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Tom Quirk

A Note on Temperature Anomalies by Tom Quirk

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One of the most vexing things about climate change is the endless debate about temperatures. Did they rise, did they fall or were they pushed? At times it seems like a Monty Python sketch following either the Dead Parrot or the 5 or 10 Minute Argument.

However it is possible to see some of the issues by looking at the correlation of the five temperature series that are advanced by the uppers or the downers.

The five groups are:
1. GISS, The Goddard Institute, home of James Hansen,
2. NCDC, The National Climate Data Center, a part of NOAA (as is GISS), the National Oceanographic and Atmosphere Administration.
3. BMO/UEA, The British Meteorological Office and the University of East Anglia.
4. UAH, The University of Alabama, Huntsville, home of Roy Spencer with his colleagues including John Christy of NASA and
5. RSS, Remote Sensing Systems in Santa Rosa, California, a company supported by NASA for the analysis of satellite data.

The first three groups use ground based data where possible with a degree of commonality. However since 70% of the surface of the earth is ocean and it is not monitored in a detailed manner, various recipes are followed to fill the ocean gap, if that is the best way of putting it.

The last two groups use satellite data to probe the atmosphere and with the exception of the Polar Regions which are less than 10% of the globe, they get comprehensive coverage.

One question is of course are the two groups measuring the same temperature? After all the satellite looks down through the atmosphere, while the ground stations are exactly that.

One of the ways to probe this is to look over time at the degree of correlation achieved in the measurements of the “global temperature anomaly

The results of such a comparison are given in Table 1 for the monthly time series from 1979 to 2008. There is the Pearson correlation coefficient extracted from the data. A value of 1.00 shows the compared values move in step with each other while a value of 0.00 would give complete independence. (A value of-1.00 is also possible.) “Commonality”, the square of the correlation coefficient is interpreted as showing what proportion of one measurement series is covered by the other series. Note that correlation does not imply connection or causality except that we know there is some commonality with ground based measurements.

Table 1.
Tom Quirk_table1_temp.JPG

First a check of the land based measurements shows that two groups are closely aligned, the difference reflecting the different processing to get the global result.

GISS is more problematic with less commonality which must be a reflection of quite different processing assumptions to that of NCDC or BMO/UEA.

For land based measurements we are faced with a “Judgement of Paris” and it is not clear who gets the Golden Apple.

Finally the satellite measurements have a high internal commonality but a commonality of some 50% with the land based measurements.

None of this should be surprising. The land measurements are on the land and subject to a number of uncertainties, such as heat island effects and lack of extensive ocean measurements while the satellites probe the atmosphere but not ground level.

So for the last 8 years the results are in Table 2

Table 2.
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It is surprising to see the agreement achieved by two quite independent approaches.

However we should be aware that none of this is simple.

Tom Quirk
Melbourne

Tests of the Sensitivity of the Atmosphere to Variations in Green Houses Gases by Tom Quirk

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General Circulation Models (GCM) used to forecast the future evolution of the atmosphere do not properly cover many of the important features of the last fifty years. This raises serious questions about their ability to predict future climate development with a precision that will be of use to policy makers.

The following are a simple and a sophisticated test of modelling the atmosphere.

First an analysis of regions with enhanced sensitivity to changes in CO2 concentration. These are found by comparing regions of varying concentrations of water vapour but constant CO2 concentration where changes in green house gases vary the amount of radiation directed downwards from the atmosphere to the surface. This should show changes in surface temperature as the global CO2 concentration increases with time.

This is followed by a test of the latest GCM models against measurements.

The amount of CO2 in the atmosphere has risen substantially in the last fifty years but it has been difficult to isolate its contribution to the world temperature rise that has occurred in that time.

A continuous stream of high quality measurements show the concentration of CO2 in the atmosphere has risen from 316 ppmv in 1959 to 382 ppmv in 2006. This is an increase of 21% in some fifty years. At the same time the global temperature has increased by 0.5 to 1.0 0C.

