Exploring Antarctica in Cambridge

My research uses ice cores drilled from the Antarctic ice sheet to learn about past climate. In the most extreme case these cores extend all the way to the bottom of the ice sheet, through 3 kilometres of ice and 800,000 years of climate history. They show us how ice ages have come and gone.

Air bubbles within the ice allow us to see how carbon dioxide has varied with those natural climate changes, and then how the amount of carbon dioxide has rocketed outside its normal range in the last century. My most recent research looks at how the West Antarctic Ice Sheet behaved the last time Antarctica was a little warmer than today. This has obvious implications for what could happen to sea level in the future.

To do this work we travelled as a team of 8 scientists and engineers to Skytrain Ice Rise, a remote part of the ice sheet. There we slept in two-person pyramid tents, and ate together in a larger communal tent protecting us from the temperatures of -20 degrees and the strong winds. First we had the arduous task of building the camp and getting the drilling equipment in place.

After that work consisted of a sequence of lowering the drill down the hole, collecting another metre of ice, measuring, marking and bagging it for transport to the UK and repeating the sequence. After 45 days of that routine we reached the bottom of the ice sheet, at a depth at this location of 651 metres. A successful conclusion, and a happy return to warmer climes!

The oceans around Antarctica play a key role in controlling our planet’s climate. They do this by absorbing huge amounts of carbon and heat from the atmosphere, including the additional carbon that humans put there by burning fossil fuels, and the extra heat trapped by the greenhouse effect.

By doing this, the oceans are doing us an enormous climate favour, helping to slow the rate of global warming on land – but we don’t know how this will work into the future. 

My research looks at how the ocean absorbs so much heat and carbon, where it all ends up being moved to and stored, and how likely this is to continue into the future. To do this, I work in teams that sail on the UK’s polar research vessels, spending weeks or months at sea making measurements of ocean properties and circulation, from the sea surface right to the seabed, sometimes miles down. 

Whilst many measurements are made directly from the ship, we also increasingly use robotic vehicles that can be deployed from the vessel or from coastal stations in Antarctica, and piloted remotely from the UK.  Whilst the conditions at sea around Antarctica can be rough and it’s difficult being separated from family and friends for long periods, life at sea is still an extraordinary privilege – we get to see some of the most stunning views and incredible wildlife that the planet has to offer, whilst helping to better our understanding of climate change.

I am based at the Scott Polar Research Institute, where I am – amongst other things - a specialist in the use of satellite (and now also drone) images to study polar landscapes.

A lot of this work is concerned with understanding the relationship between climate change and the behaviour of trees and shrubs in the far north of Eurasia, but I also collaborate with Dr Peter Fretwell at British Antarctic Survey (BAS) to develop new methods to study the distribution and behaviour of animals at high latitudes.

A few years ago, this collaboration led us to the conclusion that we needed to understand, and this may be one of the most bizarre phrases I have ever typed, the optical properties of penguin guano (‘poo’ to most of us).

Why on earth would anyone need to do that? Well, the diet of some species changes, during the breeding season, to one high in krill, a little shrimp-like crustacean which, like shrimps, is pink.

Pink material goes into the penguins at one end, and pink material… comes out at the other end. The pink guano stains are a marker of the presence of the penguins, and if a penguin colony is big enough, we can see it from space. To really tie this relationship down properly we needed to understand just why the guano is pink, and that involved travelling to a place with a lot of penguins and making a lot of optical measurements, of pink guano, white guano, yellow guano (it is actually quite a colourful material!), and… penguin vomit. The vomit is what the penguins collect as food for their chicks, carried in their stomachs, and it contains a lot of krill.

I travelled, with my PhD student, to the BAS research station on Signy Island. This is very small – it can accommodate at most eight people – and it is difficult to reach.  The island is very mountainous, with an icecap in the middle, and there is nowhere that a plane could land so it has to be reached by ship – which isn’t easy since there is often a lot of ice in the sea.

The base is too small to have specialists like cooks and doctors, so everyone has to do everything – cleaner, night watchman, radio operator… It was, and felt, very remote indeed, and it was sobering to realise that the only way to return home was if a big ship could manage to reach the island again, pushing its way through the ice, in a couple of months’ time.

A typical day on Signy Island: After breakfast in the main building, we get dressed in our special clothing. It’s not excruciatingly cold but we have to be careful. We leave a message on the board to say where we’ve gone and when we should be back, and we check the radios. It takes an hour and half to walk through the snow from the base, over a mountain pass, to reach the research hut at Gourlay 2½ miles away.

We have some heavy equipment to carry so it is quite hard work (I lost half a stone of body weight during my field trip). At the hut, we can make ourselves a cup of tea on the Primus stove, then move out to where the penguins are and start measuring their ‘offerings’. We do this for a few hours, with a break for lunch in the hut, and sometimes a break for taking photographs because everything is so spectacularly beautiful.

Then, we pack up and walk back to base, in time for dinner cooked by whoever is on the rota for that evening. We are all hungry, because the work is so physical. After dinner we might play cards, then spend a few hours in our ‘lab’ processing the data we have collected during the day, then maybe do some personal chores like washing clothes. And.. repeat, for about two months.

What did we learn from this expedition? We conclusively identified the reason for the pink coloration in the penguin guano (you can read about that here), and that means that we can now more confidently estimate the population of penguin colonies without needing to visit them. And penguin populations respond to environmental conditions over a wide area of the Antarctic, so we have a better understanding of the  way the changing climate is altering the biology of this huge and remote region.

My research uses clues from the past to predict the future of Antarctica. Thousands of years ago, the Antarctic Ice Sheet was much larger than it is today. As the ice sheet retreated, areas once covered by ice were flooded by rising seas.

Like footprints left in the sand when you walk along a beach, this ice left behind a record of its retreat in the sediments now preserved at the bottom of the ocean. My research uses sonar from icebreaking ships to map out these ancient records left behind on the Antarctic seafloor.

Because it is difficult and dangerous to examine the environment underneath modern-day ice sheets, these accessible marine records provide valuable information about what goes on beneath ice sheets as they retreat. This research ultimately helps us to predict how Antarctica will respond to climate change in the future.  

Antarctica is an otherworldly place; a land of contradictions. It is a continent that, despite being covered in frozen water, receives so little snow that it technically counts as a desert. Its immense sheets of ice are deceptively fragile. It is a beautiful, yet hostile, place.

Standing on the bow of the ship surveying this rapidly changing environment, you are surrounded by shades of pastel blues and whites in the day and fiery sunsets in the evening. Icebergs gurgle as they drift past in the current, the wind rushes past your ears, carrying the cries of squawking penguins from the immense breeding colonies fringing the edge of the ice sheet.

The time we spend there is short and precious so we work in shifts — twelve hours on and twelve hours off — seven days a week — to maximise the data we collect when we are there. Although I usually work the night shift, the sun does not sink below the horizon in the summer months, making it difficult to detect the passage of time.

It is an immense privilege to work in this colossal wilderness where the changes happening in this remote part of the world will ultimately affect us all.