Monday, June 13, 2016

A Summer Reading List

I just turned 26. When I was in high school our environmental education was very good, compared to what has been taught for most of human history. Silent Spring had been out for decades, and most people had seen An Inconvenient Truth. We knew a lot more about the science of the environment, and as students we were painted a bleak future of doom-soon extrapolating graphs. The urgency of the material and environmentalist exhortations of individual action was undercut by our teachers' (sometimes unconcealed) feeling of powerlessness. Scaring people in environmentalism is a double-edged sword; you push some people into action, but for many others it becomes easier to detach emotionally: “we're all screwed, so what do I care?” And the more dire predictions you use, the more like a millenarian cult leader you sound. We're running out of tungsten! No more lightbulbs! Then it turns out LED lights are more energy efficient anyway. People stop listening when you're constantly predicting a rapture that never comes.


And yet this was the tone of much of the environmental and biological literature I read for this project. Even when dispelling myths like the 50,000 species some say are going extinct a year (which is based on a completely made up number), one of their primary concerns is inspiring donations and grants for their research. Not that this is a bad thing; research on current extinctions is very important, and the true number that occur per year is undoubtedly still a scary one. But knowing that the articles in a lot of the books were recommending very specific courses of action made me warier of them. If not the numbers themselves, but the picture they were painting with them. I hate being sold, even on a good cause. I'd much rather come to the same conclusion on my own.
Even so, biologists talking about the current human-led biodiversity loss basically agreed that convincing people of the importance of biodiversity loss is the foremost challenge of the 21st century. If I'd originally been asked to say why biodiversity is important, I wouldn't have had a ready answer but I could have reasoned my way into a few. Now I had several: biologists, eager to convince readers of the importance of biodiversity, have long lists of reasons why it's important. They all made sense and yet, I kept thinking, the species we have lost in recorded history have mostly been localized, fragile ones. Island species, ones with very specific eating habits or habitats, ones without much competition. It's easy to romanticize the loss of the dodo, but hard to see what the extinction of a strange flightless bird on a single island means for the future of our planet. As did more practical concerns like cures for diseases that have yet to be discovered, compounds for industry that have yet to be extracted from endangered Amazonian beetles. And more abstract ones, like the existence of a tipping point which once passed will cause massive chains of extinction. Mourning the loss of things we don't have yet and theoretical problems we may face; I could see why getting people to care about these things would be a challenge!

Ironically, it took me reading less alarmist paleontological sources to start to get worried. Especially when they came to the same conclusions as the biologists had. The history of mass extinctions is interesting; we know of at least five that meet the threshold we created, but large extinction events have been happening almost continuously since there has been life on Earth. Paleontologists are generally divided on their causes, but I read good summaries of their consensus opinions.


Two things that I learned stuck out to me. One was just how variable the Earth's climate has been over both the short term and long term. The gas composition of the atmosphere, the temperature, the sea level and its chemical composition, all of these things fluctuate massively all the time. The current sea level is almost the lowest it's ever been in the Earth's history, as is the level of CO2 in the atmosphere. It surprised me that even though the short term increase in CO2 that we worry so much about may have dire implications for our planet, in terms of hundreds of millions of years, a lack of CO2 is predicted to be a bigger problem, as trees gradually convert virtually all of it into oxygen. It was also fascinating how much life determines its own conditions. Changes in microorganisms can completely shift chemical conditions in the oceans, for example. Runaway reproductive success for one type of organisms was always a key component in theories of mass extinction.
Paleontology is all about time scale, and the long one is often counter-intuitive. Paleontologists generally agree that a large meteorite only had a hand in one of the mass extinctions, the C-T one that killed the dinosaurs. Except the fossil record seems to show that most dinosaurs were already extinct by then, and only two groups were wiped out. Like when I researched the near-extinction of the bison and found evidence that their numbers had already been falling for centuries before the arrival of Europeans, extinction seems to not usually be that dramatic. More often, it's a gradual fading away of an old species in its sleep rather than a young species in its prime.
That said, cascading chains of extinction can and have taken out otherwise successful species. The second thing I found striking was that in mass extinctions, there was always an accompanying drop in biomass, the amount (not diversity) of life on Earth. Maybe this is obvious, but I didn't see why having lots of types of organisms go extinct would necessarily mean there would be less tons of living stuff, worldwide. If some things were out-competed by others, aren't successful species then more numerous to make up for it? Apparently yes, but not in the long term, because of the extreme variability of the Earth's climate. So if Australia gets a couple degrees cooler, the cane toads, a newly introduced species, might all die because they can't take it, whereas the older established species that they wiped out would have survived (because the very fact that they're old species means they've probably survived a similar cooling period in the past).

This fact, that species exist places because they are best suited to live there in the long term, and that allowing them to be extirpated can create lifeless wastelands in the relatively short term, really convinced me. Life is just something that's managed to make solar energy useful to itself, hung on through severe climactic variations, and even had a hand in dictating its own conditions on Earth: creating an atmosphere, making the planet able to better sustain life. It's totally possible for the efficiency at which life converts solar energy into a variety of living things to fall apart until, like Mars, it's just sunlight hitting bare rock. The less biodiversity we have, the more delicate our balance, the more dependent we are on current climactic conditions staying the same. And they're always changing, that has never happened! We need as many players as possible ready to step up when their time comes, and then fade into the background when others are better suited, slowly changing and branching out to be ready for when they're needed again.

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