Too late? Why scientists say we should expect the worst

[chrisc]

At about 20 ppm CO2, effectively all IR radiation is captured.

So at, and above, 20ppm no IR radiation would reach the surface of the planet...?

I think he means the radiation from the planet surface, which has different wavelengths to the stuff coming in from the sun.

Ah, so I should have said, at and above, 20ppm no IR radiation would leave the atmosphere of the planet?

[RevdTess]

Apparently, it's not like having a black curtain over a window:

Nice

[RevdTess]

Ah, so I should have said, at and above, 20ppm no IR radiation would leave the atmosphere of the planet?

Apparently so! Not one iota. All stays here forever.

I'm sure he just meant that at 20ppm CO2 captures as much as it's ever going to do. But I guess I should let him speak for himself.

But I am interested to know now why the 50-year-old physics that Blue Peter refers to is considered bogus by MacG et al.

[Bandidoz]

it's the absorption in the thin upper atmosphere (which is unsaturated) that counts

So, questions for Tess's BF.....

1) Is there a known relationship between CO2 levels at ground and in the upper atmosphere?

2) It's implied that CO2 saturation at ground level doesn't stop IR escaping. At what height would such saturation be significant?

3) Is the transfer function logarithmic (i.e. suppose 10ppm lets through 50%, 100ppm lets through 2%, 1000ppm lets through 1%)?

[Cabrone]

Some of them do deny this and some go even further and argue that more CO2 is a good thing...

But they don't deny that adding more CO2 captures more ir radiation, and, all other things being equal, will therefore make the planet hotter?


Peter.

It's like having a black curtain over a window. Adding another black curtain wont make the room darker. At about 20 ppm CO2, effectively all IR radiation is captured. The thing follow a logarithmic called Beer's Law. Its impossible to capture more than 100% of the IR radiation.

Everything indicate that CO2 is merely a trailing indicator, not a leading cause.

This hyping of CO2 is just junk science. Some people get some kind of jolt from their reward systems when they think that they act altruistic. Thats all. Please go home and forget this hysteria.

It's not junk science atall.

Ångström's saturation argument was rebuffed in Real Climate a few years ago, here is the Link for you.

Here is the summary:

if a skeptical friend hits you with the "saturation argument" against global warming, here's all you need to say:
(a) You'd still get an increase in greenhouse warming even if the atmosphere were saturated, because it's the absorption in the thin upper atmosphere (which is unsaturated) that counts
(b) It's not even true that the atmosphere is actually saturated with respect to absorption by CO2,
(c) Water vapor doesn't overwhelm the effects of CO2 because there's little water vapor in the high, cold regions from which infrared escapes, and at the low pressures there water vapor absorption is like a leaky sieve, which would let a lot more radiation through were it not for CO2, and
(d) These issues were satisfactorily addressed by physicists 50 years ago, and the necessary physics is included in all climate models.

The guys at RC go on to write a 2nd article about What Ångström didn’t know.

Ångström was a good scientist but his measurements were made over 100 years ago. In 1900 his CO2 saturation argument was a powerful one because at the time scientists didn't understand how the stratified layers in the atmosphere interact.

Today they do and thus his 'saturated' argument can be explained and dealt with in climate models.

[RevdTess]

So, questions for Tess's BF.....

Unfortunately he just keeps saying, "They're all nutters" and refuses to get involved

Good questions though.

[chrisc]

Unfortunately he just keeps saying, "They're all nutters" and refuses to get involved

LOL, I don't blame him, it's true!

[Bandidoz]

<reposted>

[RevdTess]

The guys at RC go on to write a 2nd article about What Ångström didn’t know.

I just read through the article. Very interesting. It's a lot more complicated than I realised. I can follow the argument reasonably well but the science is way beyond me of course. It rather leaves little option but to accept on faith that they know what they're doing.

[clv101]

I have seen no evidence that CO2 has any bearing on global temperatures.
I've been told it as fact for close to two decades, but never seen the evidence, never mind proof, from which I conclude there isnt any.

This part of the science, at least, seems overwhelmingly conclusive.

I'm not a physicist so I can't prove it from first principles. However my bf, (who does have the physics PhD, and who worked on ice sheet melting rates) assures me that the evidence for CO2 influence on temperature is far stronger than mere empiricism but can be derived from the chemical nature of CO2 itself - ie proper science not just correlations of coincident observed datapoints.

Like I said, I'm in no position to judge but I'm hardly going to go against my bf's view in an area in which he's clearly the expert.

Precisely - a decent chemistry text book will detail an experiment DominicJ could perform to provide evidence. It was first published quantitively by Svante Arrhenius in 1896.

