Rising heat and falling yields plague an Amazon island near COP30 host

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COMBU ISLAND, Brazil — Brazilian poet and songwriter Ruy Barata, born in 1920 in Santarém, in Brazil’s Amazonian state of Pará, once wrote ballads that captured the essence of ribeirinhos, the riverside people across the country. “This river is my street. Mine and yours, mururé,” he wrote, in lyrics that elegantly celebrate the traditions of communities living along riverbanks in the Amazon — a region where peoples, forests and rivers coexist in peace. Local inhabitants use the word mururé to designate several species of aquatic plants that can be easily seen in waterways throughout this part of Brazil.

However, the natural life that once inspired Barata’s poetry is now under threat.

The story takes us to Combu Island, a 10-minute boat ride from Pará’s capital, Belém. In November, the city will host the 30th United Nations Climate Change Conference, or COP30. But as the event draws near, the island is seen as a textbook example of the risks posed by unregulated human activity, biodiversity loss and shifting climate patterns. In a collaborative investigation by journalists and scientists, led by Brazil’s science-fostering Serrapilheira Institute and the Latin American Center for Investigative Journalism (CLIP), we examine how the deterioration of the Amazon Rainforest is interrupting vital environmental services — such as the upkeep of local biodiversity and preservation of water cycles — provided by the region.

Combu Island is surrounded by the muddy waters of the Guamá River, named after its brownish color. Spanning about 1,500 hectares (3,700 acres), the island is the fourth-largest of the 42 that make up Belém’s insular region, which is regularly affected by tidal flooding. Here, residents rely on pile-dwelling construction, with houses, restaurants, schools and even health facilities built on stilts — and often with stunning river views. For local riverside peoples, the watercourse is more than just a transport passage; it’s a living territory, essential to their identity and survival.

Combu is home to nearly 1,500 people, according to Pará’s Institute of Forest Development and Biodiversity (Ideflor‑Bio), the state agency responsible for the Combu Island Environmental Protection Area (APA, in Portuguese). Nearly 60% of Pará’s territory is currently under some form of protection, so the Combu APA — set to turn 28 years old ahead of the start of COP30 — plays an important role in local conservation. Its longtime dwellers serve as “living witnesses” to the transformations their island has undergone in recent times.

One of these “supervisors” is Prazeres Quaresma, whose family has called Combu Island home for the last three generations. Her grandfather arrived in 1914, at the end of the Amazon’s rubber boom, when industrial demand for tree-extracted rubber tormented Amazonian areas across South America, and began cultivating cacao. Later, following Brazil’s cacao crisis, a period in which the fruit’s extraction was severely damaged by climate issues, market fluctuations and fungal disease, he switched to açaí.

Decades later, in the 1980s, her father, José Anjos, became the founder of one of Combu’s most iconic restaurants: Saldosa Maloca, a name inspired by “Saudosa Maloca,” or “Nostalgic Shack,” a famous 1950s samba song by well-known Brazilian songwriter Adoniran Barbosa. Today, the Maloca is managed by 56-year-old Prazeres. On its social media accounts, it describes itself as an “eco-restaurant,” offering customers immersive Amazonian experiences. These include paying a visit to a 400-year-old giant samaúma tree (Ceiba pentandra), affectionately called “the queen of the forest.”

“I always say that Combu and I have an intimate relationship. Most of my family lives here. That’s why we worry about the future of the island,” Quaresma says. Besides offering dishes that feature Amazonian cuisine, like fish recipes using tambaqui (Colossoma macropomum) and piraíba or filhote (Brachyplatystoma filamentosum), she owns a small local farm.

Now, her source of income is feeling the sting of the ongoing environmental shifts.

Over the past two years, rising temperatures and intensifying droughts have compromised Quaresma’s fruit production. “It was terrible. After one intense drought, we believe it will be better in the following year. But sometimes it gets worse. And we never prepare for the worst, as we are always expecting an improvement.”

But climate change has impacted more than just the yields of açaí, cacao and cupuaçu, another typical Amazonian fruit.

“A few years ago, I remember we had to cover ourselves in bed due to cold weather. Today, we sleep completely uncovered and even have to turn the fan on. Can you imagine how much [the temperature] has increased? How much are the changes affecting our lives?” Quaresma says.

