RonO wrote:
https://www.washington.edu/news/2024/04/17/ice-age-climate-analysis-reduces-worst-case-warming-expected-from-rising-co2/
https://www.science.org/doi/10.1126/sciadv.adk9461
These climate scientists looked at the carbon dioxide level and
temperature shifts during the last ice age, and they are claiming that
CO2 levels may not produce the temperatures that others are claiming.
For technical reasons the estimated warming from a given CO2 increase
has a very long tail on the positive side. It's even more skewed than
the Maxwell-Boltzmann distribution (images available by search).
As a result, when this kind of statistics was first done around the turn
of the century, it was impossible to rule out an increase of 10.5
degrees for a doubling with 95% confidence.
Since nobody actually believes that a ten degree warming for a doubling
is possible, work began on more complex statistics, generally Baysian,
to see if the result held up. I was a co-author on one of those in
which we found the 95% limit to be about six degrees. Since that time
it has fallen further.
The original naive estimate of 1.5-4.5 from the late 70s still seems to
be reasonable. For that matter the estimates of Svante Arrhenius from
the 1890s seem to be good.
The last warm interval got warmer than the current interval, but CO2
wasn't the issue. Under current conditions they think that
temperatures will not get to the levels that have been predicted, so
more ice may not melt than last time
Someone should start working on the possiblity that we may delay the
next cold period. That might melt as much ice as last time, and be
much worse for arctic biology. There was a group that was predicting
that CO2 could delay and even cause a skipping of the next cold
period That might be the biggest worry at this time.
So you didn't read my previous reply?
William Hyde
RonO wrote:
https://www.washington.edu/news/2024/04/17/ice-age-climate-analysis-reduces-worst-case-warming-expected-from-rising-co2/
https://www.science.org/doi/10.1126/sciadv.adk9461
These climate scientists looked at the carbon dioxide level and
temperature shifts during the last ice age, and they are claiming that
CO2 levels may not produce the temperatures that others are claiming.
For technical reasons the estimated warming from a given CO2 increase
has a very long tail on the positive side. It's even more skewed than
the Maxwell-Boltzmann distribution (images available by search).
As a result, when this kind of statistics was first done around the turn
of the century, it was impossible to rule out an increase of 10.5
degrees for a doubling with 95% confidence.
Since nobody actually believes that a ten degree warming for a doubling
is possible, work began on more complex statistics, generally Baysian,
to see if the result held up. I was a co-author on one of those in
which we found the 95% limit to be about six degrees. Since that time
it has fallen further.
The original naive estimate of 1.5-4.5 from the late 70s still seems to
be reasonable. For that matter the estimates of Svante Arrhenius from
the 1890s seem to be good.
The last warm interval got warmer than the current interval, but CO2
wasn't the issue. Under current conditions they think that
temperatures will not get to the levels that have been predicted, so
more ice may not melt than last time
Someone should start working on the possiblity that we may delay the
next cold period. That might melt as much ice as last time, and be
much worse for arctic biology. There was a group that was predicting
that CO2 could delay and even cause a skipping of the next cold
period That might be the biggest worry at this time.
So you didn't read my previous reply?
William Hyde
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