APOD: Global Warming Predictions (2009 April 21)

[Czerno]

- Since it is a heavier than air gas, gravity will tend to concentrate it a low atmospheric layer and be absorbed by vegetation on land, and dissolved in ocean waters.

= No, this doesn't happen. There is no stratification of gases in the atmosphere below about 100 km, because the mixing rate is very high. Above 100 km there is little mixing, and gases start stratifying according to their molar mass.

Point taken, my notion of a concentration gradient was mistaken, but it's not important to the argument. Surely as CO2 from the lower layer is removed by absorption and dissolution processes, it is replaced by molecules from immediately higher which in turn will be candidate for removal. In the end surely the equilibrium is displaced, but only so much so - and since there is not much more fossil carbon for us to find and burn, the catastrophic warming point of view seems really far fetched. When is that next ice age coming, BTW ?

[BMAONE23]

The ramifications of the worse case change over the next century are completely devastating.

This is probably the number one biggest lie in the entire issue. We know that climate will change, history and geology tell us that it does. You and others are telling us that a warmer world will be "devastating"! Really? Longer growing seasons? More CO2 and more rain to increase agricultural yields? More higher latitude land available for agriculture? Less ice and snow? More fresh water? These things are devastating? Telling us that global warming will be devastating is The Big Lie.

The worst thing projected by "Global Warming" is sea level rise. An optimal response would be to plan for it.

A Sea Level rise of just a few meters would be devistating to many coastal cities. A Sea Level rise of 10 meters would be devistating to over 600 million people
http://www.emporia.edu/earthsci/student ... 1proj.html
The most fertile parts of the Sacramento Valley and San Joaquin Valley sit at or within 25 meters of sea level with the majority of producers lower than 20 meters above sea level.


So YES, if you make things much warmer you loose too much to be easily recovered from or prepaired for. You can't plant crops in areas that haven't adjusted to the new climate induced growing zones yet nor can you relocate cities containing over 600 million people. (what do you think it would take to build a 30 meter wall around New York? Or to build a 30 meter levee systam along the entire Potomak? What if construction were completed allowing for a 30 meter raise but the oceans rose 40?

It is better to do all we can to avoid this happening rather than forcing massive construction/reconstruction projects.
Better to be proactive than reactive

[StACase]

A Sea Level rise of just a few meters would be devistating to many coastal cities. A Sea Level rise of 10 meters would be devistating to over 600 million people
http://www.emporia.edu/earthsci/student ... 1proj.html
The most fertile parts of the Sacramento Valley and San Joaquin Valley sit at or within 25 meters of sea level with the majority of producers lower than 20 meters above sea level.
...
So YES, if you make things much warmer you loose too much to be easily recovered from or prepaired for. You can't plant crops in areas that haven't adjusted to the new climate induced growing zones yet nor can you relocate cities containing over 600 million people. (what do you think it would take to build a 30 meter wall around New York? Or to build a 30 meter levee systam along the entire Potomak? What if construction were completed allowing for a 30 meter raise but the oceans rose 40?

It is better to do all we can to avoid this happening rather than forcing massive construction/reconstruction projects.
Better to be proactive than reactive

Sea level might go up two feet in a hundred years, read the IPCC Assessement reports.
I think we can handle two feet.

[BMAONE23]

Tell that to Lousiana or Mobile Alabama the next time a storm like Katrina comes along with a sea level just 2 feet higher. Raise the sea level 2 feet and a catagory 3 storm is all that is needed to cause the flooding seen in that catagory 4 storm.

[Chris Peterson]

Point taken, my notion of a concentration gradient was mistaken, but it's not important to the argument. Surely as CO2 from the lower layer is removed by absorption and dissolution processes, it is replaced by molecules from immediately higher which in turn will be candidate for removal. In the end surely the equilibrium is displaced, but only so much so - and since there is not much more fossil carbon for us to find and burn, the catastrophic warming point of view seems really far fetched. When is that next ice age coming, BTW ?

The whole point is that we're upsetting the natural equilibrium. We've apparently saturated the natural removal mechanisms, which is why atmospheric CO2 concentrations are rising. Why do you think we're running out of fossil carbon? Petroleum may be peaking, but there's still a good bit to burn. And there is a century or more of coal, which is just about the worst for CO2 release.

