Hidrelétricas da Amazônia podem perder até 40% de força de geração nos próximos anos

 

Trecho de vazão reduzida do rio Xingu sofre com redução de água devido à barragem de Belo Monte, no Pará - Lalo de Almeida 20.set.22/Folhapress 

 

by  André Borges

 

 

 

Brasília

O protagonismo da geração hidrelétrica está em xeque. Grande parte das usinas da Amazônia poderá sofrer reduções drásticas em seu potencial de geração de energia elétrica, com perdas projetadas entre 30% e 40% nas próximas décadas, devido aos impactos das mudanças climáticas.

A conclusão faz parte de um novo estudo da ANA (Agência Nacional de Águas e Saneamento Básico) sobre as projeções climáticas para o regime de chuvas, vazões de rios e a segurança hídrica no Brasil nas próximas décadas. A redução projetada considera um horizonte de quatro décadas, até 2065.

Caso os investimentos em novos projetos continuem baseados apenas em dados históricos, especialistas alertam que o país pode ver uma onda de usinas incapazes de produzir a energia esperada, resultando em aumento de custo para o consumidor e dependência de termelétricas fósseis.

 

Segundo o relatório "Impacto da Mudança Climática nos Recursos Hídricos do Brasil", a queda na produção seria uma consequência de mudanças que podem ocorrer no padrão de fluxo natural das águas por causa do aquecimento global.

Ao observar o comportamento já verificado das vazões médias dos rios no período de 1950 a 2014, o documento projeta o desempenho no futuro próximo, até 2065, e para tempos mais distantes, num horizonte até 2100. O resultado aponta que a região Norte é a com maior risco de ser afetada.

Enquanto Sul, Sudeste e Centro-Oeste tendem a registrar diminuições de até 10% na geração hidrelétrica, a Amazônia pode enfrentar perdas maiores devido à redução de vazões, afetando usinas de grande porte já instaladas e os empreendimentos planejados para os próximos anos.

"Considerando que a geração de energia seja diretamente relacionada à vazão média afluente, as regiões Sul, Sudeste e Centro-Oeste mostram reduções de 0(zero)-10%, enquanto a região Norte apresenta as projeções mais pessimistas, com alterações de 30-40%", afirma o estudo.

 

"Dentre os empreendimentos existentes, os maiores impactos se concentram nas usinas com maior potência instalada, a maioria delas localizada na bacia Amazônica", continua o documento.

O estudo da Agência Nacional de Águas aponta que, se nada for ajustado, a expansão hidrelétrica brasileira corre o risco de ser planejada com base em um cenário climático que não existirá mais.

Nas últimas duas décadas, o país apostou na Amazônia como a última grande fronteira hídrica para ampliar sua capacidade hidrelétrica, com a construção de usinas como Belo Monte, no rio Xingu, e Santo Antônio e Jirau, no rio Madeira.

Ocorre que, segundo o documento, essas usinas foram projetadas levando em conta séries históricas de vazões que já não representam mais o padrão futuro dos rios. Com o prolongamento das estações secas e a antecipação da perda de umidade no solo, fenômenos já observados anualmente no Xingu e no sul do Amazonas, o ciclo de água na região está vivendo uma fase de mudança estrutural.

 

No rio Amazonas, houve um aumento na ocorrência de cheias e secas extremas nas últimas décadas. Se considerado o período dos últimos 125 anos, nota-se que, entre as dez maiores cheias ocorridas na região, sete se deram nos últimos 16 anos, a partir de 2009.

No caso das secas, entre os 10 menores níveis observados, 5 ocorreram nos últimos 28 anos. Em 2023 e 2024 a região registrou duas secas seguidas sem precedentes, com níveis de água muito abaixo do que já havia sido observado no passado.

A ANA sustenta que incorporar cenários climáticos futuros ao planejamento de longo prazo não é apenas uma recomendação técnica, mas uma necessidade para evitar perdas financeiras e insegurança energética.

O Brasil possui hoje 216 gigawatts de potência de energia elétrica, com mais de 24 mil usinas em operação comercial, segundo a Aneel (Agência Nacional de Energia Elétrica). Metade dessa geração vem da força dos rios, com 50,5% atrelada a usinas hidrelétricas de todos os portes.

O estudo reforça que os efeitos não se limitam à geração elétrica. A redução de vazões também vai afetar a irrigação, o abastecimento urbano e a biodiversidade, caso o planejamento dessas áreas não passe a incorporar as projeções climáticas.

 

Os resultados indicam que as mudanças climáticas na hidrologia deverão mexer com a segurança hídrica em boa parte do Brasil, enquanto outras regiões devem sofrer com o aumento de enxurradas e alagamentos urbanos, como se viu no Rio Grande do Sul em 2024.

