2250-MW Navajo coal-fired plant shut down, under demolition

[wwhitney]

P.S. You raise some good questions about things that aren't clear to me as a lay person. And so if we're keeping track, they are slight negative marks against AGW until explained (likely by our learning more of the science). But you often make the rhetorical jump "here's one thing that isn't making sense, so the whole theory is wrong."

That's obviously not how science works. As new science is being discovered, there's data both for and against a hypothesis. You have to weigh all the available evidence to determine what's most likely. One small seemingly negative point does not immediately shift the balance. The theory does not have to be perfected before you conclude it's very very likely to be true. And that's the current state of play on AGW.

Cheers, Wayne

 

[gadfly56]

Sure, but when the physics (per observed atmospheric IR absorption spectra) tells you to expect an effect (temperature rise), and you see the effect, that is generally considered confirmation.


I haven't, actually, I just agreed your graph didn't show any. I'm not enough of a subject matter expert to know if that's the correct graph, or if we should expect acceleration at a detectable level, or if the expected acceleration is still at a level that is drowned out by the noise. You certainly raise a good question, but that's not nearly enough to reject the physics and the evidence.

If you'd like to continue to try to rebut AGW, please address post 95.

Cheers, Wayne

What, you didn't like my graph? Well, not my graph, but you get the idea. From a peak of ~7,000 ppm, while CO₂ steadily declined, temperature stayed the same. From the middle of the Devonian the CO₂ cratered until the early third of the Cretaceous and temperature stayed the same for 40 million years or so. Then temperature rocketed up moving from the Permian to the Triassic, while CO2 lagged the temperature. The Triassic and Jurassic saw temperatures much like the Cambrian, but at CO₂ levels 3X lower.

It's one thing to see the result in a lab, it gets a lot messier once you step outside. Yes, all things being equal, more CO2, more reflected IR to the surface. But the wavelengths are pretty much saturated, as evidenced by the log-normal response for temperature rise. For each linear increase in temperature, you have to double the CO2 concentration.

MODTRAN is a standard scientific package used to model and analyze optical measurements in the atmosphere.

And the actual effect.

I hope everyone is keeping warm. It's wet and in the low 30's here. Very nasty.

 

[Dzboyce]

Washington state is one of the most geologically divers states in the USA. During the last grat ice age, Seattle was covered by glaciers close to a mile thick. Closer to me there are many gladiator valleys. You can tell exactly where the glaciers ended and retreated. An ice dam crated a huge lake in Montana referred to as lake Missoula. Ice makes a terrible day, when the dam broke it flooded northern Idaho and Eastern Washington. Creating channeled scablands. The wall of flood water was estimated to be 700 ft high. It took over a week for the flood waters to escape thru the Columbia gorge to the pacific ocean. This happened not just once, but more than 20 times. We have had three distinctly separate epochs of basalt flows. The Ellensburg, the Wanapum and the Grande Ronde. Cumulatively they are a few thousand to over 14,000 feet thick. Individual flows within each formation can be identified by XRF analysis. The lava predominatly flowed from vents. The lava was estimated to flow at speeds of 20-30 mph. 20 miles to the west of me is some Ellensburg basalt that have petrified wood. Many of the wood species are subtropical.

What caused the Irish potato famine in the 1800's? Didn't almost a third of the people in Ireland immigrate to the USA during the famine. The temperature fell a few degrees in Ireland and potatoes couldn't be grown.

We have a much grater risk of a major temperature change to the earth from natural events. If the Yellowstone Calderon erupts, life as we know it will cease to exist.

 

[wwhitney]

What, you didn't like my graph?

All your 600 million year graph shows is that on that time scale, CO2 is not the most important factor in determining surface temperature. It doesn't show it's not a factor. And for the question of our behavior during this century, the graph from post 44 is far more relevant.

But the wavelengths are pretty much saturated

The relevant wavelength bands are not saturated, which is why emissions matter. If they were saturated in all the bands CO2 absorbs in, I would agree that further CO2 doesn't matter.

Cheers, Wayne

 

[wwhitney]

We have a much grater risk of a major temperature change to the earth from natural events.

The events you mention are, over the next century, low probability, high magnitude possibilities.

AGW is an extremely high probability, cumulative effect--the more we allow it to accumulate, the higher magnitude the effect.

