12 degrees = half planet abandoned?

[Eclipse]

This TED talk (remixed) says that if we get to 4 or 5 degrees, natural feedbacks (like the 'methane bomb') could take us to 12.
At that point, this popular Grist writer summarises climate science as predicting half the planet would be uninhabitable.
Is this really what climate science is saying? Could the methane feedbacks take us from 4 or 5 degrees to 12 and then dump our great grandchildren with half the planet being uninhabitable?
www.youtube.com/watch?v=pznsPkJy2x8

Read more: http://bravenewclimate.proboards.com/thread/499/talk-says-degrees-planet-evacuated#ixzz3GYu0JMIb

[Tim the plumber]

Good job that didn't happen in any of the previous warm periods that Earth has been through.

[swansont]

Good job that didn't happen in any of the previous warm periods that Earth has been through.

 

Which you have, of course, documented with some kind of credible evidence you've linked to, showing the previous times humans have lived through a period 12 degrees warmer than present.

[Tim the plumber]

 

Which you have, of course, documented with some kind of credible evidence you've linked to, showing the previous times humans have lived through a period 12 degrees warmer than present.

I didn't say anything about humans.

 

In previous times when the planet was often much hotter than 5 degrees warmer than now there was not a sudden massive shift to such a temperature.

 

Why expect that to happen now?

[swansont]

I didn't say anything about humans.

 

In previous times when the planet was often much hotter than 5 degrees warmer than now there was not a sudden massive shift to such a temperature.

 

Why expect that to happen now?

 

I thought you were talking about the habitability, because absolutely nobody made any claim about the 5 degree rise triggering a further rise under any other conditions but the current situation. So your objection is, as usual, content-free.

[Wild Cobra]

Can anyone show me on a log curve, how we might achive 4 to 5 degrees from methane?

 

CO2 is responsible for about 6 degrees total, using the accepted material of consensus. The linear lines show RE (radiative efficenncy.) Using accepted AR4 numbers, N2O and Ch4 are clearle a lesser gas than CO2. How many ppm of CH4 would we need to get to around 25 W/m^2 of total CH4 forcing?

 

Edited October 23, 2014 by Wild Cobra

[Tim the plumber]

 

I thought you were talking about the habitability, because absolutely nobody made any claim about the 5 degree rise triggering a further rise under any other conditions but the current situation. So your objection is, as usual, content-free.

Eh??

 

Are you saying that there is no real possibility/likelihood of a 12 degree rise?

 

If that is the case why is this being discussed at all? Just scarey hype?

Edited October 23, 2014 by Tim the plumber

[swansont]

Eh??

 

Are you saying that there is no real possibility/likelihood of a 12 degree rise?

 

No, I'm not. I made no claim about the likelihood of a 12 degree rise. Why would you think that?

 

There is a claim that a 5 degree rise will trigger a further rise in temperature. That claim is for the present-day earth. It does not hold for earth under any other conditions, so your objection is moot (in addition to being completely free of supporting documentation)

[Tim the plumber]

 

No, I'm not. I made no claim about the likelihood of a 12 degree rise. Why would you think that?

 

There is a claim that a 5 degree rise will trigger a further rise in temperature. That claim is for the present-day earth. It does not hold for earth under any other conditions, so your objection is moot (in addition to being completely free of supporting documentation)

LOL!!!

 

So the fact that previous periods of much hotter climatic conditions have not resulted in the sudden positive feedback effect adding more heat means nothing???

 

What is so dramatically different today?? Why does the permafrost care that there are humans living some thousands of miles away? How does the methane ice on the sea bed tell?

 

It's the same argument that creationists make when they say that replicating conditions of the early Earth to see what carbon chemistry does has no bearing on the formation of life.

 

You are denying clear evidence.

[Essay]

Most of those endangered carbon deposits were formed after the icy poles developed, which is long after those "previous periods of much hotter climatic conditions" that you are thinking about. That's why it is different this time.

