Tag Archives: Jonathan Amos

Iceberg A68 cruising out to sea!

A68 calved in 2017, and edged very slowly up the coast.  In the last year, she has really picked up the pace, covering roughly 500 km in the last 13 months, which is about 50 meters / hr,  something like 1 / 3 mph.  Not bad for an island!

From [1]. Image credit: S.BEVAN/Swansea University

She is about to enter the open ocean, which will mean a lot more stress from wind and wave, and will probably lead to a big breakup.  Soon there will be a whole flock of smaller, but still very dangerous, bergs.

The BBC reports that there are two more large bergs splitting from Antarctic glaciers, part of what may be a speed up of the ice flows into the ocean.  If the big glaciers begin to move to the sea faster, shedding more bergs, this probably indicates a loss of ice mass on the continent, and eventually to rise in the sea level.

Glub!


  1. Jonathan Amos, World’s biggest iceberg makes a run for it, in BBC News – Science & Environment, February 5, 2020. https://www.bbc.com/news/science-environment-51389690

 

Greenland Ice Balance Study

The ice is melting everywhere, but nowhere is better documented than Greenland.  This isn’t even news any more.  The only question is how fast the ice is disappearing in different places.

Last year, an international team (the Ice sheet Mass Balance Inter-comparison Exercise (IMBIE)) reported estimates of the mass balance for Antarctic ice, based on models and satellite data from 1992.  The data show ice losses in some parts of Antarctica, and little change elsewhere.

This winter, the IMBIE team report a similar study of Greenland [2].  Greenland is smaller than Antarctica, and there is a lot more data coverage (at least below 83 degrees North).  The study indicates that Greenland has been losing ice over the whole period (1992-2017), and rate of loss appears to be accelerating.  This is certainly consistent with other observations and measurements from surface and aircraft.

The study finds that about half the losses are due to increased run off (melt water, due to warmer air temperatures) and half due to the acceleration of glaciers (due to warmer coastal waters).

The recent rate of melting corresponds to a rise in mean sea level of something like 7 mm per decade.  (When Greenland melts completely, that could be as much as 7 meters rise in mean sea level—glub!)

Combined with IMBIE’s earlier analysis of Antarctica, these studies show that melting is happening at the rate close to the “upper” estimate in the 2013 IPCC report.  This means that things are changing faster than expected in the earlier models.  Assuming that the new estimates hold up, that’s not good news.

Obviously, there are plenty of sources of uncertainty in both the data and the models. This team has taken great care to combine these dataset and deal with sources or error and uncertainty.  And in the case of Greenland, we have plenty of other data that point in the same general direction.  So it’s a pretty solid estimate, at least for now.

Ideally, there will be more and finer grained satellite observations coming in the next decade or two.  This new data should go far toward validating and refining these IMBIE estimates.


  1. Jonathan Amos, Climate change: Greenland ice melt ‘is accelerating’, in BBC News – Science & Environment. 2019. https://www.bbc.com/news/science-environment-48387030
  2. Andrew Shepherd, Erik Ivins, Eric Rignot, Ben Smith, Michiel van den Broeke, Isabella Velicogna, Pippa Whitehouse, Kate Briggs, Ian Joughin, Gerhard Krinner, Sophie Nowicki, Tony Payne, Ted Scambos, Nicole Schlegel, A. Geruo, Cécile Agosta, Andreas Ahlstrøm, Greg Babonis, Valentina R. Barletta, Anders A. Bjørk, Alejandro Blazquez, Jennifer Bonin, William Colgan, Beata Csatho, Richard Cullather, Marcus E. Engdahl, Denis Felikson, Xavier Fettweis, Rene Forsberg, Anna E. Hogg, Hubert Gallee, Alex Gardner, Lin Gilbert, Noel Gourmelen, Andreas Groh, Brian Gunter, Edward Hanna, Christopher Harig, Veit Helm, Alexander Horvath, Martin Horwath, Shfaqat Khan, Kristian K. Kjeldsen, Hannes Konrad, Peter L. Langen, Benoit Lecavalier, Bryant Loomis, Scott Luthcke, Malcolm McMillan, Daniele Melini, Sebastian Mernild, Yara Mohajerani, Philip Moore, Ruth Mottram, Jeremie Mouginot, Gorka Moyano, Alan Muir, Thomas Nagler, Grace Nield, Johan Nilsson, Brice Noël, Ines Otosaka, Mark E. Pattle, W. Richard Peltier, Nadège Pie, Roelof Rietbroek, Helmut Rott, Louise Sandberg Sørensen, Ingo Sasgen, Himanshu Save, Bernd Scheuchl, Ernst Schrama, Ludwig Schröder, Ki-Weon Seo, Sebastian B. Simonsen, Thomas Slater, Giorgio Spada, Tyler Sutterley, Matthieu Talpe, Lev Tarasov, Willem Jan van de Berg, Wouter van der Wal, Melchior van Wessem, Bramha Dutt Vishwakarma, David Wiese, David Wilton, Thomas Wagner, Bert Wouters, Jan Wuite, and The Imbie Team, Mass balance of the Greenland Ice Sheet from 1992 to 2018. Nature, 2019/12/10 2019. https://doi.org/10.1038/s41586-019-1855-2

 

Scanning for Stranded Whales

In recent years, there have been many reports of stranded whales all around the world.  No one really knows why whales founder, and we don’t really know if there are more whales foundering, or if this is a statistical illusion.

