The Greenland story

It was all over the news, all over the world: 97% of the surface of the Greenland Ice Sheet melting! Quite a lot of sources, including 350.org,  de Volkskrant and het NOS journal got carried away, and announced, either on twitter or on national TV, that 97% of all Greenland ice was gone. They should have spent a second to ponder this: for instance, the offices of de Volkskrant would be flooded if that had indeed been the case. But 97% of the surface experiencing melt is spectacular enough in itself. Generally, no more than 50% undergoes melting in summer. 97% is really rare.

Some twitter sources also mentioned this event had been predicted. In an article, that attracted quite some attention, Jason Box of Ohio State University, and co-workers, stated they expected melt over 100% of the surface to occur in the near future. So what did they base that on, and were they really that precise?

The map showing decreased reflectivity over almost the whole of the ice cap, which gets the bulk of the attention.

Box et al. studied the reflectivity of the Greenland ice. Reflectivity, or albedo, is one of these things that stabilises ice sheets; it reflects sunlight back so effectively that the radiation can hardly make a start at melting any ice before it finds itself reflected back into space. But if high temperatures manage to get the melting process going, this lowers the reflectivity, and then your ice and snow are in peril. This self-reinforcing process, also known as positive feedback, might well herald your ice cap’s decline. What’s even worse is dirt blown on top of the snow; this may start melt at lower temperatures.

So what did Box and his fellow scholars do? They basically measured reflectivity and melt from a satellite, calibrated these results with observations from weather stations on the surface, and ran a climate model in order to get an idea of the sensitivity of the reflectivity to temperature. And what is so new about this research? Satellites have been measuring the albedo of Greenland for many years, and ground-truthing with weather stations has been done since early days too. But the results of Box et al. go all the way to the year 2011, bringing this research up to date. And their combination of observations and modelling could potentially give new insights in how the process works.

Observations of reflectivity

So what did Box and colleagues find? The reflectivity of the Greenland Ice Sheet is at a low point; 8% lower in 2011 than it was in 2000. And this is not an incident; they have observed a significant trend, though admittedly a short-term one. They further found a 26% increase in melt between 2000 and 2011. And to give you an idea of how much that is: if that rate would remain constant at 2011 level, the ice cap would be lost in roughly 6000 years. And the sensitivity of the reflectivity to temperature? That’s where it gets confusing. Over large areas of the ice sheet, reflectivity only goes up with higher temperatures. This can be explained by warm air bringing in more snowfall. But strangely enough, snowfall doesn’t always correlate with higher reflectivity in their data. And when you look at the sensitivity of the reflectivity to temperature, or in other words; by how much the albedo goes up or down with every degree temperature change, it becomes clear that their data is only statistically robust in the regions that are melting already.

The authors warn that they think summer melting will occur over the entire ice sheet in another decade, if the coming years will be like 2010 and 2011. But that is a big “if”. Box emphasizes only the decreased reflectivity in his own blog post, without being too specific about the lack of straightforward relation with actual melting. The big take home message of this paper might be that the processes governing ice melt are not yet sufficiently understood. And we want to understand it, if only to get an idea what we should do with our coastal defences. The amount of melt in 2011 measured already translates to more than a millimetre of globally averaged sea level rise. And that does not sound like much in itself, but it does when you realise it was only 1.7 mm/year on average for the 20^th Century in total; that includes for instance Antarctica, mountain glaciers, and thermal expansion.

So did they predict the ~100% melt?

Well. In a way they did. But what they really predicted was a shift to net melt over the area that nowadays experiences net snow accumulation, averaged over the whole summer. They did not mention short periods of 100% surface melt. However, you can’t get to net summer melt without, well, melting large areas of the surface once in a while. So people who say “they predicted this!” are exaggerating. But Box and colleagues are right in saying that this event greatly supports their conclusions. Given the uncertainties in their data, this was more a lucky guess than rock-hard data, yet I hope it will attract attention to the danger of Greenland melt. It’s not as if we who are alive today will ever see an ice-free Greenland, but we may well see a Greenland Ice Cap that raises average sea level by 2mm per year or more, and that is something we need to prepare for. Those who love Amsterdam, London, New York or one of these other iconic cities near sea level might wish Box luck in keeping up the good work…

Standing up for Science

“We try to get it right, and we are generally nice people!” If people feel the need to confirm this something is probably wrong. So who was saying this to whom? It was a science journalist in front of a room full of scientists. They should be the best of friends; science journalists wouldn’t have a job without scientists, and scientists would struggle to get their work noticed by society without the science journalists. But a lot of mistrust hangs over this collaboration.

