Catastrophe Ethics

Chapter 1

The Climate Case

It is worse, much worse, than you think.

-David Wallace-Wells, The Uninhabitable Earth

I'd love to retire in Cyprus. It's as close to paradise as anywhere I've ever been, with long stretches of largely unspoiled beaches, warm Mediterranean water, mild winters, friendly people, and amazing food. My partner, Sadiye, is Turkish Cypriot (from the northern half of the island), and so we have a home there, full of people who love us. I love the Turkish language and the culture, and every time we go home, we wonder how long it will be until we can just stay there.

Unfortunately, I don't think we'll retire in Cyprus. Not year-round, anyway. It'll just be too hot.

Since it's an island sitting at the intersection of the Mediterranean, the Middle East, and Africa, you might expect it to be a warm climate. And that's how it used to be. But it's going from reasonably warm to unbearable in the summer months.

Among the hundreds of Cypriots I've met since my first visit in 2003, I've never encountered climate denialism there. There's not much room for doubt when the older generations have seen the environment go from hospitable, though warm, to downright hostile for two to three months of the year. Indeed, my in-laws regularly tell me about how much change they've seen in their lifetimes. Even when Sadiye was growing up, families largely didn't invest in expensive air-conditioning units (which use very expensive energy). She and her brother grew up sweating at night during the summer because it was at least possible to get away with forgoing A/C units in the children's rooms.

Not anymore. Every Cypriot home I go to now has A/C units in every bedroom, and most have the (prohibitively expensive) large units in their living space to get them through the worst of the summer months.

By the time Sadiye and I intend to retire-somewhere around the midcentury mark-I don't think we'll want to be in Cyprus for a good chunk of the summer. Of course, many Cypriot people will still live on the island, but it will be getting more uncomfortable to do so (and they will likely have increased the already prevalent tendency to simply go on holiday in August to escape the heat). My family and friends already have modified work schedules during the heat of the summer, which encourage people to stay indoors and find air conditioning during the hottest part of the afternoon. Construction and other manual labor slows down or stops. Those without air conditioning or who can't afford to run it constantly struggle to stay not only comfortable but healthy.

In fall 2021, it was announced that August of that year had been the hottest month ever recorded in Cyprus. High temperatures averaged 39.8 degrees Celsius (103.6 degrees Fahrenheit), with a single-day high temperature of 44.3 degrees Celsius (111.74 degrees Fahrenheit). To see how quickly things are changing, consider that the average high temperature in August from 1981 to 2010 was 37 degrees Celsius (98.6 degrees Fahrenheit). And warming trends are only speeding up. Every Cypriot I have spoken to about climate change is deeply concerned about the future, as anyone my age or older has viscerally felt the dramatic change over their lifetimes.

When I was growing up and first learned of climate change, the wisdom of the day was that it occurred on a time scale too slow to notice. That was part of the challenge, in fact, that we needed to address a threat that one couldn't actually see over the course of a lifetime. But we've now come to realize that's simply not true, and we're already seeing the changes. People like me who spend our lives thinking about this issue will tell you: we make very practical decisions based on the future that climate change is ushering in.

Cypriot summer during my sunset years isn't the only time and place I'm avoiding. During the summer of 2020, it seemed like the entire West Coast of the United States was ablaze. Residents of California couldn't go outside due to air-quality warnings, and pictures of the San Francisco Bay Bridge were all over the internet, standing against a threatening, apocalyptic-looking orange sky. Fire season is spreading dramatically in California, both in duration and intensity. There is much that Sadiye and I love about the Bay Area: the weather; a strong biotech presence for her (she's an industry scientist); a thick network of universities for me. But my climate angst won't let us entertain the idea of moving there.

