(This will be the first in a series of blog posts on carbon emissions, their costs and implications for Maine, and existing and proposed policy prescriptions.)

Last week, an article made the rounds entitled “the social cost of carbon“. This is of special interest to me right now, because I recently began teaching Environmental Economics at the University of Southern Maine. (Being a professor used to be my full-time job. Now I’m an economic and sustainability consultant, but teaching that class one day a week keeps me up to date on the most recent articles in my field.)

The concept of “social cost” in economics is nothing new, of course.  Economists have long recognized that the production and consumption of certain goods produces negative externalities, or costs imposed on “third parties” who are not directly involved in producing or purchasing that good.  Such externalities can be called social costs, and while it’s difficult to measure such social costs, environmental economists do their best (see, for example, my recent blog post on ecosystem services).

So why this new article on the social cost of carbon, and why is it taking on a new importance now? Because the social cost of carbon has now been upheld by a federal appeals court.

The details of the case are not particularly important for our purposes here. Suffice it to say that, every time a federal agency imposes a regulation, they are required to demonstrate that the benefits of the regulation exceeds the costs.  This particular case was about improving the efficiency of commercial refrigeration equipment.  But if the government (in this case, the Department of Energy) wants to tighten efficiency standards, they need to show that the costs of meeting the new efficiency standards aren’t exceeded by the benefits.

The costs of meeting the proposed standards are relatively easy to calculate. Refrigeration equipment companies might have to use new technologies or inputs, which are presumably more expensive than current methods. But how to calculate the benefits of tighter energy standards?  Enter the social cost of carbon.

The social cost of carbon is, according to the EPA, “meant to be a comprehensive estimate of climate change damages and includes, among other things, changes in net agricultural productivity, human health, property damages from increased flood risk and changes in energy system costs.” Yet the EPA admits that the social cost of carbon does not include all damages, because “of a lack of precise information on the nature of damages and because the science incorporated into these models naturally lags behind the most recent research.”

The economic and scientific calculations that went into arriving at  the social cost of carbon are mindboggling. The estimates used three well-known (well, well-known in certain circles) integrated assessment models that consider the linkages between climate processes and economic growth. These models translate emissions into atmospheric greenhouse concentrations, from there into changes in temperature, and finally from there into economic damages.

It is an ambitious undertaking, and some would say an impossible one. There are so many uncertainties in any step along that chain. For example, the models are ill-equipped to deal with non-linearities or “tipping points.”.  In addition, the damages from an additional unit of CO2 is unlikely to have a linear effect (as a price per ton of carbon would imply), but increase as more carbon is emitted into the atmosphere. Dealing with future costs is difficult as well, as it involves “discounting the future,” a sticky ethical and legal problem as well as an economic one.

I am of the school of thought that “some number is better than no number.” Yes, the social cost of carbon as it stands now is highly imperfect and probably a gross under-estimate of the full social damages caused by a ton of carbon dioxide in the atmosphere.  However, it is better than assigning a cost of zero, which would be the implicit price had the social cost of carbon not been considered.

This blog is supposed to focus on the links between the economy and the environment in Maine. So far this blog post hasn’t done that – but be  patient!. The next blog post will focus on some of the possible solutions in terms of mitigation of climate change via a tax or a trading scheme (specifically for Maine), and the last will sketch out what’s at stake for the state. Stay tuned!