Timelapse as seen by a glaciologist, interview with Luc Moreau

Today is Earth Day! We've been talking about it all week on the site and on Facebook. We've got an interview for you!

We interviewed Luc Moreau to find out more about glaciers. Luc Moreau is an independent glaciologist attached to the EDYTEM (Environnements, Dynamiques et Territoires de la Montagne) laboratory at the CNRS in Chambéry, who has been working for ten years with automatic cameras and timelapses to study glaciers in the Alps, Greenland, Nepal and Patagonia.

– What does a glaciologist do?

Luc Moreau: The job of a glaciologist involves measuring and observing glaciers. I specialize in measuring glaciers and the water that flows beneath them. This water can be harnessed by hydroelectric companies, and I work with some of them. We look at how the glacier and its movement react to climate variations. There are other specialties, such as those of most glaciologists at the Grenoble Glaciology Laboratory, who work mainly on deep core drilling.

– Why are you interested in glacier movements?

Luc Moreau: Generally speaking, studying glaciers means studying a very important natural element in the water cycle, and one that is vital to our planet, not only for its advantages, but also for the dangers it sometimes poses to human populations. It's also interesting because they archive the composition of the atmosphere and the quality of the air trapped in bubbles... but it's more the chemical glaciologists who work on this.

Glacier movement is linked to temperature: in Greenland, glaciers are accelerating as the sea warms up. For example, the summit of Mont Blanc is very cold, at -15°, so it only moves two meters a year through deformation. But at altitudes below 4,000 metres, glaciers start to melt, and the snow contains water (which is brought down to 0° at the end of summer, known as a temperate glacier). The glacier then glides like a ski, descending at speeds of up to 2 metres a day. When it reaches a lake or the sea, as in Greenland, the glacier will float and can accelerate, moving up to two meters per hour. It's the fastest glacier in the world, moving 50 metres a day! I'd already set up automatic cameras to study it, and for the last five years we've been studying the Eqi glacier in the Bay of Quervain.

– How do you use timelapses?

Luc Moreau: We can't always be on site to observe glaciers, and automatic cameras are a great help! We can see how the glacier evolves, how it reacts all year round, in every season, every month, every day. The camera becomes our eyes. For the Eqi glacier, we already have photos taken every 20 years since 1912, and timelapses since 2011, which show the glacier's speed (10 metres a day), but also that its length is decreasing (like all the world's glaciers, with a few exceptions!). And then there are areas where you can't go to measure because they're too crevassed, too dangerous, and here the automatic camera comes in very handy and indispensable!

« The camera becomes our eyes »

– Taking photos in these sometimes difficult climatic conditions must be very demanding.

Luc Moreau: Indeed. First of all, you have to have a fixed framing, so the camera has to be firmly attached to the rock. Snow and frost on the lens can also be a constraint. And so can temperature variations, which affect the camera's batteries. In Greenland, the camera bodies were made by the team at the Femto-St laboratory in Besançon, using Leica cameras. A solar panel powers the camera's batteries. These cameras were developed in 2007, and were not yet commercially available. These are prototypes that work well: in Greenland, some cameras last a year at -20°, taking one photo a day! Of course, there can also be minor technical bugs, but these are prototypes.

– How do you use these photos?

Luc Moreau: When we study a glacier, we measure it and place markers. We use aerial and satellite photos, place markers and carry out a health check on the glacier. When we know the distance between the camera and certain visible landmarks precisely located on the glacier, we can then make calculations. By editing the timelapse images, you can also see the dynamics of glacier movements! And you can even calculate its speed using the pixels in the images. This is great, because you don't necessarily get the impression that glaciers are moving so fast. They evolve, they live, and that can be very fast!

– How do you feel when you return to a glacier and see that it has completely melted?

Luc Moreau: Completely melted, maybe not, but let's say the glacier has completely changed its appearance or morphology. It's true that small glaciers can disappear quite quickly. In the Pyrenees, for example, we know that in 30 or 40 years there will be none left. We realize that glaciers are highly sensitive monsters, to climate variations for example. You don't necessarily get the impression that they are, but when you come back two or three months later, you realize that they have melted, shortened or moved very quickly.

In the Greenland Sea, for example, since I set up a camera in 2011, the Eqi glacier has lost more than three kilometers! I even had to move the camera because the glacier had shortened too much and was no longer in the frame!

It's very spectacular, even more so when you edit the images and see the glacier moving in timelapse! There are many phenomena that can only be seen like this.

– What role do glaciers play in global warming today?

Luc Moreau: Glaciers make climate change visible. We often talk about invisible things: temperatures, energy balance, melting and greenhouse gases. These are tiny, invisible things, but they are permanent and continuous. That's why some people find it hard to believe! The glacier will undergo all this and make the invisible visible.

– Do you think the timelapse helped alert public opinion to the climate emergency?

Luc Moreau: Yes, of course! When you see natural elements that react very quickly to the climate, like glaciers, and you make a film over several years (I tend to make long timelapses), it's very telling. You don't need to explain, you can see immediately, in accelerated form, the invisible evolution of something else! But it's not that simple. Just because you see a glacier shrinking doesn't immediately mean that global warming is taking place! As it happens, summers have been hot for the past 25 years. Glaciers are shrinking as a result of greater loss than gain from snow.

But they haven't always shrunk just because of temperatures! But also because of a lack of snow. This is what happened in the 1940s and 1950s. Then, in the 1970s, glaciers increased in thickness due to heavier snowfalls and cooler summers. That's why we prefer to talk about climate change rather than warming, because it also affects precipitation. It's better to have warm 0° winters with snow than cold, dry winters.

We'd like to thank Luc Moreau for giving us the time to write this article, and we're sorry we couldn't write down our entire exchange! If you liked this article, please feel free to comment on it or visit Luc Moreau's website.