Do lado do poder público, a falta de recursos financeiros tem comprometido o enfrentamento do problema, afirma a ANA. "A sustentabilidade política das políticas hídricas e climáticas segue ameaçada por cortes orçamentários, descontinuidade institucional e ausência de uma política de Estado que una água e clima de forma duradoura", diz a agência no documento.

A ANA afirma que uma eventual mudança de postura "exige blindagem orçamentária, maior participação social e inovação normativa, de modo a reconhecer a incerteza como ponto de partida para garantir segurança hídrica em cenários climáticos cada vez mais instáveis".

‘Ghost resorts’: as hundreds of ski slopes lie abandoned, will nature reclaim the Alps? With the snow line edging higher, 186 French ski resorts have shut, while global heating threatens dozens more.

 

The skeletal remains of a once-busy ski lift in Céüze 2000, in France’s Hautes-Alpes department. The resort, which had welcomed skiers for 85 years, never reopened after March 2018 as smaller snowfalls in successive seasons made it unviable. Photograph: Thomas Valentin/The Guardian

 by Phoebe Weston in Céüze

When Céüze 2000 ski resort closed at the end of the season in 2018, the workers assumed they would be back the following winter. Maps of the pistes were left stacked beside a stapler; the staff rota pinned to the wall.

Six years on, a yellowing newspaper dated 8 March 2018 sits folded on its side, as if someone has just flicked through it during a quiet spell. A half-drunk bottle of water remains on the table.

The Céüze 2000 resort when snow was plentiful.

 

 

The Céüze resort in the southern French Alps had been open for 85 years and was one of the oldest in the country. Today, it is one of scores of ski resorts abandoned across France – part of a new landscape of “ghost stations”.

More than 186 have been permanently closed already, raising questions about how we leave mountains – among the last wild spaces in Europe – once the lifts stop running.

 

As global heating pushes the snow line higher across the Alps, thousands of structures are being left to rot – some of them breaking down and contaminating the surrounding earth, driving debate about what should happen to the remnants of old ways of life – and whether to let nature reclaim the mountains.

Snowfall at Céüze started becoming unreliable in the 1990s. To be financially viable, the resort needed to be open for at least three months. In that last winter, it only managed a month and a half. For the two years before that it had not been able to operate at all.

Opening the resort each season cost the local authority as much as €450,000 (£390,000). As the season got shorter, the numbers no longer added up. To avoid a spiral of debt, the decision was made to close.

The resort closed permanently during the 2020 winter due to a lack of snow. Photograph: Thomas Valentin/The Guardian

“It was costing us more to keep it open than to keep it closed for the season,” says Michel Ricou-Charles, president of the local Buëch‑Dévoluy community council, which oversees the site. Even under the most optimistic projections, the future looked bleak. “We looked into using artificial snow, but realised that would delay the inevitable,” he says.

It was seven years before the trucks and helicopters came in to begin removing the pylons. Still, the local community grieved for the small, family-oriented resort, which was host to generations of memories. As demolitions began, they came to take nuts, bolts and washers as mementoes of what they had lost.

Degrading wild terrain

In France, there are today 113 ski lifts totalling nearly 40 miles (63km) in length that have been abandoned, nearly three-quarters of them in protected areas. It is not just ski infrastructure. The Mountain Wilderness association estimates that there are more than 3,000 abandoned structures dotted around French mountains, slowly degrading Europe’s richest wild terrain. This includes military, industrial and forestry waste, such as old cables, bits of barbed wire, fencing and old machinery.

There are 113 abandoned ski lifts in France, nearly three-quarters of which are in protected areas. Photograph: Thomas Valentin/The Guardian

Céüze ski resort is fast becoming one of these pollutants. The little wooden cabin at the bottom of the first button lift is shedding insulation. Ropes once used to mark out the piste hang in tatters and bits of plastic are falling off a pylon. The old sheds at each end of the ski lifts often still contain transformers, asbestos, motor oils and greases. Over time, these substances seep into the soil and water.

Corrosion and rust from metal structures left over from the second world war, such as anti-tank rails and metal spikes, have led to changes in plant species in the surrounding area, potentially offering a vision of what could happen if pylons are left to rust over the coming decades.

 

“In Latin, we say memento mori – remember that you are mortal. Don’t think that you are making eternal things; they will end up becoming obsolete,” says Nicolas Masson, from Mountain Wilderness, which is campaigning for old ski infrastructure to be dismantled to make space for nature. “When you make them, ask yourself the question: what will remain?”

Some believe the resorts should remain memorialised landscapes, honouring generations of people who lived and skied here; others believe they should be returned to wild landscapes with their disintegrating machinery removed.

