QUESTION about global warming

The idea is correct, but this bias has been known and taken into account for at least a couple of decades. So, I'm afraid you can't explain away global warming that easily.

The Temperature charts I've seen posted never have an (*) at the bottom saying the temp's have been adjusted for the heat island effect. How much temperature variance does this effect cause? Does anyone have a good site to visit in order to learn more?

Good. Scientific questions are not matters of faith in the first place. As for your other questions, you can start here: http://www.autobahn.mb.ca/~het/globalwarming.html

<l8r>

They probably don't have a footnote describing all other factors you have to take into account either. If they did it would be more of an article than a footnote. You will have to go to the original articles to find detailed descriptions of how to derive a temperature trend from the available data.

Not much. It's noticable but even with no corrections at all it is not enough to explain away global warming. And then there are other temperature sets that can't possibly be affected by heat islands, such as those derived by drilling a deep hole and measuring the temperature profile, taking into account that it takes a certain amount of time for heat to propagate to a certain depth.

Do a search in google in sci.environment for 'heat island'. The issue has been discussed lots of times before.
http://www.autobahn.mb.ca/~het/globalwarming.html Has lots of links to information about global warming. It's always a good place to start, or you could go to the IPCC report.

Complete nonsense. The Urban Heat Island effect is a systematic error with a variation of anything up to 8C. It cannot be 'accounted' for as it has first to be calibrated with what the temperature would be without the concrete, airconditioning and traffic. Since its also variable for both seasons and on a daily basis, it produces an error too large to be accounted for.

The UHI totally swamps the long term temperature trend (20th century warming 0.6C). The only way around it is to retrend the data in favour of rural stations or ignore them altogether.

How do you do that? Does it get colder as you get deeper?

That doesn't mean any conclusion has been reached, or any knowledge

Absolutely correct, Titan, you're posting complete nonsense. The issue is NOT about whether urban environments are warmer than rural, but rather the CHANGE that has taken place in those environments. It can and is accounted for, Titan. Try again. While you're at it, could you please explain why the following papers found a negligible difference in global temperatures when urban and rural records were separated?

Owen, T. W., K. P. Gallo, C. D. Elvidge, and K. E. Baugh, 1998. Using DMSPOLS light frequency data to categorize urban environments associated with U.S. climate observing stations. Intl. J. Remote Sensing 19, 3451-3456.

Peterson, T. C., and R. S. Vose, 1997. An overview of the Global Historical Climatology Network temperature database. Bull. Amer. Meteorol. Soc. 78, 2837-2849.

Another lie, Titan, but, hey, what's one more to add to the long list you're building.

Do some reading:

Then you'd better publish this, as there are lot of scientific articles in print which do account for it.

And you've published this revelation in which journal?