In Tonga, volcano-triggered tsunami underscores islands’ acute climate risk

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SINGAPORE, Jan 20 (Reuters) – For the South Pacific island nation of Tonga, the tsunami triggered by Saturday’s volcanic eruption has laid bare some of the ways climate change threatens the very existence of the islands.

By increasing temperatures and raising sea levels, climate change is likely to worsen disasters caused by tsunamis, storm surges and heat waves, experts say.

Recognizing this risk, Tonga has been a key voice representing climate-vulnerable nations, saying at the UN climate talks in November that global warming “beyond the 1.5C threshold would be a absolute disaster for Tonga” and other Pacific islands as they are subsumed. by the sea.

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Their plea for global climate action is particularly desperate, given that Pacific island nations account for just 0.03% of global carbon emissions, according to the World Bank.

“Although we are resilient and trying to adapt, it only takes a few extra meters of water to cover a house, to kill a child or a family,” said Shairana Ali, CEO of international charity Save the Children. , in neighboring Fiji.

RISE OF THE SEAS

Tonga reported that waves of up to 15 meters crashed into its outer islands after Saturday’s volcanic eruption, flattening homes and killing at least three people. The eruption triggered tsunami warnings across the Pacific. Read more

As sea levels continue to rise over the next few decades, tsunamis and storm surges will likely reach further inland with even greater risk of damage.

“Tsunami waves and storm surges are above sea level,” said Benjamin Horton, who has studied global sea level rise and is head of the Earth Observatory of Singapore. So with higher seas, “you won’t need such large natural disasters to cause widespread devastation.”

Sea levels around the archipelago nation of 105,000 people are rising about 6mm a year, almost double the global average rate, according to the United Nations’ Global Sea Level Observing System. This is because the islands lie in warmer waters near the equator, where sea level rise is more pronounced than at the poles.

The damage caused by tsunamis and storm surges does not end with the destruction by the waves. Seawater running ashore can foul agricultural soil and render it unusable for years. Tsunami waves also exacerbate coastal erosion and destroy natural buffers against rising seas, such as coral reefs and mangroves.

With climate change warming the surface of the ocean, such storm surges are more likely as warm water fuels increasingly powerful cyclones. Tonga and neighboring countries have been hit by two category five cyclones in the past four years, causing hundreds of millions of dollars in damage.

WARMER TEMPERATURES

Temperatures in Tonga are already rising, with the average daily temperature now 0.6°C warmer than it was in 1979. The frequency of hot days and hot nights has increased across the Pacific.

According to the UN’s Intergovernmental Panel on Climate Change, this continued warming is likely to dry out the soil, as high temperatures cause greater evaporation and affect regional rainfall patterns.

The country is likely to experience more heat waves in the coming decades, with temperatures frequently exceeding 35°C, according to the report. This extreme heat can be especially dangerous when combined with tropical humidity.

Sea waters are also warming, at a rate three times the global average, according to data from the World Meteorological Organization. And marine heat waves – which can kill fish and corals – are becoming more frequent, more intense and longer lasting across much of the Pacific Ocean.

Tonga itself saw a large mass of ocean heat forming southeast of its islands in January 2020, with surface water temperatures registering 6 degrees Celsius above average for that month.

REBUILD OR MOVE FORWARD?

Pacific islanders are expected to be among the first groups of global climate refugees as the effects of climate change push them to leave their homelands.

“Maybe it will come to this eventually. But I hope not,” said Josephine Latu-Sanft, a Tongan who now lives in London and works as a climate communicator. “People don’t want to move.

Tongans have already rebuilt their communities twice in recent years – after Cyclone Gita in 2018, and again after Cyclone Harold in 2020.

“Tongans are very resilient” and reluctant to leave the islands despite the risks, Latu-Sanft said. “We have lived there for centuries. Our roots and our identity are in the land and in the sea.”

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Reporting by Kanupriya Kapoor in Singapore and Gloria Dickie in London; Editing by Katy Daigle and Richard Pullin

Our standards: The Thomson Reuters Trust Principles.


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