Climate Change




Using a gene-based biological approach, Salter (2003) estimates the relative investment that individuals allocate to their self, offspring, ethny and humanity. The table below shows that individuals are motivated to invest something like 3% of their resources into humanity as a whole (the numbers are merely indicative). This does not bode well for voluntary mitigation of climate change.


Annan, James





A 'Dutch book' is a gambling term for a set of odds and bets which guarantees a profit, regardless of the outcome of the gamble. At the very least, one who practices self-consistent reasoning should not be susceptible to having a Dutch book made against them. If an individual is not susceptible to a Dutch book, their previsions are said to be 'coherent'. A set of betting quotients is coherent if and only if they satisfy the axioms of probability. Science is essentially applied Bayesian inference, which involves putting probabilities on hypotheses. In other words, the concept of betting is fundamental to science. See Lindzen, Richard.


The fossil fuel/mining industry obviously have a vested interest in denying anthropogenic global warming. Journalists tend to simplify and exaggerate. Also, argument to moderation is a logical fallacy which asserts that a compromise between two positions is correct, which leads to a media bias towards 'balanced' reporting. On that basis, the media have given undue weight to the opinions of climate sceptics. Scientists tend to defend their own turf.



Business Action on Climate Change


Carter, Bob

Robert Carter is a committee member in the Institute for Public Affairs (IPA), an Australian free-market think tank that has received funding from the fossil fuel and mining industries. In his book Carter says that the recent global temperature rise terminated in 1998. Embarassing.




The entire Climategate episode was the result of a carefully orchestrated denial machine. The scientists have now been vindicated by no less than six independent investigations. ClimateSight: The Real Story of Climategate



Connolley, William

Until December 2007 William Connolley was Senior Scientific Officer in the Physical Sciences Division in the Antarctic Climate and the Earth System project at the British Antarctic Survey, where he worked as a climate modeller.


D. James Baker, administrator of the US National Oceanic and Atmospheric Administration, has said about global warming that ‘‘[t]here’s a better scientific consensus on this than on any issue I know—except maybe Newton’s secondlaw of dynamics’’ (Warrick, 1997, p. A1). Warrick, J., 1997. The warming planet; what science knows. The Washington Post, Washington, DC, November 11, p. A1.

'At the Future in Review Conference in San Diego last year, Harvard professor James McCarthy, former co-chair of the Intergovernmental Panel on Climate Change, was asked how many of the world’s top 1000 climate experts would disagree with the basic scientific consensus that the increase in greenhouse gas concentrations over the last 50 years to levels not seen in 650,000 years is primarily anthropogenic. He replied, “Five.” (He also told an amusing anecdote about a colleague being asked the same question at a conference and answering, “Ten.” McCarthy went up to him later and asked how he got to ten. The guy replied that he could only think of five – the same five as McCarthy – but doubled the number to provide a margin of error.) That is about as solid a scientific consensus as you are ever likely to get for such a complex set of phenomena. Yet it is almost an article of faith in Republican circles these days that the threat from global warming is at best greatly exaggerated and at worst a “hoax.”' source

Oreskes (2004) analysed 928 abstracts, selected using the keywords ‘global climate change’, published in refereed scientific journals between 1993 and 2003 and found that 75% explicitly or implicitly endorsed the theory of anthropogenic climate change, 25% dealt with methods or paleoclimate taking no position on anthropogenic climate change, and none of the papers disagreed with the theory of anthropogenic climate change.


IPCC (2007) implies that that we're not sure what the effect of contrails is, but are confident that the magnitude is small.

Debate, Climate Change

Delingpole, James

The Press Complaints Commission's ruling implies that Delingpole's commentary is 'clearly distinguished from fact'. Basically, Delingpole can only get away with posting nonsense because it is considered opinion and posted on a blog. See also Carbon Brief: Press complaints ruling on UEA, Delingpole and climate didn't stick to the science. Delingpole's posts on climate change are the worst I have ever seen on climate change associated with a broadsheet newspaper. He isn't a scientist and doesn't know anything about climate change. Watch him squirm here: YouTube: Climate change denier James Delingpole doesn't do science. James Delingpole's anti-science is so bad that he's almost good. For Delingpolegate, see: guardian.co.uk: James Delingpole leads Telegraph into vicious climate over email.

