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Runaway Global Warming - Has Arrived pt 14

Re: Runaway Global Warming - Has Arrived pt 14

Unread postby Outcast_Searcher » Tue 04 Apr 2017, 14:42:07

baha wrote:Using a climate model to predict reality is like using a computer game to learn to ride a dirt-bike. Somebody's going to get hurt...

So your alternative is what?

That we ignore reality, by claiming climate models being imperfect (as all complex models are) makes them the enemy of the good?

Or do you have a productive alternative on how to try to predict climate in a "reasonably" accurate way, given our current level of technology and science?

Hint: Ignoring reality may be fine for ostriches. Given BAU, limits to growth, and the current size of the human population, ignoring reality isn't fine for humans.
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Re: Runaway Global Warming - Has Arrived pt 14

Unread postby baha » Wed 05 Apr 2017, 06:41:56

My problem is they present model results like it is fact. 'There will be 3 meters of sea level rise by 2100' Never mind that the margin of error is from 0 - 20 meters :)

Most people don't understand that computer models are just an educated guess.

The reality being ignored is how far events have diverged from the models. The idea that it's only 3 meters and we can adapt is what's stopping us from realizing just how screwed we are.
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Re: Runaway Global Warming - Has Arrived pt 14

Unread postby baha » Wed 05 Apr 2017, 07:16:32

We can update the models based on new/old data and events in the past. All while the future is diverging even more and continuing to slap us in the face.
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Re: Runaway Global Warming - Has Arrived pt 14

Unread postby dohboi » Wed 05 Apr 2017, 07:22:01

baha wrote:
...they present model results like it is fact. 'There will be 3 meters of sea level rise by 2100'


Sorry, I must have missed something. Who is the 'they' and where exactly did you drawing that quote from?
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Re: Runaway Global Warming - Has Arrived pt 14

Unread postby dissident » Wed 05 Apr 2017, 08:01:55

The typical denier attempt at smear. To claim models are treated as absolutist, religious texts. Utter libel. Climate model results are treated as statistical probability distribution functions (PDFs). Simulations are run as ensembles. The goal is to map out the energy budget change impact on the global circulation and weather regimes and not specific weather states. The routine BS from deniers that climate models are "forecasts" like those for weather is a combination of malice and ignorance. There is no forecasting of weather states, there is an attempt to quantify the energy accumulation and associated PDFs of weather regimes. For example, changes in the middle latitude storm tracks are very important for the impact of weather on agriculture and other human activity. Storm tracks are characterized by PDFs and they respond to changes in energy in the system. For example, the intensification of the Hadley circulation results in more baroclinic eddy generation in the subtropical jets.

Only a twit would nitpick at the 3 m sea level rise. BTW, baha, the latest IPCC round of model simulations only predicts a 1 meter rise. But it is clear that ice sheet dynamics are a weak point of models. They have not and for the most part still aren't coupled to proper ice sheet models. The permafrost is another part of the system that is basically not modeled since the climate GCMs are not coupled to full soil and permafrost models. So climate GCMs underestimate sea level rise and CH4 emissions. Actually, these climate GCMs don't even simulate CH4 and other greenhouse gas emissions, instead the emissions are estimated offline and used as boundary condition inputs.

We already had 4 meter higher sea levels during the Eemian interglacial 125,000 years ago. And the CO2 was not even higher than 320 ppmv (unlike today when it is close to 410 ppmv). Antarctica did not participate in the sea level rise during this period, it was all Greenland thanks to higher insolation in spring time in the northern hemisphere due to the orbital configuration. The ice sheets of both Greenland and Antarctica are being visibly destabilized at modern times so 3 m is just the start.
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Re: Runaway Global Warming - Has Arrived pt 14

Unread postby baha » Wed 05 Apr 2017, 09:39:57

I think evilgenius made the right call, I am ME and 'they' are everyone else. Single quotes means paraphrased. So that is MY interpretation of the crap I hear from THEM.

dissident - I agree completely. But your scientific analysis is way beyond J6P. He just takes what Fox news says literally.

