Guest post by David Middleton
Sea levels could rise far more rapidly than expected in coming decades, according to new research that reveals Antarctica’s vast ice cap is less stable than previously thought.
The UN’s climate science body had predicted up to a metre of sea level rise this century – but it did not anticipate any significant contribution from Antarctica, where increasing snowfall was expected to keep the ice sheet in balance.
According a study, published in the journal Nature, collapsing Antarctic ice sheets are expected to double sea-level rise to two metres by 2100, if carbon emissions are not cut.
Previously, only the passive melting of Antarctic ice by warmer air and seawater was considered but the new work added active processes, such as the disintegration of huge ice cliffs.
“This [doubling] could spell disaster for many low-lying cities,” said Prof Robert DeConto, at the University of Massachusetts Amherst, who led the work. He said that if global warming was not halted, the rate of sea-level rise would change from millimetres per year to centimetres a year. “At that point it becomes about retreat [from cities], not engineering of defences.”
[…]
I don’t know if Mr. Carrington has poor math, poor reading skills or is just inclined to hype his stories. The “study, published in the journal Nature,” is actually an interesting paper and the full text is available for reading, but not downloading. The authors devised a model which couples Antarctic ice loss to past sea level rises in the Pliocene and Pleistocene. They then used this model, coupled with “Representative Carbon Pathway (RCP)” scenarios to forecast future sea level rises.
DeConto and Pollard conclude that “Antarctica has the potential to contribute more than a metre of sea-level rise by 2100.”
Mr. Carrington apparently added this 1 meter to the IPCC’s 1 meter to come up with 2 meters. He even bastardized a quote from Dr. DeConto…
“This [doubling] could spell disaster for many low-lying cities.”
The word “doubling” is Carrington’s, not DeConto’s.
I don’t know if Mr. Carrington read the paper or not; however the authors never forecasted a sea level rise of 2 meters by 2100…
The IPCC sea level forecast for 2100 in RCP 8.5 with ice-sheet rapid dynamics is 0.74 m (0.52 to 0.98 m), not 1 meter. The Antarctic contribution is 0.04 m (-0.06 to 0.12).
If we go with the most likely, worst case RCP 8.5 scenarios…
IPCC – Antarctica = 0.70 m
DP 2016 Antarctica = 1.05 m
Sum =1.75 m
Under this scenario, the Antarctic contribution would actually more than double the IPCC’s forecast… But it would still be less than 2 m.
Now, let’s have a look at RCP 8.5…
This noachian deluge forecast is based on the assumption that the atmospheric CO2 concentration will rise to 1,120 ppm by 2100
Does anyone actually believe that humans could burn enough stuff over the next 84 years to drive CO2 levels up by 700 ppm above the current ~400 ppm? CO2 would have to rise by an average of 8.33 ppm per year over the remainder of the 21st century.
It appears that RCP 8.5 will turn Earth into Venus by 2100 AD.
But, what happens if I use real data?
Let’s assume that the atmospheric CO2 level will rise along an exponential trend line until 2100.
I get a CO2 level of 560 ppmv, in line with RCP 4.5… which leads to 0.53 (± 0.18) meters of sea level rise by 2100.
The only way sea level rise could approach the high end of the IPCC range is if it exponentially accelerates…
The rate from 2081-2100 would have to average 20 mm per year, twice that of the Holocene Transgression. This is only possible in bad science fiction movies in which Earth turns into Venus by 2100.
There simply is no data- or observation-driven reason to conclude that sea level will rise by more than 0.16 to 0.28 m (7-11 inches) during the 21st century under a realistic “business as usual” Representative Carbon Pathway.
Addendum
RCP 8.5 is even more batschist crazy then I had assumed…
IPCC forecast for 2100 + 0.74m
Observed 2000-2016 +.025m
We are 1/30th of the way there after 1/6 of the century.
LOLs. Just wait til that “hidden heat” hiding in the ocean deeps decides to come out.
Then you’ll be sorry!
“Oh Noes!!! Sea Level Rise to Double”
And this time we really, really, mean it.
..or else.
