Going Extinct

In what seemed to me a bizarre encounter in the second presidential debate, the incumbent president and his challenger argued over which of the contenders for leader of the free world was more supportive of coal -- America's dirtiest energy source, and the country's leading source of pollution. No one following climate change developments could take any joy from the exchange, especially those fearing the earth is already experiencing what would be its sixth mass extinction.

Human activities are causing the earth to warm. There are no national or major scientific institutions anywhere in the world that dispute the theory of anthropogenic global warming (AGW). Not one. And we are already seeing the effects: longer, more intense heat waves, extreme drought, increased incidence of wildfires and longer fire seasons, loss of Arctic sea ice, and ocean acidification, among other things.

It will get worse, perhaps catastrophically so. Why? Because: (1) carbon dioxide (CO2), the primary driver of human-caused warming, takes centuries to dissipate in the atmosphere and global CO2 emissions continue to rise; and (2) many of the drivers of global warming produce positive feedbacks -- they are self-reinforcing -- and thus amplify the effects of global warming.

An example of positive feedback is the melting of Arctic sea ice. When sea ice melts, open water takes its place and being less reflective than ice, absorbs more solar radiation. This causes more warming, which in turn causes more melting.

To those who admit to anthropogenic global warming, but are content to wait it out, I suggest that their complacency, as well as being shamefully self-centered, may well be misplaced. Why? Because there’s the potential for a catastrophic climate destabilization.

Destabilization is an abrupt change in climate that would trigger dramatically shifting weather patterns, producing coastal flooding and torrential rains in some regions, and extreme drought in others, as well as an increasing incidence of hurricanes and tornadoes. These weather phenomena could occur in areas not normally accustomed to such events, such as the tornadoes that touched down in New York City in September of 2012, and super storm Sandy, that devastated the East Coast in October of that same year. In short, destabilization would lead to climate hell today, not in 2050.

Aftermath of Super Storm Sandy, Queens NY, 10/30/2012

Is this science fiction? Not at all. Paleoclimate records indicate that climate changes of this size and speed have occurred many times in the past. Furthermore, studies of the earth’s past five mass extinctions, including the one that wiped out the dinosaurs 65 million years ago (mya), have shown that a buildup of atmospheric carbon dioxide is a concomitant, if not the driving factor, in extinction events. The most devastating extinction in earth’s history, the Permian mass extinction, which occurred 252 mya, has been linked to a massive release of CO2 and/or methane.

At over 390 ppm, the amount of carbon dioxide in the atmosphere currently is unprecedented, at least in the last 400,000 years. At the same time, we are seeing the release of methane (a greenhouse gas 60 times more powerful than CO2) from thawing permafrost, as well as from the Arctic sea bed, and from unstable water bound deposits all over the world. The release of methane is a self-reinforcing process. A runaway methane release will very likely trigger abrupt climate change, and bring earth’s sixth mass extinction event to its apogee, and the destruction of most life on earth.

If we can go by the record of past mass extinctions, the earth will, over a few million years recover from this human-caused extinction event, but earth’s newly evolving tree of life will develop in whatever way the environment dictates. The chances the tree will include a homo sapiens limb is slim to none, which is probably for the best. We had our chance, and blew it.