This year the climate is passing a gloomy threshold. The concentration of carbon-dioxide in the atmosphere is reaching 417 parts per million: an increase of 50 per cent since humans embarked on the industrial revolution and began to emit greenhouse gasses at large scales.
Measurements at the Mauna Loa observatory in Hawaii are revealing that CO₂ concentrations have already been above this level on some days, and are expected to remain above this symbolic threshold for around three months.
Next year, CO₂ concentrations are expected be more than 50% above pre-industrial across most of the year, and will continue to rise until global emissions reach net zero.
Prof Richard Betts MBE is Head of Climate Impacts Research at the Met Office, and one of his areas of research is forecasting the rise in atmospheric carbon dioxide. Prof Betts said: “Humans began burning fossil fuels at large scales at the end of the Eighteenth Century, and it took about 200 years for the atmosphere to see a 25 per cent increase in the atmospheric concentration of carbon dioxide, but only another 35 years to reach this year’s sorry milestone of a 50 per cent increase.”
You can read more about CO₂ passing this symbolic threshold in Prof Betts’s article in Carbon Brief.