As mentioned in our WUWT story earlier today Increased CO2 Emissions Will Delay Next Ice Age the official press release is now out at Eurekalert and published below. I can hear the wailing and gnashing of teeth already. Bottom line, you can manage a hot summer, but you can’t get out of the way of tons of ice. Unfortunately, the authors find a way to make this out to be bad news, by suggesting Antarctica is melting. So far, we’ve seen no evidence of that. In fact Antarctic Sea Ice is trending upwards in the past 30 years:
Graph source: Cryosphere Today
From the University of Florida
Global warming caused by greenhouse gases delays natural patterns of glaciation, researchers say
GAINESVILLE, Fla. — Unprecedented levels of greenhouse gases in the Earth’s atmosphere are disrupting normal patterns of glaciation, according to a study co-authored by a University of Florida researcher and published online Jan. 8 in Nature Geoscience.
The Earth’s current warm period that began about 11,000 years ago should give way to another ice age within about 1,500 years, according to accepted astronomical models. However, current levels of carbon dioxide are trapping too much heat in the atmosphere to allow the Earth to cool as it has in its prehistoric past in response to changes in Earth’s orbital pattern. The research team, a collaboration among University College London, University of Cambridge and UF, said their data indicate that the next ice age will likely be delayed by tens of thousands of years.
That may sound like good news, but it probably isn’t, said Jim Channell, distinguished professor of geology at UF and co-author.
“Ice sheets like those in western Antarctica are already destabilized by global warming,” said Channell. “When they eventually slough off and become a part of the ocean’s volume, it will have a dramatic effect on sea level.” Ice sheets will continue to melt until the next phase of cooling begins in earnest.
The study looks at the prehistoric climate-change drivers of the past to project the onset of the next ice age. Using astronomical models that show Earth’s orbital pattern with all of its fluctuations and wobbles over the last several million years, astronomers can calculate the amount of solar heat that has reached the Earth’s atmosphere during past glacial and interglacial periods.
“We know from past records that Earth’s orbital characteristics during our present interglacial period are a dead ringer for orbital characteristics in an interglacial period 780,000 years ago,” said Channell. The pattern suggests that our current period of warmth should be ending within about 1,500 years.
However, there is a much higher concentration of greenhouse gases trapping the sun’s heat in the Earth’s atmosphere now than there was in at least the last several million years, he said. So the cooling that would naturally occur due to changes in the Earth’s orbital characteristics are unable to turn the temperature tide.
Over the past million years, the Earth’s carbon dioxide levels, as recorded in ice core samples, have never reached more than 280 parts per million in the atmosphere. “We are now at 390 parts per million,” Channell said. The sudden spike has occurred in the last 150 years.
For millions of years, carbon dioxide levels have ebbed and flowed between ice ages. Orbital patterns initiate periods of warming that cause ocean circulation to change. The changes cause carbon dioxide-rich water in the deep ocean to well up toward the surface where the carbon dioxide is released as a gas back into the atmosphere. The increase in atmospheric carbon dioxide then drives further warming and eventually the orbital pattern shifts again and decreases the amount of solar heat that reaches the Earth.
“The problem is that now we have added to the total amount of CO2 cycling through the system by burning fossil fuels,” said Channell. “The cooling forces can’t keep up.”
Channell said that the study, funded by the National Science Foundation in the U.S, and the Research Council of Norway and the Natural Environment Research Council in the United Kingdom, brings to the forefront the importance of atmospheric carbon dioxide because it shows the dramatic effect that it is having on a natural cycle that has controlled our Earth’s climate for millions of years.
“We haven’t seen this high concentration of greenhouse gases in the atmosphere for several million years,” Channell said. “All bets are off.”
OK, so let me get this straight – On the one hand we can live in a world with more CO2 where plants grow better and temperatures are somewhat higher, although perhaps some areas may or may not be a bit too hot for comfort. On the other hand we can live in a world with less CO2 where plants grow poorly and temperatures are considerably lower, with the UK and large parts of North America are under thousands of metres of ice. Now let me think…….
Honestly, how can anyone get excited about this? Just compare man’s technological capability of 1500 years ago with today. Now project that increase forwards another 1500 years. This is like hearing about a traffic holdup on a road you’re going to drive on next week – by the time you get there, the problem will have been solved – if there was even a problem in the first place!