There are large variations in water vapour in the atmosphere with a maximum at the equator and minima at the poles. In addition there are bands of latitude where the seasonal temperature variations are small as the ocean interacts with the atmosphere. These should be regions where the effects of global changes in CO2 concentration are more obvious in year on year variations as other climate variations are reduced.

The damping of seasonal temperature change can be seen from Figure 1 showing the maximum variations of temperature as a function of latitude averaged over the years 1948 to 2006.

Figure 1
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Two latitude bands were selected for analysis, the band 4 to 9 N in the tropics and the band 51 to 56 S in the Southern Ocean.

The tropical band surface is 75% ocean while the Southern Ocean band is 99% ocean. As a comparison, the band 51 to 56 N is only 40% ocean and has substantial seasonal variations.

The mean monthly temperatures are shown below averaged over the years 1948 to 2006 in Figures 2 and 3

Figure 2:
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Figure 3
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The variations are 0.8 0C in the Tropics and 4.0 0C in the Southern Ocean

The variations in the mean annual humidity are shown below in Figure 4:

There is a 70% reduction in water vapour in moving from the Tropics to the Southern Ocean with a consequent enhancement of the contribution of CO2 to the downward directed radiation from the atmosphere.

The seasonal variations show that humidity remains relatively stable in the two latitude bands chosen for analysis. This is not the case for the equivalent Northern latitude band where there is a factor of five seasonal change in humidity.

Figure 4
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The mean annual temperatures for the Tropical band are shown below in Figure 5.

Figure 5
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A simple straight line has been fitted to the temperatures although there is clearly some detailed short term structure present such as ENSO. The Southern Ocean temperatures have also been treated in the same way.

The linear gradients from the least squares fits are given in the Table 1

Table 1
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The Southern Ocean temperatures are better described by a temperature increase for 1948 to 1976 and then a constant temperature. However as with the Tropical temperatures, there is clearly some short term structure seen in Figure 6.

Figure 6
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The analysis shows the tropical temperature increase is substantially larger than the Southern Ocean increase.

The MODTRAN computer programme has been used to give a simple indication of the changes in downward radiation from the atmosphere to the surface. Relative humidity is held constant and temperatures and the water vapour scale adjusted to the measured values.

The temperature increases have been calculated using MODTRAN and assuming a latent energy contribution at the surface. The latent energy term is a function of surface temperature and reduces the temperature rise by a factor of two.

The results are shown in Table.2

Table 2
table2_climate_tests.JPG

The calculations show that for increased CO2 there is a larger increase in downward radiation in the Antarctic region compared to the Tropics. This is also the case for a doubling of CO2 concentration in the atmosphere. Feedback effects have been included in the final results shown below in Table 3.

Table 3
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Thus a simple calculation gives a larger temperature increase in the Antarctic region over the Tropics. However the atmosphere has energy transfer processes that may explain the apparent contradiction.

General Circulation Models (GCM) take into account many energy transfer processes and are used to forecast climate temperature changes. Many of these models are calibrated against past measurements of a number of atmospheric variables. Two models that offer access to their results have been examined with data taken from the GISS and GFDL websites. Both are members of the IPCC group listed at the LLNL website.

GCM surface temperature profiles for the fifty years from 1950 to 2000 were downloaded and the map longitude-latitude grid point temperatures averaged around latitude circles.

Surface temperature measurements were taken from the NCAR website and for comparison 5 year means have been used with temperatures averaged in latitude bands.

The results of the comparisons are shown below in Figure 7 for the Goddard Institute for Space Studies GCM with a coupled atmosphere-ocean. Data was downloaded for all forcings combined for the 1880-2003 Climate Forcings.

Figure 7
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A similar comparison has been made for the Geophysical Fluid Dynamics Laboratory (Princeton) CM2.X Coupled Climate Model. The results are also shown below in Figure 8 and an overall summary is given in Table 4.

