What is the correct value of Climate Sensitivity?

[-1=e^ipi]

I thought I would try to re-estimate the rate at which the oceans + biosphere uptake CO2. This uptake roughly follows Henry’s law, so the rate of uptake will be proportional to atmospheric CO2 minus Henry’s constant times dissolved CO2 in the ocean. As you increase temperature, Henry’s constant goes down (water can’t hold as much CO2), and the effect of the CO2 temperature feedback is roughly (25 +/- 5) ppm per K (95% confidence interval as obtained from Pleistocene ice core data).

It is also known that the oceans can absorb roughly 85% of emitted CO2 in the long run. The number of gigatones of carbon emitted that correspond to a 1 ppm increase of CO2 can be calculated as follows:

The mass of atmosphere is 5.15 x 10^18 kg (http://en.wikipedia.org/wiki/Atmosphere_of_Earth). Average molar mass is of the atmosphere is 0.78*28 + 0.21*32 + 0.01*40 = 28.96 g/mol. Thus the atmosphere has roughly 1.778 x 10^20 moles. Carbon has a molar mass of 12 g/mol, which suggests that 1 ppm corresponds to 2.13 gigatons.

To estimate the rate of CO2 uptake, I’ll use:

Past Human CO2 emissions: http://cdiac.ornl.gov/ftp/ndp030/global.1751_2008.ems

Past atmospheric CO2 levels: Mauna Loa + Law Dome data

Past global temperatures: Hadcrut4 + the assumption that there was negligible global temperature change from 1751 to 1850.

This gives me data from 1751-2008.

I can calculate annual CO2 uptake by taking the annual CO2 emissions, dividing by 2.13 gigatons per ppm and then subtracting the annual change in CO2. If I assume that CO2 levels were in equilibrium between the atmosphere and the oceans in 1751, then I can integrate annual CO2 uptake, multiply by 0.15/0.85 and add atmospheric CO2 in 1751 to obtain dissolved CO2 in ppm.

I can estimate the rate of CO2 uptake by performing a linear regression of:

Uptake = k*(CO2 – (25 +/- 5)*T – dissolved_CO2) + error

This is a simple exponential decay to equilibrium model (with the CO2-temperature feedback added). Estimating this model (and taking into account the uncertainty in the CO2-temperature feedback) gives k = 0.0211 +/- 0.0016. This suggests that the decay time towards equilibrium is roughly k/(1 + 0.15/0.85) = 40.3 +/- 3.1 years.

This suggests that the rate of CO2 uptake is much faster than I suggested it was earlier in this thread. This result agrees with a paper I skimmed recently which suggested that the decay time of ocean uptake is between 35 and 90 years (I forgot the link ).

Edited April 26, 2015 by -1=e^ipi

[-1=e^ipi]

A bit more on emission scenarios:

I was looking at trends in CH4, N2O, SO2 and minor GHGs. It seems that I might be able to make a reasonable 'business-as-usual' emission scenario by simply assuming that emissions per capita follow an exponential trend and population follows a logistic trend.

If I take the CO2 emission data after 1970 (the year that a major clear-air act amendment passed in the US, so it represents a new 'policy regime'), then an exponential function fits fairly well to real GDP per unit of CO2 emitted (the last post I used a quadratic trend but used data starting in 1950). If both real GDP per unit of CO2 emitted and real GDP per capita follow exponential trends, then this simplifies to emissions per capita following an exponential trend.

A similar assumption (exponential trend in emissions per capita) fits the CH4 and N2O emissions (I can infer emissions by using the 12 year and 114 year decay times for CH4 and N2O as recommended by the EPA, plus take into account the temperature feedback that I can estimate from pleistocene data). The trend in SO2 emissions also fits this assumption (despite the fact that global SO2 emissions have been slowly decreasing since the 70s).

As for trends in minor greenhouse gas emissions such as CFC11, CFC12, CFC113, CCl4, SF6 emissions (which I can infer using empirically accepted decay time values) they follow a roughly exponential trend for emissions per capita starting around 1990. This may be due to the Montreal Protocol being in 1989 and then the amendment to the clear air act for CFCs being in 1990 (so starting in 1990 there is a new 'policy regime' for minor GHGs due to concerns about Ozone depletion).