I'm sorry but comments like that from DominicJ just go to discredit anything he has no say on the matter.

[MacG]

So, questions for Tess's BF.....

Unfortunately he just keeps saying, "They're all nutters" and refuses to get involved

Good questions though.

Yea, that's my stance also. Sometimes I slip though.

[MacG]

But they don't deny that adding more CO2 captures more ir radiation, and, all other things being equal, will therefore make the planet hotter?


Peter.

It's like having a black curtain over a window. Adding another black curtain wont make the room darker. At about 20 ppm CO2, effectively all IR radiation is captured. The thing follow a logarithmic called Beer's Law. Its impossible to capture more than 100% of the IR radiation.

Everything indicate that CO2 is merely a trailing indicator, not a leading cause.

This hyping of CO2 is just junk science. Some people get some kind of jolt from their reward systems when they think that they act altruistic. Thats all. Please go home and forget this hysteria.

It's not junk science atall.

Ångström's saturation argument was rebuffed in Real Climate a few years ago, here is the Link for you.

Here is the summary:

if a skeptical friend hits you with the "saturation argument" against global warming, here's all you need to say:
(a) You'd still get an increase in greenhouse warming even if the atmosphere were saturated, because it's the absorption in the thin upper atmosphere (which is unsaturated) that counts
(b) It's not even true that the atmosphere is actually saturated with respect to absorption by CO2,
(c) Water vapor doesn't overwhelm the effects of CO2 because there's little water vapor in the high, cold regions from which infrared escapes, and at the low pressures there water vapor absorption is like a leaky sieve, which would let a lot more radiation through were it not for CO2, and
(d) These issues were satisfactorily addressed by physicists 50 years ago, and the necessary physics is included in all climate models.

The guys at RC go on to write a 2nd article about What Ångström didn’t know.

Ångström was a good scientist but his measurements were made over 100 years ago. In 1900 his CO2 saturation argument was a powerful one because at the time scientists didn't understand how the stratified layers in the atmosphere interact.

Today they do and thus his 'saturated' argument can be explained and dealt with in climate models.

You don't understand anything about this. Only expertise you demonstrate is in "cut and paste".

[WolfattheDoor]

As far as climate change is concerned, did anybody really think the world would make the major changes needed before we see evidence that really affects us?

Restricting transportation, bringing in laws to reduce energy wastage...governments aren't really going to do anything serious until the tides overtop the Thames Barrier or you get hurricanes in Florida in April.

It's all reminiscent of WW2 where they ignored Hitler until the bombs started falling.

[MacG]

It's like having a black curtain over a window. Adding another black curtain wont make the room darker. At about 20 ppm CO2, effectively all IR radiation is captured. The thing follow a logarithmic called Beer's Law. Its impossible to capture more than 100% of the IR radiation.

Everything indicate that CO2 is merely a trailing indicator, not a leading cause.

This hyping of CO2 is just junk science. Some people get some kind of jolt from their reward systems when they think that they act altruistic. Thats all. Please go home and forget this hysteria.

Apparently, it's not like having a black curtain over a window:

So, if a skeptical friend hits you with the "saturation argument" against global warming, here's all you need to say: (a) You'd still get an increase in greenhouse warming even if the atmosphere were saturated, because it's the absorption in the thin upper atmosphere (which is unsaturated) that counts (b) It's not even true that the atmosphere is actually saturated with respect to absorption by CO2, (c) Water vapor doesn't overwhelm the effects of CO2 because there's little water vapor in the high, cold regions from which infrared escapes, and at the low pressures there water vapor absorption is like a leaky sieve, which would let a lot more radiation through were it not for CO2, and (d) These issues were satisfactorily addressed by physicists 50 years ago, and the necessary physics is included in all climate models.

From:

http://www.realclimate.org/index.php/ar ... y-argument


Peter.

They are idiots. The thin upper atmosphere is -40 deg C, and it don't heat anything. Amazing that you believe this crap.

[Bandidoz]

he just keeps saying, "They're all nutters" and refuses to get involved

Awww shame Thanks for asking, though

The guys at RC go on to write a 2nd article about What Ångström didn’t know

Very good....

Some questions:

1) What's the typical bandwidth of IR radiation emitted from the Earth's surfaces? This diagram shows the filter, I'd like to know what the input signal is I'm guessing 8-15um. Surely if it ALL gets blocked then night-vision and thermal imaging cameras wouldn't work?

2) What's the effect of impurities (e.g. water vapour), presumably Ångström's experiments would have been using "pure" air or a vacuum?