Thursday, September 09, 2010

Roger Pielke snr elaborates

wrt, my previous post (the most reliable measure of AGW), I didn't explain that I read the Pielke snr paper because of a dialogue between him and a guest writer, gpwayne, at Skeptical Science, a site which focuses on review of peer reviewed papers about global warming . Subsequently, The Skeptical Science dialogue has become more interesting since in a follow up post by gpwayne Pielke snr has robustly joined the conversation and posted several comments to the thread. The relevant post is Pielke Sr and scientific equivocation: don't beat around the bush, Roger. Pielke snrs comments are # 15, 26, 35, 40, 48, 49, 64, 66, 83, 86, 94, 100, 109, 114, 115, 156, 157, 160, 167, 171, 173, 186, 194

Here are some extracts, the SUBHEADINGS are mine

EXPLANATION OF OCEAN HEAT MEASURED IN JOULES BEING THE BEST MEASURE OF GLOBAL WARMING
#15
A simple analog is a pot of water on the stove. When the burner is on, heat is added in Joules per second which results in the temperature increasing. By measuring the total heat of the water in the pot at any time, we can diagnosis the average rate of heating between sampling times. This integrated assessment is much more accurate than seeking to measure the heating rate itself.

In terms of the climate system, the heating rate is the global average radiative imbalance (which is made up of the radiative forcings and feedbacks). The difficulty of monitoring the fluxes, as contrasted with the integrated heat changes, is discussed in a series of weblog posts involving Kevin Trenberth and Josh Willis on my weblog...

"[T]here are several major reasons that the assessment of the earth system’s heat budget is so valuable.

• The earth’s heat budget observations, within the limits of their representativeness and accuracy, provide an observational constraint on the radiative forcing imposed in retrospective climate modeling.

• A snapshot at any time documents the accumulated heat content and its change since the last assessment. Unlike temperature, at some specific level of the ocean, land, or the atmosphere, in which there is a time lag in its response to radiative forcing, there are no time lags associated with heat changes.

• Since the surface temperature is a two-dimensional global field, while heat content involves volume integrals, as shown by Eq. (1), the utilization of surface temperature as a monitor of the earth system climate change is not particularly useful in evaluating the heat storage changes to the earth system. The heat storage changes, rather than surface temperatures, should be used to determine what fraction of the radiative fluxes at the top of the atmosphere are in radiative equilibrium. Of course, since surface temperature has such an important impact on human activities, its accurate monitoring should remain a focus of climate research (Pielke et al. 2002a).”

The recent data (2004-2008), according to Josh Willis, is quite robust in showing no global annual averaged upper ocean warming.


GLOBAL WARMING IS A SUBSET OF CLIMATE CHANGE, THEY ARE NOT SYNONYMOUS
#26
On the issues, you seem to be assuming that climate change is synonymous with global warming. Global warming, however, is a subset of climate change.

"Global warming" occurs when Joules accumulate within the climate system, of which the oceans is the largest reservoir for heat changes within the climate system.

I agree that other climate indices have changed (e.g. Arctic and Antarctic sea ice), but these are not direct measures of global warming. ...

GLOBAL WARMING HALTED FROM 2004-2008

... the statement such as "there was no global average warming in the upper ocean from 2004 to 2008" are consistent with his analysis. If they find an error, of course, that would need to be changed, but until it is, it is a robust, peer-reviewed scientific finding.

I still feel you are missing my main point. With all of the remaining unresolved uncertainties and systematic biases in the land surface portion of the multi-decadal global surface temperature trend ... we should move towards the more appropriate global warming metric of heat which is Joules, most of whose changes occur in the ocean. The ocean below 700m does not seem to be a major reservoir for this heat, as discussed in the web posts I sent in my first Comment.

IPCC MODEL PREDICTIONS NOT ACCURATE

Even with the remaining issues with the quantitative accuracy of the ocean heat content measurements, it should become the primary metric to diagnose global warming and as a measure to compare with the IPCC models. Until about 2004, the comparisons between the GISS model and the upper ocean heat content changes, for instance, were quite good ...

Since 2004, however, the model predictions have not been as good. Perhaps, this is a short term effect associated with natural variability. If so, we should see a resumption of heating rates that were seen up to 2004. This comparison with models, as a test of their accuracy, is the basic scientific method of hypothesis testing.

# 40
The statements that "global warming halted on this time period' and "global warming of upper ocean halted on this time period' both are correct ... (for the time period 2004-2008)

A PARTICULAR CAUSE FOR CONCERN ABOUT CO2 IS BIOGEOCHEMICAL EFFECTS

... to conclude that I have ever not been concerned about the addition of CO2 and how it affects the climate system misrepresents my perspective. I am particularly concerned with respect to the biogeochemical effects of added CO2 ...

WE DON'T FULLY UNDERSTAND THE CLIMATE SYSTEM

This does not mean that future global warming will not occur. However, to better understand the climate system, we need to understand why this halt occurred. Moreover, we need to see if in the coming years the heating will be amplified so as to catch up to the model predictions.

GLOBAL WARMING HAS OCCURRED OVER THE PAST 50 YEARS
#160
From all of the available evidence, time slices for today compared with 50 years ago clearly indicate that the upper ocean is warmer at present. Also, the OHC time changes is by far (~80%) the largest reservoir of global warming and cooling and can be used to diagnose the annual average global radiative forcing in Watts per meter squared.

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