Welcome to 2008, Part 3: Environmentalism Update

Please note the following changes in environmental terminology. Remember, if you get these mixed up, you'll look old-fashioned.

We used to refer to "the hole in the ozone layer." This hole was reputedly caused by certain chemicals (like our dear departed otherwise-non-toxic freon, now replaced by mildly toxic alternatives) which, when released into the atmosphere, would bind with ozone particles and take them out of circulation. The ozone layer is responsible for "absorbing" certain kinds of dangerous radiation from the sun and turning them into "harmless" heat.

At the same time, there were warnings about an excess of "greenhouse gases" and the related problem of acid rain. At the time, the majority of activism was toward reducing emissions of various nasty particles like carbon monoxide, methane, and sulphur. Natural Gas was described as the "clean alternative fuel", because all it releases (when burned efficiently) is carbon dioxide.

Greenhouse gases work like this: the sun's radiation is partly absorbed by the earth, and partly reflected back. Greenhouse gases tend to absorb more of the reflected light, trapping it in the atmosphere instead of letting it escape, thus increasing the temperature.

Ironically, ozone is a greenhouse gas. The "hole in the ozone layer" prevents certain types of radiation from being absorbed and safely converted into harmless heat. Other greenhouse gases absorb other wavelengths of radiation, converting it into dangerous heat. Got it? Good.

We don't talk about the ozone layer or greenhouse gases anymore. Instead, we talk about "carbon emissions," by which we mostly mean "carbon dioxide emissions." Carbon dioxide is what you produce when you breathe. After you clean up your artificial pollution-spewing devices, carbon dioxide is pretty much all that comes out. Other than its contribution as a greenhouse gas, it is harmless.

So the question is: why do we hear so much now about "carbon emissions" instead of "greenhouse gases" in general, or acid rain, or the ozone layer? Is it good news, and the other problems are mostly solved? Or do we as a society just fixate randomly on the most recent problem that someone famous has made a movie about?