Friday, February 27, 2015

New Research Results on Ocean Temperatures

The global temperature over the last 15 years or so has slowed down providing an opening for people denying global warming to post claims that the planet is not warming.  By going back to 1998, a record year due to an El Nino (and not to greenhouse gases) denialists have attempted to show that the global temperature is actually declining.  This attempt however is classic lying with statistics called "cherry picking".

Global temperatures have slowed though.  As I've discussed before this has to do with ocean temperatures.  In fact any discussion of global temperatures should be about the biosphere, i.e., both atmospheric and ocean temperatures.  In my earlier discussion, more heat was being absorbed by the ocean effectively slowing down the absorption in the atmosphere.  As described here, new results are now showing that:

Using temperature readings going back to the 1880s and IPCC climate models, the researchers determined that the timing of two large ocean cycles — the Pacific multidecadal oscillation and the Atlantic multidecadal oscillation — are responsible for the slow-down.

Scientific American’s Mark Fischetti explains:
The temperature of the Pacific and Atlantic oceans, particularly the upper layers, goes through natural cycles of warmer and cooler, driven by large circulations of water across these and the rest of the world’s seas. Warmer and cooler periods can last several decades. The analysis shows that usually, when the northern Pacific is warming, the northern Atlantic is cooling, and vice versa –[ offsetting one another in their impact on atmospheric temperatures in the northern hemisphere. But the cycles, and their magnitude, don’t match exactly. For the past decade, the magnitude of northern Pacific cooling has been greater than that of northern Atlantic warming, resulting in a net slowdown in temperature rise, according to an email sent to me by Byron A. Steinman, assistant professor of earth and environmental sciences at the University of Minnesota in Duluth, who led the new study.
It is very important to understand that these phenomena aren't stopping or slowing down the greenhouse effects of CO2.  When the ocean effects subside, the effects on the atmosphere are going to rush back.  Instead of the slow advance we've experienced in the last ten years, we'll see a rapid change almost certainly generating far more extreme weather than what we are now seeing.