Reaching net zero carbon emissions before 2060 is critical to avoid this catastrophe
By Rohini Krishnamurthy
Published: Wednesday 15 February 2023
Over the past century, the global mean sea level has increased by about 20 centimetres. Representative photo: iStock.UN-mandated Paris Agreement’s target of limiting global temperature rise to 2 degrees celsius is probably insufficient to prevent an accelerated sea level rise over the next century, a new study warned.
If the global temperature rise is not kept below 1.8°C, the world could witness an “irreversible loss” of west Antarctic and Greenland ice sheets and a rapid sea level rise, the study published in Nature Communications highlighted.
Also read: Receding cryosphere: What latest WMO report warns us about
Greenland and the Antarctica ice sheet will each likely contribute about 60-70 centimetres to the global mean sea level rise over the next 130 years under a high emission scenario, the findings showed.
Reaching net zero carbon emissions before 2060 is critical to avoid this catastrophe.
“The west Antarctic and Greenland ice sheets play a crucial role in future sea level rise,” Axel Timmermann, co-author of the study and director of the IBS Center for Climate Physics, told Down To Earth.
Missing the 2060 goal could cause the ice sheet to disintegrate and melt at an accelerated pace, he explained. The average global temperature has increased by slightly more than 1°C since 1880, according to the United States National Aeronautics and Space Administration.
Watch video: Highest glacier on Mt Everest is rapidly melting
Over the past century, the global mean sea level has increased by about 20 centimetres. This could be partly attributed to the thermal expansion of seawater (increase in volume due to warming oceans), glacier and ice-sheet melt and changes in groundwater storage.
The latest climate model projections presented in the sixth assessment report of the Intergovernmental Panel on Climate Change have differing views on how quickly the major ice sheets will respond to global warming, according to the study.
The team highlighted that melting ice sheets, likely the largest contributor to sea level change, are the hardest to predict as the physics governing their behaviour is complicated.
Computer models do not consider the fact that ice sheet melting has an impact on ocean processes. This, in turn, can interact with the ice sheet and the atmosphere, Jun Young Park, a graduate student and one of the study’s authors, said.
Read more: What’s going on with the Greenland ice sheet?
“The response of ice sheets to future climate change depends on the atmosphere and ocean warming and these factors are partly determined by what the ice sheets do,” Timmermann explained.
Capturing the two-way coupling between the different components has been challenging, he added.
So, researchers from the Republic of Korea, the US and Australia used a model that captures the interactions between ice sheets, icebergs, the ocean and the atmosphere in both hemispheres.
Their simulations showed that ice sheets’ contributions to sea level may continue to speed up even if global surface temperatures increase at a reduced rate after 2100.
By 2150, global sea level rise is estimated to rise by roughly 1.4, 0.5 and 0.2 metres under high, mid and low-emission scenarios, respectively.
The increase could be avoided under a low greenhouse gas emission scenario, with temperatures staying below 1.5 °C.
“According to our simulations, limiting 21-century global surface temperature rise to 2 °C above the pre-industrial level would be insufficient to slow the global sea level rise rate over the next 130 years,” the researchers wrote in their study.
A 2022 study warned that changing water circulation linked to climate change is probably destabilising the east Antarctic ice sheet, which is about the size of the US. The findings also underscored the need to keep global temperature rise to 1.5°C.
UN chief says rising seas a ‘death sentence’ for some countries
UN secretary general warns that low-lying communities and entire countries could disappear under rising sea levels.
Published On 15 Feb 2023
United Nations Secretary-General Antonio Guterres has warned of the threat posed by rising sea levels to hundreds of millions of people living in low-lying coastal areas and small island states as new data reveals seas have risen rapidly since 1900.
In a stark address to the first UN Security Council debate on the implications of rising sea levels for international peace and security, Guterres said countries such as Bangladesh, China, India and the Netherlands were threatened as were big cities such as Bangkok, Buenos Aires, Jakarta, Lagos, London, Los Angeles, Mumbai, Maputo, New York and Shanghai.
“The danger is especially acute for nearly 900 million people who live in coastal zones at low elevations — that’s one out of 10 people on Earth,” he told the council on Tuesday.
Climate change is heating the planet and melting glaciers and ice sheets which, according to NASA, has resulted in Antarctica shedding some 150 billion tonnes of ice mass each year on average, Guterres said. Greenland’s ice cap is shrinking even faster and losing 270 billion tonnes per year.
“The global ocean has warmed faster over the past century than at any time in the past 11,000 years,” the UN chief said.
“Our world is hurtling past the 1.5-degree warming limit that a liveable future requires and, with present policies, is careening towards 2.8 degrees – a death sentence for vulnerable countries,” he said.
Developing countries, in particular, must have the resources to adapt to a rapidly changing world and that means ensuring the $100bn climate finance commitment to developing countries is delivered, Guterres said.
The UN chief offered examples of the effect of a warming planet and rising sea levels on communities and countries stretching from the Pacific to the Himalayan river basins.
Ice melting in the Himalayas has already worsened flooding in Pakistan, he said. But as the Himalayan glaciers recede in the coming decades, the mighty Indus, Ganges and Brahmaputra rivers will shrink. Hundreds of millions of people living in the river basins of the Himalayas will suffer the effects of both rising sea levels and the intrusion of saltwater, Guterres said.