Denial, Climate Change

Denier vs Sceptic



Energy Lobby

The energy lobby dwarfs alternative energy interests.


Greenhouse gases are a negative externality. In the economic sense, the existence of externalities compromises overall social utility, so public policy should seek to internalize any externalities.


Our best estimate for the sum of the feedbacks is positive, see What Explains the Current Spread in Models’ Climate Sensitivity Estimates? - AR4 WGI Chapter 8: Climate Models and their Evaluation.

Fossil Fuels

The problem of global warming is both mitigated and complicated by the fact that fossil fuels are running out. Oil is expected to last another 43 years, gas 167 years and coal 417 years. See the table.

Peak in productionExpected to 'run out'
Oil 2007 2052
Gas 2025 2176
Coal2028 2426

Source: Wikipedia (2009)

Funding Climate Change Denial

There is evidence that most significant sceptics/deniers have connections with the fossil fuel industries. Global warming denial has been funded by the fossil fuel industry. Those affected included scientists, authors, the media and the US government.

ExxonMobil alone has ploughed more than $8 million into over 40 groups preaching scepticism. Also consider the (now defunct) Global Climate Coalition and the (active) Competitive Enterprise Institute. In fact, I've yet to come across a single well-known sceptic without either past or current connections to the fossil fuel industry, but in most cases I suspect that the scepticism came first, and the fossil fuel industry approached them on that basis. Here is some evidence of fossil fuel-funded denial.

Global Climate Coalition

The Global Climate Coalition was 1) influential and 2) closed down as the oil companies realised they were backing crank science. 1) 'President's George Bush's decision not to sign the United States up to the Kyoto global warming treaty was partly a result of pressure from ExxonMobil, the world's most powerful oil company, and other industries, according to US State Department papers seen by the Guardian.' 2) 'A major scientific report on the severity of global warming by the IPCC in 2001 led to large-scale membership loss.'

Graphics, Climate

Greenhouse gases

Greenhouse gasChemical formulaPreindustrial levelCurrent levelLongetivity in troposphere
Water vapour H2O 36-70%
Carbon dioxideCO2 9-26% 278ppm379ppm > 100 years
Methane CH4 4-9% 700ppb1774ppb < 10 years
Nitrous oxide N2O 275ppb319ppb 100 years
Ozone O3 3-7% a few days
CFCs various 0 0.707ppb

Sources: Henson (2008), Maslin (2009), Wikipedia (2009)

Halpern, Joshua

Joshua Halpern is a Professor of Chemistry and works in the area of physical chemistry, see Joshua B. Halpern.


The theory of anthropogenic global warming is built on peer reviewed science that has accumulated since Fourier in the 1820s. Concern about global warming began in the 1950s and escalated in the 1970s. . Arrhenius knew about positive feedback. Arrhenius believed that global warming would be beneficial to humanity. Take a look at Why is climate sensitivity so unpredictable? and scroll down to page 4. Arrhenius (1896)'s estimate for climate sensitivity of 5.5 °C was surprisingly close to modern estimates (2 to 4.5°C with a best estimate of about 3°C), and our uncertainty is not significantly decreasing.

Hockey Stick

The hockey stick shape of the temperature reconstruction has been confirmed by over a dozen subsequent scientific papers.




The IPCC distil peer-reviewed scientific research. Virtually all of the world’s governments belong to the IPCC, so there should be no bias towards countries that do or do not wish to mitigate or adapt to climate change.