Figure 8
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Table 4 – Global Temperature Changes
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While the global values are consistent with the measurements, in detail the calculations are not supported by measurements. There are different responses at the North and South Poles and a complicated response in the latitudes 60 S to 60 N.

The GCM’s are closer to the measurements than the simple MODTRAN calculation. This demonstrates the importance of many processes other than the CO2 forcing. However the comparisons show that these processes do not seem to have been adequately modelled to date.

The contribution of increasing CO2 concentrations is not detectable with this analysis. This is not to doubt that it has an effect but that there are other processes also at work in the atmosphere ocean system that tend to dominate.

However the confidence with which the future predictions are presented coupled with the obvious mismatches with the past are an echo of the Soviet era Polish saying: “The future is certain only the past is unpredictable”.

Tom Quirk
Melbourne

Waste Not, Want Not: A Note from Tom Quirk on Nuclear Waste Disposal

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The mining of uranium and the disposal of spent fuel are the largest components of the costs in the uranium fuel cycle.

The disposal of long-lived radioactive waste within Australia could be one of the single biggest contributions we can make to the safety of our region, and even the world.

Domestically, Australia produces about 45 cubic metres – three truckloads – per year of low and intermediate level radioactive wastes. Much of this material is produced in the research reactor at Lucas Heights, then used at hospitals, industrial sites and laboratories around the country.

There are about 3,700 cubic metres of low-level waste stored at over a hundred sites around Australia. Over half of the material is lightly-contaminated soil from CSIRO mineral processing research. In addition there are about 500 cubic metres of long-lived intermediate level waste.

But having dispersed storage is not considered a suitable long-term strategy for the safe storage of waste. So the Federal Government has proposed a consolidation to a single repository site.

The plan is for a disposal area about 100 metres square within a two square kilometres area.
Low-level and short-lived intermediate level wastes would be disposed of in a shallow, engineered repository designed to contain the material and allow it to decay safely to background levels.

Intermediate-level wastes with lifetimes of greater than 30 years would be stored above ground in a facility designed to hold them secure for an extended period and to shield their radiation until a geological repository is eventually established, or alternative arrangements made.

Contrary to popular belief, this proposal is not about the ultimate disposal of high-level radioactive waste from the spent fuel of reactors.

The high level wastes produced by nuclear power stations are not yet a concern. If we are lucky we might have two operating nuclear power stations within 20 years. But we would not then be worrying about waste from them for another 50 years.

Even so, it may be with cheap coal and carbon dioxide burial – what we grandly call geosequestration – that we find conventional power plants are the better buy.

Currently, the concern is about the disposal of industrial waste, an area where governments have had great difficulties in finding acceptable solutions.

So what is the fuss about?

There is a worry about instability caused by earthquakes. Helen Caldicott in ABC News Opinion on Monday expressed concern that the Federal Government’s preferred site for a waste dump experienced recently a quake measuring 2.5 on the Richter scale.

However, an earthquake of this magnitude is classified as detectable but generally not felt. There are about 1,000 earthquakes of this intensity each day all over the earth. It might not even cause a ripple in your café latte.
Enrichment and reprocessing may provide further business opportunities. In this area, Australian scientists have made major technical contributions. But firms require access to large amounts of capital to pursue their development. None of our major mining or energy companies has expressed, at least recently, any desire to enter these markets.

The mining of uranium and the disposal of spent fuel are the largest components of the costs in the uranium fuel cycle. Australia could benefit from providing both services.

Indeed, there could be significant regional demand. Thailand, China and India might find an Australian waste storage facility extremely attractive. Countries that are genuinely earthquake prone, as Japan and Indonesia are, would no doubt welcome an opportunity even more.

Australia provides its reputation, its technical expertise and its high-quality infrastructure for all manner of services to Asia-Pacific region. We should not be blind to the potential of a waste storage facility.

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This piece was first published by ABC Online and is republished here with permission from the author. Tom Quirk is a member of the board of the Institute of Public Affairs and chairman of Virax Holdings Ltd, a biotechnology company. He is a nuclear physicist by original training.