~

[swansont]

LOL!!!

 

So the fact that previous periods of much hotter climatic conditions have not resulted in the sudden positive feedback effect adding more heat means nothing???

 

...

 

You are denying clear evidence.

Which periods are you referring to? You are PROVIDING no evidence, merely naysaying any claim. So how can I be denying anything?

[Tim the plumber]

Which periods are you referring to? You are PROVIDING no evidence, merely naysaying any claim. So how can I be denying anything?

Are you aware that the present climate of the Earth is cool by comparison with the average climate for the Earth over say a billion years?

 

I ask because this seems to be very common knowledge in any group of people who are armchair science TV watchers or better. I would like to know at what level I should pitch the answer.

Most of those endangered carbon deposits were formed after the icy poles developed, which is long after those "previous periods of much hotter climatic conditions" that you are thinking about. That's why it is different this time.

~

OK, that's a reasonable point.

 

But since the endangered deposits are just the edges of the extent of the permafrost I see no undue reason to expect a vast input from the totality of the permafrost zones. It's not all at risk.

Can anyone show me on a log curve, how we might achive 4 to 5 degrees from methane?

 

CO2 is responsible for about 6 degrees total, using the accepted material of consensus. The linear lines show RE (radiative efficenncy.) Using accepted AR4 numbers, N2O and Ch4 are clearle a lesser gas than CO2. How many ppm of CH4 would we need to get to around 25 W/m^2 of total CH4 forcing?

 

Don't hold your breath waiting for a reply.

 

It would take an understanding of what forcing is and what a watt is to make sense of such a graph.

 

I'm surprised that the methane line is so low. Is that as a result of it's direct effect being negligible or that the wavelengths it reflects/emits are already covered by other gasses or just that it's not actually effective?

[Wild Cobra]

Don't hold your breath waiting for a reply.

 

It would take an understanding of what forcing is and what a watt is to make sense of such a graph.

 

I'm surprised that the methane line is so low. Is that as a result of it's direct effect being negligible or that the wavelengths it reflects/emits are already covered by other gasses or just that it's not actually effective?

 

The implication of this graph I made years back is over most peoples heads. It surprises most people methane is so low, because the alarmists keep saying it is a stronger greenhouse gas. To imply such a deception, they have to use made up metrics by the climate community like "radiative efficiency" and "global warming potential." Few people actually understand what these metrics really are, but go "Oh My God!" when they are told the numbers.

 

I was waiting for someone to challenge it, but it appears we have no takers.

 

And... I was not holding my breath, thank God.

 

I like this:

 

4.1.1 To evaluate possible policy options, it is useful to

know the relative radiative effect (and, hence, potential

climate effect) of equal emissions of each of the greenhouse

gases. The concept of relative Global Warming Potentials

(GWP) has been developed to take into account the differing

times that gases remain in the atmosphere.

 

https://www.ipcc.ch/ipccreports/1992%20IPCC%20Supplement/IPCC_1990_and_1992_Assessments/English/ipcc_90_92_assessments_far_full_report.pdf

 

Am I taking that out of context? You decide.

 

The problem is the GWP doesn't account for anything but the 1 ppb addition to current levels calculated from RE (radiative efficiency.) Policy makers, not actually understanding the sciences think it continues to project linearly when in fact, it is primarily a log function. Plus, while RE uses volume, GWP uses mass. Since CH4 has a molar mass of 16.0425 g/mol and CO2 a molar mass of 44.0095 g/mol, this skews the numbers even more for those not completely understanding the facts of science around it. We are now adding 2-3/4 times more CH4 than CO2 for the comparison... Perfectly geared to sway policy makers...

[swansont]

Are you aware that the present climate of the Earth is cool by comparison with the average climate for the Earth over say a billion years?

 

I ask because this seems to be very common knowledge in any group of people who are armchair science TV watchers or better. I would like to know at what level I should pitch the answer.

OK, that's a reasonable point.

