Many approaches to climate change policy

I found Paul Higgins’s article, “How to deal with climate change” (Physics Today, October 2014, page 32 ), a useful and balanced summary of the high-level policy options that are available. However, he omits a few points that are often glossed over in discussions of the issue.

First, it is true that we will have to adapt to climate change. Even if carbon dioxide levels were to stabilize today, Earth would continue to warm for decades, sea levels would continue to rise for centuries, and biological systems from fisheries to forests would respond to those changes. But adaptation without mitigation is folly. If CO₂ levels do not stabilize, any attempts to adapt to climate change will eventually be insufficient and will need continual augmentation. In that unstable scenario, the costs of adaptation will eventually exceed those of mitigation.

Second, the biological world generally is much less adaptable than humans. Some biological systems may simply not be able to adapt fast enough and may fail catastrophically. Given our huge reliance on the services provided by biological systems, figuring in the societal loss from those systems’ inability to adapt should push the balance even further toward mitigation.

Third, although Higgins mentions the immediate loss to our economy due to the degradation of biological systems, he does not mention the decimation of biological capital that would result from climate change. I argue that the planet’s most valuable natural resource is the vast store of information in the DNA of the millions of species that have developed over a billion years of evolution. Humans have barely started exploiting that treasure trove for new medicines, foods, materials, and more. Yet biologists tell us that even without climate change, we are in the midst of the sixth great extinction on this planet. Climate change will only accelerate the loss of species. Shouldn’t that particular loss figure into calculations of the costs of climate change and the debate over mitigation versus adaptation?