As long as this is a debate and we consider adaptation an option, we will mostly die off. Who am I kidding...too late...we will mostly die off :)
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Re: Runaway Global Warming - Has Arrived pt 14

Unread postby baha » Wed 05 Apr 2017, 15:54:39

That's funny but a good example...They may have said 1 meter, I heard 3. My brain doesn't allow me to hide from the truth.
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Re: Runaway Global Warming - Has Arrived pt 14

Unread postby Cid_Yama » Tue 11 Apr 2017, 11:06:00

How Weird Winter Weather Battered America
It’s not your imagination. The weather has been weird.

So weird, in fact, it’s had an almost biblical feel: a February tornado in Massachusetts; record wildfires across the Great Plains and beyond; more snow than ever in the Sierra Nevada; and temperatures whiplashing from balmy to frigid, killing crops and coaxing flowers out of their winter slumber.

While some of the swings may result from chance, scientists agree climate change is adding to weather mayhem and that the world will have to brace for worse. President Donald Trump is also seeking to roll back measures to fight global warming, saying the regulations kill jobs.

“The bottom line: It’s not just in our minds that the weather is changing,” said David Titley, a meteorology professor at Pennsylvania State University. “It is changing, and changing rapidly in ways we understand and ways we are just beginning to examine.”

Start with the temperature. The winter of 2016-17 marked the second mildest on record, according to Jake Crouch, a climate scientist with the National Centers for Environmental Information. February, which has been warming faster than any other month through the decades, also was the second warmest in the 138-year global record. There were some bizarre temperature readings along the way. Like a high of 70 degrees Fahrenheit (21 Celsius) in Chicago on Feb. 18. Or 72 degrees in Boston less than a week later.

The month was so mild that natural gas inventories rose earlier than in any year going back to 1994, when records began, and plants threw off winter’s yoke and began to grow.

Then came the March chill.

In Kentucky, winter wheat plants poked their heads above ground four to six weeks ahead of schedule, then risked their lives in a cold snap.

“We’re not surprised by a freeze this time of year,” said Carrie Knott, a grain crops agronomist with University of Kentucky Extension. “It’s just that crop had developed so much.”

In Georgia and South Carolina, peaches froze. In Washington, cherry blossoms fell off branches. Georgia could end up losing 80 percent of its blueberry crop, leading state Agriculture Commissioner Gary Black to call it “the tornado or hurricane of many of our growers’ lives.”

Through March 24 this year, 2.1 million acres had burned across the U.S., according to the U.S. National Interagency Fire Center in Boise, Idaho—six times the decade average for the first quarter. Humans started many of the fires, but warm and dry weather spread them, according to Jessica Gardetto, spokeswoman for the center, which coordinates wildfire fighting.

As if that weren’t enough, winter’s unusually warm, moist air brought tornado reports—486 of them, to be exact, since the start of the year. That’s almost a record.

The twisters reached as far north as Massachusetts, a state better known for blizzards.

Dave Chichester, the emergency management director in Conway, left town one late February day to sunny skies and 60-degree temperatures for a trip to Maine. A few hours later, he got a call from local officials urging him to come home quickly. Some kind of storm had swept through the area, damaging nine buildings and knocking down hundreds of trees.

No one was hurt, but he heard some harrowing tales.

“People having dinner with guests in the back of a house, and the front of the house disappeared,” Chichester said. “There was a sense of incredibility.”

