Sea levels to rise 15 INCHES by 2100, NASA study warns

If greenhouse gas emissions continue at their current pace then the vast ice sheets of Greenland and Antarctica will continue to melt and could cause sea levels to surge by 15 inches (38 cm) by the end of the century, NASA warns.

An international project of more than 60 experts calculated how catastrophic the melting ice sheets of Greenland and Antarctica would be on the world’s oceans.

It revealed the vast ice sheet of Greenland could add up to 3.5 inches (8.9 cm) to the global sea level by 2100.

Meanwhile, Antarctica’s vast ice sheets have the potential to cause sea levels to surge by up to 12 inches (30 cm) by the end of the century.

An international project calculated how catastrophic the melting ice sheets of Greenland and Antarctica would be on the world’s oceans. Under current greenhouse gas emission levels, it could result in a sea level rise of more than 15 inches by 2100

This graphs shows the difference in surface temperature for Antarctica based on one computer model under a high emission scenario by 2100. The darker red indicates temperatures up to 8 Kelvin warmer than currently

Pictured, two maps showing the likely net loss of ice from Greenland under a low emissions (left) and high emissions (right) scenario by 2100. The darker the shade of blue, the more ice the ice sheet is predicted to lose

NASA’s Goddard Space Flight Center in Maryland spearheaded the project, called the Ice Sheet Model Intercomparison Project (ISMIP6).

The findings of the study align with previous findings published in last year’s landmark IPCC paper.

Data published in that report found Greenland would contribute 3.1 to 10.6 inches (8 to 27 cm) to global sea level rise between 2000-2100 and Antarctica could contribute 1.2 to 11 inches (3 to 28 cm).

It found sea levels rose globally by around 5.9 inches (15cm) during the 20th century, but are currently rising more than twice as fast, at 3.6 mm per year.

The findings of the study align with previous findings published in last year’s landmark IPCC report. Data published in that report found Greenland would contribute 3.1 to 10.6 inches (8 to 27 cm) to global sea level rise between 2000-2100 and Antarctica could contribute 1.2 to 11 inches (3 to 28 cm)

Greenland’s ice sheet melted more in 2019 than during any other year on record

Melting from Greenland’s ice sheet broke records last year — losing a total of 532 gigatonnes of mass overall, analysis of satellite data has revealed.

Experts led from Germany found that the ice loss in 2019 was 15 per cent higher than the previous worst year on record — which was 2012.

However, they also noted that favourable conditions in 2017–2018 meant that melting was lower than in any other two-year period between 2003–2019.

Researchers can assess how fast ice mass is lost by tracking changes in gravity as recorded by the Gravity Recovery and Climate Experiment (Grace) missions.

Melt from the Greenland Ice Sheet is one of the largest contributors to sea level rise and presently contributes an increase of around 0.03 inches (0.76 mm) annually.

In total, sea levels rose by around 0.14 inches (3.5 mm) each year from 2005 to 2017, researchers have calculated.

The findings come a week after a study revealed that Greenland’s glaciers have already passed what researchers have called the ‘point of no return’.

This, experts warned, means that the ice would now continue to melt away even if global warming could be completely stopped.

The new results, published this week in a special issue of the journal Cryosphere, help researchers to quantify how severe the melting of ice sheets may be.

‘One of the biggest uncertainties when it comes to how much sea level will rise in the future is how much the ice sheets will contribute,’ said project leader and ice scientist Sophie Nowicki, now at the University at Buffalo.

‘And how much the ice sheets contribute is really dependent on what the climate will do.’

Just like the IPCC report, the NASA team looked at a low and high emissions scenario.

For the Greenland ice sheet, this would lead to a global sea level rise of 1.3 inches (3cm) and 3.5 inches (9cm), respectively.

Antarctica is more complex as the west is shedding ice and contributing to sea level rise while the vast East Antarctic ice sheet can gain mass as warm temperatures increase snowfall.

As a result, anything could happen, with a best case scenario of the continent actually decreasing sea levels by 3.1 inches (7.8 cm).

However, the potential for devastating ice loss means it could also contribute up to 12 in (30 cm) by 2100.

‘The Amundsen Sea region in West Antarctica and Wilkes Land in East Antarctica are the two regions most sensitive to warming ocean temperatures and changing currents, and will continue to lose large amounts of ice,’ explains Hélène Seroussi, an ice scientist at NASA’s Jet Propulsion Laboratory in Southern California.

‘With these new results, we can focus our efforts in the correct direction and know what needs to be worked on to continue improving the projections.’

The new results will help inform the next iteration of the IPCC report scheduled for release in 2022.

Last year’s special report also found that by 2050, many coastal regions will experience once-a-century weather catastrophes every year, affecting millions.

It also said that sharp emissions cuts are needed to curb the changes as the world has already experienced 1°C of warming.

This has made the oceans warmer and more acidic and affected fish stocks, while melting glaciers and ice sheets.

KEY FINDINGS OF THE 2019 IPCC OCEAN REPORT

– Sea levels are rising at unprecedented rates, accelerating in recent decades as ice has been melting increasingly fast from Greenland and Antarctica.

They are set to rise at an increasing rate and will continue to do so beyond the year 2100 whatever level of emissions cuts are achieved.

Sea levels are set to rise by 30-60cm by 2100 with strong action to cut emissions and by around 60-110cm with high levels of pollution. Several metres of sea-level rise is predicted for 2300 in a high-emissions world.

– Since the mid-20th century, shrinking ice in the Arctic and the world’s high mountains have affected food and water security and quality, health, cultures of indigenous people, tourism and recreation such as skiing.

– Coastal communities are facing multiple threats linked to climate change , including more intense tropical cyclones, extreme sea levels and flooding, marine heatwaves, sea ice loss and melting permafrost – areas of previously permanently frozen ground.

The risk of erosion and flooding will increase significantly under all scenarios for future emissions, with annual coastal flood damages projected to increase 100 to 1,000 times by 2100.

– This century the ocean is set to shift to ‘unprecedented’ conditions, with higher temperatures and more acidic waters as carbon dioxide dissolves into the seas, while extreme El Nino and La Nina events, which affect global temperatures and weather, will become more frequent.

– Marine heatwaves have very likely doubled in frequency since 1982 and are increasing in intensity.

– Wildfires are set to increase across the tundra and cold northern forests, as well as some mountain regions.

– Marine wildlife and fish stocks are set to decline, while marine heatwaves and more acidic oceans will harm corals.

– Nearly half of the world’s coastal wetlands, which protect from erosion and flooding and are important carbon stores, have been lost over the last 100 years, as a result of human activity, sea level rises, warming and extreme events.

– Fragile habitats such as seagrass meadows and kelp forests are at high risk if global warming exceeds 2C above pre-industrial temperatures, while warm water corals are already at high risk and face ‘a very high risk’ even if global warming is limited to 1.5C.

– Some island nations are likely to become uninhabitable due to climate change.

– The resources provided by oceans and frozen areas can be supported by protecting and restoring them and reducing pollution and other pressures.

– Urgent and ambitious emissions reductions alongside coordinated, sustained and increasingly ambitious action to help people adapt to the changes that are taking place.

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