Freeman Dyson on Climate Change

The New York Times has an article on eminent physicist Freeman Dyson's skepticism of climate change arguments. Several passages struck me in particular:

Dyson agrees with the prevailing view that there are rapidly rising carbon-dioxide levels in the atmosphere caused by human activity. To the planet, he suggests, the rising carbon may well be a MacGuffin, a striking yet ultimately benign occurrence in what Dyson says is still “a relatively cool period in the earth’s history.” The warming, he says, is not global but local, “making cold places warmer rather than making hot places hotter.” Far from expecting any drastic harmful consequences from these increased temperatures, he says the carbon may well be salubrious — a sign that “the climate is actually improving rather than getting worse,” because carbon acts as an ideal fertilizer promoting forest growth and crop yields. “Most of the evolution of life occurred on a planet substantially warmer than it is now,” he contends, “and substantially richer in carbon dioxide.” Dyson calls ocean acidification, which many scientists say is destroying the saltwater food chain, a genuine but probably exaggerated problem. Sea levels, he says, are rising steadily, but why this is and what dangers it might portend “cannot be predicted until we know much more about its causes.”

and

Beyond the specific points of factual dispute, Dyson has said that it all boils down to “a deeper disagreement about values” between those who think “nature knows best” and that “any gross human disruption of the natural environment is evil,” and “humanists,” like himself, who contend that protecting the existing biosphere is not as important as fighting more repugnant evils like war, poverty and unemployment.

His basic argument seems to be that, yes, human activity is causing global temperatures to rise, but this may not be a bad thing. Life, and humanity, will adjust to life in the new climate through adaptation and evolution, and may even emerge richer and stronger.

In a long-term sense, he is completely right. Life on earth has survived much greater shocks in the past and will likely continue to adapt and evolve as long as the sun is shining. We humans are a particularly adaptable bunch; we don't need to wait for genetic evolution to change our behaviors. We have devised ingenious solutions to our problems in the past, and we could probably think of something to carry us through whatever changes may come.

But the problem with this argument is the short-term. Humanity and life in general may be infinitely adaptable, but the fact is that, for the moment, we have adapted to life on the planet the way it is. We depend on certain plants and animals for food. These plants and animals in turn depend on other plants and animals, as well as certain chemicals and climate conditions. Every step in this chain is, for the moment, perfectly adapted to the climate of the present. Nature has even devised its own mechanisms to keep the current climate in place: for example, ocean bacteria help regulate the earth's temperature and atmosphere. We are, at present, in a state of equilibrium.

Massive increases in carbon dioxide, leading to rapid temerature growth, would push us out of equilibrium. Nature's homeostatic (equilibrium-maintaining) mechanisms would be insufficient to maintain our current climate, and large changes would occur. Food chains would have to be restructured as intermediate links go extinct. Some species would win and some would lose in the scramble to adjust to the new status quo.

Ecologists know that an ecosystem pushed out of equilibrium will eventually reach some new equilibrium state. But the details of this new state are impossible to predict ahead of time. Which species will dominate? What new food chains will form? This is the big question of climate change; no one can really say.

As far as we humans are concerned, the odds that this new state will be better for us are pretty low. Consider, for example, that the typical American diet is built from a relatively small variety of fruits, vegetables, grains, and animals. And the genetic variety within these crops is decreasing as breeds become standardized within the agriculture industry. It's unlikely that the specific plants and animals we depend on will be winners in the new equilibrium, since they, like us, are adapted to what we have now. We will have to scramble to change how we eat, as well as where we live, thanks to sea level changes. Millions of lives will be disrupted in this change. We have to ask ourselves, as a society, if we this disruption is an acceptable tradeoff to maintain our current energy habits a little longer.

As mathematician and ecologist Simon Levin said, “Nature is not fragile... what is fragile are the ecosystems services on which humans depend."