MANAUS, Brazil — President Joe Biden toured the drought-shrunken waters of the Amazon River’s greatest tributary Sunday as the first sitting U.S. president to set foot in the legendary rainforest, while the incoming Trump administration seems poised to scale back the U.S. commitment to combating climate change.

The Amazon region, which is about the size of Australia, stores huge amounts of the world’s carbon dioxide, a greenhouse gas that drives climate change when it’s released into the atmosphere. But development is rapidly depleting the world’s largest tropical rainforest and rivers are drying up.

Flying over a stretch of the Amazon in a helicopter, Biden saw severe erosion, ships grounded in the Negro River tributary, and fire damage. He also passed over a wildlife refuge and the expansive waters where the Negro joins the Amazon. He was joined by Carlos Nobre, a Nobel Prize-winning scientist and expert on how climate change is harming the Amazon.

Biden met Indigenous leaders — introducing his daughter and granddaughter to them — and visited a museum at the gateway to the Amazon as he looks to highlight his commitment to the preservation of the region. Three Indigenous women shook maracas as part of a welcoming ceremony.

“I’m proud to become the first sitting president to visit the Amazon,” Biden said before signing a U.S. proclamation designating Nov. 17 as International Conservation Day.

His administration announced plans last year for a $500 million contribution to the Amazon Fund, the most significant international effort to preserve the rainforest, primarily financed by Norway.

So far, the U.S. government said it has provided $50 million, and the White House announced Sunday an additional $50 million contribution to the fund.

“It’s significant for a sitting president to visit the Amazon. ... This shows a personal commitment from the president,” said Suely Araújo, former head of the Brazilian environmental protection agency and public policy coordinator with the nonprofit Climate Observatory. “That said, we can’t expect concrete results from this visit.”

She doubts a “single penny” will go to the Amazon Fund once President-elect Donald Trump is back in office.

The incoming administration is highly unlikely to prioritize the Amazon or anything related to climate change. Trump already said he would again pull out of the Paris Agreement, a global pact forged to avert the threat of catastrophic climate change, after Biden recommitted to it.

Trump has cast climate change as a “hoax” and said he will eliminate energy-efficiency regulations by the Biden administration.

Still, the Biden White House announced new efforts Sunday aimed at bolstering the Amazon and stemming the impact of climate change.

Among the actions is the launch of a finance coalition that looks to spur at least $10 billion in public and private investment for land restoration and eco-friendly economic projects by 2030, and a $37.5 million loan to Mombak Gestora de Recursos Ltda. to support the large-scale planting of native tree species on degraded grasslands in Brazil.

Biden also highlighted that the U.S. is on track to reach $11 billion in spending on international climate financing in 2024, a six-fold increase from when he started his term.

The Amazon is home to Indigenous communities and 10% of Earth’s biodiversity. It also regulates moisture across South America. About two-thirds of the Amazon is within Brazil, and scientists say its devastation poses a catastrophic threat to the planet.

The forest has been suffering two years of historic drought that have dried up waterways. It has made way for wildfires that have burned an area larger than Switzerland and choked cities near and far with smoke.

While Biden is the first sitting president in the Amazon, former President Theodore Roosevelt traveled to the region with the help of the American Museum of Natural History after his 1912 loss to Woodrow Wilson. He was joined by his son and naturalists, and they traversed 15,000 miles during which he fell ill with malaria and suffered a serious leg infection after a boat accident.

Biden is on a six-day trip to South America, the first to the continent of his presidency. He traveled from Lima, Peru, where he took part in the annual Asia-Pacific Economic Cooperation summit and met with Chinese President Xi Jinping.

After his stop in Manaus, he was heading to Rio de Janeiro for the Group of 20 summit.