For the past several years, a small group of scientists has warned that sometime early this century, the rate of global warming — which has remained largely steady for decades — might accelerate. Temperatures could rise higher, faster. The drumbeat of weather disasters may become more insistent.
And now, after what is poised to be the hottest year in recorded history, the same experts believe that it is already happening.
In a paper published last month, climate scientist James E. Hansen and a group of colleagues argued that the pace of global warming is poised to increase by 50 percent in the coming decades, with an accompanying escalation of impacts.
According to the scientists, an increased amount of heat energy trapped within the planet’s system — known as the planet’s “energy imbalance” — will accelerate warming. “If there’s more energy coming in than going out, you get warmer, and if you double that imbalance, you’re going to get warmer faster,” Hansen said in a phone interview.
Zeke Hausfather, a climate scientist with Berkeley Earth, has similarly called the last few months of temperatures “absolutely gobsmackingly bananas” and noted, “there is increasing evidence that global warming has accelerated over the past 15 years.”
But not everyone agrees. University of Pennsylvania climate scientist Michael Mann has argued that no acceleration is visible yet: “The truth is bad enough,” he wrote in a blog post. Many other researchers also remain skeptical, saying that while such an increase may be predicted in some climate simulations, they don’t see it clearly in the data from the planet itself. At least not yet. [Continue reading…]