A photograph of multiple explosions going off together, emitting red and orange sparks and lots of blue-grey smoke.

Christopher Nolan’s explosion

In May, Total Film reported that the production team of Tenet, led by director Christopher Nolan, found that using a second-hand Boeing 747 was better than recreating a scene involving an exploding plane with miniatures and CGI. I’m not clear how exactly it was better; Total Film only wrote:

“I planned to do it using miniatures and set-piece builds and a combination of visual effects and all the rest,” Nolan tells TF. However, while scouting for locations in Victorville, California, the team discovered a massive array of old planes. “We started to run the numbers… It became apparent that it would actually be more efficient to buy a real plane of the real size, and perform this sequence for real in camera, rather than build miniatures or go the CG route.”

I’m assuming that by ‘numbers’ Nolan means the finances. That is, buying and crashing a life-size airplane was more financially efficient than recreating the scene with other means. This is quite the disappointing prospect, as must be obvious, because this calculation limits itself to a narrow set of concerns, or just one as in this case – more bang for the buck – and consigns everything else to being negative externalities. Foremost on my mind is carbon emissions from transporting the vehicle, the explosion and the debris. If these costs were factored in, for example in terms of however much the carbon credits would be worth in the region where Nolan et al filmed the explosion, would the numbers have still been just as efficient? (I’m assuming, reasonably I think, that Nolan et al aren’t using carbon-capture technologies.)

However, CGI itself may not be so calorifically virtuous. I’m too lazy in this moment to cast about on the internet for estimates of how much of the American film industry’s emissions CGI accounts for. But I did find this tidbit from 2018 on Columbia University’s Earth Institute blog:

For example, movies with a budget of $50 million dollars—including such flicks as Zoolander 2, Robin Hood: Prince of Thieves, and Ted—typically produce the equivalent of around 4,000 metric tons of CO2. That’s roughly the weight of a giant sequoia tree.

A ‘green production guide’ linked there leads to a page offering an emissions calculator that doesn’t seem to account for CGI specifically; only broadly “electricity, natural gas & fuel oil, vehicle & equipment fuel use, commercial flights, charter flights, hotels & housing”. In any case, I had a close call with bitcoin-mining many years ago that alerted me to how energy-intensive seemingly straightforward computational processes could get, followed by a reminder when I worked at The Hindu – where the two computers used to render videos were located in a small room fit with its own AC, fixed at 18º C, and when they were rendering videos without any special effects, the CPUs’ fans would scream.

Today, digital artists create most CGI and special effects using graphics processing units (GPUs) – a notable exception was the black hole in Nolan’s 2014 film Interstellar, created using CPUs – and Nvidia and AMD are two of the more ‘leading’ brands from what I know (I don’t know much). One set of tests whose results a site called ‘Tom’s Hardware’ reported in May this year found an Nvidia GeForce RTX 2080 Ti FE GPU is among the bottom 10% of performers in terms of wattage for a given task – in this case 268.7 W to render fur – among the 42 options the author tested. An AMD Radeon RX 5700 XT GPU consumed nearly 80% as much for the same task, falling in the seventh decile. A bunch of users on this forum say a film like Transformers will need Nvidia Quadro and AMD Firepro GPUs; the former consumed 143 W in one fur-rendering test. (Comparability may be affected by differences in the hardware setup.) Then there’s the cooling cost.

Again, I don’t know if Nolan considered any of these issues – but I doubt that he did – when he ‘ran the numbers’ to determine what would be better: blowing up a real plane or a make-believe one. Intuition does suggest the former would be a lot more exergonic (although here, again, we’re forced to reckon with the environmental and social cost of obtaining specific metals, typically from middle-income nations, required to manufacture advanced electronics).

Cinema is a very important part of 21st century popular culture and popular culture is a very important part of how we as social, political people (as opposed to biological humans) locate ourselves in the world we’ve constructed – including being good citizens, conscientious protestors, sensitive neighbours. So constraining cinema’s remit or even imposing limits on filmmakers for the climate’s sake are ridiculous courses of action. This said, when there are options (and so many films have taught us there are always options), we have a responsibility to pick the more beneficial one while assuming the fewest externalities.

The last bit is important: the planet is a single unit and all of its objects occupants are wildly interconnected. So ‘negative externalities’ as such are more often than not trade practices crafted to simplify administrative and/or bureaucratic demands. In the broader ‘One Health’ sense, they vanish.