Extreme heat particularly affects the elderly and children, as well as people with heart, kidney and other diseases, by causing dehydration, heatstroke and worsening existing conditions, according to the WHO.
Most of the 200,000 deaths were "entirely preventable," says the organization's European director, Hans Kluge.
The consequences of climate change pose a clear and imminent threat, and its most immediate and deadly expression is extreme heat.
A heatwave hit large parts of Western Europe in late May. Spanish authorities said last week that this year had recorded the highest number of heat-related deaths for the month of May since 2015.
