Atmospheric CO2 absorption - actual quantification?

[bhobba]

As I tell people that ask - its a complex issue The chemical society's write-up is just a start. What I hate is something I saw on a program discussing this. There was a climate scientist on the panel. He was asked about the opinions of a political commentator. They are wrong, even I saw they were wrong, but superficially they look good. What was his answer - I am a climate scientist and I am telling you they are wrong. That is not science - he could have easily explained why they are wrong - but didn't. As people into science we have an obligation to explain what we do know and what we do not.

Thanks
Bill

 

[scvblwxq]

As an aside, we are in a long-term ice age that started around 2.6 million years ago. An informal geologic definition of an ice ace is a period of time when ice exists year round in nature, such as Greenland. We are between glacial periods within the long-term ice age in a warm interglacial period. In the last interglacial it seems like it was warmer than it is projected to get even with current CO2 production. https://en.wikipedia.org/wiki/Ice_age We are in the coldest part of the Earth's history for the past 500 million years. https://en.wikipedia.org/wiki/Geologic_temperature_record

 

[cmb]

As the atmosphere (the global system, not some parcel or air) being in equilibrium (between the amount of water evaporating and condensing, not being at 100% humidity).

I am at risk of a thread deviation of my own thread, but ... errrr, so just for clarity what do you think causes rain?

If the air is always at some constant equilibrium % humidity and doesn't reach 100% occasionally, do you think rain is created by some other process than the dew point being reached? Like, rain dancing or something?

 

[Bandersnatch]

With all due respect, I think you're being intentionally obtuse.

 

[cmb]

Just say what you think this equilibrium level is, then?

 

[bhobba]

Just say what you think this equilibrium level is, then

The general principle is rather easy. Water vapor from the sun heating oceans, lakes etc - rises - the higher you go the colder it gets and it begins to condense, form droplets and falls to earth. This forms an equilibrium along with other gasses. Now let's add a little bit of another greenhouse gas like CO2 - but there are many others eg O2 and Methane. They have a crucial difference to water - they do not condense out. This little bit raises temperature a little bit which causes more evaporation, more water vapor, and hence by the greenhouse effect the temperature rises, so you get a positive feedback loop. This is the runaway greenhouse effect some worry about. But to counter this more clouds form which absorbs some of the sunlight reaching Earth so less water vapor and you have the opposite effect - a lowering in temperature. It will form a new equilibrium. To try and figure the equilibrium out we have climate models - and of course there are obviously other factors involved - they too must be taken into account.

The above is just the basics, but I think anyone into science should know it and be able to explain it to people. There are people that think the small amount of CO2 added by man can't possibly make any difference - and they can mount a very persuasive argument - the above explains why that is wrong.

But the models do not all produce the same result eg MIT researchers has the runaway effect not happening until we reach 152%:
http://news.mit.edu/2018/how-earth-sheds-heat-space-0924
Slightly worrying though is it does not contain a link to the associated peer reviewed paper.

Others say doom is only about 11 years away.

This is the sort of thing that makes discussing climate science - how to put it - problematical. I am fairly sure of the basics - but beyond that - shrug.

Thanks
Bill

 

[cmb]

The general principle is rather easy. Water vapor from the sun heating oceans, lakes etc - rises - the higher you go the colder it gets and it begins to condense, form droplets and falls to earth. This forms an equilibrium along with other gasses. Now let's add a little bit of another greenhouse gas like CO2 - but there are many others eg O2 and Methane. They have a crucial difference to water - they do not condense out. This little bit raises temperature a little bit which causes more evaporation, more water vapor, and hence by the greenhouse effect the temperature rises, so you get a positive feedback loop. This is the runaway greenhouse effect some worry about. But to counter this more clouds form which absorbs some of the sunlight reaching Earth so less water vapor and you have the opposite effect - a lowering in temperature. It will form a new equilibrium. To try and figure the equilibrium out we have climate models - and of course there are obviously other factors involved - they too must be taken into account.

The above is just the basics, but I think anyone into science should know it and be able to explain it to people. There are people that think the small amount of CO2 added by man can't possibly make any difference - and they can mount a very persuasive argument - the above explains why that is wrong.

But the models do not all produce the same result eg MIT researchers has the runaway effect not happening until we reach 152%:
http://news.mit.edu/2018/how-earth-sheds-heat-space-0924
Slightly worrying though is it does not contain a link to the associated peer reviewed paper.

Others say doom is only about 11 years away.

This is the sort of thing that makes discussing climate science - how to put it - problematical. I am fairly sure of the basics - but beyond that - shrug.

Thanks
Bill

I didn't spot the number there. Did I miss it?

 

[bhobba]

I didn't spot the number there. Did I miss it?

No. Unless you want to actually get the measurements, and I have no idea where they are, you can search for them as easily as I can - if they exist - then you must consult the models. My point is they give wildly different answers.

We know the general mechanism but specifics seem in short supply. If others know the exact numbers please post them. But I have to ask what good would they be? We do not know the tipping point or even which of the two effects I mentioned will win out.

Thanks
Bill