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Economic Damages from Climate Change

When I tell people I study climate change, sooner or later they usually ask me a simple question: “Is it too late?” That is, are we doomed, by our climate inaction? Or, less commonly, they ask, “But what do we really know?”

With our new paper, Estimating Economic Damage from Climate Change in the United States, I finally have an answer to both of these questions; one that is robust and nuanced and shines light on what we know and still need to understand.

The climate change that we have already committed is going to cost us trillions of dollars: at least 1% of GDP every year until we take it back out of the atmosphere. That is equivalent to three times Trump’s proposed cuts across all of the federal programs he cuts.

If we do not act quickly, that number will rise to 3 – 10% by the end of the century. That includes the cost of deaths from climate change, lost labor productivity, increased energy demands, costal property damage. The list of sectors it does not include– because the science still needs to be done– is much greater: migration, water availability, ecosystems, and the continued potential for catastrophic climate tipping points.

But many of you will be insulated from these effects, by having the financial resources to adapt or move, or just by living in cooler areas of the United States which will be impacted less. The worst impacts will fall on the poor, who in the Untied States are more likely to live in hotter regions in the South and are less able to respond.

Economic damages by income deciles

One of the most striking results from our paper is the extreme impact that climate change will have on inequality in the United States. The poorest 10% of the US live in areas that lose 7 – 17% of their income, on average by the end of the century, while the richest 10% live where in areas that will lose only 0 – 4%. Climate change is like a subsidy being paid by the poor to the rich.

That is not to say that more northern states will not feel the impacts of climate change. By the end of the century, all by 9 states will have summers that are more hot and humid than Louisiana. It just so happens that milder winters will save more lives in many states in the far north than heat waves will kill. If you want to dig in deeper, our data is all available, in a variety of forms, on the open-data portal Zenodo. I would particularly point people to the summary tables by state.

Economic damages by county

What excites me is what we can do with these results. First, with this paper we have produced the first empirically grounded damage functions that are driven by causation rather than correlation. Damage functions are the heart of an “Integrated Assessment Model”, the models that are used by the EPA to make cost-and-benefit decisions around climate change. No longer do these models need to use out-dated numbers to inform our decisions, and our numbers are 2-100 times as large as they are currently using.

Second, this is just the beginning of a new collaboration between scientists and policy-makers, as the scientific community continues to improve these estimates. We have built a system, the Distributed Meta-Analysis System, that can assimilate new results as they come out, and with each new result provide a clearer and more complete picture of our future costs.

Finally, there is a lot that we as a society can do to respond to these projected damages. Our analysis suggests that an ounce of protection is better than a pound of treatment: it is far more effective (and cheaper) to pay now to reduce emissions than to try to help people adapt. But we now know who will need that help in the United States: the poor communities, particularly in the South and Southeast.

We also know what needs to be done, because the biggest brunt of these impacts by far comes from pre-mature deaths. By the end of the century, there are likely to be about as many deaths from climate change as there are currently car crashes (about 9 deaths per 100,000 people per year). That can be stemmed by more air-conditioning, more real-time information and awareness, and ways to cool down the temperature like green spaces and white roofs.

Our results cover the United States, but some of the harshest impacts will fall on poorer countries. At the same time, we hope the economies of those countries will continue to grow and evolve, and the challenges of estimating their impacts need to take this into account. That is exactly what we are now doing, as a community of researchers at UC Berkeley, the University of Chicago, and Rutgers University called the Climate Impacts Lab. Look for more exciting news as our science evolves.

Probabilistic Coupling

Environmental Modelling & Software has just published my work on a new technique for coupling models: Probabilistic Coupling. My thoughts on coupled models had been percolating for a couple years, before a session at the International Conference on Conservation Biology in 2013 offered me a chance to try it out.

Probabilistic coupling has three main goals:

  • Allowing models to be coupled without distortionary feedback
  • Allowing multiple models to inform the same variable
  • Allowing models to be coupled with different scales

With these three features, the very nature and approach of coupling models can change. Current model coupling requires carefully connecting models together, plugging inputs into outputs, and then recalibrating to recover realistic behavior again. Instead, this allows for what I call “Agglomerated Modeling”, where models are thrown together into a bucket and almost magically sort themselves out.

The code for the model is available within the OpenWorld framework, as the coupling example.

