Various theories have been suggested to explain this ‘extra’ warmth, such as an apparent reduction in the low-level cloud cover that tends to cool the planet, and prolonged ocean heat following the end of El Niño.
“The question is whether this acceleration is something persistent linked to human activities that means we will have steeper warming in the future, or whether it is a part of natural variability,” Dr Gößling adds.
“At the moment it’s very hard to say.”
Despite this uncertainty, scientists stress that humans still have control over the future climate, and sharp reductions in emissions can lessen the consequences of warming.
“Even if 1.5 degrees is out the window, we still can probably limit warming to 1.6C, 1.7C or 1.8C this century,” says Dr Hausfather.
“That’s going to be far, far better than if we keep burning coal, oil and gas unabated and end up at 3C or 4C – it still really matters.”
