Archive for April, 2010

Happy Birthday, Earth!

Sure, your birth certificate says you are 4.6 billion years old, but who can picture such a number? It’s simpler to imagine that you were born at the stroke of midnight on January 1st, and that it is now midnight again, exactly one year later. You’ve accomplished so much in that time!

You spent three months just cooling off and letting water vapor condense into rain to fill your oceans. By about March 5th, you had already become home to single-celled life forms. You suffered your first environmental disaster in early June, when some organisms began releasing the toxic chemical oxygen into the atmosphere. Many life forms died, and others retreated to hidden places where the poison couldn’t reach. A few, however, learned to thrive, using the oxygen to produce energy. By August, eukaryotic cells with nuclei had developed, enabling even more complex life forms to evolve.

And evolve they did, into some amazing creatures. Around December 12th, the mighty dinosaurs appeared, to rule the planet until around 8:00 PM the day after Christmas when they mysteriously disappeared. This afternoon, December 31st, at about 7:14 PM, some strange-looking apes appeared, walking on two legs, and by 11:37 (23 minutes ago) they had evolved into us, homo sapiens. We have turned out to be an astoundingly industrious species. We built the pyramids at 11:59 and 36 seconds. A little over 1 ½ seconds ago, we invented the steam engine and started the Industrial Revolution. Since then we have built the modern world of today, with all its technological wonders, and have developed an overwhelming sense of confidence in our abilities.

You’ve had a bit of trouble holding your temperature steady over the past year; you’ve developed a chill at least four times that we know of. We think the earliest was around late May, then again just before Halloween, again at Thanksgiving, and finally as late as this afternoon, around 4:22 PM. During these cold spells, snow and ice covered much of your surface. In between these periods, your temperature rose enough to shrink the ice caps to a tiny area at the poles, leaving even Greenland and much of Antarctica ice-free. Since those regions are ice-covered today, you must still be recovering from your latest cold.

These changes haven’t gone unnoticed by us, and we have grown ever more sophisticated in our analysis of the climate. We now feel confident that we know what is going on. Seven tenths of a second ago, we declared that you were growing colder. Then, a little more than half a second ago, we corrected ourselves and pointed out that the temperature was getting warmer. Less than a quarter of a second ago, we recognized our mistake and said no, you were actually growing colder, and perhaps we should spread a layer of black carbon over your ice caps to warm things up. Then, about one tenth of a second ago, Al Gore straightened us out and said not only was the climate getting warmer, it was our fault! For a while, we called this “Global Warming.” Unfortunately, our scientists now tell us that you have actually cooled off a bit over the past five one-hundredths of a second, so we now call it “Climate Change.” But we are sure it’s still our fault.