Global warming has caused the Indian economy to be 31% smaller than it would otherwise have been, according to a Stanford study which shows how Earth’s temperature changes have increased inequalities.

The study, PTI reports, has been published in the journal Proceedings of the National Academy of Sciences, showed that growing concentrations of greenhouse gases in Earth’s atmosphere since the 1960s had enriched cool countries like Norway and Sweden while dragging down economic growth in warm countries such as India and Nigeria.

“Our results show that most of the poorest countries on Earth are considerably poorer than they would have been without global warming,” said climate scientist Noah Diffenbaugh, from Stanford University in the US. “At the same time, the majority of rich countries are richer than they would have been,” Diffenbaugh said in a statement.

The study from 1961 to 2010, global warming decreased the wealth per person in the world’s poorest countries by 17 to 30%. Meanwhile, the gap between the group of nations with the highest and lowest economic output per person is now approximately 25% larger than it would have been without climate change.

While the impacts of temperature may seem small from year to year, they can yield dramatic gains or losses over time. “This is like a savings account, where small differences in the interest rate will generate large differences in the account balance over 30 or 50 years,” said Diffenbaugh.