According to recent research We are now putting carbon into the atmosphere at a rate unprecedented since at least the age of the dinosaurs, scientists say.
The researchers have examined ocean sediments laid down during the so-called Palaeocene-Eocene Thermal Maximum – a dramatic warming event some 56 million years ago.
They find the amount of CO2 going into the air at its onset was four billion tonnes a year at most. Today’s figure is 10 times as big. The work is published in the journal Nature Geoscience.
The PETM has been extensively studied by scientists because it is regarded as a possible “analogue” for what is happening on Earth now.
But the team argues that the scale of human-produced carbon emissions means that the lessons we could learn from the ancient event may actually have limited relevance. “We have effectively entered an era of a no-analogue state, which represents a fundamental challenge to constraining future climate projections,” they write in their paper.