Hot or Not? Making Sense of Climate Variability

To say that climate know-nothings like to pick and choose when it comes to interpreting the science is something of an understatement. "Prominent" - and I use the term loosely here - deniers like Dennis Avery, S. Fred Singer and Michael Asher have made a cottage industry of playing loose with the numbers and extrapolating short-term trends to make sweeping statements about global warming (see: one unusually cold month means global warming is over).

Which is why I have a feeling this study, entitled "Has the climate recently shifted?" (which will be published in an upcoming issue of the journal Geophysical Research Letters), will catch many a denier's eye. The main takeaway from this study is that there is a significant degree of variability in our climate system, and that, even though we may be entering a period of warming "stasis," long-term trends still point to significant warming due to anthropogenic forcing.

According to the authors, Kyle L. Swanson and Anastasios A. Tsonis of the University of Wisconsin-Milwaukee, the climate seems to have come to a point where two important modes of variability - the Northern Hemispheric atmospheric and oceanic modes, to be exact - have synchronized, or become coupled. This, they say, results in the climate system being "thrown into a new state," which will likely be marked by a flattening of the global average temperature trend.

How could a modal synchronization precipitate such a dramatic shift in the climate system? The reason, Swanson and Tsonis explain, is that the climate system becomes much more sensitive to the possibility of a shift when these important modes of variability align. When coupling between the two increases, the climate system is destabilized and a new and different state emerges - this is what climate scientists refer to as the "theory of synchronized chaos."

The authors provide a helpful analogy to illustrate how this theory works:

"Think of a bicycle team engaged in team time trial. The riders are all synchronized, with their motions carefully planned to maximize the teams' overall speed. However, if those riders were coupled together, for example by attaching their bikes together with a rope, the slightest misstep among one of the bikers would be communicated immediately through the team and would lead to a group crash."

Because such couplings have coincided with all the major climate shifts of the last century, they believe that the latest synchronization of the two modes, which occurred in 2001/02, indicates a temporary break in the consistent warming trend of the last three decades. (A multidecadal period of cooling had preceded the last coupling, which happened in 1976/77.)

They recognize, though, that the high degree of variability inherent to the climate system makes any prediction difficult and speculative, at best. Indeed, they attribute the recent period of cooling to an internal shift of climate processes, which they say remains poorly understood, and note that slight changes in how the oceans and atmosphere absorb and radiate heat could have influenced other short-term trends.

The high degree of uncertainty inherent to climate modeling itself makes this study, like the many that preceded it, thought-provoking but by no means conclusive - something the authors readily acknowledge in their conclusion: "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."

The rest of the section should be required reading for those who will undoubtedly use the authors' hypothesis to support their erroneous views. Here are a few key passages:

"Moreover, we caution that the shifts described here are presumably superimposed upon a long term warming trend due to anthropogenic forcing."

. . .

"Doing so is vital, as the future evolution of the global mean temperature may hold surprises on both the warm and cold ends of the spectrum due entirely to internal variability that lie well outside the envelope of a steady increasing global mean temperature."

This last passage is crucial:

"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. 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."

To deniers, who will ignore the authors' caveats, this study will seem like manna from heaven; to the rest of us, this will just serve as another reminder of how bad things could become.

Comments

[GH]

Last week, a "news" article in LA Times, summarizes the first of 40 state mandated studies.

Wow - GW is projected to cause ocean levels to rise up to 55 inches this century. Not even the IPCC is so nuts. Article used maps (of the LA coastline and basin, to indicate how my neighborhood will soon enough be under water. Imagine the cost of these studies to the poor State of CA - not to mention the cost of the tens, or more, of billions of $'s required to mitigate the impact.

As we all know, it is theorized - the sudden increase of CO2, since mid 20th Century that has caused this sudden rise of the oceans, and is blamed as the culprit for all that is projected to continue to accelerate as the earth warms further from the "anthropogenic forcing."

What rise is that? Along Los Angeles coastline - a funny thing has not happened. Nothing's changed.

http://co-ops.nos.noaa.gov/sltrends/sltrends_station.shtml?stnid=9410660

Data is charted from 1923-2006. A very clear consistent trend of rise. How much? Rate of 3 1/4 inches per century. Is there a change in the rate since 1923? Nope - just pulgging along.

They didn't tell us when suddenly in the future, the rate of increase is to change from 3 1/4 inches/100 years to 55 inches/91 years.

I went to bed understanding less about climate change, and more about why CA is $40 billion in debt.

[SFTor]

An excerpt:

"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."

Obviously, there are still unknowns in climate science. This does not jive with what I have heard so often: "the science is settled, the debate is over." It seems pretty inescapable that if we cannot answer the two propositions in the excerpt, we are not exactly dealing with settled science.

Lastly, how the authors purport to know what will happen after their suggested 30-year warming hiatus is another real mystery, as no one seems to have predicted this.

If we are going to

[Earl E]

I remember reading the word teraform in some science fiction book decades ago. It seemed fanciful, but the idea was that scientist would add things to the Martian atmosphere that would allow humans to eventually be able to breath.

Today, we realize we've been teraforming the Earth, unintentionally.

[geoffrobinson]

We need falsifiable predictions. Especially predictions which are counter-intuitive. Otherwise, I will continue to remain skeptical of global warming.

And if it doesn't make falsifiable predictions, it isn't science.

[SFTor]

AGW science has made falsifiable predictions. The specific prediction on the table is that "atmospheric CO2 concentration drive global temperatures, which will continue to rise with increasing atmospheric CO2 concentrat­ion."

That prediction has been falsified. Temperatures and CO2 have not risen together in the 20th and 21st centuries.

[BobLablah]

Please just show me the proof that our current climate is the ideal climate and I'll support you 100%.
PS: Obviously no one has any idea if it is better for the world to be 10 degrees colder or 10 degrees hotter. All I can tell you is no matter what you do both scenerios will eventually happen.

[Pharos]

Science can provide information, not proof You will have to make a decision for yourself based on incomplete knowledge. If that scares you, welcome to the real world. Science has done pretty well so far. You may choose to ignore parts that you don't like, that is your choice.

We have made remarkable progress in medicine, electronics and many other areas of technology based on science. It hardly seems credible that anyone could deny that science does produce results. Choosing to ignore only one area of science, that one area that simply provides answers one does not like, does not seem to me to be the act of a rational person.

[BobLablah]

Then please provide me with "information" that indicates our current climate is the ideal climate for our planet.

[SFTor]

10 degrees colder puts us in an Ice Age.
10 degrees hotter puts us back in the primordial soup.

We are talking about tighter margins than that.