 

Your citation-free streak is still intact, I see.

[swansont]

Can anyone show me on a log curve, how we might achive 4 to 5 degrees from methane?

 

CO2 is responsible for about 6 degrees total, using the accepted material of consensus. The linear lines show RE (radiative efficenncy.) Using accepted AR4 numbers, N2O and Ch4 are clearle a lesser gas than CO2. How many ppm of CH4 would we need to get to around 25 W/m^2 of total CH4 forcing?

 

 

What's the source for your graph? Where did 25 W/m^2 come from? Or 4-5 degrees for that matter?

[Tim the plumber]

Your citation-free streak is still intact, I see.

https://www.climate.gov/news-features/climate-qa/whats-hottest-earths-ever-been

 

Even after those first scorching millennia, however, the planet has sometimes been much warmer than it is now. One of the warmest times was during the geologic period known as the Neoproterozoic, between 600 and 800 million years ago. Another “warm age” is a period geologists call the Paleocene-Eocene Thermal Maximum, which occurred about 56 million years ago.

 

Is this actually news to you?

 

What's the source for your graph? Where did 25 W/m^2 come from? Or 4-5 degrees for that matter?

Well I fully understood how to use that graph and why he is talking about a 4-5 degree temperature rise. It's because that's what the OP is talking about.

 

Wild Cobra,

 

Where did the basic data for the effects of these gasses come from and why is it a logarithmic effect?

[swansont]

https://www.climate.gov/news-features/climate-qa/whats-hottest-earths-ever-been

 

I don't see how this supports your claims, which stated that natural feedbacks have never been present in sudden temperature rises. What you've established is that the temperature has been warmer before (~56 mya and 600-800 mya), which is only a small part of your claim.

 

 

Well I fully understood how to use that graph and why he is talking about a 4-5 degree temperature rise. It's because that's what the OP is talking about.

 

 

 

Actually no, the OP (more specifically the video linked in the OP) is NOT talking about methane causing 4-5 degrees of temperature rise. The speaker mentions methane and albedo changes from ice melt as two example of feedbacks present that will contribute to temperatures rising. Very little was quantified in that talk, other than the overall temperature increase.

[Tim the plumber]

 

From http://geology.utah.gov/surveynotes/gladasked/gladice_ages.htm

 

From http://stepwilh.blogspot.co.uk/2010/07/hockey-stick-graph.html

The MGTO was a a period of climatic history occurring from roughly 700-1300 AD. According to the Intergovernmental Panel on Climate Change (IPCC), temperatures during this period (especially in the North Atlantic) were higher than they are today. This period was followed by the LIA from roughly (1560-1830) in which climate temperatures were lower than they are today. Sunspot activity/data has correlated with the LIA which has posed questions as to the validity of greenhouse effects on recent temperature/climate changes.

 

This may be news here but generally all those who have taken any interest in this subject are aware of the fact that the world's climate has bee warmer in the past.

 

When it warmed to levels higher than today's there was no methane bomb. It seems unlikely that today's temperatures will cause such a thing.

[swansont]

North America is not the world, and there are no numbers on the temperature scale. As for the first graph, even though it is not to scale, where is the evidence that no feedbacks were involved?

[Tim the plumber]

North America is not the world, and there are no numbers on the temperature scale. As for the first graph, even though it is not to scale, where is the evidence that no feedbacks were involved?

 

The point is that there have been warmer periods in Earths history without the massive heating of +12 degrees leaving lots of the world uninhabitable.

 

Some of these periods of being warmer than today have been since the last ice age.

 

The permafrost that is vulnerable to melting from similar heating clearly has been laid down since the last time it was warm.

 

I found these graphs very quickly. If the information in them is new to you I must ask why it is that you feel so confident discussing this sort of subject.

Edited October 26, 2014 by Tim the plumber

[Wild Cobra]

 

What's the source for your graph? Where did 25 W/m^2 come from? Or 4-5 degrees for that matter?

