Lula advocated for redirecting some oil exploration profits towards the green energy transition, and said decisions taken now regarding the energy sector will determine humanity's "success or failure in the battle against climate change."

He addressed heads of state and government gathered in the Amazonian city of Belem ahead of an annual round of UN climate talks starting next week.

The summit was snubbed by leaders of some of the world's leading oil, coal and gas producers -- notably the United States whose President Donald Trump has called climate change a "con job."

Lula cautioned that "Earth can no longer sustain the development model based on the intensive use of fossil fuels that has prevailed over the past 200 years."

He pointed to ethanol as an "effective and readily available alternative" for industry and transportation, and lamented "pressure and threats" that led the International Maritime Organization (IMO) to postpone a plan to curb shipping emissions.

Trump had threatened sanctions against countries backing the IMO project and there are fears he could use similar tactics to block progress at the Belem climate conference.

The United States under Trump has announced its withdrawal from the landmark Paris Agreement signed 10 years ago to curb fossil fuel use in a bid to halt global warming.

Lula said that in those ten years, the share of fossil fuels in the global energy mix has decreased "only" from 83 percent to 80 percent.

He added the war in Ukraine "reversed years of efforts to reduce greenhouse gas emissions," causing the reopening of many coal mines.

"Spending twice as much on weapons as we allocate to climate action is paving the way for climate apocalypse," the leftist leader said.

"There will be no energy security in a world engulfed in flames."

Conference host Brazil has itself come under fire for authorizing its state oil company to begin offshore exploration in the Amazon.