The city of COP30 becomes the face of climate change

Her feelings and observations are now backed by science. For three months, our reporting team worked alongside scientists Maria Luiza Busato and Luís Cattelan, from the Serrapilheira Institute’s Quantitative Ecology Training Program. They analyzed Belém’s precipitation, temperature and humidity trends, based on data from 1981-2024 sourced from two National Institute of Meteorology stations.

The results show that the city has become increasingly warmer and drier since the early 1980s, with average temperatures rising by 1.32° Celsius (2.38° Fahrenheit) over the past 40 years. Meanwhile, relative humidity — the proportion between existing air moisture and the maximum humidity at a given temperature — dropped by 2.64%.

Additionally, the climate situation has become increasingly intense between June and November, during the so-called Amazonian summer, the region’s driest season. During this period, temperatures increased by 1.86°C (3.35°F) and humidity fell by 5.3%.

The climatic changes also pose devastating risks to riverside families relying on açaí-sourced income. According to a study by the Brazilian Agricultural Research Corporation (Embrapa), conducted in the eastern part of the Amazon region, Pará’s production of unirrigated açaí in floodplains decreased by 15-20% in 2024. The drop reaches 40% when it comes to irrigated crops developed in regular upland.

“In our monitored plantations, there were many signs of something excessive during the driest periods. And it was the air temperature,” says Alessandro Carioca, an Embrapa researcher and specialist in Amazonian forest and agricultural ecosystems meteorology.

Carioca tracks açaí, cacao, cupuaçu and dendê oil palm crops in Tomé‑Açu and Moju, two municipalities in northeastern Pará. For several days, he observed that maximum daily temperatures repeatedly surpassed the long‑term average. “The issue became more evident when harvest workers began reporting that açaí flowers were being ‘aborted,’ fruits did not have filling, and the vitality of plants was declining — even with leaves dying,” he says.

The challenge of living on dry, warm, unbreathable days

The crisis plaguing the northeast of Pará extends to Belém, some 200 kilometers (124 miles) away. “Last summer, many cupuaçu, peach palm [pupunha] and guava trees died,” says local artisan Silvia Rosa. “They completely dried out, from the fruit to the trunk.”

A resident of Combu since the age of 5, Rosa makes bio-jewelry crafted from Amazonian leaves and seeds. As recently reportedby Mongabay, sustainable craftwork has become an alternative source of income for residents of various Amazonian states. It’s a similar story on this island, although the future is uncertain.

Rosa says she’s used to enduring long treks across the island in search of raw materials that can be transformed into products for sale. However, climate impacts are changing her work routine. “In the past, I entered the forest to collect seeds and ended up covered in mud. Not anymore: [nature] is much drier now. We can feel the difference. It is drier and warmer, too.”

In 2024, 46 out of Pará’s 144 municipalities experienced more than 150 days of extreme heat, making it the state with the most cities in Brazil hit by abnormally high temperatures during the period.

Belém and the city of Melgaço (with Brazil’s lowest Human Development Index), on Marajó Island, stood out in terms of “heat stress events,” according to the Brazilian Center for Natural Disaster Monitoring and Alerts (CEMADEN), based on satellite data from the country’s National Institute for Space Research (INPE).

The upcoming COP30 host city alone has already registered 212 consecutive days with temperatures reaching 37.3°C (99.1°F), which is up to 5°C (9°F) above the average highest temperature recorded over the past decade. The situation draws attention, even in a city familiar with warm weather.

Due to alarming forest fires, Belém also had days of unbreathable air.

Drought-plagued residents were also at significant risk of facing a worsening water crisis, provoked by high temperatures and low humidity, creating additional adverse conditions such as lower rainfall patterns, likewise related to El Niño.

The crisis is also affecting the Guamá River, suffering from a prolonged period of rising salinity in recent times. “[The increase] always happens during summer, when the river’s water turns greenish and more saline,” says restaurant owner Quaresma. “However, it used to last no more than a month. Last year, we had around three months of salty water.”

Biologist Vania Neu, from the Federal Rural University of the Amazon, says the phenomenon is a natural response to a distinct environmental condition. “In estuaries [regions where freshwater merges with the ocean] such as this one, near the Atlantic Ocean, extreme droughts and significantly low river flow lead the ocean to push further upstream of the river.”

