To green and to blue

Let our political imaginations soar Leaves for German and international politics 10/2025 Gaza and the age of impunity; Islamism and leftwing anti-Zionism; dead-ends of statecraft; illiberal rap. A big surprise at the end of June 2026 in politics: a heatwave! Climate change – huh? Saarland, Saxony-Anhalt, and Brandenburg experienced new heat records of nearly 42 degrees. With almost 30 degrees followed the warmest night since the start of weather observations. Families could no longer sleep in overheated attic rooms, hospitals were completely overloaded, asphalt broke up, livestock and farm animals died, young birds fell from hot nests and died, Europe recorded thousands of heat deaths. The World Health Organization warned: "Europe is the fastest-warming continent on Earth – warming is happening twice as fast as the global average." But there was hardly any reaction from the federal government, and certainly no empathetic one. In the air-conditioned Chancellery, Federal Chancellor Friedrich Merz found compassionate words shortly thereafter for the German football team who were eliminated from the World Cup, but not for suffering old people, the sick and children, overloaded paramedics and nurses. When asked whether heat protection should be a matter of leadership, government spokespersons Stefan Kornelius replied that the statement was "not yet a solution to a problem." In fact, the municipalities are responsible for heat protection plans in federal Germany. But they are being overwhelmed by the federal government with new tasks over the years, without receiving more money for it. The obvious consequence: many are in debt, and there is no money for climate protection and climate adaptation. Hospitals, schools, kindergartens, and nursing homes do not receive sun protection or air conditioning or heat pumps that can cool in the summer, not even in new buildings. Furthermore, municipal decision-makers seem to like to avoid the fear of climate change as soon as summer is over. Yet, there are so many creative ways to cool cities and rural areas that must finally be taken up. Many still believe that global warming and its tangible consequences can be stopped by renewable energies alone. Stopping the burning of fossil fuels is undoubtedly extremely important, but CO2 reduction is not everything. Every day, land is destroyed to build roads, buildings, and industrial facilities on it. Old forests are cut down to establish soy or palm oil monocultures. Landscapes are being drained, rivers straightened, peatlands dried out, soils compacted with heavy tractors and treated with chemical fertilizers and pesticides, destroying the finely tuned structure of large and small soil pores. Water is being transported out of landscapes as if it were a pollutant instead of being kept in the soil. This deprives nature of the ability to absorb heavy rainfall and store it for periods of drought. A landscape without vegetation cannot evaporate water anymore, and its dried-up soil can no longer store it; it becomes a desert. If it rains at all, the precipitation flows away quickly, leads to floods, and ultimately ends up in the seas. A 2025 study shows that large amounts of soil water and moisture were lost worldwide between 2000 and 2015 – which also contributed to rising sea levels. It is particularly critical that dried-up soils regenerate very slowly. This shows that soil moisture is a central, hitherto greatly underestimated factor in the global water and climate system. About half of the droughts in East Germany are caused by poor land and water management, explains the hydrobiologist and lead water researcher at the Helmholtz Centre for Environmental Research in Magdeburg, Professor Dietrich Borchardt: "The natural function of the land as a water reservoir is increasingly being lost. Over the centuries, we have caused a gradual outflow, significantly lowering groundwater levels, mainly due to the management of fields and grasslands." Land and the continent are slowly but surely drying out – unless counteracted finally. Have you ever experienced that it is much better to be in the shade of a large tree on a hot day than under an umbrella? That it is cooler under foliage than under fabric? This is because the umbrella does not manage photosynthesis. If we imagine the Earth as a living planet, then rivers are their veins and trees are their sweat glands. Plants consume water and thus provide evaporative coolness, clouds, and new precipitation. This cools our Earth to an enormous extent and keeps its large and small water cycles in motion. A single large tree evaporates about 400 liters on a summer day, with a cooling effect comparable to that of ten air conditioners. Furthermore, it catapults bacteria, pollen, spores, and organic compounds into the air, to which water molecules attach. Water becomes clouds, which rain and in turn keep the earth, soils, and vegetation alive. These lower clouds also reflect incoming solar radiation in a wonderful way. Solar energy is partially radiated directly into space – direct climate protection. About half of the precipitation over the continents comes from the land itself and not from the sea, depending on the geographical location. In essence, rain does not fall from the sky but is also generated in the