Temperatures above 50C used to be a rarity confined to two or three global hotspots, but the World Meteorological Organization noted that at least 10 countries have reported this level of searing heat in the past year: the US, Mexico, Morocco, Algeria, Saudi Arabia, Kuwait, Iran, Pakistan, India and China.
In Iran, the heat index – a measure that also includes humidity – has come perilously close to 60C, far above the level considered safe for humans.
Heatwaves are now commonplace elsewhere, killing the most vulnerable, worsening inequality and threatening the wellbeing of future generations. Unicef calculates a quarter of the world’s children are already exposed to frequent heatwaves, and this will rise to almost 100% by mid-century.
Like Life on earth has survived more extreme environments before. Not only microbes but multicellular life should be fine.
Source for this prediction? What are you basing this on?
Great question, I glad you asked. When I said both multicellular and microbial life would be fine, what I meant is it’s unlikely either would be wiped totally out.
As highlighted in the article you linked, only about 90% of [multicellular] species died out during the Permian-Triassic Extinction Event, specifically the “things have been worse before” situation I was thinking about. Also noted in the article is that the conditions we’re experiencing now are not to the same degree although we’re observing events similar to what we understand may have happened during the Permian-Triassic Extinction, again to a much lesser degree.
Keep in mind atmospheric CO2 levels were estimated to be around 2500 ppm, about 6 times greater than our current levels of around 420 ppm. Preindustrial CO2 levels were 270 ppm, so we’ve added about 150 ppm. It’s not all that much but it’s enough to start changing things for the worse for many of the planet’s current inhabitants.
As to microbial life, I’m a microbiologist so I know my microbes. They as a whole are far more resilient and will outlast all multicellular life. Some thrive in conditions where no multicellular life on Earth could survive. Even if conditions were so hostile than no microbes could survive, some form endospores. These are incredibly resilient little escape pods that can remain viable for millions of years, then reactivate when conditions are better, reconstituting back to bacteria.
While extinctions are frankly depressing, they do open ecological niches into which other species with suitable traits can expand and, given time and selective pressure, differentiate. For example, all we’d need is mice and a suitable food source to survive and, a few million years later, the earth will be covered with various species decended from both of them.
When you said life would be fine, what you meant was it may MOSTLY all die and may take millions of years to evolve again. That’s not “fine.”
Second, we really don’t know that it will ever evolve again or that other conditions won’t deteriorate. Bacteria can’t live in molten lava. Biology has a general upper and lower limit before things start denaturizing. Our moon is further away and the earth isn’t as young as it once was. The conditions that gave rise to life so long ago might not be replicable enough in the future.
I agree that it’s likely extremophiles at least will survive. I don’t take for granted that it definitely will happen and I don’t call it “fine.”
