A large proportion of the world’s countries could dodge the worst economic impacts of climate change if average global warming were held to 1.5°C, rather than the top-line 2.0°C target in the Paris agreement, according to a paper published last week in the journal Philosophical Transactions A.
The paper “finds that per capita GDP would be 5% higher by 2100 if temperatures are stabilized at 1.5°C above pre-industrial temperatures rather than 2.0°C,” Carbon Brief reports. Those benefits would accrue most to the world’s poorest countries, since that’s where the economic impacts of 2.0°C average global warming would be disproportionately larger.
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“The new research also suggests that countries which are poorer now will see larger reductions in per capita GDP growth due to climate change,” the UK news outlet notes. “The effects here are larger for 2.0°C than for 1.5°C.”
“In other words, countries that are poor today are expected to become poorer with climate change, and even more so for 2.0°C relative to 1.5°C, while countries that are rich today are likely to be impacted less,” said lead author Felix Pretis, co-director of the Oxford University Climate Econometrics Project. “This implies that future climate change may increase inequality across countries.”
In a new approach to a branch of economic analysis that has been difficult and subject to criticism, the research team estimated the effects of global warming on future rates of annual economic growth. “In an effort to base these on historical data, the research models the past relationship between GDP growth and climate variables such as temperature and rainfall,” Carbon Brief explains, then combines those results with climate simulations to project impacts on future economies.
“The results show significant differences between 1.5°C and 2.0°C of warming,” Carbon Brief notes. While the majority of countries see lower annual growth at 2.0°C compared with no warming, “the impacts of 1.5°C warming on yearly growth rates are found to be ‘near indistinguishable’ from no warming on a global average basis.” While some regions see some loss—less than they would at 2.0°C—“the values are not statistically different from zero.”
By 2100, the study projects an 8% median drop in per capita GDP at 1.5°C, versus 13% at 2.0°, though the authors point to “many uncertainties in their projections of the relationship between climate and economic outcomes and how an average global temperature rise will be spread between countries.”
University of Chicago public policy professor Amir Jina, who was not involved with the study, suggests similar uncertainty around the headline 5% difference in GDP impact between 1.5° and 2.0°C average global warming.
“We could state the result in a different way—that we think that if there are damages evident at even 1.5°C, we should be taking that into consideration with urgency and exploring our mitigation options,” he told Carbon Brief.