They trick the eye but the crash and thunder of Greenland's vanishing glaciers sound a deathly warning to the world

Earth on the Edge is an ITV News series dedicated to showing you the areas of the globe already facing environmental catastrophe.

In this report, Science Editor Tom Clarke travelled to Greenland to see the visible evidence of glacier melting that is changing the island's way of life and threatening the planet.

Greenland’s glaciers are so huge - they trick the eye.

But you know when you’ve got close to the front of one because you can feel it.

Even on a mild day, a freezing wind hits you.

Air above the glacier is chilled by the ice, so it flows like a river down the valley and over the edge.

A pack of broken blocks shines in a sea of ice whose slow rise is worrying scientists. Credit: Tom Clarke

The ice is flowing as well.

Too slowly to see, but you can hear it.

The wall of ice creaks and thunders.

Until gravity finally wins and giant pieces of ice break off the front and crash into the sea.

This process, called calving, is how icebergs are made.

We’re keeping several hundred metres away from the front.

The boatman keeps the engine running.

The waves created by calving icebergs can flip a boat over.

Greenland has seen a sharp increase in the calving process. Credit: Tom Clarke

Calving is a part of life for an ocean-terminating glacier.

But in Greenland - and most of the rest of the world - calving is getting more frequent.

Glaciers are accelerating, and thinning, as the planet warms.

Many stand tall, but the warming planet is lessening the size of glaciers. Credit: Tom Clarke

This is raising sea levels almost imperceptibly but relentlessly.

Jakobhavn Glacier discharges in a single day the same amount of fresh water as New York City consumes in a year.

Right now the sea level is rising by nearly 4mm a year.

Small differences in sea levels here have enormous consequences elsewhere.

By the end of the century that could be a centimetre each year.

It’s not much - but try telling that to someone flooded out of their home by a storm surge caused by a typhoon or hurricane.

The melting is also changing Greenland.

We head further south to Nuuk, the capital.

In a fjord a few hours’ boat ride away we watch the water turn from deep blue to milky white.

Fine sediment is being scoured out by the glaciers and washed into the sea.

The view from the air shows the impact of recent changes in climate.

West Greenland’s oceans are some of the most productive in the world.

Filled with tiny shrimp-like plankton that feed fish that, in turn, feed seals and whales.

Oceanographer Jane Hatton is leading a team from Bristol University and the Greenland Climate Research Centre to try to understand how melting glaciers might impact the biodiversity of the oceans around Greenland.

Oceanographer Jane Hatton is leading an effort to research the melting effect on marine life. Credit: Tom Clarke
The Bristol University and the Greenland Climate Research Centre team work from a former naval vessel. Credit: Tom Clarke

Using various instruments dropped over the side of an ageing ex-naval vessel, they’re looking at how changing amounts of nutrients and changing temperatures are impacting marine life.

Speak to the fishermen around Greenland and they’ve already noticed a difference.

There are many more whales here, they say.

We see humpbacks and a pod of eight fin whales - the second largest species in the world.

The change in ocean life has attracted some more frequent visitors. Credit: Tom Clarke
The pods of humpback and fin whales are attracted by increasing food supplies. Credit: Tom Clarke

One theory is there is now more to eat in the oceans off Greenland.

But if it is linked to global warming, will the bounty continue if oceans keep warming?

Lars Mathaeussen and Johannes Heilman have been hunting and fishing around Nuuk since childhood.

Greenland's historic fishing industry has changed.

They take us out to nets they have set for salmon.

They haul four silver-blue fish into the boat.

A small catch.

The warming climate has reduced their catch, they say.

The freshwater from the melting ice floats above the salt water.

Local fishermen are seeing a reduced catch while industrial fishing is thriving.

Pushing down the salmon and other fish, deeper than their nets.

Further out to sea, commercial fishermen have no such problem.

In fact, retreating sea ice has made their job easier.

They can spend more days at sea fishing.

And that’s led to another type of problem: overfishing.

An entirely new concept for this huge island of just 56,000 people.

It’s possible that continued warming could push the Greenland ice sheet - with its potential to raise sea levels by 7m globally - into an irreversible melting.

An event that would change our planet in unimaginable ways.

According to this week’s IPCC (Intergovernmental Panel on Climate Change) report if global temperatures don’t rise much more than two degrees, that tipping point is unlikely to occur.

If Greenland's ice sheet continues to disappear the consequences for the planet are irreversible. Credit: Tom Clarke

But based on current trends, we’re heading for three or four degrees of warming.

Making that dreadful possibility an inevitability.

More from our Earth on the Edge series:

In the first part of the series, ITV News travelled to the frontlines of the world's deforestation crisis.