Guest essay by Eric Worrall
A study published in AAAS “Science Advances” has attempted to resurrect discredited claims of a dangerously high climate sensitivity, by suggesting that climate sensitivity increases as the world warms.
Climate change may be escalating so fast it could be ‘game over’, scientists warn
New research suggests the Earth’s climate could be more sensitive to greenhouse gases than thought, raising the spectre of an ‘apocalyptic side of bad’ temperature rise of more than 7C within a lifetime.
It is a vision of a future so apocalyptic that it is hard to even imagine.
But, if leading scientists writing in one of the most respected academic journals are right, planet Earth could be on course for global warming of more than seven degrees Celsius within a lifetime.
And that, according to one of the world’s most renowned climatologists, could be “game over” – particularly given the imminent presence of climate change denier Donald Trump in the White House.
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In a paper in the journal Science Advances, they said the actual range could be between 4.78C to 7.36C by 2100, based on one set of calculations.
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The abstract of the study;
Nonlinear climate sensitivity and its implications for future greenhouse warming
Global mean surface temperatures are rising in response to anthropogenic greenhouse gas emissions. The magnitude of this warming at equilibrium for a given radiative forcing—referred to as specific equilibrium climate sensitivity (S)—is still subject to uncertainties. We estimate global mean temperature variations and S using a 784,000-year-long field reconstruction of sea surface temperatures and a transient paleoclimate model simulation. Our results reveal that S is strongly dependent on the climate background state, with significantly larger values attained during warm phases. Using the Representative Concentration Pathway 8.5 for future greenhouse radiative forcing, we find that the range of paleo-based estimates of Earth’s future warming by 2100 CE overlaps with the upper range of climate simulations conducted as part of the Coupled Model Intercomparison Project Phase 5 (CMIP5). Furthermore, we find that within the 21st century, global mean temperatures will very likely exceed maximum levels reconstructed for the last 784,000 years. On the basis of temperature data from eight glacial cycles, our results provide an independent validation of the magnitude of current CMIP5 warming projections.
Read more: http://advances.sciencemag.org/content/2/11/e1501923
The money quote from the study full text;
… This paleodata-based TCRP is now applied to the RCP8.5 forcing scenario until year 2100 CE, following the equation above for deriving an estimated global mean SAT response. The anthropogenic forcing results in a global mean SAT anomaly of 5.86 K by year 2100 with respect to PI values. The uncertainties in S and the ocean’s heat uptake efficiency as discussed above result in a likely range of 4.78 to 7.36 K for the global mean SAT anomaly. Comparing our paleo-based estimate of future warming to the multimodel ensemble mean projections of the CMIP5 (52), we found that our projection results in a slightly higher global mean SAT anomaly. The current Intergovernmental Panel on Climate Change (IPCC)/CMIP5 projection under the RCP8.5 scenario results in a global mean SAT increase of 4.84 K for the year 2100 (with respect to PI values). The corresponding multimodel ensemble values range from 3.42 to 6.40 K. …
Read more: Same as above
My question – if a warmer world is more sensitive to CO2, why was the Cretaceous, which ended 66 million years ago, only 4C warmer than today, despite a CO2 level more than 4x higher than today’s CO2 level? If we apply the conclusions of the paper, temperatures in the warm Cretaceous should have been 14c higher than today’s temperatures – an absurdity which should excuse this paper from further serious consideration.
“Great! Let’s party like there’s no tomorrow! Yay! :” [see above]
This is a win-win proposition …. open the bottles!
Win Alt.1: If the ‘Tipping-Point’ is tomorrow, and the World is incinerated the day after, we win .. we go out with a ‘bang’. Eat, drink & be merry ‘cos tomorrow we die!!
Win Alt.2: The ‘Tipping-Point’ / cataclysmic consequence hypothesis (as fervently promoted by the colluding Alarmist pseudo-science cabal, and cheer-led by the opportunistic pols., money-grasping entrepreneurs drooling at the public trough, the sensationalist media, and Snake-Oil-Sales(wo)men) is WRONG. This is much the more plausible ‘cos Gaia has survived innumerable such ‘tipping-points’ [tho’ they didn’t know it at the time] and survived. Otherwise why does Gaia survive, and us with it? Eat, drink & be merry, ‘cos tomorrow we live!
In other words, there’s buggah-all we can do about it, so ‘Don’t worry, be happy!’