Let’s just assume that Chen et al., 2009 is correct: Antarctica is losing 190 ± 77 Gt of ice mass per year. Let’s also assume that 1 Gt of ice = 1 km^3 of ice.
One of the things about using GRACE measurements to calculate changes in ice mass is that you have to adjust the data for something called “Post Glacial Rebound” (PGR). I don’t have a full-text copy of Chen’s paper handy; but I do have a copy of Velicogna & Wahr, 2006. They determined that the PGR was 192 ± 79 km3/year. The net ice loss equals the measured ice loss minus the PGR. So, Chen’s net ice loss basically equals the PGR. GRACE is measuring no change in Antarctic ice mass.
But, just for fun. Let’s assume that Antarctica is losing 190 Gt of ice mass per year. 190 Gt sounds like a really big number, doesn’t it?
360 Gt of ice melt will yield 1 mm of sea level rise. 190 Gt is good for ~0.5 mm/yr of sea level rise.
The volume of ice in the Antarctic ice cap is ~30,000,000 km3. 190 Gt is 0.0006% of 30 million km3. GRACE is measuring no net change in the ice mass; yet a 0.0006% annual change is being calculated from the PGR adjustment.
At 0.0006% per year, Antarctica will have lost 0.06% of its ice mass by the end of this century! And sea level will have risen by… (drum roll)… 46 millimeters!!!… Almost 2 inches!!!
“Over the past million years, the Earth’s carbon dioxide levels, as recorded in ice core samples, have never reached more than 280 parts per million in the atmosphere. “We are now at 390 parts per million,” Channell said. The sudden spike has occurred in the last 150 years.”
A recent paper about ice cores at Dome A in Antarctica
http://www.igsoc.org/journal/current/207/j11J138.pdf
suggests that annual ice accumulation there, which is reputedly one of the slowest accumulating locations on the continent, is about 1 inch/yr
” Using two known volcanic stratigraphic markers, the mean accumulation rate during the period AD 1260–1964 is found to be 23.2 mm w.e. a –1, consistent with the previously reported accumulation rate at Dome A.”
The length of time since there has been a significant continental melting opportunity in Antarctica is the subject of a great deal of speculation, but from what I’ve seen the estimates range from 1-3 million years. taking the lowball number of 1 million and 1inch/ year, since it is given in water equivalent the greater volume of ice should cover for compression effects and any long term variations, you end up with a figure for ice accumulation without opportunity of melting of nearly 16 miles depth. The CW is that the current icecap is 1 mile+/- deep across most all of the continent. This suggests that about 95% of ice that has accumulated over the last million years is now gone, most probably by the same manner which it is leaving now i. e. by extruding flows out to coastal ice sheets. My question is this, disregarding for the moment the multitude of possible problems with extracting accurate CO2 information from ice cores, how do you assume you can capture a million years of data from cores which can’t possibly cover that timescale? I would point out that I’ve seen estimated accumulation rates for other areas that range up to 6 inches/year. Combine those with the high end 3 million year duration and you are talking about hundreds of miles of ice that may have come and gone
“Ice sheets like those in western Antarctica are already destabilized by global warming,” said Channell. “When they eventually slough off and become a part of the ocean’s volume, it will have a dramatic effect on sea level.” Ice sheets will continue to melt until the next phase of cooling begins in earnest.
Of course, melting sea ice changes sea level by how much, exactly? Would that be “zero”?
It would.
Or are they suggesting that land ice in Antarctica is melting? Don’t be absurd!
rgb
John Marshall says:
January 9, 2012 at 2:15 am
And during the Ordovicean there was a severe ice age. Agreed, although I thought the figure was 4000-4200 ppm CO2.
In the late Carboniferous 350 ppm CO2 didn’t stop an ice age starting. During the later Jurassic there was an Antarctic ice cap (for 13 million years) despite over 2,000 ppm CO2.
Our current Antarctic ice cap formed over 30 million years ago, when there was 1000 ppm CO2.
We slid into this current 2-3 million really cold time from 450-500 ppm CO2.
The chances of this claim being true can be calculated by totalling the numbers of holidaymakers going to the Mediterranean or the Caribbean and dividing it into the number choosing to holiday in Svalbard or Baffin Island. Multiply by 100 to get a percentage.
