In this post I want to take a step back and try to look at the scientific validity of climate change science.  It is important to determine whether the predictions are overstated and alarmist or whether they are alarming as a warning of what appears likely to happen.

To answer this question, we need to first look at the nature of science.  Personally I have not seen a definition of science that I find satisfactory, so I will attempt a description.  Others may disagree and they are more than welcome to make a different case.

A view of science

In my view, science is a way of looking at the physical realm based on a consistent theoretical framework.  Typically science is built on the core disciplines of physics, chemistry and mathematics.  Science includes a body of observations made and expressed within the terms of the theoretical framework.  It includes a body of published and, to a limited extent, unpublished information.  It includes collections, such as plant specimens in herbaria and fossil specimens in collections across the world.  It also includes photographic images.

With science being theoretical it can never be regarded as true.  Ironically, this is the strength of science and makes it reliable.  There is no place for authority given to individuals.  There are no expert witnesses within the scientific literature.  Every case must stand on its own merits, irrespective of the person presenting it.  (For clarity I would point out that this is apparently not necessarily the case in the public media and in politics, but I refer to the way scientists deal with each other.)

It is also important to consider the validity of consensus.  Some place a value on this, with the figure of 97% of scientists being in some sort of agreement.  In science, however, consensus is not a measure of any value.  Each case must stand on its own merits.  A scientist does not bow to the opinions of others; I am not aware of any case in which a scientist has written in a scientific paper that that something is beyond question because a certain person or group asserts it to be the case.  Even classification systems are open to question and review.

While there is no place for consensus, there is no place for marginalisation.  It is completely out of character to classify certain views as pseudo-science, for example.  If an argument is flawed, it is simply a matter of refuting the case.

Obviously not all science is reliable because scientist themselves disagree on many things.  Scientists are fallible human beings with limited knowledge.  Each has their own bias on particular issues.  Some science is hard to defend and is disregarded, but there are cases in which rejected views are adopted by others later.

From this perspective of science we can evaluate the validity of the science of climate change.  My understanding is that is it built on all of the disciplines that are relevant.  It takes into account such things as the thermodynamics of the gases in the atmosphere, the behaviour of the sun, history, geology.  This is what I would expect for anyone wanting to determine the drivers of climate change and their likely consequences.  It should make mathematical calculations to quantify the effect of the complete range of variables.  Using advanced computer models is the best way to provide a comprehensive consideration of all of the known variables.  From this perspective, the approach used by climate science is entirely appropriate.

I feel I need to say something about so-called scientific method.  The classical approach taught in schools is about objective data collection to test an hypothesis.  Nevertheless, life is not that simple.  In the real world it is almost impossible to isolate individual cause and effect behaviour.  It is possible to approach this in some controlled laboratory conditions and the disciplines of physics and chemistry rely on this approach.  In the real world beyond the laboratory there are inter-related variables.  Mathematics and statistics play an important part in processing the data.

In the end, science is often about quantifying certainly and uncertainty.  It is common to talk about 95% confidence levels, for example.  It is possible to quantify the significance of a relationship between causes and effects by finding controls.  This seems to have become the substance of modern scientific method.

Alarming of merely alarmist?

So, going back to the issue I raised at the beginning of this post.  This could be rephrased, “How can we determine if predictions of climate change are alarming or merely alarmist?”  I will attempt to answer this by considering two hypothetical situations.

The Merely Alarmist Scenario

Let us consider the possibility that climate science has severely overstated the likely risks.  In this scenario we could imagine that there is a systematic bias in the whole of the community.  Perhaps there is some unstated cause for pessimism.  There could be a bias in the peer review process that prevents dissenting views, as is commonly alleged.  There could equally be a bias in the provision of funding for research that achieves pre-conceived outcomes, as is also alleged.

This scenario could seem feasible except for the huge vested interest of the fossil fuel and other industries in maintaining the current dependence on hydrocarbon resources for the world’s energy needs.  There is a huge financial incentive to fund research that shows that the risks are overstated.  There is plenty of scope for independently funded research that could recognise faults in the theory or the data being collected.

It is claimed that those questioning the significance of anthropogenic (resulting from human activity) climate change are silenced or ignored.  However, I find this claim completely incredible in the context of the Internet and the vested interests involved; politicians and the media would exploit to the full potential any perceived weakness in the popular view of the science and attempt to do so currently.

If it were the case that climate science was merely being alarmist and overstating the risks, this would be easy to demonstrate.  It should be possible to document a basic flaw or flaws in the theoretical framework or systematic misrepresentation of observational data.  These are what I have sought as I have looked at the case made against significant effect of anthropogenic climate change over recent years.

In particular, I would expect there to be alternative computer models that correct the presumed errors that are commonly used.  These models would be hard to refute once they were generated.

The Alarming Scenario

Now let us consider the other extreme in which common concerns about anthropogenic climate change are actually a realistic assessment of the situation.

In this situation I would expect opposition from vested interest groups.  I would expect the opponents to present only exceptional data that supports a particular view without consideration of all of the data in the broader perspective.  I would expect their literature to be full of rants about freedom of expression and questioning the processes of peer review and allocation of grant funding.

In this scenario it should be possible to conduct studies of the behaviour of climate scientists and to understand the reasons for their bias.  For a group with 97% affirming agreement there would be plenty of potential for this sort of study.  I am not aware of any such study.

Most significantly, however, I would expect to see no flaws exposed in the theoretical approach and no evidence of systematic misrepresentation of observational data.  I would also expect there to be no computer models that provide a credible alternative projection of all of the data.

Responding to the science

My view is that the second scenario matches the current situation and the former does not.  Some may think that I have misrepresented the situation and they are more than welcome to point out their reasons for this conclusion.

I conclude that we are left in a situation in which the predictions of anthropogenic climate change are alarming.  There is still the possibility that all of the factors have not been considered.  However, this is the best that we have currently.  There is no known basis for concluding that the risks can be ignored.  It is time to respond rapidly and to reduce carbon emissions as fast as is humanly possible.

I would add that there are also many other benefits from a move away from hydrocarbons, so it is worth doing regardless of the threat of climate change.  There is air pollution, the pH of the oceans, loss of natural habitat, biodiversity and agricultural land from coal mining, the threat to the Great Barrier Reef, environmental disasters of oil spills as well as danger to workers involved in mining underground.