Peer-Reviewed Study Indicates Recent Warming Is Natural

Peer-Reviewed Study Indicates Recent Warming Is Natural
August 29, 2013

James M. Taylor

James M. Taylor is senior fellow for environment and energy policy at The Heartland Institute, and... (read full bio)

Nature is responsible for most of the planet’s warming in recent decades, a newly published peer-reviewed study indicates.

Writing in the journal Nature, scientists studied sea surface temperature variations in the eastern tropical Pacific Ocean, which is the region generating El Nino and La Nina events. The scientists found a close correlation between natural variations in the region’s surface water temperatures and ensuing global cooling and warming events. Importantly, a global climate model developed to reflect the regional sea surface temperatures replicated the lack of recent global warming despite continued increases in anthropogenic carbon dioxide emissions.

The scientists reported “the current [warming] hiatus is part of natural climate variability, tied specifically to a La-Nina-like decadal cooling.”

Even more importantly, the scientists’ climate model indicated these same natural forces account for most of the global warming during recent decades.

Climate scientist Judith Curry, who has generally been supportive of the United Nations Intergovernmental Panel on Climate Change narrative, explained the importance of the newly published study.

“My mind has been blown,” Curry wrote on her website.

“No matter what, I am coming up with natural internal variability associated accounting for significantly MORE than half of the observed warming,” Curry wrote after studying the model results. (Emphasis in the original).

“Like I said, my mind is blown,” Curry continued. “I have long argued that the pause was associated with the climate shift in the Pacific Ocean circulation, characterized by the change to the cool phase of the PDO.  I have further argued that if this is the case, then the warming since 1976 was heavily juiced by the warm phase of the PDO. I didn’t know how to quantify this, but I thought that it might account for at least half of the observed warming, and hence my questioning of the IPCC’s highly confident attribution of ‘most’ to AGW."

“Although this was not a specific conclusion of the paper (they focused on the period 2002-2012), the conclusion jumps out from their Fig 1 (and my eyeball analysis),” Curry noted.

Curry further explained her conclusion:

"If you accept the following two premises:

•    climate models are useful for untangling natural from anthropogenic climate variability/change
•    the missing heat is being sequestered in the deep ocean for the past decade or so

then an inescapable corollary seems to be:

•    the same natural internal variability (primarily PDO) that is responsible for the pause is a major and likely dominant cause (at least at the 50% level) of the warming in the last quarter of the 20th century.

Does this explanation rule out contributions to the pause from stratospheric aerosols, solar cooling, etc.?  No, but I am not seeing the potential from these forcing mechanisms to dominate over the PDO given the ‘fingerprint’ evidence."

James M. Taylor

James M. Taylor is senior fellow for environment and energy policy at The Heartland Institute, and... (read full bio)