Researchers warn that the costs caused by the impacts of climate change are leaving out a central part of the problem: the seas and oceans.
Led by the Scripps Institution of Oceanography, of the University of California in San Diego, the work is described by its authors as the first to integrate climate damages to marine realms into the calculation of the social cost of carbon. This is a measure used to estimate the sum of all costs – environmental, economic and social – caused by the impacts of carbon dioxide emissions to the atmosphere. Essentially, it converts the impacts of climate change on people’s lives into measurable costs.
However, the focus has been almost exclusively on land, hiding a fundamental part of these costs. In a paper published in the journal ‘Nature Climate Change, scientists reveal that when the blue dimension, until now largely ignored, is considered, the global cost of carbon dioxide emissions to society nearly doubles.
This disregard, they say, occurs even at a time when the degradation of coral reefs and their ecosystems, losses in fisheries due to changing environmental conditions, and damages to coastal infrastructure resulting from extreme events are well documented.
Bernardo Bastien Olvera, the first author of the study, says that if a “price tag” is not placed on the damages that climate change is causing to the oceans, these impacts will continue to be “invisible” to policymakers.
“Until now, many of these ocean variables have not had a market value, and so they have been absent from the calculations,” he notes, adding that this study is the first to assign monetary equivalence values to these “neglected oceanic impacts.”
The team calculates that, without the oceanic impacts, the social cost of carbon stands at about 43 euros per tonne of carbon dioxide emitted into the atmosphere. Including the blue dimension, this value rises to almost 82 euros per tonne, nearly double.
As an example, the researchers say that in 2024 globally about 41.6 billion tonnes of carbon dioxide were emitted, which, according to estimates, means nearly two trillion euros in damages related to the oceanic impacts of climate change in a year of emissions.
The social cost of carbon including the oceans is unequal, the research advances, with islands and smaller economies being the most affected. This is because these populations rely more on marine resources for food and, therefore, are more exposed to health risks, such as malnutrition, since warmer sea waters lead, for example, to less nutritious fish.
