Warning against impending climate catastrophe, the United Nations has said that four key climate change indicators— Greenhouse gas concentrations, sea level rise, ocean heat and ocean acidification—all set record highs in 2021.

A report&nbsp;released by the UN’s World Meteorological Organization&nbsp;said these extreme climate changes caused hundreds of billions of dollars in economic losses.

“It wreaked a heavy toll on human lives and well-being and triggered shocks for food and water security and displacement that have accentuated in 2022,” the WMO said in its report State of the Global Climate in 2021.

“This is yet another clear sign that human activities are causing planetary-scale changes on land, in the ocean, and in the atmosphere, with harmful and long-lasting ramifications for sustainable development and ecosystems," it said.

The UN agency said that in 2021, the levels of climate-warming carbon dioxide and methane in the atmosphere surpassed previous records.

The report also confirmed that the past seven years were the top seven hottest years on record.

The global annual mean temperature difference is considered from pre-industrial conditions (1850-1900) for six global temperature data sets (1850-2021).

The report confirmed that put of those seven warm years on record, the year 2021 was "only" because of a La Nina event (ocean phenomenon in the Pacifics) at the start and end of the year.

"This had a temporary cooling effect but did not reverse the overall trend of rising temperatures. The average global temperature in 2021 was about 1.11 (plus/minus 0.13) degrees Celsius above the pre-industrial level.

It is just a matter of time before we see another warmest year on record," said WMO Secretary-General Professor Petteri Taalas.

(With inputs from agencies)

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Warning against impending climate catastrophe, the United Nations has said that four key climate change indicators— Greenhouse gas concentrations, sea level rise, ocean heat and ocean acidification—all set record highs in 2021.

Warning against impending climate catastrophe, the United Nations has said that four key climate change indicators— Greenhouse gas concentrations, sea level rise, ocean heat and ocean acidification—all set record highs in 2021. A report released by the UN’s World Meteorological Organization said these extreme climate changes caused hundreds of billions of dollars in economic losses. “It wreaked a heavy toll on human lives and well-being and triggered shocks for food and water security and displacement that have accentuated in 2022,” the WMO said in its report State of the Global Climate in 2021. “This is yet another clear sign that human activities are causing planetary-scale changes on land, in the ocean, and in the atmosphere, with harmful and long-lasting ramifications for sustainable development and ecosystems," it said. The UN agency said that in 2021, the levels of climate-warming carbon dioxide and methane in the atmosphere surpassed previous records. The report also confirmed that the past seven years were the top seven hottest years on record. The global annual mean temperature difference is considered from pre-industrial conditions (1850-1900) for six global temperature data sets (1850-2021). The report confirmed that put of those seven warm years on record, the year 2021 was "only" because of a La Nina event (ocean phenomenon in the Pacifics) at the start and end of the year. "This had a temporary cooling effect but did not reverse the overall trend of rising temperatures. The average global temperature in 2021 was about 1.11 (plus/minus 0.13) degrees Celsius above the pre-industrial level. It is just a matter of time before we see another warmest year on record," said WMO Secretary-General Professor Petteri Taalas. (With inputs from agencies) WATCH WION LIVE HERE

Greenhouse gas, sea level all broke records in 2021, says UN, warns of 'climate catastrophe'

Invisible to people but deadly to marine life, ocean heatwaves have damaged ecosystems across the globe and are poised to become even more destructive, according to the first study to measure worldwide impacts with a single yardstick.

The number of marine heatwave days has increased by more than 50 per cent since the mid-20th century, researchers reported in the journal Nature Climate Change.

"Globally, marine heatwaves are becoming more frequent and prolonged, and record-breaking events have been observed in most ocean basins in the past decade," said lead author Dan Smale, a researcher at the Marine Biological Association in Plymouth, Britain.

Above the ocean watermark, on Earth's surface, 18 of the last 19 years have been the warmest on record, leading to more severe storms, droughts, heatwaves and flooding.&nbsp;

"Just as atmospheric heatwaves can destroy crops, forests and animal populations, marine heatwaves can devastate ocean ecosystems," Smale told AFP.

Compared to hot spells over land, which have claimed tens of thousands of lives since the start of the century, ocean heatwaves have received scant scientific attention.

But sustained spikes in sea-surface temperatures can also have devastating consequences.

A 10-week marine heatwave near western Australia in 2011, for example, shattered an entire ecosystem and permanently pushed commercial fish species into colder waters.

Corals have been the marquee victims of shallow-water heatwaves, and face a bleak future. Even if humanity manages to cap global warming at 1.5 degrees Celsius -- mission impossible, according to some scientists -- up to 90 per cent of corals are likely to die, the UN's top climate science body said in October.