 

Good question, I probably should have elaborated better. Since I have time right now this Sunday, I will give probably more than simple elaboration.

 

I used numbers out of the AR4 for changes from 1750 to 2005, and plotted them on a log curve to make the graph. These numbers are found on page 141 of the AR4, Table 2.1.

 

I used this log formula format in excel for each cell:

 

=C$2*(LN(1+$A94)-LN(1+$A$17))

 

Of course, the cells change. For example, column A is for the levels in ppm. Column C is the results for CO2. Cell C2 is my constant for the multiplier for CO2 in this case. In column A, row 17 is set to zero. I used several more columns in this sheet as I have the three CO2 formulas shown in TAR along with their CH4 and N2O formulas, and my log variation for each gas.

 

What I did for example is take the difference between the results for 278 ppm, and 379 ppm. I changed cell C2 until this difference between the 278 and 379 was 1.66, as the AR4 claims 1.66 W/m^2 forcing for the change in CO2 from the 278 to 379 ppm. The value of cell C2 became 5.37287300230489. This isn't exactly the formula used by the IPCC. Here are their formulas:

 

 

The IPCC uses the first of three CO2 formulas with the constant of 5.35. I simply used a version of a log curve so I could get a zero input value.

 

I can replot all this with the different formulas in the graphic. I have them all in the spreadsheet I have pulled up. Plus, I have later found the IPCC assumed value rounded to 1.66 is actually something like 1.655... I don't see too much use in worrying about that small of a change though.

 

I used the same log formulation to plot CH4 and N2O. I used values of CH4 at 0.73 and 1.774 and adjusted the constant to get the 0.48 W/m^2 the AR4 claims. I used 0.27 ppm and 0.319 ppm for N2O adjusting its constant until I had the 0.16 W/m^2 forcing claimed.

 

This gave me the log curves for the three gasses and allows me to approximate the absolute forcing instead of just the flux. CO2 at 379 ppm becomes 31.9 W/m^2. CH4 at 1774 ppb becomes 1.04 W/m^2. N2O at 319 ppb becomes 1.17 W/m^2.

 

Then I plotted for RE (Radiative efficiency.) I took another column with only two values for each gas. CO2 I used 379 and 379.001. CH4 I used 1.774 and 1.775. N2O I used 0.319 and 0.32. I let Excel to plot those slopes, and those are the three strait lines on my graph. If you notice, they are close to the AR4 RE numbers. The AR4 has CO2 at 1.4 x 10^-5, CH4 at 3.7 x 10^-4, and N2O at 3.03 x 10^-3. Table T8.2 is on page 33 of the AR4. Table 2.14 on page 212 also has these numbers.

 

 

It is important to understand that both the RE and GWP numbers use the instantaneous slope from the starting gas value. There is a widespread illusion out there that CH4 is stronger than CO2, because both the radiative efficiency and global warming potential numbers are greater.

 

RE... This is based on adding 1 ppbv to a gas. With CO2 at 379000 ppb, adding 1 ppb is only increassing it by 0.000264%. However, adding 1 ppb to CH4 is increasing it by 0.056%.

 

GWP... This is even worse, because it uses mass changes instead of volume changes. Therefore, it is an effect where equal mass changes at this point are another 2.75 times greater yet than volume changes.

 

These numbers are misleading unless you understand exactly what they mean. I will contend the IPCC does this intentionally to influence the non scientific policy makers.

 

Sorry for being so longwinded at that.

 

I misread the intent of the 4-5 degrees, but off that graph, based the 25 W/m^2 as being about 4-5 degrees. With CO2 at around 30 W/m^2 total forcing, if you assume a 6 degree value for CO2, that means there is about a 1 degree increase per 5 W/m^2 increase. I once found the original paper that supports this. I forget where it is, I probably have it saved. However, Al Gore uses it in his presentations. Here is one of Al Gore's graphs from An Inconvenient Truth I saved in my photobucket:

 

 

As you see, he has a CO2 forcing of around 30 W/m^2 total for CO2 above other forcings that are around 230 W/m^2. He shows this to be close to the 6 degrees I speak of.

