The flowering of, among other things, hazel and alder occurs earlier and earlier, something that will be felt during the pollen seasons.

- During the 20th century, we have no notes at all of hazel before New Year, but now it has happened many times during the 2000s.

So something is happening, says researcher Åslög Dahl in Morgonstudion.

In the video, Åslög Dahl explains why pollen allergy sufferers may have it tougher in the future.