Unsurprisingly, another restriction on our future plans is that we avoid moving too close to the ocean. Living on the East Coast, moving somewhere along the eastern shoreline of the United States seems almost attainable. But the increasing number and intensity of tropical storms, along with sea-level rise, has me acutely aware of the ever-increasing costs (both financial and anxiety-related) of those beautiful water views. Iconic beach destinations like the Outer Banks in North Carolina are slowly being lost to the Atlantic Ocean, with beachfront homes now regularly falling into the rising waters and the only highway into the area constantly requiring protective adaptation (and a section of it being converted into a bridge, for a price tag of $155 million).

Miami-Dade County is perhaps in an even more dire circumstance, sitting on porous limestone on the low-lying southern tip of Florida. There, the phenomenon of "sunny-day flooding," which is flooding just from high tide, has become a standard nuisance, forcing the city to spend hundreds of millions of dollars in an attempt to prolong its life. According to the National Oceanic and Atmospheric Administration, the same story is playing out in coastal communities around the world. But adaptation efforts like seawalls, beach nourishment, building houses on stilts, and converting roads to bridges are Band-Aids. Low-lying coastal areas will eventually be overtaken by rising waters while being ever more routinely battered by ferocious storms.

If you're wondering whether it's a bummer to live with someone who spends their days thinking about climate change, Sadiye is probably too nice to say yes but too honest to say no.

Of course, much of this caution is based on predictions. Yes, Cyprus is already hotter, and yes, Miami has a "King Tide" season. But my worry that it will continue to worsen to a degree that should make most of us want to stay away is based on projections. So couldn't I be wrong? After all, we're hearing all the time about climate summits, new policies and pledges made by various countries, and green technologies that are supposed to revolutionize our future.

Perhaps, then, I'm just being pessimistic. Humanity is going to figure this out, right? After all, the Netherlands figured out how to protect itself against the sea. When we realized that our collective actions were causing a hole to appear in the ozone, we moved quickly to adopt policies and change behaviors in a way that solved the problem. Surely we'll eventually pull off something similar when it comes to climate change. Right?

I want to tell you yes. I want to say that there's still hope that we will avoid the sort of future I fear. But while there's a technical sense in which we could, it's not realistic. Serious harms are already here, many more are coming, and we avoid talking about them at our peril.


For hundreds of thousands of years, the atmosphere was relatively stable in an important respect: the proportion of greenhouse gases (GHGs) such as carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) remained within a certain range. That’s important because these gases are very efficient at trapping heat, so when the concentration of GHGs in the atmosphere goes up, less heat is able to escape from Earth out into space and so the global average temperature increases. The atmosphere is like a blanket that keeps the Earth warm (this is good up to a point, since without it, the planet would be an icy, lifeless rock), and we can add insulation to that blanket by emitting more heat-trapping gases into it. Although all GHGs contribute to climate change, CO2 gets the most attention, as it is the primary GHG emitted by humans; in the United States, it constituted 79 percent of all GHG emissions in 2020.

Prior to the Industrial Revolution, the atmospheric concentration of CO2 was around 280 parts per million (ppm), but the development of the world's postindustrial economies resulted in two changes in human behavior that had profound effects on the climate. First, it massively increased the amount of CO2 we spew into the air (primarily through the burning of fossil fuels). And second, it reduced the planet's resources for dealing with that excess by engaging in practices like clear-cutting forests, destroying peatlands for agricultural or other purposes, and generally going about stripping the natural world and replacing it with a built one. These forests and peatlands that we've eliminated make up some of the world's most important "carbon sinks," which is one of the ways in which carbon is removed from the atmosphere.

So we've both filled the air with CO2 and limited the planet's ability to regulate atmospheric concentrations.

The result is that the atmospheric concentration of CO2 has been steadily climbing since the Industrial Revolution, with mean global temperatures right behind it. Although the science of climate change has been recognized for hundreds of years, the severity of the situation began to come to public attention in the late twentieth century, with the fundamental question being: How warm can we allow the planet to get before it causes serious, irreversible harm? And the important follow-up: How much CO2 can we release into the atmosphere and stay below whatever that threshold is?

