From Roger Pielke Sr.
A very good news article titled Expanding cities contribute to global warming by Doyle Rice has been published on USA Today.
The article is based on our paper
Fall, S., D. Niyogi, A. Gluhovsky, R. A. Pielke Sr., E. Kalnay, and G. Rochon, 2009: Impacts of land use land cover on temperature trends over the continental United States: Assessment using the North American Regional Reanalysis. Int. J. Climatol., DOI: 10.1002/joc.1996.
The USA Today article reads
The USA’s expanding cities and suburbs are contributing more to global warming than previously thought, says a new study in the Royal Meteorological Society’s International Journal of Climatology.
“We found that most land-use changes, especially urbanization, result in warming,” said study co-author Eugenia Kalnay of the University of Maryland.
Most scientists believe man-made climate change is primarily the result of increasing concentrations of carbon dioxide (CO2) and other greenhouse gases into the atmosphere. So, does this mean rising temperatures due to greenhouse gases are less significant? No, say study authors.
“I think that greenhouse warming is incredibly important, but land use should not be neglected,” Kalnay said. “It clearly contributes to warming, especially in urban and arid areas.”
As for how much it contributes, compared to greenhouse gases, “we cannot provide a specific percentage,” writes study co-author Roger Pielke, Sr., of the University of Colorado in an e-mail. “But our results suggest that land-use change can affect surface temperatures as much or more than what has been simulated by the global climate models as being due to added CO2 from human activities.”
The study recommends that the predicted land-use changes be incorporated into the computer models designed to forecast changes in climate conditions. This is key, according to study co-author Dev Niyogi of Purdue University. He said that even with aggressive green emission controls, warming will still continue unless how we use the land is considered.
“Continued temperature changes will occur as long as the landscape continues to be altered,” added Pielke. “The subject of the effect of future land use change on local and regional climate should be a major focus of upcoming climate assessments.”
Among the study’s findings:
– Land use conversion more often results in warming than cooling.
– Urbanization and conversion to bare soils have the largest warming impacts.
– Conversion to agriculture results in cooling, while conversion from agriculture generally results in warming.
– In general, the more the vegetation covers an area of land, the cooler its contribution to surface temperature.
– Deforestation generally results in warming, with the exception of a shift from forest to agriculture
– The temperature effect of planting a new forest is unclear.
Latent heat (and convection) is good at the surface (where it’s needed) for half to a third of the total energy leaving. It seems to practically disappear by tropopause altitude (where it’s not needed).
I’m forever amazed at the confusing between local effect, UHI, and global effect which goes on. Earth is 70% ocean which dominates the albedo – so far as the surface is concerned. What’s more, the atmosphere (primarily clouds) is responsible for 0.22 of the 0.30 albedo – meaning that the surface supplies only 0.08 of the total. Applied as an average, overall the surface supplies about 27w/m^2 worth of albedo reflected power. The mix of surface albedo is a combination between oceans, with 0.04 or less albedo at 70% of the total contribution and land at 30% contribution which is providing (without doing the math this morning) something between 0.1 to 0.2 for its average contribution.
I can’t wait until someone figures in the total power solution of the world’s energy by using classical solar panels. I think they’ve got something like a 0.02 albedo and an efficiency of under 10% conversion to energy. Those panels with higher efficiency use light concentration techniques. The size of such panel systems actually might become a problem – if it were possible to build such a thing.
In the context of alarmism, UHI is a powerful effect that will contribute to our heat death.
But in the context of the effect of UHI on temperature measurements, UHI is insignificant and can be dismissed.
Perhaps the alarmists should get their story straight….
Chris
So land use is having more of an effect on global warming than previously thought AND rising temperatures due to green house gases are not less significant. I’m confused.
“I think that greenhouse warming is incredibly important, but land use should not be neglected,” Kalnay said.
Absolutely, hundreds of thousands of peoples livelihood (people like Kalnay) depend on the gravy train of Global Warming Hysteria.
