Science, Climate Change and Integrity

Statement from Professor Keith A Hunter FNZIC, FRSNZ, Vice-President – Physical Sciences, Mathematics, Engineering and Technology, Royal Society of New Zealand.

Summary of Statement

The science of climate change has been the subject of recent harsh criticisms in the popular media, with attacks on the integrity and professionalism of scientists. There is fault on both sides of the equation, with the need for absolute transparency of information being the key issue. Adopting a more transparent approach to the dissemination of information will lead to a clearer picture of the facts.

Science has not “proved” beyond all reasonable doubt that human activities are changing the climate. But it has clearly shown that there are multiple lines of evidence all pointing in the same direction, and this view is supported by theories that are well-founded in fundamental sciences like physics.

Commonsense and prudence says we should respond and not ignore the evidence about climate change as it currently stands. The risks of doing nothing are too great.

The mitigation measures suggested for climate change (reduced use of carbon-based fuels, more renewable energy sources, carbon capture and storage, less use of nitrogen-based fertilizers) are all part of a portfolio of approaches that are needed to produce a more sustainable world.

Full Statement

In recent months, the science of climate change has been subject to harsh criticisms in the popular media, with even more critical comments circulating in the anonymous medium of the internet.

This commentary has quickly escalated into attacks on the integrity and professionalism of scientists themselves, usually in circumstances where they are unable to defend themselves, or unwilling to make themselves the target of personal abuse. Some prominent climate scientists have even received threats of violence against them or their families.

This situation is to be deplored because it carries all the hallmarks of our pre-scientific past when political, religious and military power dictated what was deemed to be the truth, and is the very antithesis of a modern rational society applying accepted scientific methods. It is not necessary to belabour the human atrocities that such times engendered.

Faults on both sides of the ledger

That is not to say there is no fault on the part of the climate scientists, and their scientific institutions. The emails illegally hacked from the UEA Climate Research Unit mail server reveal the bitter frustration felt by some prominent climate researchers with the small but very vocal community of people who dispute their findings. However, this frustration does not justify appearing to conspire against other scientists who are genuinely sceptical and seek to publish their views in scientific journals.

This is a timely lesson for all scientists, because while we place great faith in the peer review process to weed out ideas that are wrong, peer review is not perfect and can be abused by both sides.

The emails also show that some climate scientists have become frustrated with repeated calls for the disclosure of climate information from parties they consider to have ulterior motives. Their concern is that the critics seek to pounce on minor errors, or examples of a lack of clarity, which they can then use to further frustrate the climate scientists and create more doubt in the minds of the general public about the meaning and value of the science itself. In the end it is not important what the motives of the critics are, even if self-declared.

Science is a rational endeavour that is based on logical and critical analysis of scientific theories in the light of actual evidence. It follows that scientific information, including a transparent description of how the data has been processed and tested against hypotheses, must be publically available, especially when it has been publicly funded and relates to such important issues as climate change. Regrettably, many of our scientific institutions have not lived up to this ideal, or at the very least have failed to keep up with the huge changes in information technology that have taken place over the last decade that have radically changed the nature of public comment.

Adopting a more transparent approach

However, lessons can be learned from “Climategate”. If the intensity of the personal attacks on climate scientists over recent months are to have any positive effect, it will be the adoption of a more transparent approach to the dissemination of information. In this regard, the Royal Society of New Zealand intends to play its part by developing a Code of Practice for Public Dissemination of Information that it hopes will assist the various New Zealand science organisations in improving their practices.

At the same time, of course, it is only fair to expect the critics of the mainstream scientific views on climate change (and other contentious areas of science) to adopt an equally transparent approach with their own information, and with their own use and re-analysis of data entrusted to the public domain. They should also subject their findings to rigorous peer review. Opinion, however forthrightly expressed, will not change the laws of basic science.

Much has been said in the media, especially since the publication of the IPCC 4th Assessment Report in 2007, that “the science of climate change is settled”. This is a poor description of the state of the evidence. Science is never settled, but is always subject to refinement as new ideas and alternative evidence emerge. All practising research scientists know this. Many of the critics of the idea of anthropogenic global warming (AGW) repeatedly demand to be presented with the conclusive scientific evidence that the AGW theory is correct. In other words, they want us to conduct the “definitive experiment”.

Philosophers (whose deliberations about the nature of the universe pre-date modern science by at least 2000 years) know clearly that a scientific theory cannot ever be proven (or disproven), even by scientific facts. This is a logical impossibility. Instead, scientific evidence (experiments) merely allows good theories to grow stronger and bad ones to become less well-regarded.

The evidence for global warming caused by humans comes from many sources

What does this mean in the context of the current climate science debate? In my opinion, the controversy over whether or not it is acceptable to adjust temperature readings from different geographical locations to take account of locational differences (a standard practice in meteorology), or whether this is a fraudulent way to “manufacture” a non-existent warming trend, is not by itself sufficient to invalidate the entire findings of IPCC.

