Since last July, Earth’s average temperature has been at least 1.5 degrees Celsius (2.7 degrees Fahrenheit) above preindustrial levels.

As global temperatures spiked to their highest levels in recorded history on Monday, ambulances were screaming through the streets of Tokyo, carrying scores of people who had  collapsed amid an unrelenting heat wave. A monster typhoonwas emerging from the scorching waters of the Pacific Ocean, which were several degrees warmer than normal. Thousands of vacationers fled the idyllic mountain town of Jasper, Canada ahead of a fast-moving wall of wildfire flames.

By the end of the week — which saw the four hottest days ever observed by scientists — dozens had been killed in the raging floodwaters and massive mudslides triggered by Typhoon Gaemi. Half of Jasper was reduced to ash. And about 3.6 billion people around the planet had endured temperatures that would have been exceedingly rare in a world without burning fossil fuels and other human activities, according to an analysis by scientists at the group Climate Central.

These extraordinary global temperatures marked the culmination of an unprecedented global hot streak that has stunned even researchers who spent their whole careers studying climate change.