Merged Global Warming Discussion II: Heated Conversation

[aleCcowaN]

Clearly this is utter nonsense. Notable how quick people are willing to accept nonsense when it suits their own biases, even when they claim to be waving the flag of scientific credibility.

So much for "pointed perspectives", huh.

Nope. Clearly there are a set of scenarios that can achieve that.

No one of them is much probable, not even one millionth, me thinks.

Some scenarios that are somewhat probable have shown those results in old, limited modelling. The same scenarios set lower levels of warming with contemporary modelling.

Besides, we are not going to behave as those scenarios analyse, just because all this is to promote such avoidance.

We as a whole are not going to behave like any of those scenarios, with your contribution or in spite of you. What you may do or not belong to other less extreme scenarios.

 

[Trakar]

Some little changes:

-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*

I would characterize your commentary to more generally be disagreements with what I have said. If you would like clarifications of what I have stated, I would be happy to provide a more detailed exploration of these understandings, otherwise I really have no interest in arguing or debating any of these issues with you.

 

[aleCcowaN]

I would characterize your commentary to more generally be disagreements with what I have said. If you would like clarifications of what I have stated, I would be happy to provide a more detailed exploration of these understandings, otherwise I really have no interest in arguing or debating any of these issues with you.

I agree about such disagreement. And thank you for replying offering clarifications. An attitude to be emulated.

About clarifications, just one, if by saying «we are looking at a tripling (at least) of pre-industrial CO2 ratios (~750-1000ppm), and conditions that have not been seen since mammals have been the dominant major forms of life on this planet.» you were implying in any way or measure that our planet is going to show that moment or a few decades after that moment the climate it experienced during such ancient eras.

 

[CoolSceptic]

Nope. Clearly there are a set of scenarios that can clearly achieve that.

No one of them is much probable, not even one millionth, me thinks.

The cartoon says "where we will be in 86 years". Not "one-in-a-million chance of where we will be". Those two statements are not the same thing, and anyone who wants to retain a shred of scientific credibility should be rather critical of that cartoon, not promoting it as some kind of valuable perspective.

Incidentally, the million-to-one quantification is also meaningless, as is your bizarre belief that such a SWAG has any connection to reality. Just to be clear: you have absolutely no idea what probability of 4.5C rise by 2100 might be, whether we cut emissions or not, and either would be indistinguishable from zero with our present understanding. Although those who do not understand that models are not reality, and samples are not populations, may not appreciate why.

 

[Trakar]

Just to clarify your "pointed perspective"

4.5 deg C in the next 86 years, over "modern times" (by which they mean the temperature 100-150 years ago I guess) which is the claim of the cartoon.

We have had around 0.8-0.9 deg C warming since the reference point - but lets be generous and round it up to 1 deg C.

To reach +4.5C in 86 years, that means increasing at a rate of 0.4 deg C per decade, every decade.

Given the peak decadal rate over the last century peaked out at around 0.2 deg C / decade, and we are now below 0.1 deg C / decade by many measures, does anyone who actually claims to adhere to science believe we are going to see 0.4 deg C per decade, EVERY decade, for the next 86 years?

Clearly this is utter nonsense. Notable how quick people are willing to accept nonsense when it suits their own biases, even when they claim to be waving the flag of scientific credibility.

So much for "pointed perspectives", huh.

Please provide any compelling evidences that you are aware of which supports that the climate change issues discussed by MacDoc rely upon, or even imply that, a smooth even increase of temperatures over the next century are called for, or likely, given past or current climate change understandings. Lacking this, your argument is what is colloquially known as a "straw man."

 

[aleCcowaN]

The cartoon says "where we will be in 86 years".

Exactly. It's a cartoon. If you found it to be low quality there's no reason to reply slipping into an even lower quality. You may not understand that certain scenarios say that a 4.5% yearly rise of CO2 emissions will continue the rest of the century because of a unquenchable human avidity for energy and rabbit-like reproduction, meaning yearly emissions in 2090 that match in one year 25% of all the CO2 our atmosphere contains today.

About scenarios you're so sceptic. Simply 10,000 ppmv of CO2 will achieve more than 4°C, and in just a few weeks. From where are going to come those teratons of carbon in a few weeks. I don't know. Frisk me! I don't have them with me. Maybe a few of those old 50 Megaton H-bombs unused can be deployed in a big lump of methane clathrates. That would probably do the trick.