The problem is that there is a lot of coastline and shallows, so its hard to know about every stranded whale.  It is also possible that the apparent uptick in strandings may represent an increase in events near populated areas, or improved observation and communications, or some other artifact.

So, just how many whales get in trouble, and where?

This fall, researchers report on an effort to detect whale strandings using satellite data [2].  If this works well, we might be able to assemble some comprehensive data of how many and where whales are beaching.

The key, of course, is high resolution satellite imagery, which is now commonly available with half meter resolution.  This is sufficient to spot whales from space, at least in some cases.

The study compared aerial survey with satellite imagery of a mass stranding of hundreds of whales in Patagonia.  In the images, the whales are easily detected by human eyes, but apparently do not have a simple characteristic spectral signature.  Piles of rotting whales do not all look the same, and do not necessarily look much different from a beach with no whales, at least to an algorithm.

The animals turn a pinkish orange when they decompose (Scale bar: 20m) (Image credit: Satellite image ©2019 Maxar Technologies) (From [1])
In this study, they had only two images to work with, so it’s small wonder that they couldn’t get a good algorithm.  There isn’t, and probably never will be, a huge collection of images to train from.  So, garden variety machine learning techniques will not “just work”, without some serious effort.

Glancing at example images, I’m pretty sure that algorithms should be able to detect and count dead whales.  So, as more data is collected, there will be algorithms.  And that will make it possible to survey large areas and maybe get some solid data.

I was wondering if multispectral data (e.g., IR) might improve the performance of the algorithms, if it were available at sub-meter resolutions.  I don’t really know if partly submerged carcasses would have any distinctive signature, probably not.  So, never mind.

Mainly, we need more data, not just a few lucky images.


  1. Jonathan Amos, Satellites to monitor whale strandings from space, in BBC News – Science & Environment. 2019. https://www.bbc.com/news/science-environment-50040890
  2. Peter T. Fretwell, Jennifer A. Jackson, Mauricio J. Ulloa Encina, Vreni Häussermann, Maria J. Perez Alvarez, Carlos Olavarría, and Carolina S. Gutstein, Using remote sensing to detect whale strandings in remote areas: The case of sei whales mass mortality in Chilean Patagonia. PLOS ONE, 14 (10):e0222498, 2019. https://doi.org/10.1371/journal.pone.0222498

 

Interesting Research on “Deep Carbon”

With all the talk about Carbon emissions and Carbon neutrality and even Carbon sequestration, there is a big question that needs answering:  just how much Carbon is there on Earth, where is it, and how is it moving around.

The Deep Carbon Observatory has been studying this for the last decade and this fall they have published a set of papers in a special issue of Elements  [2].  (What is a cool name and topic for a journal!)

Carbon is one of the most important elements on Earth. It is the basis of life, it is stored and mobilized throughout the Earth from core to crust and it is the basis of the energy sources that are vital to human civilization. This issue will focus on the origins of carbon on Earth, the roles played by large-scale catastrophic carbon perturbations in mass extinctions, the movement and distribution of carbon in large igneous provinces, and the role carbon plays in icehouse–greenhouse climate transitions in deep time. Present-day carbon fluxes on Earth are changing rapidly, and it is of utmost importance that scientists understand Earth’s carbon cycle to secure a sustainable future.   ([4], p. 301)

There is good news and bad news.

The good news is that there is a lot of Carbon on Earth, but most of it is locked up underground.  Less than 1% is at the surface where we humans interact with it, the “terrestrial biosphere”.  Far more is present in rocks, with perhaps 90% of it in the molten core, and most of the rest in the crust including ocean sediments.

So, with this full accounting, we can see that all of our monkeying around with the planet is actually fiddling with the merest sliver of all the Carbon.

The bad news is that the distribution of this tiny fraction has massive effects on climate and the biosphere and on us.

So, we don’t have to touch all that underground Carbon to mess up the climate.  (Just because the ocean has a lot more water, doesn’t mean you can’t drown in a bathtub.)

What is the Science?

The DCO has been working to carefully estimate where all the Carbon is, how it got there, how it has changed over the history of the Earth, and what the effects of the changes are.  A lot of this research is described in the book “Deep Carbon” [3] (available as Open Access here)  (Note:  No, I have not read more than the abstracts.)

