3 ms·

And yet we DO have the historical record. I am no climate-change-denier (far from it), but the current concentration of CO2 is far from the historical maximum.

by sulam 10y ago

And yet we DO have the historical record. I am no climate-change-denier (far from it), but the current concentration of CO2 is far from the historical maximum. We can say with some confidence that the new equilibrium point is not likely to be Venus. Reaching it _is_ going to cause mass extinctions and _will_ have very negative effects for humanity, but the planet has been through this before and is probably going to be okay in timeframes measurably longer than our existence as a species. In geologic time frames, we are likely to be entering a domain where glaciation entirely disappears, including in Antarctica. The world was last here ~34M years ago, and sea levels were 200ft (60m) higher. I'm sure anyone reading this understands that this will have huge impacts on our day to day, including the drowning of most of the today's population centers. (If anyone is curious, research the Eocene, the era that likely has the best predictive power for what will be happening to our climate over the next few thousand years). Just imagine it running in reverse, at a greatly accelerated rate. And if you're wondering how we might avoid this fate, from an engineering perspective we need to recreate something like this: https://en.wikipedia.org/wiki/Azolla_event https://en.wikipedia.org/wiki/Azolla_event

mac01021 10y ago
I don't disagree with anything you just said, but many people take "history" to be distinct from "prehistory" (the latter ends and the former begins at the point in time when humans began to keep records of their affairs). So I caution you not to assume people are necessarily being disingenuous when they say something is at a historical high or whatever.
jfoutz 10y ago
So, i agree, not Venus. Not even as difficult as living under water. But the air would be hostile by default. So special equipment and housing would probably be required for long term survival. We'll all be settlers living on an earth-like planet. co2 material safety data sheet says 5000 ppm is max allowable for an 8 hour work day. [1] co2 levels (appear to) have a direct impact on cognition [2], specifically strategy and information usage. Ecoene had levels around 2000ppm. It'll be interesting to see if we overshoot or undershoot. Sensitive people start noticing effects at around 1k, perhaps as high as 2k for insensitive people. 2-5k "Headaches, sleepiness and stagnant, stale, stuffy air. Poor concentration, loss of attention, increased heart rate and slight nausea may also be present." [3] I don't think there have been any studies of long term exposure to 2k+ ppm (with no recovery time). as far as i know, nobody has to deal with that level of exposure for months or years. It's likely not good. But, as you say, not Venus. [1] https://www.airgas.com/msds/001013.pdf https://www.airgas.com/msds/001013.pdf [2] http://ehp.niehs.nih.gov/15-10037/ http://ehp.niehs.nih.gov/15-10037/ [3] https://www.kane.co.uk/knowledge-centre/what-are-safe-levels-of-co-and-co2-in-rooms https://www.kane.co.uk/knowledge-centre/what-are-safe-levels... (not a great source, but plausible)
- jcoffland 10y ago
  Maybe it's already been written but I would like to read a sci-fi novel where humanity realizes that our atmosphere is at risk and begins a race to capture it. The end result being that the planet's atmosphere is completely sucked up in to massive containers of liquid air. These are controlled by a few entities around the world, i.e. those who were most successful at liquefying air when it was free. Liquid air then becomes the main commodity about which all commerce is based. Who you get your air from determines your social status and vulnerability.
- flukus 10y ago
  Keep in mind that solar output itself has steadily increased since the eocene.
deleted 10y ago
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duncan_bayne 10y ago
> I am no climate-change-denier (far from it) Have we really reached the point where it's necessary to claim political correctness before embarking upon a discussion? Do you think it's necessary in order to have your opinion taken seriously, or to avoid moral opprobrium?

by sulam 10y ago

mac01021 10y ago

I don't disagree with anything you just said, but many people take "history" to be distinct from "prehistory" (the latter ends and the former begins at the point in time when humans began to keep records of their affairs). So I caution you not to assume people are necessarily being disingenuous when they say something is at a historical high or whatever.

jfoutz 10y ago

So, i agree, not Venus. Not even as difficult as living under water. But the air would be hostile by default. So special equipment and housing would probably be required for long term survival. We'll all be settlers living on an earth-like planet. co2 material safety data sheet says 5000 ppm is max allowable for an 8 hour work day. [1] co2 levels (appear to) have a direct impact on cognition [2], specifically strategy and information usage. Ecoene had levels around 2000ppm. It'll be interesting to see if we overshoot or undershoot. Sensitive people start noticing effects at around 1k, perhaps as high as 2k for insensitive people. 2-5k "Headaches, sleepiness and stagnant, stale, stuffy air. Poor concentration, loss of attention, increased heart rate and slight nausea may also be present." [3] I don't think there have been any studies of long term exposure to 2k+ ppm (with no recovery time). as far as i know, nobody has to deal with that level of exposure for months or years. It's likely not good. But, as you say, not Venus. [1] https://www.airgas.com/msds/001013.pdf https://www.airgas.com/msds/001013.pdf [2] http://ehp.niehs.nih.gov/15-10037/ http://ehp.niehs.nih.gov/15-10037/ [3] https://www.kane.co.uk/knowledge-centre/what-are-safe-levels-of-co-and-co2-in-rooms https://www.kane.co.uk/knowledge-centre/what-are-safe-levels... (not a great source, but plausible)

jcoffland 10y ago
Maybe it's already been written but I would like to read a sci-fi novel where humanity realizes that our atmosphere is at risk and begins a race to capture it. The end result being that the planet's atmosphere is completely sucked up in to massive containers of liquid air. These are controlled by a few entities around the world, i.e. those who were most successful at liquefying air when it was free. Liquid air then becomes the main commodity about which all commerce is based. Who you get your air from determines your social status and vulnerability.
flukus 10y ago
Keep in mind that solar output itself has steadily increased since the eocene.

deleted 10y ago

[deleted]

duncan_bayne 10y ago

> I am no climate-change-denier (far from it) Have we really reached the point where it's necessary to claim political correctness before embarking upon a discussion? Do you think it's necessary in order to have your opinion taken seriously, or to avoid moral opprobrium?