Another record year
As was to be expected in an increasingly heating world, last year broke several heat records. According to reanalysis data provided by the European Centre for Medium-Range Weather Forecasts (ECMWF), 2018 was the warmest year since 1900 for millions of Europeans living at the center of the continent. Over two hundred cities and their surroundings saw record-breaking temperatures, from Montpellier in southern France to Białystok in north-eastern Poland. Cities along the Danube, around the Adriatic Sea and central Italy also count 2018 as their warmest year to date.
Even the cold spell of March 2018, which sent temperatures below 0°C in much of the continent, including snow in southern cities such as Rome, was not that cold. Such events are due to a weakening of the polar vortex, a low-pressure area that normally stays over the Arctic. As it becomes unstable, it can move south, as it did in March 2018 over Europe or in January 2019 over the United States.
However, that such cold snaps are deemed newsworthy has more to do with their rarity than with their exceptional strength. The interactive visualization below shows how many episodes were at least as cold and at least as long as the coldest week of 2018, by decade. In all but a handful of cities, cold spells were more frequent in the 20th century.
2019 could be next
An analysis of the first five months of 2019, using another data source, this time from European Climate Assessment & Dataset project, which uses station data, shows that the records of 2018 could be broken soon. From January to the end of May, some cities saw temperatures that were much higher than the average for the period from 1970 (starting in 1975 for Lyon) until 2000. Warsaw, Cluj and Tallinn were about 2.5°C hotter in 2019 than it was at the same period in the late 20th century. Helsinki, Cracow and Malmö passed the 2°C mark. Only Spanish cities such as Bilbao and Palma de Mallorca were less than 0.5°C hotter in the first third of 2019, compared to the late 20th century.
The numbers for 2019 are only preliminary. The European Data Journalism Network will update its One Degree Warmer project in early 2020 with ECMWF data, which will allow for comparisons across time.
Hotter temperatures continue to disrupt the way of life across the continent. The warm winters of 2017/18 and 2018/19 prevented several ice- or snow-related events from taking place. In the Netherlands, the Elfstedentocht or “eleven cities race”, an ice-skating competition that has existed since the 18th century, could not take place (the race was last run in 1997).
Animal life is also impacted. In the Baltic sea, which researchers consider, due to its rapid heating, a test bed of what is to come in other oceans, herrings have become rarer. Instead, fishers have begun to bring back sardines – a staple of the Portuguese cuisine – ashore. While this provides for temporary relief, the long-term prospects of the Baltic fishing industry are bleak.
The hot temperatures of the spring and summer 2018, combined with a lack of rain, led to crop failures in Germany and Poland. The total cost has been estimated at 3.5 billion euros. Warmer winters also make the effect of short freezes more severe. Sub-zero temperatures in April or May in eastern Germany and Poland, as happened this year, can ruin the cherry or apple crops. Although such freezing nights were not rare in the past (the “Ice Saints”, a proverbial date for the last possible frost of the winter, are in mid-May), the fact that trees blossom much earlier due to warmer Februaries and Marches compounds the damage.
Some heat-induced casualties are more severe.
Dozens of Europeans died of dehydration and heat strokes during the 2018 heat waves, but no central authority keeps track of exactly how many died. Deaths from heat waves are probably massively underreported. EM-DAT, a database of natural and technological disasters maintained by the catholic university of Louvain (Belgium) and one of the few references used by experts in disaster forecasting, only contains seven entries for the 2018 heat waves. Of these, only one contains a number of casualties (9 deaths in Spain last August). While the cause of a given death can be difficult to establish with certainty, the few statistics offices that do publish numbers for “heat-induced deaths” acknowledge that heat waves kill much more widely. In Baden-Württemberg, a German region of 11 million, heat-induced deaths number over a thousand each year, reaching two thousand when heat waves are especially acute. A study published in 2017 in the Lancet assessed that between 10,000 and 60,000 Europeans currently died of heat each year. However, this study was only an extrapolation based on climate trends and data anterior to 2010.
Adaptation is slow
Urban areas, which are home to three in four Europeans, are at the forefront of the climate breakdown. Concrete and tarmac store heat during the day and release it at night, contributing to a phenomenon known as “heat islands,” which makes cities a few degrees hotter than their surroundings. For many of their dwellers, especially those too poor to invest in cooling equipment such as air conditioning, the adaptation policies of local government are, quite literally, a matter of life and death.
Some cities take adaptation seriously. Münster, a city of 300,000 in western Germany, declared a climate emergency in May 2019, following in the footsteps of Bristol, which did so in autumn 2018, London, Constance and others.
While the declarations of climate emergency are too fresh to be assessed, a flurry of other programs have tried to address the problem since at least the mid-2000’s. Some 15 cities of the European Union have or plan to have a “chief resilience officer” (CRO), under the “100 resilient cities” program, which is financed by the Rockefeller Foundation (it paid two years’ worth of the CROs’ salaries).
In Paris, for instance, where the temperature in 2018 was 2°C hotter than in the 20th century, the CRO launched a program to redesign the courtyards of the city’s 700 schools in order for them to limit the heat island effect. The city is also thinking of transforming its inner-city highway, locally known as the périphérique, into a regular boulevard.
