Compo and Sardeshmukh: Oceans a main driver of climate variability - it’s the heat AND the humidity.

Compo and Sardeshmukh: Oceans a main driver of climate variability - it’s the heat AND the humidity.

23 07 2008

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.”

Beck on CO2 and Temperature: Oceans are the “dominant CO2 store”

Beck on CO2 and Temperature: Oceans are the “dominant CO2 store”

25 07 2008

Evidence of variability of atmospheric CO2 concentration during the 20th century
Geo-Ecological Seminar University of Bayreuth, 17th July 2008 (see here)
Ernst-Georg Beck, Dipl. Biol

Click for larger image with interactive popup links

Summary of the presentation (printable PDF available here)

In 1958 the modern NDIR spectroscopic method was introduced to measure CO2 concentrations in the atmosphere [Beck 2007]. In the preceding period, these measurements were taken with the old wet chemical method. From this period, starting from 1857, more than 90,000 reliable CO2 measurements are available, with an accuracy within ± 3 %. They had been taken near ground level, sea surface and as high as the stratosphere, mostly in the northern hemisphere. Comparison of these measurements on the basis of old wet chemical methods with the new physical method (NDIR) on sea and land reveals a systematic analysis difference of about minus 10 ppm.

Wet chemical analyses indicate three atmospheric CO2 maxima in the northern hemisphere up to approx. 400 ppm over land and sea since about 1812. The measured atmospheric CO2 concentrations since 1920 –1950 prove to be strongly correlated (more than 80 %) with the arctic sea surface temperature (SST).

A detailed analysis of the Atlantic Ocean water during the arctic warming since 1918 – 1939 by Wattenberg (southern Atlantic ocean) and Buch (northern Atlantic ocean) indicates a very similar state of the Atlantic Ocean (pH, salinity, CO2 in water and air over sea etc.) These data show the characteristics of the warm ocean currents (part of global conveyor belt) at that time, indicating a strong CO2 degassing from the Atlantic Sea, especially in the area of Greenland/Iceland and Spitsbergen. More than 360 ppm had been measured over the sea surface.

In 2004 Polyakov published evidence for a multi-decadal oscillation of the ocean currents in the arctic circle, showing a warm phase (strong arctic warming during 1918 –1940 with high temperatures in the Iceland/Spitsbergen area) similar to the current situation, and a cold phase (around 1900 and 1960). Today the Iceland/Spitsbergen area is known for a strong absorption of CO2.

This multi-decadal heating of the oceanic CO2 absorption area and larger parts of the Northern Atlantic Ocean was followed by an increase of the atmospheric carbon dioxide concentration to approx. 400 ppm during the 30s and approx. 390 ppm today. The abundance of plankton (13C) and other biota supports this view.

Who knew? Rachel Carson - climate change expert

Who knew? Rachel Carson - climate change expert

25 07 2008

NOTE: For those of you who don’t know, Rachel Carson has often been hailed as the “mother of the environmental movement” due to her book, Silent Spring, which is said to have resulted in the banning of the pesticide, DDT, worldwide. Before that book, she wrote another, The Sea Around Us, in which she proposes mechanisms for climate change.

What is most interesting is that, unlike with DDT, there is no placing blame on climate change to human influence. The mechanisms she proposes are all natural, all cyclic variation. No human created chemical influence (CO2) is mentioned. I wonder what she’d say today? Would she flip-flop and go with the flow of the current CO2 movement?

From Ed Sanders website, with some slight editing for readability and removal of the maddening glowing red background. (h/t to Steve McIntyre for the link) - Anthony

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From the book, The Sea Around Us.

Copyright 1950, 1951, by Rachel Carson.

Reprinted by permission of Oxford- University Press, Inc.

The old-timers are right–winters aren’t what they were. And the reason may be gigantic tides deep under the sea that apparently change the climate of the whole earth.

The ocean comes alive in one of this year’s most fascinating books. This article is condensed from The Sea Around Us by Rachel Carson. A lilelong student of nature, Miss Carson is editor-in-chief of the U. S. Fish and Wildlife Service.

Day by day and season by season, the ocean dominates the world’s climate. Can it also be an agent in bringing about the long-period swings of climatic change that we know have occurred throughout the long history of the earth-the alternating periods of heat and cold, of drought and flood? There is a fascinating theory that it can.

This theory links events in the deep, hidden places of the ocean with the cyclic changes of eliminate and their effects on human history. It was developed by the distinguished Swedish oceanographer, Otto Pettersson, whose almost century-long life closed in 1941.