Few places have seen climate change more clearly than Greenland. Greenland is a frozen island in the Arctic, about half the size of the United States, with a 3-km thick polar ice cap at its center. The rate at which Greenland’s ice has melted has accelerated over the past few decades, and sea levels have risen accordingly. Recent estimates suggest that Greenland has lost about 270 billion tons of ice per year over the past few decades. This is equivalent to the weight of 26,000 Eiffel Towers, and contributes about 30-40% of global sea level rise. About half of the ice loss comes from ice breakup at the ice sheet’s edge, while the other half comes from surface melt. Understanding why Greenland’s surface melt has accelerated recently and the processes that control it is essential to improving estimates of what will happen to our oceans and the relative impacts on our societies.
This melting has occurred alongside rising global CO2 emissions, and stands in stark contrast to the goals set out in the Paris Agreement signed nearly a decade ago. For this reason, understanding where and how fast Greenland’s ice is melting is one of the keys to understanding the impacts of climate change on our planet, and is the reason for the recent Greenland expedition.
Joining me on this trip are Paolo Colosio, a young but highly skilled researcher at the University of Brescia and expert in polar remote sensing, and Elizabeth Colbert, a journalist who won the Pulitzer Prize in 2014 for her book The Sixth Extinction. We will be staying in Kangerlussuaq, a town on the west coast with a population of about 500, which is the arrival point for international flights to Greenland. The Kangerlussuaq International Science Station (KISS) is headquartered here and will be there to greet us on arrival. The temperature is pleasant, but in my experience it can drop quite quickly as you get closer to the poles.
Previous expeditions have flown onto the ice by helicopter. But as tourism to Greenland has grown, costs have increased and helicopter availability has decreased, making it harder to hire this mode of transportation in recent years. This year, the ice will be reached via a bumpy road built in the 1980s by a car company to test cars on the ice.
I have been to Greenland more than a dozen times now, and I never tire of the sights and emotions of the first step. The sound of ice cracking under our heavy boots, the ice stretching as far as the eye can see, the landscape that is at once lunar and familiar, constantly provoking new emotions and raising scientific questions. It is like coming face to face with an endangered animal, huge and majestic, yet vulnerable to the attacks of small but powerful carbon dioxide molecules that humans release into the atmosphere. It is a privilege and a curse to be here.
New, more powerful satellites, combined with increasingly sophisticated climate models and artificial intelligence, have enabled us to make great strides in understanding the causes of recent melting in Greenland. Despite these advances, it is still essential to explore new technologies to add more pieces to the complex climate puzzle, to promote solutions, and to test ideas. Conducting such research is not a purely scientific exercise. It is essential both in the distant future (hundreds of years) and in the more immediate future (10–20 years), given the catastrophic physical and economic impacts that will be exposed to populations and infrastructure as the planet transitions to a new state. We no longer have to wait for the future to know what will happen in some parts of the planet. The most recent extreme weather events, floods, and wildfires have already shown that the fate of coastal residents around the world depends on what happens in Greenland. The Greenland Ice Sheet is a time machine that allows us to glimpse the past through ice, and it provides insight into what could happen to our planet and the cities we live in.
Drones are one of the tools that can help fill in some of the most important scientific gaps. They allow us to see details inside the ice that satellites can’t see, and they offer the opportunity to discover or improve new processes that can be used in climate models. The drones used in Greenland on this expedition collect images similar to those from very high-resolution cameras, as well as other images that are invisible to our eyes but hold secrets about what’s happening in the ice.
At first glance, it seems reasonable to assume that the melting of Greenland is due to rising global temperatures. In fact, that is true, but there is more going on. One factor that greatly controls the melting of Greenland ice is the amount of solar energy that the ice absorbs. This parameter is called “albedo”, which comes from the Latin word. AlbusOr white. We all know the reflectivity effect and the difference it makes in keeping cool when wearing a white t-shirt instead of a black one on a sunny day. The same applies to Greenland, which gets darker (low reflectivity) or lighter (high reflectivity) depending on the melt-and-freeze cycle and the amount of precipitation. Heavy snowfall is like wearing a white shirt, because fresh snow reflects solar radiation and “cools” the frozen island. As the melt-and-refreeze cycle increases (as it has over the past few decades), the reflectivity also changes. The snow absorbs more solar radiation. This phenomenon is invisible to us, but if we could see it, Infrared In the area, you will see the snow melting more and more and getting darker. The melting and refreezing cycle further accelerates the melting, increasing the absorption of solar radiation, and a kind of “melting cannibalism” occurs where the snow melts itself away.
The Greenland Ice Sheet is a time machine that allows us to glimpse the past through ice, and provides insight into what could happen to our planet and our cities.
We are freezing because of the strong winds coming down from the icebergs behind us. The wind does not make the task any easier, and it requires patience and persistence to operate the equipment. It is a task that can be done without much difficulty in the office, but when you are on the ice, it is an Olympic feat. These same winds are also involved in another phenomenon that reduces the reflectivity of some areas, including where we are exploring. This time, the ice is darker and more visible to us as it accumulates on the frozen surface, such as ash, dust, and sand, which helps the ice melt. The very fine material is eroded by the surrounding rock and then deposited on the ice or caught in falling raindrops or snowflakes. The solar radiation heats the fine particles, forming small puddles around them. These puddles grow in size and depth, and merge to form microscopic lakes ranging from a few centimeters to several meters in length, where the dark material, made up of algae, bacteria, meteorite dust, and other resilient animals, continues to melt the ice.
We expect it to take longer to collect the data due to “normal” unexpected events: drone batteries that were damaged by the carrier and depleted faster than expected, strong winds that limited the drone’s autonomy, difficulty crossing glaciers and canals that were visibly swollen due to melting, fingers that couldn’t fasten small screws because of the cold. But eventually, we’ll get there. It’ll take months to analyze the data. The good news, though, is that preliminary analysis shows that data collected from drones can potentially be combined with artificial intelligence techniques to improve climate models and satellite data extraction. The bad news is that our data confirms that glaciers have thinned by several meters, in contrast to previous years when the change was much smaller.
What makes things worse is the recent changes in the atmospheric circulation in the Arctic. The recent decrease in albedo has been accompanied by an increase in the amount of solar energy reaching the ice. Climate change-related changes in the Arctic atmosphere are increasing the number of cloudless days in many areas where melting is already accelerating, providing more “gas” for melting. The decrease in albedo and the increase in solar radiation reaching the ice are complicit in the climate crime against Greenland. If melting is the speed of the train, then albedo is the slope of the train track, and solar radiation is the gas we provide to the train. Increasing the downhill slope and adding more gas will make the train go faster and eventually unstoppable.
Despite its geographical isolation and remoteness from many densely populated areas, Greenland and its melting ice cover impacts our lives through the combined effects of sea level rise and extreme weather, flooding, and storms. As we look for solutions to reduce emissions and capture greenhouse gases, we must continue to work on understanding how to reduce the uncertainty associated with sea level rise projections, to ensure that the predicted future does not arrive earlier than anticipated, and that many cities and regions are ill-prepared to cope with the consequences. As the Greenland ice sheet melts at an alarming rate, it becomes a mirror to society, affecting us all.
Marco Tedesco is a research professor at the Lamont-Doherty Earth Observatory, part of Columbia’s Climate School.
