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Global Warming
Jun. 21st, 2010 02:07 pmI've lately been updating my knowledge of paleogeology, a field that has always interested me, but which I've never really followed in any organized fashion. It turns out that there have been a lot of interesting developments in the last 20 years since I left university, which I have only heard about in bits and pieces. Having these pieces put together into a coherent whole has answered a bunch of questions I've had.
I'm not going to go into most of it, but one of the interesting things that I've known for some time is that CO2 levels have been much higher at some times in the past than they are now. In fact, it turns out that for the vast majority of Earth's 4.5 billion years, CO2 has been significantly higher than it is now, and the Earth has been much, much hotter. The only time in the geologic record where the CO2 amounts have been lower than recent history was during the so-called Snowball Earth period some 650 million years ago, at the dawn of multi-cellular life.
It appears that the most recent ice age (which we are still technically within, although currently enjoying a short-lived interglacial period) was caused by vast amounts of orogeny due to continental collisions, since mountains are one of the major geologic sinks of carbon dioxide. Right now we have the Alps, the Rockies and Himalayas as major mountain chains, and they are all absorbing CO2 as they erode. This is very unusual on geologic time scales.
What does all this mean? Well, it seems that the Earth in general and life in particular are currently in no danger at all from any amounts of carbon dioxide that humans are able to pump into the atmosphere with current technology. Indeed, up until about 200 years ago, the CO2 we've been pumping into the air since we discovered fire has probably been beneficial in staving off a return of massive ice sheets. Its only since the industrial revolution that we've started to tip the scales towards actually warming things up.
All that said, Humans, and any other creatures that evolved during the last ice age, might find it very awkward to deal with a much warmer world. Higher sea levels would drown almost all modern cities, arable land would shift locations, weather patterns would become greatly disrupted, and it would become extremely difficult to feed all six billion of us. So, yes, global warming can be seen as a bad thing from many standpoints, but won't be the end of the world, as I've seen so many folks claim, nor even likely the end of the Human race. In fact, most of those changes are inevitable in the very very long run.
I'm not going to go into most of it, but one of the interesting things that I've known for some time is that CO2 levels have been much higher at some times in the past than they are now. In fact, it turns out that for the vast majority of Earth's 4.5 billion years, CO2 has been significantly higher than it is now, and the Earth has been much, much hotter. The only time in the geologic record where the CO2 amounts have been lower than recent history was during the so-called Snowball Earth period some 650 million years ago, at the dawn of multi-cellular life.
It appears that the most recent ice age (which we are still technically within, although currently enjoying a short-lived interglacial period) was caused by vast amounts of orogeny due to continental collisions, since mountains are one of the major geologic sinks of carbon dioxide. Right now we have the Alps, the Rockies and Himalayas as major mountain chains, and they are all absorbing CO2 as they erode. This is very unusual on geologic time scales.
What does all this mean? Well, it seems that the Earth in general and life in particular are currently in no danger at all from any amounts of carbon dioxide that humans are able to pump into the atmosphere with current technology. Indeed, up until about 200 years ago, the CO2 we've been pumping into the air since we discovered fire has probably been beneficial in staving off a return of massive ice sheets. Its only since the industrial revolution that we've started to tip the scales towards actually warming things up.
All that said, Humans, and any other creatures that evolved during the last ice age, might find it very awkward to deal with a much warmer world. Higher sea levels would drown almost all modern cities, arable land would shift locations, weather patterns would become greatly disrupted, and it would become extremely difficult to feed all six billion of us. So, yes, global warming can be seen as a bad thing from many standpoints, but won't be the end of the world, as I've seen so many folks claim, nor even likely the end of the Human race. In fact, most of those changes are inevitable in the very very long run.
