分类： environment

As record-breaking heat waves sweep across nearly every continent amid accelerating global warming, air conditioning has emerged as a critical life-saving technology — but it also carries a steep environmental cost that deepens the climate crisis it helps people survive, leading climate and public health experts warn. A new peer-reviewed study published in *Nature Health* on Monday quantifies both the life-saving benefits and growing climate risks of widespread cooling use, offering a data-backed look at this urgent global dilemma.

Led by senior author Kai Chen, an epidemiology professor at the Yale School of Public Health, the research analyzed more than 30 million U.S. death records collected between 2010 and 2020, pairing county-level data on dangerous heat exposure with mortality outcomes to calculate air conditioning’s impact. The study found that cooling systems saved an average of 5,267 American lives each year over the 11-year period, with a total of nearly 58,000 lives saved across the decade. The largest number of lives saved were recorded in warm southern U.S. states including Arizona, Florida, Texas, Louisiana, Alabama and Mississippi, while northern states from Washington to Maine saw fewer than 10 lives saved annually due to less frequent extreme heat.

United Nations officials estimate that extreme heat kills roughly half a million people globally each year, and demand for cooling is skyrocketing as average global temperatures climb. Data from the U.S. Energy Information Administration shows the number of “cooling degree days” — a metric measuring how much energy is required to cool indoor spaces during hot weather — has risen 28% in the U.S. since 1990, with 2024 setting an all-time record and 2026 on pace to exceed that mark. Across Europe, cooling degree days have more than doubled since 1990, pushing air conditioning adoption up 44%. The trend is even starker in other major warm regions: cooling use has tripled in India and more than doubled across Southeast Asia, according to the International Energy Agency (IEA). The IEA and United Nations Environment Programme (UNEP) project global electricity demand from cooling will triple by mid-century.

This growing demand creates a dangerous feedback loop, experts explain: roughly 90% of the electricity powering today’s air conditioning systems comes from burning fossil fuels, which release heat-trapping greenhouse gases that warm the planet further. The UN projects that greenhouse gas emissions from air conditioning will jump from 4.5 billion metric tons annually to 7.2 billion metric tons over the next 25 years — an amount nearly equal to the total current carbon emissions of the United States and European Union combined.

“Everyone knows air conditioning works, but from a climate change perspective, it is not an ideal solution,” Chen explained. “It leads to more carbon emissions … then it accelerates the climate warming problem.” Beyond greenhouse gas emissions, cooling systems also amplify the urban heat island effect by expelling waste heat directly into outdoor city environments, and increased power demand worsens conventional soot and smog air pollution that harms public health.

Chen’s study also highlights widespread overuse of cooling in many developed regions, particularly in commercial buildings. Chen noted that many office spaces are cooled to such low temperatures that workers often wear sweaters even during the hottest summer months, and more than half of the cooling use examined in the study qualified as unnecessary overconsumption. The research confirms that excess cooling beyond a reasonable threshold does not save additional lives, but only increases carbon emissions and accelerates climate change. Chen recommends setting indoor cooling temperatures no lower than 75 degrees Fahrenheit (24 degrees Celsius) as a reasonable balance between comfort and sustainability.

A 2020s global energy crunch, exacerbated by geopolitical conflict, has already pushed multiple nations to implement cooling regulations to cut energy use and emissions. Eight countries including Bangladesh, Cambodia, Jordan, Malaysia, the Philippines, the Seychelles, Singapore and Sri Lanka have enforced maximum cooling limits for office air conditioning, and some have even mandated full cooling shutdowns one day per week in public buildings. India proposed similar national cooling limits in 2025.

The issue also carries profound equity implications, experts emphasize: many of the world’s most vulnerable low-income communities lack consistent access to affordable air conditioning, even as they face the worst impacts of rising heat. UNEP’s chief heat officer Eleni Myrivili notes that in recent extreme heat waves, many low-income families have been forced to choose between paying for life-saving medication and running their cooling systems. “In a warming world, thermal comfort should not be a luxury,” Myrivili said. “It’s becoming a prerequisite for health, dignity and increasingly survival.”

Global policymakers and experts from 75 countries and 250 cities are now working to navigate this tightrope: expanding access to life-saving cooling for vulnerable communities without worsening climate change. Delegates will gather in Singapore this September for the Global Cooling Pledge conference to coordinate collaborative action on sustainable cooling solutions.