Added to which, on the paleo-climatic time scale, the Anthropocene is but a microcosmic slice. Ice-sheet cycles of advancing & retreating over tens of thousands of years over geological time reduce antropogenicity to a blink in time. The energy fluxes involved render any quantum of anthropogenic warming to infinitesimal. The CO2 & atmospheric variations far exceed anything we are microscopically contemplating in our ‘millisecond’s worth’ of existence on graphs determined by hugely inertial paleoclimatic swings, not anthropogenic. This all ‘big-pendulum’ cyclicity.
Ladies & Gentlemen … my case rests. Global Warming Alarmism is a self-serving scam
for self-serving gravy-trainers.
“My question – if a warmer world is more sensitive to CO2, why was the Cretaceous, which ended 66 million years ago, only 4C warmer than today, despite a CO2 level more than 4x higher than today’s CO2 level?
Be-be-because positive feedback loop! Yeah, that’s the ticket! More C02-> hotter temperatures -> more CO2 –> apocalypse.
Oh ok. Then how did the C02 level get DOWN from its high point 66 million years ago?
*Crickets*”
I’m just a lowly engineer, but I spotted that one several years ago. Amazingly, none of the AGW folks can give a coherent answer.
I say that you hit the nail on the head!
The fact that the apocalypses (supposedly irreversible post-‘tipping-points’ — ever so narrowly & precisely defined by the High Priests of Charlatanism) never occurred in paleo-climatic record despite innumerable ‘run-ins’ is surely an Incontrovertible, Inconvenient Truth that DEMOLISHES AGW/catastrophist theory.
( Johna: From one ‘lowly Engineer’ (CAP ‘E’ puhlease — stand proud Engineer!) to another lowly(?) *E*ngineer! what the rest of the World doesn’t know is that we Engineers likely have the broad grasp of scientific principles — albeit in an ‘Applied’ context — than most other professions … including “Climate Scientists” whatever that means Seems to me that any Tom, dick or Harry can hang-out their shingle saying: “Climate Scientist” whereas us poor Engineers go through living hell to get our professional qualifications, AND have to conform to litigation requiring us to be affiliated with a relevant pre-qualified Professional Group. I’ve yet to hear of an International Association of Qualified Climate Professions with Rules as rigorous as those governing ours.)
No wonder these Charlatans run-riot, without constraint, with slack-science …
Don’t get me going with supposedly the Platinum Standard of “Peer Review”…… we’ve all been ‘had’ and it’s hi-time the pendulum swung back *hard*
Eric: Here is a map of the continents during the Cretaceous Period. Ocean circulation and meridional transport of heat were dramatically different. Let’s not draw any meaningless conclusions about climate sensitivity from the temperature during the Cretaceous.
http://jan.ucc.nau.edu/~rcb7/105moll.jpg
Think of what the Earth’s Albedo was in this scenario.
ALL that ocean, which has a much lower Albedo than the land surface. Especially the shallow inland seas which have even lower Albedo than the normal deep ocean.
No glaciers, which have a much higher Albedo than any other change which can happen on the planet.
No land-mass at the poles (technically, Antarctica was a little higher north at this time than usually shown. The spreading oceanic ridge between Australia and Antarctica (where they started splitting apart about 50 Mya) puts Antarctica about 2,000 kms farther north than shown here).
If you actually run the numbers on what the global Albedo was, it is around 25.2% versus today’s 29.83%. That alone makes the Earth about 4.1C warmer.
To me the big unexplained mystery with this model based hypothesis is that given the vast range of combinations of atmospheric composition, geomorphic and tectonic change, sea level variation and the wide range of surface and ocean temperatures that have existed over aeons of planetary evolution, somehow no evidence exists that any of these endless combinations has led to a feedback induced point of instability or “tipping point”. That’s not to suggest that climate sensitivity doesn’t vary, clearly it will, but this experience does strongly indicate that in general the interaction of feedbacks tends toward the restoration of equilibrium.
So I was right all along, and we are doomed after all. That’s comforting to know.
Mayan Science
These studies really, really need to start with a line “We have yet to detect a hint of any trace of CO2 force feedbacks on water vapour as reported by the United Nations WMO and UN IPCC and 300 billion dollars has been spent in this pursuit to date.”
It used to be said that it took a bad physicist to draw a straight line through three points, a bad chemist to draw a straight line through two points, but a brilliant climate scientist to draw a straight line through one point.