Nobody knows when the next glacial period will arrive, but these come and go over much longer periods than a century. As I've noted before, the problem isn't the absolute rise in temperature (or fall in the case of an glacial period), but the rate it occurs. A few degrees over a century places huge stresses on mankind.

[Chris Peterson]

Sea level might go up two feet in a hundred years, read the IPCC Assessement reports.
I think we can handle two feet.

Many of the scientists working on global climate studies, including many who were part of the IPCC report, complain that the report is far too conservative, and doesn't sufficiently emphasize the poorer outcomes. That said, a two foot rise in sea level over a century seems to me something that we would be unlikely to handle. Just a couple of inches is enough to cause tens of billions of dollars of increased storm damage in the U.S. every few years. A couple of feet essentially gets rid of Florida and much of the Gulf Coast, as well as a several miles along most of the East coast. It takes out major cities all over the world, and eliminates thousands of square miles of land that is currently occupied. A hundred years isn't long enough to absorb the political and economic effects that would likely occur.

[StACase]

Sea level might go up two feet in a hundred years, read the IPCC Assessement reports.
I think we can handle two feet.

Many of the scientists working on global climate studies, including many who were part of the IPCC report, complain that the report is far too conservative, and doesn't sufficiently emphasize the poorer outcomes. That said, a two foot rise in sea level over a century seems to me something that we would be unlikely to handle. Just a couple of inches is enough to cause tens of billions of dollars of increased storm damage in the U.S. every few years. A couple of feet essentially gets rid of Florida and much of the Gulf Coast, as well as a several miles along most of the East coast. It takes out major cities all over the world, and eliminates thousands of square miles of land that is currently occupied. A hundred years isn't long enough to absorb the political and economic effects that would likely occur.

The sky is falling and there's a boogey man living in the basement. Must be terrible to live with your knowledge.

[Chris Peterson]

The sky is falling and there's a boogey man living in the basement. Must be terrible to live with your knowledge.

What you don't know (or refuse to see) can, in fact, hurt you.

[BMAONE23]

Sea level might go up two feet in a hundred years, read the IPCC Assessement reports.
I think we can handle two feet.

Many of the scientists working on global climate studies, including many who were part of the IPCC report, complain that the report is far too conservative, and doesn't sufficiently emphasize the poorer outcomes. That said, a two foot rise in sea level over a century seems to me something that we would be unlikely to handle. Just a couple of inches is enough to cause tens of billions of dollars of increased storm damage in the U.S. every few years. A couple of feet essentially gets rid of Florida and much of the Gulf Coast, as well as a several miles along most of the East coast. It takes out major cities all over the world, and eliminates thousands of square miles of land that is currently occupied. A hundred years isn't long enough to absorb the political and economic effects that would likely occur.

The sky is falling and there's a boogey man living in the basement. Must be terrible to live with your knowledge.

It is interesting how, when the relatively intelligent yet uninformed pseudo intellectual runs out of personally perceived valid arguments, they often resort to derogatory comments in an attempt to cast their opposition into a more pallid light than they fear themselves to be arguing from.

[Dr. Skeptic]

Innocent until proven guilty is a a hard sell with billions of lives at stake.

How many lives do you think would be at stake if we start wars over CO2 regluation?

A two foot rise in sea level would conservatively displace 27of 150 + million people from Bangladesh to other stressed areas, sounds like the makings of war to me.

There are no wars on a dead planet, in the end, the road to ruins is of no consequence.

[gpobserver]

BMAONE23 wrote:

"It is interesting how, when the relatively intelligent yet uninformed pseudo intellectual runs out of personally perceived valid arguments, they often resort to derogatory comments in an attempt to cast their opposition into a more pallid light than they fear themselves to be arguing from."

You should know. That's exactly what you're doing with that statement Mr. Relatively Intelligent Yet Uninformed Pseudo Intellectual.

[aristarchusinexile]

sounds like the makings of war to me.

Only if competing parties see that there is money to be made on the migration .. in Babylon is found the blood of all who were killed on the earth.

[Czerno]

Nobody knows when the next glacial period will arrive, but these come and go over much longer periods than a century.