Unusual saline levels bring many environmental risks

Since 2023, Neu and researchers from Pará and the southern states of São Paulo and Rio de Janeiro have been studying the estuary of the Pará River, which includes the Guamá River and Guajará Bay, responsible for bathing the surroundings of Belém and nearby islands.

“It is disturbing to look in the long run and see the intensification of extreme weather events — like droughts — that we once saw with bigger intervals,” Neu says. “The higher frequency [of atypical climate conditions] and growing water salinity levels bring water insecurity to the population.”

Local açaí cultivation has also been impacted — and beyond the limits of Pará state. In a 2023 study, Federal University of Acre geographers Cristóvão Henrique Ribeiro da Silva and Raylene Cameli described similar declines in Amapá state’s Bailique archipelago, in the estuary of the Amazon River, with reports of fruit-dependent families harvesting salty açaí berries.

The scenario is alarming as droughts in the Amazon have grown more frequent this century. While the region experienced seven drought events between 1960 and 1990, in the last two decades the number jumped to eight — four of which were considered extreme (2005, 2010, 2015-2016, and 2023-2024).

In recent decades, Combu has become a tourism jewel for Belém. The growing interest of travelers, however, has brought social, environmental and cultural impacts — mostly due to a lack of regulation.

Under environmental protection since 1997, the island relies on these guidelines to secure biodiversity conservation and keep human occupation under control. The main objective is to ensure the sustainable use of natural resources.

The island began to be progressively occupied after electricity arrived in 2011, especially near the Combu stream, where most bars and restaurants have been established. However, it was only this year — and after popular protests and mounting pressure — that Ideflor-Bio addressed management plans for the protected area.

The rearrangement of Combu’s social landscapes is measured in numbers. A March 2025 reportby the Amazon Foundation for Support of Studies and Research of Pará (Fapespa) examined the sustainability status of Belém-orbiting islands, showing that, between 2002 and 2023, the amount of “cleared areas” increased nearly tenfold — from 12.4 to 123.7 hectares (30.6 to 305.7 acres).

Meanwhile, it says, “dense rainforest” shrank by 6.26% and water bodies by 30.6%, while human occupation went up by a factor of 49.

Prazeres Quaresma, who is also a tourism expert, upholds community-led tourist activities as an alternative to the present occupation scenario. “We believe it is possible to bring economic development to the island without destroying it. Urbanization is not the right answer. People visiting Combu must seek a forest experience.”

She says she’s equally worried about the disappearance of the riverside people’s identity. She says routine practices, such as river bathing and taking a ride in the cascos (what locals commonly call their canoes), could be lost.

“When we used to bathe in the river as children, you could see people playing hide-and-seek and tag in the water. This is no longer possible nowadays, as the waters are stuffed with high-speed boats. The younger generations are losing the connection with the river,” Quaresma says.

Silvia Rosa, the artisan, raises similar concerns. She says her two children, a boy and a teenage girl, can’t play in the water as the risk of accidents is ever-present. For her, living in harmony with nature comes with respect. “By respecting it, we reap its benefits — and sustain ourselves from it.”

On each journey to the forest, the bio-jeweler practices what she has been taught by her father-in-law, a veteran açaí harvester. “Since he was a kid, he was familiar with the forest. In Combu, many lives revolve around açaí. That’s why kids start early and learn everything. My father-in-law knows the forest, every seed, every leaf, what it is and what it is for.”

Rosa and Quaresma are two Amazonian women whose roots grow deep from the heart of Combu. Asked about the upcoming COP30, they raise their voices and ask for help. “We hope it is not just yet another global gathering to discuss climate,” Quaresma says. “Climate has already been discussed. What we need is measures to mitigate the damage that has already been done. I hope the conference brings effective solutions and not just speeches.”

Banner image: A Combu Island riverside resident navigates between Amazonian trees. Image by Caroline Moraes via Wikimedia Commons (CC BY-SA 4.0).

This special report was supported by O Liberal as part of a collaborative project between Latin American journalists and scientists, led by Serrapilheira Institute, from Brazil, and the Latin American Center for Investigative Journalism (CLIP), aimed at exploring how biodiversity damage in the Amazon disrupts the continent’s various environmental services.

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Alexandre de Santi Editor

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