“We see similar threats in the Mekong Delta and beyond. The consequences of all of this are unthinkable. Low-lying communities and entire countries could disappear forever,” he said.
“We would witness a mass exodus of entire populations on a biblical scale.”
With rising sea levels creating new arenas for conflict as competition for freshwater sources and land intensifies, the secretary general said the climate crisis needs to be addressed at its root cause: reducing emissions to limit warming. Understanding the link between insecurity and a changed climate also requires developing early-warning systems for natural disasters, and legal and human rights provisions are also needed, particularly to address the displacement of people and loss of territories.
“People’s human rights do not disappear because their homes do,” Guterres said.
The meeting of the Security Council heard speakers from some 75 countries all voicing concern about the effect of rising sea waters, the Associated Press reported.
Speaking on behalf of the Alliance of Small Island States, Samoa’s UN ambassador Fatumanava-o-Upolu III Pa’olelei Luteru said alliance members were among the lowest to emit the greenhouse gases that had caused global warming and climate change.
“Yet, we face some of the most severe consequences of rising sea levels,” Lutero said, according to AP.
“To expect small island states to shoulder the burden of sea level rise, without assistance from the international community will be the pinnacle of inequities,” he said.
Ambassador Amatlain Kabua of the Marshall Islands said many of the tools to address climate change and rising seas were already known.
“What is needed most is the political will to start the job, supported by a UN special representative” to spur global action, she said.
KEEP READING
Greenland already locked in to huge sea level rise: Study
SOURCE: AL JAZEERA
UN secretary general warns that low-lying communities and entire countries could disappear under rising sea levels.
A mother and daughter wade through water caused by rising sea levels and land subsidence north of Jakarta, Indonesia in 2020
[Willy Kurniawan/Reuters]
Published On 15 Feb 2023
United Nations Secretary-General Antonio Guterres has warned of the threat posed by rising sea levels to hundreds of millions of people living in low-lying coastal areas and small island states as new data reveals seas have risen rapidly since 1900.
In a stark address to the first UN Security Council debate on the implications of rising sea levels for international peace and security, Guterres said countries such as Bangladesh, China, India and the Netherlands were threatened as were big cities such as Bangkok, Buenos Aires, Jakarta, Lagos, London, Los Angeles, Mumbai, Maputo, New York and Shanghai.
“The danger is especially acute for nearly 900 million people who live in coastal zones at low elevations — that’s one out of 10 people on Earth,” he told the council on Tuesday.
Climate change is heating the planet and melting glaciers and ice sheets which, according to NASA, has resulted in Antarctica shedding some 150 billion tonnes of ice mass each year on average, Guterres said. Greenland’s ice cap is shrinking even faster and losing 270 billion tonnes per year.
“The global ocean has warmed faster over the past century than at any time in the past 11,000 years,” the UN chief said.
“Our world is hurtling past the 1.5-degree warming limit that a liveable future requires and, with present policies, is careening towards 2.8 degrees – a death sentence for vulnerable countries,” he said.
Developing countries, in particular, must have the resources to adapt to a rapidly changing world and that means ensuring the $100bn climate finance commitment to developing countries is delivered, Guterres said.
The UN chief offered examples of the effect of a warming planet and rising sea levels on communities and countries stretching from the Pacific to the Himalayan river basins.
Ice melting in the Himalayas has already worsened flooding in Pakistan, he said. But as the Himalayan glaciers recede in the coming decades, the mighty Indus, Ganges and Brahmaputra rivers will shrink. Hundreds of millions of people living in the river basins of the Himalayas will suffer the effects of both rising sea levels and the intrusion of saltwater, Guterres said.
“We see similar threats in the Mekong Delta and beyond. The consequences of all of this are unthinkable. Low-lying communities and entire countries could disappear forever,” he said.
“We would witness a mass exodus of entire populations on a biblical scale.”
With rising sea levels creating new arenas for conflict as competition for freshwater sources and land intensifies, the secretary general said the climate crisis needs to be addressed at its root cause: reducing emissions to limit warming. Understanding the link between insecurity and a changed climate also requires developing early-warning systems for natural disasters, and legal and human rights provisions are also needed, particularly to address the displacement of people and loss of territories.
“People’s human rights do not disappear because their homes do,” Guterres said.
The meeting of the Security Council heard speakers from some 75 countries all voicing concern about the effect of rising sea waters, the Associated Press reported.
Speaking on behalf of the Alliance of Small Island States, Samoa’s UN ambassador Fatumanava-o-Upolu III Pa’olelei Luteru said alliance members were among the lowest to emit the greenhouse gases that had caused global warming and climate change.
“Yet, we face some of the most severe consequences of rising sea levels,” Lutero said, according to AP.
“To expect small island states to shoulder the burden of sea level rise, without assistance from the international community will be the pinnacle of inequities,” he said.
Ambassador Amatlain Kabua of the Marshall Islands said many of the tools to address climate change and rising seas were already known.
“What is needed most is the political will to start the job, supported by a UN special representative” to spur global action, she said.
KEEP READING
Greenland already locked in to huge sea level rise: Study
SOURCE: AL JAZEERA
No comments:
Post a Comment