A very surprising statement. Are you telling me (on an astronomy forum) the triumphs of celestial mechanics and calculus of perturbations, from say Lagrange to Poincaré, joined to the advances in numerical methods (in large part due to astronomers rather than pure mathematicians) and less importantly but conveniently the progress of electronic computing, add to this the accumulated measurements of initial parameters and physical constants to an incredible accuracy of more than 8 decimal figures, have not allowed us to predict the parameters of terrestrial orbit with precision over at least thousand of centuries ? You should know very exactly when this cold age is coming. I have not had time for a search but I think I read it's a matter of a couple centuries. II wondered why you eluded the question, twice. Now I have an idea : is it because you feared your cherished but flaky climate models, giving zero to one half decimal digit precision over a period of ten couple years look ridiculous in the face of the nearly 10 decimals in precise astronometry ? Just kidding. I do not despise computer modeling (I'm a computer scientist myself) but the truth is, models such as take many adjustable and not measurable precisely (or at all) parameters , have hardly more predictive power in them than the oracles of Dephi's pythia.

As I've noted before, the problem isn't the absolute rise in temperature (or fall in the case of an glacial period), but the rate it occurs. A few degrees over a century places huge stresses on mankind.

"A few degrees" is huge and unproven, it would appear.

Regards

[Dr. Skeptic]

sounds like the makings of war to me.

Only if competing parties see that there is money to be made on the migration .. in Babylon is found the blood of all who were killed on the earth.

If AGW turns to be true, it is the ensuing wars over resources that will be the killer of man more so than starvation and disease.

[Chris Peterson]

Nobody knows when the next glacial period will arrive, but these come and go over much longer periods than a century.

A very surprising statement. Are you telling me (on an astronomy forum) the triumphs of celestial mechanics and calculus of perturbations, from say Lagrange to Poincaré, joined to the advances in numerical methods (in large part due to astronomers rather than pure mathematicians) and less importantly but conveniently the progress of electronic computing, add to this the accumulated measurements of initial parameters and physical constants to an incredible accuracy of more than 8 decimal figures, have not allowed us to predict the parameters of terrestrial orbit with precision over at least thousand of centuries ? You should know very exactly when this cold age is coming. I have not had time for a search but I think I read it's a matter of a couple centuries. II wondered why you eluded the question, twice. Now I have an idea : is it because you feared your cherished but flaky climate models, giving zero to one half decimal digit precision over a period of ten couple years look ridiculous in the face of the nearly 10 decimals in precise astronometry ? Just kidding. I do not despise computer modeling (I'm a computer scientist myself) but the truth is, models such as take many adjustable and not measurable precisely (or at all) parameters , have hardly more predictive power in them than the oracles of Dephi's pythia.

Sorry, I can't quite figure out what you're talking about. There's certainly nothing to suggest an Ice Age in the next few centuries. A lot is known about glacial and interglacials, much of it tied to the orbital dynamics of the Earth. There are clear patterns to the cycles, and in the absence of perturbing factors (which, in fact, given our CO2 output aren't absent at all) we might reasonably predict the current interglacial to end in 5 or 10 thousand years, and a new glacial period to follow. Ice Ages don't come or go over periods of a century; it makes no sense to consider them in the context of AGW.

"A few degrees" is huge and unproven, it would appear.

Nothing is proven. A few degrees is what most of the models predict. A few predict a little less than that, a few are quite a bit more than that. None predict a drop in temperature. It's a value with an uncertainty attached. But for a lot of us, the uncertainty is small enough to justify that ameliorative action be taken.

[Indigo_Sunrise]

You should know. That's exactly what you're doing with that statement Mr. Relatively Intelligent Yet Uninformed Pseudo Intellectual.

And so should you. That's all you've done............

[Czerno]

Sorry, I can't quite figure out what you're talking about. There's certainly nothing to suggest an Ice Age in the next few centuries. A lot is known about glacial and interglacials, much of it tied to the orbital dynamics of the Earth. There are clear patterns to the cycles, and in the absence of perturbing factors (which, in fact, given our CO2 output aren't absent at all) we might reasonably predict the current interglacial to end in 5 or 10 thousand years, and a new glacial period to follow. Ice Ages don't come or go over periods of a century; it makes no sense to consider them in the context of AGW.

