Why did Britain feel so hot in the 1920s?

Temperate maritime climate. Britain is an island country in western Europe, with a temperate maritime climate. In summer, the warm and humid temperature is between 15-30 degrees, and the number of air conditioners is only a few percent. With the development of human industrialization, the greenhouse effect caused by a large number of greenhouse gases and the change of atmospheric circulation have caused the abnormal temperature in summer in Britain. For Britain without extreme heat, more than 20 degrees is high temperature.