[Bored chemist]

I don't have any historic data below about ...

... anthropogenic CO2

[alancalverd]

I think there is some obscure law of chemistry that says CO2 is CO2, regardless of its source.

[alancalverd]

Is that because it magically measures the concentration and changes the rules of physics when it exceeds 200?

It is precisely because the laws of physics don't change, that increasing the concentration becomes less significant at high concentrations. And as I said, I don't have any historic data much below 200 ppm.

All we know is that the concentration of CO2 in the atmosphere has historically followed the temperature graph, not led it. We have no reason to believe that the laws of physics have changed since the Big Bang. So the obvious but currently unpopular conclusion is that CO2 is not the driver of temperature under recent and current atmospheric conditions..

[Bored chemist]

I think there is some obscure law of chemistry that says CO2 is CO2, regardless of its source.

There's another "obscure" thing you are ignoring, rate of change of CO2 concentration IS dependent on source.
So there's nothing in the historical record which can tell you about what happens when the CO2 concentration rises as fast as it is doing at the moment.
That's because man made CO2 IS different.
It is sudden.

[Bored chemist]

So the obvious but currently unpopular conclusion is that CO2 is not the driver of temperature under recent and current atmospheric conditions..

The scientific conclusion is that it WAS not the driver, but that was before we turned up.
There is no scientific conclusion based on past records for an unprecedented rate of change.
So we have to look at the underlying physics.
More CO2 will produce more warming.
There's nothing "magic" about 200 ppm.

[alancalverd]

The CO2 concentration has risen very quickly in the past, and always after the temperature rise.

What's "magic" about 200 ppm is that the value hasn't been much lower than that at any time in the past 500,000 years. The temperature has always risen rapidly when the "anomaly" reached -8 K (and CO2 was about 190 ppm) as was the case about 20,000 years ago. We are now apparently approaching the cusp of the cycle, with an "anomaly" of 2 - 3 K.

I put "anomaly" in quotes because the  reference point seems to be 1940. This is a significant date in climate science because it represents the point at which it was important (and possible) to collect huge quantities of high quality daily meteorological data  from pretty well everywhere on the planet. But the global average temperature for the last 500,000 years is actually 4K below the reference, which rather underplays the 12K range of the historic cycle: the true anomaly at present is about 6K, not the 1 or 2 K that NOAA publishes. 

rate of change of CO2 concentration IS dependent on source

[ Agreed. So what caused the change from 190 to 290 ppm in the 20,000 years before we started using fossil fuels? Or the even more spectacular rise 100,000 years before that?

Here's an interesting quote from a fairly middle-of-the road commentator: 

One result of this is, for example, that the famous iceman ‘Ötzi’, who disappeared under ice 5000 years ago, reappeared in 1991.

Does that make sense? How on earth did he "disappear under ice?" He wasn't found in a lake, but up a mountain. The evidence is that the hollow in which he died was later covered by a glacier which recently retreated. So it got a lot colder at some time between 3,300 BC and the present, not quite the impression you get from the quote....

[Bored chemist]

The CO2 concentration has risen very quickly in the past,

Not really.
It is currently rising about 100 times faster.

Why do you not hear this when I tell you?

[alancalverd]

It is currently rising about 100 times faster.

...than when it rose slower. Not that the rate of increase is important because surely any effect would depend on the amount present, not the rate at which it is increasing.

[Bored chemist]

than when it rose slower.

No, nitwit,  a hundred times faster than ever before.

. Not that the rate of increase is important

Except when it suits you...

If you don't think it's important, why did you raise the issue?

The CO2 concentration has risen very quickly in the past

[Petrochemicals]

Co2 is increaced to 400ppm, double 200ppm that is touted. Does not is seem strange that the global warming effect is so minimal?

[alancalverd]

If you don't think it's important, why did you raise the issue?
Quote from: alancalverd on Yesterday at 16:39:51
The CO2 concentration has risen very quickly in the past

Because rapid rises of CO2 concentration in the past have not caused rapid temperature rises, which would make a scientist  wonder why they should do so now.

[Origin]

Co2 is increaced to 400ppm, double 200ppm that is touted. Does not is seem strange that the global warming effect is so minimal?

It only seems strange to someone who is ignorant of the science surrounding global warming.

[Bored chemist]

Co2 is increaced to 400ppm, double 200ppm that is touted. Does not is seem strange that the global warming effect is so minimal?

No

[Bored chemist]

which would make a scientist  wonder why they should do so now.

Not if that scientist realised that CO2 absorbs IR.

[Petrochemicals]

Co2 is increaced to 400ppm, double 200ppm that is touted. Does not is seem strange that the global warming effect is so minimal?

It only seems strange to someone who is ignorant of the science surrounding global warming.

OK Mr poopy pants

[alancalverd]

Co2 is increaced to 400ppm, double 200ppm that is touted. Does not is seem strange that the global warming effect is so minimal?

It only seems strange to someone who is ignorant of the science surrounding global warming.

When I see a model that explains all the historic data, rather than merely extrapolating forwards from a recent correlation, I will recognise someone who is not ignorant of the science of climate change, or at least has some respect for science. 

[Colin2B]

Co2 is increaced to 400ppm, double 200ppm that is touted. Does not is seem strange that the global warming effect is so minimal?

It only seems strange to someone who is ignorant of the science surrounding global warming.

OK Mr poopy pants

There have been warnings about this behaviour. Let's keep it friendlier.

[Bored chemist]

When I see a model that explains all the historic data,

OK
There are "slow" drivers of climate change. Things like Milankovitch cycles.
From time to time, they drive the temperature of the earth past the tipping points and we get increased concentrations of CO2, methane and water vapour in the air.
Because those are positive feedback mechanisms, they produce quite rapid increases in temperature and the concentrations of those GH gases.
The temperatures rise for a while until those same slow drivers overcome the effects of the GH gases.

I already explained this to you, and provided an analogy (the neon oscillator) in a field you are familiar with,
https://www.thenakedscientists.com/forum/index.php?topic=83465.msg659192;topicseen#msg659192


Now imagine that, at a time when the slow drivers say nothing interesting should be happening, we add a lot of CO2 to the air, very rapidly and we trigger the same positive feedback mechanisms.
What will happen?

[alancalverd]

Slow drivers do not explain the historic data unless the tipping point is a -8K anomaly, which seems unlikely (most modern "models" have a tipping point at + 2 or +3K).

If they did, then the "interesting" period began 20,000 years ago, as it appears to have done, and there is nothing anomalous about the status quo.

My concern is that if what you have said is true and consistent with history, then reducing anthropogenic CO2 is not going to avert a humanitarian disaster.

[Bored chemist]

My concern is that if what you have said is true and consistent with history, then reducing anthropogenic CO2 is not going to avert a humanitarian disaster.

My concern is that if what I said is true, and we don't cut CO2 emissions then we will certainly provoke a humanitarian disaster.

On the other hand,
https://en.wikipedia.org/wiki/What_if_it%27s_a_big_hoax_and_we_create_a_better_world_for_nothing%3F