A scenario is just that: a scenario, a "what if ...?".

And for what I know or ignore, it's not precisely you the right person to fathom it.

 

[lomiller]

Just to clarify your "pointed perspective"

4.5 deg C in the next 86 years, over "modern times" (by which they mean the temperature 100-150 years ago I guess) which is the claim of the cartoon.

We have had around 0.8-0.9 deg C warming since the reference point - but lets be generous and round it up to 1 deg C.

To reach +4.5C in 86 years, that means increasing at a rate of 0.4 deg C per decade, every decade.

Given the peak decadal rate over the last century peaked out at around 0.2 deg C / decade, and we are now below 0.1 deg C / decade by many measures, does anyone who actually claims to adhere to science believe we are going to see 0.4 deg C per decade, EVERY decade, for the next 86 years?

Clearly this is utter nonsense. Notable how quick people are willing to accept nonsense when it suits their own biases, even when they claim to be waving the flag of scientific credibility.

So much for "pointed perspectives", huh.

IPCC scenario A2 (relatively slow action dealing with CO2 emissions and population growth) yields a like range of temperature increase of 2.0 - 5.4 Deg C with a best estimate increase of 3.4 Deg C by 2100 relative to early 1990's and a little under 4.5 relative to 1900.

http://www.ipcc.ch/publications_and_data/ar4/wg1/en/spmsspm-projections-of.html

The A2 scenario does result in higher temperatures than most of all the ones the IPCC uses, but it's essentially the "what happens if we do nothing about global warming" scenario so it may be appropriate to use in this case.

TBH I'm pessimistic about us actually doing anything about climate change. I think the only thing that may save us from this emissions scenario is simply running out of easily available fossil fuels.

 

[macdoc]

4.5 deg C in the next 86 years, over "modern times" (by which they mean the temperature 100-150 years ago I guess) which is the claim of the cartoon.

We have had around 0.8-0.9 deg C warming since the reference point - but lets be generous and round it up to 1 deg C.

To reach +4.5C in 86 years, that means increasing at a rate of 0.4 deg C per decade, every decade.

Given the peak decadal rate over the last century peaked out at around 0.2 deg C / decade, and we are now below 0.1 deg C / decade by many measures, does anyone who actually claims to adhere to science believe we are going to see 0.4 deg C per decade, EVERY decade, for the next 86 years?

Clearly this is utter nonsense. Notable how quick people are willing to accept nonsense when it suits their own biases, even when they claim to be waving the flag of scientific credibility.

So much for "pointed perspectives", huh.

So much for your

a) sense of humour

b) climate knowledge.

There are numerous routes to 4.5C in 86 years but it starts with this.

Does CO2 trap IR.??We'll take a simple yes or no.

You use the usual denier trick of extending your "analysis backward to the start of the century to reduce the decadal climb.

Given the peak decadal rate over the last century peaked out at around 0.2 deg C /

to use the slow gain of the first 50 years to dilute the gain in the last few decades.

Right now China and Malayasia/India are putting out enough SO2 to blunt the CO2 gain.
Clean that SO2 up as happened in NA/Europe as Acid Rain campaigns reduced global dimming.

A new paper has shown the climate sensitivity to be on the high side - a doubling producing 3 degrees and we are heading beyond that by end of century with BAU. and that sensitivity matches better with observation.

Equilibrium climate sensitivity refers to the ultimate change in global mean temperature in response to a change in external forcing. Despite decades of research attempting to narrow uncertainties, equilibrium climate sensitivity estimates from climate models still span roughly 1.5 to 5 degrees Celsius for a doubling of atmospheric carbon dioxide concentration, precluding accurate projections of future climate. The spread arises largely from differences in the feedback from low clouds, for reasons not yet understood. Here we show that differences in the simulated strength of convective mixing between the lower and middle tropical troposphere explain about half of the variance in climate sensitivity estimated by 43 climate models.

The apparent mechanism is that such mixing dehydrates the low-cloud layer at a rate that increases as the climate warms, and this rate of increase depends on the initial mixing strength, linking the mixing to cloud feedback. The mixing inferred from observations appears to be sufficiently strong to imply a climate sensitivity of more than 3 degrees for a doubling of carbon dioxide. This is significantly higher than the currently accepted lower bound of 1.5 degrees, thereby constraining model projections towards relatively severe future warming.

http://www.nature.com/nature/journal/v505/n7481/full/nature12829.html

We are headed well beyond a doubling. We know even at 400-500 ppm the climate was 4-5 degrees C warmer from paleorecords....you think some how the physics have changed?????

