The world has already warmed an average of nearly 1.2C since the mid-1800s, according to a report by global climate scientists released this past week, unleashing a devastating cascade of extreme weather from more intense heatwaves to severe storms.
The continuing impact of the changing climate will result in 73 more deaths per 100,000 people by the end of the century, said Nobel Laureate Esther Duflo, who specializes in issues of poverty at the College de France and Massachusetts Institute of Technology (MIT).
"This may seem an abstract figure but... it's the equivalent of all the deaths from infectious diseases today," said the 50-year-old said.
"Each ton of carbon that is put into the atmosphere costs human lives."
Hardest hit are the most vulnerable people and the world's poorest countries, who have done little to contribute to the fossil fuel emissions that drive up temperatures.
Duflo calls for "a mechanism for taxing countries" on an international scale that's "binding," by either increasing the minimum tax on multinational corporations or taxing the planet's wealthiest.
Part of the tax would go into the bank accounts of those facing the greatest environmental hazards, she said, "for example... people affected by floods, extreme heat, allowing them to move temporarily or permanently so they can adapt to a new way of life."
The rest could be used to fund solutions for adapting life "in these countries that are going to be profoundly transformed," she said.
Parts of India saw temperatures above 44C (111F) in mid-April, with at least 11 deaths near Mumbai attributed to heat stroke on a single day.
Since late 2020, countries in the Horn of Africa like Ethiopia, Kenya, and Somalia have been suffering the region's worst drought in 40 years.
NGOs said that despite the aid poured into the region last year, an estimated 43,000 people died from the drought in Somalia alone in 2022.
Placing the responsibility of on rich nations, Duflo said, "We are imposing an enormous cost on the poorest countries by the way in which we decide to live today."
A pioneer in field experiments that won her the 2019 Nobel prize in economics with her husband Abhijit Banerjee and American economist Michael Kremer, Duflo says the situation is ever-more urgent with extreme poverty on the rise since 2020 after having been halved since the 1990s.
Pointing to widening inequality, she said rich countries spent 27 percent of their GDP on measures to support their populations during the pandemic, while pour countries spent just two percent and global solidarity was "almost at a zero level" when it came to international aid and vaccines.
The war in Ukraine and inflation driving up the cost of necessities has aggravated the situation.
And commitments made at the United Nations climate summits (COP) have repeatedly fallen short, she said.
Countries have never, for example, respected their pledges of $100 billion each year toward a climate transition fund for poor countries and haven't found the funding to support a loss and damages scheme announced during the COP27 summit in Egypt.