The summer of 2018 was one of the hottest and driest on record in the UK, with temperatures reaching above 30ÂC for nine consecutive days and rainfall below average for most regions. Many people compared it to the legendary heatwave of 1976, which saw 18 days of temperatures above 30ÂC and a severe drought that lasted for more than a year. But how similar were these two extreme events, and what factors influenced them
According to the Met Office, both heatwaves were associated with a persistent high pressure system over the UK, which blocked the usual flow of cooler and wetter air from the Atlantic. This resulted in clear skies, strong sunshine and light winds, creating ideal conditions for heat to build up. However, there were some differences in the position and strength of the high pressure system, which affected the humidity and night-time temperatures. In 1976, the high pressure was centred further east, drawing up hot and humid air from the south. This made the nights more uncomfortable and increased the risk of thunderstorms. In 2018, the high pressure was centred more over Scandinavia, bringing in drier and less humid air from the north-east. This made the nights slightly cooler and reduced the chance of rain.
Another factor that influenced both heatwaves was the pattern of sea surface temperatures in the Atlantic Ocean. In both years, there was a contrast between cool water near Greenland, warm water further south and more cool water closer to the UK. This pattern has been linked to warmer and drier summers in the UK by affecting the jet stream and atmospheric circulation. However, this pattern is not a fixed feature and can change from year to year due to natural variability or human-induced climate change.
The most striking difference between the two heatwaves was the impact on water resources. In 1976, the UK had already experienced a long period of below-average rainfall since May 1975, leading to a severe drought that affected agriculture, wildlife and public health. The government introduced a Drought Act and appointed a Minister for Drought to encourage water conservation measures. Some of these measures included standpipes, hosepipe bans, water rationing and even sharing baths. In contrast, in 2018, the UK had a wet winter and spring before the heatwave, which replenished the groundwater and reservoir levels. Although some regions faced water shortages and restrictions, the situation was not as critical as in 1976.
In conclusion, both 2018 and 1976 were remarkable years for weather in the UK, with record-breaking heatwaves that challenged people's resilience and adaptation. However, they were not identical events, as they had different causes and consequences. Moreover, they occurred in different contexts of climate change, which may have influenced their frequency and intensity. As global temperatures continue to rise due to greenhouse gas emissions, heatwaves are expected to become more common and severe in the future, posing new challenges for society and the environment. aa16f39245