Science and Technology CommitteeWritten evidence submitted by Dr Richard Lawson (CLC0063)

Written evidence submitted by Dr Richard Lawson, a retired General Practitioner of medicine and Green Party activist (one of the first Greens to be elected to a local authority), author of Bills of Health (Radcliffe 1996), on the impact of political and economic conditions on NHS spending. I have been debating climate science with climate sceptics on the web over the past four years.


The public is turned off by the complex nature of the climate debate, and the seemingly irreconcilable differences of “experts”.

However, a little-recognised consensus has emerged between both sides, namely:

The Greenhouse Effect exists, and CO2 is a greenhouse gas

Doubling CO2 levels will produce a global temperature increase (eventually, when equilibrium is re-established) of about 1.2°C.

Climate Sensitivity (CS) means that this increase will be amplified.

Mainstream climatologists hold that CS means that a doubling of CO2 will cause an eventual temperature of 2–4°.

“Lukewarmer” sceptics believe that the eventual temperature lies between 1°C and 2°C.

There is therefore a common figure of 2°C, and it will be productive to discuss whether this figure would be tolerable for humanity or not.

A Polarised Debate

It is well known that the debate over anthropogenic climate change is deeply polarised. At the extreme of the side that rejects the scientific consensus are a group who are implacably opposed to accepting any part of mainstream climate science. Every point of science, whether it be the greenhouse effect, the physics of CO2, or the possibility that we could decarbonise the economy, is vehemently contested, and no coherent case is put forward for an integrated view of the planet’s energy budget. These “sceptics” believe that climatology has been almost universally corrupted by a political conspiracy whose aim is to raise taxes for the sake of raising taxes, destroy Western capitalism and usher in a totalitarian New World Order.

It is pointless to debate with these people, just as it is pointless to debate with a creationist.

However, over the past few years there has emerged a group of climate sceptics called Lukewarmers. They do accept a large part of the scientific basis of climatology, but they believe that the effect of greenhouse gas emissions will be minor rather than catastrophic. Lukewarmers have penetrated into the political establishment in the UK, and occupy more than one position of authority in the present Government.

A Consensus Figure

Lukewarmers accept that the Greenhouse Effect exists, and that CO2 is a greenhouse gas. They accept that a doubling of CO2 will produce a global temperature increase (eventually, when equilibrium is re-established) in the vicinity of 1°C. They accept that Climate Sensitivity (CS) means that this increase will be amplified to some extent, but believe that the eventual equilibrium temperature for a doubling will lie between 1° and 2°C.

Mainstream climatologists on the other hand believe that CS means that a doubling of CO2 will cause an eventual temperature rise of 2–4°.

There is therefore a common temperature increase of two degrees Centigrade which both sides of the debate agree is a possible outcome. The figure lies at the top end of the range of that accepted by sceptics, and at the lowest end of the range accepted by climatologists, but nevertheless, it is accepted as possible by both sides.

How Consensus Modifies the Debate

Major changes flow from the insight that 2 degrees is accepted by both sides. The debate becomes simplified and comprehensible to the person of average intelligence. Instead of ranging across the whole immensely complex field of earth systems, it focuses on these three major points:

1.Scientific evidence on climate sensitivity.

2.The nature of feedback mechanisms, their sense and magnitude.

3.The changes in biodiversity, climate, weather, economics and politics that might reasonably be expected as a result of an increase of 2°C over pre-industrial levels.

Furthermore, in terms of scientific method, a classic Popperian refutation becomes possible. The lukewarmers are putting forward a testable hypothesis, that anthropogenic greenhouse gases have a minor effect. This hypothesis can be tested, both in terms of whether their evidence for low sensitivity is robust, and also whether their estimates of the effects of a 2°C temperature rise, which they accept is possible, can in fact be classed as trivial and tolerable.

The emerging scientific discipline of “Attribution” becomes relevant here. If it is possible to attribute extreme weather events to anthropogenic changes at the present level of warming (0.7°C), it becomes very clear that an increase of 2°C could not be regarded as trivial.

This testability of the lukewarmers sceptics’ case gives us the opportunity to conclude the first phase of the climate debate, regarding the seriousness of the effects of CO2, so that we can move forward to determining and implementing the best policies for decarbonising the global economy.


1. The STC should suggest that the Government’s Chief Scientist should prepare a report reviewing the evidence regarding CS, and another reviewing the impact of a 2°C temperature rise.

2. The Science and Technology Committee should put the points made here about the game-changing nature of the consensus CS figure of 2°C into its report.

3. The STC should persuade DECC and other relevant sections of Government to take on board the line of reasoning presented in this paper.

September 2013

Prepared 1st April 2014