What I've been reading, featuring climate change only: “The Uninhabitable Earth” by David Wallace-Wells, the moral imperative of alarmism, and climate intersectionality

“The Uninhabitable Earth: Life After Warming” by David Wallace-Wells

  • I’m not sure the title claim is advanced in the book or supported by the climate literature so some people may justifiably feel deceived (and maybe also by the cover; when the mass bee deaths feature, its connection to climate is dismissed). As far as I understand, certain parts of the world—small island nations and some vulnerable coastal cities—are on track to be submerged pending political intervention and others in South Asia and the Middle East will regularly have weather exceeding the limits of human survivability. But that’s just 30% of the world’s population for 20 days a year currently and maybe 48-74% of the population by 2100 depending on what we do. By then, that study estimates, many equatorial locations like Jakarta, Indonesia are expected to experience deadly heat 365 days a year. Luckily, the city will probably be completely below sea level anyway. So literally the entire Earth uninhabitable? Nah. Just conducive to heat death on a daily basis for hundreds of millions of powerless people thousands of miles away and the land inhabited by 5% of the world’s population will experience chronic submergence. And then the next century will start.

    To be less flippant, the title serves mostly to make explicit the book’s origin as the author’s 2017 long-form (here’s a version annotated by scientists), which quickly became New York magazine’s most read article ever (though it’s since been unseated by a “Fire and Fury” excerpt). Many called the original article’s focus on and presentation of worst-case scenarios sensationalist, maybe most prominent among them the climatologist and climate science communicator Prof. Michael Mann. In Mann’s words, his problem with the article was “the fact that there were SCIENTIFIC INACCURACIES that PREFERENTIALLY fed a somewhat doomist narrative.” In contrast, with this book adaptation, “David has done his due diligence, vetted the science, and gotten it right.” Since the publication of the original article, Mann and Wallace-Wells have participated in a public conversation hosted by NYU to discuss the communication of climate science and have jointly promoted the book.

  • To me, the book is overwhelmingly a success and potentially an important leap forward in advancing how the public understands the enormity of the climate change problem. By ‘public’, I also mean to include academics from other disciplines and the op-ed intelligentsia who’ve decided to stake a claim of expertise in the area now that the Green New Deal proposal has made the topic politically relevant.

  • Part of this contribution may be its updating the language of climate change. “97% consensus” and the questions of its happening and of human attribution are old. Here’s some new:

  • The main criticism I’ve seen levied against the book and similar ones has been that they are alarmist. While sometimes an appropriate epithet used to throw cold water on inappropriately extreme messaging (see the cloud study mentioned at the bottom of this post), it’s also had the effect of dismissing necessary attempts to bring the public up to speed with our current understanding of the consequences of climate change, which has advanced significantly in recent years. Wallace-Wells’ work embraces the adjective: his recent NYT opinion piece adapted from the book uses the headline “Time to Panic.” The book’s first sentence, the same as the original article’s, is “It is worse, much worse, than you think.” And on page 138: “If you have made it this far, you are a brave reader.”

    This gets to the heart of an outstanding issue with public engagement on the impacts of climate change. Any honest reading of the growing interdisciplinary literature on climate impacts should induce panic, a natural expression of empathy for the most vulnerable human beings on our planet. From my perspective, to admonish those who feel fear amounts to promotion of injustice and ignorance. Two climate journalists discuss that here.

    Noah Smith recently had what I think is a lazy take on the dangers of climate panic when comparing being upset by the prospects of climate impacts to the fear to itself be feared during the Great Depression:


To hone in on the Great Depression analogy, there is no meaningful parallel between the mass panic of bank runs collapsing the international economy to the supposed chaos that would ensue from learning what climate change does. When has high public concern ever led to commensurate or over-compensating policy? As pointed out here, the metaphorical mapping would not have the concerned public playing the FDR role; it would be more like everyone but FDR noticing the stock market crashing and then pressuring the bumbling President to take action at an appropriately revolutionary scale. If made in good faith, it’s a silly if not harmful argument for Noah to half-ass for an important topic.

