Official Global Warming thread (merged)

[TennTradition]

I just thought somebody might have done an energy balance on the Earth as a black body that has risen 1C they would know the extra radiance it is giving off, how much escapes into space should be known, and is theoretical matching actual in terms of energy and mass balance? I'm don't mean counting all the "feedbacks" as you call them. I would have thought someone had already done those calculations. I've been trying to do an internet search and can't find anything but I'll keep trying.

At a fundamental level that is what the climate models are.

 

[Sandvol]

At a fundamental level that is what the climate models are.

But don't most of the models presume some type of feedback or forcing?

 

[TennTradition]

But don't most of the models presume some type of feedback or forcing?

There is feedback that leads to Clare sensitivity and that is included in that thermodynamic calculation.
Posted via VolNation Mobile

 

[508mikey]

science fiction --- global warming

 

[Sandvol]

There is feedback that leads to Clare sensitivity and that is included in that thermodynamic calculation.
Posted via VolNation Mobile

But, what I'm asking has anybody done calculations that include no feedbacks, i.e. feedbacks don't exist, only the expected change in temperature due to CO2? The reason I'm asking is aren't all the climate models trying to find what the amplifications are due to feedbacks- i.e. determine climate sensitivities? And that the alarmists believe the climate is very sensitive to feedbacks and the skeptics believe the climate is mostly insensitive to feedbacks. Is that not correct? And, that is what the models are for? I just wanted to know what the expected rise is due to CO2 and CO2 alone.

P.S.-The reason I'm asking this is Bart mentioned in one of his blurbs that water was only amplifying-a positive feedback-and I wanted to know what the warming would be without any feedbacks (i.e. taking all the other factors out. I just wondered that someone must have done those theoretical calculations.

 

[Sandvol]

In other words you go back 250 years, shoot an increase of about 120PPM of CO2 into the atmosphere, wait for the temperature rise, no other factors, what should it be?

 

[TennTradition]

I think that there are very likely model runs that dampen the feedbacks and therefore arrive at the result you are wanting. I don't know what those results are. I'll try to remember to check my notebook tomorrow. I may have already performed a very crude version of that energy balance.

 

[BartW]

But, what I'm asking has anybody done calculations that include no feedbacks, i.e. feedbacks don't exist, only the expected change in temperature due to CO2? The reason I'm asking is aren't all the climate models trying to find what the amplifications are due to feedbacks- i.e. determine climate sensitivities? And that the alarmists believe the climate is very sensitive to feedbacks and the skeptics believe the climate is mostly insensitive to feedbacks. Is that not correct? And, that is what the models are for? I just wanted to know what the expected rise is due to CO2 and CO2 alone.

P.S.-The reason I'm asking this is Bart mentioned in one of his blurbs that water was only amplifying-a positive feedback-and I wanted to know what the warming would be without any feedbacks (i.e. taking all the other factors out. I just wondered that someone must have done those theoretical calculations.

Off the top of my head I think I've seen values of 1-1.5 degrees for warming due to doubling CO2 alone (280 ppm to 560 ppm). According to AR4 and everything else a quick google brings up the consensus appears to be 1.2 degrees. There's a spread in the modeled climate sensitivities to feedbacks but I believe most models call for an additional 2-3 degrees warming.

Here's an interesting related figure:

How sensitive is our climate?

 

[Obsessed]

Interesting question. My gut response would be no since 9.0+ earthquakes happen pretty regularly. I looked it up and the Kobe quake supposedly shifted Earth's axis 6.5 inches (I wonder how they measure that?). To me that seems pretty insignificant compared to the tilt of our axis (23.5 degrees = 1000+ miles).

Thanks Bart. I knew it more than likely it had no direct correlation to what you mad scientist are discussing, but I was curious if such a thing may change atmospheric pressures or certainties (sp)

 

[TennTradition]

That's a good link, Bart. That seems to address it.

