Permian labyrinthodonts and Arctic Bedouins

Here’s one way to help you stay in denial about climate change.

A friend of mine recently insisted: “Temperatures and CO2 levels have been much higher in past history. During the Eocene [50 million years ago] the CO2 level reached 2,000 parts per million (ppm), compared to less than 400 ppm today. Climate changes constantly.”

Yeah, okay, but there are a few items left out of this analysis. Here is a short history of earth temperature, CO2 levels, and climate change:

Planetary temperature and atmospheric CO2 remain intimately linked, always and forever, like devoted lovers. Yes, CO2 levels and temperatures have been much higher than they are today, but the intense heat wiped out everything on land except lizards, tough plants, insectivores, and a few burrowing marsupials.

About 250 million years ago (mya) the earth began heating up, leading into a long “Mesozoic Heat Wave.” At this time, earthly life systems experienced the largest environmental collapse of all known history, the Permian extinction, claiming 95% of all species. A meteorite, volcanic eruptions, or other influence may have caused this. The planet experienced run-away heating. Lizards and trees thrived in the heat. About 100 million years ago, atmospheric CO2 levels peaked at about 2000 parts per million (ppm), with a few spikes going even higher, the earth’s maximum CO2 build-up and hottest period in known history. But the emerging and spreading forests helped cool the earth. You can thank the Cretaceous Angiosperms for hanging in through the long hot “summer” that lasted 200 million years. Keep in mind: The forests cooled down the planet by removing carbon from the atmosphere, allowing large mammals, such as humans, to evolve.

As the trees gobbled up carbon, atmospheric CO2 dropped, and the planet cooled until the series of ice ages we all know. After the last ice retreat, humanity spread around the planet, began to build cities, and the earth has been gradually warming for the past 1000 years, with minor fluctuations. Pre-industrial concentrations of CO2 remained stable around 280 parts per million. For our purposes of devising a human plan for the next few centuries this pre-industrial level of carbon in the air is our baseline, not the extreme Mesozoic levels from 100 million years ago, since nothing remotely like human civilization could have survived the Mesozoic heat.

Since the 1800s – due primarily to human hydrocarbon burning and forest destruction – CO2 in the atmosphere has risen on an exponential growth curve resulting in the current 400 ppm, record temperatures, melting icecaps, monster hurricanes, and unearthly denial on the part of our alleged leaders. We’ve witnessed a 43% growth in atmosphere CO2, mostly in the last 100 years. Anyone can follow the curves for atmosphere CO2 and planet temperatures. They travel together.

See “Simple Models of Climate”:

James Lovelock, who has been tracking this problem for forty years, points out that even if we did all right things now, the current levels of CO2 in the atmosphere could continue to heat the planet for a thousand years until the forests returned. But we’re not doing the right things. We’re driving gas-guzzlers. China’s planning 110 new coal-fired plants. We’re cutting down 30 million acres of forest a year. We’re losing 20 thousand tonnes of top soil every year. We are turning forest into farmland, and farmland into desert. All of this heats up the atmosphere.

If current CO2 growth continued for three centuries, we’d be at 1000 ppm, but of course we’d never get there, because we’d bake first. Even now, we’re watching the ice melt like the poor Permian labyrinthodonts with the possible exception that we may know what’s going on.

If the increased heat absorption from ice melting does take over or add critically to human hydrocarbon burning and forest loss, we could fry, and a few huddled Arctic Bedouins may have to hold out for a hundred million years. Maybe this won’t happen, but that’s not the point for our children’s children, and their children. For them, we have to wake up and do everything humanly possible to reverse our Big Blind Blunder. The posturing and denial just prolong the mistake. Nature will not be mocked.

A high school class could do the math. There is no real mystery in this, except of course the big mystery of the universe itself. The so-called uncertainty is just ordinary scientific uncertainty that all scientists know as their constant companion. The variables remain vast and complex but the data and general trends remain clear.

Climate prediction is more complex than most science because climate modeling is not a typical experimental science. Nature controls the experiment. And therein lies the important paradigm shift for humanity: “You are inside the experiment!” Wake up and read the data. “You don’t believe in ghost stories?” Captain Barbaroosa says in Pirates of the Caribbean: “Well, you better start believing. You’re in one.”

In 1979 we had a graph of exponential atmosphere CO2 in our Greenpeace Chronicles office on 4th Avenue in Vancouver, Canada. I can see it now, stuck to the wall with a thumbtack. Anyone paying attention then, Lovelock for example, knew what was coming.

Don’t get depressed. Get informed and get active.

This was posted on Monday, February 12th, 2007 at 1:36 pm and is filed under Ecology . Feel free to respond, or trackback.