Mr. Peter, in your book contribution (1) you describe how the chemist Sherwood Rowland used his scientific knowledge about the destruction of the ozone layer to motivate politicians and the public to take action. Are there similar players in the climate debate today?

The Committee of the Intergovernmental Panel on Climate Change (IPCC) (2) is in the driving seat in the political process about climate debate, and no longer individual scientists. I think public catalysts of this kind are needed to generate majority support for long-term precautions against environmental hazards. If Rowland and a few other colleagues had not persevered at that time in drawing attention to the possible consequences of ozone destruction and had not vigorously urged countermeasures, CFCs would certainly not have been banned until considerably later.

The summary of the Fourth IPCC Report was published early in April. It leaves practically no more room for doubt that climate change is caused by humans. Nevertheless critics still dispute the need for immediate action, for example Bjørn Lomborg whom you quote at the start of your book contribution. What is your assessment of the current position?

More specific data was available for the fourth IPCC report than ever before. This enabled the report’s authors to clear away many past uncertainties. The observations of glaciers, oceans and climate changes on all continents are clear evidence of climate warming. The theory that humans are the cause of these changes is also further strengthened compared to the previous report in 2001. As a scientist I cannot shut my eyes to these results. In spite of further uncertainties in the predictions, we must act as quickly as possible.

In your contribution you talk about the ethical responsibility of scientists to the public. Where does this lie?

A scientist has two important functions in this context: firstly he/she must publicise his/her knowledge in the scientific community, thus exposing new results to critical scrutiny by experts. Secondly, however, he/she must also organise and evaluate the results for a wider public. Since we are working with uncertainties and probabilities in relation to possible climate change scenarios, this organisation and evaluation of the data and relationships confronts scientists with the great challenge of finding a clearly understandable language without at the same time exaggerating or making unacceptable simplifications.

What is noticeable in the present climate debate is that it is popular science opinion leaders like Al Gore or Bjørn Lomborg with their books and personal appearances, and not the technical experts, who are creating the biggest response among the public. Isn’t that a problem?

Firstly I don’t think the Fourth IPCC Report is receiving less media coverage and response among the general public than Al Gore’s film. Secondly I have seen Al Gore’s film and was astonished at the depth in which it analyses the material. I believe that a film of this kind achieves an definitely beneficial impact by raising public awareness of urgent problems. As far as climate sceptics like Lomborg are concerned, I think climate researchers have no option but to grapple with these opinions as well. At our Institute we already discussed inviting Lomborg to a symposium, but some colleagues firmly rejected it as pointing in the wrong direction.

Some daily newspapers write about “climate shock” and CO2 as a “killer gas”, and other media talk about the “horror scenarios” of your ETH Zurich colleague Andreas Fischlin. What is your general assessment of the media reporting of climate change?

As I said already: the scientific knowledge currently available indicates clearly that climate change has anthropogenic causes. Considering the seriousness of the position and the possible consequences, I regard the present reporting as appropriate to the subject, insofar as it draws attention to the critical situation.

Thomas Peter, Professor for Atmospheric Chemistry: “Without international solidarity we will be unable to take effective action against climate change.”

In your opinion, what are the fundamental differences between the ozone debate in the eighties and the current discussion of climate change?

Climate change is perceived to a much greater extent via its economic dimension than was the CFC problem. In a case study we compared newspaper reports about the ozone hole in the eighties with the present newspaper reports of climate change. What this reveals is that the reporting of the ozone hole gave very much greater weight to health aspects than is the case for climate change today. The topics of skin cancer and the ozone hole were closely linked at that time.

Why is that?

Fossil fuels are society’s energy backbone nowadays, which leads to worries about survival. People ask questions like “What will happen when we are only allowed to drive cars on three days a week?” or “Will I still be able to heat my home with mineral oil next winter?” So the fear is about the consequences of politically imposed measures and no longer the direct impact on one’s own health.

Does the climate debate also raise new ethical questions?

Yes. Heated debates are already taking place in the geo-engineering area as to whether climate change can be mitigated by specific geological interventions. Does that mean trying to combat the present climate change with a consciously controlled “man-made” climate? Of course critics object that it is not for humans to determine the climate. On the other hand supporters claim it would be negligent not to act, since the consequences of “inactivity” could be much more serious than the risks of an intervention itself. As you see, it involves a classical dilemma because we can only risk a single experiment with Planet Earth.

What can we learn for the future from the ozone debate?

We saw at that time that although the ozone problem was basically already known about in the seventies, politicians did not adopt concrete measures in the shape of the 1987 Montreal Protocol (3) and follow-up agreements until after the ozone hole was discovered in 1985. This recognised the problem at a global level and brought the international communities together in a joint fight against chlorinated and brominated chemicals. The potential hazard from CO2 has also been recognised internationally in the meantime, and the present IPCC Report contributed considerably to that. In spite of the Kyoto Protocol, there is so far still no unanimity in formulating measures. Without international solidarity, which must no longer be shaped primarily by individual national interests but by global ones, we will be unable to take effective action against climate change.

Thomas Peter has been a full Professor for Atmospheric Chemistry at the Institute for Atmospheric and Climate Science of ETH Zurich since the start of 1999.