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Published: 24.05.2007, 06:00
Modified: 24.05.2007, 06:17
ETH Zurich researcher on the 4th UNO Climate Report
More uncomfortable facts

The Fourth UNO Climate Report provides new facts about the future of our world. Even the main author of the chapter “Ecosystems: Properties, goods and services”, Andreas Fischlin from the Terrestrial Ecosystems Group of ETH Zurich, is shocked by the discoveries. However, he thinks that is no reason to despair: “It’s already late, but not yet too late!”

Peter Rüegg

The fourth report on global climate change by the UNO’s Intergovernmental Panel on Climate Change (IPCC) does not make pleasant reading and is even gloomier than its predecessor in 2001. The climate is changing and is doing so at breakneck speed. It is clearly apparent to ETH Zurich researcher Andreas Fischlin from the Institute of Integrative Biology, the author with chief responsibility for the fourth chapter (1) by the IPCC’s Work Group II, that human beings are producing too much CO2 and the Earth’s ecosystems will change greatly in the foreseeable future.

There has been an average global temperature rise of 0.75 degrees Celsius from the start of industrialisation to 2005, and as much as 1.6C in Switzerland. A temperature rise of 2C would already be enough to cause desertification in the valley regions of the Valais canton. Trees can no longer flourish in such a climate. Fischlin draws attention to the pine-tree deaths already observed in the Valais and possibly associated with climate change. At most they could be replaced some day by dwarf downy oaks – if at all.

The end of the road for the edelweiss?

A temperature rise of two to three degrees compared to the pre-industrial climate would endanger many higher plants and animals throughout the world, and would probably also cause problems for the living things in the Alps. For example the rock ptarmigan or edelweiss or even up to 30 percent of the remaining indigenous flora and fauna might be doomed to die.

Fischlin stresses one aspect of the new report in particular: if the current rate of greenhouse gas emissions persists, the climate change by the end of the century will exceed the resilience of many ecosystems. This is because several factors interact in a hitherto unknown way: there would be a fatal combination of climate change and associated disturbances such as flooding, drought or insect infestation together with changes in land use, environmental pollution or over-exploitation.

An over-stretched spring

In fact the resilience of ecosystems is comparable to a spring. If an ecosystem is “deflected”, for example by a drought, it can return to its original state without suffering any damage if “normal” conditions are soon re-established after the extreme event and the deflection remains within certain limits. However, if the deflection exceeds this magnitude, namely that of the resilience, the spring permanently loses its ability to return to its original shape. The researchers describe permanent damage of this kind for numerous ecosystems even within the present century if the current trend continues unchecked.

Oceans increasingly acid

Another new and important revelation in the Climate Report is the acidification of the oceans. Up to now only a few scientists were working on this phenomenon resulting from the atmosphere’s rising CO2 content, although the basic chemistry of the bicarbonate system is very well understood. Only in recent years have a very few scientific papers been published on this subject.

However, they clearly show that globally the oceans have become more acidic by 0.1 pH since industrialisation. Simulations show that the pH could drop by 0.6 by the year 2250. By 2100 the pH could fall to a value lower than at any time in the last 20 million years. Fischlin says “That would be fatal for crustaceans such as mussels, marine snails or squid as well as for reef-building corals.” However, he says the topic urgently needs further work before researchers can make any definitive statements on the subject.

In any event the results of climate research in recent years confirm that there is at least a 90 percent probability that mankind is responsible for the climate changes observed up to now. Based on the public response, the researcher thinks he can conclude that “This result seems to be a kind of breakthrough for the population.”

The biosphere becomes a CO2 source

In addition, climate change could continue to accelerate even without any direct human input. The reason is that ecosystems on land currently act as sinks because at a high turnover they currently absorb in total more CO2 than they emit. However that could change decisively as early as 2030 because the latest model calculations show that this absorption capacity will then go beyond its peak and will start to drop. Together with current trends in the changes in land use, it is expected that there will even be a net release of CO2 after that date, and the biosphere will become a source of CO2. There would be an additional cranking up of climate change firstly through the weakening of CO2 absorption and of course later by the source effect. This effect could contribute up to an additional 1.2C to global warming.


