ARCTIC CAVES
The polar regions are heating twice as fast as other places on Earth and with that comes melting ice. To better understand how this will impact the planet, scientists need to study past climate change and past warm periods. Caves hold some of these secrets. Rolex Award recipient Gina Moseley talks through her plans to abseil into the planet’s most northerly unexplored caves, situated in Greenland, and to seek lessons from the past that could help us in the future
At present, what we know about past climate change in Greenland mostly comes from deep ice cores that are drilled from the ice sheet. But the limits of the Greenland ice core record is 128,000 years. There’s limited scope to go back further in time because, during past warm periods, the ice sheet melted. Caves offer the opposite: they sit there all the time recording.
When we enter caves, we first map and photograph them and then do some temperature measurements. And then for my work we sample them. This is usually speleothem samples – a collective term for stalagmites and stalactites and those sorts of mineral deposits. In Greenland, there aren’t so many stalagmites and stalactites, there are more of what we call flow stone. Whereas a stalagmite or stalactite forms from drips of water, a flow stone forms from thin sheets of flowing water. Because they form layer by layer, they’re similar to tree rings: with each passage of water some calcite is deposited, and that contains within it a chemical record of the climate and the environment of the cave at the time of deposit. Caves actually become more active when the climate warms up because when it gets wetter, the ground thaws – that allows moisture to get into the caves and then the spelothems form. It means that the samples we get from the caves tell us about a period in the past that was warmer and wetter than today. Researching the past in this way gives us a baseline for whether the present changes are unusual or not. And they are also really useful analogues for what we might expect in the future. It could help us to improve predictions.
The wider rationale is that the Arctic is warming twice as fast as the global average, so it’s highly sensitive to climate change. And when we have these changes in the Arctic, it has such an impact around the rest of the world. So not only does the ice sheet melt and sea levels rise, but if you reduce the temperature gradient between the equator and the poles, then that affects pressure systems and leads to things like extreme flooding in Europe, or extreme heat waves in the northwest USA. This is why we need to improve our predictions.
I have led three expeditions to Greenland already and now the Rolex Award is funding this expedition to a big cave in north Greenland that is not yet explored. The caves there look to be much more exposed than what we’re used to: they really are in cliff faces hundreds of metres high. We don’t have a lot to go on other than a few photos, but we’re expecting that we’ll need to abseil in that’s for sure. Normally, caving is not very attractive to funding bodies, but crucially for me, Rolex are interested in high-risk, high-gain ideas, and the value of just trying something out and seeing if it works.