Climate-engineering: sleutelen aan klimaat nog niet aan de orde

16 Jul

Een Europese samenwerking op het gebied van klimaat-engineering EuTRACE  heeft haar eindrapport uitgebracht met als titel “Removing Greenhouse Gases from the Atmosphere and Reflecting Sunlight away from Earth”. Partners in het door Europa gefinancierde project waren instituten uit Duitsland, UK, Noorwegen, Frankrijk en Oostenrijk.

Dit zijn de belangrijkste conclusies:

Doelgerichte interventies in het klimaat (“klimaat-engineering” of “geo-engineering”) zijn geen vervanging voor de vermindering van de uitstoot van kooldioxide en de implementatie van adaptatiestrategieën voor de negatieve gevolgen van de klimaatverandering. Of het mogelijk is om één van de voorgestelde geo-engineeringtechnieken zo ver te ontwikkelen , en vervolgens zo’n maatregel op te schalen tot een niveau , dat de klimaatverandering merkbaar zou vertragen, is nog onduidelijk. Het is niet alleen een kwestie van tekortschieten van de  techniek, het energieverbruik en ook de maatschappelijke kant, het draagvlak voor majeure ingrepen in het klimaat, en de stand van de regelgeving spelen een remmende rol, aldus EuTRACE. Men verwacht de eerste tientallen jaren nog geen resultaat.

Uit een Engelse samenvatting:

The report … illustrates many of the challenges and concerns associated with climate engineering, focusing especially on three example techniques: bio-energy with carbon capture and storage (BECCS), ocean iron fertilisation (OIF), and stratospheric aerosol injection (SAI). Research on climate engineering has thus far been limited, mostly based on climate models and small-scale field trials. This research has not only shown the potentials of greenhouse gas removal and possibly of albedo modification for partially counteracting climate change over the long term, but has also shown that there are many problems and challenges that would be associated with their implementation, not only in terms of costs, technologies and environmental impacts, but also in terms of societal impacts and the development of regulation and governance.

One scientific challenge that generally applies to techniques for both greenhouse gas removal and albedo modification is understanding how their application could result in numerous harmful impacts on ecosystems, many of which are presently uncertain or unknown. Many other scientific and technical challenges are more specific to one of the two broad categories:

Greenhouse gas removal techniques face numerous scientific and technical challenges,
including:
– determining whether the techniques could be scaled up from current prototypes, and what the costs of this might be;
– determining the constraints imposed by various technique-dependent factors, such as available biomass;
– developing the very large-scale infrastructures and energy inputs, along with the accompanying financial and legal structures, that most of the proposed techniques would require; based on existing knowledge and experience, this could take many decades before any technique could have a significant impact on global CO2 concentrations.

Proposals for cooling the Earth’s surface by increasing the albedo – the fraction of solar radiation that is reflected back to space – also face extensive scientific and technical challenges, so that it is unclear whether any of the proposed techniques would ever be technically feasible. Some of the challenges that would first need to be addressed include:
– very large and costly infrastructures that land-based techniques would require;
– delivery mechanisms for techniques based on injection of aerosol particles into the atmosphere, including delivery vessels (e.g., high-flying aircraft or tethered
balloons) and associated nozzle technologies;
– a much deeper understanding of the underlying physical processes, such as the microphysics of particles and clouds, as well as how modification of these would affect the climate on a global and regional basis.

Societal context and development of governance and regulation
A major part of the EuTRACE assessment report was to highlight the possible effects of various climate interventions on human security, conflict risks and societal stability. At present, no existing international treaty body is in a position to broadly regulate greenhouse gas removal, albedo modification, or climate engineering in its entirety. The EuTRACE assessment therefore stresses the value of engaging the public into the discussion about climate engineering. It also suggests that EU member states could consider pursuing an agreement on a common position on various techniques or general aspects of climate engineering, especially if such an agreement could be made consistent with the high degree of importance that EU primary law places on environmental protection.

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