According to a new paper published on 22 April in Proceedings of the National Academy of Sciences, global warming may increase global inequality (1). In fact, the new findings seem to suggest that since the 1960s, poorer countries are becoming poorer while rich countries are getting richer.
For the past 50 years, overall between-country inequality has been decreasing, however, if these latest estimates are correct, the gap would have narrowed much faster without climate change.
Studies previously showed economic outputs are highest at an average temperature of 13 degrees Celcius. Whereas, extreme cold affects the agricultural sector and hotter temperatures can also damage crops, make workers less productive, and magnify social conflict.
What would the global economy look like without global warming?
Building on previous studies published in Nature and in Science (2,3), the researchers from Stanford University combined historical temperature trajectories from more than 20 climate models global climate models with proven relationships between historical temperature fluctuations and economic growth.
Then, using this information, they derived country-level estimates of the influence of human-induced global warming on economic growth. In addition, they accounted for other factors such as technological innovation and fluctuations in the global economy.
By first determining how the amount of warming each country already experienced due to anthropogenic climate change, the researchers were able to estimate what each country’s economic output could possibly have been without warming.
Not quite 100 per cent certain, but certainly food for thought
The researchers discovered an extremely high probability (90 per cent) that anthropogenic warming makes inequality between countries worse. According to the results, during warmer than average years, economies of cooler nations accelerated, whereas warm nations experienced more sluggish economic growth.
Between 1961 to 2010, wealth per person decreased in the world’s poorest countries decreased (in relative terms) by 17 to 30 per cent owing to climate. Furthermore, the gap is growing between nations with the highest and lowest economic output per person — and is 25 per cent larger than it would be without global warming.
However, it is less clear how global warming may affect economic growth in mid-latitude countries, such as the US, some nations of Europe, and China.
What causes between-country differences?
The findings suggest that the direct benefits of fossil fuel use are not distributed equally among countries of the world. In addition, many poor countries are harmed by global warming caused by energy consumption in wealthier countries.
Furthermore, yearly changes may seem small but can gradually accumulate, over say 30 or 50 years, resulting in significant losses for some nations. For instance, the researchers showed that as a result of small incremental effects, the Indian economy may be 31 per cent lower than it would have been in a world without global warming.
(1) Diffenbaugh, N.S. and Burke, M. Global warming has increased global economic inequality. Proceedings of the National Academy of Sciences (2019). DOI: 10.1073/pnas.1816020116
(2) Burke, M., Hsiang, S.M., and Miguel, E. Global non-linear effect of temperature on economic production. Nature (2015). DOI: 10.1038/nature15725
(3) Hsiang, S. et al. Estimating economic damage from climate change in the United States
science (2017). DOI: 10.1126/science.aal4369