WHETHER THE WEATHER BE GOOD: HOW DOES CLIMATE CHANGE AFFECT OUR WEATHER
We’ve been hearing for many years how our climate is changing and our weather is becoming more unpredictable. We are increasingly experiencing (and seeing) the impacts, particularly with this year’s hotter summer and the recent flooding in Pakistan.
We also know that in the UK for we will experience more frequent droughts, but wetter winters and more flash floods. However, we often don’t know how to explain this or why it is happening. Could we explain it to our children?
Our sustainability expert, Sarah Walkley, digs into climate change in more detail and how it affects our weather.
What’s happening to our climate?
Earth’s atmosphere is a protective bubble surrounding the planet, trapping in oxygen, water vapour and greenhouse gases like carbon dioxide and methane. Greenhouse gases are great at absorbing the sun’s heat which is reflected off the ground. Without them, the Earth would be a much, much colder – more like Mars and be impossible for life as we know it to exist.
However, by chopping down trees, burning fossil fuels to make electricity or driving our cars, we’re making more of those greenhouse gases than the earth can absorb. It’s a bit like leaving the bath tap running with the plug in; eventually the bath overflows. But unlike the bath water, which pours over the top, there is nowhere for the greenhouse gases to go. They just stay in our atmosphere doing what they do best – absorbing heat. The result is our beautiful planet getting warmer and warmer.
If the weather is getting warmer, then why are we getting more rain?
It's perhaps easy to understand how that leads to hotter summers and heatwaves. But how does a warmer planet result in temperate climates like the UK getting wetter? Surely, that just leads to drought? Yes, in equatorial countries (those that are closer to the equator) or when the UK experiences a heatwave like the one we have had this summer. However, that extra heat also supercharges other processes.
The heat of the sun causes water from rivers, lakes and oceans to evaporate, filling the air with lots of tiny droplets that eventually come together to form rain clouds. The hotter it is, the more water is evaporated, resulting in bigger, heavier clouds. These burst suddenly, causing storms and heavier downpours.
If they come on the back of a prolonged period of dry weather, then we experience flash floods.
You would imagine that the ground is like a sponge; when it is dry, the sponge can absorb a lot of water, but it can only absorb so much. However, wet grass can absorb much more water than dry grass. There is a great video from Dr Rob Thompson at the University of Reading which shows the difference between wet and dry grass.
So what can we do?
If the ground is too dry the water doesn’t sink in; it just runs off the top and causes flooding. The problem is worse still in cities, as roads, pavements and concrete driveways mean there is less bare ground and fewer places for the water to soak away. Maintaining as much garden as you have space for provides somewhere for the water to go, as well as being a haven for us and for wildlife.
Sarah Walkley is a freelance writer and researcher on a mission to empower everyone to play their part in addressing climate change and nature loss.
She set up Purplefully to help organisations develop their sustainability strategy and communication.
