Global Warming Cont...

[saltydawg]

http://news.yahoo.com/s/ap/20090116/...winter_weather



He likes it ->

January heat wave hits California. Santa is wearing a t-shirt and cut-off jeans.


http://www.dailybruin.ucla.edu/news/...s-los-angeles/

He likes it - >

[Guisslapp]

I see what you are saying. I take that to mean the atmosphere is a complex system so it is impossible to figure it down to the millionth decimal point the temperature of the surface even assuming a constant solar input. Is that close?

Not exactly, but you couldn't calculate the mythical average temperature of the Earth to a single degree even if you knew the composition of the Earth's atmosphere and the day of the year using these people's models. Way too many other factors affect temperature.

My point was that you cannot just start with a formula for radiation (like Stefan-Boltzmann law), and then fold in other physical laws to produce a master equation for Temperature as a function of CO2 concentration (along with other variables). It is not a problem that can be solved analytically. The solution must be empirical (done by statistical correlation), and it cannot be proven algebraically.

[arkansasbob]

And now I'm asking you if you have an opinion as a chemical engineer on that question. Not only that, but to explain your answer.

Like you said, I would tell you what the conventional wisdom is per scientists who study the atmosphere. It's obvious that I think CO2 plays a role in keeping the Earth warm per their statements.

i don't have an opinion on the subject as a chemical engineer. as a critical observer with a somewhat scientific background, here are the facts:

- co2 absorbs radiant heat in the form of ir radiation, but not uv or visible light. as a result, it will absorb some energy from the earth as it irradiates heat absorbed from the sun.
- there are many aspects of the atmosphere and universe, including water vapor, clouds, convection, thunderstorms, and changes in the sun that have an impact on climate, local and global, that is easily observable (although the impact of individual factors cannot be easily quantified with much precision because of the overwhelming number of other factors involved).
- i have never heard nor read of any observation of the climate being affected by changes in co2 concentration (other than the claim, "temperatures are rising and so is co2, so they must be related").
- guisslapp says that co2 comprises about 3.6% of the greenhouse effect on the earth's atmosphere. i imagine this is quantified by taking the rate of ir absorption of each known greenhouse gas and multiplying it by the estimated concentration of that gas in the atmosphere. this is probably accurate as far as it goes, but it fails to take into account the greenhouse effect of clouds (they absorb and reflect a large amount of sunlight, but they allow quite a bit through and trap virtually all radiation coming back from the earth). it also tells us nothing of how much effect these combined greenhouse gases have on the climate as a whole.
- many talented scientists (most with a desire to prove the idea of runaway [there's a word we haven't heard in a while...] global warming caused by rising co2) have attmepted to model global temperatures to predict future affects of rising co2. it has been long enough since these models first ran for us to see that they were completely wrong and a total failure at modeling the overall effects of greenhouse gases. my guess is that the margin of error in their assumptions is enough to make their models predict a wide range of outcomes and they simply adjusted their assumptions to give the results they wanted. this is evinced by the fact that many predict a sudden catastrophic cooling rather than runaway warming. funny that none of them predict somewhat normal long-term temperature patterns...

there are other facts that bear on my opinion, but those are the big ones that come to mind. the conclusion i draw is that there is insufficient evidence to claim that co2 has a significant impact on global climate in the concentrations in which it is present, and that there is sufficient evidence that other factors (especially sun spot cycles) have a much more significant effect. it is also reasonable to believe that even if the global climate is significantly effected by co2, it will not be nearly as bad as the alarmists are predicting, and money and research would be better spent detemining a way to adapt and take advantage of the coming climate change rather than crippling an already sick economy by forcing expensive greenhouse emissions limits and controls.

[Guisslapp]

- guisslapp says that co2 comprises about 3.6% of the greenhouse effect on the earth's atmosphere. i imagine this is quantified by taking the rate of ir absorption of each known greenhouse gas and multiplying it by the estimated concentration of that gas in the atmosphere.

Yes, that is essentially what it is.

[Dirtydawg]

http://news.yahoo.com/s/ap/20090116/...winter_weather



He likes it ->

Well, what do you expect? It's getting so hot in the arctic that even the cold air wants to leave.