It also seems to be the opposite criticism to the typical one made about alarmism, which is that it induces political defeatism and paralysis. I realize I’m focusing on a single tweet, but Smith has over 135,000 Twitter followers and a Bloomberg column so his thinking out loud in 280 characters at a time to try to reconcile his staunch neoliberalism with the catastrophic embodiment of its shortcomings is unfortunately influential. A bit more on this later below.

We’ve lived with climate indifference for the past few decades and it hasn’t produced any meaningful policy. In contrast, the urgency of the young Democratic progressives made climate change maybe the defining issue of the 2020 Democratic primary before they were even sworn into Congress, this after none of the US presidential or vice-presidential debates from the last two races included a single question about climate change. To drive home the opportunities climate indifference has squandered, consider this hypothetical that Wallace-Wells presents:

“If we had started global decarbonization in 2000, when Al Gore narrowly lost election to the American presidency, we would have had to cut emissions by only about 3 percent per year to stay safely under two degrees of warming. If we start today, when global emissions are still growing, the necessary rate is 10 percent. If we delay another decade, it will require us to cut emissions by 30 percent each year.”

The idea of fear inhibiting meaningful action is disputed in social movement theory (h/t @cityatlas) and I hope I am not out of line in invoking the spirit of civil rights movements:

“I want you to understand how overwhelming, how insurmountable it must have felt [in the Jim Crow South]. I want you to understand that there was no end in sight. It felt futile for them too. Then, as now, there were calls to slow down. To settle for incremental remedies for an untenable situation. They, too, trembled for every baby born into that world.

“You don’t fight something like that because you think you will win. You fight it because you have to. Because surrendering dooms so much more than yourself, but everything that comes after you. Acquiescence, in this case, is what James Baldwin called ‘the sickness unto death.’

“…What, now, do you have to lose? What else can you be but brave?”

In 2017, 150 Indians carried the skulls of their fellow farmers—some small subset of the 320,000 driven to suicide due to uncharacteristic climate-driven crop damage between 1995 and 2016—and trekked to the capital Delhi to protest naked and sitting down for almost a month to demand a policy response: “We wanted to symbolically shame our leaders into action.” So the notion that the relatively wealthy and climate-insulated can’t be trusted to inform themselves about climate change because they might accidentally do too much out of fear is offensive, in my opinion. Maybe anti-alarmism is also part of the new climate denialism.

Figure 4:  “Country-level shares of the global social cost of carbon (GSCC) versus shares of the 2013 CO2 emissions. The CSCC is the median estimate with growth adjusted discounting (ρ = 2%, μ = 1.5) for SSP2/RCP6.0 and BHM-SR. Points are shaded by CSCC per capita and sized according to country GDP in 2015. Diagonal lines show the ratio of the GSCC share to the emissions share. Ratios greater than 1:1 indicate that a country’s share of the GSCC exceeds its share of global emission. The box in the left panel indicates the bounds of the detail shown in the right panel.”   From: “ Country-level social cost of carbon ” , Nature Climate Change   8 , 895–900 (2018)

Figure 4: “Country-level shares of the global social cost of carbon (GSCC) versus shares of the 2013 CO2 emissions. The CSCC is the median estimate with growth adjusted discounting (ρ = 2%, μ = 1.5) for SSP2/RCP6.0 and BHM-SR. Points are shaded by CSCC per capita and sized according to country GDP in 2015. Diagonal lines show the ratio of the GSCC share to the emissions share. Ratios greater than 1:1 indicate that a country’s share of the GSCC exceeds its share of global emission. The box in the left panel indicates the bounds of the detail shown in the right panel.”

From: “Country-level social cost of carbon, Nature Climate Change 8, 895–900 (2018)

  • It is this notion of injustice that I think resonated most while reading this book and even while contributing the little I have to climate research. Wallace-Wells make the point that we’ve now expelled more greenhouse gases while aware of its contribution to the global greenhouse effect than we ever did in ignorance going back to the dawn of the industrial revolution. There is an intuitive unfairness now in “trying to bring many hundreds of millions more into the global middle class while knowing that the easy paths taken by the nations that industrialized in the nineteenth and even twentieth centuries are now paths to climate chaos.” I highlighted Presidents Barack Obama and Narendra Modi acknowledging that unfairness here in a section about the Paris Agreement from Ben Rhodes’ White House memoir last year.

