SMHI will update the normal period for climate data every ten years in the future, instead of every 30 years as hitherto. It is an adaptation to climate change, says climatologist Sverker Hellström, SMHI.
– To change only every 30 years, it is not really adapted to the fact that temperature and climate change faster than you thought then, 80 -90 years ago when it started, says Sverker Hellström, climatologist SMHI.
In order to be able to compare climate data, the values must apply to the same time period. When SMHI assesses what is normal weather, comparisons are made over a 30-year period, which is called a normal period. Now the normal periods must be updated more often.
The current one The 30-year period 1991-2020 is soon over. The following normal period from 2021 will be updated in 2030, so it will not be until 2050 as it would with the system so far:
– The difference is that so far we have changed every 30 years. But from now on, yes 2030, we will update again so it will be every ten years from now on.
This is an international decision of the World Meteorological Organization. The current normal period, which thus ends at the turn of the year, is expected to show that many months in the last ten years have been warmer than the normal period before, the years 1961 -1990.
In practice, the new arrangement will be marked by some statistical leaps, which you need to know, says Sverker Hellström:
– The most obvious is that there will be fewer months that are warmer than normal, and a few more months that are colder than normal. At least for a start after we change the normal period. There will be a little hope there that way.
But it is not just the normal period used to study the climate. But you can look at the average temperature for each month and each year back. It is actually independent of which normal period you use.
Source: ICELAND NEWS