The book goes into details about the challenges of figuring all this out. We know quite a bit about geochemistry, what rocks contain Carbon.  But estimating the total mass of all the rocks is an extrapolation from our limited samples on the surface, mining, and digging.

It is even more difficult to try to trace the history of the Earth at these scales, because the Earth and the rocks move and change.  Sometimes the change is slow, sometimes it is fast, and in most cases we have only faint traces from which to infer what geological events have happened.

Much of the history of the Earth’s Carbon occurs in the core and mantle, which are hostile and alien environments to us, and difficult to access.  The physics of these regions is extreme (by the standards of the surface where we dwell) and not as well understood.   And we have only recently discovered that there is life down there, implying that there are poorly understood biological processes at work as well ([3], p. 2)

Building on earlier work, the special Journal issue (Open Access [3]) reports on hypotheses about the perturbations over time of Carbon distribution and flows, e.g., volcanoes, impacts, and rampaging primates.  As in earlier work, this is challenging and there are plenty of uncertainties.

We are most familiar with what they refer to as “terrestrial biosphere”, which has Carbon flows that occur over tens or thousands of years.  The DCO studied the longer term geologic carbon cycle, which involves volcanoes, weathering, ocean sediments, and other transfers.  Changes in the long term system will produce large changes in the short term surface systems.  Hence, the research.

“The long-term, or geologic, carbon cycle encompasses the emission of CO2 from volcanic sources (e.g., spreading ridges and volcanoes at subduc- tion zones); carbon drawdown via silicate weathering and the formation of carbonates, or carbon drawdown via the photosynthesis of carbon by phytoplankton and plants; its burial as either organic carbon or inorganic carbonate; its subduction into the mantle; its eventual return to the atmosphere via volcanic and metamorphic outgassing sources. ” ([4], P. 302)

Figure 1. Carbon reservoirs and cycles in the Earth. The figure shows short- and long-term cycles; “surface” and “deep” carbon reservoirs and fluxes, and the relative sizes and residence times (y axis) of respective carbon. Numbers in brackets refer to the total mass of carbon in a given reservoir, in Pg C (1Pg C = 1015 g carbon). All reservoirs are pre-industrial. Abbreviations: Corg = organic carbon; DIC = dissolved inorganic carbon; MOR = mid ocean ridge; seds = sedimentary rocks. Adapted from Lee et al. (2019 and references therein). (From [4])
The main findings indicate that there have been episodes of sudden, rapid changes in Carbon, often due to massive volcanism.  These can produce long term changes in the surface environment (global warming and cooling), and are often correlated with mass extinctions.

The study found that recent anthropogenic Carbon emissions seem to be of the same speed and magnitude of historic episodes which have led to major long term changes including mass extinctions.  This suggests that all the little apes with their billions of “little volcanoes” spewing are equivalent to a massive geological catastrophe.

Figure 2. Histograms of carbon influx (positive values) and outflux (negative values) to the atmosphere and the oceans. Units are in Pg C/y. (A) Carbon fluxes based on steady state models. Abbreviations: MOR = mid ocean ridge; org carbon = organic carbon. (B) Carbon fluxes as a result of large-scale perturbations to the carbon cycle. Total outgassing refers to events listed in Figure 2A; anthropogenic is human contributions; Chicxulub (Mexico) refers to the end-Cretaceous asteroid impact and resultant mass extinction; average LIP refers to the input from large igneous provinces. Data from Kawaragi et al. (2009), Lee et al. (2019) and Black and Gibson (2019 this issue). (From [4])
Phew!  There is so much more here that I haven’t had time to look at in detail.

Bottom line:  the Carbon cycles that we typically worry about are only a tiny fraction of the whole picture.  Get over yourselves, you little monkeys!

This is good news, in that it means that, however out of whack we drive the biosphere, the overall Earth system can potentially come back into balance.  The bad news is that that would be on geologic time scales, if it even happens.  And other events (an extraterrestrial collision, major volcanism) could occur that would drive the surface climate even warmer.


* Note:  This research is available to all via open access.


  1. Jonathan Amos, Scientists estimate Earth’s total carbon store, in BBC News – Science & Environment. 2019. https://www.bbc.com/news/science-environment-49899039
  2. Marie Edmonds, Adrian P. Jones, and Celina A. Suarez, Catastrophic Perturbations to Earth’s Carbon Cycle (Special issue). Elements, 15 (5) October 2019. http://elementsmagazine.org/past-issues/catastrophic-perturbations-deep-carbon-cycle/
  3. Beth N. Orcutt, Isabelle Daniel, and Rajdeep Dasgupta, eds. Deep Carbon: Past to Present. Cambridge University Press: Cambridge, 2019.  (Open access: https://www.cambridge.org/core/books/deep-carbon/2DD590DAC33871A821E7C9D2826C40D3)
  4. Celina A. Suarez, Marie Edmonds, and Adrian P. Jones, Earth Catastrophes and Their Impact on the Carbon Cycle. Elements, 15 (5):301-308, October 2019. http://elementsmagazine.org/2019/10/02/earth-catastrophes-impact-carbon-cycle/

 

New Baby Iceberg, D28

And another big berg calves in Antarctica!

