US Energy Secretary Steven Chu, one of the world’s greatest minds, believes painting roofs, roads and pavements white will help contain global warming. Reader Steve H. reviews the Chu plan:
According to a 2004 study by the U.S. Geophysical Union, all constructed so-called “impervious surfaces” (buildings, roads, parking lots, roofs, etc.) in the USA total a combined 112,610 km^2. Which is a bit less than the total area of Ohio, a bit more than Virginia.
That means we’ve got about 1.14% for Dr. Chu to paint.
That should make a big difference.
Vast coverage of the planet by human construction is a common assumption among greenoids, who evidently imagine that their own surrounds are a universal global standard.
Hmm, let’s do a quick check
the RF for a doubling of CO2 is likely 3.7Â±0.4 W/m2 – the same order of magnitude as an increase of solar forcing by 2%.
So changing the albedo of 1% of the Earth’s surface from 0 to 1 would negate 50% of the forcing from doubling CO2. Of course, the real change in albedo is somewhat less, and we can only do this on land, but it seems clear that changing the albedo of even a relatively small area will make a difference.
If you check the paper that Chu was referring to, you’ll discover that far from assuming “vast coverage of the planet by human construction”,
We estimate that urban areas are at least 1% of the Earth’s land area or about 1.5×10^12 m^2 (see Table 5). The roof area is 3.8×10^11 m^2. The paved surface area is
5.3×10^11 m2. We calculate a global RF of -4.4×10^-2 W/m^2 by cool roofs and cool
pavements.We then estimate the global emitted CO2 offset potentials for cool roofs
and cool pavements to be in the range of 24 Gt of CO2 and 20Gt of CO2, respectively,
giving a total global emitted CO2 offset potential range of 44 Gt of CO2. This 44 Gt CO2 offset is over 1 year of the 2025 projected world-wide emission of 37 Gt of CO2