Wirtschaftliche Auswirkungen einer alternativen Gestaltung der Klimapolitik

Keins der derzeit vorgeschlagenen Modelle für ein globales Klimaschutzabkommen sei stark genug, um die Erderwärmung unter dem Temperaturziel der EU von zwei Grad zu halten. Allerdings unterschieden sich die Modelle stark in Bezug auf ihre Konsequenzen für die Umwelt, die Wirtschaft und die verschiedenen Regionen der Erde, meinen Forscher der Fondazione Eni Enrico Mattei in einem neuen Arbeitsdokument für CESifo.

Warning of the dire consequences of climate change and the need for international cooperation, the October paper by Valentina Bosetti and other researchers seeks to compare various models put forward in literature setting out a structure for a global agreement on climate policy. It makes a quantitative comparison of eight different architectures by using a climate-energy-economy model specifically designed for the study of the socio-economic aspects of climate change.

The scientists used four criteria to evaluate the proposals. Environmental effectiveness was measured as estimated temperature change above pre-industrial levels in 2100 and economic efficiency as changes in Gross World Product (GWP) compared to the present situation. Political acceptability was assessed by changes in global and regional welfare compared to the status quo.

The research finds evidence of a „perfect trade-off between environmental effectiveness and economic efficiency and enforceability“. For example, including deforestation in a climate agreement would bring economic gains and more equal distribution of income between the world’s regions, improving enforceability in the process, it revealed. The paper cautions, however, that this is only the case for the most environmentally efficient models, which therefore entail GWP losses above 1%.

Moreover, the paper shows that all the proposed models improved global income distribution and implied greater global welfare, with the exception of the „autarkic coalition,“ which imposes a domestic carbon tax on all countries, including the developing world.

However, the researchers note that these welfare gains would accrue mainly to developing countries, which would consequently have to transfer resources to developed countries in order to reach a global deal, which is unlikely to prove politically acceptable.

While it is possible to distribute income more fairly, global economic losses are only negligible for policies with „intermediate stabilisation objectives“ for CO2 emissions, which may not make a sufficient environmental contribution, the paper states.

The authors conclude that the only policies which involve economic gain and are therefore likely candidates for a self-enforcing deal are those without any carbon constraints.