A day later, officials confirmed it was a tornado, the first ever in a state that began documenting its weather patterns back in the 1600s.

http://www.agweb.com/article/how-weird- ... rica-blmg/
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Re: Runaway Global Warming - Has Arrived pt 14

Unread postby dohboi » Tue 11 Apr 2017, 14:58:17

MN had its earliest tornado by about ten days, iirc. It went through the back yard of one of my students.
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Re: Runaway Global Warming - Has Arrived pt 14

Unread postby jedrider » Tue 11 Apr 2017, 15:13:52

Wildfire Outbreak Prompts Florida Governor to Declare State of Emergency

https://weather.com/news/news/florida-wildfires-governor-impacts

Best 'educated guess' is that we are already in 'runaway' territory IMO.
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Re: Runaway Global Warming - Has Arrived pt 14

Unread postby Plantagenet » Tue 11 Apr 2017, 16:37:30

A new study published in NATURE predicts that 40% of the earth's permafrost will disappear even if the world keeps to the much ballyhooed Paris Accord's 2°C target for global warming

40% of the earth's permafrost to disappear

That does't seem so worrisome until you realize that permafrost contains huge amounts of carbon. When the PF thaws the carbon is released to the atmosphere creating a giant postiive feedback loop.

More global warming means more PF loss means more CO2 releases means more global warming means runaway global warming.

Cheers!

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40% of the world's permafrost is about to disappear----releasing huge amounts of CO2.

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Re: Runaway Global Warming - Has Arrived pt 14

Unread postby Cid_Yama » Tue 11 Apr 2017, 20:45:46

Since it will be wet, more methane than CO2 from terrestrial permafrost, and during the spring thaw, lots of nitrous oxide.
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Re: Runaway Global Warming - Has Arrived pt 14

Unread postby Plantagenet » Tue 11 Apr 2017, 23:59:34

Cid_Yama wrote:Since it will be wet, more methane than CO2 from terrestrial permafrost, and during the spring thaw, lots of nitrous oxide.


Some will be wet and some will be dry---. :)

The surface of the ground in areas with thick permafrost is often swampy because ground ice is an aquiclude----i.e. water at the surface is perched above the permafrost.

However in areas with thin discontinuous permafrost the ground can be well drained and dry.

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Re: Runaway Global Warming - Has Arrived pt 14

Unread postby dohboi » Wed 12 Apr 2017, 01:31:04

There are lots of other things going on that can influence the dryness/wetness of the permafrost. With a more and more open Arctic Ocean, there will be more humidity in the air, which both directly reduces drying and also produces more frequent precipitation events. On the other hand, the increased warmth will tend to dry areas out that happen to miss said precip events. And increasingly disturbed and 'stuck' atmospheric circulation patters will likely mean that some areas become very much more wet, while others become so dry that they will be more and more prone to catching fire, as we have seen in recent years.
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Re: Runaway Global Warming - Has Arrived pt 14

Unread postby Cid_Yama » Fri 14 Apr 2017, 03:45:03

Seep mounds are carbonate deposits, often hosting unique fauna, which form at sites of methane leakage into the seafloor. Over 130 were found covering over 10,000 square kilometers of the Cretaceous sea floor. They occurred over a very short time interval immediately following onset of Cretaceous global warming, suggesting that the warming destabilized gas hydrates and released a large burb of methane. Given that methane has 20 times (87 times over 20 years) the impact of CO2 as a greenhouse gas, such a release could have accelerated global warming at that time. This discovery supports concerns of potential destabilization of modern methane hydrates.

A key feature of this discovery is recognition that all the seep mounds formed during a very narrow range of geologic time. Because they form by leakage of methane into seawater it implies that something at that time caused a large release of methane into the ocean. The timing is coincident with a period of global warming, and Williscroft and colleagues suggest that it was this warming that released methane frozen as methane hydrates in the sea floor, as a relatively sudden methane "burp." If correct, this has important implications for modern warming of the Arctic Ocean. Similar frozen methane hydrates occur throughout the same arctic region as they did in the past, and warming of the ocean and release of this methane is of key concern as methane is 20x (87 times over 20 years) the impact of CO2 as a greenhouse gas. Release of methane hydrates has previously been suggested as a mechanism to drive runaway greenhouse events, as warming oceans releases trapped methane that causes further warming and releases more methane. The extensive methane seep mounds across the remote arctic island of Ellef Ringnes may be a caution from the past regarding potential impacts of modern warming of the Arctic Ocean.

