Emergency services battled wildfires across swathes of southern Europe amid mass evacuations on Wednesday, as warnings sounded in London after Britain’s hottest day that the fight against climate change needed to be stepped up.

A blaze fuelled by gale force winds raged in mountains north of Athens, forcing hundreds including hospital patients to evacuate, and similar numbers fled in central Italy as gas tanks caught in a forest fire near the Tuscan town of Lucca exploded.

A brutal heat wave settled over southern Europe last week, part of a currently developing global pattern of rising temperatures — widely attributed by scientists and climatologists to human activity — that is forecast to dump searing heat on to much of China into late August.

It is also expected to trigger record power consumption in Central US states — thereby adding to the greenhouse gas emissions that nations across the world have pledged to cut — as homes and businesses crank up air conditioners to combat soaring temperatures predicted to last into next week.

While the record heat experienced last week around parts of the Mediterranean has eased, mercury readings have begun heading up again in Portugal and Spain and rising in Italy.

Portugal’s northern region’s Civil Protection commander Armando Silva said rising temperatures and strong winds would make it harder to fight the country’s largest wildfire, which has burned 10,000-12,000 hectares(38-46 square miles) since Sunday in and around the municipality of Murça.

In Spain, where emergency crews were tackling fire sin five regions, the national weather service AEMET also forecast higher temperatures.

Wildfires burned in several areas of Italy and 14 cities, including Rome, Milan and Florence, were due to be put on the country’s highest heat wave alert on Thursday, up from nine on Wednesday.

Forecasters there said that temperatures were expected to hit 40°C across a swathe of the north and centre this week.

That mark was topped in Britain for the first time on Tuesday, shattering the country’s previous temperature record by 1.6° Celsius.

The chief of science and technology of Britain’s Met Office, Stephen Belcher, said that unless greenhouse gas emissions were reduced, the country might experience similar heat waves every three years.