 

My question asking how CH4 could cause such warming, along with the graph, was to show it would take a ridiculously large amount of CH4 plotted on a log curve.

 

Now of course, I used a different formula than the AR4 does, which may change the numbers significantly from consensus for CH4. The IPCC uses the one I circled in orange on the graphic I supplied from TAR table 6.2. I suspect the difference between CO2 and CH4 is less if using their formula, but CO2 will still be a stronger gas. CH4 also, will change more and more logarithmic as the CH4 levels exceed N2O levels in magnitudes, rather than being close in level. The formula is as odd as it is to account for CH4/N2O overlap. In my opinion, the close to pure log curve is the better way to plot it, but that's just my opinion. Maybe someday, you can convince me to plot these with the different formulas.

 

OK...

 

Did I answer things to you satisfaction?

 

I'm open to questions.

 

Damn, I hope I caught my spelling and other error…

Wild Cobra,

 

Where did the basic data for the effects of these gasses come from and why is it a logarithmic effect?

 

Just explained it, see above.

 

As for why is it log? The whole climate community agrees it is primarily log. just look at the formulas above from the IPCC TAR.

Edited October 26, 2014 by Wild Cobra

[Strange]

Some of these periods of being warmer than today have been since the last ice age.

Is that the case? I find that slightly surprising. And it appears to be contradicted by this graph:

http://en.wikipedia.org/wiki/Holocene_climatic_optimum#mediaviewer/File:Holocene_Temperature_Variations.png

Edited October 26, 2014 by Strange

[swansont]

 

 

I misread the intent of the 4-5 degrees, but off that graph, based the 25 W/m^2 as being about 4-5 degrees. With CO2 at around 30 W/m^2 total forcing, if you assume a 6 degree value for CO2, that means there is about a 1 degree increase per W/m^2 increase. I once found the original paper that supports this. I forget where it is, I probably have it saved. However, Al Gore uses it in his presentations. Here is one of Al Gore's graphs from An Inconvenient Truth I saved in my photobucket:

 

 

...

 

As you see, he has a CO2 forcing of around 30 W/m^2 total for CO2 above other forcings that are around 230 W/m^2. He shows this to be close to the 6 degrees I speak of.

 

My question asking how CH4 could cause such warming, along with the graph, was to show it would take a ridiculously large amount of CH4 plotted on a log curve.

 

Now of course, I used a different formula than the AR4 does, which may change the numbers significantly from consensus for CH4. The IPCC uses the one I circled in orange on the graphic I supplied from TAR table 6.2. I suspect the difference between CO2 and CH4 is less if using their formula, but CO2 will still be a stronger gas. CH4 also, will change more and more logarithmic as the CH4 levels exceed N2O levels in magnitudes, rather than being close in level. The formula is as odd as it is to account for CH4/N2O overlap. In my opinion, the close to pure log curve is the better way to plot it, but that's just my opinion. Maybe someday, you can convince me to plot these with the different formulas.

 

 

 

I'm having trouble reconciling that with the IPCC forcing, which has CO2 at ~1.7W and CH4 at ~0.5W

http://en.wikipedia.org/wiki/File:Radiative-forcings.svg

 

I suspect this is from using different baselines, i.e. post-industrial-revolution vs. no atmosphere at all, since greenhouse is responsible for ~30 ºC of warming before we worry about recent changes.

 

I also don't follow how 1 W/m^2 gives approximately 1 degree of warming if 30 W/m^2 gives 6 degrees. Did you mean 5 W/m^2? (The Stefan-Boltmann law gives ~5 W for 1 degree at 288K)

 

(I don't find that graph at http://web.ncf.ca/jim/ref/inconvenientTruth/ and considering what I found by Googling Willis Eschenbach — he posts at Watt's Up With That and lacks science credentials — I doubt Gore uses that graph)

These numbers are misleading unless you understand exactly what they mean. I will contend the IPCC does this intentionally to influence the non scientific policy makers.

