Why North America's killer heat scares me

We've just enjoyed our first blissful slot sleepover weekend with our 20-month granddaughter, Hazel, so maybe that softened me up.

Or perhaps it was a week's leave away from the news that rusted my BBC armour of emotional detachment from the climate story.

Either way, I confess to a gut-tightening sense of foreboding when Hazel left and I caught up with North America's killer heat dome on TV.

That's not because new record temperatures were set in the north-western US and Canada - that happens from time to time. No, it's because old records were smashed so dramatically.

The previous all-time Canada record of 45C was set in the 1937 Dust Bowl era when, like this year, the parched ground failed to mitigate temperatures.

Normally records like this are over-topped by a fraction of a degree, but this year the former high was obliterated on three days running.

The final temperature in the town of Lytton was fully 4.6C higher than the old record. Emissions from human activities inarguably contributed to the rise, increasing global average temperature by about 1.2C since the late 1800s.

A study by an international team of researchers this week concluded the heatwave that scorched western Canada and US was "virtually impossible" without climate change.

The team, which is part of the World Weather Attribution network, described it as a one-in-a-1,000-year event which would have been 150 times less likely without human influence on the climate.