[-1=e^ipi]

One thing the above 'business as usual' model doesn't take into account is that there is only a limited amount of fossil fuels left. There are ~2795 gigatons of fossil fuel reserves. If all of this were burned all at once, this would correspond to 1312 ppm increase in atmospheric CO2. Although, in the long run 85% of that is absorbed by oceans, so this would correspond to a long term atmospheric CO2 level of (1312 + 400 - 278)*0.15 + 278 = 493 ppm. With a climate sensitivity of say 2.5 C, this would correspond to 2.07 C increase relative to pre-industrial levels. More realistically, it takes a long time for oceans to absorb excess CO2; if we assume that transient uptake is roughly half of emissions, then this means that atmospheric CO2 would peak around 1056 ppm, which would correspond to ~4.8 C increase in temperatures relative to pre-industrial temperatures. Obviously, this doesn't take into account the increased levels of CH4, N2O, nor the CO2-temperature feedback, but I thought I would throw some numbers around.

[-1=e^ipi]

Thought I would post this link of a summary of some of the results of a study by Peter Lang:

https://www.masterresource.org/wind-power/peter-lang-on-australias-windpower-costs-and-small-emissions-gains/

Shows why a high emphasis on wind/solar is problematic, and can even result in an increase in CO2 emissions because it must be supplemented with coal in order to have smooth energy production. Nuclear is a much better option.

[On Guard for Thee]

Hottest first Q ever recorded, least amount of Arctic ice ever recorded, most Antarctic sea ice ever recorded. Snowstorms on one side of Oklahoma, tornados on the other. Apparently the actual weather effects of GW arent abiding by all those tic tac toe games.

[Smallc]

Weather isn't climate, in case you hadn't heard.

[On Guard for Thee]

Weather isn't climate, in case you hadn't heard.

Yeah, thats very true and we have all heard that old saw a million times by now. Do you understand the difference...

[Smallc]

Yeah, thats very true and we have all heard that old saw a million times by now.

You're the one intermingling the issues. I very much believe in AGW, but what you're talking about isn't proof, for the most part.

[On Guard for Thee]

You're the one intermingling the issues. I very much believe in AGW, but what you're talking about isn't proof, for the most part.

Perhaps not proof, but serious evidence.

[Smallc]

Perhaps not proof, but serious evidence.

Ice cover changes can, when measured over time, be evidence, yes. Isolated extreme weather events (thing that has varied over the last decade) are not any kind of evidence.

[On Guard for Thee]

Ice cover changes can, when measured over time, be evidence, yes. Isolated extreme weather events (thing that has varied over the last decade) are not any kind of evidence.

And those ice cover changes are providing very strong evidence. Those changes didnt happen just today.

[TimG]

And those ice cover changes are providing very strong evidence. Those changes didnt happen just today.

They provide evidence for a point that almost no one disputes: that the planet is warming. The trouble is you want to pretend that the simple observation that the planet is warming means we must immediately work to end all fossil fuel use. This is false premise. A warmer world will be a better world in many ways and we have finite resources to spend altruistic ventures like CO2 reduction schemes. There are many more effective uses for those resources. In fact, wasting too many resources on futile CO2 schemes will undermine our ability to adapt and leave us more exposed to any negative effects of climate change. Edited May 11, 2015 by TimG

[On Guard for Thee]

They provide evidence for a point that almost no one disputes: that the planet is warming. The trouble is you want to pretend that the simple observation that the planet is warming means we must immediately work to end all fossil fuel use. This is false premise. A warmer world will be a better world in many ways and we have finite resources to spend altruistic ventures like CO2 reduction schemes. There are many more effective uses for those resources.

Like building a dam to contain a melting glacier...sheesh.

[TimG]

Like building a dam to contain a melting glacier...sheesh.

A dam is well established technology used to store water and an more than adequate replacement for melting glaciers. If you cannot understand that it simply shows you don't know much despite your posturing. Edited May 11, 2015 by TimG

[Smallc]

And those ice cover changes are providing very strong evidence. Those changes didnt happen just today.

Then don't throw in weather reports with that.

[On Guard for Thee]

A dam is well established technology used to store water and an more than adequate replacement for melting glaciers. If you cannot understand that it simply shows how little you understand despite your posturing.

