Comment by photochemsyn | Hacker News Reader

Comment by photochemsyn | Hacker News Reader

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I think 'existential' is a bit overused with respect to fossil fueled global warming. Full-scale nuclear war, or a major asteroid impact, would be existential. The rise in temperature and associated issues like extreme weather (droughts/floods/storms), sea level rise, the loss of permanent glaciers are serious issues but the timeline is slow enough (10 years per noticeable change) that adaptation is quite possible, to some extent.

Indeed adapatation is absolutely required, as we've tipped the system such that even if we halt fossil fuel use overnight, or (more plausible) over the next 50 years, permafrost melt, shallow ocean sediment warming, etc. will continue to leak ancient carbon into the atmosphere. We're heading back to climate conditions last seen in the Pliocene (3-5 million years ago), like it or not.

As far as mining, yes, it can be made cleaner but that just costs at least twice as much (because you have to spend as much on processing the waste and cleaning up the water as you do on developing the mine). The answer to that is tighter regulations, so that a dirty miner can't undersell a clean miner.

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.

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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