The paper claims that Antarctica “could contribute” a metre of sea level rise by 2050 … dear heavens, whatever these guys are smoking must be da kine …
Sea level rise is currently on the order of 2 mm/year. Suppose it started to accelerate today today at a constant rate, an exponential increase that will be continued for 84 years. In order to get to an additional metre of rise by 2100, the exponential increase in the rate must be 3.76% per year, a stupendous increase that leads to ludicrous sea level rise rates of over 40 mm/year by the year 2100. Riiiight …
Since they have nothing but their whiz-bang model to support this bizarre claim, I’m going to go back to real science and leave them to their fun.
w.
Funny how people like you and me can come to that conclusion using a spreadsheet, yet these “experts” cant, or wont, as they need to keep the lie going so their funding keeps going.
Let’s hope ice sheets know Excel.
Ah… But it’s such an “elegant” whiz-bang model… 😉
Willis: I am trying to engage Gavin with a bet. He stated 1 meter by 2100, and said it was quite likely. I offered 1000 to 10000, in trust of course. No nibble.
I then offered 5 mm/year RATE by 2050 would NOT be achieved. Crickets.
I did get a twitter response from someone else, who was willing to bet that Gavin would NOT take the bet. That does seem the safer bet.
The paper talks about the West Antarctica ice sheet collapsing. That event, if true, is unrelated to the level of sea rise occurring today. It’s more analogous to a dam bursting on a river – to look at the rise in river flow prior to the dam bursting will not give you any indication of the increase in water flow the bursting dam will cause.
The paper discusses a potential collapse of part of the WAIS in a hypothetical world in which Earth turns into Venus by the end of this century.
The authors assume that CO2 will rise to 900+ ppm by 2100 and that the ECS is >3°C. Both assumptions are so unrealistic, that they might as well be impossible.
This is the sort of thing Grauniad readers like to say in the comments sections of that lunatic rag “Humans will largely die off within 30 years and be extinct within 50 years”.
I suspect that^ one will be up for a Darwin award before long
The sea level rise in 2100 is worse than we thought it’s actually going to be 1000 metres and this time unlike any of the other times we really really really positively absolutely unrefutably 100 percent guarantee with 12.56745321 percent confidence that it will happen.
(Subject to change in our weekly updates)
I will get worried about sea level rise when I see any evidence here in Australia that there has been any noticeable rise in sea level since 1850. So far things are normal. What may be going on in the minds of the Warmistas, in the adjusted graphs and in the computer models is another matter.
I was filling up my car at the local gas station in southern Minnesota. The convenience store recently installed TVs in the gas pumps to entertain you and when I was almost done an info lady came on and referenced this study! All I could think of was all of the low information climate consumers now have this factoid stuck in their skulls along with the 97% consensus.
** I don’t know if Mr. Carrington has poor math, poor reading skills or is just inclined to hype his stories. **
In fact, Mr. Carrington has poor math, poor reading skills and is just inclined to hype his stories.
I sail often in a boat that costs more than … anyway I have no problem sailing off charts decades old…hell many charts rely on surveys from a century ago. Other than hazards to navigation not much changes. Certainly tides and seal levels are little changed decade to decade.And of course GBS is better, but I sailed for decades without.
I’m quite happy to accept the premise that accelerating anthropogenic global warming should cause an acceleration of ice sheet melting and therefore an acceleration of sea level rise rate.
Looking directly at the long-term coastal gauge charts it is quite clear that no such acceleration is occurring.
Especially not when also accounting for subsidence caused by drainage, and aquifer extraction.
Therefore, having accepted that first premise – I am hereby forced to reject the proposition that accelerating anthropogenic global warming exists at all.
My conclusion must be – that coastal gauges give us more accurate data than (for example) crappy bucket SSTs from the 19th century. That coastal gauge data is less prone to such problems as the need for multiple adjustments, equipment changes, UHI, relocation, changes in paint etc.
That’s enough for me. I’ll go with the coastal gauges.
The coastal gauge record has convinced me that everything else perceived must be based on poor data, anecdote, cherrypicking, bias, overcomplication of analysis and a strong and urgent desire to cash in on convincing the world that it is in peril.
Clearly nothing is melting at an accelerating rate and nothing is warming at an accelerating rate.
If it was – then it would be there in the coastal gauge records for all to see. And it isn’t.
