Climate change and extreme weather

Extreme weather appears to be happening more often, and getting more severe. But how much of it is down to climate change?

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Climate and weather are two different, but related, things. But what exactly is the difference? Put simply, weather is what you experience day to day: sun, rain, wind or snow. Look out of the window and you’ll see weather. Weather is unpredictable and there is a lot of local variation.  

Essentially, climate is the long term average of the weather for a specific region over a long period of time – typically 30 years or more. Climate change refers to long term changes to broad weather patterns that take place over several decades. This means it’s difficult to tie any single extreme weather event to climate change.

Scientists looking at these trends are now finding that profound changes may be happening over much shorter timescales. These changes are what’s making extreme weather more likely and more severe.

The effects of climate change on UK weather

The UK has what scientists call a ‘temperate-maritime’ climate. The British Isles generally experience warm summers and cool winters, and only rarely do we face the extremes of heat or cold common in other climates.

There is increasing evidence that things are changing. Heatwaves, storms and flooding, wildfires and even extremely cold snaps are becoming more common.

For the UK, heatwaves are considered extreme beyond the 30ºC mark. A record high temperature of 38.7ºC was recorded in Cambridge on 25 July 2019, with many more similarly high temperatures recorded countrywide. This broke a previous record of 38.5ºC in Kent in August 2003. And the longest stretch of extreme heatwave temperatures was recorded in August 2020.

Flood risk will go up, because it’ll rain less often, but more heavily. This is partly because generally speaking, warmer air can hold more moisture – and that means more intense rainfall. 

The UN Intergovernmental Panel on Climate Change believes that the UK will receive about 10 percent more rainfall on average per year by 2100 compared to 1986–2005. 

While scientists are often reluctant to put single extreme weather events down to climate change, it’s become more and more clear that new patterns – of severity, frequency and impact of extreme weather events – are emerging. 

Wildfires, storms and floods around the world

These changes are happening not just locally and regionally, but also globally. Weather conditions seem to be changing markedly from the long term average, with extremes of heat, cold, drought, or increased rainfall dominating the weather with greater frequency.

Many scientists believe that all the weather the world is now experiencing (so not just the extreme weather) is affected in some way or another by the climate emergency, caused primarily by emissions of CO2 from fossil fuels and by other greenhouse gases. 

This now seems to include more and more extreme weather events. Increasing temperatures are leading to heatwaves and drought in many parts of the world – and devastating fires in Australia, the Amazon and California just in the past year. Storms and floods appear to be becoming more intense. More and more, such events are being linked convincingly with climate change. 

Extreme weather is not just more frequent, but more severe 

Experts are now able to confirm that, for example, storm surges are likely to be more severe because sea levels are rising, and storms are getting demonstrably stronger in terms of their wind speed.

Scientists have been warning humanity for decades now that climate change would change our weather systems.

Extreme weather can have extreme impacts on human settlements. Fires, floods, droughts, storms, and other natural disasters, are being linked to rising global temperatures. Fires have razed large swathes of Australia, the Amazon and the US – which also suffered unprecedented flooding in 2019.

Now that the climate emergency is becoming more starkly apparent – in the form of floodwaters and superstorms, and millions of people displaced and their homes and livelihoods destroyed – the rescue mission for the climate emergency must start in earnest.