Everyone knows that shade from green plants is exactly what everyone is looking for in the city in the summer heat. Recently, the fact that plantations do help reduce urban temperatures has been confirmed through satellite studies.
Green zones and cities
A study was recently published in Nature Communications on how the presence of green zones in cities helps to cool them down. The fact that this effect exists at all is beyond doubt, because it is recorded not only by research, but also by people’s own experience.
Why urban areas heat up more than nearby rural areas is also understandable. This is the so-called heat island effect: lots of cars, people and dark surfaces working together as an energy accumulator.
So what is the purpose of the new study, involving Landsat 8, which is jointly led by NASA and the U.S. Geological Survey? Researchers decided to test whether the impact of green space on major cities in the Global South was different compared to the Global North.
South and North
In general, the terms “Global South” and “Global North” are rather conventional. The authors of the study used them to distinguish large cities in predominantly developed countries from those in poorer places.
In either case, the average land surface temperature for the hottest month of 2018 for each of them was calculated for each city, as well as the average of the hottest months from 2017 through 2019. And already based on these figures they calculated how much green spaces influenced the temperature.
Studies have shown that in cities in the Global South, they produce only 70% of the effectiveness they show in developed countries. Satellite data show that in the first ones they reduce the average temperature by 2.5°C, while in the second ones they reduce the average temperature by 3.6°C
As the authors of the study note, there are many reasons for this. On the one hand, cities in the south are on average closer to the equator than in the north. On the other hand, there’s simply much less green space per square kilometer of urban development on average. This means that any heat waves hit them harder.
Meanwhile, there is a significant difference in green efficiency between different cities in the south. Scientists believe that we need to understand what causes this particular difference and, based on these findings, form a solution for less developed countries on how they can keep away from the heat.
Provided by phys.org