    The legacy of other oppressive institutions such as colonialism, slavery, and Western exceptionalism permeate the narrative of climate change. The first figure at right shows that Saudi Arabia, India, Brazil, and Indonesia are expected to bear the largest share of economic growth impacts relative to their contribution of carbon emissions. For India and Brazil, this ratio is estimated to be roughly 4:1 (but maybe President Bolsonaro’s deforestation can swing the ratio towards equity). The two biggest emitters—the United States and China—are net beneficiaries by this definition, China by a less than 1:4 ratio.

    There is a normalized disregard for the well-being of those in vulnerable areas already suffering tremendously from climate change even among those prepared to embrace the science of climate. How else to interpet the Nobel committee approving the Nordhaus recommendation that 3.5 degrees of warming is optimal the same day that the devastating IPCC Report on 1.5 warming came out? How else to read these suggestions (tweets embedded to the right) that the brutal reality of climate change has finally arrived only now that it’s violently affected the United States in the last two years?

    The only dimension along which climate change has been "far off" was in geography and political power. In 2013, even before Haiyan, 85% of Filipinos reported personal experience with climate change impacts, 54% of them describing them as “severe”. In 2015, 54% of Hispanic Americans rated global warming as “extremely or very important to them personally”. In 2017, monsoon-exacerbated floods affected 45 million in South Asia and submerged two thirds of Bangladesh, including parts of the makeshift hillside camps where nearly a million Rohingya refugees have been forced to settle at risk of death by disease or mudslides. When will developing countries or the vulnerable within developed countries get their say as frequently as do white op-ed writers or public intellectuals who command enormous platforms on seemingly any issue of their choosing regardless of experience or expertise? They haven’t yet. Anti-alarmism and Western exceptionalism would have you discount the value of those lives.

  • Other than harrowing research findings, I think a problem in climate communications is its failure to capture the imagination. A small chapter in the book poses a question I’ve wondered myself: Where is the great climate-change novel? Land war, nuclear winter, artificial intelligence, and other generation-defining threats have inspired influential works of art, but none springs immediately to mind about climate change.

    “Mad Max: Fury Road”, while an action masterpiece, is only tenuously climate-related considering its desert dystopia was conceived before 1979. “Interstellar” was all right. I had been hoping from the trailer and its first half that “First Reformed” could be that movie, but I think it’s third act may have veered off message and it didn’t garner the Academy’s attention (not even an acting nomination for an outstanding entry by Ethan Hawke). Maybe “Woman At War” can be one.

    Music-wise, I can only think of ANOHNI’s “4 Degrees” which was released in the context of the Paris Agreement. Thom Yorke, the vegetarian frontman of carbon-neutral Radiohead has said, “If I was going to write a protest song about climate change in 2015, it would be shit.”

    Wallace-Wells offers some plausible explanations for its unique storytelling challenges, but I worry the answer may also be related to the aforementioned inequality.

  • Next on the climate reading list: “Storming the Wall: Climate Change, Migration, and Homeland Security” by Todd Miller


Climate stuff elsewhere

  • Young people for climate justice

  • Linked to above, but reposting here for emphasis: federal disaster money favors the rich

An NPR investigation has found that across the country, white Americans and those with more wealth often receive more federal dollars after a disaster than do minorities and those with less wealth. Federal aid isn't necessarily allocated to those who need it most; it's allocated according to cost-benefit calculations meant to minimize taxpayer risk.

Put another way, after a disaster, rich people get richer and poor people get poorer. And federal disaster spending appears to exacerbate that wealth inequality.

"The demonization of carbon dioxide is just like the demonization of the poor Jews under Hitler. Carbon dioxide is actually a benefit to the world, and so were the Jews."

What I've been reading, featuring carbon dividends, Robert Caro's research process, and a breakthrough in non-line-of-sight imaging

  • Guillermo Del Toro reflects on “Roma”, his countryman and friend’s masterpiece now nominated for Best Picture:

Finally, he raised his head. “I didn’t know someone from Princeton could do digging like this,” he said. “From now on, you do investigative work.”