 

[Sandvol]

I found something here in Economist magazine of all places:

Carbon dioxide itself absorbs infra-red at a consistent rate. For each doubling of CO₂ levels you get roughly 1°C of warming. A rise in concentrations from preindustrial levels of 280 parts per million (ppm) to 560ppm would thus warm the Earth by 1°C. If that were all there was to worry about, there would, as it were, be nothing to worry about. A 1°C rise could be shrugged off. But things are not that simple, for two reasons. One is that rising CO₂ levels directly influence phenomena such as the amount of water vapour (also a greenhouse gas) and clouds that amplify or diminish the temperature rise. This affects equilibrium sensitivity directly, meaning doubling carbon concentrations would produce more than a 1°C rise in temperature. The second is that other things, such as adding soot and other aerosols to the atmosphere, add to or subtract from the effect of CO₂. All serious climate scientists agree on these two lines of reasoning. But they disagree on the size of the change that is predicted.

 

[Sandvol]

Off the top of my head I think I've seen values of 1-1.5 degrees for warming due to doubling CO2 alone (280 ppm to 560 ppm). According to AR4 and everything else a quick google brings up the consensus appears to be 1.2 degrees. There's a spread in the modeled climate sensitivities to feedbacks but I believe most models call for an additional 2-3 degrees warming.

Here's an interesting related figure:

How sensitive is our climate?

That is where the rub is isn't it? Most of the climate models that IPCC use predict a positive feedback and therefore a much higher rise than just what is predicted by CO2 rise. Isn't that correct? Also, it seems the two biggest areas of contention that the IPCC models focus on are clouds and water vapor. Those are the two biggest areas of positive feedback according to the IPCC. Is that correct?

 

[Sandvol]

Essentially we are getting a 2ppm rise in CO2 every year right now. So we'd expect to reach the 560 mark in about 80 years but it would only be about a 1 or 1.2C rise. Nothing to really worry about but the IPCC scientists are saying the feedback would cause an additional 2-3 degrees and I think TT's guy up there is calling for something like 5C additional. Is that correct?

 

[BartW]

I found something here in Economist magazine of all places:

Carbon dioxide itself absorbs infra-red at a consistent rate. For each doubling of CO₂ levels you get roughly 1°C of warming. A rise in concentrations from preindustrial levels of 280 parts per million (ppm) to 560ppm would thus warm the Earth by 1°C. If that were all there was to worry about, there would, as it were, be nothing to worry about. A 1°C rise could be shrugged off. But things are not that simple, for two reasons. One is that rising CO₂ levels directly influence phenomena such as the amount of water vapour (also a greenhouse gas) and clouds that amplify or diminish the temperature rise. This affects equilibrium sensitivity directly, meaning doubling carbon concentrations would produce more than a 1°C rise in temperature. The second is that other things, such as adding soot and other aerosols to the atmosphere, add to or subtract from the effect of CO₂. All serious climate scientists agree on these two lines of reasoning. But they disagree on the size of the change that is predicted.

That is where the rub is isn't it? Most of the climate models that IPCC use predict a positive feedback and therefore a much higher rise than just what is predicted by CO2 rise. Isn't that correct? Also, it seems the two biggest areas of contention that the IPCC models focus on are clouds and water vapor. Those are the two biggest areas of positive feedback according to the IPCC. Is that correct?

Here are the contributions of the different radiative forcings, relative to pre-industrial times:

I think clouds are primarily a negative feedback since they increase albedo (as shown above). It would be silly to assume no feedbacks since temperature increase shifts equilibria toward the gaseous phase. But in general you are correct in saying the amount of feedback is one of the biggest areas of contention. It’s very much a *hot* topic in climate research. From the climate sensitivity link in my last post:

The IPCC Fourth Assessment Report summarized climate sensitivity as "likely to be in the range 2 to 4.5°C with a best estimate of about 3°C, and is very unlikely to be less than 1.5°C. Values substantially higher than 4.5°C cannot be excluded, but agreement of models with observations is not as good for those values."

