According to the study, Australia, Indonesia and the United States offer the greatest potential for carbon storage with their coastal ecosystems. The team also calculated which countries benefit the most from coastal CO2 worldwide adoption. The different ways in which countries are affected by climate change are quantified using the so-called social costs of carbon.
“If we take into account the differences in the marginal climate damage that occurs in each country, we find that Australia and Indonesia are clearly the biggest donors in terms of global avoided climate damage from CO. coastal.2 because they themselves derive relatively little benefit from the high storage potential of their coasts, ”explains Wilfried Rickels, who heads the Global Commons and Climate Policy Research Center at the Kiel Institute. “The United States, on the other hand, also stores a lot of carbon in its coastal ecosystems, but at the same time benefits the most from the natural sinks behind India and China. In monetary terms, the three countries achieve annual welfare gains of approximately US $ 26.4 billion (India), US $ 16.6 billion (China) and US $ 14.7 billion (United States). United) thanks to global coastal ecosystems and the resulting lower climate impact costs.
The basis of monetary calculations is the so-called social cost of carbon, which makes it possible to assess the contribution of coastal carbon absorption in the concept of “inclusive wealth”. “Inclusive wealth” is defined as the totality of all stocks of natural and anthropogenic capital, valued with so-called shadow prices, ie contributions to social well-being. Among other factors, the absolute scarcity of resources plays an important role for shadow prices. Atmospheric CO2 has a negative impact on well-being mainly because of climate change. However, countries are affected differently by climate change and therefore country-specific shadow prices are used in the study.
The analysis does not include other carbon sinks or emissions from energy and industry. When carbon emissions from energy and industry are also taken into account, only Guinea-Bissau, Belize, Vanuatu, Sierra Leone, Solomon Islands, Guinea, Comoros, Samoa, Madagascar and Papua New Guinea make a net positive contribution through their coastal ecosystems, as they store more CO2 in coastal ecosystems than they emit altogether.
The study also highlights that carbon storage is only a small part of the positive impacts of coastal ecosystems for humans. “Coastal ecosystems are an essential component of marine ecosystems and are therefore particularly important for marine biodiversity and for fisheries. At the same time, they help protect against floods and coasts and are therefore important for adaptation to climate change, ”emphasizes Martin Quaas, who heads the research group on the economics of biodiversity at iDiv and UL.
Whatever the case, the emphasis is still very strong today on afforestation of land with regard to the challenges of achieving the Paris climate objectives. “Marine CO2 absorption as well as its improvement needs more attention in the debate on net greenhouse gas emissions and net CO2 emissions2 emission targets, “Rickels points out. In particular, a possible weakening of marine carbon sinks would require even greater carbon dioxide mitigation and removal efforts.” The coasts, with their many different user groups as well as possible conflicts of use, have a role to play here. “
The natural capital approach used in the study is suitable to assess the resulting redistribution of CO2 emissions and CO2 sinks, which, unlike existing market-based assessments, is not influenced by the stringency of the underlying climate policy. The researchers plan to explore this question in further studies.