Nitrous oxide has always been a normal part of our atmosphere, "but since industrialization, its concentration has been going up," says A.R. Ravishankara at the National Oceanic and Atmospheric Administration in Boulder, Colo.
Now that synthetic chemicals are waning in the atmosphere, he wondered if other gases posed any environmental threat. As he reports in the online edition of Science magazine, nitrous oxide, a byproduct of agriculture, is a serious problem for our planet.
"There's so much being emitted, that right now, nitrous oxide emissions would be the largest ozone depleting gas emissions today, and it will continue to be in the future," Ravishankara says.
Unmentioned is the fact that there will always be some chemical that is the largest ozone depleting gas in the atmosphere. The real question is how big a problem this might be.
Ravishankara estimates that by the end of the century, we will have 4 percent less ozone in the stratosphere than we would have had before the Industrial Age, as a result of nitrous oxide.
Note the careful language: 4% less than before the Industrial Age, not less than we have right now. Total ozone depletion right now is about 3% compared to pre-1980 values. So the effect of nitrous oxide is no more than 1% over the next 90 years.
At this point the correct response, it seems to me, is sufficient interest among atmospheric scientists to keep an eye on things, and yawns and a return to our normal lives for pretty much everyone else. Looks like there's no disaster on the way. NPR doesn't take this approach, of course:
"I think that limiting nitrous oxide is going to be more difficult than, for example, limiting carbon dioxide emissions. And we know how difficult that is," she says.
That's because we need nitrogen - it's an essential part of protein. Carbon dioxide comes mostly from smokestacks and tailpipes.
"You can get your energy from other sources than carbon, but you really can't get your food from sources other than nitrogen."
We can't phase out nitrogen fertilizers, Nevison says. And studies show we could make only a modest difference if we used them more carefully.
And it's not just the ozone layer that's at issue here. Nitrous oxide also contributes to global warming - so there's another important reason to pay attention to this often neglected gas.
The implicit assumption here is that since some harm is measurably taking place, therefore we must pursue any means to mitigate it. But should we even bother trying to limit nitrous oxide emissions at the present time? This really should be an open-and-shut case: the effect is very small, the cost is very large. The faithful in the religion of environmentalism will try to persuade us that it doesn't matter, of course: Sin is being committed, therefore it must be stamped out, regardless of cost. That last sentence is particularly telling. If your case for environmental danger isn't strong enough otherwise, then by all means bring in the big gun: global warming.
The biggest problem with environmentalism (as a movement) today is that costs and benefits are never netted out. Bjorn Lomborg attempted to apply this kind of economic analysis and was summarily excommunicated for it. The IPCC does this kind of analysis on global climate change, but the results are so mild that they get no media coverage and environmentalists pretend they don't exist (or argue that the IPCC has been bought, or some such conspiracy). We should certainly take some steps to protect the environment, but people have other needs, wants, and values as well.
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