" Net Isotopic Signature of Atmospheric CO2 Sources and Sinks: No Change since the Little Ice Age
by Demetris Koutsoyiannis [ORCID]

Recent studies have provided evidence, based on analyses of instrumental measurements of the last seven decades, for a unidirectional, potentially causal link between temperature as the cause and carbon dioxide concentration ([CO2]) as the effect. In the most recent study, this finding was supported by analysing the carbon cycle and showing that the natural [CO2] changes due to temperature rise are far larger (by a factor > 3) than human emissions, while the latter are no larger than 4% of the total. Here, we provide additional support for these findings by examining the signatures of the stable carbon isotopes, 12 and 13. Examining isotopic data in four important observation sites, we show that the standard metric δ13C is consistent with an input isotopic signature that is stable over the entire period of observations (>40 years), i.e., not affected by increases in human CO2 emissions. In addition, proxy data covering the period after 1500 AD also show stable behaviour. These findings confirm the major role of the biosphere in the carbon cycle and a non-discernible signature of humans."

https://www.mdpi.com/2413-4155/6/1/17

He uses isotopic data from Scripps Institute. ;)

Also Lee,
we're actually in a sort of ice age -
if we weren't Antarctica would be melted and the sea levels would be 100s of meters higher.
Antarctic has an average height of 2.5km above sea level  - mostly a thick layer of ice.

Poor JM. Just can't help himself. If it is  not Milankovitch cycles it must be human. ;D ;D ;D ;D ;D

lee wrote on Apr 10^th, 2024 at 1:34pm:

" Net Isotopic Signature of Atmospheric CO2 Sources and Sinks: No Change since the Little Ice Age by Demetris Koutsoyiannis [ORCID] Recent studies have provided evidence, based on analyses of instrumental measurements of the last seven decades, for a unidirectional, potentially causal link between temperature as the cause and carbon dioxide concentration ([CO2]) as the effect. In the most recent study, this finding was supported by analysing the carbon cycle and showing that the natural [CO2] changes due to temperature rise are far larger (by a factor > 3) than human emissions, while the latter are no larger than 4% of the total. Here, we provide additional support for these findings by examining the signatures of the stable carbon isotopes, 12 and 13. Examining isotopic data in four important observation sites, we show that the standard metric δ13C is consistent with an input isotopic signature that is stable over the entire period of observations (>40 years), i.e., not affected by increases in human CO2 emissions. In addition, proxy data covering the period after 1500 AD also show stable behaviour. These findings confirm the major role of the biosphere in the carbon cycle and a non-discernible signature of humans." He uses isotopic data from Scripps Institute. ;)

This certainly sets the cat amongst the climate science pigeons.

I guess what's open here is what the hell is causing the temperature to rise?

I would have loved to post this quote from Carl Sagan here:

rclutz.files.wordpress.com/2023/09/carl-sagan-science-as-free-inquiry.png

Polyphemus wrote on Apr 10^th, 2024 at 5:00pm:

I guess what's open here is what the hell is causing the temperature to rise?

Well, as JM freely admits there has been global brightening due to various Clean Air Acts. That means there are less particulates, less pollution, so the Sun is not reduced by those particulates. Therefore, we have global warming. So it could be said that the Clean Air Acts, have indeed promoted AGW. ;)

And yet there is a possible increase in metal elements (particles) in the ionosphere due to the thousands (and increasing) of re-entering space junk and satellites burning up.
This may cause problems to the magneto-sphere and ozone hole?
If this is the growing case, then a Carrington Effect would fry a lot of the electronic civilisation - if a direct hit.