The level of CO2 in the atmosphere was 280 parts per million in the late 1800s, just over 300 ppm in the 1950s, and today it's 387 ppm. With the world's increasing populations, rapid growth in emerging mega countries, and first world's refusal to reduce or commit to meaningful caps, that number is increasing 2 to 3 ppm per year. At 450 to 500 ppm the planet will see mass extinctions.
In the trailer below for the documentary A Sea Change (which I saw earlier this week with a bunch of Alaskan environmentalists), one scientist asks another if it is already too late for the planet, posing the question with a surprising lack of jargon: "Are we screwed?" He says, "Yes."
One example well underway: Increased CO2 levels cause a decrease in pH, making the oceans more acidic. In our current phase the most drastic impact has been on calcifying organisms: coral, shellfish, and the charming tiny blips above, the pteropod, who were the stars of Elizabeth Kolbert's landmark New Yorker essay The Darkening Sea. The water's increased acidification is causing the pteropods' delicate shells to dissolve, the first step in a collapsing food chain as they account for fifty percent of pink salmon's diet.
Crucial as the subject is, the documentary disappoints because it's framed as a 65 year old former teacher's letter to his grandson. Again and again he interviews leading scientists and wastes time asking, "How would you explain this to a five year old?" The too brief underwater footage is far more compelling than the treacly interludes of man and grandson fishing, or swimming in a pool, or walking to school.
Many intelligent people I know dismiss all doomsaying scientific predictions just because killer bees and avian flu failed to deliver their promised catastrophes. This one seems real, though being out of sight it's harder to fathom.
Personally, I'm looking forward to the planet's warming enough so you can invite me to AK for a beach vacation.
Posted by: Steve | January 15, 2010 at 11:24 AM