In a story today in the Los Angeles Times entitled “To slow global warming, install white roofs,”
author Margot Roosevelt reports on a recent study that concludes, if
you take it at face value, that all we have to do is paint all of
our urban rooftops and pavements white and “the global cooling effect
would be massive.”
“According to Hashem Akbari, a physicist
with the Lawrence Berkeley National Laboratory, a 1,000-square-foot
roof — the average size on an American home — offsets 10 metric tons of
planet-heating carbon dioxide emissions in the atmosphere if
dark-colored shingles or coatings are replaced with white material…
Globally, roofs account for 25% of the surface of most cities, and
pavement accounts for about 35%. If all were switched to reflective
material in 100 major urban areas, it would offset 44 metric gigatons
of greenhouse gases.”
It would be interesting to understand exactly
what Akbari means by this. Is this 44 metric gigatons per year? If
not, over what period of time would reflective roofs collectively
offset these 44 gigatons? Considering all the nations of the world
combined are still emitting somewhat less than 30 gigatons per
year, this is a very impressive statistic, no matter how you slice it.
Dr. Akbari’s study isn’t what one should
necessarily question, however. We have always insisted the role of
land use changes are greatly underestimated when assessing regional
climate trends; from tropical deforestation to enhanced thermal
absorption due to aquifer depletion to urban heat islands. More
pertinent is why the role of urban heat islands - dismissed by the
press as a Crichtonian fabrication - has never had credibility, but
suddenly the global cooling potential of urban cold islands is cause to
legislate? Read the IPCC’s 4th Summary for Policymakers
(watch out, it’s 3.6 MB) - you will note the role of land use in
causing global warming is minimized, and the role of urban heat islands
is negligible. Can you have it both ways?
Another interesting paradox here is the
following statement from the report ”Globally, roofs account for 25% of
the surface of most cities, and pavement accounts for about 35%.” Well
maybe if we let people have yards again instead of cramming them into
cluster homes, there would be enough land for people to plant trees and
create an urban canopy. And if our cars are all soon to run on wind
and solar power, maybe we should quit trying to force people out of
them and into government operated light rail, busses, and “jitneys.”
The real take-away here is, once again, that
there is very little certainty regarding the causes, the severity, or
even the direction of climate change. The rhetoric and the
conventional wisdom is way behind the latest science and observational
data. The policymakers and pundits who have ridiculed the notion of an
urban heat island are the same people who are uncritically reporting we
must now make every road and roof reflective to mitigate this heat
island. There’s nothing wrong with making rooftops reflective to save
energy - but does every sensible green product have to
incorporate avoiding doomsday in their marketing and lobbying strategy?
Climate change is not a trivial issue. Concern
about climate change is nothing to be mocked. But if you removed from
the alarmist coalition the people who condone this alarm because they
like the side effects - bigger government, more funds for environmental
groups, nonprofits and academia, more taxes so the public
sector can avoid fiscal reform, more subsidies and regulations so large
corporations can crush emerging corporations, and greater energy
independence - the only good side effect on that list - you aren’t left
with much. At the least, journalists and scientists should recover
their innate skepticism, the lifeblood of their professions, and
not abdicate their responsibility to point out this contradiction - the
IPCC dismisses the heat island effect, yet today’s latest scientific
study claims if we made our cities reflective “the global cooling
effect would be massive.”
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