According to a new study, the slowdown in global warming over the last decade may be linked to a natural variation in the Pacific and Atlantic Ocean’s surface temperatures. However, the scientists have warned that the phenomenon is set to end soon so global warming will continue its course.
Researchers from the Penn State University have come up with a new study that states that the latest slowdown in manmade global warming over the past decade is a ‘false pause’ and is a direct result of the offsetting by cooling from natural cycles in the Pacific and Atlantic oceans – an effect that will reverse in coming decades and see increase in global temperatures.
The researchers have attributed the slowdown in climate warming to natural oscillations in the climate, which are internal to the climate system and which necessarily do not signal any slowdown in human-caused global warming.
Michael Mann, climatologist, geophysicist and a professor of Meteorology at Penn State University, and the lead author of the study, said, “Internal multidecadal variability in Northern Hemisphere temperatures likely offset anthropogenic warming over the past decade.”
In their study, the researchers distinguished between human-caused and natural climate variability in a bid to assess the impact of human-caused climate change on a variety of phenomena including drought and weather extremes. They also studied Pacific Decadal Oscillation (PDO) and the Atlantic Multidecadal Oscillation (AMO), which are the two key factors that play a significant role in global temperatures. The researchers stripped out ‘external forces’ on those oscillations including volcanoes and the burning of fossil fuels, which are known to have significant impact, in a bid to work out how much they varied naturally, or internally.
They found that the internal or natural variability plays a significant role and has a huge influence over the span of several decades on temperatures in the northern hemisphere. They estimated that the variability could have a 0.15 C warming or cooling effect and in recent years, it is having a cooling effect.
“Our findings do support the notion that the pause is likely to end. And perhaps 2014 does herald that at some level,” added Mann.