Experts point to comprehensive policy approaches that combine passive cooling strategies and energy-efficient technology to cut emissions while expanding access. UNEP cooling unit head Lily Riahi highlighted Singapore as a leading model for integrated cooling action. The city-state has implemented a sweeping national strategy that combines passive cooling measures such as expanded urban greenery, which reduces ambient urban temperatures and cuts annual energy costs by an estimated $35 million, with mandatory energy-efficiency standards for cooling and ventilation systems in both new and existing buildings. The approach has lowered local outdoor temperatures by up to 8 degrees Celsius (14 degrees Fahrenheit) in some areas, Riahi said.

Riahi noted that passive, nature-based solutions are sufficient for many mild heat conditions, but extreme, humid heat events still require active air conditioning to protect public health. Experts emphasize the ultimate solution will require shifting cooling energy demand to renewable energy sources and rolling out highly efficient cooling technology to break the link between increased cooling access and rising carbon emissions. The goal, Riahi said, is not less cooling overall, but “smarter and more equitable cooling” that protects both human life and the global climate.

In the flood-scorched hills of central Nepal’s Dhading district, crews are currently digging through layers of thick sludge to reach a submerged hydropower plant, a critical energy facility that keeps the lights on for more than 20,000 local residents. As workers clear debris from equipment buried when last week’s devastating flood surged off the mountains, disaster and climate experts are pushing for a fundamental shift: instead of simply rebuilding the facility in the same vulnerable riverside spot that led to its destruction, Nepal must prioritize long-term climate resilience when reconstructing its damaged infrastructure. The scale of the devastation stretches far beyond this single power station. Across Nepal, catastrophic floodwaters and landslides have left as many as 900 workers missing from a dozen active and under-construction hydropower projects, the Independent Power Producers’ Association Nepal reports, with hundreds of those workers believed to be trapped inside project tunnels. Combined, the disaster has claimed more than 900 lives across Nepal and southern China, with another 4,700 people still unaccounted for. For Nepal’s energy sector alone, the damage has taken an estimated 700 megawatts of generation capacity offline – roughly 10 percent of the country’s total available power. Beyond energy infrastructure, tens of kilometers of roads, dozens of bridges, and hundreds of critical public facilities including schools and hospitals have been destroyed or heavily damaged. As Nepal’s government shifts from immediate rescue and response to long-term recovery planning, experts say the top priority must be avoiding the mistakes that left the country so exposed to this disaster. “Authorities have to take a hard look in the mirror now and ask how they will be rebuilding in these places. They will also have to take a close look at other projects in Nepal that have not been built yet, whether they’ll be approved after this event,” said Jakob Steiner, a geoscientist from the University of Graz in Austria currently based in Dhaka, Bangladesh. Hydropower projects across the worst-hit districts of Rasuwa, Nuwakot, and Dhading have been fully or partially destroyed, a blow that hits particularly hard because hydropower forms the backbone of Nepal’s national electricity grid, serves as a core driver of economic growth, and generates critical export revenue for the low-income Himalayan nation. Most of Nepal’s untapped hydropower potential falls into the run-of-river category, meaning facilities are built directly alongside steep, narrow river corridors where land is scarce and flood and landslide risks can escalate in a matter of minutes. Many workers who are now missing took shelter in the projects’ large access and water diversion tunnels – structures big enough to accommodate full-sized trucks – when the flood hit, but have been unable to escape as debris blocked exit routes. Experts are calling for a complete rethinking of how Nepal plans its infrastructure, arguing that reconstruction should not just replace destroyed assets, but build systems that can absorb and recover from future climate-driven disasters. Ramraj Narasimhan, senior director at the Coalition for Disaster Resilient Infrastructure, says the goal should not be to make every single structure completely indestructible, but rather to build redundancy into critical systems to keep essential services running even when damage occurs. “If it gets damaged, let it get damaged, but can we build in redundancy in the system?” Narasimhan explained. That approach can mean a range of adjustments from selecting safer construction sites away from high-hazard river bends and unstable slopes, to adding alternate transportation routes, backup power generation, improved early warning systems, and risk-mitigation tools like disaster insurance to speed up recovery after an event. Risk assessments must also account for how a single infrastructure failure can cut off access for multiple isolated mountain communities, experts say. These changes are long overdue: the Coalition for Disaster Resilient Infrastructure estimates that $124 billion worth of Nepal’s existing infrastructure is exposed to climate-driven disasters, leading to an average of nearly $760 million in annual disaster losses. The country’s national disaster response fund, however, holds only a tiny fraction of that amount, leaving it ill-equipped to handle major catastrophic events like the recent flood. Climate scientists warn that risks across the Himalayan region are growing faster than almost anywhere else on Earth, driven by human-caused global warming. Glaciers across the Hindu Kush Himalaya are losing ice at an accelerating rate, while permafrost degradation, unstable mountain slopes, growing glacial lake outburst risks, and increasingly erratic monsoon rainfall are all combining to raise the frequency and severity of catastrophic floods, landslides, and debris flows, according to the International Center for Integrated Mountain Development, a Kathmandu-based climate research organization. For extreme events as large as the recent flood, even the most robust physical flood defenses are often overwhelmed, making early warning systems the most critical tool to protect human life, Steiner noted. In this case, the flood was detected at the China-Nepal border soon after it formed, but it moved so rapidly downriver that communities and workers upstream had little to no warning. There was, however, a gap of time between detection and the flood reaching downstream hydropower sites, raising urgent questions about why warnings were not issued faster to alert workers at risk. The disaster is expected to spark heightened scrutiny of future hydropower project approvals, with advocates calling for more rigorous, site-specific environmental, social, and disaster risk assessments, paired with stronger land-use regulations and accountability for project developers. Himanshu Thakkar, coordinator of the South Asia Network on Dams, Rivers and People, warns that large hydropower infrastructure can itself worsen downstream damage, acting as a “force multiplier” for disaster when large structures, construction debris, and altered river channels amplify the force of floodwaters. Thakkar argues that Nepal should diversify its energy mix to include more decentralized solar power generation, which carries far lower climate risk in the mountainous Himalayan landscape. As Nepal begins the long process of recovery, the question facing the country is not just how fast it can rebuild what was lost – but whether it will choose to rebuild those assets in harm’s way, ahead of the next inevitable climate-driven flood.

