Illustration only: not part of the paper
This paper has been out for a few days, and several people have alerted me to it. This new paper by Compo,G.P., and P.D. Sardeshmukh, 2008: Oceanic influences on recent continental warming. in the journal Climate Dynamics, is now in press. See the PDF here
This paper makes some significant claims regarding what is driving the observed climate changes. The emphasis is on the ocean as the main driving component, and the authors recognize that “a combination of natural and anthropogenic influences” may be at work. While they point to the oceans as a significant driver, they don’t offer much to explain what is driving the oceanic change.
Even so, this is a significant work, and I urge my visitors to read it, because it shows that GHG forcing is not the only occupant of the drivers seat. It also clearly illustrates the need to examine such cyclic ocean influences as the PDO and AMO more closely, and to consider them in projections of temperature.
Abstract:
“Evidence is presented that the recent worldwide land warming has occurred largely in response to a worldwide warming of the oceans rather than as a direct response to increasing greenhouse gases (GHGs) over land. Atmospheric model simulations of the last half-century with prescribed observed ocean temperature changes, but without prescribed GHG changes, account for most of the land warming. The oceanic influence has occurred through hydrodynamic-radiative teleconnections, primarily by moistening and warming the air over land and increasing the downward longwave radiation at the surface. The oceans may themselves have warmed from a combination of natural and anthropogenic influences.”
Conclusion:
“In summary, our results emphasize the significant role of remote oceanic influences, rather than the direct local effect of anthropogenic radiative forcings, in the recent continental warming. They suggest that the recent oceanic warming has caused the continents to warm through a different set of mechanisms than usually identified with the global impacts of SST changes. It has increased the humidity of the atmosphere, altered the atmospheric vertical motion and associated cloud fields, and perturbed the longwave and shortwave radiative fluxes at the continental surface. While continuous global measurements of most of these changes are not available through the 1961-2006 period, some humidity observations are available and do show upward trends over the continents. These include near-surface observations (Dai 2006) as well as satellite radiance measurements sensitive to upper tropospheric moisture (Soden et al. 2005).”
Although not a focus of this study, the degree to which the oceans themselves have recently warmed due to increased GHG, other anthropogenic, natural solar and volcanic forcings, or internal multi-decadal climate variations is a matter of active investigation (Stott et al. 2006; Knutson et al. 2006; Pierce et al. 2006). Reliable assessments of these contributing factors depend critically on reliable estimations of natural climate variability, either from the observational record or from coupled climate model simulations without anthropogenic forcings. Several recent studies suggest that the observed SST variability may be misrepresented in the coupled models used in preparing the IPCC’s Fourth Assessment Report, with substantial errors on interannual and decadal scales (e.g., Shukla et al. 2006, DelSole, 2006; Newman 2007; Newman et al. 2008). There is a hint of an underestimation of simulated decadal SST variability even in the published IPCC Report (Hegerl et al. 2007, FAQ9.2 Figure 1). Given these and other misrepresentations of natural oceanic variability on decadal scales (e.g., Zhang and McPhaden 2006), a role for natural causes of at least some of the recent oceanic warming should not be ruled out.
Regardless of whether or not the rapid recent oceanic warming has occurred largely from anthropogenic or natural influences, our study highlights its importance in accounting for the recent observed continental warming. Perhaps the most important conclusion to be drawn from our analysis is that the recent acceleration of global warming may not be occurring in quite the manner one might have imagined. The indirect and substantial role of the oceans in causing the recent continental warming emphasizes the need to generate reliable projections of ocean temperature changes over the next century, in order to generate more reliable projections of not just the global mean temperature and precipitation changes (Barsugli et al. 2006), but also regional climate changes.”
Roger Pielke writes in his blog:
This is a major scientific conclusion, and the authors should be recognized for this achievement. If these results are robust, it further documents that a regional perspective of climate variabilty and change must be adopted, rather than a focus on a global average surface temperature change, as emphasized in the 2007 IPCC WG1 report. This work also provides support for the perspective on climate sensitivity that Roy Spencer has reported on in his powerpoint presentation last week (see).
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I begin to wonder how many legs AGW has to stand on. It seems that they keep being knocked from under the hypothesis.
Bill Derryberry
There was a significant El Nino event in 1878. Despite the “global warming” of the past 150 years, temperatures in 1878 were actually higher than the measurements of today. In just 14 months, there was a temperature swing of more than 1.0C globally.
The El Nino of 1998 caused an increase in global temperature of 0.75C (in less than one year). The La Nina of 2007 dropped temperatures by roughly the same 0.75C.
I don’t see how this variability can be so easily discounted by the warmers. I don’t see how this variability can be explained by GHGs.
Ok, stupid question here. How can I tell if this paper has been peer reviewed and approved?
Bill in Vigo
I listened to the senate hearings chaired by Barbara Boxer, facts are ignored and it is already decided. There is much work to be done if science and reality are to prevail.
Hyon
I have a problem with using SURFACE temperatures as the surface temperature does not reflect the heat content of the water beyond the surface. The surface temperature is often more of an indication of wind speed blowing across the surface than heat content of the ocean.
In other words, say I have 80 degree water at 40 foot depth in two different locations. One location has no wind blowing across the surface and the other location has a 15mph trade wind. The surface temperatures are going to be quite different even though the water column has the same heat content.
