350ppm Misses the Forest
Going to refine this post, and let me preemptively apologize to the good people of 350.org, but, 350ppm as a safe level of atmospheric CO2 doesn’t seem to integrate the data (i.e. see the trees for the forest). In the ice record, there is not a single instance of 350ppm CO2 in 600,000 years, except extremely recently, i.e. the 1990s. CO2 reaches about 275 or 280ppm then drops. I ain’t no expert, but given the repetition of this phenomenon, it seems as if there is a mechanism in the climate system that sets off an ice age once 280ppm is reached.
Now, I am writing this from memory, and it’s been awhile… (I’ll look things up and cite them as appropriate, but for now…) Terms such as thermohaline flow and North Atlantic “Achilles Heel” come to mind; it works out to this: ice melting in Greenland becomes fresh water in the ocean, and the difference in the density of this melt water and the salt water displaces the flow of the Gulf Stream, slowing it down. I think a normal flow rate is 5 billion gallons per second, but recently, it’s slowed down a lot. The last time it was at its current rate was 14,000 years ago, preceding the last ice age/right at the beginning.
Anyway, when the Gulf Stream shuts down, it causes northern Europe and Asia to get cold and snowy, same with North America, and an ice age begins. Someone with more time should try to pin down a correlation between less plant life uptaking CO2 on land and a global reduction in atmospheric CO2, but if I was to guess, I’d say while plant life on land does take up CO2, it also gives it off when seasons change, and warmer land translates to active soil bacteria and decaying plant matter in wetlands. Some of this bacteria produces methane, which as anyone that pays attention to this subject knows, is a potent atmospheric insulator. Therefore, freezing out the northern-most areas of the continents reduces the emission of atmosphere-heating gases. At the same time, phytoplankton are still active, thus the concentration of atmospheric CO2 does eventually fall. Over the course of, like, 10,000 years.
The added wrinkle due to CO2 being up to about 418ppm right now, and this is a total guess, cuz I haven’t read anything even venturing a hypothesis in this direction, is we got a whole lotta melted glaciers coming even if another ice age is on the horizon. How? Wellz, the Gulf Stream conveys heat from the equator to northern Europe, and while that would stop at the beginning of an ice age, the added heat not escaping the atmosphere is still present. And, even now, the ocean is warmer farther away from the equator than it historically was because of the added heat. Now, it’s a total leap to get to this excess heat continuing to melt the ice in Antarctica, but, the heat has to go somewhere, heat moves to cold, there’s a lot of cold to absorb it in Antarctica… Plus, in even more ancient times when CO2 concentrations were this high and higher, sea level was higher. Once again, I have to look this up, but from the fossil record, the last time CO2 was this high, “coastal Virginia” was either 90 miles inland from where it is today, or sea level was 90 feet higher than it is today—there are clam shell fossils on a former beach in the Appalachians that were deposited after the mountains rose.
Point being, self-deception is a common human problem, especially when we don’t want to face realities that require us to drastically change our behavior. Physics cannot be reasoned with, denied, or escaped. Let’s be honest about the situation we are facing so we can design systems to remove the excess CO2 on a shorter time scale than nature will do on its own. (I will share my ideas about said systems in a future post.)