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Business Standard
an hour ago
- Science
- Business Standard
2023's marine heatwaves signal early irreversible coral damage: Study
Marine heatwaves -- prolonged periods of raised ocean temperatures than what are typical for that time of year -- experienced in 2023 were not only unprecedented, but may have also signalled a potential climate tipping point, with irreversible, negative impacts to coral reefs and ecosystems, according to a new study. Researchers from China and the US found that regions in oceans across the globe, including the North Atlantic, and the tropical, south and north Pacific experienced extreme marine heatwaves -- the longest in duration, widest in extent and highest in intensity on record. The findings, published in the journal Science, show that the most intense warming occurred in the North Atlantic, tropical eastern Pacific, north Pacific, and southwest Pacific, which "collectively accounted for 90 per cent of the global ocean warming". Heatwaves in the North Atlantic which began mid-2022 persisted for 525 days with an intensity four times the typical, making it "the longest recorded marine heatwave in the region", the authors said. The southwest Pacific heat event broke records for its expanse and prolonged duration, while unusual temperatures in the tropical eastern Pacific peaked at 1.63 degrees Celsius during the onset of El Nino, they said. 'El Nino' is the warm phase of the 'El Nino-Southern Oscillation' (ENSO) natural climate pattern, which involves changes in temperatures and atmospheric pressures in the Pacific Ocean. El Nino is linked with warmer ocean temperatures. The authors, including those from the US' Scripps Institution of Oceanography at the University of California, said the marine heatwaves of 2023 were "a global event with a 50-year return period, (with a less than two per cent chance of occurrence)". First author Tianyun Dong, a joint postdoctoral researcher at the Eastern Institute of Technology, Ningbo, and Southern University of Science and Technology in China, told PTI in an email, "Global warming, observed over a long-term and primarily driven by greenhouse gas emissions, has raised the ocean's baseline state, making marine heatwaves increasingly frequent and intense." Further, the trends observed also suggest a "possible indication of an approaching climatic tipping point", the study said. A climate tipping point, potentially a 'point of no return', is related with irreversible, disproportionate health and economic consequences for the world's most vulnerable, such as tropical coral reefs, and ice sheets of Greenland and Antarctica. "While a full (ocean-climate) system collapse has not occurred, irreversible impacts -- mass coral bleaching in tropical reefs, collapse of key habitats -- are already emerging," Dong said. Coral bleaching in reefs, or the loss of algae in reefs causing a 'whitening' and vulnerability to disease and death, are showing few signs of recovering, while the functional collapse of key habitats in some of the world's regions undermine biodiversity and the role of ecosystems, Dong explained. "These impacts reflect more than a short-term stress, suggesting a shift towards a permanent ecological change. The 2023 marine heatwaves may, therefore, mark a dangerous step closer to tipping points in the ocean-climate system," the first author said. Arpita Mondal, associate professor at the department of civil engineering and centre for climate studies, IIT Bombay, and not involved with the study, told PTI, "Based on a primary reading of the paper, I'm quite convinced of the scientific robustness." Mondal explained that the ocean and atmosphere "talk to each other through processes -- called the 'teleconnections' -- through which far-away processes can influence local weather". "For example, processes in the southern and equatorial Pacific Ocean can influence the Indian monsoon," she said. "Of course, El Nino is the most significant phenomenon which affects not only monsoons in South Asia, but ENSO-neutral conditions -- where neither El Nino nor La Nina dominate -- have been linked with the heat waves in the pre-monsoon season too," Mondal explained. "Similarly, oscillations and circulation of currents in oceans and atmosphere can impact weather worldwide," she added. The study team analysed satellite observations and temperature data of the world's oceans. Data from the NASA-funded 'ECCO2' project, focussed on producing a high-resolution estimate of the state of the world's oceans and sea ice, was also analysed. First author Dong said that despite a relatively weak El Nino -- studies show its growth rate unexpectedly decelerated in mid-2023 -- the unprecedented nature of 2023's marine heatwaves cannot be explained by natural climate variability alone. "A continued warming of the planet -- especially when combined with El Nino -- could produce even more extreme marine heatwaves, pointing toward a potential new normal of amplified ocean heat extremes and a higher chance of crossing physical and ecological tipping points," the first author said. Mondal, who is not involved in the study, pointed to the concerning lack of reliable, long-term ocean data. "My concern is more about the lack of long-term, reliable ocean data globally. We have only been monitoring oceans in the recent years. We do not have say, 150 to 200 years of ocean surface temperatures recorded. However, satellites developed in the last 50 years or so have definitely helped in complementing the buoys which have been in place for monitoring the ocean," she said.
