In 2016 atmospheric carbon dioxide levels rose above 400 parts per million, contrasting with the pre-industrial level of 280ppm.

In 100 years, ocean acidity levels have risen significantly — as atmospheric carbon dioxide increased by 30 per cent over pre-industrial levels.

Over the past 800,000 years, ice core data shows that carbon dioxide has varied from values as low as 180 parts per million (ppm) to the pre-industrial level of 270ppm.

I think it's disingenuous to pretend that we can continue to enjoy a lifestyle sustained by 20th-century standards of transportation, yet somehow magically revert to pre-industrial levels of carbon emission.

From pre-industrial levels of about 280 parts per million (ppm) it has this year averaged 401ppm — the first time it has consistently breached the 400ppm benchmark.