Tipping points have been a major theme in this week’s classes. Starting with our reading of the book Six Degrees by Mark Lynas, and continuing into lecture and discussion. They have been both a major source of worry and hope. There are many environmental tipping points that could spell disaster for mitigation efforts, there is an equally important social tipping point that could speed us on our way to global cooperation in the face of the climate crisis.
I’m going to start by discussing a few tipping points in greenhouse gas emissions and global warming, and why they scare me so badly. At a certain point, our warming climate will begin to emit more greenhouse gasses in a dangerous positive feedback loop. As ice caps and glaciers melt, they reflect less solar radiation back out to space (IPCC, 2013). The subsequent sediment build up on top of ice sheets in turn absorbs more heat and accelerates the melting of these areas. This decrease in albedo is something we’ve already seen, and will continue to see as climate change worsens.
Another major tipping point I’ve learned about recently is the release of methane hydrate compounds from the sea floor. These compounds are unstable, and very susceptible to changes in ocean temperatures. As deep sea temperatures rise, these compounds could explode from the sea floor, causing underwater landslides and tsunamis, as well as releasing hundreds of tons of methane into the atmosphere (Lynas, 2008). On a molecular level, methane is about 25 times more potent as a greenhouse gas than CO2 (Kump et Al, 2015), and this massive influx of greenhouse gas would increase the temperature further and release yet more of these methane hydrate compounds, creating another deadly positive feedback loop.
The last tipping point I want to mention is the point at which soil no longer sequesters carbon. After around 3 degrees Celsius of global warming, soils will begin to release their stored carbon dioxide, and stop sequestering more (Lynas, 2008). This would be catastrophic in the fight against climate change, as it would cripple one of our most effective tools for carbon sequestration.
One of the most intriguing and novel ideas I have come across is the idea of an anthropogenic tipping point in the fight against climate change. Dr. Wasserman brought it up after a rather depressing discussion of the book 6 degrees, in what I thought was a rather transparent attempt to keep us all from despairing. Nonetheless, I was hooked.
The main idea is that humans, and human culture, are like nature in the way of tipping points. Just like how there are many documented tipping points in the way of climate change – disappearing ice caps, methane hydrate releases, and lowering rates of soil carbon sequestration (Lynas, 2008) – human society works in tipping points. We saw it at the Berlin Wall in 89, when one after another soviet satellite states fell and we may see it again in the fight against climate change. As the blows from our changing climate continue to rain down upon us and our natural systems, it will eventually become impossible to ignore or deny. Either through ideological arguments, or more likely, economic arguments, there will come a time when we as a society make sweeping change. I can only hope we reach it before we go too far with our emissions.
Our lecture, and following discussion, on the book Six Degrees was thoroughly disheartening. It was a sort of meta analysis of many models and predictions designed to give a visceral look at what each degree of warming might look like. When the book was published 15 years ago, we had not yet passed 1 degree of warming, and now we’re approaching 2. This puts into perspective exactly how close these dystopian realities are.
My group, Annetta, Tommy, Wendy, and I, were assigned 5 degrees, only one away from the end of the book. Our chapter was so alarming that I don’t even want to think about what might result from 6 degrees. The sweeping themes of the chapter were a parallel to the Paleocene-Eocene Thermal Maximum, the destruction of most of the earths species, growing zones of inhabitability, massive numbers of climate refugees, and finally, a mass death event dubbed “the cull.” The Paleocene-Eocene Thermal Maximum was a geologic event about 55 million years ago, in which due to volcanic eruptions and methane hydrate venting, co2 levels rose to over 1000 ppm. The temperature increased 5 degrees over ten thousand years, and it caused a mass extinction. The poles became nootropics, and the tropics became far too hot for much life. The neotropics became desert wastelands, much in the same way they would if we hit 5 degrees. The main difference between these two times, other than the presence of humans, is the time scale. While we might hit 5 degrees in a century, it took millennia for these changes to take place back then. This gave species time to migrate and adapt, lessening the blow of extinction. Many did disappear, but many more than will be able to today managed to carve out new niches.
The theme of our discussion quickly became the nature of climate change. It acts sort of as dominoes, each degree of temperature increase sets off countless feedback loops that only add to the pile of emissions. The longer we wait to combat climate change, the more difficult it will be. That is why sweeping, meaningful action is required now, not just in the US, but at a global scale. I believe in our power to change for good, and I maintain my hope that we will solve this issue.
IPCC — Intergovernmental Panel on Climate Change. https://www.ipcc.ch/site/assets/uploads/2018/02/WG1AR5_Chapter04_FINAL.pdf.
Lynas, Mark. Six Degrees: Our Future on a Hotter Planet. HarperCollins, 2008.
Kump , Lee, and Michael E. Mann. Dire Predictions: Understanding Global Warming. Pearson College Div, 2015.
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