Also, I notice that the authors of the above study have created some handy graphs which effectively “explain” why nothing of note will happen until around the point of their retirement.
Only then may we see the beginning of the catastrophic divergence from the trend of the last 100 years.
That leads me to suspect that they don’t expect to really see any changes either.
At least idiots such as Hansen and Erhlich had the conviction to make firm (but wrong) predictions of changes that would be witnessed in the near future.
This new breed of climatologist is a feeble wretch, who lacks conviction, but wants the attention all the same and creates myths about a post 2050 exponential apocalypse.
Go away, you tedious charlatans. We know what your game is.
Admit it. They are getting much smarter about their predictions, they are pushing the time out to way past retirement.
I think the fish will be down right pleased with this inaccurate model prediction .However,
the water front property owners in the scary global warming industry haven’t listed their
mansions yet so we must be OK for a year or two at least .
The conmen in the earth has a fever industry seemed to have learned to set their doom and gloom pronouncements to be really really devastating and effective after they retire . Can’t say they are stupid now .
Got to keep those government grants and contracts coming after all .
The 1970’s … earth is turning to an ice ball just had a more ominous tone and fear factor . Can we expect a return to that fertile ground now that scary global warming has lost it’s puff ? Climate change is that transition language from global warming to global cooling or what ever fear might be more saleable .
It’s about the money Honey and it always has been .
This reminds me of an earnest BBC environmental reporter who had managed to inveigle his way to the South Pole Base and earnestly told us how the ice was melting.due to climate change. He failed to realize that, within sight of the camera, on a bank of weather instruments, a gauge showed the outside air temperature ad -48 degrees! These clowns are so scientifically illiterate that they do not understand that the temperature needs to rise 49 degrees, not 2 degrees, which is supposed to be the tipping point, before the ice starts to melt.
They also seem to ignore that much of the sea ice at least, melts then re freezes annually. The long term trend is a small fraction of the annual change and so is subject to errors based on the seasonal change and annual change in weather.
The top post twice mentions Earth turning into Venus by 2100. I realize that the author doesn’t believe that, but the facts are that they are *very different planets, and it will be never be possible while Earth retains its strong magnetic fields, and retains its biomass and oceans, and maintains its rotation and distance from the Sun.
This is why the two planets cannot be directly compared: ..
1. Venus (like Mars) does not have a strong magnetic core. Therefore there aren’t any extensive magnetic fields to help protect the planet. Apparently, gases like hydrogen, helium, and oxygen ions, would have been swept away by the solar wind over very long periods of time, leaving the higher-mass molecules like carbon dioxide. (“Venus as a more Earth-like planet”, _Nature_ 450, Nov. 2007.)
2. Venus was left with a very dense atmosphere. It is more than 96% carbon dioxide.
3. The atmosphere’s pressure at the surface is 92 times more than Earth’s pressure.
4. Venus is considerably closer to the Sun, at about 0.72 of the distance from the Sun to the Earth.
5. The equator rotates at 6.5 km/h or 4 mph. (The Earth’s is about 1,670 km/h or 1,040 mph). Therefore a Venus day is *very long! Venus takes 243 Earth days to rotate once.
6. Naturally given the above, Venus does not have biomass, or oceans, to absorb some of the CO2, and it does not have a carbon cycle to lock carbon back into the rocks.
I thought the sarcasm was so obvious that I didn’t need to explain that the Venus comments were sarcastic.
I understood that *you didn’t believe it, and were using sarcasm. .. But there are some people who actually do believe that it would be possible some time in the future for the Earth to turn into a Venus. So whenever I get a chance I like to list the facts, so that they would (hopefully) have one less doomsday scenario to worry about. … … In the three years before the infamous date of Dec. 21, 2012, I used to help mainly young people who went to the website forum at ‘2012hoax.org’ because they were convinced that the world would end on that date. I guess the habit of trying to help people like that is still with me!
The 50-year sea level trend at The Battery peaked around 1950 as did a few others I happened to check a while back. This data is calculated at sites with data going back sufficiently far. There are other sites that do not agree but they seem to have rising or falling land that skew the data. Ultimately war we seeks its own level, so eventually differing levels should even out.