ISOS Miniproposal

April 2017

Martin Hänsel just came back from his research stay in Barcelona where he worked on his Miniproposal "Assessing temperature versus ocean acidification dynamics in an integrated model of environmental quality and the global economy". Here he gives an insight into his research.


During my time with Prof. Jeroen van den Bergh at the Institute of Environmental Science and Technology at the Universitat Autónoma de Barcelona the aim was to both study how to sensibly include economic effects of ocean acidification into state of the art integrated assessment models and further develop my professional scientific network, which is an essential part of a future career in academia.

We developed a static two-sector model of an economy, highly dependent on agriculture and fisheries, to study the interacting external effects of ocean acidification, global warming and eutrophication on socially optimal environmental policy. The integrated model captures that CO2 emissions not only contribute to global warming through an increase of the atmospheric temperature relative to the pre-industrial level but also cause ocean acidification. Global warming affects both sectors while ocean acidification influences fisheries. The model accounts for agriculture run-off of pesticides and fertilizers, which results in eutrophication of the ocean that negatively effects the productivity of fisheries. The utility of a representative consumer reflects both use and non-use values of agricultural and fishery resources by incorporating not only the consumption of their products but also a biodiversity value. The latter decreases in the three environmental damages. We derived optimal rules for taxes on CO2 emissions and agricultural run-off and showed how they depend on both isolated and interacting damage effects. In addition we derived a second-best rule for a tax on agricultural run-off of pesticides and fertilizers for the realistic case that an effective climate policy agreement is lacking. The results contribute to an understanding of the economics of ocean acidification in interaction with other important environmental stressors within economies that are particularly sensitive to environmental change.

Besides the production of scientific output the Miniproposal gave me the opportunity to further develop my scientific network. The Institute of Environmental Science and Technology offers a multidisciplinary research environment including ecologists, physicists and economists all working in one building. The organization of regular meetings with scientist outside the own discipline enabled an interesting and stimulating exchange of ideas. On the weekends Barcelona and Catalonia had a variety of things to offer including cultural sightseeing, language exchange, hiking and climbing.

I highly recommend doing a research stay outside the home working group during a doctorate, because it can change the way you perceive the world of science. Different working groups in different countries have very different habits in terms of working and science culture and thus, experiencing this variety can help you in finding out which culture best fits your own way of doing science.