Ice berg D28 has split from the Amery Ice Shelf [1].  At 1600 sq km, it’s only a third the size of the mighty A68.  But still, it’s a big one, so watch out!

The EU’s Sentinel-1 satellite system captured these before and after images (Image Credit COPERNICUS DATA/SENTINEL-1/@StefLhermitt) (From [1])
(Oooh!  Such a big girl! Who’s a good baby iceberg?  You’re a good baby iceberg.  Isn’t she cute?? )

As far as I can tell, this ice sheet is ‘in balance’, i.e., shedding bergs at a rate to balanced with the inflowing glaciers.  So this part of the ice isn’t going away, at least not at the ice sheet.  (I dunno if the glaciers might be thinning or growing inland.)


  1. Jonathan Amos, 315 billion-tonne iceberg breaks off Antarctica, in BBC News – Science & Environment. 2019. https://www.bbc.com/news/science-environment-49885450

 

Iceberg A68 on the move

We’ve all been tracking A68 (nee Larsen C), the Manhattan sized iceberg that was born in 2017 and is slowly heading North into the Atlantic ocean.  She’s a big girl, and she moves at a stately pace.

She’s two years old now, and finally on the move.  Cryophile Adrian Luckman assembled a nice sequence from satellite imagery.

(Images from [2])

This gif shows A68 has been caught in the Weddell Gyre, a giant ocean eddy that has pulled her 250 km north.  Cruising at a sustained 1/3 km per hour, trillion tonne A68 or her children will likely reach the South Atlantic eventually, there to menace shipping as she melts.

You go, girl!!


  1. Jonathan Amos, A68: World’s biggest iceberg is on the move, in BBC News – Science & Environment. 2019. https://www.bbc.com/news/science-environment-48920168
  2. Adrian Luckman, Happy second birthday, Iceberg A68, in Ade’s glacier gallery. 2019. https://adrianluckman.wordpress.com/2019/07/11/happy-second-birthday-iceberg-a68/

 

PS.  Wouldn’t  “The Weddell Gyre” be a good name for a band?

Under the Ice In Greenland

Greenland’s ice is melting rapidly. That much is clear.  And the implications could be dramatic, as much as 7 meters higher sea level, and drastic changes in the climate of Europe and North America if the major ocean currents change.

But much of the action is happening under the ice, melting from below.   And there are lakes and rivers of liquid water under the ice, which seem to be growing.  This melts the ice from below, creating more water.  This water also lubricates and lets the ice sheets and glaciers slide along faster, down to the sea.

There are computational models of these processes, but there is little solid data on conditions under the ice, so it’s hard to confirm the details.  And the details matter because small differences could make huge knock on effects in the rate of change in the ice.

So, getting under the ice is a high priority for understanding Greenland.  It isn’t easy to get down under kilometers of ice, and it isn’t easy to get data back out.

This year teams from the UK are testing out sensors to be dropped down under the ice, to report on conditions and movements of the water [1].  The concept has been under development for a number of years [2], and it’s finally time to try them out for real.

The instruments will measure pressure, temperature, and conductivity of the water, and will report back with low frequency radio links that should work under kilometers of ice. The “cryoegg” has to be tough enough to be crushed by a glacier, and keep working as long as possible to report where it is pushed to.

“One of the joys of environmental science engineering is that it can be quite ‘Heath-Robinson’ – you won’t immediately find everything you need ready-made in a Campbell Scientific (instrument) catalogue.”  (Dr Mike Prior-Jones, quoted in [1])

This summer will see two tests to see how the design works, in preparation for wider surveys to see what we can find out about the water down there.


  1. Jonathan Amos, ‘Cryoegg’ to explore under Greenland Ice Sheet, in BBC News – Science & Environment. 2019. https://www.bbc.com/news/science-environment-48638958
  2. E. A. Bagshaw, B. Lishman, J. L. Wadham, J. A. Bowden, S. G. Burrow, L. R. Clare, and D. Chandler, Novel wireless sensors for in situ measurement of sub-ice hydrologic systems. Annals of Glaciology, 55 (65):41-50, 2014. https://www.cambridge.org/core/article/novel-wireless-sensors-for-in-situ-measurement-of-subice-hydrologic-systems/3DB2AA304A87519CBF9AB72579E3FDB3

 

Robot Wednesday