Monthly Archives: March 2014

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In 2012 I put together a storify using twitter and weblinks about the  Greenland Surface Melt. In that story a bunch of climate scientists and I talked about whether the extreme melt seen in  2012 was a signature of global warming.

Greenland melt on the BBC
The original BBC Greenland Melting story

An Open Access paper by Sirpa Häkkinen and others Greenland ice sheet melt from MODIS and associated atmospheric variability, published on 10 March 2014, explains how it happened.

Häkkinen et al., 2014 Greenland ice sheet melt from MODIS and associated atmospheric variability
Häkkinen et al., 2014 Greenland ice sheet melt from MODIS and associated atmospheric variability

It is a clear and well written paper that shows using MODIS (Moderate Resolution Imaging Spectroradiometer) data from satellites that you need two things for a serious surface melt event: atmospheric blocking (which allows warm air from the south to go over Greenland) + warm surface temperatures.

The event in 2012 had both of those conditions whereas 2013 did not. The difference is striking in their Figure 1.

Häkkinen et al., 2014 Fig 1
Figure 1 From Häkkinen et al., 2014. Extent of melt on the Greenland ice sheet for (a) 1 January to 31 December 2012 (days 1–366) and (b) 1 January to 30 August 2013 (days 1–243) as determined from MODIS-derived melt maps. A maximum of ~95% of the ice sheet surface (shaded red) experienced some melt in 2012 and only ~49% of the ice sheet surface experienced some melt in 2013. White represents no melting (according to MODIS), and green represent non-ice covered land areas. The location of Summit, mentioned in the text, is shown. Elevation contours are shown at 1500, 2000, 2500, and 3000 m.

Their data set allows them to go back to 2000 and construct annual time series.

And just like Dr Ruth Mottram said in my original storify,

Ruth Mottram Tweet
Tweet used in original storify.

They find all of the features Ruth pointed out (shown in their Figure 4).

They say,

"that June-July 2007 had the most blocking days but did not have the largest melt, although 2007 has been identified as a large melt year in a seasonal sense"

The reason it did not have as much surface melt as 2012 is because the air temperatures brought over the ice sheet by the atmospheric blocking "barely reached 1.5 SDs [above the summer average temperature]". (SDs means standard deviations - basically a measure of how variable the temperature is about the mean.)

In 2012 the atmospheric blocking brought in "a  long-lasting anomaly of 2–2.5 SDs [above the summer average temperature]". This is a bit bland but 2.5 SD's in this data set corresponds to temperatures ~6°C or greater above the summer average on the surface of Greenland. That is why the melt in 2012 was so large.

Häkkinen et al. (2014) make no comment in the paper about the future, or the impact of anthropogenic climate change on such events over Greenland. Looking at various assessments of the scientific literature (e.g the Arctic Report Card) we may draw our own conclusions about whether to expect more of these melting events.

It's very common to hear people harking back to the time when everything was apparently "better". Before the planet was "ruined", before anthropogenic climate change kicked in, and when everybody treated each other with respect.

Of course I don't hold that view.

Polar exploration had a golden age of sorts which is usually called the Heroic Age. It covers the time period when explorers like Mawson, Shackleton, Speirs Bruce and Scott headed South.

I am interested  in the time period before that too.

The British Library have put over a million images on Flickr. With that sort of resource surely there is something polar before the Heroic age?

Searching on the term "Antarctic" throws up a vast number of results -and a couple immediately caught my eye. They were pictures drawn by one of my new favourite artists: the Scot William Gordon Burn Murdoch.

Ever since I started researching and writing about the polar regions I have always been struck by how people seem to imagine them as some sort of "untouched wilderness". This image naturally caught my eye.

Sealing by William Gordon Burn Murdoch
Sealing by William Gordon Burn Murdoch. Source British Library Flickr Stream.

...continue reading

I am working on a polar oceanographic problem at the moment, but the beauty of physics is the principles are universal. That means you can end up reading widely. I came across a very interesting paper (to me):

Gaining insight into Clipperton's lagoon hydrology using tritium
2009 paper in Estuarine, Coastal and Shelf Science

Through the joys of open access a PDF of the paper is available on the Ifremer Archimer institutional repository.