soil, in addition to the seas. Therefore, we can reverse some of the land heating by greening and "greening." Through humus accumulation and continuous vegetation on fields and grasslands, reforestation, forest restructuring, rewetting of peatlands and wetlands, de-paving, and more. "Greening" and "Blueing" are much more than climate adaptation; they are direct climate protection. A few examples may illustrate this: Reforestation in Europe since the 1980s has demonstrably contributed to cooling according to a 2024 study. In Central Europe, temperatures dropped by about half a degree on average, and even by up to 1.9 degrees in heat periods. The reason for this is mainly increased evaporation, which promotes cloud formation and reduces heat stress. A 2024 study shows that the US East Coast has cooled despite climate change because the forests there have been reforested since the 1920s or have allowed to regrow on former agricultural lands. This landscape is a huge "cooling spot" in the midst of a nation that is otherwise heating up. The soil there is, on average, one to two degrees cooler and even up to five degrees on hot days. Renatured forests thus act as the planet's air conditioners. A model calculation for the drought-prone Elbe-Elster district in Brandenburg shows that more trees and wetlands could reduce the surface temperature there by up to 3.5 degrees, thus locally contain global warming. Such measures are almost everywhere implementable and were initiated by the former Federal Minister for the Environment Steffi Lemke (Green) with the "Action Plan for Natural Climate Protection" (ANK). The program is still running until 2029. With a budget of around four trillion euros, peatlands, wetlands, and river floodplains are to be rewetted, dikes relocated, forests, meadows and coasts renatured, and "sponge cities" promoted, which absorb precipitation like a sponge and release it as cooling in drought periods. This is a milestone in climate policy. The implementation of the ANK is however slow: a part of the funds has not yet been released, for example because the funding conditions for poorer municipalities were insufficient and they cannot provide the co-payments. According to the Federal Ministry for the Environment, now led by the SPD, up to the beginning of 2026, a total of almost 1300 projects have been approved, most of them in the area of "climate-adapted forest management." 156 projects are to protect and rebuild peatlands, 97 measures to promote water retention. Only three projects were for the development of "sponge cities" and only one for dike relocation. It is also completely unclear what will happen after 2029 – the lack of reinforcement of work by permanent local "caretakers" is one of the biggest structural problems of the program. The rewetting of peatlands, forest restructuring, and the renaturation of lakes and floodplains are particularly climate-effective according to an evaluation of the ANK program. They cool entire landscapes through evaporation and have further positive side effects such as biodiversity protection and CO2 storage. In cities, green spaces with trees belong to the most efficient cooling methods according to a study by ETH Zurich. However, according to the German Environmental Action group, almost a million city trees along with their cooling effect have been lost since 2018 – mainly through deliberate felling. Even if a new tree were planted for every tree, it would take decades for it to take over the function of the old one if it survives in hot summers due to lack of sufficient care and insufficient watering. The credo today must therefore be everywhere: Leave healthy, large trees! According to a Lancet study, EU cities are, on average, covered by tree canopies by 15 percent. If this stock were to double, the number of premature heat deaths could decrease by 40 percent. Urban climate research clearly shows how to cool the microclimate in the summer remarkably well. This is helped by: de-paving, fresh air corridors, parks, avenues, mini-forests, city trees, urban gardens, green facades, pergolas, alleyways, green roofs, moss walls, water fountains, renatured rivers, ponds and pools. The new guiding principle for this is sponge cities. This is based on the Chinese architect Yu Kongjian, who conceived the concept in the late 1990s and applied it to the flood-plagued metropolis Wuhan in 2012. Copenhagen adopted the concept and created large areas after the flood disaster in 2011 to store rainwater and prevent floods. The "Climate Quarter" of the district Østerbro is climate-resilient with its green roofs and "rain gardens." "Rain gardens" are planted infiltration surfaces as part of a sponge city. Up to three times more water can infiltrate in rain gardens than in a lawn. Rain gardens also filter the air, provide food and nesting sites for birds, insects, and small mammals, and water the vegetation. Green roofs are also part of the sponge city concept: they can store up to 80 percent of precipitation and slowly release it through evaporation. An earth and plant layer on a previously stabilized roof stores water and simultaneously protects indoor spaces from extreme outdoor temperatures: in great heat, green roofs have a cooling effect, and in winter, they are insulating and warming, saving heating