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Extensive Early Cretaceous (Albian) methane seepage on Ellef Ringnes Island, Canadian High Arctic
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Re: Runaway Global Warming - Has Arrived pt 14

Unread postby GASMON » Fri 14 Apr 2017, 04:15:29

A spectacular iceberg has been spotted close to shore in Newfoundland

http://www.telegraph.co.uk/news/2017/04 ... rg-season/

Canada is set for a record iceberg season with hundreds already visible off the coast of Newfoundland and Labrador.

They appear to have arrived earlier than usual, with Canada’s iceberg season normally taking place later in the summer.

At the last count there are already 481 icebergs in the region

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Re: Runaway Global Warming - Has Arrived pt 14

Unread postby dohboi » Sat 15 Apr 2017, 21:15:27

Thanks to ASLR at neven's site for this list:

28 references [not including either von der Heydt et. al. 2016 nor Friedrich et al (2016)] that either directly, or indirectly, indicate that climate sensitivity is most likely significantly higher than the range summarized by AR5:

1. The linked reference analyses the CMIP3&5 results to conclude the ECS is likely 3.9C +/- 0.45C:

Chengxing Zhai, Jonathan H. Jiang & Hui Su (2015), "Long-term cloud change imprinted in seasonal cloud variation: More evidence of high climate sensitivity", Geophysical Research Letters, DOI: 10.1002/2015GL065911


http://onlinelibrary.wiley.com/doi/10.1 ... 65911/full

2. The linked reference provides findings from CMIP5 of the continued poleward expansion of the Hadley Cell with continued global warming; which in-turn supports the idea that ECS is greater than 3C:

Lijun Tao, Yongyun Hu & Jiping Liu (May 2016), "Anthropogenic forcing on the Hadley circulation in CMIP5 simulations", Climate Dynamics, Volume 46, Issue 9, pp 3337-3350 DOI: 10.1007/s00382-015-2772-1

http://rd.springer.com/article/10.1007% ... 015-2772-1

3. The linked reference presents new paleo evidence about the Eocene. While the authors emphasize that their findings support the IPCC interpretation for climate sensitivity, when looking at the attached Fig 4 panel f, it appears to me that this is only the case if one averages ECS over the entire Eocene; while if one focuses on the Early Eocene Climate Optimum (EECO) which CO₂ levels were higher than in current modern times, it appear that ECS was higher (around 4C) than the IPCC AR5 assumes (considering that we are increasing CO2 concentrations faster now that during the EECO this gives me concern rather than reassurance).

Eleni Anagnostou, Eleanor H. John, Kirsty M. Edgar, Gavin L. Foster, Andy Ridgwell, Gordon N. Inglis, Richard D. Pancost, Daniel J. Lunt & Paul N. Pearson (2016), "Changing atmospheric CO2 concentration was the primary driver of early Cenozoic climate", Nature, doi:10.1038/nature17423


http://www.nature.com/nature/journal/va ... 17423.html

4. Tan et al (2016) indicates that ECS may well be between 5.0 and 5.3C.

Ivy Tan, Trude Storelvmo & Mark D. Zelinka (08 Apr 2016), "Observational constraints on mixed-phase clouds imply higher climate sensitivity", Science, Vol. 352, Issue 6282, pp. 224-227, DOI: 10.1126/science.aad5300


http://science.sciencemag.org/content/352/6282/224

5. According to the IPCC AR5 report: "The transient climate response is likely in the range of 1.0°C to 2.5°C (high confidence) and extremely unlikely greater than 3°C"; however, the linked reference uses only observed data to indicate that TCR is 2.0 +/- 0.8C. Thus AR5 has once again erred on the side of least drama.


