Climate crisis ‘wreaking havoc’ on Earth’s water cycle

Global heating is supercharging storms, floods and droughts, affecting entire ecosystems and billions of people

The climate crisis is “wreaking havoc” on the planet’s water cycle, with ferocious floods and crippling droughts affecting billions of people, a report has found.

Water is people’s most vital natural resource but global heating is changing the way water moves around the Earth. The analysis of water disasters in 2024, which was the hottest year on record, found they had killed at least 8,700 people, driven 40 million from their homes and caused economic damage of more than $550bn (£445bn).

Rising temperatures, caused by continued burning of fossil fuels, disrupt the water cycle in multiple ways. Warmer air can hold more water vapour, leading to more intense downpours. Warmer seas provide more energy to hurricanes and typhoons,

supercharging their destructive power. Global heating can also increase drought by causing more evaporation from soil, as well as shifting rainfall patterns.

Deadly flash floods hit Nepal and Brazil in 2024, while river flooding caused devastation in central Europe, China and Bangladesh. Super Typhoon Yagi, which struck south-east Asia in September, was intensified by the climate crisis, as was Storm Boris which hit Europe the same month.

Droughts also caused major damage, with crop production in southern Africa halving, causing more than 30 million people to face food shortages. Farmers were also forced to cull livestock as their pastures dried up, and falling output from hydropower dams led to widespread blackouts.

“In 2024, Earth experienced its hottest year on record and water systems across the globe bore the brunt, wreaking havoc on the water cycle,” said the report’s leader, Prof Albert van Dijk.

He said 2024 was a year of extremes but that was not an isolated occurrence. “It is part of a worsening trend of more intense floods, prolonged droughts, and record-breaking extremes.” The report warned of even greater dangers in 2025 as carbon emissions continued to rise .

The 2024 Global Water Monitor Report was produced by an international team of researchers from universities in Australia, Saudi Arabia, China, Germany and elsewhere. The team used data from thousands of ground stations and satellites orbiting the Earth to assess critical water variables such as rainfall, soil moisture, river flows, and flooding.

They found rainfall records are being broken with increasing regularity.

For example, record highs for monthly rainfall were set 27% more often in 2024 than in the year 2000 and daily rainfall records were set 52% more frequently. Record lows were set 38% more often. “So we are seeing worse extremes on both sides,” said Van Dijk.

In southern China from May to July, the Yangtze and Pearl rivers flooded cities and towns, displacing tens of thousands of people and causing hundreds of millions of dollars of damage to crops. The river floods in Bangladesh in August after heavy monsoon rains affected almost 6 million people and destroyed at least a million tonnes of rice.

Meanwhile, in Spain in October more than 500mm of rain fell in eight hours, causing deadly flash floods. The city of Porto Alegre, Brazil, was inundated with two months’ worth of rain in just three days in May, transforming roads into rivers.

“Heavy rainfall events also caused widespread flash flooding in Afghanistan and Pakistan, killing more than 1,000 people,” Van Dijk said. The flooding also displaced 1.5 million people.

In the Amazon, drought struck. “Wildfires driven by the hot and dry weather burned through more than 52,000 sq km in September alone, releasing vast amounts of greenhouse gases,” Van Dijk said. “From historic droughts to catastrophic floods, these extreme events impact lives, livelihoods, and entire ecosystems.”

The researchers said seasonal climate forecasts for 2025 and current conditions suggested droughts could worsen in northern South America, southern Africa, and parts of Asia. Wetter regions such as the Sahel and Europe may face elevated flood risks.

“We need to prepare and adapt to inevitably more severe extreme events,” said Van Dijk. “That can mean stronger flood defences, developing more drought-resilient food production and water supplies, and better early warning systems. Water is our most critical resource, and its extremes – both floods and droughts – are among the greatest threats we face.”

Source: The Guardian

Reinventing the Waterwheel

In the foothills of the Himalayas, a group of villagers hauled a sturdy metal waterwheel into place. Its horizontal blades soon caught the rushing water of the stream directly below it. The machine began to spin, and electricity began to flow.

A waterwheel installed in rural Nepal. Photograph: Michael Erhart

The roughly 2-metre-tall waterwheel, installed in a village in Kashmir, India, was the result of years of design work and development by researchers at the Technical University of Munich (TUM) and partners.