Lindzen, Richard

Richard Lindzen is a highly qualified climate scientist. He has also been characterized as a contrarian, a strategy that gives him a slim chance of making a ground-breaking contribution to science, but a high probability of being wrong. Lindzen, Chou and Hou (2001) hypothesized that the Earth may act like an infrared iris, a hypothesis that suggests a negative feedback and low climate sensitivity. However, satellite data from CERES showed that the Iris effect would actually warm the atmosphere, implying that they were wrong. Scientists are human, and can cling on to their theories despite contrary evidence. Lindzen is clinging on to his conclusion of low climate sensitivity, and seeking evidence to support it. This can lead to poor science, science that Lindzen himself is not prepared to bet on (at fair odds), see Reason Magazine: Betting on Climate Change. 'Lindzen is on record as saying that global average temperatures could rise by 1 degree Celsius over the next century. In contrast, climate model projections predict a warming of 1.4 to 5.8 degrees Celsius by 2100' (source: Reason Magazine). 'Lindzen, for his part, charges oil and coal interests $2,500 a day for his consulting services; his 1991 trip to testify before a Senate committee was paid for by Western Fuels, and a speech he wrote, entitled "Global Warming: the Origin and Nature of Alleged Scientific Consensus," was underwritten by OPEC.'


Mailing Lists

McIntyre, Stephen

Stephen McIntyre is a former minerals prospector and semi-retired mining consultant.


There is a media bias of ‘balanced’ reporting. Argument to moderation (also known as middle ground, false compromise, gray fallacy and the golden mean fallacy) is a logical fallacy which asserts that a compromise between two positions is correct. On that basis, the media give undue weight to the opinions of climate sceptics. As another example of the effect of the fallacy, the MMR vaccine doesn't cause autism, but many people still think that there is a slight risk, because they imagine that there must be some truth in the original paper. One major difficulty with realising the threat is that the most important cause, carbon dioxide, can't be seen, smelled or touched. One way of persuading people that anthropogenic climate chnage is possible is to remind them just how thin the atmosphere is relative to the size of the earth.

Medieval Warm Period

Michaels, Patrick


There are three potential goals: stabilize emissions, stabilize concentrations or stabilize temperature. Broadly speaking, there are three approaches to dealing with the problem of global waming: adaptation, mitigation and geoengineering. Two popular solutions are a carbon tax and emissions trading (cap and trade). They are theoretically equivalent except that they're logically opposed regarding where the uncertainty lies: a carbon tax fixes the rate of taxation and allows emissions to vary, whilst emissions trading fixes emissions and allows the cost of compliance to vary.





Oil Industry

Peer Review

Peiser, Benny

Benny Peiser is a social scientist who has never published a single peer-reviewed article on climate change in his life (even his letter was rejected!), but did indeed retract some of his claims and his conclusion.

Physical chemistry

Physical science

The theory of anthropogenic global warming is built on peer reviewed science that has accumulated since Fourier in the 1820s. According to the IPCC, we are 99.8% certain that the total radiative forcing from anthropogenic agents is positive, see 2.9.2 Global Mean Radiative Forcing - AR4 WGI Chapter 2: Changes in Atmospheric Constituents and in Radiative Forcing. This is their best estimate obtained via assigning probability distribution functions to the individual radiative forcings and performing a Monte Carlo simulation. See Boucher and Haywood (2001) ("On summing the components of radiative forcing of climate change").


Ian Plimer is a director of three Australian mining companies. Plimer's book was widely criticized by scientists, described as science fiction and contains 'a hilarious series of schoolboy errors'.

Politics of Global Warming



Public opinion on climate change



RealClimate is recognised as the best website on the science of climate change, and is written by climate scientists, see RealClimate: Contributor Bio’s.

Romm, Joe

Joe Romm has an excellent reputation, see Wikipedia: Joseph J. Romm.

Sceptics, Climate

Scepticism is due to the energy lobby, free market think tanks, the media bias of 'balanced' reporting (argument to moderation), susceptibility to conspiracy theories and ignorance. The small number of sceptical scientists (e.g. Lindzen, Spencer) have spent much of the last decade searching for a negative feedback in our climate system, with the aim of showing that climate sensitivity has been grossly overstated by the IPCC. Some sceptics are simply confused old men. I suspect that most sceptics have faith in scientists when it really matters, such as having faith in mainstream medicine when seriously ill.

Schwartz, Stephen

Schwartz, et al. (2010) is currently unpublished (see ). Perhaps the authors avoided calculating climate sensitivity using paleoclimate data in case it undermined their conclusions? Or perhaps they underestimated the ocean thermal lag? See also . Their conclusion: 'Because of the great difference in atmospheric residence times of greenhouse gases and aerosols, the effect of the greenhouse gases will dominate long-term forcing and climate response. Even if the earth's climate sensitivity is at the low end of the IPCC estimated ``likely'' range, continued emission of CO2 at the present rate would exhaust in just a few decades the shared global resource of the incremental amount of CO2 that can be added to the atmosphere without exceeding proposed maximum increases in GMST.'