A window into the future for diving enthusiasts: coral bleaching has destroyed reef-building molluscs in the Great Barrier Reef off the east coast of Australia. (Photo: Ove Hoegh-Guldberg, University of Queensland, Australia). large

Moreover, a similar feedback effect from the sea is also to be feared. In the same period of time the oceans will approach CO2 saturation, which would mean a noticeable reduction in the previous sink effect. With unchecked emission of greenhouse gases, this would lead to a marked acceleration of climate change.

A Herculean task for ETH Zurich researchers

Andreas Fischlin took more than 3000 references into account for the fourth main chapter, and says “The literature on the subject has really exploded since the last report in 2001.” However, only papers that are new since that time have been included. The main aim of the Report is to present all the differing or new insights. Important confirmations of previous discoveries are the only additional material. The Report had to undergo four rounds of reviews and hundreds of specialist consultants throughout the world were invited to respond. The revision yielded more than 4000 comments, each of which had to be individually answered in writing, justified and made publicly accessible. This enables any possible critics to follow how the final version of the report was produced. As he says himself, for Fischlin it was altogether an enormous task begun more than four years ago, requiring three years of work to write and having brought him to the brink of exhaustion. However, the ETH Zurich researcher considers it an honour to have been the principal author of a chapter..

A happy medium for politicians

The IPCC Report strives for a scientific consensus rather than being based on extreme scenarios. Preference is given to using data and scientific knowledge that is robust and among the most reliable. Fischlin stresses “That’s why the political world should take the report seriously.” He and his co-authors spent a total of six months just on the summary for decision-makers(2). They thought long and hard about every sentence. Andreas Fischlin says he was himself greatly shocked and dismayed by the report’s results and insights, and they put him in a thoughtful mood. The ETH Zurich researcher says “If the present emissions trends and global changes continue – i.e. no climate protection – it is highly probable that the forecasts that have been made will come true. However, I hope we will still be able to reduce the emissions.”

Model calculations show that an 80 percent global reduction in CO2 emissions by 2100 is necessary to avoid serious adverse consequences of the kind described in the Report. However, for many industrialised nations with historically comparatively large greenhouse gas emissions, which includes Switzerland, this need for reduction is even larger and may be as much as 90%. For example there are even demands requiring a reduction by 90% as soon as 2050, as Al Gore called for recently during a hearing before the American Senate.

A large energy potential in the sea

This could be achieved through better energy efficiency, mainly in the case of new buildings, more economical automobiles and the use of alternative energy sources, for example thermal ocean power stations, OTEC – Ocean Thermal Energy Conversion (3), which are often overlooked and which exploit the temperature difference between the deep and surface water to generate electricity and produce hydrogen as an energy carrier. In the context of the Climate Convention(4), practically all governments have committed themselves to putting climate protection into practice. In this context the finger is often pointed at the USA because it has not ratified the Kyoto Protocol of the Climate Convention. However, it is noteworthy in this connection that the US American delegates participated constructively in accepting the summary for politicians. However, as far as Swiss climate policy is concerned, in Fischlin’s opinion important time was lost in the past two years through hesitant decision-making in connection with CO2 emissions, thus probably squandering big opportunities for Swiss industry. The Federal Council is now planning to finalise its long-term climate policy in the autumn, especially for the period following the present Kyoto Protocol after 2012. The committed researcher’s demand is that “It must use this to point the way to a future worth living, especially for our children and grandchildren.”

(1) Fischlin, A. & Midgley, G.F., 2007. Ecosystems, their properties, goods and services. In: Parry, M., Canziani, O. & Palutikof, J. (eds.), Climate change 2007 - Impacts, adaptation and vulnerability. Contribution of Working Group II to the Assessment Report Four of the Intergovernmental Panel of Climate Change (IPCC). Cambridge University Press, Cambridge, UK, p. 102 (in prep.).
(2) Summary for politicians:
(3) (3) Information about OTEC: bzw.
(4) United Nations Framework Convention on Climate Change:

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