I had a long conversation this week with a friend of mine who is something of an expert on climate change. He noted that since the hacked email brouhaha, in which some climate experts were seen discussing ways to keep their opponents from publishing, there has been a little spate of anti-global warming articles in top journals, including Nature Geoscience. The publicity, he suggested, has led journal editors to strive for a little more balance. And note that there is no shortage of credentialed scientists who are trying to publish anti-global warming articles.
My position remains the same, that we are doing a gigantic experiment with the atmosphere. We have no idea what will happen if we keep pouring CO2 and methane into the air, but there is a good chance it will be very bad. Since there are also lots of other reasons to move away from a fossil-fuel based economy, I think alternative energy is the way to go. I also think that even modest sea-level rise could be a catastrophe for our species, since there are so many of us crowded into low-lying areas.
My friend believes very firmly that greenhouse gases will warm the planet significantly. He wonders, though, if this might be the only things saving us from a new ice age. As he noted, the general trend of climate over the past 2 million years has been colder and colder. On average, the ice ages have gotten colder and longer, the warm periods less warm. So without human intervention, he suspects that we might already be on our way back into a grimly cold age.
The earth has no normal, baseline climate. At times in the past it has been much warmer than it is now, at times much colder. We do not understand why the climate changes, although we know that the level of CO2 in the air plays a part. I take all that as a reason to be very careful with the planet as we know it, but it can also be taken as a reason for confidence: whatever happens to the climate, life will survive, and we almost certainly will, too.