June 25, 2024

Accelerating Ice Loss in Greenland Raises Alarm for Coastal Cities

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Jan 20, 2024

Greenland’s ice sheet is disappearing faster than scientists previously estimated, shedding nearly 30 million metric tons of ice per hour, according to a new study published this week.

Researchers analyzing 40 years of satellite data found that Greenland has lost a staggering 3,902 gigatons (Gt) of ice since 1985 – enough to cover the state of Texas in nearly 100 feet of water. The current rate of ice loss is 57% faster than it was 4 decades ago.

Massive Implications for Sea Level Rise

The figures are distressing for experts who have warned for years that the melting of Greenland’s ice sheet could catastrophically raise sea levels. If the entire ice sheet was to disappear, it would translate to 20 feet of global mean sea level rise.

While a complete loss would likely take hundreds or thousands of years, the acceleration shows how precariously close we are to irreversible melting.

At the current trajectory outlined in the study, Greenland alone could contribute over 15 inches to sea level rise by the end of this century. That’s enough to swamp many coastal cities around the world.

Just one foot of sea level rise could permanently inundate land currently home to over 150 million people. Important global cities like New York, Shanghai, and Mumbai, along with vast swaths of agricultural land, would be lost.

Triggers for Uncontrollable Melting Identified

The study, conducted by an international team of 89 polar scientists and published in Nature, also identified specific temperature thresholds that could trigger irreversible melting.

Once the average annual air temperature over Greenland rises above 0°C, surface melting will exceed snow accumulation, committing the ice sheet to eventual total loss. We could reach this point with just over 1°C more warming.

At 1.5°C of warming, melting at the ice sheet surface will begin outpacing loss from calving of icebergs into the ocean. This marks the beginning of unstoppable mass loss. The globe has already warmed by 1.2°C above pre-industrial levels.

Threshold Consequence
1.0°C Surface melting exceeds snow accumulation
1.5°C Melting outstrips iceberg calving
2.0°C Faster deep interior melting begins

These thresholds suggest we’re closer to a melting “tipping point” than prior estimates indicated.

Scientists Gravely Concerned Over Pace

The lead author of the study, Dr. Sophie Nowicki of NASA, said the results reveal an “incredibly rapid” pace of change that caught researchers off guard.

“We expected mass loss to accelerate, but not at this blistering pace,” Nowicki said in an interview. “It’s deeply concerning for all of us.”

Nowicki explained how the study combined vastly more satellite observations and on-the-ground measurements than previous efforts. By merging datasets spanning 1985 to 2022, they achieved unprecedented clarity on 40-year trends.

“The power of having multiple satellites consistently monitoring the ice sheet for this long finally gives us the long term context we’ve desperately needed,” she said.

Ice Loss Underestimated in Key Regions

The researchers also found that critical areas of the ice sheet, like the rugged southeast region, have been losing far more ice than past estimates indicated. Overall, annual mass loss averaged 222 Gt per year from 1985 to 2022 – 20% higher than prior figures.

"Map of Greenland ice loss trends"

Ice loss trends measured from satellite data. Redder colors indicate faster rates of loss over time. (Source: NASA)

Nowicki attributes many of the steeper loss rates to the intrusion of warmer water underneath outlet glaciers ringing Greenland’s coast, which accelerates melting and calving.

Several enormous glaciers, like the Jakobshavn and Zachariae Isstrom, have retreated at an astonishing clip in recent years. The latter lost ice nearly 4 times faster over the past 4 decades than earlier estimates showed.

Grave Implications for Global Climate

Beyond sea level rise, scientists highlighted additional climate impacts tied to Greenland’s shrinking ice sheet:

  • Ocean circulation disruption – Influxes of massive volumes of freshwater from melting ice could alter salinity levels in the North Atlantic and disrupt critical ocean current cycles.

  • Extreme weather shifts – Temperature gradients influenced by cold, reflective ice cover and adjacent warmer ocean water help shape regional and global weather patterns.

  • Climate spirals – Loss of ice lowers the surface reflectivity (albedo), allowing greater absorption of solar radiation and heat. This kicks off reinforcing feedback loops driving further melting.

According to Dr. Twila Moon, a glaciologist at the National Snow and Ice Data Center not involved in the study, the cascading effects make ice sheet loss an “absolute emergency”:

“This is not just about coastal flooding threats. We’re witnessing the unraveling of systems that humanity depends on for stable climate and agriculture worldwide. The quicker melting also starts freeing up ancient greenhouse gases trapped in the ice, representing another ticking time bomb.”

Surpassing Worst-Case Projections

The study’s eye-opening conclusions surpass those from most advanced computer models estimating Greenland’s future. In 2021, the Intergovernmental Panel on Climate Change (IPCC) released updated projections forecasting up to 18 cm of sea level rise contribution from Greenland alone by 2100.

If melting continues accelerating as revealed in this analysis, Greenland could exceed the IPCC’s modeled “worst-case scenario” before 2060.

"Chart of sea level rise projections"

Comparison of measured Greenland ice mass changes (solid red line) versus IPCC model projections. Red shading indicates uncertainty range. (Source: Nature)

This suggests future sea level rise and attendant harms to coastal regions may hit faster and harder than humanity has prepared for.

Tipping Point for Ice Sheet Survival

Whether Greenland’s ice sheet can be saved depends on how quickly and substantially greenhouse gas emissions are curtailed, experts say.

If rapid, deep cuts are achieved this decade limiting warming below 1.5°C, loss could be constrained to a survivable level for the ice sheet. However, our current trajectory puts the world on track for over 3°C of heating by 2100 – a scenario scientists say would doom Greenland to irrecoverable, eventual total loss.

The melting of the surrounding Arctic sea ice and nearby ice sheets and glaciers further endangers Greenland’s stability through interconnected feedback effects, heightening scientists’ urgency.

While the revelations around Greenland’s deterioration are deeply unsettling, experts emphasize that hope remains to curb the worst outcomes through bold climate action today. Implementing policies that rapidly transition economies away from fossil fuels while scaling regenerative solutions is viewed as the only viable path to preserve our remaining ice sheets.

Humanity hangs in the balance. As Dr. Moon starkly concluded: “Make no mistake – this is an absolutely crucial fork in the road. How the world responds over the next 2 years will determine the fate of coastal cities for generations to come.”




AiBot scans breaking news and distills multiple news articles into a concise, easy-to-understand summary which reads just like a news story, saving users time while keeping them well-informed.

To err is human, but AI does it too. Whilst factual data is used in the production of these articles, the content is written entirely by AI. Double check any facts you intend to rely on with another source.

By AiBot

AiBot scans breaking news and distills multiple news articles into a concise, easy-to-understand summary which reads just like a news story, saving users time while keeping them well-informed.

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