You remind me of the guy that wants to cheap out on the dikes....nah never gonna get that high.....

The world needs to get to carbon neutral - taking a chance that the climate is less sensitive is a fools bet.

So is 4.5C + a sure thing by 2100? nope.
Is less than 4.5 C a sure thing?? also no.

I'd tend to bet the 4.5 C is more likely than holding it to 2C as is/was called for.

The POINT of the cartoon was to put the meddling in perspective in a humorous way. Clearly you need a new prescription.

 

[macdoc]

TBH I'm pessimistic about us actually doing anything about climate change. I think the only thing that may save us from this emissions scenario is simply running out of easily available fossil fuels.

Which with fracking pushing off peak oil seems less and less likely

 

[aleCcowaN]

IPCC scenario A2 (relatively slow action dealing with CO2 emissions and population growth) yields a like range of temperature increase of 2.0 - 5.4 Deg C with a best estimate increase of 3.4 Deg C by 2100 relative to early 1990's and a little under 4.5 relative to 1900.

That's old. Here are the graphics from AR5.

Can we agree on every new IPCC AR replacing the old one?

 

[Trakar]

I agree about such disagreement. And thank you for replying offering clarifications. An attitude to be emulated.

About clarifications, just one, if by saying «we are looking at a tripling (at least) of pre-industrial CO2 ratios (~750-1000ppm), and conditions that have not been seen since mammals have been the dominant major forms of life on this planet.» you were implying in any way or measure that our planet is going to show that moment or a few decades after that moment the climate it experienced during such ancient eras.

In general, it is my understanding* that full climate equilibration to factors such as CO2 forcing require several centuries or more before the various climate elements are stabilized at the current level. This is why there are two measures of climate sensitivity to such issues, short-term and longer-term sensitivities. If you are asking me if I expect the general climate to reflect prehistoric climate episodes in the past that were slowly and naturally equilibrated to such levels as soon (or even shortly thereafter) as the modern climate forcings touch upon those prehistoric markers, the answer is, "no." Nor do I believe such was implicit in my statements which contain the qualification that:

...For instance, it is important to understand that even if we could stop all human-sourced emissions tomorrow, the atmospheric changes are already set much higher than the system has equilibrated to as of yet. In other words, if we stopped tomorrow, temperatures and climate changes will continue to occur for several more centuries before all of the feed back systems have brought the climate response up to the forcing level of the GHGs in the atmosphere...

...If this is not what you are asking me, please clarify your question.

*References for climate sensitivity and equilibration for atmospheric CO2:

"Global Warming: The Science of Climate Change - Climate Sensitivity"
Dept. of Geophysical Sciences, University of Chicago - Professor David Archer
(4:38 sec. video lecture clip)
http://www.kaltura.com/index.php/ex...f_id/20652192/entry_id/1_y7pofyu4/embed/auto?

"High Earth-system climate sensitivity determined from Pliocene carbon dioxide concentrations" - Mark Pagani, Zhonghui Liu, Jonathan LaRiviere and Ana Christina Ravelo (full paper available at - http://people.earth.yale.edu/sites/default/files/files/Pagani/1_2009 Pagani_NatureGeosci.pdf)

abstract - Climate sensitivity—the mean global temperature response
to a doubling of atmospheric CO2 concentrations through radiative forcing and associated feedbacks—is estimated at 1.5–4.5°C (ref. 1). However, this value incorporates only relatively rapid feedbacks such as changes in atmospheric
water vapour concentrations, and the distributions of sea ice, clouds and aerosols. Earth-system climate sensitivity, by contrast, additionally includes the effects of long-term feedbacks such as changes in continental ice-sheet extent, terrestrial ecosystems and the production of greenhouse gases other than CO2. Here we reconstruct atmospheric carbon dioxide concentrations for the early and middle Pliocene, when temperatures were about 3–4°C warmer than preindustrial values, to estimate Earth-system climate sensitivity from a
fully equilibrated state of the planet. We demonstrate that only a relatively small rise in atmospheric CO2 levels was associated with substantial global warming about 4.5 million years ago, and that CO2 levels at peak temperatures were between about 365 and 415 ppm. We conclude that the Earth-system climate sensitivity has been significantly higher over the past five
million years than estimated from fast feedbacks alone.