Indonesia’s Mount Sinabung, one of the country’s more than 120 active volcanoes, erupted on Monday, sending a massive 3,500-meter column of dark ash and thick smoke billowing into the sky above the Indonesian island of Sumatra.

In the immediate hours after the eruption, authorities reported no fatalities, injuries, mandatory mass evacuations, or disruptions to commercial air travel in the surrounding region. Despite the lack of early harm, disaster management officials issued urgent warnings, ordering residents, casual visitors and traveling tourists to avoid all activities in nearby Karo district villages, as well as any area within a 6-kilometer radius of the volcano’s 2,460-meter summit.

Gray volcanic ash has blanketed roads, parked vehicles, and residential and public buildings across multiple affected villages in Karo, leaving local infrastructure and communities coated in fine grit. In response, local disaster response teams have distributed free protective face masks to local residents to help prevent respiratory irritation from ash inhalation.

Following the eruption, Indonesia’s Geological Agency raised the official volcanic activity alert level for Mount Sinabung to “Watch,” the second-highest warning tier in the country’s volcanic monitoring system. The alert upgrade also came with an expansion of the marked safe zone surrounding the peak, extending the exclusion area for civilian activity.

In an official public statement released Monday, Lana Saria, head of the Indonesian Geological Agency, described this week’s eruption as an initial explosive event, warning that far larger, more hazardous eruptions could follow in the coming days or weeks.

The Geological Agency first detected signs of accelerating volcanic activity at Mount Sinabung in mid-August, when monitoring equipment recorded dozens of tectonic earthquakes around the peak and observed visible changes in volcanic activity. Even before Monday’s eruption, officials had already expanded the recommended exclusion radius to restrict non-essential public access to the area.

Over the past decade of repeated volcanic activity at Mount Sinabung, nearly 30,000 local residents have been permanently displaced from their homes surrounding the volcano, forced to resettle in safer areas outside the high-risk zone.

