Air Pollution versus Climate Change
I recently attended an "off the record" meeting on the subject of energy and environmental challenges. One focus of the meeting was on the role that nuclear power could play in addressing environmental challenges, and that was why I was there. But since the topic was far broader than just nuclear power, turned out to be very instructive to me in revealing some similarities that exist in totally different areas.
Since the meeting was off the record, I can't discuss any of the findings and conclusions of the meeting, and I can't attribute any comments or positions to the individuals who made them. However, some of the discussion referred to information available in the open literature, and that is certainly not off limits. What particularly impressed me was that there were several examples presented that fit well with my observations about unintended consequences, and about the fact that every technology and every activity has some pros and cons.
I usually think of the pros and cons of different energy sources--coal versus nuclear power, renewables versus baseload power, etc. But one of the presenters pointed out that there are analogous tradeoffs within the environmental sphere. In particular, the concern was raised that measures taken to reduce conventional pollution or impacts on the environment could make climate change worse.
The specific example offered at the meeting was that of chlorofluorocarbons (CFCs) and hydrofluorocarbons (HFCs). In the 1970s, evidence began to show that CFCs, which were widely used in aerosol cans and other applications, were damaging the ozone layer in the upper atmosphere, and that this had adverse consequences for human health, particularly deaths from skin cancer. A series of national and international measures taken since then has significantly reduced the use of CFCs, and the evidence is that the ozone layer has rebounded.
The problem is that the CFCs were replaced by other chemicals, particularly HFCs, that we now realize are having other consequences. In particular, it turns out that HFCs are greenhouse gases (GHGs), and may therefore be contributing to climate change.
This is not a breaking news item. When I went to look it up, I found literature dating back several years discussing the problem. But for whatever reason, this particular issue hasn't been on my radar screen lately. When the presenter mentioned it, though, it immediately struck a resonant chord. It was really the same exact story I've been grappling with, in my work and in this blog, for the last several years. It was just a different example. Coal emits carbon, building dams kills fish, nuclear power plants generate radioactive waste, windmills use rare earths, solar arrays take up large amounts of land. (And yes, I know this list is incomplete. I'm just using some examples for illustrative purposes.) And when we try to substitute one energy source for another, we end up replacing one set of consequences with another.
I pointed out to the group that this was a familiar story. I also reminded the participants that some of the early enthusiasm for the automobile, when it was first introduced, was that it would reduce the "pollution" from horses in the city. And when automobiles were few and far between, the tiny amounts of emissions they generated seemed inconsequential, especially compared to the waste from horses that covered the streets of cities. It was only when automobiles multiplied that people realized that they, too, had environmental consequences.
Of course, the observation of the similarity doesn't necessarily offer a good solution, but it does suggest that we need to look at the bigger picture when we introduce new technologies, particularly if our intent is to use them to address an existing problem. Admittedly, people like simple solutions, and this observation clearly acknowledges that there are no simple solutions. While I can't comment authoritatively on the merits of CFCs versus HFCs, in the energy supply field, I know that every technology has its pros and cons. Therefore, we will continue to have to balance cost, reliability, resource use, emissions, and a host of other factors from different energy sources to achieve a solution that best balances out the pros and cons of each energy source.
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