Whilst reading the paper I quickly skimmed over the PDF to see if I was on the right track for what I was interested in. It looked good so I went back to the beginning and starting reading in more detail.

Introduction paragraph 1:

"Clipperton island got the reputation of being one of the most obscure, isolated and unpleasant places on earth"

I thought "eh?" I like a bit of unpleasantness but...

So I read on...  The paragraph gives a quick history of the occupation of Clipperton Island. It was first occupied as part of the phosphate mining industry. But it doesn't have a happy history.

"In this tiny tropical hell, many became desperate to leave, convinced that the island was driving them mad. During World War I, the islanders were cut off from the mainland and died little by little from scurvy and malnutrition. The survivors, a handful of women and children, became ruled by a madman (the light keeper) who proclaimed himself “King of Clipperton”, raping whomever he wanted and murdering any who resisted. Eventually, the women killed him, putting his reign of terror to an end. By July 1917, three women and eight children were the only ones alive and were picked up by the USS “Yorktown”. Its last permanent occupation was in 1944/45 when President Roosevelt ordered the US Navy to seize the atoll. Soon after World War II ended and the atoll was abandoned"

Philippe et al 2009.

Scurvy, malnutrition, rape and murder. I don't come across that sort of thing very often in the area of oceanography I research.

Clipperton Island is about 580 nautical miles off the coast of Mexico.

There is a very good Wikipedia page on Clipperton Island. This is quite surprising given that the atoll is only 6 km2 with a maximum elevation of 29m. It seems to be pretty regularly visited by members of the amateur radio community, and there was a private expedition there in 2013.

If you are interested in the Law of the Sea it seems that in December 2010 the French claimed an exclusive economic zone around the island under the provisions of the United Nations Commission on the Limits of the Continental Shelf (CLCS).

That would mean this 6 km2 atoll has given the French a territorial claim of 1.52 × 109 km2 of sea bed in the pacific and the ownership of the resources there.

Not bad for a place that can barely sustain human habitation.

And the stuff in the paper about tritium was pretty good as well.

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Last week the Royal Society (UK), and the National Academy of Sciences (NAS) released a good PDF booklet called Climate Change: Evidence & Causes.

In the words of the US NAS

"Climate Change makes clear what is well-established and where understanding is still developing. It echoes and builds upon the long history of climate-related work from both national academies."

You can read the background at the Royal Society site, and Carbon Brief provides a synopsis so good I can't add much.

But I will talk about the cover. Here is a screen grab.

The Cover of the Royal Society Climate Change report
The Cover of the Royal Society Climate Change report

I think it's beautiful. I love the way the golden light reflects on the young sea ice. In fact I think it is so beautiful that we used it on the cover of a book I partially wrote and edited for my employer in 2011.

The Cover of the Open University Frozen Planet Coursebook
The Cover of the Open University Frozen Planet Coursebook

The original is an iStock image called "Polar bear on ice close to golden glittering water". Now that is not what I would call it - but then I wasn't fortunate enough to be in a helicopter at that time of the year, and so I don't get to choose.

The Royal Society / NAS had cropped the bear from the image so they used the segment in the yellow rectangle below...

S175 Cover with Crop
The cover of the S175 Book with the crop

They actually rotated and stretched it slightly to completely miss the bear - although there are still clearly bear footprints in the version they use.

I am sure they did that because they did not want to get into the whole "poor polar bear looking over the melting ice" conversation. All the way back in 2012 Carbon Brief included "sad polar bear on melting ice" as one of their Nine climate change pictures I really don't need to see again.

So why did I use it? To me the polar bear is in its natural habitat. The bear is wandering over decaying sea ice and refrozen melt water. Our book is filled with the science of how and why the ice grows and melts, and what adaptations and strategies the animals use to survive, plus lots of other science. The polar bear's Latin name is ursus maritimus - which in English is "sea bear": open water and ice are part of their habitat.

That nuance is not possible in a short but excellent PDF report on climate change, so

I imagine they chose the beautiful light.

In hindsight I think I would have used another image. But only because if you go to the trouble of writing a book, then you would want to keep it special.

The problem I had at the time was that I was not very good at choosing any of my own images.

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The title of the post points to the book Setting Free the Bears by John Irving. It's a book I like and it is about two young people releasing the animals from Vienna zoo after the Second World War.