In other words, take tropical storms, for example. Sea surface temperatures are required to be a certain temperature ( think it is 86F but don’t hold me to that) to cause formation of a storm but the intensification potential relies on the heat content at depth. It’s called the Tropical Cyclone Heat Potential. And is measured in kJ/cm**2
If the warm water does not extend much below the surface, the wind from the storm itself will cool the surface water to the point to limit intensification. In order to keep the storm building, the surface must stay warm as the wind speeds increase and that requires a lot of heat content below the surface.
Surface temperatures do not equate to heat content.
I guess I would have to say, that if Roger Pielke said, “that this is a Major Scientific Conclusion”, that it has been reviewed and approved by at least one “Significant Peer”.
In other, other words … surface temperature maps do not correlate to heat content of the water. They correlate more to wind patterns.
Does this paper dovetail scientifically with the imminent paper to be published by Spencer?
“…the observed SST variability may be misrepresented in the coupled models used in preparing the IPCC’s Fourth Assessment Report…”
“Given these and other misrepresentations of natural oceanic variability on decadal scales…”
Hansen should be notified of this misrepresentation, clearly “high crimes against humanity”, to use his words.
AGW has hardly anything left other than: “the world will come to an end EVENTUALLY”. But considering its media and political power, does that mean that much?
“Ok, stupid question here. How can I tell if this paper has been peer reviewed and approved?”
It was published in a peer reviewed journal: Climate Dynamics.
“It was published in a peer reviewed journal: Climate Dynamics.”
Ok, is there any way to determine who the reviewing peers were? That matters in many cases.
REPLY: Reviewers are usually not disclosed to the public or to the authors. – Anthony
Clever guy, using observed sst’s then taking out GHGs and aerosols. That was a fantastic move. Now they have evidence that the aerosols were just a crock to prevent the GHG’s from creating a runaway greenhouse effect in the models (even though they have observations that the aerosols were local and the global dimming idea was garbage in the first place). Now we’re getting somewhere… anyone wanna make any wagers about how much of the warming is GHG and how much is natural? I want .006deg. C per decade for anthropogenic warming in the past 150 years.
Hah! all of you sun-worshipers!
We, the sea witches, rule!
Yeah, yeah, you can have yer dang major minimums, but thats just aberration. Mere aberration.
WE rule the multidecadal cycles, and don’t you forget it!
(Har-har. Arrrr. Shiver me timbers. Avast, ye hearties. And other comments. I shall now sing a sea shanty.)
Ok, stupid question here. How can I tell if this paper has been peer reviewed and approved?
Well, it bein’ Cap’n Silverpate ‘n’ First Mate Blacktooth, Bos’n Pegleg, and the rest of the Fo’c’s’tle gang. Arrrr.
This illustrates to perfection a point I’ve made here before. The whole of our climate system is far more complex than seems to be considered in the models as presently constructed {for all the use they have as predictive tools}.
I don’t doubt that an AGW proponent would want to jump on this to say that CO2 also causes oceans to warm, leading to greater land surface warming; however, these bodies warm in a different fashion than the atmosphere. And even if CO2 was to warm the atmosphere, the warmer atmosphere would not have much of an impact on the ocean’s heat content {I’m thinking here of the article on the hot water bottle effect by Stephen Wilde over on CO2 Skeptic}. So, if the oceans are warmer, and CO2 can’t be the driver here, why are the oceans warmer? :8)
Also, as Anthony notes above, any attempt to understand the climate must include the effects of such cyclic phenomena as the PDO and AMO. And for this, much more work is needed; it’s only been a dozen years since the PDO was clearly identified and its cyclic nature roughly mapped out. How can climate work succeed if the effects of the oceans are not understood. Even more is the necessity to come to terms with an understanding as to why the oceans experience these warm and cool phases and, most importantly, what triggers the changes. Without such an understanding of the oceans’ effects as well as coming to grips with the complexities of cloud formation and their effects, climate projections are little more than a computerized version of temple priests divining the future through their study of animal entrails.
We knowed it was them thar hydrodynamic-radiative teleconnections, primar’ly by moistenin’ and warmin’ th’ air over land and increasin’ the downward longwave radiation at th’ surface, we did. ‘Swat we allus said.
Thoroughly pier reviewed.
The point is that the oceans have been cooling (both sst’s and upper ocean heat content) since 2003. THAT IS NOT AN EXPECTED RESULT OF THE GREENHOUSE EFFECT!!!
Think of it as a C change vis sea change.
Evan Jones:
That is funny and all, but are you drunk, or is AGW hysteria finally gotten into your head?…..or both? 😉
Someone finally noticed the 800 lb gorilla in the room.
Damn, basic geology. Who would of thought the oceans mattered?
The oceans are not only our salt sink, trash sink, sediment sink, among others, it is also our heat and carbon sink.
And a huge sink it is. 71%? of our planet’s surface. To realize that the oceans play a role in the earth’s climate is rudimentary.
Isn’t it?
Mass of Atmosphere-5.1480×10^18 kilograms
Mass of Ocean-1.4×10^21 kilograms
(5.148×10^18)/(1.4 × 10^21)=0.003677143 or .37%
’nuff said.
(I’m actually surprised it’s that close.)
It seems a pity that they didn’t make the cut to two data sets around 1976 when the PDO change occurred. I recollect reading that after this “Great Pacific Climate Shift”, the upwelling of the Peruvian Current reduced by around 25%, equivalent to 12 Sverdrups, a huge change in upwelled cold water. While we don’t understand the origins for such changes, they undoubtedly reverberate through the oceanic cycles, perhaps sustaining a PDO direction.