Torch passing

A friend: “The big story in the world this week is… the inevitable passing of the torch. We will witness the beginning of a new era this week, I feel.”

Naturally, he was only using the French election (NYT: “The result was a full-throated rebuke of France’s traditional mainstream parties, setting the country on an uncertain path”) in jest to refer to something completely unrelated, but it gave me a thought. Much as I love some parts of globalization and the Post-WWII international institution, this is a passing of the torch. And that uncertain recipient of the torch– maybe populist, maybe bigoted, maybe urban, technophilic, and progressive– that recipient is us.

Every generation seems surprised when the torch is passed in their lifetime, but it cannot be otherwise.

LJ blasted about its 18th birthday, of which I had apparently been part 13.55 years, and posted 473 times. I guess it was time to move on.

Next stop: London

My time at UC Berkeley is drawing shut, and for the past 4 months I have been pursuing my own eclectic version of the academic job market. I find myself squarely between economics, geophysics, and data science, with disconnected bits to show from a tough-to-articulate whole. But I have also been fortunate to have strong supporters, who appreciate whatever it is that I do. With their help, the job search has treated me well, and forced me to decide between excellent and incomparable alternatives. So, this is a post of victory!

Each of my five fly-out interviews required distinct presentations, across them covering papers on fisheries, coffee, and climate, a teaching talk on thermoeconomics, and a pitch for a new sustainability program. I interviewed at science, economics, and interdiscplinary departments, and got the support of the faculty at every one. Flame and I just finished a revisitation of the top US options, to decide on our new home.

But across professional fit, cultural metabolism, Flame’s opportunities, and the politrumpal climate, we realized that the best choice was none of them: I am taking a 100% research assistant professorship at the Grantham Research Institute on Climate Change and the Environment at the London School of Economics! LSE is in the heart of London, which is also home to Flame’s nonprofit.

There I can look forward to a huge pool of potential collaborators, including two from my PhD program. LSE straddles the divide between the US academic world, where I will be able to keep my collaborations alive, and the European world of modeling and proaction that I have always been drawn to. The advertised position was for “Growth and the Environment”, which I’m all about. And connecting science with policy is part of the job, with a team at hand specifically for this purpose.

I move there at the beginning of 2018. Between now and then, I have 4 more months at Berkeley, and in July I start a mini-postdoc-#2 at the University of Chicago.

I can’t wait to set up in a new continent, and hope you all come to visit!

All work and play, Day 5

Another back-dated day from the Balkans Trip, originally at

It was gloriously sunny, the perfect day to explore the town of Mostar on my own.  I got lost and then found again, crossed five bridges (in both directions), read a book and composed several post cards.  I did not, however, consume my required 3 espresso-based drinks.

James fastidiously programmed away save a lunch and dinner break where we enjoyed waterfront dining and fantastic Italian-inspired food, respectively.

In the hours between sunset and pitch black, we explored Počitelj, an Ottoman Empire fortress with an incredible amphitheater, sizable mosques and steep staircases. Attempting photos in the dark proved fruitless, so we ventured back to Mostar and enjoyed a very good dinner at Restaurant Schumann. I suggest if you in town, you take the mile plus walk to this harbor of home-made pasta, breads and local charm.  No tourists.

One culinary observation: we always get the “basic” bread when we sit down (part of the 2 euro per person cover charge). Other diners get some version of a grilled thick pita bread.  I’ve asked for the local bread, and then received a side of cold, deflated pita.  Moreover, when I request garlic (another of my daily requirements), I get whole, raw cloves, which I do my best to macerate with a butter knife. More words to learn.

Tomorrow, we will mobilize to Dubrovnik, where our plans and expectations of Croatia await.

I ❤ small towns, Day 4

Another back-dated day from the Balkans Trip, originally at

Today, we decided to go to Bosnia. The drive from Montenegro to Bosnia provided stunning views of the bay, snowcapped mountains, vocal yacks, and sacks of potatoes for sale by the side of the road. We took the long way ‘round, with the prettiest of views (cue song lyrics), following the serpentine shore of the Bay of Kotor. The bay narrows into a strait, flowing into an upper bay, with an island monastery sitting at its mouth. All around the bay are jutting cliffs, with terracotta roofs in isolated hamlets. We climbed through strings of tunnels and Old-Western style homesteads, before coming to the vineyards of Bosnia.

