Climate change will shake the Earth
A changing climate isn't just about floods, droughts and heatwaves. It brings erupting volcanoes and catastrophic earthquakes too
The idea that a changing climate can persuade the ground to shake, volcanoes to rumble and tsunamis to crash on to unsuspecting coastlines seems, at first, to be bordering on the insane. How can what happens in the thin envelope of gas that shrouds and protects our world possibly influence the potentially Earth-shattering processes that operate deep beneath the surface? The fact that it does reflects a failure of our imagination and a limited understanding of the manner in which the different physical components of our planet – the atmosphere, the oceans, and the solid Earth, or geosphere – intertwine and interact.
So what – geologically speaking – can we look forward to if we continue to pump out greenhouse gases at the current hell-for-leather rate? With resulting global average temperatures likely to be several degrees higher by this century's end, we could almost certainly say an eventual goodbye to the Greenland ice sheet, and probably that covering West Antarctica too, committing us – ultimately – to a 10-metre or more hike in sea levels.
GPS measurements reveal that the crust beneath the Greenland ice sheet is already rebounding in response to rapid melting, providing the potential – according to researchers – for future earthquakes, as faults beneath the ice are relieved of their confining load. The possibility exists that these could trigger submarine landslides spawning tsunamis capable of threatening North Atlantic coastlines. Eastern Iceland is bouncing back too as its Vatnajökull ice cap fades away. When and if it vanishes entirely, new research predicts a lively response from the volcanoes currently residing beneath. A dramatic elevation in landslide activity would be inevitable in the Andes, Himalayas, European Alps and elsewhere, as the ice and permafrost that sustains many mountain faces melts and thaws.
Across the world, as sea levels climb remorselessly, the load-related bending of the crust around the margins of the ocean basins might – in time – act to sufficiently "unclamp" coastal faults such as California's San Andreas, allowing them to move more easily; at the same time acting to squeeze magma out of susceptible volcanoes that are primed and ready to blow.Read the full article here.
I wonder if there are any people out there who can comment on this in an informed way? And, will this kind of new research McGuire refers to be included in the next IPCC report?
Posts
19 comments:
http://www.nature.com/news/2009/090917/full/news.2009.926.html
SCIENTIFIC MARKETING
Some people may just laugh, others will rather be wondering about assumptions like "global average temperatures likely to be several degrees higher by this century's end" or "10-metre or more hike in sea levels" - while temperatures and sea levels are stagnating in the last years.
But these numbers are not of McGuire's business. As a volcanologist he's taking them from the worst climate scenarios he could find.
Instead of laughing about his ideas, one should admit that he's quite clever - just because the next earthquake will give the cause a proof - and if there will be two or three in a row, the hypothesis will nearly get evidence.
The chances that there will be some earthquakes in the future - even this year alone - are quite good. So are the chances of Prof. McGuire's hypothesis to find public interest. There are always earthquakes somewhere on this globe.
We had all kind of predictions based on attributional studies: more storms, wars, climate refugees, Malaria, heat waves, floods etc.
After all it must have been difficult to identify a completely new one.
Prof. Guire is trying to enter the outgoing train of global warming fears. He's a little late but he's far from being the only one ...
http://wattsupwiththat.com/2012/02/23/they-shrink-horses-dont-they
V. Lenzer
All one has to consider in terms of being "science" is the number of "mights" and "coulds" and "mays", like so many other scaremongering articles. It's not science, it's reading tea leaves.
William Teach
I noted that too. But McGuire refers to "new research" so I wondered what that might be.
Comment 1 linked to an article in Nature which quotes McGuire and some work being done by others. But there is a lot of guesswork going on. And the Nature article was published in Sept 2009, in the run up to COP15/Copenhagen summit.
So why this this super-alarming article now? Maybe a PR move to get this problem included in the next IPCC report? The above Nature article closes with a quote from McGuire who complains that the IPCC so far has overlooked the problem:
"The IPCC [Intergovernmental Panel on Climate Change] hasn't addressed these kinds of hazard," he says. "You have a better chance of coping with any kind of hazard if you know it's happening," he adds. "Climate change is not just the atmosphere and hydrosphere; it's the geosphere as well."
First time I saw the article in the Guardian I didn't read it because of the "shaky" headline. Having done it now I must admit it's not so bad.
Perhaps it helps if one imagines, it's an article primerily about geology, not climate science. And remember: Geologists think in larger timescales than we (and IPCC reports) are used to.
Andreas
Reiner, I recall that a NASA scientist argued that climate change will make us more vulnerable to attacks by extra terrestrials, so why not volcanoes? http://www.guardian.co.uk/science/2011/aug/18/aliens-destroy-humanity-protect-civilisations
Pielke jr. had a post in early Jan on the frequencies and magnitude of earthquakes since 1900.
http://rogerpielkejr.blogspot.com/2012/01/are-big-earthquakes-becoming-more.html
Maybe this may serve as background info.