“but I do have a copy of Velicogna & Wahr, 2006. They determined that the PGR was 192 ± 79 km3/year. The net ice loss equals the measured ice loss minus the PGR. So, Chen’s net ice loss basically equals the PGR. GRACE is measuring no change in Antarctic ice mass.”
The abstract of that paper:
(Measurements of Time-Variable Gravity Show Mass Loss in Antarctica)
“Using measurements of time-variable gravity from the Gravity Recovery and Climate Experiment satellites, we determined mass variations of the Antarctic ice sheet during 2002–2005. We found that the mass of the ice sheet decreased significantly, at a rate of 152 ± 80 cubic kilometers of ice per year, which is equivalent to 0.4 ± 0.2 millimeters of global sea-level rise per year. Most of this mass loss came from the West Antarctic Ice Sheet.”
Velicogna had a paper in 2009 which confirmed that Antarctica was losing ice:
(Increasing rates of ice mass loss from the Greenland and Antarctic ice sheets revealed by GRACE)
“We use monthly measurements of time-variable gravity from the GRACE (Gravity Recovery and Climate Experiment) satellite gravity mission to determine the ice mass-loss for the Greenland and Antarctic Ice Sheets during the period between April 2002 and February 2009. We find that during this time period the mass loss of the ice sheets is not a constant, but accelerating with time, i.e., that the GRACE observations are better represented by a quadratic trend than by a linear one, implying that the ice sheets contribution to sea level becomes larger with time.”
From the conclusion:
“We showed that a detailed analysis of the GRACE time series over the time period 2002–2009 unambiguously reveals an increase in mass loss from both ice sheets. The combined contribution of Greenland and Antarctica to global sea level rise is accelerating at a rate of 56 ± 17 Gt/yr2 during April 2002–February 2009, which corresponds to an equivalent acceleration in sea level rise of 0.17 ± 0.05 mm/yr2 during this time. This large acceleration explains a large share of the different GRACE estimates of ice sheet mass loss published in recent years. It also illustrates that the two ice sheets play an important role in the total contribution to sea level at present, and that contribution is continuously and rapidly growing.”
http://www.agu.org/pubs/crossref/2009/2009GL040222.shtml
“Of course, melting sea ice changes sea level by how much, exactly? Would that be “zero”?
It would.
Or are they suggesting that land ice in Antarctica is melting? Don’t be absurd!”
http://wattsupwiththat.com/2012/01/08/new-paper-agw-may-save-us-from-the-next-ice-age/#comment-858758
Yes, that is what “ice sheet” means. And land ice most definitely is melting in Antarctica. Scientists are well aware of the difference between sea ice and land ice sheets, and how each affects sea level rise.
The authors are talking about the ice sheet, not the sea ice, and the ice sheet is melting. (I’ve read speculation that the slight increase in sea ice may be a result of more land ice sliding off the continent).
Robert Murphy says:
January 9, 2012 at 11:50 am
“The combined contribution of Greenland and Antarctica to global sea level rise is accelerating at a rate of 56 ± 17 Gt/yr2 during April 2002–February 2009, which corresponds to an equivalent acceleration in sea level rise of 0.17 ± 0.05 mm/yr2 during this time. This large acceleration explains a large share of the different GRACE estimates of ice sheet mass loss published in recent years. It also illustrates that the two ice sheets play an important role in the total contribution to sea level at present, and that contribution is continuously and rapidly growing.””
You seem to share with these folks a rather curious conception of what a “large acceleration” and ” rapidly growing” means. ” 0.17 ± 0.05 mm/yr”? That’s a little over a half an inch by the turn of the century. Very scary!
Aside from that the whole notion that we can know GMSL to millimeter or tenth of a millimeter accuracy is a logical impossibility. Leaving out the technical problems of satellite altimetry. GMSL is a measurement of height. To measure a height you require a fixed reference to base your measurements from. There is nothing on the planet whose position is known or fixed at the millimeter level over any timescale. The current data are anomalies calculated from variations relative to the geoid and the reference ellipsoid. Both are entirely imaginary concepts which bear scant relation to the actual reality of the planet. For most of the satellite record they used a fixed model of the geoid in order to try and maintain data consistency. With the advent of the GRACE and GOCE sats it was discovered that their model, which is based on variations in the planet’s gravitation strength, was significantly deficient. For the latest data they have revised the geoid model based on that new information. which is a step in the right direction, but in doing so they have made the current data apples to oranges relative to the old data because no similar data exist to provide similar corrections to the the pre GRACE measurements.