Crossing the border was pretty easy, with no bribes needed. The green card we purchased through the rental car agency seemed to do the trick. We approached the tiny town of Mostar (which I still want to call monster…) three hours later.

Mostar pulls at heart strings with its picturesque bridges and stone-lined streets.  To seal the deal on its delights, our boutique hotels provides unlimited cookies for James.  By driving through the vertical and tiny streets—as we saw on a sign earlier— “you risk your life”. But now settled, we plan to stay two nights so that tomorrow can be spent with my purchasing of hand painted decorative items (Turkish style) and James making climate models (computer style).  We are both helping the world, I reckon.

This evening we strolled along the dividing river, where locals were watching football and filling time during the “low” season.  Observation: men and women seem to run in separate groups.  Not in the forcibly gender segregated way we saw in Egypt, but far from the coed peer groups you get in the US.

I love that wifi is available virtually everywhere here, so if any on you darling readers have an iPhone, it’s free to message and facetime me, and I would love that tomorrow (Note the 5 hour time difference ahead of EST).

Chiseled features, Day 3

Another back-dated day from the Balkans Trip, originally at

It’s Wednesday so we must be in another country…

We flew to Tivat, Montenegro and rented a car (with limited challenge but moderate wait for the car to arrive) from now through Sunday. Our first stop is the picturesque Bay of Kotor. It was drizzly and cold when we arrived, but we left the car safely (if expensively) at a car park and ventured into the walled city on foot to find our centrally-located hotel in the winding streets.

Kotor is a city covered in beautiful white and tan stone: the streets are tiled, the water drains are carved, the churches and homes are built of huge, sturdy blocks. Shops and caffes sprout shingle signs, carefully branded for the onrush of tourists that will arrive by yacht in May. The mountain rises with water-sculpted towers, looming imposingly behind the city, with the city wall snaking along its highest ridges.   Montenegro feels like a more cloistered Greece; they also use the Euro but seem to resent it.

As the light waned, James thought it would be a great idea to explore the step mountain—on foot. When I protested, he conceded that we could drive. At a 70 degree slope, we were greeted by 25 hair pin turns. I backed down—from several cars—and then out–when it became pitch black and the Bay sneered bellow, reflecting the schizophrenic headlights of cars that took the curves at 100 kph.

We decided to find our way back on safer roads, and selected the Stari Mlini ( for dinner. Named for the working water wheel on the far side of the Bay, we enjoyed stunning salads, clay-oven-prepared eggplant and local octopus. The dining room was warmed by a fire and we were the sole “seasonal” dinners at 8pm. The chardonnay made 50 km away was not unpleasant.

Back in the car, we zoomed to the hotel so James could do some calls (translate: be on the computer for the next 4 hours) while I explored the night life in town. I sampled the local rose and red wines, and for young grapes, they outshine VA productions. I happened upon a Bollywood style music video production underway, where the singers were dressed as jesters and Princess Jasmine. The taping concluded with some well positioned fireworks that illuminated the fortress walls. I also passed the youth hostel, where I head a smattering of German and a sole American voice complaining about Adweek and LA.

Tomorrow, we plan to enjoy the free breakfast and then head to Mostar, Bosnia, and perhaps reconsider the treacherous drive into the hills of the Adriatic coast.

NB: A note on the format of these blogs: I write steam of conscious observations then James edits for accuracy (i.e. spelling of locations) and adds alliterative adages (self-explanatory and excruciating). Please submit your comments, c/o the Internet to us.

Sad to leave Novi Sad, Day 2

Another back-dated day from the Balkans Trip!

Happy Pi Day!

Goal: consume as many Serbian pies as possible today.

We started at a lovely coffee shop providing extensive chemistry lessons on coffee composition and bean varietal. James had a Nutella croissant, which he counts as pie number one of the day.

Took a bus 1.5 hours to the northwest of Belgrade to the darling town of Novi Sad where we had a fantastic meal at Fish & Zelenish (, feasting on baked feta, sizable salads and salmon tar-tar above an open kitchen. They gifted us a cookbook/menu and regional salt. No pie was consumed, but we somehow were not feeling deprived. It was definitely the best meal we’ve had so far.

