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Comment by SECProto | Hacker News Reader

I think you're underestimating the impact that climate change will have, most importantly from human migration, food shortages, and war (which are secondary impacts of climate change, as opposed to the primary impacts you've listed). But I also think you've underestimated the primary impacts: you're assuming that the rate of change is stable, and it's absolutely not.

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I'd note that the CO2 response, i.e. the amount of heat trapped as atmospheric CO2 rises, is neither exponential, nor linear, but rather logarithmic. That means the effect of going from 180->280 ppm - i.e. roughly an ice age minimum to maximum variation over the past two million years - is a probably greater than going from 280->420 ppm (the current industrial rise over the past ~200 years). So the rate of change is highly unlikely to suddenly spike.

https://climate.nasa.gov/vital-signs/carbon-dioxide/

Of course, we should be working overtime to eliminate fossil fuels from the energy mix, but these claims that something is going to blow up overnight are just not scientifically supported - basically, statistically discernable changes are taking place on the scale of about 8-10 years if you look at the records. Meaning, climate in 2000 was clearly cooler than climate in 2010, but 2005-2010 is just noise.

That doesn't account for any hysteresis in the system. The weather extremes we are experiencing now are not due to emissions last year, but to emissions multiple decades ago

Regardless, comparing pre-industrial average with an ice age minimum and then saying "we probably haven't gotten quite so much warmer again" is ...not a comforting reframing of the situation.

The responses of the climate system are pretty well understood at this time, and nothing approaches 'existential', i.e. extinction-level - which I'd reserve for major asteroid strikes, supervolcanoes, and total nuclear war. Equating fossil-fueled global warming to such events is simply scientific exaggeration. It's a notch down the logarithmic scale of doom from them, is all I'm saying.

What fossil-fueled global warming entails is more like a constant, steady grind with the grind getting noticeable worse over successive time periods (perhaps about a decade, maybe a little less). Conditions that span extreme weather are getting more frequent (mostly due to more water vapor in the atmosphere), record-breaking droughts in some regions are on the rise, 500-yr floods now take place every 5 years, etc.

Fundamentally, however, none of this is going away - it takes 100 years at least for global climate to equilibrate to current forcing, and again, there are some feedback effects dumping ancient stores of carbon slowly into the atmosphere.

Practically, this means as much energy and money are going to have to be spent on adapting to new conditions as on eliminating fossil fuels from the energy mix.

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