Sudden ice melt in Greenland shocks scientists
In the past two weeks, a sudden and dramatic melt has turned almost the entire surface of Greenland from ice to liquid water. This is totally unprecedented – but is it global warming?
Greenland is the largest island in the world. Almost all of its miniscule population live by fishing and hunting, huddled in a tiny collection of towns and villages at the island’s southwestern tip. The rest of the land is totally inhospitable, covered in a vast sheet of ice up to 4 km thick.
This ice has been formed over millennia, as layers of snow freeze firm in the perpetually sub zero conditions. In the summer months an ever-present sun heats the ice sheet just enough that around half of it melts on its surface. At the beginning of this month, for instance, 40 percent of Greenland’s ice had thawed. That is entirely normal.
But what happened next is not. Over the course of just four days, almost the entire surface of Greenland turned to liquid. By July 12th, an astonishing 97 percent of the ice sheet had thawed. Even at Summit Station, the island’s highest and coldest point, tiny streams of water started to form.
In the thirty years since scientists started observing Greenland’s ice sheet, they have seen nothing that compares to this. Usually calm rivers in the south became blustering torrents. One researcher was so shocked when he saw the data yesterday that he initially refused to believe it.
This news has come hot on the tail of another momentous melt: last week, scientists reported that a large chunk of ice had broken off a glacier at the edge of Greenland. It will now become a free-floating iceberg in the North Atlantic.
Is this global warming? That is the question which everybody is asking – but it is surprisingly difficult to answer.
Earth’s polar ice is constantly in flux. Each year, parts of it melt, only to refreeze days later. Huge chunks of glacier snap off their moorings; but dramatic as it is, nobody notices a thing.
Humans have only just begun to pay attention to the slow, mysterious rumblings of the world’s icy places. With so little experience, it is difficult to tell just how unusual this month’s occurrences are. It could be the omen of a cataclysmic meltdown; but it could simply be a quirk in the Earth’s natural rhythms.
Even climate change specialists are unclear about what this means. So what is the point of ordinary lay folk trying to understand? Zero, say some. This is a matter for the experts; the rest of us should stop speculating and simply get on with our lives.
That is sheer complacency, reply others. What is happening to our planet is a question that ought to concern everybody. True, there are no clear answers; true, we must rely on experts instead of our own opinions. But the better informed we are about climate change, the better our responses will be. And that could be the most important issue of our age.
- Are you scared of global warming? Should you be?
- Can those who are not scientists add anything to debates about climate change?
- Make a poster displaying ‘Five things you need to know about global warming.’
- Research glaciers and draw a diagram showing how they are formed.
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“Climate change is the greatest threat that civilisation as we know it faces today.”
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Q & A
- Will this cause sea levels to suddenly rise?
- Not immediately. Almost all of the water will quickly refreeze; other parts will cling to the ice sheet. Some will trickle off the edge of Greenland and into the ocean; but not so much that the rest of the world would feel the effects.
- Oh. So what’s the worry?
- If this melting became a regular occurrence, it would have a serious impact on sea levels. But this could take thousands of years, since the water would have to trickle down from the land. Perhaps more importantly, unusual melting patterns could be a signal that the global climate is changing fast. Besides causing other melts with more immediate impact in the Arctic, that could mean drought, extreme weather, food shortage and mass extinction.
- Miniscule population
- Amazingly, only 57,000 people call Greenland their home. They have long been ruled by Scandinavian powers, and technically Greenland is still a territory of Denmark. However, they have recently been granted significantly more independence, including their own parliament. Facing some of the harshest living conditions in the world, Greenlanders are plagued by diseases like HIV and social problems such as alcoholism.
- Saw the data
- Very few scientists stay on the surface of Greenland for long – certainly not enough to make accurate observations about conditions across the entire island. Instead, satellites take infrared images of the surface to determine how much of the water has turned to liquid. These results are collected and analysed at universities around the world.
- Ten percent of the Earth’s surface is covered by glaciers – large and long-term blocks of ice formed from frozen precipitation. They contain around 75 percent of the world’s fresh water. If they all melted tomorrow, the world’s sea level would rise by an apocalyptic seventy metres.
- Natural rhythms
- Besides the annual pattern of melting and refreezing, there are also longer-term rhythms that govern the behaviour of polar ice. Scientists analysing Greenland’s ice have concluded that an unusually dramatic melt occurs roughly once every 150 years – which may possibly explain the current phenomenon.