"Millennial Atmospheric Lifetime of Anthropogenic CO2" - David Archer,
Victor Brovkin (full paper available at - http://link.springer.com/article/10.1007/s10584-008-9413-1)

Abstract - The notion is pervasive in the climate science community and in the public at large that the climate impacts of fossil fuel CO2 release will only persist for a few centuries. This conclusion has no basis in theory or models of the atmosphere / ocean carbon cycle, which we review here. Although the models vary widely in their formulation and underlying assumptions, they are quite consistent in their prediction that release of fossil
fuel CO2 will impact climate for tens of millennia and longer into the future, subsiding on time scales typically associated with nuclear waste. Many slowly-responding components of the climate system, such as ice sheets, deep ocean temperature, permafrost, and methane hydrates, will be sensitive to the long tail of the CO2 climate impact. Most of the CO2 drawdown will take place on time scales of centuries, as CO2 invades the ocean, but it is too simplistic to call the invasion timescale the atmospheric lifetime of the CO2, as is commonly done in popular and scientific discussion. We argue that a better shorthand for the lifetime of anthropogenic CO2 would be "hundreds of years
plus a significant fraction that changes climate forever".

(I just noticed that this abstract is from a copy of the pre-publication paper that I have, the published abstract is a touch different and I am including it as it is on the published paper which appears at the above link -
" Abstract - The notion is pervasive in the climate science community and in the public at large that the climate impacts of fossil fuel CO2 release will only persist for a few centuries. This conclusion has no basis in theory or models of the atmosphere/ocean carbon cycle, which we review here. The largest fraction of the CO2 recovery will take place on time scales of centuries, as CO2 invades the ocean, but a significant fraction of the fossil fuel CO2, ranging in published models in the literature from 20–60%, remains airborne for a thousand years or longer. Ultimate recovery takes place on time scales of hundreds of thousands of years, a geologic longevity typically associated in public perceptions with nuclear waste. The glacial/interglacial climate cycles demonstrate that ice sheets and sea level respond dramatically to millennial-timescale changes in climate forcing. There are also potential positive feedbacks in the carbon cycle, including methane hydrates in the ocean, and peat frozen in permafrost, that are most sensitive to the long tail of the fossil fuel CO2 in the atmosphere."

I include both versions as they are a reflection of the authors' original findings and the modifications that are presumably tied to the science/editorial review that is a part of journal publication.)

 

[Trakar]

TBH I'm pessimistic about us actually doing anything about climate change. I think the only thing that may save us from this emissions scenario is simply running out of easily available fossil fuels.

I become increasingly pessimistic, that said, natural disaster and widespread war and economic collapse are also factors which can disrupt the processes of a ruthlessly efficient economic conversion of fossil fuels into atmospheric carbon. Not that these are preferable, but they are increasingly a potential factor moving forward.

 

[aleCcowaN]

In general, it is my understanding* that full climate equilibration to factors such as CO2 forcing require several centuries or more before the various climate elements are stabilized at the current level. This is why there are two measures of climate sensitivity to such issues, short-term and longer-term sensitivities. If you are asking me if I expect the general climate to reflect prehistoric climate episodes in the past that were slowly and naturally equilibrated to such levels as soon (or even shortly thereafter) as the modern climate forcings touch upon those prehistoric markers, the answer is, "no." Nor do I believe such was implicit in my statements which contain the qualification that:
...If this is not what you are asking me, please clarify your question.

That's exactly what I was asking. I am relieved that was your answer. It wasn't very logical that whole discussion with posts about hockey sticks and eons, telling that the past has no bearing and yet giving comparative scenarios.

If our emissions ceased today cold turkey, our global temperatures will continue to go up a few tenths of a degree for a few decades and then start to drop again into a pre-industrial-like level, maybe in a thousand years.

