Transitory

I saw a story over the weekend about how the Earth's surface is getting 4% more sunlight than it did a decade ago, because of the reduction in air pollution in recent years, especially in the former Soviet bloc countries. The additional sunlight is believed to be accelerating global warming. I'm confused: We were told that pollution led to global warming so we needed to reduce pollution, but now that pollution is actually being reduced, we learn that also leads to global warming

Perhaps the most interesting thing is that we humans believe that we are the prime movers of global climate change. That's debatable at best. Sunspot activity seems to be a major player, and other long-cycle trends also have major effects. The longest cycle of all is the cycle of multiple long ice ages followed by much shorter interglacial periods over the past two million years or so. The ice ages lasted for an average of about 100,000 years, the interglacials only for about an average of 10,000 years. The current interglacial period has lasted about 14,000 years, so we could be due for another ice age just about any time. Indeed, it may only be human industrial activity and its concomitant "global warming" effect that is keeping us from the next global freeze.

The one thing we can be sure of is that the Earth of the past was very different from what it is like today, and that the Earth of the future will also be very different. Most areas that are dry land today were under water at one time or another in the past. The coastlines of the continents have marched far out and back in again as the sea levels rose and fell based on the amount of water locked up in ice sheets. Indeed, the continents themselves are constantly moving toward and away from each other. Antarctica was not always a frozen continent, and sometime in the future, it won't be again.

We have a hard time really understanding this, because our frame of reference is too narrow. We have a hard time taking the long view. We see things like coastlines as being permanent, because they haven't changed much during our lifetimes. Our lives are too short to see real change on a geological scale.