On March 3/4^th we were lucky enough to attend the ‘Climate Ethics and Economics Workshop’ at Goethe University, Frankfurt. It was an international as well as interdisciplinary event, with a link via Skype to a parallel conference at Duke University. The key note on the first day, broadcast from the US without a single technical glitch, was Geoffrey Brennan. It was Frankfurt’s turn to transmit across the channel on day two, and John O’Neill brought our side of the workshop to a close and raised the curtain on the second day for those the other side of the Atlantic. It would be impossible to sum up all we learnt at the conference, but below are a few key themes that we thought particularly interesting.

One topic that always makes for interesting conversation between philosophers and economists is that of discounting. The debate, stated generally, is about how we ought to weigh the interests of the present against the future. The jumping off point is most often the Ramsey equation, which is an attempt to organise the relevant considerations into a single formula. Two aspects of the discounting debate received the most attention. Kian Mintz Woo’s paper focused on the divisive question of which sort of arguments, from who, we should bring to bear on the different areas of the formula. Certain parameters, Kian argued, might not lend themselves philosophical argumentation and might instead call for a degree of expert elicitation. How we conceive of expertise in this area was, naturally, a bone of contention, and the disagreement made for an intriguing Q&A. In a similar vein, Matthew Randall sought to sharpen our focus on one aspect of the Ramsey equation, this time that of the projected growth rate. Matthew’s concern was that the equation, at least as currently formulated, is not adequately sensitive to low probability catastrophes. His paper was an effort to remedy this oversight. Both presentations on discounting, while very different, reaffirmed how difficult it is to select the specific numerical values for the equation.

Another subject which drew multiple papers was that of geoengineering. Daniel Callies, one of our hosts in Frankfurt, took up a frequently aired worry about such proposals along the lines that they would amount to our ‘playing God’ with the climate. This concern about geoengineering is not always advanced with much precision, though, and the first part of Daniel’s presentation helped to disentangle the different possible ways in which it might be, and is, invoked in these debates. Building on this, the second part engaged directly with some formulations of the objection, casting doubt on at least the most uncompromising, absolutist version of the argument. The second paper on geoengineering, presented by Harald Stelzer of Gratz University, made for an interesting complement. Here the aim was less about trying to assess specific arguments for and against geoengineering than it was about taking a step back and trying to get a clearer sense of the interdisciplinary contours of the field. The picture that emerged was a complex one, and Harald concluded by gesturing toward a multidimensional consequentialist framework that might provide us with some guidance. What both presentations had in common was a call for more subtlety and nuance in our thinking about geoengineering. Given the nature of the topic it is perhaps of little surprise that one finds a polarised and politically charged debate, but both Harald and Daniel warned against viewing it in such all or nothing terms. There are many moral considerations that must be given their due in this context and many different degrees of geoengineering that we might contemplate.

A final aspect of the conference we thought worth flagging up – again of an encouragingly interdisciplinary nature – was the frequency with which economic models were used in the aid of philosophical argumentation. As a case in point, Darrel Moellendorf’s stimulating paper deployed a predictive model as a way to explore the potential implications of his favoured principle of intergenerational equity against Nordhaus’ utility function. By projecting the comparative costs of mitigation from this point forward, Darrel wanted to gain an understanding of where the principles would likely diverge in practice, rather than just in theory. The results were interesting. While Darrel was sold on the theoretical merits of the principle of equity over its utilitarian counterpart, in practice the latter appeared to better spread the costs toward those more able to pay. On the face of it, such a conclusion does not sit well with the egalitarian intuitions that underpin the principle of intergenerational equity. A number of courses of action might follow from this insight and we await Darrel’s completed paper to find out his own full response. A general take home point, though, was that models can provide a valuable aid in helping philosophers understand the implications of their principles over time – especially through facilitating comparisons with alternatives.

Aside from the academic content, the conference was a lot of fun. We are grateful to the Leverhulme Trust for providing us with the opportunity to go and to Normative Orders for their generosity in hosting the event.

By Alex McLaughlin and Joshua Wells, Leverhulme Doctoral Scholars