There are a lot more issues involved in losing a glacier than simply building a dam somewhere will address. Plus you are going to have to build a lot of dams in the antarctic and greenland. Better get at it.

[TimG]

There are a lot more issues involved in losing a glacier than simply building a dam somewhere will address. Plus you are going to have to build a lot of dams in the antarctic and greenland. Better get at it.

Your response further illustrates that you have no clue. If you actually understood what you are arguing about you would realize that 'building dams in Antarctica' is a absurd thing to say given the water storage problem being discussed. A red herring is probably the best term. Edited May 11, 2015 by TimG

[On Guard for Thee]

Your response further illustrates that you have no clue. If you actually understood what you are arguing about you would realize that 'building dams in Antarctica' is a absurd thing to say given the water storage problem being discussed.

Just following your lead. You are the one who thinks dams are the way to offset ice sheet melt.

[TimG]

Just following your lead. You are the one who thinks dams are the way to offset ice sheet melt.

Now you are just making crap up. I never said any such thing. If you insist on bring the topic up the why don't you go back a read the relevant posts before filling the board with your delusions.

[On Guard for Thee]

Now you are just making crap up. I never said any such thing. If you insist on bring the topic up the why don't you go back a read the relevant posts before filling the board with your delusions.

I would simply refer you back to #439.

[TimG]

I would simply refer you back to #439.

I said nothing about 'ice sheets'. More importantly, context matters since you keep bringing up a prior discussion so the use of the words in that discussion is what matters. If you insist on bringing up that discussion you should go back a read what was said instead of making up random irrelevant crap. Edited May 11, 2015 by TimG

[On Guard for Thee]

I said nothing about 'ice sheets'. More importantly, context matters since you keep bringing up a prior discussion so the use of the words in that discussion is what matters. If you insist on bringing up that discussion you should go back a read what was said instead of making up random irrelevant crap.

Arent glaciers basically ice sheets...But more importantly how do you propose your dam will succeed in feeding the biodiversity currently provided for by the cyclical seasonal flow from glaciers once they are gone. And, what effect do you think their loss will have on already warming climate. I think scientists refer to it as a tipping point.

Edited May 11, 2015 by On Guard for Thee

[TimG]

Arent glaciers basically ice sheets...But more importantly how do you propose your dam will succeed in feeding the biodiversity currently provided for by the cyclical seasonal flow from glaciers once they are gone.

It is not a relevant concern. The issue being discussed is how some human settlements relay on the water storage capabilities of glaciers to even out water flow over the year. Dams already provide this capability today and would easily replace that function of glaciers.

This is a good example of the bankrupt economics of climate alarmists. You seem to think that the possibility of 'unknown' problems is enough to justify spending infinite resources to prevent change. The real world does not work like this and any policy based on this premise will fail miserably. Instead, we need to prioritize by focusing of real problems and finding adaptations that will allow society to work with the changing climate.

Edited May 11, 2015 by TimG

[On Guard for Thee]

It is not a relevant concern. The issue being discussed is how some human settlements relay on the water storage capabilities of glaciers to even out water flow over the year. Dams already provide this capability today and would easily replace that function of glaciers.

This is a good example of the bankrupt economics of climate alarmists. You seem to think that the possibility of 'unknown' problems is enough to justify spending infinite resources to prevent change. The real world does not work like this and any policy based on this premise will fail miserably. Instead, we need to prioritize by focusing of real problems and finding adaptations that will allow society to work with the changing climate.

The biodiversity I speak of is not, Im afraid, up to you to decide. And it is certainly not unknown. You are allowed your opinion of course. And just to put it in simple terms, how would air flowing over the big lake behind your dam not be affected differently than flowing over many square miles of ice. Do you not understand the domino effect of that...

[TimG]

The biodiversity I speak of is not, Im afraid, up to you to decide. And it is certainly not unknown.

Bio-diversity is a meaningless catch all used by environmentalists to avoid having a meaningful conversation about the trade offs. What matters are concrete evidence that the new collection of fauna and flora is sufficient for our needs. The simple fact that there may be fewer species is not evidence of a problem. That is why I say it is an unknown hypothetical. Which brings us back to the only real problem that anyone has identified: the loss of water storage capabilities and dams are more than sufficient to address that real problems. Edited May 11, 2015 by TimG