[saltydawg]

i don't have an opinion on the subject as a chemical engineer. as a critical observer with a somewhat scientific background, here are the facts:

- co2 absorbs radiant heat in the form of ir radiation, but not uv or visible light. as a result, it will absorb some energy from the earth as it irradiates heat absorbed from the sun.
- there are many aspects of the atmosphere and universe, including water vapor, clouds, convection, thunderstorms, and changes in the sun that have an impact on climate, local and global, that is easily observable (although the impact of individual factors cannot be easily quantified with much precision because of the overwhelming number of other factors involved).
- i have never heard nor read of any observation of the climate being affected by changes in co2 concentration (other than the claim, "temperatures are rising and so is co2, so they must be related").
- guisslapp says that co2 comprises about 3.6% of the greenhouse effect on the earth's atmosphere. i imagine this is quantified by taking the rate of ir absorption of each known greenhouse gas and multiplying it by the estimated concentration of that gas in the atmosphere. this is probably accurate as far as it goes, but it fails to take into account the greenhouse effect of clouds (they absorb and reflect a large amount of sunlight, but they allow quite a bit through and trap virtually all radiation coming back from the earth). it also tells us nothing of how much effect these combined greenhouse gases have on the climate as a whole.
- many talented scientists (most with a desire to prove the idea of runaway [there's a word we haven't heard in a while...] global warming caused by rising co2) have attmepted to model global temperatures to predict future affects of rising co2. it has been long enough since these models first ran for us to see that they were completely wrong and a total failure at modeling the overall effects of greenhouse gases. my guess is that the margin of error in their assumptions is enough to make their models predict a wide range of outcomes and they simply adjusted their assumptions to give the results they wanted. this is evinced by the fact that many predict a sudden catastrophic cooling rather than runaway warming. funny that none of them predict somewhat normal long-term temperature patterns...

there are other facts that bear on my opinion, but those are the big ones that come to mind. the conclusion i draw is that there is insufficient evidence to claim that co2 has a significant impact on global climate in the concentrations in which it is present, and that there is sufficient evidence that other factors (especially sun spot cycles) have a much more significant effect. it is also reasonable to believe that even if the global climate is significantly effected by co2, it will not be nearly as bad as the alarmists are predicting, and money and research would be better spent detemining a way to adapt and take advantage of the coming climate change rather than crippling an already sick economy by forcing expensive greenhouse emissions limits and controls.

Clearly, at some point in the future, if CO2 is allow to increase at its present rate, the shit will hit the climate fan.

There is plenty of evidence to establish that increasing amounts of Co2 in the atmosphere will increase surface temperatures. The natural greenhouse effect on Earth is well understood and accepted. It also operates on Venus and Mars. Basically, thermal radiation from the planet must equal the solar radiation coming in. Do you agree with that? This is important: thermal radiation from the planet must equal the solar radiation coming in.

So, if we add CO2 to the atmosphere we are basically reducing the ability of the atmosphere to radiate thermal energy. Consequently, the surface temperature has to increase in order to over come the additional restriction place on the atmosphere to radiate heat because of increased levels of atmospheric co2. As more and more co2 is added to the atmosphere, the surface temperature has to get hotter and hotter in order to maintain the balance between solar radiation coming in and thermal radiation leaving the planet.

BTW, there will never be a "runaway" greenhouse effect here on Earth because the greenhouse effect is halted when water vapor is in equilibrium with ice or liquid water. There is probably some law out there that governs that relationship.

[arkansasbob]

Clearly, at some point in the future, if CO2 is allow to increase at its present rate, the shit will hit the climate fan.

There is plenty of evidence to establish that increasing amounts of Co2 in the atmosphere will increase surface temperatures. The natural greenhouse effect on Earth is well understood and accepted. It also operates on Venus and Mars. Basically, thermal radiation from the planet must equal the solar radiation coming in. Do you agree with that? This is important: thermal radiation from the planet must equal the solar radiation coming in.