Time of India
13-07-2025
- Climate
- Time of India
U'khand emerging as hotspot for extreme climate events: Study
Dehradun: A new scientific study published in the 'Journal of the Geological Society of India' has confirmed what many in Uttarakhand have long feared -- the state is fast becoming a hotspot for extreme weather events. The study flagged alarming trends in rainfall variability, surface runoff and rising temperatures, alongside a sharp spike in cloudbursts and flash floods, especially since 2010. Conducted by geoscientists from Doon University, Wadia Institute and Delhi University, the study -- published in the July issue -- analysed nearly four decades (1982-2020) of climate data using satellite-based models. The findings suggested that Uttarakhand is increasingly vulnerable to both monsoon and non-monsoon extreme weather, driven by a complex interplay of regional climatic shifts and global phenomena such as the El Nino-Southern Oscillation (ENSO), North Atlantic Oscillation (NAO) and the Indian Ocean Dipole. Researchers observed a distinct increase in extreme rainfall and surface runoff events post-2010. From 1998 to 2009, the state saw rising temperatures and unusually low rainfall -- a trend that coincided with weakened global climate oscillations. But after 2010, the pattern reversed, particularly in central and western Uttarakhand, accompanied by a surge in cloudbursts. "Analysing cloudburst and extreme rainfall events in Uttarakhand between 1970 and 2021 reveals a clear increase in frequency after 2010," said YP Sundriyal, professor at Doon University and lead author of the study. by Taboola by Taboola Sponsored Links Sponsored Links Promoted Links Promoted Links You May Like Is it legal? How to get Internet without paying a subscription? Techno Mag Learn More Undo The study examined 140 extreme hydro-meteorological events, most clustered between 30°-31°N latitude and 79°–80.5°E longitude -- a zone aligned with the Main Central Thrust (MCT), a major geological fault line. Rudraprayag and Bageshwar districts emerged as key hotspots, owing to the region's geological fragility and the influence of orographic lifting. While seasonal temperature variations were less erratic than rainfall, consistent warming was observed in the northern glaciated zones, especially in upper Rudraprayag and Bageshwar. These areas also showed increasing surface radiative temperature, which the researchers said may correlate with glacial retreat and heightened flood risk. Notably, the study challenged the prevailing assumption that extreme rainfall events in the region are primarily driven by positive ENSO or Indian Ocean Dipole phases. "The relationship is more nuanced than previously thought," the authors noted, suggesting that local moisture transport patterns and Himalayan topography may exert stronger influence on regional climate dynamics. The authors called for urgent district-level climate adaptation planning, better early warning systems and enhanced monitoring in high-risk zones, especially as Uttarakhand continues to face cascading climate challenges.
The Citizen
04-06-2025
- Climate
- The Citizen
Winter arrives with double cold fronts and chilly nights
Experts warn colder nights and frost are likely due to wet soil from recent rainfall. The first of the winter cold fronts moving over parts of the country is a preview of the rest of the season. Vox Weather meteorologist Annette Botha said it was officially winter in South Africa, although some argue winter only starts on 21 June. The first of two cold fronts moving in over the country with chilly temperatures are a taste of what's to come. Cold front a taste of what's to come 'A stronger, more intense cold front is set to hit on Saturday. On Friday it will be windy in the interior with gusting northwesterly winds ahead of the strong cold front expected to move over the Western Cape,' she said. Vox Weather meteorologist Michelle du Plessis said there was a difference between meteorological and astronomical seasons. 'Meteorological seasons are based on annual temperature cycle and follow the calendar, so every three months is a new season,' she said. ALSO READ: SA Weather forecasts cool and fine weather with rains and winds 'Astronomical seasons are based on the position of the earth relative to the sun and use solstices and equinoxes,' she added. Du Plessis said higher rainfall didn't necessarily mean lower temperatures in winter. 'Not necessarily colder overall – but wetter soils can play a role in how temperatures behave at night. Wetter soil from recent rainfall plays role in night temps 'When soils are wetter from good autumn rainfall, they to lose heat faster overnight, especially under clear skies. This can lead to colder nights and more frequent frost, even if daytime temperatures remain fairly mild. 'So while it doesn't mean we'll have a colder winter in general, the risk of frost can increase, particularly in inland regions like the Free State, Gauteng and the highveld, where frost is already common.' Du Plessis said after a wet summer or autumn, the soil holds onto more moisture going into winter. ALSO READ: The cold front is here! Here's how long it will last for [VIDEO] 'That doesn't mean the whole winter will be colder. Temperatures depend more on the weather systems that move over the country and whether we get bursts of cold, subpolar air, but it can make nights feel colder,' she said. Du Plessis said historical climate patterns from the SA Weather Service show frost can occur even in warmer-than-average winters, especially when skies are clear and soil moisture is high. This allows surface temperatures to drop rapidly at night. 