Did you miss the PGR bit?
The actual GRACE measurements in V&W 2006 showed a net gain in ice volume.
+40 km3/yr – PGR (+192 km3/yr) = -152 km3/yr
The PGR is estimated from various models. It is not measured…
GRACE has been flying for less than a decade. It has measured no ice loss. The ice loss has consistently consisted of PGR adjustment.
If the PGR adjustment is correct, the ice loss is insignificant.
This paragraph is a pretty good clue that the PGR is wrong…
Sea level rise did not accelerate from 2002-2009. It decelerated…
Global Mean Sea Level Time Series (seasonal signals removed)
Sea level was rising at a rate of 3.3 mm/yr from 1992-2001. Since GRACE has been flying (2002), sea level has been rising at 2.2 mm/yr. Sea level hasn’t risen at all since January 2009.
“GRACE has been flying for less than a decade. It has measured no ice loss. The ice loss has consistently consisted of PGR adjustment.”
Not according to the paper you linked to. They say “that the mass of the ice sheet decreased significantly, at a rate of 152 +/- 80 cubic kilometers of ice per year, which is equivalent to 0.4 +/- 0.2 millimeters of global sea-level rise per year.” That’s *after* taking into account the PGR, not before; if you didn’t take into account PGR, the number for ice loss would be an *additional* 192 ± 79 km3/year, in other words over 340 km3/year. The 2009 paper conformed this. You are seriously misunderstanding the paper.
“Sea level rise did not accelerate from 2002-2009. It decelerated…”
The papers were talking about the acceleration of the contribution of the melting ice sheets to sea level rise (which, btw, is not taken into account by the IPCC in their estimates), *not* of the acceleration of global sea level rise during that time frame. Apples and oranges.
Robert Murphy says:
January 9, 2012 at 6:07 am
“You do realize that there are dozens and dozens of CO2 monitors all over the world, not just the one at Mauna Loa, and that they all agree to within a few ppmv? In fact, the one that has been around the longest is in fact in Antarctica. Mauna Loa is the one cited because while it started a few years later, it has the longest *continuous* record, while the one in Antarctica had a few years of no data decades ago. They show the same increase in CO2.”
True Robert.
BUT there is more to this puzzle. The following is from memory but is reasonably accurate.
The northern CO2 measuring station at Barrow, Alaska has a seasonal amplitude of almost 20ppm whereas the one at the South Pole has almost no seasonal amplitude.
The rise in average atmospheric CO2 is about 2ppm/year, or about one-tenth of the seasonal amplitude at Barrow.
Natural CO2 flux is therefore many times greater than the relatively small component from humanmade emissions.
Furthermore the material balances don’t work very well, and are probably based on faulty assumptions.
Finally, CO2 lags temperature at all measured time scales.
Perhaps this leads t the conclusion that temperature drives CO2, not the reverse.
There is another mystery about CO2 lifetimes. It is always assumed that CO2 emissions by man will hang around for upwards of 100 years. So even if we stopped all emissions tomorrow CO2 levels would remain above 390 ppm for a hundred years. You also hear from people like Hansen that warming “inertia” is already stored in the oceans and temperatures would continue to rise even curbing CO2 levels. However, the nuclear bomb tests in the 60’s produced large amounts of C14 which left a signature in atmospheric CO2. This allowed accurate measurements of the CO2 lifetimes which work out at between a minimum of 5 years and a maximum of 15 years.
So a single CO2 molecule remains in the atmosphere for only about 10 years. The only argument that can still be validly made is that somehow the Carbon Cycle has been knocked out of equilibrium and will take a hundred years to recover. However, the large seasonal changes changes in CO2 would appear to support a short lifetime and also a resilient carbon cycle.
That’s what I said.
GRACE measured a 40 km3/yr ice volume increase from 2002-2005. V&W modeled at 192 km3/yr PGR-induced apparent ice volume increase.
40-192 = 152.
The entire 152 km3/yr ice volume decrease was due to the PGR adjustemt.
It’s more like Galas and Macintoshes or Tangerines and Oranges.
