Fires, floods, heatwaves, and droughts. The deadly weather that has unfolded in recent weeks has left climate scientists “shocked” and concerned that extreme events are arriving even faster than models predicted.

In southern Oregon, a fire over an area 25 times the size of Manhattan has raged for weeks, aided by a record-shattering heat wave. In China, floods left 51 dead after a year’s worth of rain fell in a single day in the central city of Zhengzhou causing more than $10bn in damages.

And in Russia, a state of emergency has been declared in Yakutia in the Far East, where authorities are creating artificial rain by seeding clouds with silver iodide in an attempt to put out more than 200 fires.

Climate scientists say the severity of these events is simply “off-scale” compared with what atmospheric models forecast — even when global warming is fully taken into account.

“I think I would be speaking for many climate scientists to say that we are a bit shocked at what we are seeing,” said Chris Rapley, professor of climate science at University College London. “There is a dramatic change in the frequency with which extreme [weather] events occur.”

From the deadlyflooding in Germany last week, to scorching heat in Canada, and a deluge in the Black Sea region, the pace and scale of catastrophic damage has been almost unimaginable, even for experts who have spent their lives studying it.

One driver behind many of these events is the shifting pattern of the jet stream, a fast-flowing band of air that governs weather in the Northern hemisphere. It is becoming slower and wavier, particularly in summer months.