T. Storelvmo, T. Leirvik, U. Lohmann, P. C. B. Phillips & M. Wild (2016), "Disentangling greenhouse warming and aerosol cooling to reveal Earth’s climate sensitivity", Nature Geoscience, doi:10.1038/ngeo2670


http://www.nature.com/ngeo/journal/vaop ... o2670.html

6. The linked reference reassesses ECS from CMIP3 &5 and find an ensemble-mean of 3.9C, and I note that CMIP3&5 likely err on the side of least drama as they ignore several important non-linear slow feedbacks that could be accelerated by global warming:

Chengxing Zhai, Jonathan H. Jiang, Hui Su (2015), "Long-term cloud change imprinted in seasonal cloud variation: More evidence of high climate sensitivity", Geophysical Research Letters, DOI: 10.1002/2015GL065911

http://onlinelibrary.wiley.com/doi/10.1 ... 65911/full

7. The linked reference could not make it more clear that paleo-evidence from inter-glacial periods indicates that ECS is meaningfully higher than 3C and that climate models are commonly under predicting the magnitude of coming climate change.

Dana L. Royer (2016), "Climate Sensitivity in the Geologic Past", Annual Review of Earth and Planetary Sciences, Vol. 44


http://www.annualreviews.org/doi/abs/10 ... src=recsys

8. Thompson indicates that ECS has a 95%CL range of from 3C to 6.3C, with a best estimate of 4C, and Sherwood (2014) has a higher value still:

Climate sensitivity by Roy Thompson published by Earth and Environmental Science Transactions of the Royal Society of Edinburgh, DOI: 10.1017/S1755691015000213

http://journals.cambridge.org/action/di ... 1015000213


9. Tian (2015) indicates that the double-ITCZ bias constrains ECS to its high end (around 4.0C):

Tian, B. (2015), "Spread of model climate sensitivity linked to double-Intertropical Convergence Zone bias", Geophys. Res. Lett., 42, doi:10.1002/2015GL064119.


http://onlinelibrary.wiley.com/doi/10.1 ... 9/abstract

10. Sherwood et al (2014), which found that ECS cannot be less than 3C, and is likely currently in the 4.1C range. Also, everyone should remember that the effective ECS is not a constant, and models project that following a BAU pathway will result in the effective ECS increasing this century:


Sherwood, S.C., Bony, S. and Dufresne, J.-L., (2014) "Spread in model climate sensitivity traced to atmospheric convective mixing", Nature; Volume: 505, pp 37–42, doi:10.1038/nature12829

http://www.nature.com/nature/journal/v5 ... 12829.html

11. The linked reference studies numerous climate models and finds that: "… those that simulate the present-day climate best even point to a best estimate of ECS in the range of 3–4.5°C."
Reto Knutti, Maria A. A. Rugenstein (2015), "Feedbacks, climate sensitivity and the limits of linear models", Philosophical Transactions of the Royal Society A, DOI: 10.1098/rsta.2015.0146

http://rsta.royalsocietypublishing.org/ ... 4/20150146

12. The linked reference indicates that the cloud feedback from tropical land is robustly positive. As AR5 did not know whether this contribution to climate sensitivity was positive or negative, this clearly indicates that AR5 errs on the side of least drama with regard to both TCR & ECS:

Youichi Kamae, Tomoo Ogura, Masahiro Watanabe, Shang-Ping Xie and Hiroaki Ueda (8 March 2016), "Robust cloud feedback over tropical land in a warming climate", Atmospheres, DOI: 10.1002/2015JD024525

http://onlinelibrary.wiley.com/doi/10.1 ... 5/abstract

13. Graeme L. Stephens, Brian H. Kahn and Mark Richardson (5 May, 2016), "The Super Greenhouse effect in a changing climate", Journal of Climate, DOI: http://dx.doi.org/10.1175/JCLI-D-15-0234.1


http://journals.ametsoc.org/doi/abs/10. ... -15-0234.1

14. The linked reference assumes different degrees of nonlinearity for climate feedback mechanisms and concludes that such nonlinearity for positive feedback represents a Black Swan risk that linear climate models cannot recognize:

