My take on 'Don't Look Up'

Asteroids and warming ...

The other day, I watched - for a second time - the movie satire ‘Don’t Look Up’. It’s about the inability of scientists to get action to do anything about an asteroid of diameter 10 km that’s on a collision path with planet Earth. They’re thwarted at every turn by the infotainment industry masquerading as the news.

It was released in 2021. My favourite character was Meryl Streep doing a great job of playing the self-serving President of the USA, along with her idiot son who was Chief of Staff (any guesses who they might represent?). I also loved Cate Blanchett’s renditions of what looked suspiciously like Fox TV’s ‘news’ host Laura Ingram. Never were truer words said in jest…. For the time. And times haven’t improved.

The whole thing was a metaphor for our inaction on Climate Change. It’s even more poignant today with the passage into law of tRump’s Big Ugly Bill. July 4 2025 will go down as a dark day for the world’s future. He’s single-handedly trying to ensure that insanity on fossil fuels prevails. And he’s happy for his disciples to pay a premium for their energy in doing so. I wonder if they’ll be as happy when they realise they’ve picked up the tab for the increased subsidies he’ll be giving to the fossil fuel tycoons. Somebody should tell him (again) that renewables are already a much cheaper alternative. They’re also the only viable long term solution.

But, I digress. And the film is a lot more fun. Spoiler alert. The asteroid duly arrived, and mankind was wiped out (sorry about that).

I’m sure you readers still enjoy the movie, though Rotten Tomatoes gave it a only lukewarm reception. The first time I watched it I didn’t get as far as the hilarious end-piece that followed the credits, set 22,000 years into the future. It’s a must-see 😊.

Asteroid impacts are inevitable. You need only to look at the moon to see that. Without vegetation and the ravages of weathering, multiple craters from past impacts are clear for all to see - frozen in time.

The density of asteroid cratering will be similar on planet Earth, but not as obvious because three quarters of them are beneath the oceans, and the remainder are mostly hidden by tectonic shifts, weathering and vegetation. But a few spectacular examples remain, the largest being the Vredefort crater in South Africa from an impact 2 billion years ago which left a crater of diameter 300 km.

The most recent impact of comparable size to that in the movie was 66 million years ago in the Yukutan Peninsula of Mexico. Called the Chicxulub impact, it left a crater of diameter of 150 km and caused tidal waves reputedly kilometres high. I mention it here because the dust-cloud from it’s debris is thought to have blocked sunlight long enough to extinguish plant life on Earth. And that, famously, led to the extinction of the dinosaurs.

There could have been multiple extinction events before that, because by then Planet Earth was already nearly 5 billion years old (as it still is). The time since the extinction of the dinosaurs therefore represents only 1 percent of Earth’s history. Something resembling mankind arrived on the scene less than half a million years ago, so ‘our’ time on the planet represents less than 0.01 percent of Earth’s history. A blink of the eye in those terms.

Over Earth’s history, there have been dramatic swings in temperature (and in life, or lack-of-life). It was much warmer at the time of the dinosuars, and remained slightly warmer when the first humans evolved. But at no time in the last 100 thousand years have global temperatures exceeded current values. The current rate of increase is already unprecedented in history, and over the coming decades it’s expected to increase even faster, at the rate of nearly 0.3 degrees Celsius per decade. It’s only in the last century or so that population densities have been sufficient to challenge Earth’s ecological capacity. So, it’s nonsense to dismiss the threats of climate change with comments like ‘the temperature has always gone up and down’. Now, with 8 billion people on the planet to be fed, even small changes are problematic.

Because of associated increases in sea-level with Climate Change, the preponderance of population centres near the coast is a huge and inexorable economic and social burden. But future asteroid impacts would pose an immediate existential risk. If a 10 km diameter asteroid were to again impact, we could again expect tsunamis with heights of a kilometre or more. With unheeded warnings - as in the film - that threats instant obliteration of most of the world’s coastal population centres. Some, like the tiny minority living at higher altitudes, would survive that initial surge. But not for much longer. The dust cloud from debris thrown into the atmosphere could again lead to mass extinctions, with or without warnings being heeded. At least skin cancer from UV exposure wouldn’t be a problem (for a point of relevance to you subscribers to UV & You 😊).

The other good news is that statistics are firmly on our side. Google tells me that for asteroids of diameter 1 km the probability of impacting planet Earth is only once every half-million years. And for these extinction-event behemoths - of diameter greater than 10 km – impacts are expected to occur only once every 100 million years. That means that over the lifetime of the planet, there will have been about 50 such events.

Based on the law of averages, it looks like we may still have 30 million years up our sleeves until the next one! I’ll take my chances on that! 😊 😊 I read in the intro to Bill Bryson’s ‘A Short History of Nearly Everything’ that, on average, lifeforms on planet Earth last only 4 million years before going into extinction. Based on the evidence so far, I doubt if our span will be much more than average.

I’m pretty confident I’ll personally survive climate change. Something else is bound to get me first. But I’m not so confident about future generations. Compared with asteroid-strikes, it’s akin to the tortoise in Aesop’s The Tortoise and the Hare.