Polar bears and sinking towns: Challenges of monitoring climate change in the Arctic Circle

ITV News' Science Correspondent Martin Stew, Producer Philip Sime and Camera Operator Barnaby Green report from Svalbard in the Arctic Circle

In the lashing rain today, the environment 79 degrees north in Ny-Ålesund is brutal. It’s also fragile.

The nearest town on this island, Longyearbyen, posted its warmest summer on record today.

It's why climate research scientists are investigating how changes to temperatures are impacting the local wildlife. Assessing how behaviours may change, and if species can even survive.

Max Willems is a Dutch scientist working for a German research team in Norway. Her focus is on the Fjord, a narrow body of water, and the fish who call it home.

The surface temperature of the Fjord at this time of year is usually 5C, but this year it's 7C. That may be a short term blip but the long term trend shows the waters are warming.

Inside two controlled tanks, small fish are swimming against a current. “We are giving the fish a fitness test," Max tells me.

The current speeds up and oxygen levels in the water are monitored to see how hard the fish are having to work.

The experiment is then repeated over and over in slowly increasing temperatures to see how the warmth affects their stamina.

"So what I expect, and what my colleagues expect, is that when the water gets warmer, they will have a rougher time maintaining their fitness. It will cost them more energy to do their basic living," Max explains.

The fish may be small but they’re a vital part of the food chain. A so-called ‘keystone species’.

“I fear that the water will heat up too soon, too quick,” Max says. "And too much for them to fulfil their basic needs, and the animals that are dependent on them - like the polar bears and the narwhals."

It all sounds rather depressing but Max believes there is hope. Her experiment suggests the fish can swim at slightly warmer temperatures, but she doesn’t yet know how much heat they can tolerate.

"I think if everyone bands together and we try to limit the increase of water temperature amongst other pollutants and things like that … they can maintain. They are pretty sturdy guys."

Grazing behind a nearby building is a wild reindeer. Vegetation is easy to come by in the summer. In the winter they dig through snow to access greenery. The problem is ice.

Scientists are noticing an increase in winter rain which freezes as a hard layer, impenetrable to hooves. The fear is this could lead to reindeers starving over the long dark winter months.

Even accessing the scientific sites dotted around the outpost is increasingly tricky.

This is also polar bear country - it’s their home and they are the apex predators. Scientists have to carry guns as a last line of defence, but the focus is on avoiding contact if possible.

Flare guns fire a loud warning and rangers on radios coordinate to keep people and bears safe.

No British scientist has ever had to shoot a bear here and they intend to keep it that way. But sightings near Ny-Ålesund seem to be on the up.

There were four sightings in the last fortnight alone including the rare sight of a bear killing a reindeer.

"I have only been here six years," Harbour Master Erland Havestrom tells me.

"That's, of course, a short perspective. But, when you hear the stories, you follow the research going on … there is a change here.

"There are more changes here now during summer instead of wintertime, like the sea ice is gone, more or less. So, they're not here during spring hunting seals on the ice anymore.

"They're here during summer on the islands, eating bird eggs. That's a huge change in behaviour locally here. So, something is changing for sure.”

Tomorrow we’re heading out on foot to a nearby glacier retreating up the valley.

Nutrients washed into the Fjord by meltwater turn huge swathes of the water a pinky red. Another thing which could alter this rapidly changing ecosystem.

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