Download on global warming and the role of fossil fuels

ON GLOBAL WARMING AND THE ROLE OF FOSSIL FUELS
Dr. L.K.Walker BE, PhD (Cantab), MBA, FAusIMM
1. Introduction
The volume and technical diversity of material written on global warming, on the impact of
human activity on greenhouse gas levels, and the consequences for the future of civilisation
make it difficult for anyone to form a balanced view on the issue. In addition, the debate has
become highly technical, politicized and increasingly acrimonious. On the one hand, there is
the so-called “consensus” view favoured by the Intergovernmental Panel on Climate Change
(IPCC), on the other, a “sceptical” or “rationalist” view offered by a range of well-qualified,
independent scientists. These circumstances make it essential that professional “non-climate
scientists” develop a sufficient understanding of the issue for them to offer guidance for the
future planning of the world economy.
One way to attempt this task is to focus on the logic of the key issue at hand – which is
“what is the evidence that fossil fuel burning on earth is the cause of temperature rises this
century and what, if any, are the implications for the future?” In order to put the discussion
into a consistent framework, reference will be made to data and commentary provided in the
IPCC Report “Climate Change 2001: The Scientific Basis” (IPCC 2001), which represents a
widely accepted version of the scientific community’s position on global warming.
2. Global Warming in the Last Century
The currently accepted record of world average temperature change as it relates to 20th
century global warming, after Jones et al. (2006), is represented by Figure 1 This graph is
based on an averaging of several thousand worldwide weather station records, and shows
that the last century was characterised by two periods of warming, between 1907-1941 and
1975-2001, separated by an interval of cooling during 1941-1975.
FIGURE 1 Average Global Temperature Record (IPCC Fig. 2.1(a) updated)
It is worth noting that 2005 was not the hottest year in the last 100 years, as often
reported in the media, one result of which is that mean temperature has not increased
since 1998. In its Summary for Policymakers, IPCC (2001) concludes from the evidence
it presents that “The global average surface temperature has increased over the 20th
century by about 0.6°C”. This statement is true as far as it goes, but ignores the
significance of the intermediate trend down from 1940 to 1975, and the post-1998
evidence of flattening.
3. Temperature and Carbon Use Correlations
Establishing the evidence for a link between anthropogenic (man-made) fossil fuel
burning and temperature changes has been made more difficult by the focus on CO2 as an
intermediate variable. IPCC (2001 – Fig 3.3) presents a graph showing both fossil fuel
usage and CO2 level increases and concludes that “Current anthropogenic emissions of
CO2 are primarily the result of the consumption of energy from fossil fuels.” IPCC also
concludes that “Detection and attribution studies consistently find evidence for an
anthropogenic signal in the climate record of the last 35 to 50 years”. In other words,
CO2 levels have gone up with fossil fuel use over the last 50 years, and new modelling
studies have been able to correlate these CO2 level changes with temperature changes.
It is evident that deterministic computer models can be massaged to reasonably reproduce
the global temperature pattern of the last 100 years. However the IPCC report (Section
12.2.3), properly (and despite the extent to which models are used predictively in policy
presentations) summarises some of the problems of model construction as follows
“Different models may give quite different patterns of response for the same forcing, but
an individual model may give a surprisingly similar response for different forcings.”
And again in Section 7.3, “……..considerable uncertainties still exist concerning the
extent to which present climate models correctly describe the oceanic response to
changes in the forcing.” In addition, there does not appear to have been a significant
attempt to calibrate the computer models to reflect past long-term glacial cycles, which
would appear to be essential if they are to fairly represent the impact of natural factors.
This modelling approach assumes that CO2 levels drive temperature changes. However
strong evidence exists to the contrary. De Freitas (2002) reports on a number of
independent statistical analyses that conclude that the reverse is true, namely that
temperature changes precede CO2 level changes, calling into question the basis of the
modelling procedure.
The IPCC study does not attempt to directly correlate fossil fuel usage with temperature
changes over a long period of history. It is therefore instructive to compare fossil fuel
usage from published data directly with the global temperature changes shown on Figure
1. The following points (extracted from Figure 2 below) should be noted.
Consider three equal time intervals and the two variables, temperature and fossil fuel use.
o
o From 1910 to 1940, the global temperature rose 0.4 C, and the average annual
fossil fuel usage was about 2 billion metric tonnes of carbon
From 1940 to 1970, the global temperature declined by 0.2oC, and the average
annual fossil fuel usage increased to about 4 billion metric tonnes of carbon
o
o From 1970 to 2000, the global temperature again rose 0.4 C as for 1910-1940, but
this time the average annual fossil fuel usage was about 9 billion metric tonnes of
carbon, nearly five times higher
o
In a relevant statistical analysis, Klyashtorin and Lyubushin (2003) concluded that from
the 1860’s to the present, world fuel consumption and temperature changes (Figure 2)
underwent a 50-60 year cycle of positive and negative correlations, that this cyclic trend
was evident from ice core data going back 1500 years, and that a further cycle of cooling
was imminent.
Based on the available evidence, both of the key IPCC model assumptions, that global
warming is driven by CO2 and caused by fossil fuel usage, thus remain unsubstantiated.
