Global Warming On Hold

Here is an interesting piece on the current crisis, from Discovery News:

According to a new study in Geophysical Research Letters, global warming may have hit a speed bump and could go into hiding for decades.

Earth's climate continues to confound scientists. Following a 30-year trend of warming, global temperatures have flatlined since 2001 despite rising greenhouse gas concentrations, and a heat surplus that should have cranked up the planetary thermostat.

"This is nothing like anything we've seen since 1950," Kyle Swanson of the University of Wisconsin-Milwaukee said. "Cooling events since then had firm causes, like eruptions or large-magnitude La Ninas. This current cooling doesn't have one."

Instead, Swanson and colleague Anastasios Tsonis think a series of climate processes have aligned, conspiring to chill the climate. In 1997 and 1998, the tropical Pacific Ocean warmed rapidly in what Swanson called a "super El Nino event." It sent a shock wave through the oceans and atmosphere, jarring their circulation patterns into unison.

How does this square with temperature records from 2005-2007, by some measurements among the warmest years on record? When added up with the other four years since 2001, Swanson said the overall trend is flat, even though temperatures should have gone up by 0.2 degrees Centigrade (0.36 degrees Fahrenheit) during that time.

The discrepancy gets to the heart of one of the toughest problems in climate science -- identifying the difference between natural variability (like the occasional March snowstorm) from human-induced change.

But just what's causing the cooling is a mystery. Sinking water currents in the north Atlantic Ocean could be sucking heat down into the depths. Or an overabundance of tropical clouds may be reflecting more of the sun's energy than usual back out into space.

"It is possible that a fraction of the most recent rapid warming since the 1970s was due to a free variation in climate," Isaac Held of the National Oceanic and Atmospheric Administration in Princeton, New Jersey wrote in an email to Discovery News. "Suggesting that the warming might possibly slow down or even stagnate for a few years before rapid warming commences again."

Swanson thinks the trend could continue for up to 30 years. But he warned that it's just a hiccup, and that humans' penchant for spewing greenhouse gases will certainly come back to haunt us.

"When the climate kicks back out of this state, we'll have explosive warming," Swanson said. "Thirty years of greenhouse gas radiative forcing will still be there and then bang, the warming will return and be very aggressive."

Let’s review, shall we? 

1.       There has been no global warming for at least eight years, according to these climate scientists.  I gather that this is the consensus. 

2.      During that time, man-made greenhouse gases have been increasing.

3.      The climate models on which global warming predict an increase in temperature, contrary to what actually happened. 

4.      No one seems to have any idea why this cooling period is taking place. 

5.      It is possible that a fraction of the most recent rapid warming since the 1970s was due to a free variation in climate.”

6.      You can count on global warming kicking back in in about, oh, thirty years or so. 

Now that’s a lot to chew on.  Consider items 1-3: that’s what we used to call “falsification.”  It’s something every legitimate scientific theory or hypothesis must be subject to.  Of course one piece of contrary evidence doesn’t mean that the former is false, but it certainly does weaken it.  Number five is very significant because that period of pretty steep warming has always constituted the main empirical evidence for AGW.  But in spite of having no idea why the climate is behaving like it is, Dr. Swanson reassures us that “warming will return and be very aggressive.”  How he could possible know that is anyone’s guess. 

Surely thirty years of grace when it comes to global warming should be good news?  I predict that this study will completely uninteresting to the mainstream press.