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. Climatologists are nervous of being accused of alarmism - but many have been frankly alarmed for some time now. "The extreme nature of the record, along with others, is a cause for real concern," says veteran scientist Professor Sir Brian Hoskins. "What the climate models project for the future is what we would get if we are lucky. The models' behaviour may be too conservative."