Why CO2 does not govern the earth's surface temperature

No, it is specifically CO2 whose effect is minimal at the earth's surface because water vapor is so much more abundant there, and so powerfully absorptive in most of CO2's IR absorption wavelengths; and it is specifically greenhouse gases that act like blankets, not the climate system. The warmth of the earth's surface is due to two entirely different effects of the atmosphere: most importantly, the Combined Gas Law that relates pressure and temperature to yield the adiabatic lapse rate, and less importantly, the misnamed "greenhouse effect," which impedes the emission of IR radiation from the earth's surface to outer space (actual greenhouses work by blocking convection, not radiation).

 

Its estimated that the total greenhouse effect is about 50 degrees with most of that being CO2. CO2 is much smaller but does increase the temperature by a few degrees. Increasing CO2 is enough to also kick off some climate feedbacks as well to increase the temperature even more.

 

That estimate is absurd, and not based on any credible physical reasoning I am aware of. The vast majority of the greenhouse effect is due to water vapor, not CO2, because water vapor is two orders of magnitude more abundant in the atmosphere than CO2, and absorbs in a broader portion of the IR spectrum.

Wait, what? Did you mean water vapor? In the first sentence or the second?

CO2's contribution is limited by the fact that the temperature response is logarithmic, most of the ~50C greenhouse effect is accounted for by water vapor, and there is already ~400ppm of CO2 in the air. If we assume ECS of 3C, roughly the middle of the IPCC's claimed range, then reducing CO2 to 200ppm would reduce surface temperature by 3C. At 100ppm, it would be down 6C. At 50ppm, 9C. At 25ppm, 12C. Do you see where this is going? If ECS is really 3C, then well before 0% CO2, the earth's surface temperature would be lower than if there was no CO2 at all! It's self-evidently physical nonsense. Because of this mathematical relationship, ECS CANNOT be more than about 1C, and may be quite a bit less.

I have explained why it isn't. CO2's greenhouse contribution is only significant where very low temperature (< -20C) has condensed almost all the water vapor out of the air: at high altitude, and high latitude in winter. And water vapor prevents CO2's greenhouse warming at high altitude from propagating back down to the earth's surface except on the highest mountains and in winter at high latitude, places where we really don't mind if it gets a little warmer.

 

Sorry about that, I did mean water vapor making up most of that 50 degrees. One thing you are ignoring are climate feedbacks. Huge climate changes are often started by small orbital changes that don't change the temperature much on their own, but feedbacks create a snowball effect.

 

Positive feedbacks are an issue, and the main one is the ice-albedo feedback that causes the ~100Ky glacial cycle. But most of the strongest feedbacks are negative, or the climate could not be as stable as it is. I've seen no credible argument for powerful positive feedbacks other than the ice-albedo feedback. The strong positive water vapor feedback assumed in all CAGW modeling is not based on any credible empirical science or physical reasoning.

 

Frankly, if we didn't have a lot of positive feedbacks, we wouldn't see temperature go up and down in the past as much as it does. Historic temperatures would be a lot more stable.

One positive feedback are greenhouse gasses. There is a lot of CO2 in the ocean, CO2 and methane in the ice, and other places. When the planet heats up, many of these get released which warms the planet even more. Water vapor, a greenhouse gas, itself is one because hotter temperatures cause more evaporation and hotter air can cold more water. The ice albeto that you mentioned is another one. Clouds are a negative feedback because hotter temperatures release water, creating more clouds, and clouds cool things down. There are a bunch of other feedbacks. Climatologists agree that overall, feedbacks tend to be positive. Thats how we get out of ice ages.

 

Nope. The relative stability of temperatures when the positive ice-albedo feedback is not involved shows that negative feedbacks dominate. In particular, the predictability of the seasons shows that the main sources of short-term variation are external and astronomical, not internal positive feedback mechanisms.

But the timing of the ice ages shows it is at most very minor compared to the ice-albedo feedback.

A little more. Not enough to affect the timing of the ice ages. I have explained why the dominance of water vapor's greenhouse effect in the lower troposphere prevents other greenhouse gases from having much effect on surface temperature.

For temperatures in the normal range (>0C) the increase in water vapor content of the air with temperature is so small that the feedback can be ignored.

It is by far the most important one, and is the major source of the long-term instability that causes ice ages.

Right. That is probably the negative feedback that has capped the earth's temperature in the past.

If they do, which I doubt, then they are just stupid. If positive feedbacks dominated, the earth would long ago have turned into either a snowball or a cinder.

There is one positive feedback that gets us out of ice ages -- the ice-albedo feedback -- and it is effective only over a certain range of temperature and latitude.