Where did this attempt to bridge the abyss take place? At a course on science communication “Standing up for Science”, organised by “Sense About Science”. The latter is a charity aimed at helping scientists to get their message across, and helping the community to find the scientific support it needs. They were approached, for example, by an organisation of fire fighters, who were worried about clambering around on roofs just next to phone antennas. Would the radiation pose a threat? If one asks internet one can get all sorts of loudly proclaimed opinions, but who to trust? Sense About Science will show you the way!

The glamorous venue at Belgrave Square, kindly provided by the Society of Chemical Industry

Another of their actions has been to write a flyer on the peer review process. For those unfamiliar with it; it is the selection process scientific manuscripts go through. If you send one to a journal, the editor will ask a few fellow experts in the field to review your manuscript. They can recommend publication as is, revision, or rejection. The editor has the final say. As scientists have something to lose by letting standards slip, this process tends to be very thorough. Sense About Science has explained it a bit better than I just have. They point out the merits, but also the weaknesses of this process. And explain the relative merit of peer-reviewed sources compared to other sources. And they have sent 1/2 million copies out in all directions, making it a part of civil service training and a school resource. One could assume many lay people would not be aware of this phenomenon, and might make the mistake of equating proper scientific literature with, say, any polemic in a blog. They also sent a flyer about statistics and how to make sense of them to it to all MP's and lords in the houses of parliament! And I don't know how many of these flyers have gone linea recta into the waste paper bins, but every single one that is read and taken heed of is a major triumph.

At this occasion they had organised a workshop for early career scientists to give them some advice of getting their message across. In order to do that they had invited three panels of experts: one with researchers who had lots of experience with the media, one with science journalists, and one with people such as media officers.

One of the researchers, Steve Keevil of (among others) King’s College in London, had a fascinating story to tell. He was involved in MRI science; something evidently very societally relevant. His field was shaken up when an EU directive would become effective which would seriously limit the use of MRI. All with the best intentions, but in effect severely limiting the diagnostic methods available to the medical profession. He had alerted some powers that be, but these had just said he had to live with it. EU directives are irreversible!

The panel of researchers. With Steve Keevil talking

He had then contacted Sense About Science. They had advised him to send out a press release and hold a press conference. He thought they had gone mad! But he did it. And it caught the attention of the public. And through that, it caught the attention of politicians. Before he knew it he was on a panel that advised parliament. That EU directive has been postponed more than once. And is likely not to be passed at all. Victory!

The journalists, after reassuring us they’re not trying to stitch us up, also had interesting stories. One lady working for science programmes on the radio (Michelle Martin) said she often phones scientists to see if they are willing and able to collaborate on a programme. And that phone conversation is the dress rehearsal. So scientists; don’t save your brilliance for the actual interview; if you do that it may not come!

The last panel included a lady from SAS itself. She encouraged us to become a member of their network “Voice of Young Science” (VoYS); the people they call on if they get a request from the public. They always have use for more people! And it is a great chance to now and then really make a difference. I was glad to hear that you don’t actually have to be below any specific age to join...

A selection of publications SAS has produced

With all these panels the room had lots of discussions, and between these sessions there were group discussions of only the scientists. It was great to hear all these things, get all sorts of new ideas (I’ll start tweeting! And join VoYS! ) and make contacts with all these other people out there who are interested in science communication.

My last question was if someone had a tip on how to deal with aggressive comments. One quite regularly bumps into climate sceptics who think all scientists are part of some nasty conspiracy, and they are not particularly keen on listening to a balanced scientific argument. It’s all part of the conspiracy, right? A Danish girl stepped in there, and said she had witnessed an astronomer being interrupted by someone saying “but the moon landing, that was all fake, wasn’t it?” The astronomer then didn’t open a register of scientific publications based on the moon landing; he just said “if it was fake, don’t you think the Soviets would have found out, and loudly exposed this scam?” I should keep that answer in mind...