In light of past efforts, one can ask how sustainable such programs are.
A survey of 61 cities in six countries by the European Data Journalism Network showed that adaptation strategies are, at best, uneven.
Lisbon, which is also part of the Rockefeller Foundation’s “100 resilient cities”, provided great details about its Climate Change Adaptation Strategy (EMAAC in its Portugese acronym), a plan the local administration drafted as part of the ClimAdaPT.Local project, a €1.5m effort subsidized by the European Economic Area.
La Spezia, a city of 90,000 in western Italy where 2018 was close to 2°C hotter than the 20th century average, wrote that part of its strategy was to be a member of Mayors Adapt, a network of local administrations set up by the European Commission. However, the program ceased to exist in 2015 (its successor program is called “Covenant of Mayors”).
The link between official programs and concrete effects was thin in other cities.
From 2008 to 2014, the German government supported pilot projects, under the program “Klimzug”, to help seven regions draft plans to adapt to the climate breakdown. Dresden, a city of 800,000 in eastern Germany where 2018 was 2.5°C hotter than the 20th century average, answered EDJNet’s survey by referring to its Klimzug plan (which goes by the acronym of Regklam), which seems to be followed upon and implemented. Another city which benefited from a Klimzug pilot was Rostock (200,000 inhabitants, on the Baltic coast). The local administration answered our survey without referring once to their Klimzug strategy, named Radost. Ironically, although they answered the survey by claiming that Rostock had benefited from hotter temperatures, a heat wave struck the city a few weeks after they sent back their answers. They then admitted to the local media that they were “woefully unprepared” to deal with such events. Interestingly, within the Radost program, Rostock made a commitment to design a heat wave mitigation plan. That was in 2014.
“We only manage emergencies”
The EDJNet survey asked city officials what studies had been conducted to assess the effects of hotter temperatures on the population.
Skövde, a city of 30,000 in south-central Sweden where 2018 was 2°C hotter than in the 20th century, explained candidly why it has not yet assessed the impact of the climate breakdown on its population: Politicians “usually have other priorities, such as economic growth, so that climate adaptation does not receive the same attention. Party politics sometimes does not really go the same way as scientific evidence,” city officials wrote (a study is in the works, they added).
The administration of Belluno, a city of 35,000 in northern Italy where 2018 was 1.7°C hotter than the 20th century average, claimed that rising temperatures were no problem – and also wrote that they had not conducted any study on the topic besides mosquito and tick monitoring, raising questions as to which facts were used in the aforementioned claim.
Such lack of any systematic assessment is problematic. In most countries, cities have to come up with adaptation plans or strategies, such as “action plans for sustainable energy and climate” (Paesc in its Italian acronym) in Italy or a “local plan for climate, air and energy” (Pcaet) in France. That so few have led any rigorous studies of the effects of hotter temperatures gives credence to the statement by Skövde officials: Such plans are probably dominated by political concerns rather than by evidence.
Treviso, a city of 85,000 in northern Italy, wrote that, while some studies had been done, they came out of personal initiatives. “Evidently, although it is now serious, the problem has not yet been perceived by the institutions in all its gravity,” wrote a city official. They summarized the problem by writing that they “only manages emergencies… always more frequently!” A sincere statement that, despite the mountains of adaptation reports that have been produced, could apply to Rostock and hundreds of other European cities.
The data we use
There are many ways to measure temperature. Most people are interested in the maximum daily temperature (usually measured two meters above ground), because it helps us decide what clothes to wear. Others, such as farmers, might prefer ground temperature readings. EDJNet uses the daily mean temperature, which is the average of the temperature measurements at midnight, 6am, noon and 6pm.
There are several sources of temperature data. Current temperature, such as the one displayed on a typical smartphone, usually comes from weather stations. However, such station data cannot be used for long-term analyses. Not all stations existed in 1900, and even if they did, they might have moved, or the microclimate around them might have changed (some stations that used to be in the countryside are now surrounded by concrete), making trends harder to follow. For these reasons, EDJNet uses so-called “reanalysis” data provided by ECMWF. Such data aggregates several data sources, including station data as well as measurements from satellite and weather balloons. Data from the first half of the 20th century is reconstructed using climate models and historical station data.
Reanalyses come from the world of weather forecasting. Geert Jan van Oldenborgh, a climate researcher at the Royal Netherlands Meteorological Institute who maintains the Climate Explorer, a collection of weather-related data sets, explained in an email interview that reanalysis exist to provide “the best initial state to start a forecast.” As weather models have gotten better and better, it makes sense to “use past observations to get the best possible description of the weather in the past,” he wrote. However, the reliability of reanalysis can vary. They are sometimes better than station data for whole countries, such as India, but can easily miss winter extremes at high latitudes, van Oldenborgh added.
ECMWF data is available for the whole world but its resolution is limited to squares of about 80 km on each side. Differences of several degrees might occur between the temperature readings reported by ECMWF and the actual temperature for cities which lie low next to mountainous areas, but the heating trend is generally the same, whether one uses reanalysis or station data. A major caveat to this approach concerns seaside cities where the sea heats faster than the land. This phenomenon happens mostly on the Baltic sea, where the heating rates reported by EDJNet are generally higher than those one would obtain from station data.