I responded with my usual savoir faire: “But I don’t know anything about investigative reporting.”

Alan looked at me for what I remember as a very long time. “Just remember,” he said. “Turn every page. Never assume anything. Turn every goddam page.” He turned to some other papers on his desk, and after a while I got up and left.

Caro is famous for the obsessive research underlying his biographies of Robert Moses and Lyndon B. Johnson. The latter has been a four-volume project (publications in 1982, 1990, 2002, and 2012) with a fifth and concluding volume characteristically overdue. His next book, “Working”, is a memoir and is due out in a few months:

Why am I publishing these random recollections toward a memoir while I’m still working on the last volume of the Johnson biography, when I haven’t finished it, while I’m still—at the age of eighty-three—several years from finishing it? Why don’t I just include this material in the longer, full-length memoir I’m hoping to write?

The answer is, I’m afraid, quite obvious.. I am well aware that I may never get to write the memoir, although I have so many thoughts about writing, so many anecdotes about research, that I would like to preserve for anyone interested enough to read them. I decided that, just in case, I’d put some of them down on paper now.

I also recommend listening to his appearance last year on the New Yorker Radio Hour (embedded below), which he at the end calls the best interview he’s ever had. Read also this interview with the New York Review. I have not read any of his books.

  • This is California, the creepy progressive dreamland of contradictions dominated by the real-estate lobby

“I have interviewed a number of the characters Mark Lilla cites in his essay' ‘Two Roads for the New French Right’. Lilla’s account fails to confront the white supremacy at the heart of a movement he ultimately describes as a ‘coherent worldview'.’ Although he is correct that there are important evolutions underway on the French and European right, he overlooks an implacable bigotry that remains the essence of the project. Any responsible discussion of the movement’s new developments must begin and end there.”

And Lilla replies:

“Writing about the political right has never been harder. Different kinds of right-wing ideologies and political formations are proliferating and shaking liberal governments around the world… This makes it difficult to keep track of all the developments, distinguish them, and establish the connections between them. At the same time, liberal and left forces that want to resist these developments are increasingly hostile to learning anything that does not conform to their settled ideas about the right.

“…a reader of McAurley’s letter who had not seen the piece might come to a different conclusion: that it was intended to whitewash Marion [Maréchal ] (or her grandfather, or right-wing forces everywhere; it’s unclear which) and ignore the real animating forces on the right, which are ‘white supremacy,’ ‘hatred of the other,’ ‘bigotry,’ and ‘an ideology of exclusion,’ all whipped up by the phantom of immigration. In other words, never mind all the things that seem new, forget the writings about family and sexuality, forget all the talk about organic community, forget the lashing out against neoliberalism and tech giants, forget Pope Francis. It all comes down to hatred: ‘Any responsible discussion of the movement’s new developments must begin and end there.’”

  • Questions that have been weighing on my mind ever since I’ve thought about working in development:

Figure 1: “Controlled by a laptop PC, the standard digital camera obtains a snapshot of the irradiance distribution on a visible imaging wall, which is induced by the penumbra of an occluding object owing to light emanating from a scene of interest. The scene of interest is displayed on an LCD monitor for ease of performing experiments with many scenes. The snapshot is fed through a computer algorithm to recover an image of the scene of interest and an estimate of the position of the hidden occluder.”  From: “  Computational periscopy with an ordinary digital camera   ”, Nature   565 , 435-436 (2019)

Figure 1: “Controlled by a laptop PC, the standard digital camera obtains a snapshot of the irradiance distribution on a visible imaging wall, which is induced by the penumbra of an occluding object owing to light emanating from a scene of interest. The scene of interest is displayed on an LCD monitor for ease of performing experiments with many scenes. The snapshot is fed through a computer algorithm to recover an image of the scene of interest and an estimate of the position of the hidden occluder.”

