The US, India and Saudi Arabia are the three countries with the most to lose from climate change. That’s according to the first study to quantify the social cost of carbon – a measure of the economic harm resulting from carbon dioxide emissions – on a country by country basis.
“Our analysis demonstrates that the argument [in the US] that the primary beneficiaries of reductions in carbon dioxide emissions would be other countries is a total myth,” says Kate Ricke of the University of California San Diego, US. “We consistently find, through hundreds of uncertainty scenarios, that the US always has one of the highest country-level social costs of carbon. It makes a lot of sense because the larger your economy is, the more you have to lose.”
Ricke was surprised just how consistently the US is one of the biggest losers, even when compared to other large economies.
To assess the level of economic harm from carbon emissions around the world, Ricke and colleagues used climate model projections, empirical climate-driven economic damage estimations and socioeconomic forecasts. According to their study, the global social cost of carbon is significantly higher than the figure used by the US government to inform policy decisions.
“Evaluating the economic cost associated with climate [change] is valuable on a number of fronts, as these estimates are used to inform US environmental regulation and rulemakings,” Ricke says.
The US Environmental Protection Agency calculates a global social cost of carbon of $12–62 per tonne of carbon dioxide emitted by 2020. This latest research put the global figure at $180–800 per tonne. What’s more, it assessed the social cost of carbon for the US as around $50 per tonne, meaning that the nearly five billion tonnes of carbon dioxide that the US emits each year costs the nation’s economy some $250 billion.
“We all know carbon dioxide released from burning fossil fuels affects people and ecosystems around the world, today and in the future,” adds Ricke. “However, these impacts are not included in market prices, creating an environmental externality whereby consumers of fossil fuel energy do not pay for and are unaware of the true costs of their consumption.”
India’s social cost of carbon was the highest at around $86 per tonne of CO2, followed by the US at $48 per tonne and Saudi Arabia at $47 per tonne. Brazil, China and the United Arab Emirates all had values above US$20 per tonne. Northern Europe, Canada and the Former Soviet Union had negative social cost of carbon values in 2020, the study found, because their current temperatures are below the economic optimum. Under continued warming, however, their social cost of carbon would be likely to become positive.
“Climate decision-making does not occur in a vacuum,” write the researchers in Nature Climate Change. “Some countries, such as northern Europe and Canada, are leaders on climate policy despite potentially negative SCCs [social costs of carbon], whereas other countries with the highest country-level SCCs, like the United States and India, lag behind. Clearly, a host of other strategic and ethical considerations factor into the international relations of climate change mitigation.”
- This article is based on a press release from the University of California San Diego.
