Thursday, May 12, 2005

Holding Back The Tide
Much of the discussion of climate change in the popular media focuses on the potential for stronger and more frequent hurricanes, melting icecaps, and loss of habitat for endangered species. This recent op-ed from the New York Times reminds us of the human face of some of these issues. As sea level rises, even by a foot, a small amount of habitable land, including islands and coastal areas, will be permanently lost. While tiny as a percent of the earth's landmass, these losses could evict millions from their homes. The consequences of this for global society and the economy would be significant.

What makes this problem all the more frustrating is that even drastic, immediate action against climate change, including severe cuts in emission-producing activities and the reforestation of large tracts of land, would probably not avert at least some of these outcomes, because of the inertia of the climate system and the persistent effect of higher greenhouse gas concentrations in the atmosphere and of warmer seawater.

The UN High Commission on Refugees (UNHCR) estimated that there were 20 million refugees globally in 2002. Although the recent South Asian tsunami added to that number, the authors of the Times op-ed suggest it could multiply to 200 million by 2080, due to rising sea levels. That does not include additional dislocations from persistent changes in rainfall patterns and agricultural productivity. This is a daunting figure and would completely overwhelm the existing and already-stressed mechanisms for dealing with refugees and immigration.

Estimates are only educated guesses, and I'm well aware of the distortions that flawed assumptions can generate, particularly over a span of time such as the one cited above. But if even a fraction of these people are displaced from their homes, it will create a human migration that would rival anything we've experienced previously. While the op-ed suggests preparing to receive them, noting the demographic benefits they might bring with them, we need to consider other solutions that might be less disruptive for all concerned. Adaptation will be the key, including the construction of dikes, levees and seawalls on a massive scale. Island populations could be transported to uninhabited islands that are less threatened, and provided with development assistance to recreate their infrastructure, which might have to include seawater desalinization, if fresh water isn't available.

This may sound daunting, but the technology is available today, and the cost to us of helping people to adapt where they are would likely be less than asking the US to absorb 50 million immigrants, on top of the millions who will come here from other places and for other reasons in the same timeframe. And it might just be more amenable to the populations affected. If you give people the choice between saving their homes and having to move to a strange place, I'm betting most would choose the former.

Adaptation doesn't get us off the hook for addressing the causes of climate change, as some of its opponents fear. Rather, it's a complementary and necessary strategy for both the developing world and the developed world. But unless we also attack the root causes of climate change, we just might be presented with a planet to which the entire global population of 8 or 9 billion (by then) of us cannot adapt.

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