First - I know. I've totally been feeling guilty about the fact that I haven't posted in almost two months. Not because of a lack of interesting things to post but because I've been working on a story for Newsweek, due out in February (more on that later). It took up a lot of that two months; the rest of my free time was taken up by baking these beauties:

But the cookies have long been devoured, a new semester has begun and I'm getting back in the saddle with a 9am class called Energy and Climate Change.

So far, it's been an overview of climate change in context of the earth's history and we started with something our professor called "The Great Oxygen Catastrophe". This is a pretty simplified version of the actual events but I think it covers the basics.

3.5 billion years ago, blue-green cyanobacteria evolved on earth. These little organisms were capable of photo-synthesis and, as part of that process, they released oxygen into the atmosphere as waste. Keep in mind that, prior to this, there were no loose oxygen molecules bouncing around in earth's atmosphere - it was all absorbed immediately by other molecules.

Over the next billion or so years, as these cyanobacteria were giving off oxygen, it was still being taken up by all those other molecules, like iron - which created rust - or hydrogen - to create hydrogen peroxide. The earth was, essentially, a giant oxygen vacuum, sucking up all the oxygen.

As the earth began to cool and change - with fewer volcanoes spewing hydrogen and much of the iron already saturated - more oxygen molecules were left untethered, free-wheeling around the atmosphere. This is somewhere between .75 and 2 billion years ago (give or take a few days). But oxygen was toxic to much of earth's anaerobic residents and they were almost entirely wiped out - meaning these cyanobacteria basically caused one of the most significant extinction events in earth's history.

Maybe you see where this is going?

Fast forward to, oh, say the modern era. In what could be seen as a striking similarity, there's a relatively new population of creatures on the planet that have been steadily increasing their emissions of carbon dioxide for the past 150-200 years. For a while, the earth was absorbing all those CO2 molecules without too much trouble but it's starting to reach a saturation point. The result could be another of the most significant extinction events in earth's history.

It's an interesting parallel. Andrew Revkin had this to say about it on his blog, Dot Earth:

"...you could step back and say there's not much of a difference between our carbon bins and that oxygen outburst. Except those mats of photosynthesizing slime weren't looking up at the sky, measuring and marveling at what they'd done. Through science, we are. With awareness comes responsibility, at least in theory. I'm pretty sure cyanobacteria are not self-aware."

We, as a species, have an opportunity to do something different. We're not pre-programmed to continue down the same path mindlessly. We can change the current course, reduce emissions, try to undo some of the damage we've done. In other words, we've evolved beyond the level of cyanobacteria - maybe it's time to act like we have.