|Above: Sad, dried sunflowers in a field near Magdeburg, eastern Germany on July 26, 2018. An intense heatwave and drought that has hit northern Europe this summer was made at least 2 – 5 times more likely at some locations by climate change, according to a preliminary analysis released on Friday by the World Weather Attribution network. Image credit: Tobias Schwarz/AFP/Getty Images.|
The intense, unrelenting heat wave that has gripped northern Europe during the summer of 2018 was made at least 2 – 5 times more likely at some locations by climate change, according to a preliminary analysis released on Friday by the World Weather Attribution network. This network, staffed by a team of scientists from six institutions, was established to provide near-real time analysis of how climate change might be affecting extreme weather events. The scientists used data from seven weather stations in Ireland, the Netherlands, Denmark, Sweden, Norway and Finland; a UK station was not included, due to time constraints.
The study found that rising global temperatures have increased the likelihood of the summer 2018 heat wave by five times in Denmark, three times in the Netherlands and two times in Ireland. The data for Scandinavia was too noisy to determine a specific number, with the report concluding “climate change increased the odds of a heat wave as observed in 2018 in Scandinavia but we cannot quantify by how much.”
The study focused on individual stations, not on larger areas like previous attribution studies have. A climate change signal is harder to distinguish from the noise in observations taken at individual places, meaning that the numbers quoted are likely to be low. This underestimate may be as much as a factor of two, since a study the same group did of the 2017 southern Europe heat wave found “an increase in the occurrence likelihood of a heat wave like the one observed was at least a factor two larger in the area average than at individual stations.” CarbonBrief has a more in-depth look at the study.
The results of the attribution study are not a surprise, since the increasing frequency and intensity of heat waves are among the most obvious and well-documented effects of climate change. If we continue to avoid making a concerted effort to reduce our emissions of heat-trapping greenhouse gases, heat waves as extreme as this one will simply be ordinary summer weather a few decades from now.
|Figure 1. Intense drought has gripped much of northern Europe in July 2018. Drought conditions have worsened in the affected area in the 2½ weeks that have passed since these conditions on July 1 – 10, 2018 (above) were observed. The UK saw its driest first half of summer on record, between June 1 – July 16. “This is the most severe drought we’ve had in 50 or 60 years,” said Niels Lindberg Madsen, head of EU policy at the Danish Agriculture and Food Council, in an interview with Politico. “Yields are very low simply because there has been no rain, generally speaking, for a couple of months.”Image credit: European Drought Observatory.|
Another day of extreme heat in northern Europe
The great northern European heat wave of 2018 continued to set all-time records on Friday, July 27, with Norway bearing the brunt of the record heat. According to weather records expert Maximilliano Herrera, dozens of all-time heat records fell at stations with a long period of record (POR) in Norway, some falling by a remarkable 4°C (7°F)—a very rare margin to break an all-time heat record by. Mr. Herrera, along with weather records experts Etienne Kapikian and Michael Theusner, have put together the following list of stations that set notable all-time heat records July 25 – 27. These stations had at least a 40-year period of record (POR).
Norway (a very partial list, with just the most important records):
Oslo Blindern 34.6°C (94.3°F) July 27, all-time heat record.
Stavanger 34.4°C July 27, all-time heat record.
Sauda 34.1°C July 27, all-time heat record.
Asker 34.0°C July 27, all-time heat record.
Sarpsborg 33.5°C July 27, all-time heat record.
Melsom 33.4°C July 27, all-time heat record.
Hamar 33.0°C July 27, all-time heat record.
Trondheim Airport 33.0°C July 27, all-time heat record.
Orsta 32.5°C July 27, all-time heat record.
Stavsberg 32.4°C July 27, all-time heat record.
Bergen 32.2°C July 27, all-time heat record.
Floro 31.0°C July 27, all-time heat record.
Tryvasshogda 31.0°C July 27, all-time heat record.
