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.

Is Climate Change Hell Now Inevitable?

Is Climate Change Hell Now Inevitable? | Common Dreams

We know from the geologic record that runaway methane releases have occurred several times in the past.  Some 55 million years ago, during what geologists call the Paleocene-Eocene Thermal Maximum, temperatures soared, as clathrates (or as they are sometimes known, hydrates) released massive amounts of carbon, mostly in the form of methane.  Many scientists believe this was triggered by volcanic releases of carbon.  Other factors may have been at play, but the key takeaway is that methane releases caused runaway warming that lasted for more than 150,000 years, and that today, humans are releasing carbon at ten times the rate that is thought to have triggered the releases.

Extinction

The coral reefs are dying. These largest of all earth’s living structures, intricate and brightly colored, home to a vast panoply of colorful fish, mollusks, marine life of all kinds -- the superstructure of biologically diverse ecosystems -- are bleaching white, breaking up, and withering away.

It won’t be the first time that the reefs have died away. In each of the five previous mass extinctions, coral reefs have been severely impacted, taking many millions of years to recover. In this respect, reefs are like the canary in the coal mine. They are a sentinel, whose current calamitous condition foretells the sixth mass extinction, an event many paleontologists believe the earth has already entered.

The cause or causes of earth’s previous mass extinctions have been a matter of intense scrutiny. Hypotheses have ranged from massive volcanism to asteroid strikes. 

The Permian-Triassic extinction of 250 million years ago (Mya), wiped out over 90% of the planet’s marine species. On land, over 70% of reptile, amphibian, insect, and plant species went extinct. It was the most catastrophic of all earth’s extinctions, and may have been triggered by the eruption of the super volcano known as the Siberian Traps, the most massive eruption and lava flow in earth’s history.

The Siberian Traps eruption, which lasted for a million years, added huge amounts of heat, carbon dioxide, and sulfur dioxide to Earth's surface and atmosphere, and the resulting greenhouse effect generated a long warming trend. The climate change triggered by the warming dramatically shifted weather patterns across the globe.

Carbon dioxide has left its fingerprints on all the massive die-offs experienced during earth’s often violent history. J.E.N. Vernon (2008) has pointed out in his article in the journal Coral Reefs, that recent palaeophysiological studies have clearly implicated CO2 in the destruction of most life on earth during the Permian-Triassic extinction.

There is also evidence of a sudden and massive release of methane, perhaps triggered by increased warming. This would have been an example of positive feedback, that is, CO2 causing warming, melting frozen tundra, and thereby releasing methane, which is considered a much more potent greenhouse gas than CO2.

As it happens, Russia’s Siberian tundra is currently melting. Russia has the largest extent of permafrost in the world. Scientists estimate that permafrost covers more than 10 million square kilometers of Russia. The warming planet is melting permafrost in Siberia, and the melting permafrost is releasing methane in much greater quantities than previously thought. Methane is considered 20 times more damaging as a greenhouse gas than carbon dioxide, which means that Siberia is now actively contributing to  warming. Russian scientists believe the melting of Siberian permafrost is irreversible, as the release of green house gases will perpetuate the warming climate.

Experts say Siberian tundra leaking methane in record amounts

And this brings us to the Sixth Mass Extinction -- the one happening now. We’ll address that in a coming blog post.