Kerry also gave his firmest indication yet that the United States was willing to engage on compensating poor nations that have already been hit hard by climate change, set to be a major agenda item at the talks known as COP27.

In Brazil, where the Amazon plays a vital role counteracting the planet's carbon emissions, leftist former president Luiz Inacio Lula da Silva triumphed in Sunday's elections against the far-right incumbent Jair Bolsonaro, an ally of agribusiness in the rainforest.

Lula in his victory speech pledged to work toward zero deforestation.

"President-elect Lula is committed," Kerry told reporters in Washington, pointing to Lula's efforts as president in the century's first decade on the environment.

"Now I hope we'll be able to refine that program and move forward even more rapidly with the reforms that are necessary in order to try to save the Amazon," Kerry said.

"Under the Bolsonaro government, regrettably, the level of deforestation increased in the Amazon and it is at perilous high levels today."

Kerry insisted he was not "tone deaf" to economic concerns around the world including in Brazil, Latin America's biggest economy, noting that many residents of the Amazon made a living on cattle or logging.

"We in the rest of the world are going to have to recognize that if we're going to value this great forest, we have to help them to be able to preserve it," he said.

Kerry, a former secretary of state and key architect of the 2015 Paris accord, has returned to his globe-trotting in his climate role, recently visiting Mexico as part of efforts to mobilize action ahead of COP27.

He said he expected more countries to raise their ambitions in coming days through their so-called Nationally Determined Contributions, plans they submit under the Paris agreement.

"We will have a major announcement, which President (Andres Manuel) Lopez Obrador has agreed to, with respect to what Mexico is now going to undertake," Kerry said.