Article

How an ancient climate solution is cooling modern cities

The climate is changing, our Earth is becoming warmer. We are all worried. But can we do something about it? These are the questions we ask ourselves time and again. We often believe we need new high-tech inventions to deal with these problems – but sometimes the most effective solutions are those that have been around for millions of years.
In most parts of India, it is becoming difficult to go out in summers without proper cover
In most parts of India, it is becoming difficult to go out in summers without proper cover

Some people ask if planting trees actually makes a difference to the heat levels. I will tell you a story. I belong to a coastal city called Bhubaneswar, the capital city of the state of Odisha, in Eastern India. Given the proximity to the Bay of Bengal, there was always some amount of humidity in the air throughout the year. When I was a child, growing up in my hometown, I used to notice it was becoming harder and harder to go out and play in the sun, especially during summers. Many of us have heard their parents talk about things they used to do, which was no longer possible for us. But I am telling you, I experienced this change myself. During our childhood, our schools used to close down for one and a half months for the summer vacations. We spent the whole day playing and lazing around. When I was 7, I could still go out and play all day. But when I turned 11, that was no longer possible! What changed? The heat became unbearably painful in just a few years. You could hear on the news about people dying from heat strokes (we called them sun strokes). It was horrible! When I was younger, most people had only fans in their homes and only a few had air coolers. However, only a few years later, you could not live without an AC! Now I am 35. The heat is only getting worse in my hometown. So much so that, those summer vacations now sometimes last up to two and a half months because the heat is well nigh unrelenting. Last year, in 2023, the highest temperature recorded was 49 degrees Celsius! On top of that, summer vacations are limited to students. If you are working professionally, you get no vacations. Imagine commuting to work in that kind of weather! And I am not even talking of people who have to work in the sun. Let alone working outdoors, even 20 minutes out in this heat is enough to give you a heat stroke. Whenever I go back now, I prefer visiting the city during winter now because I know my body cannot take the scorching heat. The winters are no longer cold there either. The mornings are not even chilly. It is just a mild, temperate respite for two months from the killing heat the rest of the year around.
Dog lying on wet earth to cool itself - Indian summer heat
Dog lying on wet earth to cool itself - Indian summer heat

Why am I telling you this? So, there was this section in the city that is saved from construction and development, and this area is filled with trees on one side of the road, like a small jungle. Whenever you pass this area, you can feel an instant burst of coolness hitting you, for that stretch of the road. What does this prove? Trees, their presence or absence, do make a big difference. Our planet has myriad ways of telling us what it needs to survive. We have to train ourselves to listen to it. Plant trees, save water, use public transport! These are the very basic things that come to mind when it comes to working towards a greener environment. But is that enough? Can that actually lead to a solution? The effect can be almost mind blowing. According to this study from 2021, trees in greener spaces have the capability to cool an area by about 12 degrees! On the contrary, cities that do not have trees in their greener spaces, have a negligible effect on the cooling. Well, if a city in Colombia could do it, why not the rest of us? And Medellín in Colombia is living proof that regreening does help make the planet cooler. What did the Colombian city Medellín do to achieve a two degrees cooler climate? Medellín, like other major growing cities in the world, had been focusing on construction and development. It used to be known as the ‘City of Eternal Spring’ because of its temperate climate, but the heat has gradually gone up in the last few years. In 2016, Mayor Federico Gutiérrez began to take measures to build a ‘Green Corridor’. He invested $16.3 million to plant over 2.5 million plants and 880,000 trees in the city. This has now led to an ultimate drop in temperature levels, and now the city boasts being 2 degrees cooler than before. Isn’t that wonderful! Read more on how the city is handling the urban heat by planting trees.
Medellín, the city with a population of 2.5 million; Photo by David Gabrić
Medellín, the city with a population of 2.5 million; Photo by David Gabrić

Impact of lower temperature on humans Aside from the fact that maintaining a cooler atmosphere will mean that the planet, and its inhabitants will not have to face unbearable living conditions due to scorching heat, lowering the temperature levels does have very good impacts on us: Longer lifespan: A rise in temperature levels gives rise to a lot of health problems including heat strokes, blood pressure issues and what not. Keeping the planet cool leads to a healthy atmosphere for the earthlings to survive. Cleaner air: The accumulated dust and pollution trapped in the atmosphere gives rise to carbon dioxide and methane levels in the air. So if we work towards reducing the CO2 levels by resorting to measures like reforestation, it will both suck down carbon and lead to cleaner air. You will be surprised to know how important clean air is for our mental health and our lifespan in general. Instead of inhaling carcinogenic, polluted air, we will be inhaling clean air that does wonders to our mind and soul, not to forget, the body. Better moods: Studies have shown that rising temperature levels lead to a bad mood and higher crime rates in cities. Check out this article to learn more about this. It is sad how we need to be convinced of the fact that a better environment is actually good for us. As if we have a choice. So how do we achieve this? On an individual level, it is easier said than done to plant trees on a large scale that will be enough to bring down temperatures. But greening our city roads isn't the only measure we can take to mitigate the effects of the climate crisis. We can also green our rooftops. A scientific report published in Nature in February concludes that the potential of green roofs to mitigate urban heat and related energy consumption is a highly underrated nature-based climate solution. The idea is to plan the urban infrastructure in such a way that irrigation is possible on rooftops, thereby attracting rains. The soil on the roof will absorb the coolness of the water, thereby making the building, and the area surrounding it, cooler.
Arial view of a building with trees on its rooftop: Photo by CHUTTERSNAP
Arial view of a building with trees on its rooftop: Photo by CHUTTERSNAP