The evidence pointing towards AGW comes from multiple independent lines of argument, each pointing in the same direction. It is not the intention of this article to labour this point, but a few examples follow:

  • It is a plain fact that human activities have significantly increased the concentrations of greenhouse active gases in the atmosphere, particularly since the mid-20th century.
  • The amount of extra carbon accumulated in the ocean and the atmosphere matches the known quantity emitted by the combustion of fossil fuels.
  • It is simple physics that these extra gas concentrations will trap an increased amount of outgoing solar radiation reflected off the Earth’s surface, of the order of 1.5 watts per square metre of the Earth’s surface.
  • It is also clear that the oceans absorb about 85% of the excess heat resulting from this radiative forcing by greenhouse gases (as well as about 40% of the carbon dioxide). Detailed measurements of the changes in oceanic heat content, and the temperature rise that accompanies this, agree quantitatively with the predicted radiative forcing.
  • Furthermore, satellite altimetry shows clearly that the sea level has risen by the amount expected as a result of the warming-induced thermal expansion of the ocean.
  • Finally, in recent years it has become clear that salinity increases in the tropical ocean from enhanced water evaporation, and parallel decreases in salinity at higher latitudes as the enhanced water vapour condenses again, consistent with the higher heat content of the tropical ocean and with observed changes in the atmosphere.

From a philosophical point of view, none of these lines of evidence “proves” the theory of AGW. However, by the same token, Joseph Lister did not “prove” that antiseptic surgery practices prevent sepsis; he only demonstrated that their use gave rise to vastly fewer deaths from post-surgery sepsis. The adoption of these practices came about not because a theory was “proved”, but because medical practitioners had the common sense to realize that he was very likely right. A more fundamental understanding of his ideas came about only when the microbial nature of disease was fully revealed.

This “precautionary principle” applies equally to climate change. Science has not “proved” beyond all reasonable doubt that human activities are changing the climate, but it has clearly shown that there are multiple lines of evidence all pointing in the same direction, and that this view is supported by theories that are well-founded in fundamental sciences like physics.

Commonsense says we should respond

How we, as a society, respond to this situation is not in the realm of science but in the realm of commonsense.

Future climate change may not be as severe as predicted, or it may be worse, and there is even a very small chance it may not amount to anything much at all. The question is, what are the risks and what are the costs? Most of us are inherently prudent when it comes to dealing with this balancing act.

When we get into a motor vehicle, very few of us intend to have an accident, and we are unable to predict with certainty whether one will happen on a given day. Indeed, the overall statistics show that motor accidents are not very common at all in relation to time spent driving. Yet most of us accept motor insurance, driving rules, speed limits, alcohol limits, driving education, warrants of fitness etc as prudent ways to mitigate the harmful effects of motor accidents because they can be very severe if they happen. We need to inject the same kind of commonsense prudence into what we do about climate change, which is largely what the New Zealand government has indeed done.

Time will tell who is right or wrong

Climate science has delivered a stern message of warning that is hugely relevant to how we will live over the coming decades, and the world that our grandchildren will inherit. Only history will show whether the climate scientists are right or wrong. My personal prediction is that if they are right, those who promote doubt and dissension, and thus inaction, will be vilified for their influence. If they are wrong, nobody will care much because the efforts made to mitigate the now-perceived problems will lead to a better world in any event.

Science’s warnings about other issues

Finally, I would like to point out that climate change is only one consequence of human activity that we should be deeply concerned about, and about which science has already delivered stern warnings.

As well as being implicated in warming the climate, carbon dioxide from fossil fuel combustion is altering the chemical composition of the oceans (ocean acidification). The effects of this process on marine organisms are complex and varied, and are currently the focus of intense research.

The geological record shows that natural acidification events in the Earth’s past associated with release of methane deposits, were accompanied by massive extinctions of marine organisms and large changes in ecological systems. The record shows that many thousands of years were required for those ecosystems to recover. The only way to combat this potential threat is to reduce the consumption of carbon-based fossil fuels.

Once again, the risks of doing nothing are too great.

Other areas of concern are the rapidly growing problems of adequate and sufficient water supply, and their contamination by chemicals and nutrients, a dwindling supply of oil and gas, rising populations, shifting political balances as a result of these energy demands, food production, loss of natural habitats and environmental degradation. This is an extremely poor report card for the human race.

The mitigation measures suggested for climate change (reduced use of carbon-based fuels, more renewable energy sources, carbon capture and storage, less use of nitrogen-based fertilizers) are all part of a portfolio of approaches that are needed to produce a more sustainable world.

The debates will continue, both about the science and what our responses will be as a society. Debate, and scepticism are healthy and to be encouraged, as is transparency of information. However, vicious personal attacks on the integrity of experienced scientists, and indeed their critics, serve only to detract from the real issues and are out of place in a rational society.