From: “Computational periscopy with an ordinary digital camera”, Nature 565, 435-436 (2019)

What I've been reading, featuring my vote in the 2016 election and the mediocrity of “Vice”

“By now it should be obvious that Facebook’s so-called pro-democracy rhetoric has been fundamentally damaging to real democracies and to democratic movements around the world. It has also directly benefited authoritarian regimes, which have relied on the platform to spread untruths in order to control and manipulate their citizens. In the Philippines, as content moderators busily remove posts and pictures according to a bespoke metric developed by “mostly twenty-something-year-olds” in Menlo Park, California, the president, Rodrigo Duterte, is busy on Facebook too, using paid followers to spread falsehoods about his critics and his policies. The journalist Maria Ressa, whose news organization, Rappler, has been keeping a database of the more than twelve million Facebook accounts that have attacked critics of Duterte and have been traced back to the president, has been a target of those accounts as well, at one point getting as manmy as ninety hate messages an hour via Facebook—messages like ‘I want Maria Ressa to be raped repeatedly to death.’

“…in countries like the Philippines and Myanmar, where the vast majority of people access the Internet through Facebook, not using the platform is likely not an option. Indeed, establishing an equivalence between Facebook and the Internet is one of the payoffs of Free Basics, an app Facebook created that provides purposefully limited Internet access—there is no stand-alone e-mail server and Facebook is the only social media platform—to people in developing countries who wouldn’t otherwise be able to afford to go online.”

There was a special futility in my mailing my overseas ballot against Duterte in 2016 when I lived three minutes from Facebook’s East Palo Alto–gentrifying campus. Like even though I could well have been the only voter in the Philippine elections living in this historically disenfranchised American city still suffering from its legacy of redlining, racial segregation, crime, violence, and public neglect, the net contribution of my small neighborhood to my home country 7000 miles away was nothing less than the corrosion of its democracy.

“Hatred might not come into it for Finnis, but there is little doubt that hating, disliking, maligning gay people – and creating the conditions under which gay people come to loathe themselves – follow from his proposals…

“When I read my straight colleagues telling everyone else to give Finnis the ‘respect’ of engaging with his opinions, to ‘make arguments’ in response, I wonder how many times they have had to ‘make the argument’ for their happiness, for their home and their partner, for the life they’ve built with the people they love. At times, I’m not even sure what I am meant to be making the argument for. It does not matter if my gayness was innate or chosen, it is so deeply a part of me, such a root cause of any fulfilment that I feel and any good that I do, that it becomes clear that what really follows from Finnis’s view is that I should stop existing as me. I should retreat into some other Sophie, who lives without the woman who makes her a better teacher, listener, thinker. Finnis thinks my good would be actualised in an unhappy marriage with a man. But almost everything I know about the virtues, I learned from my experiences as a gay woman: courage, constancy, generosity, love. I can engage, certainly, I can make arguments in response, but there is also a sense, at a deeper level, in which there is nothing I can say.”

  • I didn’t really like “Vice” (2018), the Adam McKay film about Dick Cheney

    • As with McKay’s previous film “The Big Short”, which I enjoyed, the movie is defined by its narration, dark comedy, and hyper-stylized editing. I’m all for that and bought in the instant the trailer was released. It just wasn’t done nearly as well in the final product. Definitely some highlights, but if you take on Cheney and the neoconservative world order on this large a platform, you have a responsibility to do so thoughtfully. That’s not a criticism of the stylization or comedic take of the film; I just mean that if you’re going to take on this subject and license the recency, pain, and footage of real events, you should submit a product that demonstrates more effort went into its formulation. Everything about this felt unfinished .

    • For one thing, the 2-hour, 12-minute movie didn’t decide whether it was going to be a biopic or an exploration of the cruelty of the Bush-Cheney Iraq War. The first half runs through Cheney’s life, but he’s already a diabolical opportunist from the outset: early scenes include him unbothered by a colleague’s shattered leg and only choosing to identify as a Republican for its career advantages. This isn’t a character study then. Similarly, if the second half of the movie is about the cruelty of the Bush-Cheney administration during the Iraq War, why did we spend the entire first half on a mostly-irrelevant overview of Cheney’s career path? The movie’s “Where Are They Now?” epilogue suggests McKay’s movie is ‘about’ the cost of the unnecessary Iraq War; if that’s the takeaway of the movie, then humanizing Cheney and spending time on anything more than the broad strokes of his non-political life story shouldn’t occupy nearly as much time as it did.