'The latest seasonal models are showing above-average temperatures overall this winter. We'll still get those icy cold snaps like every year,' she said. Above-average temps overall this winter Last month, the SA Weather Service issued the seasonal climate watch from May to September. According to the seasonal forecast, the El Nino-Southern Oscillation has returned to a neutral state and will be in a neutral state for the foreseeable future. The southwestern and the southern and eastern coastal areas are expected to receive mostly below-normal rainfall early, midand late-winter. The minimum and maximum temperatures are expected to be above normal for most parts during the winter, with the exception of the southern coastal areas that are expected to be below normal in parts. NOW READ: Get your blankets out: Cold front to hit Gauteng
The Star
23-05-2025
- Climate
- The Star
INTERACTIVE: No extreme dry conditions expected despite hot 2024
Malaysian Meteorological Department assistant officer Norashikin Anuar monitoring weather conditions through satelite/radar images at Malaysian Meteorological Department, Petaling Jaya. — FAIHAN GHANI/The Star PETALING JAYA: Last year turned out to be the fourth hottest year on record for Malaysia, but no extreme dry conditions are expected this year, says the Malaysian Meteorological Department (MetMalaysia). Although Malaysia is currently experiencing more dry days than rainy days due to the South-West Monsoon, heavy rains with thunderstorms and strong winds may still occur occasionally. 'The majority of forecasts produced by the latest international weather models do not expect extreme dry weather phenomena to occur throughout this Southwest monsoon season,' said MetMalaysia director-general Dr Mohd Hisham Mohd Anip. Mohd Hisham said current ENSO (El Nino-Southern Oscillation) conditions, which affects global weather patterns, are neutral and are expected to remain so throughout the year. A neutral ENSO means the climate is neither in an El Nino nor a La Nina state, but is in a normal condition. El Nino is a climate pattern typically bringing hotter, drier weather to Malaysia, while La Nina usually causes wetter conditions. 'Therefore, the country is also expected to experience the inter-monsoon transition from late September to early November, along with the Northeast monsoon at the end of the year under normal conditions." Mohd Hisham said last year was the fourth hottest year observed since 1981, when MetMalaysia began tracking the country's annual average temperature. The average annual temperature for Malaysia in 2024 was 27.55°C. He said the warmest year was 2016 (27.84°C), followed by 1998 (27.7°C) and 2019 (27.63°C). He said that Chuping, Perlis, had the highest temperature recorded last year with the mercury rising to 39.0°C on March 23. Chuping also experienced 52 consecutive days without rain in 2024, marking it as the location with the longest dry spell in 2024. Mohd Hisham said that the country experienced 45 days under a Level 2 high temperature advisory last year, the highest for any year in the past decade. A Level 2 (Orange) advisory means that a location is officially facing a heatwave, with temperatures going above 37°C but remaining below 40°C. According to previous reports by The Star , MetMalaysia issued nearly 2,000 Level 1 and Level 2 high temperature alerts since 2023. Among the locations or areas most affected by extreme temperatures, Baling in Kedah emerged as the hottest spot, receiving the highest number of alerts at 73. This was followed by Padang Terap with 61 alerts and Pendang with 56 alerts.
Straits Times
08-05-2025
- Climate
- Straits Times
US CPC sees 74% chance of ENSO Neutral conditions through June-August
El Nino-Southern Oscillation (ENSO) neutral conditions are expected to be favored through the Northern Hemisphere in summer 2025 (74% chance during June-August), the United States' Climate Prediction Center said on Thursday. Chances of ENSO neutral conditions exceed 50% through August-October 2025, it added. WHY IT'S IMPORTANT La Niña is part of the El Niño-Southern Oscillation (ENSO) climatic cycle, which affects water temperatures in the central and eastern Pacific Ocean. La Niña results in cooler water temperatures, increasing the chances of floods and droughts, which can impact crops. When ENSO is neutral, water temperatures stay around the average level, leading to more stable weather and potentially better crop yields. CONTEXT The sugar production estimate for the ongoing 2024/25 season has been revised down to 28 million tons due to the adverse impacts of El Niño and limited groundwater resources for irrigation, a report issued on May 05 by the U.S. Department of Agriculture's Foreign Agricultural Service post in New Delhi showed. KEY QUOTES "Neutral ENSO really has no usual conditions associated with it as a neutral ENSO results in other conditions influencing the local and global pattern," AccuWeather's lead international forecaster Jason Nicholls said. "The pattern this spring has resulted in some dryness concerns in the UK and northern Europe while southern Europe has been wet. It looks like the pattern will change heading into summer with more rain opportunities in northern Europe which may improve crop prospects." REUTERS Join ST's Telegram channel and get the latest breaking news delivered to you.