Cheers, Wayne

 

[Dzboyce]

But yet those low probability, high magnitude events reshape the earth. The ash from Mt St Helen's was no fun. As I recall I got 4 inches total in three events in 1980. Some areas got over 12 inches of ash. I have drilled thru over 200 ft of ash pumice deposits on the eastern slopes, of Steven's pass. If mt Rainier becomes active, the mud flows alone would wipe Seattle and Tacoma off the map. Let alone any Pyroclastic ash falls to the east. My area of Washington has had well over 100 events that would have killed all forms of life. Silly humans, we think of tings in terms of 100, maybe 200 years. When that is just an eyeblink in the history of the earth.

 

[wwhitney]

MODTRAN is a standard scientific package used to model and analyze optical measurements in the atmosphere.

Not sure the source of your Modtran graph, but the radiative forcing coefficient it shows does not agree with other sources. The 2.94 coefficient in front of log2(CO2) would be a 4.24 coefficient in front of ln(CO2) [just divide by ln(2)]. And this source shows a coefficient of 5.35:

ACS Advocacy Workshops - American Chemical Society

American Chemical Society: Chemistry for Life.

www.acs.org

As to your "Heating Effects" graph, again you haven't specified the source, nor indicated how the graph was constructed and whether it includes atmospheric feedback effects, which are large. The presentation is also not very informative, since the graph shows the derivative of temperature vs CO2 concentration, and the scale on the y-axis makes it impossible to read the relevant values for our discussion.

If I guess that the relevant tiny bars are 0.05 on the y-axis scale, that's 0.05 degrees C per 20 ppm CO2 increase, where CO2 has increased from about 280 ppm pre-industrial to 410 ppm today. Which would mean ~0.3 C increase. That's a factor of 2 low compared to a simple calculation (without feedback effects) based on coefficients from the following source, and a factor of 3 below the observed temperature rise.

ACS Advocacy Workshops - American Chemical Society

American Chemical Society: Chemistry for Life.

www.acs.org

Cheers, Wayne

 

[winnie]

I wanted to thank everyone for a mind expanding discussion. I don't think that we will change each other's minds, but I think we will all end up a bit wiser.

The graph of CO2 levels and temperature over 600 million years is very instructive.

IMHO it does not refute AGW, but I think it should change the discussion. The graph is of course not based on direct measurements, but proxies, and all of the parameters should have huge error bars. The key take away for me is that even though I believe AGW is happening, there will be feedback limits to the temperature change. In other words, if humanity does its worst and doubles or triples atmospheric CO2, the temperature change will be no more than 10C.

Now 10C is a _huge_ change in average temperature, with major sea level changes, major shifts in distribution of arable land, sifts in rainfall, shifts in plant and animal populations, significant species loss and gain, etc. But it is a survivable shift, and when one looks at the dangers of heat vs cold, a 10C shift in average global temperature might be an improvement for humanity once the transition is complete.

Something that I recall from other discussions on this topic is that in the past other forcing effects (solar or orbital variations) would trigger temperature changes, and that CO2 would _follow_ the temperature changes. The suggestion from this data was that CO2 was part of a positive feedback loop which amplified the temperature changes until other processes clamped the change. Because CO2 was part of a positive feedback loop, the CO2 itself could be the trigger event for a temperature change. Again this speaks to the concept that processes other than CO2 dominate climate change, but that rapid changes in atmospheric CO2 could have strong short term effects.

To my mind, this makes AGW not an existential threat to humanity, but rather something which could cause huge displacement and economic impact.

Another point which I mentioned above, is that separate from the science and data about AGW is our political response to such. It might be 'better' to invest in population resilience to climate change (natural or human caused) than to try to prevent climate change. I personally believe than any 'solution' to AGW must be business and growth positive, rather than growth negative. Figuring this out is a _political_ issue, not science.

-Jon

 

[wwhitney]

Now 10C is a _huge_ change in average temperature, with major sea level changes, major shifts in distribution of arable land, sifts in rainfall, shifts in plant and animal populations, significant species loss and gain, etc. But it is a survivable shift, and when one looks at the dangers of heat vs cold, a 10C shift in average global temperature might be an improvement for humanity once the transition is complete.

That is an interesting theory. If you want to posit that the world economy could be more productive after a 10C temperature rise, then there's still the question of the transition costs, the huge undertaking to relocate people and assets to the now more desirable locations. That would be an economic intervention that makes carbon curbing interventions look trivial.

