Reindeer in the Arctic, along with the herders who rely on them for income, have already begun to feel the effects of climate change.

The indigenous Sami people in Sweden say abnormal temperature fluctuations in the region have disrupted this year’s migration, according to NBC News.

Snow plays a key role in reindeer migration, and is crucial for herders’ ability to track their movement – but without snow, they’ve been forced to postpone their activities.

It isn’t just warm temperatures throwing a wrench in their plans this year, local herders say.

Instead, the region has experienced fluctuations above and below freezing so far, causing an unusual cycle of freezing and thawing.

While the Sami people typically corral reindeer over a two-week period in November, this year’s weather has gotten in the way.

‘Something is really wrong with nature,’ 37-year-old herder Niila Inga told NBC.

‘I can’t ask my father what to do now because he hasn’t seen this; it hasn’t happened during his lifetime.’

Reindeer herders gather the animals and kill them for meat during September, leaving the remaining reindeer to graze in the area until winter migration, according to NBC.

When the time comes for the reindeer to move, the herders follow them on snowmobiles. But, without snow, there’s no way for them to do that.

Sweden’s unusual weather comes as the World Meteorological Organization revealed 2018 will be among the hottest years on record.

According to the new WMO report, this year will sit at number four.

The findings also mean that ‘the past four years – 2015, 2016, 2017 and 2018 – are also the four warmest years in the series,’ the report says.

Experts warn we’ll likely fall short of warming targets.

And, the Arctic is often hardest hit by climate changes.

‘Greenhouse gas concentrations are once again at record levels and if the current trend continues we may see temperature increases 3-5°C by the end of the century,’ said WMO Secretary-General Patteri Taalas.

‘If we exploit all known fossil fuel resources, the temperature rise will be considerably higher,” he said.

‘It is worth repeating once again that we are the first generation to fully understand climate change and the last generation to be able to do something about it.’