Climate change: US-Canada heatwave 'virtually impossible' without warming
The searing heat that scorched western Canada and the US at the end of June was "virtually impossible" without climate change, say scientists.
Scientists worry that global heating, largely as a result of burning fossil fuels, is now driving up temperatures faster than models predict.
Climate researchers have grown used to heatwaves breaking records all over the world in recent years. However, beating the previous national high temperature mark by more than 4C in one go, as happened in Canada last week, is virtually unprecedented.
Canada's previous national record for high temperature was 45C - but the recent heat in the village of Lytton in British Columbia saw a figure of 49.6C recorded at the height of the event.
All across the region, in the US states of Oregon and Washington and in the west of Canada, multiple cities hit new records far above 40C.
These temperatures had deadly consequences for hundreds of people, with spikes in sudden deaths and big increases in hospital visits for heat-related illness.
