by me, but proposed by a few people in New Scientist recently) - what if, as some people have suggested, ice sheet melting is not due to global warming, but a global drying - http://www.newscientist.com/channel/earth/mg18725141.500
Glacial melting on Kilimanjaro (which some people have proposed as evidence for global warming) may not be related to warming at all, just a lack of precipitation...
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Wed, 10/05/2005 - 15:06so global drying would mean what, that there is less water in the air, more in oceans and things? What other impacts could this have?
But just how much more water would this be? seems like the amount of water turned into vapor wouldn't effect the levels of the oceans that much.
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Submitted by KU40 on Tue, 09/27/2005 - 04:46.Who believes it? I don't. I think the earth's temp has been fluctuating for as long as it has existed, and for us to say we have definitely been having an affect on it in the last 15 years with our SUV's or whatever else, doesn't hold much.
One scientist has been measuring the temp of the earth from 43 feet below the surface for the last 40 years, whereas most others measure it from right above ground. he's found that the temp has been increasing, and that at this depth the temperature wouldn't be affected by summer warming. He says this is an indication of global warming. But I wonder, if he just said this is a depth not affected by summer warming, wouldn't that mean that the outside temperature doesn't really have an affect on it so it really wouldn't be an indicator of that? And that the temperature increase could in fact be coming from the center of the earth and an increase in radioactivity in the core?
I'll have another question in the non-conventional ideas forum.