The southern peak of the massif of Kebnekaise is the tallest mountain in Sweden, but it might not hold the title for much longer – after a week of particularly hot weather, the mountain has started to shrink.

In fact, the glacier-topped southern peak might already be lower than the rocky northern peak, after four metres (about 13 feet) of snow and ice melted off the top of the mountain in less than a month, an average of 14 centimetres (5.5 inches) a day.

The height of the mountain constantly varies as the weather changes, but temperatures in Sweden and all across Europe have been especially high this summer.

Many parts of the country have seen records broken for hot weather in July, and on average the temperature was 3-5 degrees Celsius (5-9 degrees Fahrenheit) hotter than normal.

"I have never seen so much snow that has melted on the south peak as this summer," says Gunhild Ninis Rosqvist from Stockholm University in Sweden, who is also the head of the Tarfala research station at Kebnekaise.

Measurements taken by Rosqvist and her team showed the southern peak measuring 2,101 metres (4,895 feet) above sea level on the 2nd of July. By the 31st of July, the height was only 2,097 metres (6,880 feet) above sea level.

The northern peak meanwhile, without the ice covering, stands at 2,096.8 metres (6,879 feet) above sea level. That 20 centimetres difference (7.9 inches) might well have disappeared since the last readings were taken.

"It's going very fast now," says Rosqvist. "The result of the hot summer will be a very big loss of snow and ice in the mountains."

The peak heights are measured using a differential GPS system, built on top of regular GPS, which is accurate to two centimetres (0.79 inches). Historic measurements have been recorded since 1880.

As temperature records continue to be set all across the world, Scandinavia has been under a persistent high-pressure anomaly. Research suggests this particular heatwave has been made twice as likely by the ongoing effects of climate change.

The hot and try weather has also caused outbreaks of wildfires in Sweden and its neighbouring countries, with blazes stretching way above the Arctic circle.

And this isn't just a recent phenomenon either. Records are being smashed year after year as the planet warms up, the kind of weather extremes that are consistent with climate change caused by an increase of greenhouse gases in the atmosphere.

The next measurements of the peaks of Kebnekaise are going to be taken at the end of summer when the melting period should be over. With these kind of temperature extremes though, it seems as though the old rules don't apply any more.