Many people are by now familiar with the Keeling curve, a graph showing the steady increase in carbon dioxide in the atmosphere measured over decades by the Mauna Loa Observatory, the world’s longest-running CO2 monitoring station.
The research, started by renowned climate scientist Dave Keeling in 1958, is considered one of the pillars of the scientific consensus that human activity is the main driver of climate change. This year, the data revealed a troubling milestone: CO2 concentrations had passed 400 parts per million for the first time since the dawn of human civilization.
Less familiar, but every bit as troubling to climate scientists, is a parallel slope on a different track of climate data: the increase of CO2 in the world’s oceans, which has been climbing almost in lockstep with the Keeling curve. The rising carbon level is cranking up ocean acidity with astonishing speed—probably 10 times faster than at any point in about 50 million years, according to scientists.
Among other concerns, scientists are now increasingly worried that the acidification of the oceans is likely to cause one of the first abrupt, severe and probably irreversible consequences of global climate change: the loss of tropical coral reefs.