One of the consequences of climate change is an increase in the intensity and frequency of extreme weather events. And heatwaves are extreme weather events, as are droughts, excessive precipitation, hurricanes and storms. Research clearly shows that climate change is definitely making these events more frequent and intense. The World Weather Attribution initiative has been conducting analyses of extreme weather occurrences and it has found that the highest annual daily average temperatures were warmer across the globe than a century ago.
According to the UK Met Office “summer 2018 was the equal-second warmest summer in a UK series from 1884 for mean maximum temperature (shared with 1995) with summer 1976 hottest”. A study by the Met Office showed that “likelihood of the UK experiencing a summer as hot or hotter than 2018 is a little over 1 in 10. It is 30 times more likely to occur now than before the industrial revolution because of the higher concentration of carbon dioxide (a greenhouse gas) in the atmosphere”.
Greenhouse gas (GHG) concentrations are increasing in the atmosphere and with them so are the frequency and intensity of heatwaves (in addition to other extreme weather events), which will be hotter and longer. Due to these GHG emissions, the average global temperatures have increased by 1C since pre-industrial times (1850-1900) and in the UK, temperatures have risen by a similar number.