An analysis by Dutch weather service MeteoVista (Dutch report | English coverage), using tens of thousands of meteorological measurements (by KNMI, the Royal Netherlands Meteorological Institute) shows the climate in the Netherlands has warmed by 0.42 degrees Celsius over the last decade, with climate figures averaged over the periods 1971-2000 and 1981-2010 (with November and December 2010 not yet taken into account).
Dutch warming over twice as fast
This is more than twice as fast as the global average that NASA Goddard Institute for Space Studies recently placed at around 0.2 degrees of warming per decade. [Other global estimates are somewhat more conservative - comparing with these the Dutch warming could be 3 of 4 times the average pace.]
Oceans vs. land
The geographical location of the Northwest European country may serve as an explanation for the speedy temperature rise. Warming tends to be faster over the Earth’s continents than over the oceans (although Dutch weather is in fact influenced by the relative proximity of the Atlantic).
Another reason is presumed Arctic albedo effects. The Netherlands lie around the 52nd degree northern latitude, that for instance also touches the southern shores of the Hudson Bay in Canada, polar bear territory. Decreased ice cover over the Arctic (in summer) and decreased snow coverage in for instance Canada and Siberia (in autumn and spring) serve as a positive feedback on climate change in much of the northern hemisphere.
Apart from getting hotter (especially in spring, summer and autumn), the Dutch climate has also become wetter and sunnier.
Especially winter rains and August downpours have increased. Spring and June are relatively dry and sunny.
Less fog, more sunshine
Overall sunshine has increased considerably, by as much as 15 minutes per average day. This is attributed to environmental policy in the Netherlands and surrounding countries since the seventies, decreasing soot and other aerosol emissions from heavy industry and thereby decreasing fog and low stratus cloud weather conditions.
This should not be interpreted as a driving factor to the measured temperature rises – as the increased clarity of the Dutch skies leads to cooler nights, compensating a slight additional increase in daytime temperatures (the difference between hotter days and cooler nights is marginal, <0.1 degrees C).
(c) Rolf Schuttenhelm | www.bitsofscience.org