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"CO2 levels higher": Would you mind sharing your source on this? Here are the last 6,000 years [1] (it cuts off at 4713 BC because that happens to be the earli

by brchr 10y ago

"CO2 levels higher": Would you mind sharing your source on this? Here are the last 6,000 years [1] (it cuts off at 4713 BC because that happens to be the earliest timestamp available in Postgres). The source data from the NOAA are here [2] and you can see for yourself that we are something like 30% higher than the highest level of CO2 recorded in the last 800,000 years. If you have a source that tells a different story, let me know. [1] https://numer.al/noaa_data/figures/antarctic-ice-cores-revised-800kyr-co2-data https://numer.al/noaa_data/figures/antarctic-ice-cores-revis... [2] ftp://ftp.ncdc.noaa.gov/pub/data/paleo/icecore/antarctica/antarctica2015co2composite.txt

adrianN 10y ago
During the Devonian and Carboniferous time (~400 million years ago) Earth was like 20 degrees warmer and CO2 was really high.
- deleted 10y ago
  [deleted]
- Diederich 10y ago
  That's correct. If memory serves, it's been >400 ppm quite a few times since. The earth, and rich (though temporarily diminished) life on its surface will continue. I suspect there will be a much smaller number of humans to enjoy it.
- brchr 10y ago
  Okay, so we can say that: 1. CO2 is currently the highest it has ever been since human civilization has existed (10k years, roughly). 2. CO2 is currently the highest it has ever been since humans have existed (200k years, roughly). 3. CO2 is currently the highest it has ever been since primates have existed (50M years, roughly). But for the sake of argument let’s say: 4. CO2 may not be the highest it has ever been since mammals have existed (200M years, roughly). 5. CO2 is not the highest it has ever been since multicellular life has existed on land (500M years, roughly). Fair enough. Maybe 1-3 are less concerning to you than they are to me. When you say "the climate has been warmer in the past and CO2 levels higher" and are referring to a period prior to the existence of primates, it doesn't necessarily make me feel that much better. :) That said I’m nothing close to being expert in this stuff. It’s interestingly difficult to think about time over so many orders of magnitude.
  - WorldMaker 10y ago
    I like this xkcd's comic cosmic perspective: http://xkcd.com/1732/ http://xkcd.com/1732/
  - notyourwork 10y ago
    When put in this perspective it is hard to not be concerned about 1-3.
phkahler 10y ago
You just need to go back in time further than the ice age: https://en.wikipedia.org/wiki/Ice_age https://en.wikipedia.org/wiki/Ice_age "Outside these ages, the Earth seems to have been ice-free even in high latitudes." If you want to maintain the status quo and not allow human impact on the climate, you can expect the glaciers to arrive sooner rather than later: https://en.wikipedia.org/wiki/Ice_age#/media/File:Vostok_Petit_data.svg https://en.wikipedia.org/wiki/Ice_age#/media/File:Vostok_Pet...

by brchr 10y ago

adrianN 10y ago

During the Devonian and Carboniferous time (~400 million years ago) Earth was like 20 degrees warmer and CO2 was really high.

deleted 10y ago
[deleted]
Diederich 10y ago
That's correct. If memory serves, it's been >400 ppm quite a few times since. The earth, and rich (though temporarily diminished) life on its surface will continue. I suspect there will be a much smaller number of humans to enjoy it.
brchr 10y ago
Okay, so we can say that: 1. CO2 is currently the highest it has ever been since human civilization has existed (10k years, roughly). 2. CO2 is currently the highest it has ever been since humans have existed (200k years, roughly). 3. CO2 is currently the highest it has ever been since primates have existed (50M years, roughly). But for the sake of argument let’s say: 4. CO2 may not be the highest it has ever been since mammals have existed (200M years, roughly). 5. CO2 is not the highest it has ever been since multicellular life has existed on land (500M years, roughly). Fair enough. Maybe 1-3 are less concerning to you than they are to me. When you say "the climate has been warmer in the past and CO2 levels higher" and are referring to a period prior to the existence of primates, it doesn't necessarily make me feel that much better. :) That said I’m nothing close to being expert in this stuff. It’s interestingly difficult to think about time over so many orders of magnitude.
- WorldMaker 10y ago
  I like this xkcd's comic cosmic perspective: http://xkcd.com/1732/ http://xkcd.com/1732/
- notyourwork 10y ago
  When put in this perspective it is hard to not be concerned about 1-3.

phkahler 10y ago

You just need to go back in time further than the ice age: https://en.wikipedia.org/wiki/Ice_age https://en.wikipedia.org/wiki/Ice_age "Outside these ages, the Earth seems to have been ice-free even in high latitudes." If you want to maintain the status quo and not allow human impact on the climate, you can expect the glaciers to arrive sooner rather than later: https://en.wikipedia.org/wiki/Ice_age#/media/File:Vostok_Petit_data.svg https://en.wikipedia.org/wiki/Ice_age#/media/File:Vostok_Pet...