世界各地でサンゴの大規模な白化現象、記録的な暑さで悪化

【ワシントンＡＦＰ＝時事】オーストラリアから米フロリダ半島まで世界各地のサンゴ礁が、数か月にわたる記録的な暑さで白化が進み、危機にひんしている。米海洋大気局（ＮＯＡＡ）が１５日、衛星観測に基づき行っている熱ストレスモニタリングの結果を発表した。大規模な白化が発生するのは、ここ１０年で２度目。（写真は資料写真）
　ＮＯＡＡのデレク・マンゼロ氏は「世界の海の温暖化が進むにつれ、サンゴの白化はより頻繁に、より深刻になっている。深刻な白化現象が長引くとサンゴが死滅し、サンゴ礁に依存して暮らしている人々にも打撃を与える」と警告した。
　サンゴ礁の大規模な白化は、２０２３年初頭から米フロリダ半島、カリブ海、ブラジル、太平洋東部の熱帯、南太平洋、紅海、ペルシャ湾、オーストラリアのグレートバリアリーフなど世界各地で確認されている。
　■世紀末に絶滅？
　世界自然保護基金（ＷＷＦ）によると、仕事や食生活の他、暴風雨や浸食からの海岸線保護などでサンゴ礁に依存している。また。海洋生物の４分の１以上がサンゴ礁を住みかとしている。
　ＮＯＡＡは、世界のサンゴ礁の３０～５０％は既に失われており、大胆な介入を行わなければ、今世紀末にはサンゴ礁が完全に消滅する可能性もあると警告している。
　ＷＷＦのペペ・クラーク氏は「温暖化が１度進むごとに起きる危機を具体的、視覚的、現代的に示しているのがサンゴの白化だ。その規模と深刻さは、危険な気候変動が今まさに進んでいることを明確に示す証拠だ」と述べた。
　サンゴを取り巻く環境および今後の見通しは厳しいが、ＮＯＡＡはサンゴの白化に対する介入策が「大きく前進」していると説明する。そうした対策には、サンゴ苗をより深く冷たい場所へ移す、サンゴを保護するために日よけを設置するといったものが含まれる。【翻訳編集ＡＦＰＢＢＮｅｗｓ】
〔ＡＦＰ＝時事〕（2024/04/17-16:41）

The world is currently experiencing its second major coral bleaching event in 10 years, with reef systems from Australia to Florida teetering on the brink of disaster following months of record-breaking ocean heat, a US agency announced Monday.
The consequences of coral bleaching are far-reaching, affecting not only the health of oceans but also the livelihoods of people, food security, and local economies.
Severe or prolonged heat stress leads to corals dying off, but there is hope for recovery if temperatures drop and other stressors such as overfishing and pollution are reduced.
As the world's oceans continue to warm, coral bleaching is becoming more frequent and severe, said Derek Manzello of the US National Oceanic and Atmospheric Administration (NOAA).
When these events are sufficiently severe or prolonged, they can cause coral mortality, which hurts the people who depend on the coral reefs for their livelihoods.
NOAA's heat-stress monitoring is based on satellite measurements from 1985 to the present day. The current bleaching event is the fourth on record, with previous events in 1998, 2010 and 2016.
Coral -- which are marine invertebrates made up of individual animals called polyps -- have a symbiotic relationship with the algae that live inside their tissue and provide their primary source of food.
When the water is too warm, coral expel their algae and turn white, an effect called bleaching that leaves them exposed to disease and at risk of dying off.
- Unprecedented heat wave -
Since early 2023, mass bleaching of coral reefs has been confirmed throughout the tropics, including in Florida in the United States, the Caribbean, Brazil, and the eastern Tropical Pacific.
Florida's 2023 heat wave started earlier, lasted longer and was more severe than any previous event in that region ever recorded, said NOAA.
Australia's Great Barrier Reef, the largest coral reef system in the world and the only one visible from space, has also been severely impacted, as have wide swathes of the South Pacific, the Red Sea and the Gulf.
We know the biggest threat to coral reefs worldwide is climate change. The Great Barrier Reef is no exception, Australia's Environment Minister Tanya Plibersek said recently.
Often dubbed the world's largest living structure, the Great Barrier Reef is a 2,300 kilometer (1,400 mile) expanse of tropical corals that house a stunning array of biodiversity.
Repeated mass bleaching events have threatened to rob the tourist drawcard of its wonder, turning banks of once-vibrant corals into a sickly shade of white.
- End of century extinction? -
Roughly 850 million people worldwide rely on coral reefs for food, jobs and to protect coastlines from storms and erosion, according to the nonprofit WWF. The ecosystems provide a haven for ocean life, with over a quarter of marine species calling them home.
NOAA estimates the world has already lost 30 to 50 percent of its coral reefs already, and they could disappear entirely by the end of the century without significant intervention.
If we need a specific, visual, contemporary case of what's at stake with every fraction of a degree warming, this is it. The scale and severity of the mass coral bleaching is clear evidence of the harm climate change is having right now, said the WWF's Pepe Clarke.
Despite the grim outlook, NOAA said it had made significant strides in developing interventions against coral bleaching. These included moving coral nurseries to deeper, cooler waters and deploying sunshades to protect corals in other areas.