Counting On …

8th November 2021

Today’s agenda at COP26 features adaptation, loss and damage. The extreme weather conditions we have seen in recent years – droughts and wildfires, floods and heat waves, storms and cold snaps – are here to stay as a direct consequence of the 1C warming that has already taken place. Current efforts at COP26 will hopefully constrain further rises in temperature to no more than 1.5C.

Across the globe, communities are and will have to adapt to the changes that are happening in weather patterns. In the UK we need plan how we cope with more frequent and deeper floods, spasmodic heat waves and irregular growing seasons. In the Pacific region where there are many low lying islands and around river deltas such as in Bangladesh, there is the need to plan for rising sea levels  which not only submerged land where people live but also salinates water used for drinking and farming. Many sub Saharan regions are faced with prolonged heat waves that make daily life and farming near impossible. Whilst other regions will feel the affects of drought as rivers that are normally fed during the summer by the slow melt of glaciers, dry up as the glaciers disappear altogether. 

Time and again, the solution lies with trees, whether that is trees that interrupt, and delay the speed with which falling rain becomes flood water, trees that stabilise coasts vulnerable to erosion, tree shade that reduces experienced daytime temperatures, or trees that provide shade for crops and whose roots retain moisture in the soil. 

 “Locally, trees provide most of their cooling effect by shading. How warm we feel actually depends less on local air temperature, and more on how much electromagnetic radiation we emit to, and absorb from, our surroundings. A tree’s canopy acts like a parasol, blocking out up to 90% of the sun’s radiation, and increasing the amount of heat that we lose to our surroundings by cooling the ground beneath us.All up, the shade provided by trees can reduce our physiologically equivalent temperature (that is, how warm we feel our surroundings to be) by between seven and 15°C, depending on our latitude. So it’s no surprise that, in the height of summer, people throng to the delicious coolness of the shade provided by London parks, Parisian boulevards, and Mediterranean plazas.

Trees can also cool down buildings – especially when planted to the east or west – as their shade prevents solar radiation from penetrating windows, or heating up external walls. Experimental investigations and modelling studies in the USA have shown that shade from trees can reduce the air conditioning costs of detached houses by 20% to 30%.”

Author: Judith Russenberger

Environmentalist and theologian, with husband and three grown up children plus one cat, living in London SW14. I enjoy running and drinking coffee - ideally with a friend or a book.

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