Individual studies have put climate sensitivity from a doubling of CO2 at anywhere between 0.5°C and 10°C; however, as a consequence of increasingly better data, it appears that the extreme higher and lower values are very unlikely. In fact, as climate science has developed and advanced over time , estimates have converged around 3°C. A summary of recent climate sensitivity studies can be found here.

A study led by Stefan Rahmstorf concluded "many vastly improved models have been developed by a number of climate research centers around the world. Current state-of-the-art climate models span a range of 2.6–4.1°C, most clustering around 3°C" (Rahmstorf 2008). Several studies have put the lower bound of climate sensitivity at about 1.5°C,on the other hand, several others have found that a sensitivity higher than 4.5°C can't be ruled out.

A 2008 study led by James Hansen found that climate sensitivity to "fast feedback processes" is 3°C, but when accounting for longer-term feedbacks (such as ice sheet disintegration, vegetation migration, and greenhouse gas release from soils, tundra or ocean), if atmospheric CO2 remains at the doubled level, the sensitivity increases to 6°C based on paleoclimatic (historical climate) data.

Essentially we are getting a 2ppm rise in CO2 every year right now. So we'd expect to reach the 560 mark in about 80 years but it would only be about a 1 or 1.2C rise. Nothing to really worry about but the IPCC scientists are saying the feedback would cause an additional 2-3 degrees and I think TT's guy up there is calling for something like 5C additional. Is that correct?

How did you get 2 ppm/year? I’m not sure what the current rate is but you can’t extrapolate a linear trend since greenhouse gases are increasing exponentially (see post 2070). That's why climate sensitivity is expressed in terms of doubling CO2. Here's the IPCC projected CO2 levels for various scenarios:

Soo... not trying to come off as alarmist, but IMO it seems unlikely we'll be able to keep the temperature increase under 2 degrees (which is roughly the goal and best case scenario -see figure in previous post)

 

[BigOrangeTrain]

So if global warming is real then what's the solution?

 

[BartW]

So if global warming is real then what's the solution?

That's the million (trillion? :/) dollar question. It's going to take a concerted global effort to mitigate the damage by decreasing emissions. And we're just going to have to adapt to a warmer world. People have suggested climate geoengineering i.e. manually sequestering CO2 but it doesn't sound feasible to me. Got any ideas?

We're not facing the apocalypse (especially here in the good ole US of A), but we'll continue to see increasing stress on global food and drinking water. And eventually the loss of low-lying coastal areas where a good chunk of the global population lives. These are by no means the only effects (AR5 will focus on the socio-economic aspects of AGW), but they are the ones I'm personally most worried about. Good luck Netherlands...

 

[508mikey]

So if global warming is real then what's the solution?

fire Al Roker for starters

 

[Sandvol]

Here are the contributions of the different radiative forcings, relative to pre-industrial times:

I think clouds are primarily a negative feedback since they increase albedo (as shown above). It would be silly to assume no feedbacks since temperature increase shifts equilibria toward the gaseous phase. But in general you are correct in saying the amount of feedback is one of the biggest areas of contention. It’s very much a *hot* topic in climate research. From the climate sensitivity link in my last post:

The IPCC Fourth Assessment Report summarized climate sensitivity as "likely to be in the range 2 to 4.5°C with a best estimate of about 3°C, and is very unlikely to be less than 1.5°C. Values substantially higher than 4.5°C cannot be excluded, but agreement of models with observations is not as good for those values."

Individual studies have put climate sensitivity from a doubling of CO2 at anywhere between 0.5°C and 10°C; however, as a consequence of increasingly better data, it appears that the extreme higher and lower values are very unlikely. In fact, as climate science has developed and advanced over time , estimates have converged around 3°C. A summary of recent climate sensitivity studies can be found here.