Jonah Bloch-Johnson, Raymond T. Pierrehumbert & Dorian S. Abbot (24 June 2015), "Feedback temperature dependence determines the risk of high warming", Geophysical Research Letters, DOI: 10.1002/2015GL064240

http://onlinelibrary.wiley.com/doi/10.1 ... 64240/full


15. While the linked (open access) reference has many appropriate qualifying statements and disclaimers, it notes that the AR5 paleo estimates of ECS were linear approximations that change when non-linear issues are considered. In particular the find for the specific ECS, S[CO2,LI], during the Pleistocence (ie the most recent 2 million years) that:
"During Pleistocene intermediate glaciated climates and interglacial periods, S[CO2,LI] is on average ~ 45 % larger than during Pleistocene full glacial conditions."

Therefore, researchers such as James Hansen who relied on paleo findings that during recent full glacial periods ECS was about 3.0C, did not know that during interglacial periods this value would be 45% larger, or 4.35C.

Köhler, P., de Boer, B., von der Heydt, A. S., Stap, L. B., and van de Wal, R. S. W. (2015), "On the state dependency of the equilibrium climate sensitivity during the last 5 million years", Clim. Past, 11, 1801-1823, doi:10.5194/cp-11-1801-2015.


http://www.clim-past.net/11/1801/2015/c ... -2015.html
http://www.clim-past.net/11/1801/2015/c ... 1-2015.pdf

16. The linked reference implies that climate sensitivity (ESS) could be much higher than previously assumed:

Jagniecki,Elliot A. et al. (2015), "Eocene atmospheric CO2from the nahcolite proxy", Geology, http://dx.doi.org/10.1130/G36886.1


http://geology.gsapubs.org/content/earl ... 3/G36886.1

17. The linked open access reference identifies three constraints on low cloud formation that suggest that cloud feedback is more positive than previously thought. If verified this would mean that both TCR and ECS (and ESS) are larger than previously thought:

Stephen A. Klein and Alex Hall (26 October 2015), "Emergent Constraints for Cloud Feedbacks", Climate Feedbacks (M Zelinka, Section Editor), Current Climate Change Reports, pp 1-12, DOI 10.1007/s40641-015-0027-1

http://link.springer.com/article/10.100 ... 015-0027-1

18. The linked article indicates that values of TCR based on observed climate change are likely underestimated:

J. M. Gregory, T. Andrews and P. Good (5 October 2015), "The inconstancy of the transient climate response parameter under increasing CO₂", Philosophical Transactions of the Royal Society A, DOI: 10.1098/rsta.2014.0417


http://rsta.royalsocietypublishing.org/ ... 4/20140417

19. The linked reference indicates that most current climate models underestimate climate sensitivity:

J. T. Fasullo, B. M. Sanderson & K. E. Trenberth (2015), "Recent Progress in Constraining Climate Sensitivity With Model Ensembles", Current Climate Change Reports, Volume 1, Issue 4, pp 268-275, DOI 10.1007/s40641-015-0021-7

http://link.springer.com/article/10.100 ... nlineFirst

20. The linked reference indicates that studies that assuming linearity of climate sensitivity likely underestimate the risk of high warming.

Jonah Bloch-Johnson, Raymond T. Pierrehumbert and Dorian S. Abbot (June 2015), "Feedback temperature dependence determines the risk of high warming", Geophysical Research Letters, DOI: 10.1002/2015GL064240

http://onlinelibrary.wiley.com/doi/10.1 ... 0/abstract

21. The linked reference indicates that new research (from PlioMIP2) demonstrates that the climate sensitivity for the Pliocene was higher than previously believed (from PlioMIP1):

Kamae, Y., Yoshida, K., and Ueda, H.: Sensitivity of Pliocene climate simulations in MRI-CGCM2.3 to respective boundary conditions, Clim. Past, 12, 1619-1634, doi:10.5194/cp-12-1619-2016, 2016.