Haugesund 30.6°C July 27, all-time heat record.
Slatteroy 30.2°C July 27, all-time heat record.
Sogndal 29.6°C July 27, all-time heat record.
Fet I Eidfjord 29.4°C July 27, all-time heat record.
Boppard 38.8°C (101.8°F) July 26, new national monthly record for July and second highest temperature ever recorded in Luxembourg. Previous July national record was 38.0°C at Nittel in 2015.
Arcen AWS 38.2°C (100.8°F) July 26, tied Netherlands national heat record for July. KNMI regards the 38.6°C (101.5°F) at Warnsveld in August 1944 as the official all-time Netherlands heat record, but this is considered unreliable, and the 38.2°C reading from Arcen AWS is tied for the highest reliably measured temperature on record in the Netherlands.
Amsterdam Schipol Airport 35.7°C July 27, all-time heat record. Previous record of 34.8°C was set the day before.
Rotterdam Airport 36.1°C July 26 and July 27, all-time heat record.
Gilze Rijen 37.6°C July 26, all-time heat record.
Leeuwarden 34.8°C July 26, all-time heat record.
Volkel 36.9°C July 26, tied all-time heat record.
De Bilt (over 200 years of data) 35.7°C July 26, tied all-time heat record
Hoek van Holland 37.9°C July 27, all-time heat record.
Vlissingen 36.8°C July 27, all-time heat record.
Eindhoven 36.7°C July 27, all-time heat record.
Vieland Island 33.3°C July 27, all-time heat record.
Le Goeree 31.4°C July 27, all-time heat record.
Lelystad 35.1°C July 27, all-time heat record.
Deelen 24.4°C July 27, all-time highest minimum temperature for Netherlands.
Antwerpen 37.2°C (99°F) July 27, all-time heat record. Previous record of 36.7°C was set the day before.
Gent 38.2°C July 27, all-time heat record.
Beauvechain 35.8°C July 27, all-time heat record.
Gent 24.7°C July 27, second highest minimum in the history of Belgium (record: 24.8°C in July 2015 at Biarset).
Lingen 37.8°C (100°F), all-time heat record.
Geldern-Walbeck 37.6°C, all-time heat record.
Emden 34.6°C, all-time heat record.
Borkum 34.2°C, all-time heat record.
List aut Sylt 32.8°C, all-time heat record.
At least nine other stations with a POR of at least 40 years set all-time heat records for the month of July on July 26.
Lille 37.6°C (99.7°F) July 27, all-time heat record.
Copenhagen Airport (Kastrup) 31.7°C (89.1°F) July 25, previous was 31.4°C in August 2012.
Helsingborg 32.6°C (90.7°F) July 25, all-time heat record. Previous record 32.5°C set in August 1975.
Falsterbo 30.8°C (87.4°F) July 25, all-time heat record. previous record 30.2°C in 1994.
Satenas 32.8°C (91.0°F) July 27, all-time heat record.
Karlstad 32.1°C (89.8°F) July 27, all-time heat record.
|Figure 2. Record-warm temperatures in the Baltic sea in July 2018--as much as 8°C (14°F) above average in the northern portion--have allowed unusual phytoplankton blooms to occur, like this one in the Gulf of Finland from July 18, 2018. The blooms have led to beach closures. Image credit: NASA Earth Observatory.|
The forecast: extreme heat continues for northern Europe
Some relief in is sight on Saturday for northern Europe, as a moist flow of air from the southwest brings thunderstorms to much of the region. However, the latest long-range forecast for Europe from the GFS and European models predicts that the high-pressure ridge responsible for the northern European heat wave will remain locked in place through at least August 1, and some of the all-time heat records set over the past few weeks are likely to be broken again during that period. The European model predicts a gradual weakening of the ridge beginning on August 2, but the GFS model does not go along with idea, and it may be well into August before northern Europe sees an end to the heat wave.