RainerS
thanks for this pointer. Roger links to a PNAS paper which points out that we do see more violent (>9 magnitude) earthquakes recently which would indicate a clustering of events. However,
"These observations imply that global earthquake clustering, if
it has a physical explanation, is more analogous to seismic swarms
than to main shock–aftershock sequences. Swarms are spatially
compact clusters of events that occur for a limited time and
typically do not begin with their largest event. They are difficult
to explain with standard earthquake-to-earthquake triggering
models and are often ascribed to slow slip or fluid flow near
the swarm site (e.g., refs. 26 and 27); i.e., there is an underlying
physical driving mechanism. But no physical mechanism has been
proposed to explain possible global seismicity swarms that is
physically plausible and that would not be detected in other observations.
Although global cycles of earthquake energy release
have been hypothesized (2, 28), there is as yet no evidence to support
these ideas, other than apparent changes in seismicity rate,
which, as we have shown here and Michael (19) has shown, are
not statistically significant."
BTW, no mention is made of McGuire's work.
Andreas
The problem is that McGuire does not even mention a timescale.
Here's Dave Petley of the Institute of Hazard, Risk and Resilience commenting on an earlier outbreak of McGuire/Guardian hyperbole:
http://www.landslideblog.org/2009/09/oh-dear-more-scientific-hyperbole-about.html
The short version: some truth, much sensationalism, not helpful.
(For really nutty hyperbole about this sort of thing, look out for Veli Albert Kallio, who believes that giant earthquakes are already being triggered by the extra mass of water from melting ice sheets massaging the ocean floor like a baker kneading dough.)
''resulting global average temperatures likely to be several degrees higher by this century's end, we could almost certainly say an eventual goodbye to the Greenland ice sheet, and probably that covering West Antarctica too, committing us – ultimately – to a 10-metre or more hike in sea levels.'
There are no scenarios that foresee a sea-level rise of 10 meters in this century. Actually, there are published papers that show that a rise of 2 meters in this century would be highly unlikely, and can be almost surely be ruled out.
The most recent research based on models of the dynamical and thermodynamical response of the polar ice sheets to the expected 21st century warming rather indicate a sea-level rise by 2100 below 70 cm
At the present rate of melting, the Greenland ice sheet will disappear in about 15000 (fifteen thousand) years
The article by McGuire is at odds with every piece of research on future sea-level projections
Thanks Eduardo. I did not dare to make such a statement but cannot find a reason to disagree...
"The article by McGuire is at odds with every piece of research on future sea-level projections."
This poses an interesting question, especially to those keen to defend "the science" of the climate debate:
Would McGuire's piece be an instance of "anti-science", to use a term widely employed by some climate science activists? ;-))
Or would that be impossible by definition, because he is on the "right side"?
Eduardo: 'There are no scenarios that foresee a sea-level rise of 10 meters in this century.'
Well, McGuire did insert an 'ultimately' in that sentence.
(His comparing the world to a 'soup kitchen' is intriguing. In ethics land, do all 7 billion of us live on unearned emergency hand-outs from Mother Nature?)
@ Eduardo, Reiner
"resulting global average temperatures likely to be several degrees higher by this century's end, we could almost certainly say an eventual goodbye to the Greenland ice sheet, and probably that covering West Antarctica too, committing us – ultimately – to a 10-metre or more hike in sea levels."
I've been reading the same sentence, but understood it quite different (see my #5). In my opinion this sentence shows implicitly, that McGuire refers to geological timescales, millenia (also his predictions of "monster earthquakes etc.).
I regard the article as an attempt to make some PR for the author's research. PR = more fundings, who knows? There were times where using the word "nanotechnologie" in a proposal guarenteed good funding, perhaps it will work with "climate change", too ;-)
Andreas
@ 12,13
I cannot know for sure what McGuire meant exactly. Perhaps he was a bit unfortunate in the phrasing. But even adopting Andreas' point of view, I would understand that the increasing in temperature of a few degrees by 2100 already implies the demise of the Greenland ice sheet. This is not correct either. If the temperature rise is caped at say 2 degrees in 2100 and does not increase further, the Greenland ice sheet would probably not disappear either. For instance, the last interglacial about 120 thousand years ago was about 2 degrees warmer than the present and the Greenland ice-sheet did not disappear.
But maybe he meant still something else
@ Eduardo
To be clear: I think, the article is bad. If we here at Klimazwiebel are confused about it, it's hardly a help in public debate and volcanoes and earth quakes are not at all climate change impacts public should be afraid of.