You obviously remember even less than I do myself about the cycles. IIRC, the "normal" state of the planet is glaciary; interglaciary periods such as the one we are lucky to be living in last for on the order of 10 thousand years, whereas glacial times last for ~ 100 kilo years. Unfortunately we are nearing the end of the interglaciary (which BTW has seen the rise of man possibly not out of a coincidence). It's not 10 thousand years from now, rather a matter of 1 or 2 centuries (ICBW, which is why I asked in the first place. I'm sure my 2 centuries is a much better estimate than your 100 centuries, however!)



And of course it's entirely tied to secular variations in orbital parameters, which are well understood and entirely predictable and calculable.

[gpobserver]

Chris Peterson wrote:

"There's certainly nothing to suggest an Ice Age in the next few centuries. A lot is known about glacial and interglacials, much of it tied to the orbital dynamics of the Earth. There are clear patterns to the cycles, and in the absence of perturbing factors (which, in fact, given our CO2 output aren't absent at all) we might reasonably predict the current interglacial to end in 5 or 10 thousand years, and a new glacial period to follow."

You might wish to re-think that assertion. Ice ages last typically about 100,000 years and interglacials about 10,000 years. We're currently 10,500 years into the current interglacial. A helpful discussion and summary of recent climate history may be found at http://www.esd.ornl.gov/projects/qen/nerc130k.html. You'll notice that transitions may be relatively brief and there are often oscillatory swings of considerable amplitude. One may wonder if the Little Ice Age was such a swing and if we may be close to the end of the current interglacial.

[Chris Peterson]

You obviously remember even less than I do myself about the cycles. IIRC, the "normal" state of the planet is glaciary; interglaciary periods such as the one we are lucky to be living in last for on the order of 10 thousand years, whereas glacial times last for ~ 100 kilo years.

Who cares what's "normal"? What matters is if we're currently pushing the climate too far and too fast for our societies to adapt. And the evidence suggests that there's a good possibility of that. Natural, long term climate cycles are irrelevant to the discussion.

Unfortunately we are nearing the end of the interglaciary (which BTW has seen the rise of man possibly not out of a coincidence).

Assuming we are (which is far from certain), why is that unfortunate? Humans can easily survive a glacial period, and the natural rate such a period comes on is unlikely to cause major societal problems. There will probably be a smaller human population during a glacial period, but I don't see anything unfortunate or problematic about that.

It's not 10 thousand years from now, rather a matter of 1 or 2 centuries

Utter rubbish, with no basis whatsoever.

And of course it's entirely tied to secular variations in orbital parameters, which are well understood and entirely predictable and calculable.

Utter rubbish, with no basis whatsoever.

[Chris Peterson]

You might wish to re-think that assertion. Ice ages last typically about 100,000 years and interglacials about 10,000 years. We're currently 10,500 years into the current interglacial. A helpful discussion and summary of recent climate history may be found at http://www.esd.ornl.gov/projects/qen/nerc130k.html. You'll notice that transitions may be relatively brief and there are often oscillatory swings of considerable amplitude. One may wonder if the Little Ice Age was such a swing and if we may be close to the end of the current interglacial.

Nothing to rethink. While there's obviously a pattern to the timing between generally warm and generally cold periods, there's a huge variability. To suggest that in two hundred years we'll be entering another ice age is unfounded and ridiculous. All you need to do is look at what's gone on the last half million years:



It is quite obvious from this that we could be looking at thousands of more years of relative stability, or it could start changing tomorrow. There's no way to tell. It also suggests that milder warm periods, such as the one we're now in, enter their cooling phase slower- typically over thousands of years. And the cycle looks to be something like 100 ky ± 30 ky, with warm cycles lasting 10 ky ± 10 ky.

The link you provide is interesting, but is talking only about the most recent ice age. Note that the conclusion of that discussion is that our climate is fragile, and that we're risking disaster with our current behavior:

The unstable nature of the Earth's climate history suggests that it may be liable to change suddenly in the future. By putting large quantities of greenhouse gases into the atmosphere, humans are exerting pressure on the climate system which might produce a drastic change without much prior warning. As the geologist W.S. Broecker has said, "Climate is an angry beast, and we are poking it with sticks".

