The citizens of Portland (Oregon, USA) have been lifting and removing pavement since 2008. They do this to lower the local temperature (which can reach 40 degrees) and that year they organized a movement called Depave that has been gaining followers, even in other parts of the world. To date and according to different media, Depave has removed 33,000 square meters of pavement and in some areas, such as around Powell Butte, they have managed to lower the temperature by more than 10 degrees by replacing asphalt with vegetation. Another added advantage, say the movement, is that 83 million liters of rainwater have been absorbed and flooding has been avoided.
With temperatures in Spain exceeding 45 degrees these days, it is worth asking whether it might be a good idea to take measures to adapt to the heat, like those carried out in Portland. Cities are the most affected by high temperatures due to the heat island effect. Asphalt, concrete and dark construction materials absorb heat and release it, causing the thermometer to rise by up to 10 degrees compared to rural areas. In the world, cities like Jizan in Saudi Arabia, Athens, Mexicali (Mexico), Melbourne or Cairo Temperatures have reached almost 50 degrees, but in Spain the towns of the Guadalquivir Valley or the Levante have nothing to envy. This week the thermometers have exceeded 40º in several Spanish municipalities and the nights have not dropped below 25 degrees.
We are in the hottest period of the year and overcoming the second heat wave that has arrived just 48 hours after the first. “A ridge is once again located at high altitude, with an associated warm air mass, which will continue to warm up until Wednesday thanks also to high pressure and high sunshine. Wednesday will be the warmest day of this week and 40ºC will be exceeded again in some communities. In addition, tropical nights will gain ground again and in areas of the south and east they could be torrid,” announced “eltiempo.es” hours before the arrival of the second wave. In addition, they remember that to speak of a heat wave in Spain several requirements must be met: that the episode affects more than 10% of the territory and exceeds for at least 3 consecutive days or more the 95th percentile of the maximums of the period 1971-2000.
A normal June?
Until mid-July, it seems that the temperature has given us a break, the arrival of cold air masses from the Atlantic has helped to make this happen. However, Jorge Olcina, professor of Regional Geographic Analysis and director of the Climatology Laboratory at the University of Alicante (UA) warns that “The models say that hot weeks are coming. When summer began, it was said that it would be like the summer of 2022-2023 and if these forecasts are fulfilled, it means that the next few weeks, the rest of the summer, will be very hot. We will see the arrival of Saharan air and anticyclonic weather more frequently.
The researcher also points out that “the most affected areas will be in the south of the Peninsula in the Guadalquivir Valley. That is where records are always broken. However, where comfort is being lost the most is in the Mediterranean because the sea water does not allow the atmosphere to cool down. That is the trend; we are moving towards a less comfortable scenario, especially in summer and at night,” says Olcina.
This uncomfortable temperature is behind serious health problems. According to the Carlos III Institute, between 2022 and 2023 some 8,000 people have died due to heat. (so far this year we have almost reached 200). The heat that kills is not the daytime heat, in fact, heat strokes only account for 2 to 3% of the statistics. The harmful heat is the nocturnal and sustained heat, that is, not going below 23-24 degrees affects people who have heart problems or respiratory diseases, diabetes or mental illnesses.
In fact, the Ministry of Health has activated a new system of health alerts for heat that take into account epidemiological data beyond the maximum temperatures. “We tend to think that we are at risk when we are at 36 degrees, but for some cities, such as those in the north of the peninsula that do not reach such high temperatures, the increase in temperatures also poses a danger. It has been seen in Vigo that from 28 degrees there are already health problems, partly because they do not have as much heat culture as in cities that have suffered from it for decades and because the houses are not conditioned for the high temperatures that are recorded now,” clarifies Elvira Jiménez, spokesperson for Greenpeace.
Heat also causes dizziness and headaches, increases levels of pollutants and atmospheric ozone, has consequences for flora and fauna, and increases drought and the possibility of fires.
Adapt or suffocate
The measures being implemented in Portland may seem shocking, but in Spain, municipalities are also developing their actions to combat the heat. The NGO Greenpeace has just published the report “Adaptation in cities to extreme heat”, in which it analyses the adaptation plans of 15 Spanish cities to the heat. “If we look at global trends, we continue to break records (14 months of temperatures higher than average…). We may not have had a very hot June here, but in Italy records have been broken and in Germany there have been floods. This is the scenario that we must begin to live with. Much has been done to mitigate emissions, but it is necessary to adapt to the consequences of climate change that we are already facing,” says Jiménez.
The organization believes that it is necessary to act in cities and re-neutralize them to increase vegetation cover equitably between neighbourhoods (“they are often concentrated on the outskirts,” he says); enabling accessible and free public climate shelters or developing shade and comfortable travel plans. In addition, measures must be implemented to increase the protection of the most vulnerable people and plans to decarbonise homes must be implemented.
Among the plans studied, one of the most complete, according to the organization, is that of Barcelona, which already has more than 350 climate shelters or a “shadow city” plan. In other municipalities there are still challenges such as unifying measures under the umbrella of adaptation. “Perhaps the best-known action is that of plant cover and, in that sense, it must be said that many of the actions that can be carried out have positive consequences in other areas. For example, trees also help reduce the presence of pollutants in cities and increase soil permeability, reducing the possibility of flooding,” says Jiménez.