And what is the payback period going to be after the expense of all this relocation? Perhaps you can develop this into a proposal and we can vote on it, rather than just continue with the unplanned and unintentional geoengineering we are currently doing.

I personally believe than any 'solution' to AGW must be business and growth positive, rather than growth negative.

I think proper accounting is going to show plenty of growth positive AGW mitigation options. Because, you know, 10C temperature rise is likely quite growth negative.

Cheers, Wayne

 

[wwhitney]

The relevant wavelength bands are not saturated, which is why emissions matter. If they were saturated in all the bands CO2 absorbs in, I would agree that further CO2 doesn't matter.

So this is actually not correct, as it conceives of the atmosphere as a single layer or filter. Rather, the atmosphere is a continuum and proper modeling requires at least several layers.

The graph here, of planetary IR emissions as seen from a satellite, overlaid with black body curves for various temperatures, really has a lot to say:

ACS Advocacy Workshops - American Chemical Society

American Chemical Society: Chemistry for Life.

www.acs.org

In the CO2 absorption band, at low altitudes the atmosphere is saturated; basically none of the IR emitted by the earth's surface escapes directly into space. With rising altitude, atmospheric pressure decreases and so too does CO2 partial pressure and hence CO2 IR absorption. Until at a certain altitude, the atmosphere is no longer saturated, and IR emitted at that altitude and above starts to escape into space.

The temperature of the atmosphere at that altitude determines the planet's effectiveness at radiating IR in those frequencies. As this altitude is in the troposphere, temperature is decreasing with altitude. And the greater the atmospheric CO2, the higher the altitude before the CO2 partial pressure is low enough to allow IR in the relevant band to escape. Thus the colder the earth's effective black body temperature in that frequency band, and the less IR emitted. Which means more energy retained, and therefore higher temperature on the earth's surface.

Cheers, Wayne

 

[tortuga]

Interesting graphs and read, slightly over my head, but I still think AGW is like the old second hand smoke debate:
Just like there is no minimum daily value of second hand smoke needed for human survival.
There is no minimum amount of CO2 we need to put in the sky for the planet to be livable, so we should cut back.
There is a minimum amount of CO2 needed to warm Mars so perhaps we'll move heavy industry there?

 

[wwhitney]

There is a minimum amount of CO2 needed to warm Mars so perhaps we'll move heavy industry there?

Now that's what I call carbon sequestration. : - )

Cheers, Wayne

 

[gadfly56]

Interesting graphs and read, slightly over my head, but I still think AGW is like the old second hand smoke debate:
Just like there is no minimum daily value of second hand smoke needed for human survival.
There is no minimum amount of CO2 we need to put in the sky for the planet to be livable, so we should cut back.
There is a minimum amount of CO2 needed to warm Mars so perhaps we'll move heavy industry there?

If it hits 150ppm, the plants die, then we die.

 

[winnie]

An amusing thought that I've had: it is something of a conceit to think that human actions are not natural.

Other organisms have changed the environment, sometimes to their own detriment. The original organisms that created our lovely oxygen atmosphere found oxygen toxic.

On the assumption that CO2 is changing the environment in a way that is bad for humans: perhaps that is simply part of the natural chain of events by which we prepare the planet for the next stage. Perhaps the plan is for us to change the environment until we fight it out in a nuclear war, to prepare the planet for the evolution of the cockroach

-Jon

 

[drcampbell]

If it hits 150ppm, the plants die, then we die.

I'm going to file this one under "Potential catastrophes I'm least like to lose sleep over." Right beside the abolition of Daylight Saving Time.

 

[jaggedben]

If it hits 150ppm, the plants die, then we die.

Humans don't need to put CO2 into the atmosphere to maintain that. Not in our lifetimes anyway, and if it ever came to it we'd have the technology.

 

[gadfly56]

Humans don't need to put CO2 into the atmosphere to maintain that. Not in our lifetimes anyway, and if it ever came to it we'd have the technology.

During the last glaciation, it came darn close, about 180 ppm. Now, not an issue even for my great-great grandchildren (if any), but well within the threat horizon for our species.

 

[tortuga]

Well in the next few hundred years when were on commercial fusion/ renewables our great great grandchildren will have to start watching those levels, unless they are too busy wiring mars or maintaining asteroid mining colonies.