costs. De-paving is also extremely important because asphalt and concrete radiate heat like ovens in densely populated cities. In practice, however, a total of 51 hectares are still paved daily across the country for new roads and buildings. Furthermore, the recently passed "Infrastructure Future Law" is moving in the wrong direction: it protects highways rather than floodplains. There is another way: in the Netherlands, for example, the "Tegelwippen" movement has emerged, meaning "tile-flipping": over 200 municipal initiatives compete with each other to free as much land from paving as quickly and as much as possible. Under civil society pressure, Berlin, Hamburg, and other metropolises have also begun to transform into "sponge cities." To avoid a popular or "tree decision," the Berlin House of Representatives decided in late 2025 on the "TreesPlus Law": by 2040, a million street trees are to be planted, a thousand mini-parks created, and every felled tree replaced by three new ones. However, the "Tree Decision" movement criticizes the lack of official support and the unclear financial arrangement for maintenance. In the Carl-Legien settlement, for example, the district office took action against a residents' initiative that had planted two trees in front of the facade for heat protection. In Hamburg, the municipal operation Hamburg Wasser is building huge wastewater highways and reservoirs under the city, which retain rainwater when it overwhelms the treatment plants and sewer system. In 2025, the environmental authority called for a competition "De-paving: from Grey to Green" based on the Dutch model. Public participation was very active with over 2200 ideas, but only a dozen have been implemented so far. German authorities still act with bureaucracy and control madness in doubt, rather than trusting an active citizenry – which would reduce costs and social anger. Finally, regenerative agriculture also plays a key role in climate stabilization. It builds soil, converts CO2 into carbon, binds it, and stores massive amounts of water. It works with the avoidance of plowing, cover crops, agroforestry, hedges, and flowering strips, as well as the addition of compost and biochar. All this allows biodiversity and healthy food to thrive, a win-win situation. Many farms already practice this. Others are participating in regenerative measures within the framework of developing "climate landscapes" and "sponge regions." Perhaps the most ambitious project here is "Regenerate" on Lake Constance. This German-Swiss-Austrian border region is characterized mainly by conventional fruit and wine cultivation. "Regenerate" wants to contribute to reshaping this into a climate landscape – together with farmers, municipalities, gastronomy, retail, researchers, and regional networks. The growing team, financed by donations from private individuals and foundations, has now reached over 300 farmers with hundreds of hectares of land in the region. The goal is to create living cycles, fertile soils, and diverse and thus resilient farms. Every female farmer and gardener is accompanied and supported on the way with advice and further training. Peatlands, wetlands, and river floodplains have been destroyed, filled up, or drastically reduced everywhere in recent decades, yet they are essential for stabilizing the water balance and climate. Volker Zahner, a wildlife ecologist at the University of Weihenstephan, is convinced that beavers could do great things for the water cycle. In a model calculation for the Isar region, one of his projects concluded that the water areas in the beaver area had risen by almost half, the groundwater level had increased by half a meter, and evaporation had also increased significantly. During droughts, beavers are additionally supported by volunteer fire departments and brand prevention departments. Beaver dams can even serve as fire breaks in megafires: an extensive beaver structure contains, according to a US study, over four million liters of water and stores another 25 million in the subsurface. If the German lands had not been extensively de-beaveraged, there might not have been many forest fires in the first place. Rodents were almost exterminated in Germany, but now about 40,000 of them live again, mainly in Bavaria as well as along the Elbe and its tributaries. What is good for this is shown by Czechia: while authorities and nature conservationists in the nature protection area Brdy planned a costly renaturation of a river course for many years, beavers created facts: in record time, a single beaver family built a dam that would have cost 1.2 million euros. "In the time, we didn't even get a building permit," laughs the head of the local nature reserve. All these examples show: Nature helps us if we help it. Published September 14, 2026 Original in German First published by Blätter (German original); Eurozine (English version) Contributed by Blätter © Ute Scheub / Stefan Schwarzer / Blätter / Eurozine PDF/PRINTSubscribe to know what’s worth thinking about. Gaza and the age of impunity; Islamism and leftwing anti-Zionism; dead-ends of statecraft; illiberal rap. Why forest restoration projects are counterproductive; how citizens are mobilizing to protect Europe’s woodland from the right; and why diversity is the solution to sustainable timber.