[gpobserver]

Chris Peterson wrote:

"The link you provide is interesting, but is talking only about the most recent ice age. Note that the conclusion of that discussion is that our climate is fragile, and that we're risking disaster with our current behavior:

The unstable nature of the Earth's climate history suggests that it may be liable to change suddenly in the future. By putting large quantities of greenhouse gases into the atmosphere, humans are exerting pressure on the climate system which might produce a drastic change without much prior warning. As the geologist W.S. Broecker has said, "Climate is an angry beast, and we are poking it with sticks".

Yes, I saw that but I was principally interested in the chronology. The evidence suggests to me that solar activity is a far greater perturber of climate than anthropogenic CO2. Note that the Little Ice Age occurred at the same time as the Maunder Minimum. For the past eight years or so, the atmospheric content of CO2 (anthropogenic or otherwise) has increased but world climate has cooled.

The temperature record you presented is notable for the duration and stability of the current interglacial. Only the period about 400k bp is comparable or longer. And the instability during the entire period before the current interglacial is quite marked. Are you familiar with the concept of 1/f noise?
http://books.google.com/books?id=w5ptai ... #PPA106,M1
One sees 1/f noise everywhere in nature. Climate should be no different.

[Chris Peterson]

The evidence suggests to me that solar activity is a far greater perturber of climate than anthropogenic CO2.

Maybe. The key point here is "perturber". That doesn't mean that the temperature shifts are primarily the result of changes in solar output, but that changes in solar output tip the climate into a new metastable state. And the thing that actually causes the big changes in temperature is something else- greenhouse gas concentrations being the primary suspect.

Currently, the solar output is stable. The Sun isn't perturbing anything right now. But by adding greenhouse gases, we are. It is entirely possible, even likely, that our current behavior will do the same thing to the Earth's climate that natural perturbations have produced in the past.

For the past eight years or so, the atmospheric content of CO2 (anthropogenic or otherwise) has increased but world climate has cooled.

Some people like to say that, but where is the evidence of such cooling? I look at the data:



and see no such cooling trend. (This is from NASA's Goddard Institute, and shows average and annual temperatures through 1997, the most recent year that has data available.)

The temperature record you presented is notable for the duration and stability of the current interglacial. Only the period about 400k bp is comparable or longer. And the instability during the entire period before the current interglacial is quite marked. Are you familiar with the concept of 1/f noise?

Thank you for making my point. It is obvious that such a noisy record can't be used to suggest what is going to happen in the next 200 years, with respect to the long term glacial/interglacial cycle.

[gpobserver]

Chris Peterson wrote:

"It is obvious that such a noisy record can't be used to suggest what is going to happen in the next 200 years, with respect to the long term glacial/interglacial cycle."

The assertion that an ice age would begin in the near future was not mine. I agree that current knowledge no more permits prediction of an ice age than an earthquake. The longer a quiet period persists in an earthquake zone, the more one becomes apprehensive about "The Big One".

I request a clarification of what you mean by a "noisy record". One may see either great noisiness of a smoothly varying phenomenon or a very faithful recording of a very erratically varying phenomenon. Many of these climate records are extracted from proxy records such as lake sediment varves, hydrogen or oxygen stable isotopes, tree rings, etc. It is my understanding that these climate records show considerable real short-term variability, not poor recording. Continued substantive discussion requires agreement or clarification of such details.

[Chris Peterson]

I request a clarification of what you mean by a "noisy record". One may see either great noisiness of a smoothly varying phenomenon or a very faithful recording of a very erratically varying phenomenon. Many of these climate records are extracted from proxy records such as lake sediment varves, hydrogen or oxygen stable isotopes, tree rings, etc. It is my understanding that these climate records show considerable real short-term variability, not poor recording. Continued substantive discussion requires agreement or clarification of such details.

I agree that much of the "noise" in the temperature record over the time span in question (~0.5 my) is not true noise, but probably does represent actual short term variability. It is only "noise" in the sense that it confounds the possibility of deducing precisely (that is, within a thousand years or more) where glacial periods begin and end. That determination is further confounded by the large uncertainty on the cycle period itself.

[gpobserver]

Mr. Peterson,

I am reading this webpage: http://muller.lbl.gov/pages/IceAgeBook/ ... html%20old. If you have a chance, please examine it. There are some details it may be worth discussing with regard to climate change and ice ages.

- Roy Tucker