 

You claims that temperatures are really stable but that simply isn't true.


As you can see, temperatures bounce around wildly between ice ages and warm periods. If negative feedbacks dominated then temperatures would be very flat as warming/cooling would begin to be reversed by negative feedbacks.

 

Of course it's true.


As you can see, temperatures bounce around wildly between ice ages and warm periods.[/quote]
No they don't. They follow a regular cyclical pattern that matches known orbital cycles because of external astronomical forcing, not internal positive feedbacks.

Nope. We know that aside from the positive ice-albedo feedback, negative feedbacks have to dominate because the up and down trends stop and then reverse in time with the astronomical forcing, instead of continuing up or down on their own. Basic control theory.

 

So it sounds like you are saying that during an ice age the sun cooled enough to cause an 8 degree dip in global temperatures?

 

Some of the greatest scientific minds of our time, sucked into the climate change environment?
Makes no sense.

 

Many of the greatest minds of all time have been religious believers. That makes no sense either. Never underestimate the power of the collective to enforce conformity of belief.

 

No, it doesn't sound like I am saying that. The ice ages are caused by changes in the earth's orbit, not the sun, and the effect of those changes on temperature is exaggerated by the positive ice-albedo feedback effect. As I have already explained so very clearly and patiently, multiple times, in simple, grammatical English.

 

Do you have any evidence that the positive ice-albedo effect is purely responsible for ice ages and greenhouse gasses (including water vapor) aren't involved at all?

 

That is a poor argument.
Some have believed one thing, therefore these others also believe something else?
Not buying it.

 

No, they have believed all manner of socially approved nonsense.

Socially approved nonsense in both cases. Coincidence?

 

Two strawman fallacies in one sentence. Nice.

 

I'm not intentionally mischaracterizing you. Feel free to correct me.

 

The Globe’s Total Greenhouse Effect Forcing Has Been On A Declining Trend For Decades
By Kenneth Richard on 8. February 2021

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CO2’s impact on the total net greenhouse effect (GHE) or longwave (LW) forcing trend has been offset by the dominant impact of cloud cover since the 1980s.
It is now widely accepted that changes in clouds, naturally driven by changes in atmospheric circulation, “may be the most important parameter controlling the radiation budget, and, hence, the Earth climate” (Sfîcă et al., 2021). Indeed, in recent decades, the post-1980 +3 W/m² increase in absorbed solar radiation due to the reduction in cloud albedo (Delgado-Bonal et al, 2020) can explain the warming in recent decades.



Image Source: Sfîcă et al., 2021
An overlooked 2020 observational study (Su et al., 2020) suggested that while top of the atmosphere (TOA) shortwave (SW) forcing has risen at a rate of +0.61 W/m² per decade since the early 2000s (because “decreasing cloud optical depth…causes an overall increase in TOA SW flux”), the total longwave (LW) or greenhouse effect (GHE) forcing – which includes the total net forcing impact of CO2 – has declined at a rate of -0.17 W/m² per decade. . . .

 

The ice-albedo effect magnifies the Milankovitch astronomical/orbital forcing; it's not clear which effect contributes more. CO2 and CH4 are involved to some minor degree.

 

Okay, so CO2 and CH4 are only minor and the primary feedback is albeto. Do you have any research that supports this?

 

The fact that the glacial cycle is accompanied by only minor changes in CO2 and CH4 flat-out proves it, with no further research needed.

 

But the graph I showed you shows CO2 concentrations bouncing around between 200 and 300 PPM between glacial ages. That doesn't sound minor to me. What gives?

 

Math. Variation between 200-300ppm is minor because we are now at 420ppm and it still hasn't made much difference to temperature. I already explained why ECS can't be more than about 1C. That makes a change of 100ppm minor.

 

New factor in the carbon cycle of the Southern Ocean identified
Charles Rotter
“In doing so, we were able to demonstrate for the first time a manganese limitation for phytoplankton growth in the center of Drake Passage. Closer to shore, iron was the…

". . . Earlier research suggests that greater phytoplankton growth in the Southern Ocean was a key contributor to the onset of the ice ages over the past 2.58 million years. More phytoplankton was able to bind more CO2, which was removed from the atmosphere. As a result, average global temperatures further declined. “So it’s critical that we understand exactly what processes regulate phytoplankton growth in the Southern Ocean,” Dr. Browning points out. . . .

After the expedition, the team used additional model calculations to assess the implications of the experimental results. Among other things, they found that manganese limitation may have been even more widespread during the ice ages than it is today. “This would make this previously unaccounted for factor a central part of understanding the ice ages,” says Dr. Browning. . . ."