The Brazilian Institute for Applied Economic Research (Ipea), a body under the Ministry of Planning and Budget of Brazil, recently released a study indicating that considering the excessive carbon emissions by developed countries into the atmosphere, they collectively owe a staggering $97.5 trillion (approximately 516 trillion Brazilian reais) in "climate debt" to the world.

According to a report by the Brazilian newspaper "O Estado de S.Paulo" on November 16th, the study is based on the global carbon budget estimated by the Intergovernmental Panel on Climate Change (IPCC) to calculate the remaining carbon emission quota since 1990. Researchers allocated the remaining quota based on each country's population proportion, setting emission limits for each country, with those exceeding them considered debtors.

To quantify this climate debt, the study employed the "social cost of carbon emissions" index, indicating that emitting an excess of 1 ton of carbon dioxide would lead to $417 in economic and social losses, such as those caused by extreme climate events.

The research data shows that since 1990, the United States' carbon emission quota should have been 571 billion tons of carbon dioxide, but the actual emissions reached 1,830 billion tons, resulting in a climate debt of approximately $46.6 trillion, ranking it at the top globally. Japan follows in second place, with a climate debt of about $9.4 trillion.

Simultaneously, Brazil has emitted 591 billion tons of carbon dioxide since 1990, which is about 1.6 times its emission quota (368 billion tons), resulting in a climate debt of $8.7 trillion, placing it third globally.

Rodrigo Fracalossi, one of the researchers from the Institute for Applied Economic Research involved in the study, emphasized that developed countries remain the primary culprits in climate change, with Brazil being a special case where its carbon emissions mainly stem from deforestation. He stressed, "The later a country industrializes, the smaller its emission impact, as global energy efficiency significantly improves over time."

The research suggests taxing global billionaires and establishing a minimum tax rate for multinational corporations to raise funds to offset the climate debt. Fracalossi believes that the significance of this study lies in concretizing the discussion on climate fairness. "Talking philosophically about injustice is essential, but only by quantifying it and comparing it against each country's commitments can we better understand the severity of the issue."

At the 29th United Nations Climate Change Conference (COP29) held in Baku, Azerbaijan in 2024, it was determined that developed countries need to provide $300 billion annually for climate finance to developing countries by 2035, with a total target of $1.3 trillion. However, this only represents 1.43% of the total climate debt owed by developed countries. This issue continues to be a key topic in climate negotiations, including at COP30 held in Belém, Brazil.

The study further points out that repaying the climate debt is "not a punishment but a compensation mechanism." For instance, in the case of Brazil, the debt could be offset through ecological restoration of degraded areas, afforestation, among other methods.

Finally, the research notes that while the United Nations Framework Convention on Climate Change and the Paris Agreement acknowledge the unequal impacts of climate change on countries, they have not actively addressed the issue of "historical responsibility." "Past excessive emitters have utilized a portion of the limited atmospheric carbon storage capacity that rightfully belongs to all humanity, hence the need to establish a clear compensatory mechanism."