Sunday, May 11, 2014

A Climate Scientist's Catch-22

This Tuesday, the U.S. government released its third National Climate Assessment, which chronicles the current impacts of climate change in the U.S. The report is full of illuminating graphics and important information (anyone interested should check out the assessment website, linked above, which is very navigable and clear), but the overall message is that the U.S. is already experiencing measurable and attributable impacts of climate change and that the negative impacts greatly outweigh the positive.

After reading news reports on the assessment, a friend emailed imploring me, as a climate scientist and policy fellow, to tell her what we should do about climate change and mobilize our friends to do it.

This is a tremendously difficult question for me: what should we do about climate change? It's a tremendously difficult question for anyone, but climate scientists like myself get caught in an especially troubling Catch-22 when posed with it. My friend was asking about it on an individual level, but it got me thinking about the bigger question of what we as a society should do about climate change and how (if) climate scientists like myself can go about answering that question.

On the one hand, I have scientific knowledge and some policy experience that perhaps allows me unique perspective. This perspective is ostensibly objective, informed by apolitical facts about the way that the climate system and policy structures work. I also have lots of opinions about what we should do about climate change, but these are colored by my personal values regarding tradeoffs I'm willing to make and what I think is important.

Would we trust climate experts' other statements as objective, if they were simultaneously making subjective recommendations based on their personal values? Some argue that climate scientists damage science by advocating policies. But we also so frequently ask climate experts to tell us what to do, and if they are silent then we lose the arguably best informed voice in the conversation. Figuring out how to separate and balance the two is one of the great struggles of being a climate scientist (or an expert in any politicized field). Here's one climate scientist's approach, as well as a back-and-forth on the subject from the New York Times opinion page. I thought myself in circles just clicking between the various articles that other climate scientists have written on the subject.

On the day that the assessment came out, the American Geophysical Union hosted a conference call for its members with some of the key authors of the assessment. Listening in, I was particularly struck by one exchange during the Q&A portion of the call:

One caller rambled for a bit about his favorite method of capturing carbon dioxide before it's released into the atmosphere, before asking the panelists if they had advocated this method in the report. The panelists' response was one that I hear very often regarding assessment reports: the report is intended to be policy relevant but not policy prescriptive, and as such they listed all well-established methods but did not advocate for any particular one. The caller responded tersely with "well, I don't understand what that means" (after which the moderator diplomatically moved the conversation on to the next question), and I think this gets to the heart of an often under-appreciated subtlety of how we deal with climate change.

Climate experts* cannot strictly tell us what we should do about climate change. Climate science tells us what the impacts of climate change are and can tell us how various policy options might do better or worse at mitigating those impacts. Climate economics can tell us how much those various policy options might cost. Climate policy-makers can provide us with a range of policy options. But the choice of which path to take is a fundamentally value-driven question. Depending on what you think is important, you may think we should do nothing to address climate change, everything to address climate change, or anything in between. (Whether what you think is important is defensible or not is another question altogether.)

*I should clarify that, although I hope half-a-decade in the field has given me some advanced understanding, I'm at best en route to being an expert.

In that way, climate experts can tell us what we can do about climate change. But what we should do about climate change is a volatile substance that comes from the combination of what climate experts tell us and what we think is important.

The silver lining is that this theoretically means that accepting the science of climate change does not oblige you to any one course of action. Many people suggest that one of the root causes of climate skepticism, either of the fact that its happening or the fact that it's human-induced, is that skeptics disagree with the courses of action that are often presented as a necessary consequence of the science.

So perhaps this, at least at this point in my ongoing training, is my climate scientist response to the question of what you should do about climate change:
You should understand it--invest honestly and to your best ability in learning the facts behind it, what the impacts are likely to be, what the suggested policy options are, and what their pros and cons are. Resources like the National Climate Assessment website are a perfect way of doing this without trying to get a PhD in it. Then (and only then) you should use your own value system (being honest about what that value system is) to decide what, if anything, should be done about it.

In the meantime, I'll go tell my friend all of my personal opinions about what we should do about climate change.

Sunday, May 4, 2014

Planet A and Planet B

The end of this week found me in a room full of some of the greatest interdisciplinary thinkers around climate change--at a conference on "Historicizing Climate Change." As a sheltered physical scientist, I'm still not entirely sure what "historicizing" means, but the byline of the conference was "How will future historians discuss climate change?"

This question, as difficult as it is to wrap my head around, got me thinking about the really big picture of how we interact with our planet.

Prof. Richard Somerville, a venerable and now retired member of the climate science hall of fame, presented the conference-goers with a thought experiment:

We currently live on Planet A--a planet where we've burned lots of fossil fuels but also happen to have developed really powerful computers and satellites that have enabled climate science to answer a lot of the questions that society is now asking of it.

There isn't necessarily a reason why humanity had to evolve this way. We could be living on Planet B--a planet where we've burned lots of fossil fuels but also didn't invent advanced computing or satellite technology. When this was mentioned at the conference, the image popped into my head of a sort of reverse steampunk world of coal-fueled locomotives and questionable corset choices.


This is an interesting thought experiment to me. Perhaps it is just a lucky coincidence that climate science has "come of age," as Prof. Somerville put it, at the same time climate change pushes society to look to climate science for answers. Then again, society is only asking climate science these questions because climate science itself made society aware of climate change. Theoretically, though, we could have been aware of climate change without satellites or advanced computing--Svante Arrhenius, the 19th century Swedish physicist, theorized the greenhouse effect in 1896, and most of our measurements of longterm increases in carbon dioxide and temperature come from ground-based observations. We just wouldn't have had all the tools we currently have to fully visualize the problem, test our theories, and predict things into the future.

On the other hand, perhaps it was the development of a technology-minded society in which we wanted vast amounts of energy to do things like shoot satellites into space or run giant supercomputing centers that has led to the huge amount of fossil fuel combustion that happens today. Perhaps a society in which we didn't develop things like climate models is also one in which we didn't use fossil fuels heavily enough to create the magnitude of problem that climate models are useful in addressing.

All of this mind-boggling hypothetical musing reminded me of the Anthropic Principle, a pseudo-philosophical idea from astrophysics.

The basic idea of the anthropic principle is that we observe a universe that is well-tuned to our existence because that's the only way we could be here to observe it. For example, if the physical forces in an atom's nucleus were only slightly stronger, hydrogen would have quickly fused into helium in the early universe, and H2O wouldn't exist--a bit of a slap in the face for the emergence of life as we know it...and for the emergence of a consciousness that can question why the physical forces in an atom's nucleus happen to be such that water can exist.

Similarly, perhaps it's completely unremarkable that we happen to have developed a science that allows us to understand one of the great humanitarian challenges of our time, because if that weren't the case we wouldn't be wondering if it's remarkable.

Maybe (probably) this has all just been a completely arcane mental exercise, but it's at least a reminder not to take for granted that we live in a world in which climate science has been more or less able to keep pace with the questions we need it to answer.

We could be living on Planet B instead, and I don't like corsets.