Indonesia, a sprawling archipelago nation home to more than 280 million people, sits along the Pacific “Ring of Fire,” a geologically active belt of volcanoes and tectonic fault lines that wraps around the entire Pacific Basin. This location makes the country extremely prone to frequent seismic and volcanic events, with dozens of active peaks monitored constantly for signs of dangerous activity.

ULAANBAATAR, Mongolia — After 12 days of intensive negotiations, delegates from nearly 200 nations concluded the United Nations Convention to Combat Desertification (UNCCD) biennial summit Friday, leaving the Mongolian capital with landmark funding commitments for land restoration but without resolving a years-long deadlock over a proposed global legally binding drought pact.
The summit convened amid growing alarm over accelerating land degradation across the globe: UNCCD data confirms 40 percent of the world’s total land area is already degraded, a crisis that erodes soil fertility, disrupts water storage, and threatens the livelihoods of billions of people. Yasmine Fouad, executive secretary of the UNCCD, told reporters that drought, amplified by rising global temperatures, is spreading to regions once considered low-risk for dry conditions, growing more frequent, intense and prolonged than at any point in recorded history.
Experts at the conference emphasized a underrecognized link between land health and drought resilience: unlike the common framing of drought as purely a product of insufficient rainfall, modern research shows pre-existing land degradation drastically worsens dry period impacts. Healthy, well-managed soil acts as a natural water reservoir, absorbing and retaining moisture to sustain crops, grasslands and ecosystems through extended dry spells. Degraded soils, by contrast, shed water rapidly, lose agricultural productivity, and leave communities far more vulnerable to erratic rainfall and rising temperatures. This interconnectedness means water management cannot be separated from land health, Fouad noted, arguing that sustainable water systems depend entirely on healthy, productive soils.
This interconnectedness is particularly critical for global food security, said Joao Campari, global leader for food and agriculture at WWF International. Treating land and water as separate policy issues ignores the basic requirements for stable food production, Campari explained: without access to both healthy land and reliable water, agricultural systems cannot function. The pressure on global land resources is set to intensify dramatically in coming decades: UN projections show the world will need to produce 50 percent more food by 2050 than it did in 2012 to feed a growing population. But expanding agricultural production by clearing natural grasslands and savannas only worsens land degradation, releases stored carbon from soils into the atmosphere, and reduces landscapes’ ability to store water. Land degradation also amplifies the frequency and severity of sand and dust storms, Fouad added: while these storms travel across continents through the air, their origins lie in unsustainable land management that leaves topsoil exposed. Restoring native vegetation and improving land management practices keeps soil anchored and reduces the intensity of these events.
Despite the deadlock on the drought agreement, the summit delivered tangible progress on funding for land restoration efforts. Delegates launched a new global rangelands initiative backed by $1.2 billion across 45 targeted projects, and the Asian Development Bank announced an additional $2 billion to combat land degradation across the Asia-Pacific region. Rangelands—which include grasslands, savannas, and other grazing lands that support pastoral communities—cover 54 percent of the Earth’s total land surface and sustain roughly 2 billion people globally. Campari warned that these ecosystems are being converted to other land uses at four times the rate of the world’s forests, and hold twice as much carbon in their soils as is currently present in the atmosphere. Clearing these lands for agricultural expansion releases massive volumes of greenhouse gases even when few trees are cut, he added, making their protection critical to both climate and food security goals.
Even with new pledges, global land restoration efforts face a massive annual funding gap. UN estimates show $355 billion in annual investment is required through 2030 to meet existing global land restoration commitments, but current annual investment totals only $77 billion, leaving a $278 billion shortfall. Private capital contributes just 6 percent of current global investment in land restoration, and most existing national drought plans lack the funding needed to turn early warning systems, sustainable water management and adaptive agriculture into on-the-ground action. While 70 countries now maintain national drought plans, up from just three in 2013, most remain unimplemented due to lack of resources. To address this gap, summit participants announced a new Drought Resilience Investment Facility, designed to mobilize up to $400 million in combined public and private capital for projects focused on water security, sustainable agriculture, nature-based solutions and land restoration.
Negotiators left Ulaanbaatar agreeing to defer a decision on the proposed legally binding global drought agreement until the next UNCCD summit, scheduled to take place in Egypt in two years—a delay that marks the second consecutive deferral of the decision. But many stakeholders rejected calls to wait for a formal global agreement to act. “We cannot wait for COP18 for solutions,” said Esther Penunia, secretary general of the Asian Farmers Association. “We know we have solutions and we can do them as long as we have the necessary resources.”
Fouad echoed that call, urging governments to shift from planning to investment, and to create inclusive national platforms that bring private companies, local communities, women and young people into the process of developing projects and attracting financing to address land degradation and drought resilience.
This reporting is part of AP’s ongoing global climate and environment coverage, which receives philanthropic funding from private foundations, with AP retaining full editorial control over all content.

