Expert Opinion: Extreme heat warning for the UK and climate change

Professor Ric Williams is Chair in Ocean and Climate Science and co-lead of the University’s Climate Futures research theme:

The UK Met Office for the first time ever has issued a red extreme heat warning for parts of England. All the country has an amber extreme heat warming, but central and southern England have a red extreme heat warning and are braced for high temperatures approaching the high 30s C or even 40oC on Monday and Tuesday. The Chief Executive of the Met Office, Dr Penny Endersby, said the warning was unprecedented.  There is a 80% chance that the previous UK temperature record of 38.7oC in Cambridge in July 2019 will be exceeded and even a 50% possibility of 40oC being reached.  Network Rail and Transport for London have issued advice encouraging customers not to travel on Monday 18th and Tuesday 19th unless your travel is essential.

What will happen with this heat wave?

The weather we experience depends on where the air comes from. This extreme heat for Monday and Tuesday is linked to the high temperatures experienced across France and Spain, leading to forest fires there. Usually we have westerly winds bringing mild and moist air from the Atlantic to the UK. Instead we have recently have had a high pressure system sitting over the UK and air temperatures have gradually increased. As that high pressure system moves eastward over the continent, the exceptionally warm air in southern France and Spain will be swept up to the UK, leading to the forecasts of extreme heat for Monday and Tuesday. Later in the week from Wednesday to Thursday, normality will return for the UK with cooler air coming in from the Atlantic and bands of heavy rainfall expected.

What is the connection with climate change?

It is always difficult to connect a weather event to climate change. We have often had these patterns of air flow and these patterns by themselves are not unusual. What is unusual is the extent of the warming. Weather model assessments of the last UK record heat wave that occurred in July 2019 revealed that the extent of this warming was 10 x more likely due to climate change. This analysis is likely to carry over to our present heat wave, so that these exceptional high temperatures are 10 x more likely due to climate change.

We have known for several decades that increasing the amount of carbon dioxide in the atmosphere leads to an increase in global-mean surface temperature. However, the last Intergovernmental Panel on Climate Change report released in 2021 concluded that human-caused emissions of greenhouse gases “have led to an increased frequency and/or intensity of some weather and climate extremes”, including droughts, extreme heat and record floods threatening the livelihoods for millions of people.   So what we are seeing over the UK for a few days is part of a bigger picture of climate extremes occurring across the globe.

What can we do?

We can mitigate against the personal effects of a heat wave by seeking the shade, carrying water and choosing our travel plans carefully. However, the bigger picture is what can we do about climate change? The only long-term solution is dealing with carbon emissions and reducing the amount of carbon we utilise. Some of the solution here is personal in terms of our lifestyle choices in terms of what we eat, how we travel and how we heat or cool our homes and workplaces. A major part of the solution is institutional and how we collectively plan our futures via local and national governments, particularly in how energy is produced and utilised, and the level of support given to how we move to a low carbon future.

Professor Ric Williams is Chair in Ocean and Climate Science with the University’s School of Environmental Sciences and co-leads the Climate Futures research theme for the University of Liverpool,

Climate Futures Research theme

Responding to the global climate crisis through our research is the focus of the University’s Climate Futures Research theme. It brings together experts in a wide range of disciplines to explore impacts of climate change, develop solutions to environmental challenges and address knowledge gaps. Find out more by visiting this webpage.

Find out more about the University’s engagement in this Youtube video: Climate Futures: Developing Net Zero Solutions Using Research and Innovation – YouTube