Noah Millman argues that although “a rise in sea levels and an increased incidence of extreme weather are the easiest parts of climate change to understand, they aren’t actually the most important.” He makes some reasonable points:
Human beings adapt pretty readily to flooding. We know how to build sea walls, and ecologically-sophisticated systems of flood control. In the extreme, we know how to move – we are a highly mobile species.
It’s less clear how well we’d adapt to wholesale changes in the ecology attendant on changes in CO2 levels. An increase in the acidity of the oceans, for example, could significantly disrupt the marine food chain (what’s left of it after over-fishing). A wide variety of land-based species are also sensitive to changes in the climate; global changes could have an unpredictable global impact on overall biodiversity. The earth, of course, will adapt just fine; the terrestrial climate has seen some pretty huge swings over geological timescales, and the diversity of life has recovered from multiple mass-extinctions. Human beings, though, have only been around for a million or so years (much less depending on how picky you are about what counts as “human”), and large-scale civilization is only a few thousand years old. We have no idea how well that civilization would adapt to widespread ecological disruption.
Moreover, there is a synergy between efforts to reduce the impact of human activity on the environment and efforts to repair or adapt to the consequences of that activity. The slower the rate of CO2 and methane emissions, the slower these changes will progress; in effect, we’d be buying time to adapt.