So, if we add CO2 to the atmosphere we are basically reducing the ability of the atmosphere to radiate thermal energy. Consequently, the surface temperature has to increase in order to over come the additional restriction place on the atmosphere to radiate heat because of increased levels of atmospheric co2. As more and more co2 is added to the atmosphere, the surface temperature has to get hotter and hotter in order to maintain the balance between solar radiation coming in and thermal radiation leaving the planet.

i'm proud that you seem to understand a simple energy balance (something even texas a&m chemical engineers seem to have trouble with). the problem is that this balance isn't so simple. if co2 was the only factor affecting radiation to and from the earth, then it would be. but it's not. there are scores of other factors that affect the amount of radiation the earth receives, as well as the amount of radiation that escapes.

BTW, there will never be a "runaway" greenhouse effect here on Earth because the greenhouse effect is halted when water vapor is in equilibrium with ice or liquid water. There is probably some law out there that governs that relationship.

this, you obviously don't understand and would be wise to keep your mouth shut.

[saltydawg]

Explain about the "runaway" greenhouse effect and how it could occur here on Earth.

[arkansasbob]

Explain about the "runaway" greenhouse effect and how it could occur here on Earth.

i don't know how it could. i just know that i heard that phrase at least 10 times a week during the 90's and early 00's. i believe the idea was that we create a positive feedback loop where the co2 makes the atmosphere warmer, which melts the polar ice caps, which causes the earth to absorb more solar radiation (due to having less ice reflecting the light back into space), which causes global temperatures to rise, which melts more ice, etc.

this was the source of the original global warming greenhouse gas scare. alarmists have wisely shied away from this notion now that it appears negative feedback confounds the greenhouse effect, moderating temperatures.

[saltydawg]

i don't know how it could. i just know that i heard that phrase at least 10 times a week during the 90's and early 00's. i believe the idea was that we create a positive feedback loop where the co2 makes the atmosphere warmer, which melts the polar ice caps, which causes the earth to absorb more solar radiation (due to having less ice reflecting the light back into space), which causes global temperatures to rise, which melts more ice, etc.

this was the source of the original global warming greenhouse gas scare. alarmists have wisely shied away from this notion now that it appears negative feedback confounds the greenhouse effect, moderating temperatures.

Probably they were confusing a positive feedback loop with a "runaway" feedback loop. A runaway feedback loop will never occur here on Earth as far as the greenhouse effect is concerned.

Yes, there are both positive and negative feedback loops in regards to global warming. But the basic model of thermal radiation from the planet must equal the solar radiation coming in remains intact. Since we don't apparently know what the heck is going to happen with increasing levels of atmospheric CO2, are you a little bit concerned about the long-term outcome of this science experiment that will soon get out of our control?

[dawg80]

Well, what do you expect? It's getting so hot in the arctic that even the cold air wants to leave.

That's as worthy a scientific argument as the GW advocates advance.

[Guisslapp]

Probably they were confusing a positive feedback loop with a "runaway" feedback loop. A runaway feedback loop will never occur here on Earth as far as the greenhouse effect is concerned.

Yes, there are both positive and negative feedback loops in regards to global warming. But the basic model of thermal radiation from the planet must equal the solar radiation coming in remains intact. Since we don't apparently know what the heck is going to happen with increasing levels of atmospheric CO2, are you a little bit concerned about the long-term outcome of this science experiment that will soon get out of our control?

What is the difference of a positive feedback loop and a "runaway" feedback loop?

[saltydawg]

What is the difference of a positive feedback loop and a "runaway" feedback loop?

The positive feedback loop stops after the first lap.

[arkansasbob]

The positive feedback loop stops after the first lap.

???

[Guisslapp]

Yes, there are both positive and negative feedback loops in regards to global warming. But the basic model of thermal radiation from the planet must equal the solar radiation coming in remains intact. Since we don't apparently know what the heck is going to happen with increasing levels of atmospheric CO2, are you a little bit concerned about the long-term outcome of this science experiment that will soon get out of our control?

Clouds play a much bigger role on how much radiation is emitted from Earth.

Salty, you might have fun playing with this MODTRAN model -

http://geosci.uchicago.edu/~archer/c...radiation.html