http://www.clim-past.net/12/1619/2016/

http://www.clim-past.net/12/1619/2016/c ... 9-2016.pdf


22. The linked reference indicates that corrected recent observations indicate that the most likely value of ECS may be as high as 4.6C (see attached plot of the time dependent curve):

Kyle C. Armour (27 June 2016), "Projection and prediction: Climate sensitivity on the rise", Nature Climate Change, doi:10.1038/nclimate3079

http://www.nature.com/nclimate/journal/ ... e3079.html

23. The linked reference indicates that the climate responses (climate sensitivities) projected by advanced climate models generally match observations when apple to apple comparisons are made. This is a useful finding as advanced climate models generally indicate that climate sensitivity values are towards the high end of the IPCC climate sensitivity range:

Mark Richardson, Kevin Cowtan, Ed Hawkins & Martin B. Stolpe (2016), "Reconciled climate response estimates from climate models and the energy budget of Earth", Nature Climate Change, doi:10.1038/nclimate3066

http://www.nature.com/nclimate/journal/ ... e3066.html

24. The linked reference discusses paleodata to indicate that climate sensitivity increased from 3.3 - 5.6 (mean of 4.45k) at the beginning of the PETM up to 3.7 - 6.5 K (mean of 5.1K) near the peak of the PETM; and that if we burn only the easily accessible carbon reserves then GMST could increase by about 10C. I note these climate sensitivity values are much higher than those inherent in the CMIP5 projections:

Gary Shaffer, Matthew Huber, Roberto Rondanelli & Jens Olaf Pepke Pedersen (23 June 2016), "Deep-time evidence for climate sensitivity increase with warming", Geophysical Research Letters, DOI: 10.1002/2016GL069243

http://onlinelibrary.wiley.com/doi/10.1 ... 69243/full


25. The linked Reuters article notes that NASA reported that a new satellite-based method have located 39 unreported sources of anthropogenic emissions that, when accounted for, increase our previously estimated amount of sulfur dioxide by about 12 percent of all such anthropogenic emissions from 2005 to 2014. This indicates that the CMIP5 projections also underestimated the impact of this negative forcing source; which raises the prospect that climate sensitivity (ECS) is likely higher than the CMIP5 models indicate, and the linked Zhai et al (2015) reference analyses of the CMIP3&5 results conclude that the ECS is likely 3.9C +/- 0.45C:

Chengxing Zhai, Jonathan H. Jiang & Hui Su (2015), "Long-term cloud change imprinted in seasonal cloud variation: More evidence of high climate sensitivity", Geophysical Research Letters, DOI: 10.1002/2015GL065911

http://in.reuters.com/article/us-nasa-p ... NKCN0YO1PW

26. The linked reference uses an information-theoretic weighting of climate models by how well they reproduce the satellite measured deseasonlized covariance of shortwave cloud reflection, indicates a most likely value of ECS of 4.0C; which indicates that AR5 errs on the side of least drama:

Florent Brient & Tapio Schneider (2016), "Constraints on climate sensitivity from space-based measurements of low-cloud reflection", Journal of Climate, DOI: http://dx.doi.org/10.1175/JCLI-D-15-0897.1


http://journals.ametsoc.org/doi/abs/10. ... -15-0897.1


27. The linked article indicates that the contribution of sea-ice loss to Arctic Amplification is regulated by the PDO and that in positive PDO phases (like we are in now) there should be less Arctic Amplification. Thus the fact that we are currently experiencing high Arctic Amplification during a period of highly positive PDO values gives cause for concern that climate sensitivity may be higher than considered by AR5:

