GREGORY BENFORD is a physicist at the University of California at Irvine and a novelist. His latest novel is Beyond Infinity.
Few economists expect the Kyoto accords to attain their goals. With compliance coming only slowly and with three big holdouts—the United States, China, and India—it seems unlikely to make much difference in overall carbon dioxide increases. Yet all the political pressure is on lessening our fossil fuel burning in the face of fast rising demand. This pits the industrial powers against the legitimate economic aspirations of the developing world—a recipe for conflict.
Those who embrace the reality of global climate change generally insist that there is only one way out of the greenhouse effect: Burn less fossil fuel, or else! Never mind the economic consequences. But the planet itself modulates its atmosphere through several tricks, and we have tended to ignore most of them. The global problem is simple to explain: We capture more heat from the sun than we radiate away. Mostly this is a good thing; otherwise the mean planetary temperature would hover around freezing. But recent human alterations of the atmosphere have resulted in too much of a good thing.
Two methods are getting little attention: sequestering carbon from the air and reflecting sunlight.
Hide the Carbon
Inevitably, we must understand and control the atmosphere, as part of a grand imperative of directing the entire global ecology. There are several schemes to capture carbon dioxide from the air: Promote tree growth, trap carbon dioxide from power plants in exhaust gas domes, or let carbon-rich organic waste fall into the deep oceans. Increasing forestation is a good, though rather limited, step. Capturing carbon dioxide from power plants costs about 30 percent of the plant output, so it’s an economic non-starter. That leaves the third way.
Imagine you are standing in a Kansas field of ripened corn, staring up into a blue summer sky. Imagine the acre around you extending upward, in a transparent air-filled tunnel soaring all the way to space. That long tunnel holds carbon in the form of invisible gas, carbon dioxide—widely implicated in global climate change. But the corn standing as high as an elephant’s eye all around you holds four hundred times as much carbon as there is in man-made carbon dioxide—our villain—in the entire column. Yearly, we manage, through agriculture, far more carbon than is causing our greenhouse dilemma.
Take advantage of that. The leftover corncobs and stalks from our fields can be gathered up, floated down the Mississippi, and dropped into the ocean, sequestering its contained carbon. Below about a kilometer depth, beneath a layer called the thermocline, nothing gets mixed back into the air for a thousand years or more. It’s not a permanent solution, but it would buy us and our descendants time to find better answers. And it is inexpensive; cost matters.
The United States has large crop residues. It has also ignored the Kyoto accords, saying that such measures would cost too much. And so they would, if we relied purely on traditional methods, policing energy use and carbon dioxide emissions. Clinton era estimates of such costs were around $100 billion a year, a politically unacceptable sum that led Congress to reject the very notion by a unanimous vote.
But if the United States simply used its farm waste to “hide” carbon dioxide from our air, complying with Kyoto’s standard would cost about $10 billion a year, with no change whatsoever in energy use. The whole planet could do the same. Sequestering crop leftovers could offset about a third of the carbon we put into our air. The carbon dioxide we add to our air will end up in the oceans anyway, from natural absorption, but not nearly quickly enough to help us.
Reflect Away Sunlight
The planet has maintained its perhaps precarious equilibrium throughout billions of years by editing sunlight with cloud cover. As the oceans warm, water evaporates, forming clouds. These reflect sunlight, reducing the heat below, but just how much depends on cloud thickness, water droplet size, particulate density—a forest of detail.
If our climate starts to vary too much, we could consider deliberately adjusting cloud cover in selected areas to offset unwanted heating. It is not hard to make clouds. Volcanoes and fossil-fuel burning do it all the time, by adding microscopic particles to the air. Cloud cover is a natural mechanism we can augment, and another area where possibility of major change in environmental thinking beckons.
A 1997 U.S. Department of Energy study for Los Angeles showed that planting trees and making blacktop and rooftops lighter colored could significantly cool the city in summer. With minimal costs that get repaid within five years, we can reduce summer midday temperatures by several degrees. This would cut air conditioning costs for the residents, simultaneously lowering energy consumption and lessening the urban heat island effect. Incoming rain clouds would not rise as high above the heat blossom of the city, and so would rain on it less. Instead, clouds would continue inland to drop rain on the rest of Southern California, promoting plant growth. These methods are now under way in Los Angeles, a first experiment.
We can combine this with a cloud-forming strategy. Producing clouds over the tropical oceans is the most effective way to cool the planet on a global scale, since the dark oceans absorb the greater part of the sun’s heat. This we should explore now, in case sudden climate changes force us to act quickly.
What makes these ideas dangerous?
They are dangerous to those environmentalists who find all such steps suspect—smacking of engineering rather than self-discipline. Yet if Kyoto fails to gather momentum, as seems probable, what else can we do? Turn ourselves into ineffectual Mommy-cop states with endless finger-pointing politics? Try to equally regulate both the rich in their SUVs and Chinese peasants who burn coal for warmth?
Our present conventional wisdom might be termed the Puritan solution (“Abstain, sinners!”) and is making only slow, small progress. The Kyoto accords call for the industrial nations to reduce their carbon dioxide emissions to 7 percent below the 1990 level, and globally we are further from this goal with every year that passes.
These steps are early measures to help us assume our eventual twenty-first-century role as true stewards of the earth, working alongside nature. Recently Billy Graham declared that since the Bible made us stewards of the earth, we have a holy duty to avert climate change. True stewards use the Garden of Eden’s own methods.