Science, in practice, progresses by peer review, and the IPCC assessment reports are arguably the most peer reviewed documents in the history of science. Science is cumulative, which is why the IPCC reports come out every six years.

Search Engine


Sensitivity, Climate

The sum of the underlying climate feedbacks is substantially positive which creates a system where uncertainty is inherent: small uncertainties in the feedbacks are highly amplified in the resulting climate sensitivity. The feedback factors for individual processes are linearly additive, but the temperature changes from individual processes are not. The resulting probability density function of climate sensitivity has a positive skew, and the shape is an inevitable consequence of the nature of the climate system. Reducing the uncertainties in the individual climate processes has little effect in reducing the overall uncertainty in climate sensitivity (the breadth of the distribution remains almost unchanged). Uncertainty in climate sensitivity estimates has not diminished substantially in the past 30 years, and the estimates are not expected to improve significantly in the future. As far as climate sensitivity is concerned, we're pretty certain of the uncertainty. The point Roe and Baker (2007) make is that throughout history our best estimate of climate sensitivity has been in the same ballpark, yet our uncertainty (the width of the distribution) has not significantly decreased. Arrhenius made adjustments for the positive feedback of water vapour in his 1906 paper. Roe and Baker (2007) is well cited. The IPCC says 'Most studies suggest a 5th percentile for climate sensitivity of 1°C or above.'

Skeptical Science

Soon, Willie

Spencer, Roy

Roy Spencer is a board member of the George C. Marshall Institute, which receives money from Exxon profits.

Tax and trade

Tax or trade? One solution is tax and trade. If we generalize both of them, the regulator allocates an initial fixed quantity of permits, but may engage in trading of the permits, buying them back or selling more. The regulator is then free to vary both emissions and the cost of compliance. If the regulator does not engage in trading, he has fixed the emissions. If he sells an unlimited number of permits at a fixed price, he has fixed the cost of compliance. In other words, we have the best of both worlds. The regulator can choose to what extent both emissions and cost of complinace vary. The four possible scenarios are outlined in the table below.

The regulator sells a fixed number of permits at a fixed price. The regulator sells a fixed number of permits at a variable price.
The regulator sells any number of permits at a fixed price. The regulator sells any number of permits at a variable price.

Tragedy of the commons

Human-induced climate change is a classic case of Hardin’s tragedy of the commons — the benefits of burning fossil fuels accrue to individuals, companies and nations, whilst the costs accrue to the planet as a whole. The tragedy of the commons is essentially a multi-player generalization of the prisoner's dilemma.


Trenberth (2009) was bemoaning the fact that our observation systems aren't able to consistently keep track of energy flow through the climate system in the short-term (see here).

Temperature Records

Global surface temperatures in 2010 tied with 2005 as the warmest on record. NASA GISS: Research News: NASA Research Finds 2010 Tied for Warmest Year on Record No less than 17 countries broke their national temperature records in 2010. The Guardian: World feeling the heat as 17 countries experience record temperatures Climate Central: Countries That Set New Record Highs in 2010




Likelihood TerminologyLikelihood of the occurrence/outcome
Virtually certain> 99% probability
Extremely likely> 95% probability
Very likely> 90% probability
Likely> 66% probability
More likely than not> 50% probability
About as likely as not33 to 66% probability
Unlikely< 33% probability
Very unlikely< 10% probability
Extremely unlikely< 5% probability
Exceptionally unlikely< 1% probability

All things being equal, 90% confidence intervals are simply wider apart if we are less certain of the underlying process, so the level of scientific understanding should already be implied in the confidence intervals. My preference would be to simply use probability for everything, but the IPCC are increasingly good at quantifying uncertainty. The greater uncertainty in aerosol forcing is made explicit by the width of the distribution, and this uncertainty is implied in the distribution of total radiative forcing.


Water vapour

The vast majority of scientists now agree that water vapour provides a strong and positive feedback.



Martin Sewell