James A. Screen & Jennifer A. Francis (2016), "Contribution of sea-ice loss to Arctic amplification is regulated by Pacific Ocean decadal variability", Nature Climate Change, DOI: 10.1038/nclimate3011


http://www.nature.com/nclimate/journal/ ... e3011.html


28. The linked reference uses an information-theoretic weighting of climate models by how well they reproduce the satellite measured deseasonlized covariance of shortwave cloud reflection, indicates a most likely value of ECS of 4.0C. As this satellite data is certainly biased by the recent acceleration of natural aerosol emissions associated with the increasing atmospheric CO2 concentration, the actually ECS is likely higher than 4.0C, as will become apparent if climate change reduces future plant activity. Unfortunately, the envisioned upgrades to the Paris Pact do not have any contingency for addressing such high values (4 to 4.5C) of ECS (including accelerting NET):

Florent Brient & Tapio Schneider (2016), "Constraints on climate sensitivity from space-based measurements of low-cloud reflection", Journal of Climate, DOI: http://dx.doi.org/10.1175/JCLI-D-15-0897.1


http://journals.ametsoc.org/doi/abs/10. ... -15-0897.1

And for those who do not like to read, I provide the two attached images of high equilibrium climate sensitivity, with the first based on paleo data, and the second based on modern observations.
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Re: Runaway Global Warming - Has Arrived pt 14

Unread postby pstarr » Sat 15 Apr 2017, 23:20:06

More proof it is not running away. Another important study in Nature to challenge the conventional wisdom.

Large historical growth in global terrestrial gross primary production

J. E. Campbell, J. A. Berry, U. Seibt, S. J. Smith, S. A. Montzka, T. Launois, S. Belviso, L. Bopp & M. Laine
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Nature 544, 84–87 (06 April 2017) doi:10.1038/nature22030
Received 10 January 2012 Accepted 23 February 2017 Published online 05 April 2017
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Growth in terrestrial gross primary production (GPP)—the amount of carbon dioxide that is ‘fixed’ into organic material through the photosynthesis of land plants—may provide a negative feedback for climate change1, 2. It remains uncertain, however, to what extent biogeochemical processes can suppress global GPP growth3. As a consequence, modelling estimates of terrestrial carbon storage, and of feedbacks between the carbon cycle and climate, remain poorly constrained4. Here we present a global, measurement-based estimate of GPP growth during the twentieth century that is based on long-term atmospheric carbonyl sulfide (COS) records, derived from ice-core, firn and ambient air samples5. We interpret these records using a model that simulates changes in COS concentration according to changes in its sources and sinks—including a large sink that is related to GPP. We find that the observation-based COS record is most consistent with simulations of climate and the carbon cycle that assume large GPP growth during the twentieth century (31% ± 5% growth; mean ± 95% confidence interval). Although this COS analysis does not directly constrain models of future GPP growth, it does provide a global-scale benchmark for historical carbon-cycle simulations.

In another words, plant photosynthesis was stable for hundreds of years before the industrial revolution, but grew rapidly in the 20th century. The researchers estimate that the sum of all plant photosynthesis on Earth grew by 30 percent over the 200-year record they captured.

So while the 2016 NOAA study on CO2 fertilization shows significant increased terrestrial vegetation since the Landstat program began in 1972, this new science reports similar increased plant growth dating back to the beginning of the industrial revolution. CO2 is good for plants :) And plants are good at taking up CO2. What a happy planet :)
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Re: Runaway Global Warming - Has Arrived pt 14

Unread postby Squilliam » Sun 16 Apr 2017, 01:48:14

Interesting to get a little bit of balance on this topic.
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Re: Runaway Global Warming - Has Arrived pt 14

Unread postby dohboi » Sun 16 Apr 2017, 05:55:08

There's nothing really new in p's article. We've known that there was some extra uptake of carbon by plants, as was expected. But the graphs attached to the article suggest that this effect peaked in about 1990. So it is not likely to help us much any more going forward, unfortunately.

This also means that crops have been getting less nutritious, more empty calories...another thing that might be behind the global obesity epidemic (though that can mostly be chalked up to Coke and other companies pushing their sugary products on the populace).
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