Although many took that first question to be a scientific one (involving predictions about the effects of warming on human populations), it's actually a moral one. We needed to know what the costs of warming were, and to whom, so that we could draw a line at some point and say that it would be wrong to let a certain amount of damage happen.

The answer that evolved and began to gain consensus at the end of the twentieth century was that we must keep warming below 2 degrees Celsius (global average). This number first appeared in a publication by Yale economist William Nordhaus in 1975, and slowly seeped into the scientific and political reasoning over the following two decades. In 1996, a limit of 2 degrees was cemented in policy aspirations by the European Council of Environment Ministers, which stated, "Global average temperatures should not exceed 2 degrees above pre-industrial level."

The answer to the second question took longer to answer. What must the human population do in order to prevent 2 degrees of warming? There is significant uncertainty here, but it looks like we can do that by keeping atmospheric CO2 below 450ppm. Using this number, scientists were able to calculate an all-time, anthropogenic (human-caused) carbon budget. That is to say, there is a certain amount of carbon that we can emit if we want to stay below that 450ppm threshold, thus avoiding 2 degrees of warming. That number? One trillion tons of carbon, or approximately 3.67 trillion tons of CO2.

A trillion metric tons. The number 1 with twelve zeros after it. An unbelievably large amount of something unimaginably small.

That's the budget humanity was given.

Despite the sheer magnitude of that number, we were quickly approaching it. Already in 2009 when the budget was first proposed, it was calculated that humanity had used more than half of it, and global emissions were still speeding up. Worse was the fact that 2 degrees' warming was not a goal that we should want to hit. Scientists and politicians drew a line in the sand at 2 degrees warming, claiming that we should never cross that threshold; but that does not mean that it would be a good place to land. Two degrees' warming is not what we can allow without causing harm; it's what we can allow without causing massive harm at a magnitude that is essentially irreversible on a human time scale.

As a result, some scientists and activists began claiming that we had answered the moral question incorrectly: 2 degrees' warming is too lax; we should have aimed to prevent warming from exceeding 1.5 degrees Celsius. No one thought that limiting warming to 2 degrees would prevent harm, so we should look at who would be harmed if the planet were allowed to warm 2 degrees. And the answer, unsurprisingly, was that the world's poorest and most marginalized would be hit first and worst, with the globally privileged citizens largely able to protect themselves from such warming. So 2 degrees might be manageable by the most economically developed nations (though, to be clear, it would not be without real costs); but it would be devastating to low-lying Pacific Island nations and coastal regions, as well as some of the hottest areas, like the Middle East, North Africa, and parts of Asia and South America. As climate activists recalibrated their goals and began to bring more visibility to the risks of allowing 2 degrees of warming, the Paris Accords-which 196 nations adopted in December 2015-pledged to keep warming under 2 degrees while acknowledging that it would be better to keep warming under 1.5 degrees. If we want to make that new, more ambitious target, we must limit carbon not to 450ppm but 430ppm, which drastically cuts the time we have in which to respond.

How close to that limit are we now? In 2022, the Mauna Loa Observatory in Hawaii recorded a CO2 concentration above 420ppm for the first time, and it's going up-fast. Over the last decade, the annual increase of CO2 concentration has been more than 2ppm, which means that we're on pace to hit 430ppm CO2 around the end of the decade, locking in 1.5 degrees Celsius warming.

So why all the optimistic talk by politicians, at climate summits, and on the news? Does a treaty like the Paris Accords indicate that we still have a chance at avoiding dangerous global warming?

Here's where the answer is technically yes, but not in a way that will make you feel any better.

The Intergovernmental Panel on Climate Change, or the IPCC, is the international body of the world's leading scientists which, every several years, puts out a new assessment report detailing the state of climate science, predictions about the future, and policy proposals that could change those predictions. In short, they tell us how bad things are and what we can do about it.

Over the course of 2021 and 2022, the IPCC put out its Sixth Assessment Report, which continued the trend of the previous five reports getting more alarming with each edition. The science is getting more mature, our predictions are getting more accurate, and the picture presented by that science and those predictions is getting scarier.