" Abstract - The notion is pervasive in the climate science community and in the public at large that the climate impacts of fossil fuel CO2 release will only persist for a few centuries. This conclusion has no basis in theory or models of the atmosphere/ocean carbon cycle, which we review here. The largest fraction of the CO2 recovery will take place on time scales of centuries, as CO2 invades the ocean, but a significant fraction of the fossil fuel CO2, ranging in published models in the literature from 20–60%, remains airborne for a thousand years or longer. Ultimate recovery takes place on time scales of hundreds of thousands of years, a geologic longevity typically associated in public perceptions with nuclear waste. The glacial/interglacial climate cycles demonstrate that ice sheets and sea level respond dramatically to millennial-timescale changes in climate forcing. There are also potential positive feedbacks in the carbon cycle, including methane hydrates in the ocean, and peat frozen in permafrost, that are most sensitive to the long tail of the fossil fuel CO2 in the atmosphere."

Interesting to compare. I'm going to take a look at the paper which resembles something I read a couple of years ago (but tomorrow, now here it's time to sleep in front of the TV) but one clarification. I stand for what I said in the above quote, but I said "today", because the mid and deep ocean is yet mostly in "pristine" conditions CO2-wise. I tend to reject the notion that an important part of human-added CO2 would remain airborne longer than that.

But if we are talking of a persistent human misbehaviour, as if we were in 2060, my phrase "if we ceased today cold turkey ..." would be certainly followed by a different text. A CO2 level of 750-1000 ppmv certainly is going to have longer-lasting consequences. My perception is we are unwilling to avoid reaching 550 ppmv in some 40 years, but no way we're going beyond. The climate crisis is perfectly solvable today with what we know and have. One day not only it will continue to be solvable; it will be also solved. And I don't consider myself to be an optimistic, on the contrary, as I'm always looking at totalities. I don't simply link the apparent lack of response to the problem around me to my expectations.

 

[Trakar]

That's old. Here are the graphics from AR5.

http://www.climatechange2013.org/images/figures/WGI_AR5_Fig12-3.jpg
(graph a )
SRES - A2 looks to be hitting ~7°C by 2100; there was a time I would have considered that horrifying to contemplate, now, I merely consider that an unrealistically conservative estimation for BAU.

 

[macdoc]

I haz a question on AR5..

2.4 to 3.5 C maximum

versus from the same graph ensembles.

2. to 5

Taking out further.....

Geez that is NOT long term in human history terms.....2000 ppm!!!!!

No wonder the Germans are dour...

Summary

The Task Group 'RCP Concentrations Calculation and Data' harmonised and consolidated greenhouse gas concentration and emission datasets for the pre-industrial control runs, 20th century, and the Representative Concentration Pathways (RCPs). The mixing ratios for the long-lived greenhouse gases provided below are the CMIP5 recommendation for Earth System Models in preparation of the IPCC Fifth Assessment Report. On this website: we provide as well additional background data, which is NOT part of the CMIP5 recommendations. For more information, please see the central CMIP5 PCMDI website and the RCP emission scenario database and our documentation: M. Meinshausen, S. Smith, et al. "The RCP Greenhouse Gas Concentrations and their extension from 1765 to 2500" (2011), Climatic Change (Special Issue on RCPs) (PDF) (HTML)

http://www.pik-potsdam.de/~mmalte/rcps/

Key item

Do nothing I assume is RCP8.5

RCP8.5:
High RCP, stabilising emissions post-2100, concentrations post-2200 (2005-2500):

Fig. Global Anthropogenic Radiative Forcing for
the high RCP8.5,
the medium-high RCP6,
the medium-low RCP4.5
and the low RCP3-PD.
In addition, two supplementary extensions are shown, connecting RCP6.0 levels to RCP4.5 levels by 2250 (SCP6TO45) or RCP45 levels to RCP3PD concentrations and forcings (SCP45to3PD). No uncertainty ranges are shown and reported, as for creating the recommendation datasets for CMIP5, central estimates have been assumed closely

Well there seems no question we COULD push 4.5C by 2100

 

[Trakar]

...I'm going to take a look at the paper which resembles something I read a couple of years ago (but tomorrow, now here it's time to sleep in front of the TV)

It's been a tough summer and fall, there. I hope you enjoyed a hoppy ale or two to celebrate a late fall afternoon/evening,...the sun is still up here and my air conditioner will probably keep running for another few hours yet,...a hoppy ale or two sounds good to me, see you on the morrow.

 

[macdoc]

Alec

I tend to reject the notion that an important part of human-added CO2 would remain airborne longer than that.

argue with Archer...is 25% an "important part"??

