UW-Milwaukee Study Could Realign Climate Change Theory.

The Iron Lady of Climate Research: Drop the Geek Language

By Bjarke Wiegand | March 16, 2009 | In: Science, Policy, Media

Climate researchers must stop speaking in code. There is a need to rethink climate communication so politicians can understand how urgent the need for action really is. So says Ann Henderson-Sellers, one of the climate struggle's veterans, in this interview with Monday Morning's Bjarke Wiegand.*

"I am fed up with academics who are scared of speaking out."

Ann Henderson-Sellers, professor of physical geography at Macquarie University, in Sydney, Australia, thinks global climate research has been infested by too much gobbledygook. According to her, rampant professional "code language" and fear of being misquoted by climate skeptics only serve to drag out the climate debate. In this interview with Monday Morning,* she calls for a transparent and honest debate as to what researchers can do in order to urge politicians to react more quickly to the climate threat.

"The need for action is beyond discussion. Reams of acknowledged scientific reports demonstrate that the climate changes are beyond question. The problem lies in the fact that this message seemingly has not been absorbed by politicians and the ordinary citizen. This is because, among other things, we as researchers have not been good enough at communicating and fear being misquoted."

Ann Henderson-Sellers is among the world's most knowledgeable climate researchers. In 2006 and 2007, she was Director of the U.N.'s http://www.wmo.int/pages/prog/wcp/index_en.html">World Climate Research Programme (WCRP), which monitors international research on the climate. For more than 35 years, she has advocated the need to act in face of the greenhouse effect. And it is quite evident that she herself does not belong to the category of scholars afraid of speaking out.

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Global Warming: On Hold?

Michael Reilly, Discovery News

March 2, 2009 -- For those who have endured this winter's frigid temperatures and today's heavy snowstorm in the Northeast, the concept of global warming may seem, well, almost wishful.

But climate is known to be variable -- a cold winter, or a few strung together doesn't mean the planet is cooling. Still, according to a new study in Geophysical Research Letters, global warming may have hit a speed bump and could go into hiding for decades.

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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.

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."

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Swanson and Tsonis observe that over the past century, the average global temperature has risen, but there have been periods when it has dropped temporarily. Swanson and Tsonis have been investigating how the natural climate variability may explain the shifts between these phases. This variability includes oscillations in the circulation of the ocean and the air. El Nino is the most famous of these oscillations, but there are others as well in the North Pacific and the North Atlantic. Only three times in the twentieth century did all these oscillations synchronize, after which the climate moved to a new state. This figure, from the paper, shows the periods of synchronization as cross-hatched bars.



Based on the study of chaotic systems, Swanson and Tsonis propose that the synchronization and climate shift are connected through cause and effect. Once a lot of oscillations are working in sync, even a small change to one of them can radiate out through the whole system and trigger a change. And along with the three shifts in the real climate, climate models also show a similar response when oscillations line up.

In their paper, Swanson and Tsonis then look at the past few years. They see a peak in synchronization in 2001 and 2002, and they also observe that in the years since, the temperature change has been on average flat (although much warmer than at the beginning of the century). They estimate that all the warming due to carbon dioxide should have driven the temperature up .25 degrees C since then. The fact that it hasn’t leads them to propose the the oceans and atmosphere have changed the way they handle heat. The oceans may have absorbed more heat due to a change in circulation, or the atmosphere may radiate more heat away by clouds. If this hypothesis is true, then it’s possible that the climate will remain in this new stage for some years to come before it shifts again.

Swanson and Tsonis write:

Of course, it is purely speculative to presume that the global mean temperature will remain near current levels for such an extended period of time. Moreover, we caution that the shifts described here are presumably superimposed upon a long term warming trend due to anthropogenic forcing.

They conclude with this warning:

Finally, it is vital to note that there is no comfort to be gained by having a climate with a significant degree of internal variability, even if it results in a near-term cessation of global warming. It is straightforward to argue that a climate with significant internal variability is a climate that is very sensitive to applied anthropogenic radiative anomalies (c.f. Roe (2009)). If the role of internal variability in the climate system is as large as this analysis would seem to suggest, warming over the 21st century may well be larger than that predicted by the current generation of models, given the propensity of those models to underestimate climate internal variability (Kravtsov and Spannagle 2008)

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4. Conclusions

The above observational and modeling results suggest the following intrinsic mechanism of the climate system leading to major climate shifts. First, the major climate modes tend to synchronize at some coupling strength. When this synchronous state is followed by an increase in the coupling strength, the network’s synchronous state is destroyed and after that climate emerges in a new state. The whole event marks a significant shift in climate. It is interesting to speculate on the climate shift after the 1970s event. The standard explanation for the post 1970s warming is that the radiative effect of greenhouse gases overcame shortwave reflection effects due to aerosols (Mann and Emanuel, 2006). However, comparison of the 2035 event in the 21st century simulation and the 1910s event in the observations with this event, suggests an alternative hypothesis, namely that the climate shifted after the 1970s event to a different state of a warmer climate, which may be superimposed on an anthropogenic warming trend.