 

I suspect it's because industrial numbers are often given in terms of mass, and that politicians don't know what a mole is other than being a furry rodent.

[Wild Cobra]

 

 

I'm having trouble reconciling that with the IPCC forcing, which has CO2 at ~1.7W and CH4 at ~0.5W

http://en.wikipedia.org/wiki/File:Radiative-forcings.svg

 

 

Well, when I made that graph, I used the AR4 values. The current values in Wikipedia are probably AR5 values, the lastest assessment report. I've been meaning to update the graph, but sometines I have a hard time finding those round-tuits.

 

Here is a similary graphic from the AR4, I added only the green ovals:

 

 

 

 

 

I suspect this is from using different baselines, i.e. post-industrial-revolution vs. no atmosphere at all, since greenhouse is responsible for ~30 ºC of warming before we worry about recent changes.

 

 

I'm using available matterial blessed by consensus. H2O is the largest greenhouse gas contributer. I will throw a ballpark guess that it contributes to about 24 degrees of the greenhouse effect, CO2 about 6, and other gasses the remaining 3 degrees. That however is based on an approximate 33 degree greenhouse effect, which I have a different viewpoint on. I will probably bring that up spomething, but not now. Not relavant to this discussion.

 

 

I also don't follow how 1 W/m^2 gives approximately 1 degree of warming if 30 W/m^2 gives 6 degrees. Did you mean 5 W/m^2? (The Stefan-Boltmann law gives ~5 W for 1 degree at 288K)

 

 

Correct. Somehow I missed putting the value "5" in as I intended. I will edit if edit time isn't expired when done here.

 

 

(I don't find that graph at http://web.ncf.ca/jim/ref/inconvenientTruth/ and considering what I found by Googling Willis Eschenbach — he posts at Watt's Up With That and lacks science credentials — I doubt Gore uses that graph)

 

Gore used that graph, though now you have me questioning my certainty on it. I have An Inconvienet Truth, and I am watching it now.

 

I suspect I clipped a graph Exchenbach used talking about Gore's material.

 

I don't think I'm wrong. I'm sure Gore used it, but I will verify.

 

 

I suspect it's because industrial numbers are often given in terms of mass, and that politicians don't know what a mole is other than being a furry rodent.

 

You mean mol, right?

 

I will not disagre with you since I'm only guessing myself.

 

 

 

 

Edit add:

This is interesting. I can't find the graphic. I am certain I saw it those years ago. When an Inconvienent Truth first came out, I had a copy of it. It had a scene that the recent version I bought doesn't. I think this chart was a cut scene. The original movie was 100 minutes according to IMDB. The one I recently purchased to replace my first edition copy is only 96 minutes.

 

I would like to show that graphic was there, but I can't. It is possible I was wrong, but I relly don't think so.

 

Help please. Any one have a first edition of the movie?

Edited October 27, 2014 by Wild Cobra

[Tim the plumber]

 

Is that the case? I find that slightly surprising. And it appears to be contradicted by this graph:

http://en.wikipedia.org/wiki/Holocene_climatic_optimum#mediaviewer/File:Holocene_Temperature_Variations.png

That graph has lots of lines on it.

 

The big bold black line is the only one which does not have higher points on it than the present climatic temperatures. The big black line is quoted as being from instrumentation, I don't get how it can be for such a long period.

 

Are the other lines which show a variation wider than today's temperature wrong given that they are proxies from ice cores and the like which I find to be a more direct measure than some sort of data manipulated thing I don't understand and is certainly not explained within the explanation of the graph?

 

Also it is very poor to put a high fidelity part of the graph where we have temperature records from thermometers next to the automatically flattened data from ice core proxies etc. This will automatically make today's fluctuations look far more dramatic.