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Comment by exoverito | Hacker News Reader

CO2 levels were triple current levels at 1500 ppm about 50 million years ago. This was during the Cenozoic era when mammals first rose to dominance. Clearly the Earth was livable then.

https://attheu.utah.edu/science-technology/geoscientists-map...

Modern temperatures are actually near an all time low for the past 485 million years.

https://www.climate.gov/media/16817

Consider the possibility that you are mistaken, and the victim of propaganda.

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Did you check the sea levels back then? It is estimated to be 100m higher than now. And you know around half of the earths population live on land that would be sea in that case? So yes the earth can survive higher CO2 levels and higher sea levels, especially if the changes are gradual (over millions of years).

But the chances you will personally be adverse affected by anthropogenic climate change in your lifetime is pretty damn high. Humanity will survive, but many humans will die in horrible conditions

Of course it goes without saying, the ecological niches and evolutionary adaptations different species earned through 50m years of CO2 lowering, they can obviously just do it again if we were to drastically change the CO2 numbers over like a hundred years instead.

We can tell that this is right and logical because the number of insects, a population more sensitive to environmental trends, hasn't visibly and obviously changed at all.

For the readers that might miss it: that the last sentence was sarcastic: https://www.reuters.com/graphics/GLOBAL-ENVIRONMENT/INSECT-A...

The earth also had a molten surface for millions of years before that. You’re right, earth doesn’t give a f*. But humans need a much more moderate environment to thrive.

For example, If you look at cognitive performance in humans, it scales directly up with oxygen levels and directly down with CO2. We talk about levels above 1500 ppm,, but if you look at the data, it scales in a nice straight line all the way back as far as you want to measure it. As temperatures rise, less and less areas are habitable. And temperatures are rising. So we get more crowded, and make progressively worse decisions.

Just like insects used to be able to be huge due to different atmospheric conditions, humans are able to be highly intelligent and thrive due to the unusual atmospheric and climatic conditions we have experienced in the recent period. We are bringing that period to a close.

But sure, life will thrive somewhere. Just not human life.

Yea, ok, I implied livable for humans obviously. And I meant including the current level of technology, not as cave men, as cave men don't care about the large scale GDP cost of nations.

I saw Joe Rogan share the same graph to support his claim that scientists don't know anything about the climate and that the ones who claim to all have conflicts of interest; I can't recall if it came before or after the ad-break for all-natural, grass-fed and methane-relieved Beef Stix.

If you zoom in on the tiny sliver at the end of that graph, the portion that represents the last million years or so, you'll see that we're rocketing upwards at an unprecedented rate. We're experiencing one of the fastest sustained rates of temperature change on geological scales, outpaced only by isolated incidents like dinosaur-killing meteors. But, even if that wasn't the case, geological scales aren't what matters! The question is: what rate of change can our civilization and current biosphere (whose organisms had millions of years to adapt to the current climate) tolerate? The mountain of evidence and research that you'd call "propaganda" suggests that humanity and the rest of life on earth is not well-equipped to tolerate changes this fast.

Consider the possibility that you are mistaken, and have your head in the sand.

Thank you! Totally agreed!

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