A study led by Stefan Rahmstorf concluded "many vastly improved models have been developed by a number of climate research centers around the world. Current state-of-the-art climate models span a range of 2.6–4.1°C, most clustering around 3°C" (Rahmstorf 2008). Several studies have put the lower bound of climate sensitivity at about 1.5°C,on the other hand, several others have found that a sensitivity higher than 4.5°C can't be ruled out.

A 2008 study led by James Hansen found that climate sensitivity to "fast feedback processes" is 3°C, but when accounting for longer-term feedbacks (such as ice sheet disintegration, vegetation migration, and greenhouse gas release from soils, tundra or ocean), if atmospheric CO2 remains at the doubled level, the sensitivity increases to 6°C based on paleoclimatic (historical climate) data.



How did you get 2 ppm/year? I’m not sure what the current rate is but you can’t extrapolate a linear trend since greenhouse gases are increasing exponentially (see post 2070). That's why climate sensitivity is expressed in terms of doubling CO2. Here's the IPCC projected CO2 levels for various scenarios:

Soo... not trying to come off as alarmist, but IMO it seems unlikely we'll be able to keep the temperature increase under 2 degrees (which is roughly the goal and best case scenario -see figure in previous post)

I got 2ppm per year from 2008 it was about 390PPM and here in 2014 it is 400PPM. Currently that is about 2ppm per year more or less.

 

[Sandvol]

Here are the contributions of the different radiative forcings, relative to pre-industrial times:

I think clouds are primarily a negative feedback since they increase albedo (as shown above). It would be silly to assume no feedbacks since temperature increase shifts equilibria toward the gaseous phase. But in general you are correct in saying the amount of feedback is one of the biggest areas of contention. It’s very much a *hot* topic in climate research. From the climate sensitivity link in my last post:

The IPCC Fourth Assessment Report summarized climate sensitivity as "likely to be in the range 2 to 4.5°C with a best estimate of about 3°C, and is very unlikely to be less than 1.5°C. Values substantially higher than 4.5°C cannot be excluded, but agreement of models with observations is not as good for those values."

Individual studies have put climate sensitivity from a doubling of CO2 at anywhere between 0.5°C and 10°C; however, as a consequence of increasingly better data, it appears that the extreme higher and lower values are very unlikely. In fact, as climate science has developed and advanced over time , estimates have converged around 3°C. A summary of recent climate sensitivity studies can be found here.

A study led by Stefan Rahmstorf concluded "many vastly improved models have been developed by a number of climate research centers around the world. Current state-of-the-art climate models span a range of 2.6–4.1°C, most clustering around 3°C" (Rahmstorf 2008). Several studies have put the lower bound of climate sensitivity at about 1.5°C,on the other hand, several others have found that a sensitivity higher than 4.5°C can't be ruled out.

A 2008 study led by James Hansen found that climate sensitivity to "fast feedback processes" is 3°C, but when accounting for longer-term feedbacks (such as ice sheet disintegration, vegetation migration, and greenhouse gas release from soils, tundra or ocean), if atmospheric CO2 remains at the doubled level, the sensitivity increases to 6°C based on paleoclimatic (historical climate) data.



How did you get 2 ppm/year? I’m not sure what the current rate is but you can’t extrapolate a linear trend since greenhouse gases are increasing exponentially (see post 2070). That's why climate sensitivity is expressed in terms of doubling CO2. Here's the IPCC projected CO2 levels for various scenarios:

Soo... not trying to come off as alarmist, but IMO it seems unlikely we'll be able to keep the temperature increase under 2 degrees (which is roughly the goal and best case scenario -see figure in previous post)

But, you are quoting models the IPCC are using. They are using roughly 15-20 models right? And, don't most of those models presume high positive feedback? And, don't most of the models they use presume clouds are a positive feedback?

 

[Sandvol]

In fact, as climate science has developed and advanced over time , estimates have converged around 3°C.

