Different gases

[Bussy R]

Hi all.

 

Being a NOT scientist or whatever, (too hard for me) is the following correct? Just wondering.

 

Why CO₂ Might Not Be the Ultimate Villain We Were Told It Was

 

Regards Bussy

 

 

[Ken Kato]

The reason why too much CO2 is particularly bad is because of the sheer amount of it that regularly gets emitted into the atmosphere by humans compared to the other greenhouse gases (even though some of the others are more potent, they're not as abundant in comparison). 

Water vapour often gets quoted as one of those other potent gases in debates like these but as the article points out, it acts as a positive feedback mechanism where more warming from CO2 and other greenhouse gases = more evaporation from the ocean and vegetation = more water vapour = more warming, and so on.

Excessive CO2 also has a very long residence time in the atmosphere  i.e. it hangs around for hundreds to thousands of years which also makes it particularly bad.

In saying all that, it's important not to ignore those other gases either such as methane. Hence the umbrella term, greenhouse gases, for all them that enhance warming, 

Ken.

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From: aust...@googlegroups.com on behalf of Bussy R
Sent: Sunday, March 23, 2025 6:31 PM
To: Aussie weather
Subject: [austpacwx] Different gases

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[Gavin O'Brien]

Hi Bussy,
I agree with Ken CO2 is the largest emission by volume while the other green house gases are a much smaller amount. All are important and need to be taken into account when addressing global warming.
Gavin

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[Blair Trewin]

UNOFFICIAL

How long the gases stay in the atmosphere is also relevant - methane stays in the atmosphere for a shorter time than CO2 (one consequence of this is that reducing methane emissions has benefits more quickly than reducing CO2 emissions). 

As an IPCC author I'm obviously going to point to IPCC, and specifically figure 2 (which wasn't one of my bits) from the Summary for Policymakers (https://www.ipcc.ch/report/ar6/wg1/figures/summary-for-policymakers/figure-spm-2). This shows that the best estimate is that CO2 was responsible for about 0.8C of warming since 1850-1900, methane about 0.5C and nitrous oxide and other greenhouse gases 0.1-0.2 apiece. Offsetting this, about 0.5C of cooling is attributed to sulphur dioxide (or to put it in other terms, we've had about 0.5C less warming than we would have got from greenhouse gases alone).

Blair

UNOFFICIAL

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From: aust...@googlegroups.com <aust...@googlegroups.com> on behalf of Gavin O'Brien <southsi...@gmail.com>
Sent: Sunday, March 23, 2025 7:55 PM
To: aust...@googlegroups.com <aust...@googlegroups.com>
Subject: Re: [austpacwx] Different gases

 

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