The Thinker is a symbol of the sceptic. Not the grifter.
The only sort of feedback claimed for amplifying CO2 is through the rise in temperature. Higher temperature causes water vapour levels to rise which causes further warming and so on. That means whether the initial rise is due to CO2 or something else is completely irrelevant, it is the rise in temperature which causes the feedback. The claim is that the +ve feedback co-efficient rises as the temperature rises to the point that less than 1C direct impact translates to more than 7C total. That’s extremely close to a +ve feedback coefficient >1 which means runaway temperature rise without end – the Venus scenario.
But we know that world has been far warmer in the past than the measly 1C direct impact predicted from doubling CO2 to 560 ppm and we are nowhere near the 560 ppm level as yet) so, as so many others have pointed out, why didn’t the world run away to Venus situation long ago. Forget about whether CO2 was high or low at the time, the warmer temperature should have been enough to result in runaway.
This research fails even the most basic common sense test.
Another point (somewhat off topic) which really bugs me is when “scientists” claim a sudden new “discontinuous” effect to explain an unexpected change. In this case, the rise in CO2 apparently slowed down over the last 15 years and a recent post suggested its because the plants had been taking up more of the CO2 as shown by the global greening. Don’t these people understand the first thing about feedback systems. If the rising CO2 was triggering faster plant growth (which I very strongly suspect is true) then that would have been happening on a continuous basis right since he time CO2 had started to rise and it would have been reducing the rate of CO2 though all that time, it would not have suddenly and mysteriously only started in the early 21st century. If one looks for a cause of a sudden change in slope of CO2 vs time it HAS to be something that changed at about the same time and plant growth does not fit. On the other hand temperature does, the pause is well documented and talked about and dates from very much the same time. But that suggests the rise in CO2 is driven – at least in part – by temperature, as the temperature rise slows so does the rate of rise of CO2. How inconvenient, yet another piece of evidence suggesting the rise in CO2 is a result of the rise of temperature not the other way round (look at the remarkable fit between dCO2/dtime and temperature). But such a finding would call into question whether man is even responsible for most of the rise in CO2 a completely unacceptable idea even to contemplate by warmists so another reason has to be found even if it is utterly implausible.
CMIP5 global temp mean projections (based on ECS=3C~4.5C) already exceed reality (UAH6.0) by over 2 standard deviations for 20 years, which is more than sufficient disparity and duration to disconfirm the CAGW ho-x with high confidence.
In 5~7 years, the disparity will VERY likely exceed 3+ standard deviations for 25+ years,which is the realm of absurdity.
Trump needs to appoint a good Science Advisor and shutdown this silly disconfirmed CAGW ho-x once and for all..
We’re wasting $100’s of billions/yr on compliance costs of stupid CO2 regulations, wind/solar subsidies, CAGW research grants, insanely expensive/inefficient grid-level wind/solar plants, etc.
“Elections have consequences”, as Obama said….it works both ways…
CMIP5 based climate models have been invalidated so anything based on CMIP5 is at the very least, suspect. In their first report, the IPCC published a wide range of possible values for the climate sensitivity of CO2 In their last report the IPCC published the exact same values. So after more than two decades of effort the IPCC has learned nothing that would allow them to decrease their range of guesses one iota. The IPCC is refusing to acknowledge the work of many estimated that the climate sensitivity of CO2 is much lower than the ranges of guesses made by the IPCC for fear of losing their funding.
The last interglacial period was warmer than this one with higher sea levels and more ice cap melting to include a greater amount of so called greenhouse gases in the atmosphere yet that interglacial period ended with the start of the last ice age and life continued to evolve.
There is no real evidence that CO2 has any effect on climate. There is no such evidence in the paleoclimate record. There is plenty of scientific reasoning to support the idea that the climate sensitivity of CO2 is really zero. If CO2 really effected then one would expect that the increase over the past 30 years would have caused at least a measurable increase in the dry lapse rate in the troposphere but such has not happened.
You mean… it’s worse… (gasp) — than we thought??!!
Based on simply a review of the abstract, this paper is a thoroughgoing embarrassment to contemporary science, and a disgrace to the peer-reviewed journal that chose to publish such utter drivel. Beyond this, it is an eloquent testimonial to the rabbit-hole thinking that engulfs the minds of people who are drunk on the potentialities of pure theory unconstrained by any reference to the reality of hard data from the Earth system.