We wandered the dense old town, of tiled streets and artist resalers. Found a swanky hotel to take some work meetings/calls and make arrangements for tomorrow. Amended plan includes flying into Tivat, Montenegro and renting a car to explore the coast. Why Tivat? Oh, tickets are only €60, compared to €250 flights or 12 hour buses to go half the distance.

Dinner was a very late, with an overpriced excursion to the Opera/restaurant. Sitting in a plush overhead booth, with a silent bell tassel to call the waiter, we order ambergine with raw garlic and baked goats (cheese). Alas, after hours, the music was recorded and the kitchen too early shuttered.

The day in numbers:

  • Pies consumed: 0.314
  • Ratio of time on train to time on bus to cover the dame distance: 1.8 to 1
  • (Took the bus to Novi Sad, and the train back. The price was the same, time spent was not).
  • Jewish historical sites visited: 2
  • Post cards sent: 3
  • Bread products sampled: 6
  • Churches seen: 14
  • Enclosed spaces with smoking: 100% minus Fish & Zelenish.

Science and language

One of the rolling banners at last year’s meeting of the American Geophysical Union had a scantly-clad woman and the words “This is what most people think of as a ‘model’”. See, scientists have a communications problem. It’s insidious, and you forget how people use words and then feel attacked when you have to change how you speak.

I have a highly-educated editor working with me on the coffee and climate change report, and she got caught up on a word I use daily: “coefficient”. For me, a coefficient is just a kind of model parameter. I replaced all the uses of “coefficient” with “parameter”, but I simultaneously felt like it dumbed out an important distinction and wondered if “parameter” was still not dumbed down enough.

AGU has a small team trying to help scientists communicate better. I think they are still trying to figure out how to help those of us who want their help. I went to their session on bridging the science-policy divide, and they spent a half hour explaining that we have two houses of congress. Nonetheless, it is a start, and they sent us home with communication toolkits on USB. One gem stood out in particular:

So I will try to reduce the ignorance and political distortions of my devious communication plots, until I can flip the zodiac on this good response loop. Wish me luck.

Tropict: A clearer depiction of the tropics

Tropict is a set of python and R scripts that adjust the globe to make land masses in the tropics fill up more visual real estate. It does this by exploiting the ways continents naturally “fit into” each other, splicing out wide areas of empty ocean and nestling the continents closer together.

All Tropict scripts are designed to show the region between 30°S and 30°N. In an equirectangular projection, that looks like this:


It is almost impossible to see what is happening on land: the oceans dominate. By removing open ocean and applying the Gall-Peters projection, we get a clearer picture:


There’s even a nice spot for a legend in the lower-left! Whether for convenience or lack of time, the tools I’ve made to allow you to make these maps are divided between R and Python. Here’s a handy guide for which tool to use:


(1) Supported image formats are listed in the Pillow documentation.
(2) A TSR file is a Tropict Shapefile Reinterpretation file, and includes the longitudinal shifts for each hemisphere.

Let’s say you find yourself with a NetCDF file in need of Tropiction, called bio-2.nc4. It’s already clipped to between 30°S and 30°N. The first step is to call to create a Tropicted NetCDF:

python ../ subjects/bio-2.nc4 ../bio-2b.nc4

But that NetCDF doesn’t show country boundaries. To show country boundaries, you can follow the example for using draw_map.R:


## Open the Tropicted NetCDF
database <- nc_open("bio-2b.nc4")
## Extract one variable
map <- ncvar_get(database, "change")

## Identify the range of values there
maxmap <- max(abs(map), na.rm=T)

## Set up colors centered on 0
colors <- rev(brewer.pal(11,"RdYlBu"))
breaks <- seq(-maxmap, maxmap, length.out=12)

## Draw the NetCDF image as a background
splicerImage(map, colors, breaks=breaks)
## Add country boundaries
## Add seams where Tropict knits the map together

Here’s an example of the final result, for a bit of my coffee work:


For more details, check out the documentation at the GitHub page!

And just for fun, here were two previous attempts of re-hashing the globe:


I admit that moving Australia and Hawaii into the India Ocean was over-zealous, but they fill up the space so well!


Here I can still use the slick division between Indonesian and Papua New Guinea and Hawaii fits right on the edge, but Australia gets split in two.

Enjoy the tropics!