But other bedrock species have suffered too: the 2011 surge of heat killed off large swathes of seagrass meadows and kelp forests, along with the finfish and abalone that depend on them.

Heat sponge

Another ocean hot spell off the coast of California warmed waters by 6 C (10.8 F) and lasted for more than a year.&nbsp;

Known as "The Blob", it generated toxic algae blooms, caused the closure of crab fisheries, and led to the death of sea lions, whales and sea birds.

More frequent and intense ocean heatwaves also have a direct impact on people by reducing fisheries harvests and adding to global warming, the researchers noted.

"Species of fish and crustaceans targeted for human consumption may be locally wiped out," Smale said.

"And carbon stored by seagrasses and mangroves may be released if they are hit by extreme temperatures."

To determine the full extent of marine heatwave impacts across different oceans, Smale and an international team from 19 research centres crunched data from more than 1,000 field studies that reported on how organisms and ecosystem responded. &nbsp;

By definition, marine heatwaves last at least five days. Seawater temperatures for a given location are "extremely high" -- the top 5-to-10 per cent on record for that time and place. &nbsp;&nbsp;

"Marine heatwaves can penetrate to hundreds of metres, though for our analysis we used data which only captures warming at the surface," Smale said.

As manmade global warming heats the planet, oceans have absorbed some 90 per cent of the extra heat generated.&nbsp;

Without that heat sponge, air temperatures would be intolerably higher.

Even if humanity does manage to cap global warming at "well below" 2C (3.6 F), as called for in the Paris climate treaty, marine heatwaves will sharply increase in frequency, intensity and duration, earlier research has shown.

Invisible to people but deadly to marine life, ocean heatwaves have damaged ecosystems across the globe and are poised to become even more destructive, according to the first study to measure worldwide impacts with a single yardstick.

Invisible to people but deadly to marine life, ocean heatwaves have damaged ecosystems across the globe and are poised to become even more destructive, according to the first study to measure worldwide impacts with a single yardstick. The number of marine heatwave days has increased by more than 50 per cent since the mid-20th century, researchers reported in the journal Nature Climate Change. "Globally, marine heatwaves are becoming more frequent and prolonged, and record-breaking events have been observed in most ocean basins in the past decade," said lead author Dan Smale, a researcher at the Marine Biological Association in Plymouth, Britain. Above the ocean watermark, on Earth's surface, 18 of the last 19 years have been the warmest on record, leading to more severe storms, droughts, heatwaves and flooding. "Just as atmospheric heatwaves can destroy crops, forests and animal populations, marine heatwaves can devastate ocean ecosystems," Smale told AFP. Compared to hot spells over land, which have claimed tens of thousands of lives since the start of the century, ocean heatwaves have received scant scientific attention. But sustained spikes in sea-surface temperatures can also have devastating consequences. A 10-week marine heatwave near western Australia in 2011, for example, shattered an entire ecosystem and permanently pushed commercial fish species into colder waters. Corals have been the marquee victims of shallow-water heatwaves, and face a bleak future. Even if humanity manages to cap global warming at 1.5 degrees Celsius -- mission impossible, according to some scientists -- up to 90 per cent of corals are likely to die, the UN's top climate science body said in October. But other bedrock species have suffered too: the 2011 surge of heat killed off large swathes of seagrass meadows and kelp forests, along with the finfish and abalone that depend on them. Heat sponge Another ocean hot spell off the coast of California warmed waters by 6 C (10.8 F) and lasted for more than a year. Known as "The Blob", it generated toxic algae blooms, caused the closure of crab fisheries, and led to the death of sea lions, whales and sea birds. More frequent and intense ocean heatwaves also have a direct impact on people by reducing fisheries harvests and adding to global warming, the researchers noted. "Species of fish and crustaceans targeted for human consumption may be locally wiped out," Smale said. "And carbon stored by seagrasses and mangroves may be released if they are hit by extreme temperatures." To determine the full extent of marine heatwave impacts across different oceans, Smale and an international team from 19 research centres crunched data from more than 1,000 field studies that reported on how organisms and ecosystem responded. By definition, marine heatwaves last at least five days. Seawater temperatures for a given location are "extremely high" -- the top 5-to-10 per cent on record for that time and place. "Marine heatwaves can penetrate to hundreds of metres, though for our analysis we used data which only captures warming at the surface," Smale said. As manmade global warming heats the planet, oceans have absorbed some 90 per cent of the extra heat generated. Without that heat sponge, air temperatures would be intolerably higher. Even if humanity does manage to cap global warming at "well below" 2C (3.6 F), as called for in the Paris climate treaty, marine heatwaves will sharply increase in frequency, intensity and duration, earlier research has shown.

Ocean heatwaves devastate wildlife, worse to come

ocean-heatwave

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