Ecologist Nicolas Masson is part of a campaign to dismantle old ski infrastructure. Photograph: Thomas Valentin/The Guardian

 

  

Nature’s recovery

Céüze’s deconstruction started on 4 November 2025, a month before the ski season would once have kicked off. The resort’s ski lifts were airlifted out using a helicopter to minimise environmental disturbance and compression of the earth.

French law requires ski lifts to be removed and dismantled if they are no longer in use. The law only applies to ski lifts built after 2017, however. Most last for 30 years, so no lifts would be considered obsolete until at least 2047. The process is also expensive: dismantling Céüze will cost €123,000. This means most abandoned ski infrastructure is left to disintegrate in situ. What is happening in Céüze is rare.

With pylons cleared and the resort already closed for seven years, early signs of ecological recovery are already visible. A red haze floats over the white snow: winter berries of the dog rose are sprouting where the piste is no longer mown.

Berries can be see on dog rose shrubs which are starting to flourish now the piste is no longer cleared for skiers. Photograph: Thomas Valentin/The Guardian

 

The berries are important winter food for birds such as the rare red-billed chough, and their thorny stems are used for nest-building come spring. In the summer, orchids and yellow gentians bloom over these hillsides. The hills surrounding the site are classed as Natura 2000, meaning they are home to Europe’s rarest and most protected wildlife.

The trees are coming back too. “I don’t know if it would take 10, 20 or 50 years, but this is becoming a forest,” says Masson.

 

Wild boar and roe deer living in these forests will benefit from quieter winters. Birds such as grouse shelter from severe cold in winter by digging into the snow, and prefer deep powdery snow – just like skiers. The species is endangered in all the mountain ranges of France.

The dismantling of Céüze comes at a time when many spaces for nature are shrinking. Pierre-Alexandre Métral, a geographer at the University of Grenoble Alpes, who studies abandoned ski resorts, says: “There is a lot of debate about the nature of this dismantling – is it just removing mechanical stuff, or are we attempting to put mountains back into a kind of original state?”

Ecological recovery can be filled with surprises, he says, noting that the maintenance of pistes can be beneficial to some alpine flowers. “If we let nature come back spontaneously – in a wild, uncontrolled way – there are also risks that some invasive species that tend to be stronger could colonise faster,” says Métral.

The hills around the former resort are home to some of Europe’s rarest and most protected wildlife. Photograph: Thomas Valentin/The Guardian

There is scant research in this area, but studies from the Valcotos ski resort closure in Madrid’s Sierra de Guadarrama in 1999 show it led to significant recovery of native vegetation and cleaner waterways, while reducing soil erosion.

“These are laboratories of what the mountain could be like in the future with new closures,” says Métral.

On the brink

The question of what to do with these places will play out across Europe’s mountains, and around the world. Skiing is disappearing from many alpine landscapes. “Many lower ones are already closed,” says Masson. “A fraction of a degree changes everything in the mountain environment. It’s the difference between having snow and no snow.”

 

Research suggests that with 2C (3.6F) of global heating, more than half of existing resorts risk having too little snow. Higher altitude resorts are vulnerable to the loss of permafrost, threatening pylons that have been drilled into it. Some resorts, such as St-Honoré 1500, were abandoned before construction was even completed. Even bigger resorts, which typically have funds to invest in new pistes and artificial snow, are struggling to survive.

For some, the loss of Céüze feels premature. Richard Klein,who lives in Roche des Arnauds, near Céüze, feels the ski resort could – and should – have been saved. “It’s a wonderful place to learn to ski – it’s the best. I think it’s really stupid they closed it,” he says. “There were always loads of people.” Klein believes the local authority should have begun using artificial snow, adding: “Now it’s too late.”

 

Yet life has not disappeared from Céüze. In October 2025, the resort’s Hotel Galliard is being sold to a developer looking to open it for events, according to Ricou-Charles. A property developer has bought the children’s holiday residence, and a carpenter has moved into the building where the old ticket office was. The rooms used as a holiday camp for children have cracks appearing down the side, but might open again in the future.

“Céüze will continue to live, despite the loss of the resort,” says Ricou-Charles. “We are not mourning Céüze because it is not dead.”

On winter weekends dozens of cars still gather in the car park, with people enjoying quieter activities on the hillside, such as walking, snow-shoeing, cross-country skiing and sledging.

A poster from the resort’s 80th anniversary celebrations. Photograph: Thomas Valentin/The Guardian

Masson does not like the term “ghost resort” because it suggests total abandonment when what is happening in his area is more complicated. “People continue to come,” he says. “We don’t need large machines to make mountains attractive.”

What happens at Céüze is a glimpse into a future that faces dozens of other small resorts, and mountain landscapes, across Europe. “What is our heritage that we will want to keep,” asks Masson. “And what is just a ruin we want to dismantle? That is a question we have to ask every time, and it requires some reflection.”