Rescue teams continued digging through thick mud and debris across flood-ravaged terrain along the Nepal-China Himalayan border on Friday, even as disaster officials issued an urgent new warning: a dammed glacial lake formed by this week’s catastrophic event is growing and could overflow, triggering a second round of destructive flash flooding.

Nepalese authorities have ordered all security personnel, rescue workers, and local civilians involved in search and relief operations to remain on the highest alert, with standing instructions to evacuate immediately to higher ground if conditions deteriorate. Nepal Police spokesperson Abi Narayan Kafle confirmed to the Associated Press that rescue work has not been suspended, but operations are proceeding with extreme caution amid the fresh danger.

Satellite imagery analyzed by China’s state broadcaster CCTV places the newly formed lake in the exact same area as a glacial detachment that occurred on Wednesday, the initial event that set off a chain reaction of downstream destruction that left hundreds dead and more than 1,500 unaccounted for. The lake formed after glacial debris blocked the flow of an upstream river, and according to Nepal’s national disaster management authority, preliminary satellite assessments confirm the water body is expanding, raising the risk of a sudden barrier breach and catastrophic downstream flooding.

CCTV reports place the natural debris barrier holding the lake more than 10 kilometers from Gyirong Port, the key Nepal-China border crossing that was already completely submerged by mud and floodwater earlier this week. The lake sits at an elevation of 2,950 meters, roughly 1,000 meters above the already inundated border crossing.

Climate researchers tracking the fast-moving situation in the Himalayas explain that Wednesday’s ice-rock avalanche scattered massive amounts of rock and debris across river valleys, creating several small, unstable water bodies in its wake. “Another dammed lake was formed by the August 26th ice-rock avalanche and this has begun to outflow,” explained Qianggong Zhang, head of climate and environmental risks at the Kathmandu-based International Center for Integrated Mountain Development. Zhang noted the lake holds roughly a few million cubic meters of water — enough to fill around 1,200 Olympic-sized swimming pools — and sits in a valley segment with minimal elevation change between the lake and downstream population centers.

As the region grapples with the aftermath of the initial disaster, the threat of a second catastrophic event has sent urgent alarm through response teams. Climate and geoscience experts note that ongoing high temperatures are accelerating glacial melt across the region, leading to more water accumulation behind the unstable debris dam, which is already obstructing the natural flow of the river.

While both Zhang and Jakob Steiner, a Dhaka-based geoscientist from Austria’s University of Graz, emphasize that the current high alert must be taken seriously to protect rescue workers on the ground, they add that a second flash flood on the same scale as Wednesday’s deadly event is unlikely.

This reporting features contributions from Huizhong Wu in Bangkok, and is part of the Associated Press’ ongoing climate and environmental coverage, which receives philanthropic funding from private foundations. The AP maintains full editorial control over all content.

A newly formed natural lake, created by a recent massive landslide along the rugged Nepal-Tibet border, has triggered growing alarm among regional authorities and communities over the rising risk of a catastrophic secondary flood. In an on-site analysis of the unfolding situation, BBC correspondent Laura Bicker has broken down how this unexpected body of water is creating a dangerous hazard for downstream settlements.

The landslide, which occurred recently in the mountainous cross-border region, blocked a natural river channel, leading water to accumulate rapidly and form the new unstable lake. Geologists and disaster response teams warn that if the earthen dam created by the landslide gives way under the growing pressure of rising water, a sudden surge of floodwater could rush through downstream valleys, threatening homes, infrastructure, and the lives of thousands of people living in the area.

Local disaster management agencies have already stepped up monitoring of the lake’s water levels and are preparing emergency evacuation plans for at-risk communities, as climate experts note that changing weather patterns in the Himalayan region have increased the frequency of such landslide and flood events in recent years.