Hundreds of millions of tax payers are paying for it.
Millions stand to lose their jobs as the West further curtails all industrial activity in favor of lower cost production overseas.
It is all INCREDIBLY IMPORTANT.
After leaving church yesterday at noon and at 8 pm, the temp reading in my car dropped 5-6 degrees. The country is cooler for several reasons. We sure do not see them adding weather stations in the country and eliminating city locations.
“In addition a general lowering of ground water will lessen the cooling effect of evaporation.”
Irrigation.
Irrigation can lower daytime highs due to evaporation but can increase nighttime lows due to increased humidity. I also saw something recently that I can not locate right now that said the UN had to back off of their global deforestation numbers because they came to notice that there has been a significant reforestation in North America and Europe and the net reduction in forest globally turns out to be much less than they had been saying. Nobody took into account the increase in trees in the Northern Hemisphere before.
“We sure do not see them adding weather stations in the country”
That is a major issue. Huge numbers of rural reporting stations have been removed from the land-based temperature databases recently.
“The Time Machine” story makes sense now. In the distant future the AGW believers will become the underground-dwelling Morlocks, while the deniers will become the Eloy.
So just how is this a “good news” story? Are we going to ward off dangerous warming by plowing under our cities?
Pat Moffitt (06:01:38) :
So land use is having more of an effect on global warming than previously thought AND rising temperatures due to green house gases are not less significant. I’m confused.
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It’s a positive feedback that we’re already familiar with; the revelation that CH4 warms “more than we thought” does not mean that CO2 warms less than we thought. The overall warming increases invisibly, since the additional heat slides into the “as much as 30 years of cooling” pipeline. If, when it emerges, the sun happens to be particularly active, it will be worse than we thought, although the sun doesn’t actually have any impact on climate change.
Is it really clear that agriculture warms or cools? There’s an enormous variability in the circumstances of agricuture around the world. You won’t see thousands of square miles of irrigation across the prairie wheatfields and the transpiration of foliage is very different in the early stages of growth, compared with at its peak.
The photo above is of Horsethief Canyon Ranch(a Corona zipcode but outside the city) and I can attest to the fact that it is a lot warmer in the asphalt parking lot of the school in the upper left side of the photo than in the grass playing field! My church meets in that school! Lurker for several years and very surprised to see my home turf!
Bruce Cobb – My thoughts exactly .
Well when you erect efficient energy absorbers and RADIATORS in these urban locations, and then measure the temperatures in the same locations; you would expect the LOCAL temperatures to go up.
That is a far cry from having the global mean temperatures go up; you know; all those vast areas where they don’t measure the temperatures.
Why are they building all of these cities and suburbs anyway. I would have thought that we had more than enough cities to absorb all the politicians available in the world to serve as Mayors and city councilpersons.
Must be something else going on that we don’t know about to cause all these extra cities and suburbs to get built; maybe some sort of new craze.
George E. Smith (10:41:58) :
“Must be something else going on that we don’t know about to cause all these extra cities and suburbs to get built; maybe some sort of new craze.”
It’s called a housing bubble. Many of the same folk who are so determined to cap and trade were also so insistant that easy credit make it possible for people who couldn’t afford them, to buy houses, in Chino, Chico, and other parts of the Inland Empire. Many of these houses are empty, with large numbers threatening to become so – not to fear – The Government is here to help.
I remember the first time I ran into one of the new products of the American Educational System – I was studying Physics in Zurich, and a newly minted post-Doc from Stanford showed up. The phrase “not relevant” kept popping up when discussing certain aspects of hard science – I didn’t understand it then, I still don’t, but I can see what we’re harvesting.
barackalypse,
the time machine novel was an interesting novel with an interesting warning. The eloy were the brain dead, dumbed down food source for the industrious, hardworking subteranian morlocks. Actually, for HG Wells, the eloy were the descendents of the useless aristocracy, degenerated to animal.
There are only 3 cards I am moving around. Just find the lady, and win.