But, one of their problems is that is not what we're seeing. Right?

 

[BartW]

I got 2ppm per year from 2008 it was about 390PPM and here in 2014 it is 400PPM. Currently that is about 2ppm per year more or less.

I found a table of CO2 annual averages here. It does look to be around 2 ppm/year presently. If you follow the link to Accelerating Rise of CO2 you’ll see a table of decadal rates, showing how the rates are increasing. So we can't extrapolate linearly. If we continue “business as usual” the IPCC finds that CO2 will hit 850-950 ppm by 2100.

But, you are quoting models the IPCC are using. They are using roughly 15-20 models right? And, don't most of those models presume high positive feedback? And, don't most of the models they use presume clouds are a positive feedback?

The IPCC reviews all the models in the scientific literature. You’ll have to look at the papers individually to see what kind of feedbacks they’re using. Some predict high feedback and some predict low. From the quote above, models have found climate sensitivity ranging from 0.5 to 10 degrees C per doubling CO2, with most results (especially the most recent state-of-the-art models) clustering around 3 C. Clouds are both a positive and negative feedback: positive because they consist mostly of water vapor, a greenhouse gas, and negative because they increase Earth’s albedo. These wikis might be of interest:

Climate Change Feedback
Cloud Feedback

But, one of their problems is that is not what we're seeing. Right?

So far we’ve seen over 1 C increase in global temperature from a 40% increase in CO2. Most models predict 3 C from a 100% increase in CO2. So that’s par for the course.

 

[Sandvol]

This is Singer's chart that you pooh poohed a few pages back. This is compared to the CMIP-5 model used in AR5. This is mid-troposphere data from UAH. These temperatures tend to indicate climate is less sensitive than the CMIP-5 model.

 

[Sandvol]

I found a table of CO2 annual averages here. It does look to be around 2 ppm/year presently. If you follow the link to Accelerating Rise of CO2 you’ll see a table of decadal rates, showing how the rates are increasing. So we can't extrapolate linearly. If we continue “business as usual” the IPCC finds that CO2 will hit 850-950 ppm by 2100.



The IPCC reviews all the models in the scientific literature. You’ll have to look at the papers individually to see what kind of feedbacks they’re using. Some predict high feedback and some predict low. From the quote above, models have found climate sensitivity ranging from 0.5 to 10 degrees C per doubling CO2, with most results (especially the most recent state-of-the-art models) clustering around 3 C. Clouds are both a positive and negative feedback: positive because they consist mostly of water vapor, a greenhouse gas, and negative because they increase Earth’s albedo. These wikis might be of interest:

Climate Change Feedback
Cloud Feedback



So far we’ve seen over 1 C increase in global temperature from a 40% increase in CO2. Most models predict 3 C from a 100% increase in CO2. So that’s par for the course.

Also, we've seen a 43% rise in CO2 and only about a 30%(the .7-.9C from IPCC-using HADCRUT and GISS) rise in temperature. If you extrapolate you'd only expect about a 2C rise and this indicates the climate is in the less sensitive lower area of the AR5 CMIP-5 model. Also, the CMIP-5 model assumes clouds are a positive feedback.

 

[BartW]

This is Singer's chart that you pooh poohed a few pages back. This is compared to the CMIP-5 model used in AR5. This is mid-troposphere data from UAH. These temperatures tend to indicate climate is less sensitive than the CMIP-5 model.

You'll have to give me a post #, this thread picked up steam and it's not in the Singer paper. Anyhow, I poopood UAH because they're the outlier. First skeptics pointed to UAH and argued "troposphere is cooling", then errors in UAH's analysis were corrected and the argument became "troposphere is not warming enough", and now even that's been reduced to "tropical upper troposphere is not warming enough". Everywhere else all data are consistent with the models.

