IPCC report on global warming, and what to do about it
I read the Working Group 1 IPCC summary report on climate change.
http://www.ipcc.ch/SPM2feb07.pdf
It seems to pretty definitively say that global warming is occurring, that it is caused by human actions (burning fossil fuels, agriculture, etc), that it will cause sea levels to rise, and probably more flash floods, heat waves, hurricanes, etc.
One thing that struck me was the relatively small amount of "radiative forcing" involved. Which is to say that the total effect of (current) anthropogenic global warming is about 1.6 watts per square meter.
By comparison, full equatorial noon sunlight is 1000 watts per square meter. So if we could cover .0016 of the earth's surface (1.8 million square kilometers, about the size of Texas) in reflective aluminum foil, it would approximately zero out the net temperature rise. It would probably be best to cover an area of ocean instead, since water reflects less solar energy than land, and you don't have to cover anybody's lawn.
Hypothetically assuming aluminum foil 0.1 mm thick, we'd need a chunk of aluminum a kilometer across and 180 meters high, weighing 540 million tons. Oops. Better multiply that by three, since any given spot on the equator won't always be in sunlight. Right now industry worldwide only produces ~30 million tons of aluminum a year, total, so it doesn't seem feasible.
Turning an area ten times the size of Texas from forest to desert could also work, since sand reflects light better than trees, but the side effects would be nasty, to say the least.
Ice reflects sunlight really, really well. And it's cheap. If we could generate a monster iceberg (or lots and lots of smaller icebergs)... But I can't think of any kind of insulation for the icebergs that would be cheaper per unit area than aluminum foil, and uninsulated icebergs would melt.
How about white flowers? Ideally I want a plant that will grow on the surface of the open ocean, with an albedo (reflectivity) significantly higher than the water it covers.
There are limits. The plant presumably has to photosynthesize, so it has to absorb some sunlight. But according to the albedo link on wikipedia, crops and meadows both have a higher albedo than water, so it's doable. Plant a patch, and let it spread exponentially. The problem of dealing with oceans covered by genetically modified white-speckled water hyacinth is left as an exercise for the student
http://www.ipcc.ch/SPM2feb07.pdf
It seems to pretty definitively say that global warming is occurring, that it is caused by human actions (burning fossil fuels, agriculture, etc), that it will cause sea levels to rise, and probably more flash floods, heat waves, hurricanes, etc.
One thing that struck me was the relatively small amount of "radiative forcing" involved. Which is to say that the total effect of (current) anthropogenic global warming is about 1.6 watts per square meter.
By comparison, full equatorial noon sunlight is 1000 watts per square meter. So if we could cover .0016 of the earth's surface (1.8 million square kilometers, about the size of Texas) in reflective aluminum foil, it would approximately zero out the net temperature rise. It would probably be best to cover an area of ocean instead, since water reflects less solar energy than land, and you don't have to cover anybody's lawn.
Hypothetically assuming aluminum foil 0.1 mm thick, we'd need a chunk of aluminum a kilometer across and 180 meters high, weighing 540 million tons. Oops. Better multiply that by three, since any given spot on the equator won't always be in sunlight. Right now industry worldwide only produces ~30 million tons of aluminum a year, total, so it doesn't seem feasible.
Turning an area ten times the size of Texas from forest to desert could also work, since sand reflects light better than trees, but the side effects would be nasty, to say the least.
Ice reflects sunlight really, really well. And it's cheap. If we could generate a monster iceberg (or lots and lots of smaller icebergs)... But I can't think of any kind of insulation for the icebergs that would be cheaper per unit area than aluminum foil, and uninsulated icebergs would melt.
How about white flowers? Ideally I want a plant that will grow on the surface of the open ocean, with an albedo (reflectivity) significantly higher than the water it covers.
There are limits. The plant presumably has to photosynthesize, so it has to absorb some sunlight. But according to the albedo link on wikipedia, crops and meadows both have a higher albedo than water, so it's doable. Plant a patch, and let it spread exponentially. The problem of dealing with oceans covered by genetically modified white-speckled water hyacinth is left as an exercise for the student