The European Commission Joint Research Centre (EC-JRC) has warned that the current drought could be the worst in 500 years.
And it has predicted that severe drought will worsen in Europe, potentially reaching 47% of the continent.
The predictions were announced by senior researcher Andrea Toreti in an online news conference on Tuesday afternoon.
"We haven't analysed fully the event (this year's drought), because it is still ongoing, but based on my experience I think that this is perhaps even more extreme than 2018," he said.
"Just to give you an idea the 2018 drought was so extreme that, looking back at least the last 500 years, there were no other events similar to the drought of 2018, but this year I think it is really worse than 2018."
According to Toreti, what is causing concern is that "looking at the next three months, we see still a very high risk of dry conditions over western and central Europe, as well as the UK."
Toreti said that the areas affected by drought and lack of water will increase and that if effective mitigation measures are not taken "this intensity and frequency will increase dramatically over Europe, both in the north and in the south."
Italy -- in particular the River Po -- is among the most affected as well as southern France and large areas of Spain and Portugal.
"Our analysis indeed is pointing to extremely low flows affecting almost all the European rivers," said Toreti. "The Rhine river, for instance, that is causing big troubles for instance in the Netherlands."
France is in the midst of its fourth heat wave of the year: the government says soaring temperatures and lack of rain are causing its worst drought on record. Meteo France says the heat wave which began in the south is expected to spread across the country and last until the weekend.
Even in the UK, which is not known for its hot summers, a four-day extreme heat warning of more than 35 C has been issued once again for southern and central England, starting on Thursday evening. With some reservoirs recording low water levels, hosepipe bans are being extended across the country and Wales.