Reply #20

In the discussion thread: Geoengineering would turn blue skies whiter [View all]

Fri Jun 8, 2012, 04:37 PM

20. These approaches are also not effective

Last edited Fri Jun 8, 2012, 05:01 PM USA/ET - Edit history (4)

http://news.stanford.edu/news/2011/october/urban-heat-islands-101911.html

Stanford Report, October 19, 2011
Urban 'heat island' effect is only a small contributor to global warming, and white roofs don't help to solve the problem, say Stanford researchers
Heat emanating from cities – called the "urban heat island" effect – is not a significant contributor to global warming, Stanford researchers have found. They also concluded that if all the roofs in urban areas were painted white, it would increase, not decrease, global warming.

…

One "geoengineering" proposal for reducing the impact of urban heat islands is to paint roofs worldwide a reflective white. Jacobson's computer modeling concluded that white roofs did indeed cool urban surfaces. However, they caused a net global warming, largely because they reduced cloudiness slightly by increasing the stability of the air, thereby reducing the vertical transport of moisture and energy to clouds. In Jacobson's modeling, the reduction in cloudiness allowed more sunlight to reach the surface.

The increased sunlight reflected back into the atmosphere by white roofs in turn increased absorption of light by dark pollutants such as black carbon, which further increased heating of the atmosphere.

Jacobson's study did not examine one potential benefit of white roofs – a reduced demand for electricity to run air conditioning in hot weather. But a recent study done at the National Center for Atmospheric Research showed that the decrease in air conditioning use, which occurs mostly in the summer, might be more than offset by increases in heating during winter months.

"There does not seem to be a benefit from investing in white roofs," said Jacobson. "The most important thing is to reduce emissions of the pollutants that contribute to global warming."

…

http://www.democraticunderground.com/discuss/duboard.php?az=show_mesg&forum=115&topic_id=314310&mesg_id=314310

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Replies to this discussion thread

29 replies	Author	Time	Post
Geoengineering would turn blue skies whiter [View all]	joshcryer	Jun 2012	OP
Geoengineering experiment cancelled amid patent row	joshcryer	Jun 2012	#1
A charter for geoengineering	joshcryer	Jun 2012	#2
... and I've been there with you ...	Nihil	Jun 2012	#14
+1	drokhole	Jun 2012	#15
From 7 years ago	dipsydoodle	Jun 2012	#3
Nobody actually needs to SEE the stars. That's what we have satellites for...	GliderGuider	Jun 2012	#4
I'm not sure resort is the right word	The2ndWheel	Jun 2012	#5
Mind you, this is just one scenario. (i.e. adding sufates to the upper atmosphere.)	OKIsItJustMe	Jun 2012	#6
Other schemes are not cheap. Global dimming happens for free* when you pollute.	joshcryer	Jun 2012	#18
Even this scheme actually involves some expense	OKIsItJustMe	Jun 2012	#19
I didn't say it was free, I said it was cheaper than the alternatives.	joshcryer	Jun 2012	#23
"Global dimming happens for free* when you pollute."	OKIsItJustMe	Jun 2012	#24
Did you not see the asterisk?	joshcryer	Jun 2012	#25
Sure did!	OKIsItJustMe	Jun 2012	#28
Jevon's Paradox would be a useful parable here.	IDemo	Jun 2012	#7
I am tired of “Jevons’ Paradox”	OKIsItJustMe	Jun 2012	#9
Then we're disagreed on the issue	IDemo	Jun 2012	#10
In the first place, this is a misapplication of “Jervons Paradox”	OKIsItJustMe	Jun 2012	#11
You must have missed the word "parable" in my post	IDemo	Jun 2012	#12
Jervons was wrong	OKIsItJustMe	Jun 2012	#13
Never mind aesthetics	caraher	Jun 2012	#8
What Are People Really Talking About When They Talk About "Geo-Engineering"?	drokhole	Jun 2012	#16
Aerosols are the cheapest way to do it, and thus is how it is going to be done.	joshcryer	Jun 2012	#17
These approaches are also not effective	OKIsItJustMe	Jun 2012	#20
Reducing incoming sunlight does not help with ocean acidification,	drm604	Jun 2012	#21
Correct!	OKIsItJustMe	Jun 2012	#22
Nothing to see here...	joshcryer	Jun 2012	#26
It's not that there’s nothing to see here	OKIsItJustMe	Jun 2012	#27
Scientists warn geoengineering may disrupt rainfall	joshcryer	Jul 2012	#29

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