Popular books on climate change — even those written by scientists — if they mention the lifetime of CO2 at all, typically say it lasts "a century or more"1 or "more than a hundred years".

"That's complete nonsense," says Ken Caldeira of the Carnegie Institution for Science in Stanford, California. It doesn't help that the summaries in the Intergovernmental Panel on Climate Change (IPCC) reports have confused the issue, allege Caldeira and colleagues in an upcoming paper in Annual Reviews of Earth and Planetary Sciences2.

Now he and a few other climate scientists are trying to spread the word that human-generated CO2, and the warming it brings, will linger far into the future — unless we take heroic measures to pull the gas out of the air.

University of Chicago oceanographer David Archer, who led the study with Caldeira and others, is credited with doing more than anyone to show how long CO2 from fossil fuels will last in the atmosphere. As he puts it in his new book The Long Thaw,

"The lifetime of fossil fuel CO2 in the atmosphere is a few centuries, plus 25 percent that lasts essentially forever. The next time you fill your tank, reflect upon this"3.

"The climatic impacts of releasing fossil fuel CO2 to the atmosphere will last longer than Stonehenge," Archer writes. "Longer than time capsules, longer than nuclear waste, far longer than the age of human civilization so far."

http://www.nature.com/climate/2008/0812/full/climate.2008.122.html

 

[CoolSceptic]

Well there seems no question we COULD push 4.5C by 2100

Firstly, don't forget, the cartoon you appeared to endorse as making a point did not say "could" happen, it said "will" happen.

So, when does the 0.4C / decade rise kick in, macdoc, in your cloud cuckoo land scenario that "could" happen? When does the temperature start behaving anything remotely like that "could" happen?

Bear in mind if you wait for a few decades before it kicks in, the rate needs to jump to even higher in later years (hint: ain't gonna happen, short of some bizarre event like a massive asteroid strike hitting Antarctica, and even then extreme cooling is more likely than extreme heat)

The current decadal rate is struggling to maintain 0.1C / decade by most measures, the bizarre scenario of +0.4C /decade is about as credible as those expecting -0.2C / decade. And if you think people with an expectation of -0.2C / decade are crazy deniers, remember your expectation has a similar delta from the current rate, and is about as plausible.

 

[CoolSceptic]

IPCC scenario A2 (relatively slow action dealing with CO2 emissions and population growth) yields a like range of temperature increase of 2.0 - 5.4 Deg C with a best estimate increase of 3.4 Deg C by 2100 relative to early 1990's and a little under 4.5 relative to 1900.

http://www.ipcc.ch/publications_and_data/ar4/wg1/en/spmsspm-projections-of.html

The A2 scenario does result in higher temperatures than most of all the ones the IPCC uses, but it's essentially the "what happens if we do nothing about global warming" scenario so it may be appropriate to use in this case.

TBH I'm pessimistic about us actually doing anything about climate change. I think the only thing that may save us from this emissions scenario is simply running out of easily available fossil fuels.

I agree with you that we are unlikely to take much significant effective action towards reducing GHG emissions, although I'm not so much pessimistic on that point.

I strongly disagree that the numbers in the IPCC report are remotely credible, though. Obviously I'll never persuade the true believers that populate this thread, but just making the statement for the record

 

[DC]

Firstly, don't forget, the cartoon you appeared to endorse as making a point did not say "could" happen, it said "will" happen.

So, when does the 0.4C / decade rise kick in, macdoc, in your cloud cuckoo land scenario that "could" happen? When does the temperature start behaving anything remotely like that "could" happen?

Bear in mind if you wait for a few decades before it kicks in, the rate needs to jump to even higher in later years (hint: ain't gonna happen, short of some bizarre event like a massive asteroid strike hitting Antarctica, and even then extreme cooling is more likely than extreme heat)

The current decadal rate is struggling to maintain 0.1C / decade by most measures, the bizarre scenario of +0.4C /decade is about as credible as those expecting -0.2C / decade. And if you think people with an expectation of -0.2C / decade are crazy deniers, remember your expectation has a similar delta from the current rate, and is about as plausible.

well increased rates of warming are far more realistic than any cooling.

the CO2 forcing is getting bigger and bigger. positive feedbacks are getting stronger, less sea ice = albedo change etc.

no forcing in sight that could bring any cooling.