Why is it flooding everywhere?

Summer. A season of sun, respite and ice cream… or so you’d think. An increase in flash floods across the globe has turned expected months of warmth and sunshine into an unpredictable hell in places like the UK, Germany, Belgium, India and China. And just last week, New York was flooded after an unprecedented amount of rainfall (more than three inches of rain fell in one hour, shattering all previous records) poured on the city as Storm Ida swept across America, causing cars to be fully submerged in water and people drowning in their basements. At the time of writing, we know that 45 people died in the floods.

Why is this suddenly happening all over the world? Should we expect all of our summers to be filled with floods from now on?

In short, climate change is responsible for the increase in precipitation and extreme weather events. Scientists have recently concluded that the record rainfall that led to the July floods in Germany, including a 24-hour total of 3.5 inches in the Ahr and Erft river, was a once in a 400-year event. However, the report also found that the climate crisis has made extreme rainfall between 1.2 and nine times more likely and that the downpours in the region are now three to 19 per cent more intense than before.

Yet whether you should expect more summer floods depends on where you’re based, as some places will experience less precipitation and more droughts with warming temperatures. The 2021 IPCC report confirms this, stating that ​“precipitation is projected to increase over high latitudes, the equatorial Pacific and parts of the monsoon regions, but decrease over parts of the subtropics and in limited areas of the tropics.”

Meanwhile, data from the Met Office shows that extended periods of extreme rainfall are now seven times more likely in the UK. So yes, this level of summer flooding is just the beginning and, unless we learn to adapt and tackle climate change, it’s going to get a hell of a lot worse.

There’s a reason why, specifically, summer rainfall can cause dramatic flash floods around the world. Although cold weather causes long-lasting bouts of heavy rain which can also cause flooding, heavy rainfall in the summer often follows heatwaves, as extended periods of hot weather allow the air to hold more moisture. Hot weather also causes the ground to dry up and become hard, making it harder to absorb water quickly. Flash flooding in the summer happens when rain falls so fast that the ground can’t absorb it quickly enough, leading to excess surface water. Cities suffer particularly badly because outdated or clogged drainage systems can’t cope and there isn’t enough earth on the ground to absorb the water. The water ends up pooling on concrete until it is drained.

Increasing floods are a problem. Not only are they a huge economic issue, causing around £300 million of damage to property every year in the UK, floodwater can also contaminate, spread disease and cause health problems. And that’s not even thinking about the mental trauma of the loss of life, homes, possessions and businesses.

What can be done? A lot, actually. Aside from trying to slow climate change in general, there are practical changes that can be made to absorb the devastating impact of future floods.

In the Netherlands, disastrous floods have been avoided after officials ordered the creation of natural floodplains, where water has been diverted into a 1,300-acre floodplain created to duplicate the river’s old overflow channels. Other countries could certainly follow suit by giving more space to the natural flows of major rivers and seeking other nature-centred solutions.

Drainage and water supply systems also need to be maintained and improved, as well as energy supply and transport infrastructure, both of which are immediately affected during floods. We need to plant more gardens, hedges and trees to catch rainfall, increase water absorption and slow surface water runoff. Currently, the more concrete we pour into our cities to create new roads and car parks, the less soil can absorb the water.

Sustainability also has to be at the forefront of urban planning and flood risk has to be taken into account in order to include better drainage systems. Some great solutions include permeable paving, green roofs and swales shallow vegetated channels on roads designed to store run off.

On top of that, governments must make sure that people are educated and prepared for flooding events. Everyone should be taught how to create ​“flood kits”, which include items needed in the event of evacuation, sandbags should be provided for those whose homes are at risk and advice on home insurance should be made accessible.

It’s time to prepare for Wet Girl Summer in years to come and swap your sandals for wellies. You haven’t seen anything yet.