The ice melt contribution to sea level rise supposedly accelerated at rate of 0.17 ± 0.05 mm/yr2 from April 2002 to February 2009, while the actual rate of sea level rise was decelerating…
2011_rel4: Global Mean Sea Level Time Series (seasonal signals removed) Before and After April 2002
Math typo… 40-192 = -152
I made a mistake above; the PGR was indeed subtracted. That doesn’t mean the PGR is a figment as you suggest however. You’re hand-waving away data you don’t like arbitrarily. If it’s contribution was in the opposite direction, you would have no issue with the use of models.
“The ice melt contribution to sea level rise supposedly accelerated at rate of 0.17 ± 0.05 mm/yr2 from April 2002 to February 2009, while the actual rate of sea level rise was decelerating”
Since the ice melt contribution to sea level rise is very small, there is no inconsistency. Most of the increase so far has been from thermal expansion. Again, you are talking about two different things.
The ice melt contribution is supposedly ~0.4 to 0.5 mm/yr. That would be about 20% of the rate since 2002.
Steric sea level rise would have to be deccelerating more than 0.17 mm/yr2 at a time when the ice melt sea level rise is accelerating by 0.17 mm/yr2 for the overall sea level rise to have deccelerated from 3.35 to 2.23 mm/yr between 2002 and 2011.
I’m not suggesting PGR is a figment. We know there is some positive PGR in Antarctica. I’m simply pointing out that the actual GRACE measurements show no net Antarctic ice loss.
Actual measurements of Antarctic sea ice show it to be increasing, steric sea level rise is decelerating… Yet Antarctic ice melt is accelerating – I don’t think so.
http://www.multiupload.com/C2VGD3KF1X
‘their data indicate that the next ice age will likely be delayed by tens of thousands of years….
“Ice sheets like those in western Antarctica are already destabilized by global warming,” said Channell. “When they eventually slough off and become a part of the ocean’s volume, it will have a dramatic effect on sea level.” ‘
So either we freeze to death in an ice age or we drown under rising seas.
We’re doomed.
The interglacial taken in this paper as the closest match to the present interglacial (without increasing CO2) is MIS 19c, 780,000 yrs ago. What else happened 780,000 yrs ago? The orientation of Earth’s magnetic field flipped. Also over time the relative importance of the obliquity, precession and orbital eccentricity components in the Milankovitch cycles has gradually changed. In trying to predict the onset of the next glacial period, the only Milankovitch cycle that counts is the one we’re in, not trying to say (without increasing CO2) we would be repeating some previous interglacial long in the past.
I am not biting. It is like admitting that CO2 causes global warming. On the other hand, don’t the ice ages usually start right about the time that CO2 in the atmosphere is near a maximum?
Robert Murphy says:
January 9, 2012 at 11:53 am
“Scientists are well aware of the difference between sea ice and land ice sheets, and how each affects sea level rise.”
Is this one of the scientists you are referring to? ;
http://www.climatechangefacts.info/ClimateChangeDocuments/NilsAxelMornerinterview.pdf
Next Ice Age glaciation delayed? Thank goodness (or SUV’s if that’s your pet causal agency).
Warmer Is Better. Fight The Ice.
Wow – the MSM has woken up to the issue of the inevitable forthcoming interglacial – glacial transition. This is remarkable in its own right.
This new research contradicts the previous orthodoxy – which is quoted periodically on this site – that we are currently similar to the 400,000 year ago interglacial and – in a paper by Ruddiman et al. – it is asserted that due to our current weak node of eccentricity oscillation, our interglacial will somehow fantastically continue for another 50,000 years (this effectively would mean that the current glacial epoch has ended.) It is good to see this nonsense brushed aside by more serious scholarship from Cambridge University.
The Cambridge-led team has now identified the most similar interglacial, with respect to Milankovich parameters, to be not 400kYa but 780 kYa. Further, they point to one feature presaging an end-of-interglacial as a “see-sawing” between warming/cooling between the northern and southern hemispheres. The southern hemisphere sea ice anomaly figure at the top of this post points to exactly this phenomenon – in the last 30 years as Arctic sea ice has shrunk, Antarctic sea ice has grown. This reciprocity has now been recognised as diagnostic of a terminating interglacial.
The paper should be read as a serious and important advance in understanding of the imminent end of the current interglacial, and the embarrasingly weak politically-correct epilogue of “but increasing CO2 means that it wont happen really” should be ignored – the authors themselves likely do not even believe it, they just needed it to be published.