Hyper-local climate impact forecast, finally

A study published in Science at the end of June should have found its way onto the front pages and screens of every community newspaper and local news program in the country. But it didn't. At least, not around these parts. Which is a shame, because it's precisely the kind of story we've been waiting for all these years. (Apologies to the spirit of Douglas Adams). I'll do my best to rectify the oversight.

In "Estimating economic damage from climate change in the United States," a team of researchers led by Solomon Hsiang, who specializes in public policy at the University of California, Berkeley, applied the latest datasets on expected damages we can expect because of what we're doing to the planet to the economy. On average, they calculated that the U.S. would lose about 1.2% of its GDP for each degree centigrade (1.8 °F) the Earth warms. But we already knew that level of damage -— lost crops, coastal erosion, heat deaths and so forth — was in the pipeline. What's interesting is that the team also produced specific forecasts for each county.

For the first time, we've been offered at least a rough idea of what fossil-fueled business as usual will cost us, at home. We're not just talking about polar bears anymore. It's now about jobs, wages, infrastructure, crime. Any news outlet that's paying attention should have jumped on this. There's even a handy-dandy interactive map:

You can zoom in on any county (even Hawai'i and Alaska). For example, Polk County, NC, where I live, is expected to lose about 7% of its economy due to the various effects of climate change. Of course, it's a very coarse estimate, and one that's based on the assumption that we make no significant policy changes to mitigate the anticipated effects. No one really believes that particular outcome is likely — just look at how fast the costs of solar panels and wind turbines are falling, or how rapidly Elon Musk's little car company has become more valuable than GM. But the exercise is valuable because business as usual is the only baseline we have for which the elements are known precisely. And then there's Donald Trump, so ...

There are two other points worth thinking about. First, there's this depressing observation:

Combining impacts across sectors reveals that warming causes a net transfer of value from Southern, Central, and Mid-Atlantic regions toward the Pacific Northwest, the Great Lakes region, and New England (Fig. 2I). In some counties, median losses exceed 20% of gross county product (GCP), while median gains sometimes exceed 10% of GCP. Because losses are largest in regions that are already poorer on average, climate change tends to increase preexisting inequality in the United States.

Once again, the South and the poor get the short end of the stick. This is mostly because the harm associated with hotter summers in the South will be more deeply felt than the benefits of slightly warmer winters up North.

Second, although the data are only presented by county, you can actually extract even more localized information by giving the map a close look and considering the surrounding geography. In the case of Polk County, the low-elevation foothills of the the county's eastern parts will almost certainly be responsible for most of the anticipated decline in gross county product, because it's where most economic activity and the lion's share of the population are concentrated, and also because the higher-elevation western side is next door to even higher-elevation counties (Henderson and Buncombe), where the predicted impact is negligible. Which means my home town of Saluda, which is geographically more connected with the mountains than the foothills, will probably do better than the rest of the county.

Speaking of avoiding the really bad stuff, it's almost poetic justice that, as employees of NOAA's National Centers for Environmental Information in Asheville, the seat of Buncombe county, many of the scientists responsible for cranking out the climate data on which this study relies happen to live in a part of the world that is not expected to suffer too much. At least not in the next few decades. Sooner or later, of course, everything will go sideways.