Atop the Acropolis ancient hill, tourists visit the Parthenon temple during a heat wave on July 20, 2023 in Athens, Greece. The Acropolis of Athens and other archaeological sites in Greece announced reduced opening hours due to the heatwave conditions.Milos Bicanski | Getty Images News | Getty ImagesEurope is set for another heatwave in the coming days, pushing temperatures back toward record levels as an oppressive “heat dome” expands over the southern half of the continent.It comes shortly after the planet registered its hottest day since records began for the third time in just four days earlier this month. The U.S. and China also saw temperatures climb above 50 degrees Celsius (122 Fahrenheit) in recent days.The scorching heat hitting hundreds of millions of people across the globe is fueled by the climate emergency. Scientists say the recent spate of heat records reaffirms the increasing urgency to slash greenhouse gas emissions as quickly and as deeply as possible.An intense and prolonged series of heatwaves has brought temperatures in parts of Greece, eastern Spain and Sardinia and Sicily in southern Italy to over 45 degrees Celsius in recent days.The European Centre for Medium-Range Weather Forecasts (ECMWF) said on its website that Europe is experiencing some of the hottest temperatures of the summer so far, as a growing “heat dome” allows a warm air mass to build up.A heat dome occurs when a high-pressure circulation in the atmosphere acts likes a lid or a cap, trapping hot air in place and creating vast areas of sweltering heat.Tourists use umbrellas to protect themselves from the sun at Colosseo area (Colosseum), during the ongoing heat wave in Rome, Italy. Many places in Italy have seen successive days over 40C.Stefano Montesi – Corbis | Getty Images News | Getty ImagesResearchers at ECMWF on Wednesday said that a “slightly less warm air mass from the north” from Thursday was set to provide some respite. “However, this relief may be short lived, as another period of extreme heat is forecast for the end of this week and the beginning of next week.”Meteorologists in Italy said Friday that temperatures in the center and south of the country are expected to record peaks close to 40 degrees Celsius in the coming days, before a hot air mass returns at the beginning of next week — pushing the mercury close to record-breaking levels yet again.Temperatures in the Italian islands of Sardinia and Sicily have crept toward the European record in recent days.The hottest temperature reportedly ever logged in Europe was 48.8 degrees Celsius near the ancient city of Syracuse on the coast of Sicily in August 2021.Italian weather news service Meteo.it said that next week’s heatwave could drive temperatures to peak at 47 degrees Celsius in the south and on the Mediterranean islands of Sardinia and Sicily.The Italian government on Wednesday issued extreme heat red alerts for 23 cities, as temperatures sizzled nationwide. It meant that only four of the country’s major cities were not on red alert — which is issued when heat is so intense that the health ministry considers it a risk to the whole population.’Absolute vigilance’In Greece, wildfires have gradually subsided after water bombers and reinforcements sent by Italy, France and Israel helped emergency workers to battle blazes that had razed swathes of forest this week.Temperatures nationwide have risen, however, with the mercury expected to hit 45 degrees Celsius in the coming days.Greek Prime Minister Kyriakos Mitsotakis warned on Thursday that “the hard times are clearly not over yet,” in remarks quoted by Sky News. “We are facing another heat wave and a possible strengthening of the winds … absolute vigilance and absolute readiness are required over the next few days,” he added.Greece’s Culture Ministry said Thursday that all archaeological sites and monuments, including the Acropolis, would close each afternoon through to Sunday.A woman walks with an umbrella at Plaza Mayor during the elections campaign as Spain faces another heatwave on July 19, 2023 in Madrid, Spain.Pablo Blazquez Dominguez | Getty Images News | Getty ImagesIn Spain, the state weather agency AEMET said extreme heat will likely abate in most of the country during the last week of July, with temperatures falling to below-average levels.It comes after a flurry of temperature records nationwide on Thursday, with Malaga airport experiencing its warmest night since records began over 70 years ago.Temperatures at the airport did not drop below 31.6 degrees Celsius overnight, AEMET said, noting that this surpassed the previous record by more than 2 degrees Celsius.