This is the Keeling Curve. It charts the concentration of carbon dioxide in the Earth’s atmosphere, based on measurements scientists have taken at the top of Mauna Loa, the world’s largest volcano, in Hawaii, every day since 1958.
It shows that the atmospheric CO2 level is accelerating upwards, despite the ever-more pressing need for it to fall, and that it has increased 15 per cent since the first Rio Earth summit in 1992, when leaders began talking about measures to control greenhouse gases.
The Keeling Curve is the best measure we have of growing emissions, which makes it an important tool in cutting them. Yet to most people, the graph will be unfamiliar. If asked, many would struggle to hazard a guess at the figure today: it’s currently around the 415 parts per million mark.
It need not be that way. During the coronavirus pandemic, people became accustomed to knowing, more or less, the daily rates of Covid cases and deaths in their country. That helped them understand, when cases rose, that action had to be taken to save lives.
That’s why Tortoise has decided – inspired by a conversation with Claire O’Neill at one of our ThinkIns – that the Keeling Curve’s measurement of atmospheric CO2 should be put on centre stage and have a spotlight swung towards it.
From now on, a Keeling Curve icon will be displayed on Tortoise’s Accelerating Net Zero page – signalling its ups and downs – just as a weather forecast might be tucked under the masthead of a traditional newspaper. The full graph will be updated regularly with the latest daily data from the Mauna Loa Observatory.