Nature - Urban Heat Island Effect Debunked

[hatrack]

"A major argument used by sceptics of global warming is flawed, a UK Met Office study in Nature magazine says. This argument maintains that much recorded climate data is inherently unreliable because of where weather instruments are situated.

Most are in or near cities, which produce their own heat; so the rapid warming measured over the last century could be just a record of urbanisation. The Met Office believes its study shows this "urban heat island" idea is wrong.

The analysis has been done by Dr David Parker. He used data for the last 50 years to create two separate graphs. One plots temperatures observed on calm nights, the other on windy nights. If the urban heat island hypothesis is correct, he says, instruments should have recorded a bigger temperature rise for calm nights than for windy ones - because wind blows excess heat away from cities and away from the measuring instruments. But there is no difference between the curves. "It helps to answer the critics," Dr Parker told BBC News.

"There are other kinds of temperature measurements, too, which could not be influenced by urbanisation, such as warming in the oceans. "Different methods of measurement can produce different rates of warming but they all point upwards." Myles Allen, from the atmospheric physics department at Oxford University, agrees: "It's pretty convincing," he said. "It's a sensible analysis which tests a prediction of the sceptical theory; and if it's right, we should see a greater effect on calm nights. "But you should never overestimate the ingenuity of the sceptics to come up with a counter-argument."

EDIT

http://news.bbc.co.uk/1/hi/uk/4021197.stm

[On the Road]

1. That's Great

I had heard the urban heat island explanation before, and it seemed like an interesting hypothesis to explain some of the results. Unfortunately, it was seized on as a way to discredit all gobal warming data. These red herrings are used as a way to forestall action indefinitely.

[NMDemDist2]

2. i live on the outskirts of Phoenix (or it was the outskirts 8 years ago)

and on summer nights after midnight we could pass a certain street where the urban density started to thin out and feel an immediate 10 degree temp drop in the convertible car

urban heat sinks aren't a "theory" here.....

[petronius]

3. I don't think the article (which I haven't read yet)

is debunking the idea of the heat island itself. Heat islands definitely exist at the local scale. Rather, I think the article is debunking the argument that heat island effects have a strong enough impact on the overall instrumental record to be responsible for the observed global-scale warming trend...