    • Also it used its ending monologue to accuse the audience of complicity in Cheney’s empowerment. That would be OK if there were any lead-up to it, but the movie showed he was unelectable whenever he ran at the front of a ticket and entered the private sector because of it. Cheney’s power came from unprecedented diminution of a president behind the scenes and away from public scrutiny. How then is Cheney’s foreign policy the public’s fault? Just felt completely out of left field for that to be presented as the message of the movie.

    • The narration is awful. It’s somehow indignantly sanctimonious and condescending while also not explaining enough what was wrong. It spent a lot of time re-emphasizing the same point about the Unitary Executive Theory—not that hard a concept from what I can tell—while glossing over the exact details of how it was exploited. We had a very cool montage of Cheney installing his men in different sections of government, but we never actually see how he used the machine he built to create the war he wanted other than when they mention he had a lot of offices. Yes, we see that Halliburton influenced his Iraq policy—very subtle: on election night, Cheney reads his wife a text saying they got “double what we expected” as their exit bonus—but other than a map of oil wells and a spreadsheet of energy companies, we don’t know what the administration actually did for them in Iraq. At one point, Rumsfeld asks Cheney whether they’d be indicted and the audience doesn’t even really know what the hypothetical charges would be.

    • Sam Rockwell in the wake of last year’s Oscar win turns in a bad SNL impression as George W. Bush. Similarly lazy: at some point McKay asked himself how to convey Steve Carrell’s Donald Rumsfeld’s evil and decided the answer was to have someone ask him what his values are and have him laugh and shut the door on them. Come on now, how are you going to spend all that runtime on Cheney’s pre-political years but not spend time on Rumsfeld’s brand of evil?

    • “Vice” as in ‘vice president’ and “Vice” as in ‘bad’ because the vice president was bad

    • Rare instance where the Reddit comments are generally on point

    • All in all, my frustration stems from seeing an argument I sympathize with being made poorly and without focus or sense of story-telling, which I feel is almost more devastating to an argument than a good counterargument.

    • If you wanted a ridiculously over-the-top challenge to the moral corruption of the crony capitalist elite, the WWE did it better:


“When people of color enter elite spaces, they make those with unearned advantages conscious of how they’ve been favored by the system. That poses a choice to those whose access to such cloistered communities is unquestioned: They can recognize that others might also succeed given the right circumstances, or they can defend the inequities of that system in an effort to preserve their self-image, attacking the new entrant as a charlatan or the group they belong to as backwards.”

  • Spotify’s revenue-sharing model is dumb

  • Book club selection #3: “Pnin” (h/t Lucy) by Vladimir Nabokov (whose last name I learned to mispronounce from Sting). The theme of blissful ignorance made this tweet a somewhat apt unintentional summary:

  • Have aliens found us? The interview is a mess but even more enjoyable when you imagine Dr. Avi Loeb as the scientist in a B movie whose calculations correctly predict an incoming alien invasion but everyone ignores him because his hair is messy and whenever he tries to explain his theory, he keeps dropping papers of printed-out spreadsheets and then a high-ranking bureaucrat who’s in cahoots with the aliens sneeringly tells him that they’re cutting his funding and confiscating his desktop computer.

  • Conan O’Brien contemplating his legacy as his late-night show restructures into a 30-minute format (h/t Junho)

“Calvin Coolidge was a pretty popular president. I’ve been to his grave in Vermont. It has the presidential seal on it. Nobody was there. And by the way, I’m the only late-night host that has been to Calvin Coolidge’s grave. I think that’s what separates me from the other hosts.

“I had a great conversation with Albert Brooks once. When I met him for the first time, I was kind of stammering. I said, you make movies, they live on forever. I just do these late-night shows, they get lost, they’re never seen again and who cares? And he looked at me and he said, [Albert Brooks voice] “What are you talking about? None of it matters.” None of it matters? “No, that’s the secret. In 1940, people said Clark Gable is the face of the 20th Century. Who [expletive] thinks about Clark Gable? It doesn’t matter. You’ll be forgotten. I’ll be forgotten. We’ll all be forgotten.” It’s so funny because you’d think that would depress me. I was walking on air after that.”