FIGURE 2 Fossil Fuel and Temperature Variations with Time
4. Past Climate History
It is unrealistic to look at the last century’s temperature changes without placing it in the
context of historical evidence. Figure 3 (from IPPC 2001) presents ice core data over the
past 400,000 years showing variations in temperature, CO2, and CH4, a period when
fossil fuel usage by today’s standards was effectively zero. Not only are the repetitions
of the cooling/warming cycle striking, but a broad correlation in change of the three
parameters appears evident. However the CO2 levels (200-300ppmv) are very low
compared to earlier geological times – IPPC Figure 3.2 indicates that levels of 6000ppm
existed 200 million years ago, due presumably to natural causes. Analysis of the ice core
data has also shown that CO2 level changes precede temperature changes (De Freitas
2002).
FIGURE 3 Variations of temperature, methane, and atmospheric carbon dioxide
concentrations derived from air trapped within ice cores from Antarctica (IPCC Fig.
2.22)
The IPCC Report puts aside the significance of natural geological climatic changes in
temperature and CO2 as being too slow to be of relevance. However in Section 2.4.3 it
addresses the question “How Rapidly did Climate Change during the Glacial Period?”,
this covering the period after the last peak of glacial conditions which occurred between
about 25 to 18ky BP. In particular, the Report states that “very rapid warming at the
start of the Bölling-Alleröd period (14.5 to 13ky BP), or at the end of the Younger Dryas
(12.7 to 11.5ky BP) may have occurred at rates as large as 10°C/50 years for a
significant part of the Northern Hemisphere”. Again in an earlier paragraph, it states
“The warming phase, that took place about 11,500 years ago, at the end of the Younger
Dryas was also very abrupt and central Greenland temperatures increased by 7°C or
more in a few decades”.
And so wide and very rapid changes in temperature, as well as wide changes in CO2,
have been part of the past natural order. The 70C rise in northern hemisphere
temperatures, in a few decades 11,500 years ago, dwarfs the rise of 0.6 0C in average
global temperature in the last century, but showed a comparable rise in CO2 levels of
around 150ppm. Factors other than CO2 level must clearly have driven these rapid
temperature changes.
5. Summary
The bulk of publications on global warming focus on:
o Interpretation of current and past (proxy) temperature data to determine the extent of
global warming occurring over the past century and past millennium
o Debate on the impacts of current and future increases in global temperature,
projected using deterministic computer modelling – eg. sea levels, weather patterns
and their volatility, flora and fauna etc
o Further development of the computer models to try and better reflect current
understanding of global weather processes.
Within all of this information, it is surprisingly difficult to find a coherent presentation of
the argument that asserts that global temperature increases are linked to fossil fuel use,
which is the cornerstone of logic behind the Kyoto agreement. This link is made more
complex because of the insertion of CO2 levels as an intermediate step between these two
variables.
The historical data involving these variables can be summarised as follows.
o During the past century, when annual fossil fuel consumption has grown from
near zero to nearly 12 billion tonnes of carbon, global temperatures have
increased overall by a modest 0.6 0C, and in a number of phases that do not
correlate with the growth in fossil fuel use.
o In geological times past, with effectively no impact from man-made carbon
emissions, global temperatures changed rapidly by many degrees in a few
decades, and changes in temperature preceded, rather than responded to, parallel
changes in atmospheric CO2.
It can only be concluded that there is no demonstrated evidence that links fossil fuel use
to global temperature increase, and that the dominant effects of natural factors are still in
play.
6. Conclusion
From the above brief review, it must be stressed that no consistent logical basis exists for
the current “consensus” view that fossil fuel usage is largely the cause of global warming.
Rather, the modest temperature increases of the past century may well result from natural
causes alone. A concerted attempt to address this logic, and to understand the natural
climate drivers in past glacial cycles, is essential before economic decisions of
international significance are taken based on a fear of uncontrolled future global
warming.
This fear might be expressed by the following quotes:
“There are ominous signs that the earth’s weather patterns have begun to change
dramatically…”
The evidence in support of these predictions has now begun to accumulate so massively
that meteorologists are hard-pressed to keep up with it.”
“Climatologists are pessimistic that political leaders will take any positive action to
compensate for the climate change, or even allay its effects”
These quotes, extracted from an article in Newsweek, April 28, 1975 titled “The Cooling
World”, might have been written recently in connection with global warming fears. That
the so-called “consensus” scientific view could have completely reversed in only 25 years
is of itself a grave warning to community leaders to consider the facts carefully before
committing to decisions with immense long-term consequences.
References
de Freitas (2002) “Are Observed Changes in the Concentration of Carbon Dioxide in the
Atmosphere Really Dangerous”. Bulletin of Canadian Petroleum Geology, Vol 50, No.
2, pp297 - 327
IPCC (2001) “Climate Change 2001:The Scientific Basis” Houghton, J.T., Ding, Y.,
Griggs, D.J., Noguer, M., ven der Linden, P.J. and Xiaosu, D. (eds.). Cambridge
University Press
Jones, P., and Palutikof, J.(2006) “Global Temperature Record” Climate Research Unit,
University of East Anglia, www.cru.uea.ac.uk/cru/info/warming
Klyashtorin, L.B., and Lyubushin, A.A. (2003) “On the Coherence between Dynamics of
the World Fuel Consumption and Global Temperature Anomaly”. Energy and
Environment, Vol 14, No. 6, pp773 - 782