Climate indicator - Temperature

The climate is getting warmer. Since 1988, all years but two have been warmer or much warmer than the average for 1961-1990. The warm-up is due to increased emissions of greenhouse gas. How big the warm-up will be, depends on how successful people are in limiting the emissions. A higher temperature also effects other characteristics of the climate, such as evaporation and precipitation patterns.

Comment on the result

When Swedish temperature rates are compared to the global ones, it is noticeable that they may differ. This is due to the fact that Sweden only constitutes for a small part of the earth’s surface. Among other things, we can see that the warmest period during 1930s to 1940s and years with very cold winters during 1939/1940 and 1941/1942, are not very prominent in global data.  2010, which was a cold year for Sweden, is an example of a regional deviation as this year was warm globally. Otherwise there are great similarities between the global and the Swedish variations in temperature. One example is that the end of the 19th century was colder then the average for the 20th century.

Since 1988 each year, except 1996 and 2010, has been warmer or much warmer than the average for the period 1961-2010. The up-warming is in line with what is expected due to the greenhouse effect.

The increase in Sweden’s mean temperature is close to 2 degrees compared to the end of the 19th century. The corresponding value for the global mean value is approximately 1 degree.

Various seasons

When studying the development in temperature during the different seasons, there has been a trend with rising temperatures for all seasons. However, this is clearer during spring time. This could be an interaction, where reduced spreading of ice and snow means that the heat of the spring sun can be converted more quickly into heating the air.

When it comes to winter, we can see that there has been a variation between both warm and cold winters over time. However, the number of really cold winters have decreased since around 1990.

Similar variations in the global average temperature

In general there are many similarities between the variations in the global and the Swedish temperature, for example the end of the 1800s was colder than the 1900s. Since 1988, all years except 1996 and 2010 have been warmer or much warmer than the average for 1961-1990, which is the normal period currently being used. This is in line with the consequences of an increased greenhouse effect.

Why is this indicator important?

When talking about climate change,  first and foremost it is the temperature we think about. The increasing amount of greenhouse gas moderates the outgoing heat radiation from the earth’s surface, while the incoming solar radiation is not affected. This leads to an increased temperature. Observations of temperature show that the mean temperature rises everywhere in Sweden in line with what climate models show.

In the future, we can count on further warming and an increased risk of various extreme weather-related events, such as heat waves, torrential rain and drought. In Sweden, the average temperature during the year is increasing approximately twice as fast as the global average. This can lead to serious consequences for humans, animals and plant life.

Extremely high temperatures can, for example, affect human health, ecosystems, agriculture, forestry, transport on land, water, in air, and more.

How has the indicator been calculated?

The yearly temperatures in the diagram for Sweden are based on observations since 1860. Data has been corrected for clear errors and missing data has been filled in.

Over the years, many stations have changed instruments and measuring methods and sometimes even moved to another location. In order for the temperature series to be considered as if it had been measured from the same place with the same instruments and methods at all time, the time series has been homogenized. This means that differences that may arise when changing instruments, measurement methods or moving the location, have been taken into account.

In order to calculate the climate indicator temperature, we have calculated an average of approximately 450 time series.

Future temperatures

The average temperature in Sweden is expected to continue to increase. By the end of the century, the average annual temperature will be 2–6 °C higher than during the period 1961–1990, depending on how much greenhouse gas emissions continue.

The temperature is expected to increase during all seasons, but mostly in northern Sweden in winter. Winter is also the season when the variation between individual years is greatest, meaning that in the future we will also experience winters that are both significantly warmer and colder than the average climate.

Read more about the future climate.