The efforts of developed economies to reduce their carbon dioxide (CO2) emissions by boosting the use of renewable energy sources and increasing energy efficiency are beginning to pay off. This is the result of a study conducted by an international team of researchers that includes scientists from Heidelberg. The group investigated the development of carbon emissions in 18 mostly European countries, among them the UK, France, Germany and the United States. The researchers found a sustained decline in carbon emissions in these countries over the period from 2005 to 2015. "This is proof that national climate policy is effective," says Jale Tosun of Heidelberg University’s Institute for Political Science. "But in order to limit global warming to well under two degrees, these efforts need to be broadened and intensified considerably."
Even though the decrease of CO2 emissions varies across the investigated countries, the researchers were able to identify three common factors driving the decline. One is the lessening relevance of fossil fuels, which are increasingly being replaced by renewable energy sources. In addition, improvements in energy efficiency mean that less energy is consumed overall. "In some countries such as Austria, the effect is due in large part to the greater share of renewables in energy generation, whereas the Netherlands, for instance, have been particularly successful in reducing energy demand. In Germany, both factors are equally significant," explains Prof. Tosun.
The third factor, according to the Heidelberg scientist, is strong legislation. The study shows that ambitious political strategies aimed at promoting renewable energy sources and increasing energy efficiency, and the underlying framework policies, have made a noticeable contribution to reducing carbon emissions. "What is striking is that the countries with the most significant decline in CO2 emissions are also the ones with the highest number of energyand climate-related policies. This is particularly true for Nordic states like Denmark and Sweden", emphasises Jale Tosun, who conducts comparative analyses of environmental, energy, climate change and sustainability legislation across several countries at the Institute for Political Science, and collected the data on climate policy for the study.
The countries reviewed in the study account for 28 per cent of worldwide CO2 emissions. Between 2005 and 2015 they showed a decrease of carbon emissions by an average of 2.4 per cent per year - although this was due in part to reduced energy demand that accompanied the economic slowdown during the global financial crisis of 2008/2009. "Even though our findings for these 18 countries were compared to a control group and can therefore be termed ’robust’, they cannot be applied to countries with rising CO2 emissions and slow economic growth, such as Japan, or countries with rising emissions and fast growth like China. They only pertain to countries in which carbon emissions have already reached their peak."
The study was conducted under the direction of the Tyndall Centre for Climate Change Research at the University of East Anglia in Norwich (UK), as part of the network "Innovations in Climate Governance: Sources, Patterns and Effects" (INOGOV), which coordinates projects in the fields of climate policy and policy innovation. INOGOV is an initiative of COST - the European Cooperation in Science and Technology - which promotes cooperation in scientific and technical research across Europe. The findings were published in "Nature Climate Change".