“You have this continuous power flow,” said Michael Erhart, the chair of renewable and sustainable energy systems at TUM. “It’s not intermittent like the radiation of the sun or wind power.”

Waterwheels have been around for thousands of years. Formerly used to drive mechanical processes such as milling or hammering, they were a crucial component in the industrial revolution. Today, waterwheels connected to generators can produce zero-carbon electricity as they spin.

An Archimedes screw-style waterwheel was installed along the River Wandle in London in 2012. The 8.5kW system generates enough electricity to power 18 homes.

Some experts argue that greater adoption of electricity-generating waterwheels could help to decarbonise energy systems. For the Kashmiri villagers, their new waterwheel offered energy independence. It was installed alongside other renewable energy resources, including a microgrid, between 2022 and 2024.

Erhart’s colleagues had previously supported the deployment of a similar waterwheel in Nepal, as well as a demonstration prototype in Tegernsee, southern Germany.

The waterwheel in Tegernsee. Photograph: Michael Erhart

Before the new waterwheel arrived, the community in Kashmir had to rely on a centralised electricity grid that often let them down. “They had power cuts of weeks or even months,” said Erhart. The renewable energy kit meant the village could now survive off-grid.

The climate crisis and bouts of extreme weather are putting additional strain on power grids in India and Nepal. Decentralised microgrids connected to a mix of renewables including solar and waterwheel devices could, in theory, help remote communities to become energy self-sufficient.

The generating capacity of such wheels ranges from about 300W to 1kW, according to Erhart, depending on the flow of water. During flooding, it is possible to set up the wheel so that torrents of water can bypass it, meaning electricity generation may continue uninterrupted.

Erhart’s instructions for building the waterwheel are freely available online. The cost of assembling one could come to as little as $1,000 (£819), he estimated.

Separately, another kind of electricity-generating waterwheel was set up in Northern Ireland recently. The historic waterwheel attached to an old mill in Co Fermanagh was fully restored and now provides electricity to a restaurant within the building.

The Tully Mill restaurant’s waterwheel outputs roughly 1.5kW, according to Patrick Drumm, group treasurer of the Killesher Community Development Association. The wheel powers about 10 strong outdoor lights at the restaurant, though Drumm added that the cost of installing the system was significant at about £49,000. The project was made possible thanks to funding from the National Lottery.

It would be advantageous to use waterwheels even more widely, said Gerald Müller at the University of Southampton. Müller said a handful of companies in Germany currently restore or build waterwheels for electricity generation. “I was talking to the owner of one [of those companies] the other day and he was saying his books are pretty much full for the next three years – interest has increased because of the rise in electricity prices,” he added.

Müller’s research indicates that the efficiency of waterwheels, in terms of converting water power into electricity, can be as high as about 85%, .

One possible downside of waterwheels is the risk they might pose to aquatic life. However, research indicates they have a minimal impact on fish, for example.

Müller said that besides supplying private homes and buildings such as restaurants or hotels, waterwheels could also power pumps designed to move water up hills and irrigate fields on mountainsides.

Source: The Guardian

Weak consumer confidence slows solar adoption

Many households are interested in adopting rooftop solar power systems, but concerns about provider trustworthiness and high costs hinder their adoption, according to a study from Ateneo de Manila University.

Homeowners recognize that solar energy contributes to environmental protection by reducing greenhouse gas emissions and air pollution, helping combat the effects of climate change, according to a study by Department of Economics Professor Rosalina Palanca-Tan, published in the journal Challenges in Sustainability.

In a survey of 143 respondents, 82% expressed some interest in adopting solar panels, but only 20% had firm intentions to do so.

Despite the economic and environmental benefits, respondents were reluctant to invest due to the upfront cost needed for installation.

According to the study, a home rooftop solar power setup costs approximately $1,700 (₱100,000), equivalent to more than half a year’s salary for minimum wage workers.

“Many households are unsure if this initial expense is justified by long-term financial and environmental returns,” it said.

The survey found that, aside from costs, trustworthiness of providers, clarity on warranties, and perceived installation quality were equally important considerations.

The study found that while most respondents understood renewable energy’s role in combating climate change, few knew the specific benefits of rooftop solar power or how to find reliable installation services.

“Thus, the study urges stronger government intervention and public education campaigns. In particular, the study suggests improving net metering rates, expanding access to financing options, and accrediting trustworthy RTSP (rooftop solar power) providers to build consumer confidence,” the study said.

Source: Business World