Basel, a city in Switzerland, was the first city to mandate green spaces on the rooftops of new buildings. The government believes that we are gradually losing access to greener spaces due to the growing urban spaces. If that is the case, then why not use the unutilized rooftops on buildings to build a green pasture that is good for the people and the environment? Learn more about this here. So what is this green roof system? It is an extended version of your roof with added waterproofing, better drainage, root repellants, etc. so the roof becomes more conducive to irrigation. This article gives us a lot more insight into the green roof system. A higher temperature is neither good for us, nor the environment. A lot of companies like Bauder Flat Roofs, Sempergreen Group, Onduline Group are offering high-quality and waterproof green roofs to help mitigate the impact of the heat island effect. See what Brice Sendra, CEO of Demet'Air has to say about offering green roof solutions:
https://youtu.be/cVVDjjDipB0


Everyone is investing towards construction, development and urban infrastructure. Even Medellín was doing it. At one point, they realized their priorities towards the planet and for the future. If the Colombian city of Medellin can achieve it, so can the rest of the world. Nothing is impossible. According to Bill Gates, the way the urban infrastructure scene is growing, the world will build an entire New York City every month for the next 40 years. We cannot stop development, but we have to find a way to do it without affecting climate change. To combat the climate crisis, we need to start thinking very differently when constructing these urban areas. We just need to get out of the Ostrich mentality and face the truth. That itself is one big step towards change. It is heartening to see that some cities are realizing this and working towards change. The rest of us, however, are not doing things fast enough. We can no longer ignore reality. The need to change, and work towards cooling our Earth, should begin soon. Learn more about how green roofs can be used to reduce heat islands:

  • johnte ndeto

    4 d

    These natural elements provide shade, absorb carbon dioxide, and release oxygen, helping to mitigate the urban heat island effect and reduce temperatures in cities.

    1
    • Annett Michuki..

      4 d

      quite an inspiring piece

      1
      • johnte ndeto

        4 d

        @annett_michuki By increasing green spaces in cities, we can enhance carbon sequestration and mitigate the effects of climate change by reducing greenhouse gas concentrations.

        1
      • mary Mwihaki

        3 w

        This is so encouraging we need more solution and desire to bring change in climate

        4
        • johnte ndeto

          4 d

          @mary_dosarah Vegetation acts as natural air filters, trapping pollutants and particulate matter from the air.

          1
        • Gorffly mokua

          3 w

          While technology can play a crucial role in promoting sustainability, these solutions demonstrate that nature has valuable insights to offer in addressing climate change. 💚💚

          4
          • johnte ndeto

            4 d

            @gorffly_mokua through a process called evapotranspiration, plants release water vapor into the air as they photosynthesize and respire.

            1
          • George Kariuki

            3 w

            This is such an inspiring story about the power of nature. We need more green roofs and sustainable urban planning to combat climate change. Let's all do our part to make a difference.

            7
            • johnte ndeto

              4 d

              @george_kariuki Incorporating green spaces into urban environments supports biodiversity by providing habitat for various plant and animal species.

              1
            • Jane Wangui

              3 w

              We only need to make a choice to change the climate.. everything we need and can do we already know..the only thing that is lacking is the desire to bring change.

              7
              • johnte ndeto

                4 d

                @jane_wangui green spaces offer additional ecosystem services, such as flood mitigation, soil stabilization, and recreational opportunities for residents.

                1
              • winnie nguru

                3 w

                Maybe sometimes all we need to do is go back to the basics and start again

                9
                • johnte ndeto

                  4 d

                  @winnie_nguru it provides opportunities for recreation, relaxation, and social interaction.

                  1
                • walter lungayi

                  3 w

                  The example of Medellín's successful greening initiative highlights the potential for cities to combat climate change by prioritizing reforestation and sustainable urban development, offering valuable lessons for global environmental efforts.

                  13
                  • johnte ndeto

                    4 d

                    @walter_lungayi greenery has been linked to improved mental health, reduced stress levels, and increased physical activity.

                    1
                  • Rukia Ahmed Abdi

                    3 w

                    Wow😲this is so informative. Never knew that we have climate solutions in ancient times

                    15
                    • johnte ndeto

                      4 d

                      @rukia_ahmed_abdi This approach represents a harmonious blend of ancient wisdom and modern science in addressing the challenges of a changing climate.

                      1
                    Welcome, let's solve the climate crisis together
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