As more and more greenhouse gases are spewed into the atmosphere, it logically follows that the Earth is warming at a commensurate pace. Right? Not really. The pace of warming has in fact decreased since the 1980s, even as carbon emissions hit record highs. Skeptics like to point to this fact as proof that burning fossil fuels is not impacting the climate.
A new study published in Nature aims to make sense of the apparent contradiction. The report, authored by Shang-Ping Xie and colleagues at the Scripps Institution of Oceanography, attributes the "pause" in global warming to cooler temperatures in the Pacific Ocean due to a La Nina-like decadal cooling.
Xie says he can explain a lot of that simply by looking at what's been happening in the tropical waters of the Pacific Ocean. Waters there have been relatively cool, and that means the ocean can take up more heat than usual.
"It's gaining extra heat during the past 15 years, and that heat is being stored" in the deep ocean, he says.
There's no telling how long this cool phase will persist. But the previous Pacific cool phase, which started in the 1940s, lasted about 30 years. It can't last forever; the ocean will eventually return to a warm phase, "and when that happens, we will be seeing unprecedented rates of climate warming," he says.
Visit Climate Central for a thorough breakdown of the report, including how it fits with other contemporary climate research. The take away? While global warming is has indeed slowed, that is not a sign of things to come.
Photo: Guy Motil/Corbis