Europe is approaching levels at which some oil refineries should start producing fewer, according to a Bloomberg report. Greece is fighting fires and the country’s capital could see temperatures above 40C (104F) in the following weeks. In Poland, heat can soon exceed the point where the country’s leading fuel supplier can operate its refineries properly. Macquarie Group estimates that heat-related disturbances in European factories reached about 1 million barrels a day last year – almost 10% of what they usually manage. Temperatures in Europe are much higher than seasonal ones and there is no indication that this will change soon. Looking further away in the future, Sweden’s largest refinery says climate change makes fuel production difficult. “European refineries were designed in the 1960s and ’70s,” said Alan Gelder, vice president of refining, chemical and oil markets of consultants Wood Mackenzie Ltd. “The world has become warmer since”.