Relevant: his recent appearance on the Comedy Bang Bang podcast. The style of the podcast is often absurdist, fast pace, and highly improvisational. Associating Conan with the late-night monologuing format that I’ve long found trite, I was really impressed by his ability not just to keep up with host Scott Aukerman, but to outwit him with ease. It’s a strange duality that I frequently confront with Conan, Late Show-era Stephen Colbert, and the best SNL alumni: their undeniable innate talent and intelligence contrasted against the mediocrity of their TV shows.

  • Two-time Oscar-nominated director Jonah Hill and Tony-nominated Broadway star Michael Cera in conversation for the A24 podcast. Apparently they co-starred in a movie together when they were teenagers.


What I've been reading, featuring the Cretaceous-Paleogene extinction event and the infuriating etymology of narwhals

  • Was intrigued by this excerpt on the basis for the asteroid theory of dinosaur extinction. I was interested since like everyone, I was aware it was the prevailing explanation but had always been taught to beware it was unsettled science and never learned the basis for its favored status. Too interesting that the theory’s originator also contributed to the Manhattan Project and the design of the nuclear bomb dropped on Nagasaki.

With the help of his father, Alvarez had samples of the clay analysed for iridium, a heavy metal that is rarely found on Earth’s surface, but which is common in space, and which falls from the heavens as cosmic dust at a fairly constant rate. The Alvarezes were trying to ascertain how quickly or slowly the band had been deposited. If one assumes the typical pace of accumulation, a large amount of iridium would suggest it had taken a long time, indicating that the extinction process may also have been lengthy; a small amount would suggest that a quick event had overtaken the Earth. But the samples contained a surprise: huge amounts of iridium, so much that it would have taken tens or hundreds of millions of years to deposit at background rates. What could explain it? The Alvarezes came to a radical conclusion: the high concentration of iridium in the band must have come from outer space, and it must have been delivered in bulk by a colossal asteroid strike – an event destructive enough to have triggered the end-Cretaceous extinction. The iridium-rich clay band at Gubbio was the shroud of dust and debris that had eventually settled on a devastated world.

As the same iridium anomaly began to be detected at sites around the world, the Alvarezes’ notion of an asteroid strike followed by the blotting out of the sun was substantiated. It also had an influence beyond palaeontology; when Brusatte describes the aftermath of the impact as being like a nuclear winter, he is gently reverse-engineering the concept, for the idea of a nuclear winter – the darkening and cooling of the world by the dust thrown into the atmosphere after a nuclear exchange – was explored and popularised in the 1980s partly with reference to the Alvarez hypothesis. Meanwhile, the iridium testing and the hypothesis itself came of the Alvarezes’ connections to nuclear science. Luis Alvarez had been a key player in the Manhattan Project, and had helped design ‘Fat Man’, the bomb that was dropped on Nagasaki.

The title of the article derives from the author contemplating the modern-day relevance of the end-Cretaceous event eliminating all dinosaurs but not other animals: “When there is sudden global environmental and climate change, what lives and what dies?” And before you reject the assumption there, it acknowledges "the realisation that birds are dinosaurs is probably the single most important fact ever discovered by dinosaur palaeontologists.”

Also, the article begins with a graphic description of the extinction event, but I find it pales in comparison to this one from a different book:


Still, there are a small minority of holdouts in the debate, such as Prof. Gerta Keller of Princeton, who is a proponent of the Deccan Traps explanation, which attributes dinosaur extinction mostly to a series of volcanic eruptions in West India. The Atlantic had a lengthy article last year on the academic debate surrounding the end-Cretaceous event titled “The Nastiest Feud in Science” featuring some ad hominem attacks and cross-disciplinary antagonism with dissenters fearing for their careers, which makes the natural and social sciences seem not so different after all. It’s more a fascinating portrait of academic hostility on an apolitical topic than an educational one that reliably weighs the balance of evidence, I think. I myself am partial to this theory: