Temperature trends: the Netherlands and worldwide, 1906-2013

Temperature increase in the Netherlands continues unabated

The annual mean temperature in the Netherlands has steadily increased and is now 1.5± 0.5 ^oC higher than 100 years ago. This is a statistically significant warming. There has been an increase of about 0.03 ^oC a year over the last 20 years.

Temperature increased in every season in the Netherlands

This warming varies according to the season. Most warming over the last 100 years was seen in the spring and summer, and least in the winter:

• Warming in spring: 1.7 ± 0.8 ^oC
• Warming in summer: 1.9 ± 0.7 ^oC
• Warming in autumn: 1.3 ± 0.6 ^oC
• Warming in winter: 1.1 ± 1.2 ^oC.

Heat records

Comparing the annual mean warming for central Netherlands in 2013 with other years between 1906 and 2012, we see that 2013 was relatively cold. The coldest year since 1906 was 1919 with a mean temperature of 8.1 °C. The seasonal values in 2013 were rather average, except for spring. Spring 2013 was very cold with 7.3 °C. It was the coldest since 1984 (the coldest spring since 1906 was 1958 with 7.0 °C). Spring 2013 was remarkable because the spring usually contributes most to annual warming. In the period since 1990 there have been eleven years with a spring temperature above 10.0 °C and two years with a temperature even above 11.0 °C. The warmest years in the Netherlands were 2006 and 2007 with a mean temperature of 11.1 °C.

Global temperature also increasing

The global temperature has increased steadily over the last 100 years by 0.9 ± 0.1 ^oC. This temperature increase is therefore statistically significant.
The global deviation from the annual mean temperature was relatively high in 2013: 0.49 ^oC compared with the 1961-1990 period. The year 2013 was therefore the eight warmest year since 1850. The year 1998 was the warmest, and the 8 warmest years all took place after 1997.

The Netherlands warming much faster than rest of world

Until now, it was expected that the Netherlands would warm at about the same rate as the world average. After all, the Netherlands is situated at mid-latitudes and affected by both land and sea climates. However, the Netherlands has warmed more than twice as much as the rest of the world since 1950 (Oldenborgh et al., 2003; 2009). This more rapid warming is probably not due to natural variations, but to the fact that land masses warm more quickly than oceans. In addition, the Netherlands has - as have other parts of Western Europe - been affected by more westerly and south-westerly winds in the late winter and early spring, reduced cloud cover, rising North Sea temperatures and an increase in the amount of solar radiation (due to cleaner air) in the spring and summer (PBL 2012).