Nevertheless I think we should be fair. Assuming the author thinks of a 10m sea level rise in 2100 sounds like assuming the author being an idiot.
In your last comment you did refer to a 2°C cap. Did you miss, that McGuire assumes a business-as-usual scenario?
So what – geologically speaking – can we look forward to if we continue to pump out greenhouse gases at the current hell-for-leather rate?
I looked at chapter 10 of AR4, WG1 and agree, that a 10m rise is not supported by the IPCC also for a BAU scenario, but I know rather little about newer research.
What's your opinion about the development of Greenland's ice sheets for a global warming of about 3 - 6°C according to a BAU scenario (plus arctic amplification)?
Andreas
Andreas
@ 15
Andreas,
BAU as scenario is only defined until 2100 (BtW, BAU is a bit outdated. It was used in the 3rd IPCC report. The 4th used the SRES scenarios and the 5th is using the RCP scenarios (Representative Concentrations Paths, just to avoid confusion if you consult other sources)
This means that beyond 2100 there are no commonly agreed concentration scenarios. There are simulations, but with concentrations paths more or less arbitrary chosen by the author of the simulations. The result showing the largest increase of global sea-level by year 2500, including all known contributions, is about 5.5 m of global sea-level rise. The Greenland contribution to the total is about 2.5 m. This means that the Greenland ice sheet would shrink by roughly 40%
One important question is how to design a scenario for year 2500. Imagine asking Christopher Columbus to make a prediction about the state of the world in year 2000.
@ Eduardo
Thanks, Eduardo, if I remember correctly the simulation with 5.5m sea level was given in ch.10 of AR4.
Please allow me one last question:
I'm a little bit confused, because I thought a better method than a simulation would be a look into the past. In ch. 6.3.2 (AR4) I find this:
The Mid-Pliocene (about 3.3 to 3.0 Ma) is the most recent time in Earth’s history when mean global temperatures were substantially warmer for a sustained period (estimated by GCMs to be about 2°C to 3°C above pre-industrial temperatures; Chandler et al., 1994; Sloan et al., 1996; Haywood et al., 2000; Jiang et al., 2005), providing an accessible example of a world that is similar in many respects to what models estimate could be the Earth of the late 21st century. The Pliocene is also recent enough that the continents and ocean basins had nearly reached their present geographic configuration. Taken together, the average of the warmest times during the middle Pliocene presents a view of the equilibrium state of a globally warmer world, in which atmospheric CO2 concentrations (estimated to be between 360 to 400 ppm) were likely higher than pre-industrial values (Raymo and Rau, 1992; Raymo et al., 1996), and in which geologic evidence and isotopes agree that sea level was at least 15 to 25 m above modern levels (Dowsett and Cronin, 1990; Shackleton et al., 1995), with correspondingly reduced ice sheets and lower continental aridity (Guo et al., 2004).
Because of this I would think, that a 15-25m sea level rise for longer timescales would be a realistic guess for a rather pessimistic CO2-scenario. Where is my mistake?
Andreas
@ 17
Andreas,
I thin we should consider the time scales involved, which for the polar ice sheets is very long. In a changing climate - either naturally or anthropologically, the polar ice sheets are seldom in equilibrium with the current global temperatures. For instance, you can drill a hole down the Greenland ice sheet and the temperature of the ice at a hundreds of meters below the surface will partially reflect the conditions at the surface a few thousand years ago. Actually the borehole temperature profiles, in the polar ice but also in the ground in ice-free regions, are used to reconstruct past surface temperatures.
Air temperatures at high latitudes in the Midholocene, around 6 thousand years ago, may have been 1 or 2 degrees warmer than now, and yet the Greenland Ice sheet did not melt away: this requires longer time.
I am not a glaciologist. There are still many unknowns in the dynamical behavior of polar ice sheets at long time scales, but probably 25 meters of sea-level rise is quite a long time into the future even with a strong increase of temperatures.
It is indeed a complex problem. For instance, in one of those multicentennial experiments I cited earlier , East Antarctica at first gains mass, because precipitation there increases rapidly with global temperatures, and only a few hundred years later the Antarctic mass balance turns negative. Precipitation is however not very well simulated in climate models,
Just one slight problem with McGuires' reasoning, which as a geologist he should know, and that is that crust deformation, or isostatic rebound, takes many centuries to even begin to happen, and similar time-scales to stop. Parts of N. Europe and Canada are still rising thousands of years after the ice sheets melted. The question is does he know, and has chosen to omit the "inconvenient truth", like so many alarmists?
I recall from several (at least) years ago reading that many geologists just ignore his scary scenarios.
The truth, but not the whole truth perhaps.
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