Another thing is the tropospheric hotspot is not a signature of AGW - the troposphere should warm the same proportionately to the surface regardless of the mechanism. It's based on the moist adiabatic lapse rate and it is observed presently on shorter (e.g. seasonal) scales. Thus, the discrepancy between data are model here are likely due to the data. It's worth noting that, while both natural and GHG warming predict a tropospheric hotspot, natural warming predicts stratospheric warming while GHG warming predicts stratospheric cooling. Guess what we observe?

Also, we've seen a 43% rise in CO2 and only about a 30%(the .7-.9C from IPCC-using HADCRUT and GISS) rise in temperature. If you extrapolate you'd only expect about a 2C rise and this indicates the climate is in the less sensitive lower area of the AR5 CMIP-5 model. Also, the CMIP-5 model assumes clouds are a positive feedback.

If you want to get precise, we've had a 37% increase in CO2 (290 - 398 ppm) and 0.85 C increase since 1880 per GISS. If temperature and CO2 increased together that would yield a sensitivity of 2.3 C. But as I've stated, temperature is now following CO2 unlike in the past when CO2 followed temperature. In the past %CO2 was strictly a feedback from natural forcings, now it's driving the climate. Temperature will catch up. From the article in post 1884,

"The last time the concentration of Earth's main greenhouse gas reached this mark, horses and camels lived in the high Arctic. Seas were at least 30 feet higher—at a level that today would inundate major cities around the world.

The planet was about 2 to 3 degrees Celsius (3.6 to 5.4 degrees Fahrenheit) warmer. But the Earth then was in the final stage of a prolonged greenhouse epoch, and CO2 concentrations were on their way down. This time, 400 ppm is a milepost on a far more rapid uphill climb toward an uncertain climate future."

 

[Sandvol]

You'll have to give me a post #, this thread picked up steam and it's not in the Singer paper. Anyhow, I poopood UAH because they're the outlier. First skeptics pointed to UAH and argued "troposphere is cooling", then errors in UAH's analysis were corrected and the argument became "troposphere is not warming enough", and now even that's been reduced to "tropical upper troposphere is not warming enough". Everywhere else all data are consistent with the models.

Another thing is the tropospheric hotspot is not a signature of AGW - the troposphere should warm the same proportionately to the surface regardless of the mechanism. It's based on the moist adiabatic lapse rate and it is observed presently on shorter (e.g. seasonal) scales. Thus, the discrepancy between data are model here are likely due to the data. It's worth noting that, while both natural and GHG warming predict a tropospheric hotspot, natural warming predicts stratospheric warming while GHG warming predicts stratospheric cooling. Guess what we observe?



If you want to get precise, we've had a 37% increase in CO2 (290 - 398 ppm) and 0.85 C increase since 1880 per GISS. If temperature and CO2 increased together that would yield a sensitivity of 2.3 C. But as I've stated, temperature is now following CO2 unlike in the past when CO2 followed temperature. In the past %CO2 was strictly a feedback from natural forcings, now it's driving the climate. Temperature will catch up. From the article in post 1884,

"The last time the concentration of Earth's main greenhouse gas reached this mark, horses and camels lived in the high Arctic. Seas were at least 30 feet higher—at a level that today would inundate major cities around the world.

The planet was about 2 to 3 degrees Celsius (3.6 to 5.4 degrees Fahrenheit) warmer. But the Earth then was in the final stage of a prolonged greenhouse epoch, and CO2 concentrations were on their way down. This time, 400 ppm is a milepost on a far more rapid uphill climb toward an uncertain climate future."

It looks to me like temperature and CO2 are diverging. CO2 is continuing up and temperature isn't. And, I used 400/280. It just recently crossed 400. That would put it at 43%. And, to me 2C is something we can easily live with. Some of the charts in AR5 indicate we won't even get to 2C. Also, by all indications nature gets rid of half the CO2 that is produced no matter how much is produced. Also, you are proving my point. Camels once lived in the Arctic. The climate has always changed and we can't really do a whole lot about it.