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Dear Lola,
I am writing to you while sitting on a rock in open Sonoran desert. I am at Organ Pipe Cactus National Monument, on a road called Puerto Blanco Drive. When I first visited Organ Pipe, this dirt road went on for fifty-two miles through some of the most remote sections of the Sonoran desert.
Times have changed. A drug war just over the border means Puerto Blanco Drive is no longer safe. In 2002, Ranger Kris Eggle was in pursuit of a drug cartel hit squad, which had fled Mexico after committing a series of drug-related murders in Mexico. Eggle died in a face-off with the bandits.
As post 9/11 security has strengthened border areas, crossing into the United States through the vicious environment of Organ Pipe Cactus has become a more promising alternative to other crossing points.
Now, Puerto Blanco Drive is gated at five miles, and so I have walked into the wilderness from this point. Not a single car has driven up this road all day. Because of the swine flu outbreak, nobody seems to be traveling. The desert will be shared between the border agents and myself.
I spend the entire day out here. When you are really quiet, this barren place just opens up with life. For some of the day, a coyote has been trailing me. Coyotes remind me of barracudas, because they both seem to know that their are advantages to trailing large animals. They are always there, but you hardly ever see them until you sense something staring at you behind your back.
I am amazed, also, at the dragonflies out here. I just spotted a flame skimmer, a brilliant orangish-red insect. I read recently, that we have found dragonfly fossils from the carboniferous period that had wingspans of nearly a meter. This was a time in Earth's history when we saw incredible gigantism in animals and plants. You know how sometimes you see those tiny shoots that mosses produce in the spring? In the carboniferous period, those shoots rose to the height of trees and amphibians grew to the size of large dogs.
Scientists believe that there is an upper limit on how large an insect can grow, and so a meter-long dragonfly is just a physical impossibility. Why then, did the carboniferous period contain dragonflies like Meganeura; impossible giants?
Meganeura could exist because the atmosphere of the carboniferous period was very different. The air contained 20% more oxygen than it does today, and it is believed that this more oxygen-rich atmosphere allowed insects to develop larger wings in response to an atmosphere that favored their need for rapid use of oxygen.
The carboniferous period was host to an extinction event, where many species, particularly marine species, went extinct in a relatively short period of time. Scientists believe that this event was a result of climate change. What's interesting about all major extinction events is that there is strong evidence for most of them as being brought on by atmospheric changes - essentially, climate change.
It's starting to get dark now, and I start walking again. On my way back to the car, I summit a rocky hill. In the strange light, with clouds in the distance, I can see a vast valley of cactuses and creosotes below me. This vast valley, closed off to public use for fear of drug runners and border crossings, looks wicked in the dark. What desparation would cause young women and their children to flee through this lonely land?
Darker, and I can see stars. We forget to think about this space we live in; the air, the atmosphere. Our breathable atmosphere, about seven miles high, is so thin that mountain climbers can escape it. We live in a thin band of habitable atmosphere - this is the lower level of the atmosphere - the troposphere. Tonight, with the wind and the clouds and the night birds in the air, I can see it in action.
In the course of our many years of debates about climate, you often brought up issues about our atmosphere. You found arguments on the world wide web and forwarded them to me as evidence that climate change science was still up in the air.
These arguments were often collectively flawed in that the author used something in atmospheric science that he didn't understand, in order to advance a non-scientific argument that sounded good or apparently promoted his position. We'll go through some of these arguments in Utah, and some in California, and some in Oregon. We'll dispel each of them slowly, while looking for pikas on mountaintops and paddling through shallow rivers. I intend to have some fun with this, and I hope you will too.
Lola, follow me through the Americas, because I want to show you a few things about the air.
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