Rapid sea-level rise likely as Greenland ice-melt accelerates towards the worst-case scenario.

And what seems clear now is that Greenland is no longer changing in geological time. It is changing in human time. Jon Gertner, Yale Environment 360
In Madrid at the COP 25 (Conference of the Parties consists of two hundred negotiators that signed onto the 1992 United Nations Framework Convention on Climate Change), climate negotiators are attempting to limit the sea-level rise to six and a half feet of sea-level rise. Research on past climates, however, suggests that 65 feet of sea-level rise are inevitable. Sixty-five feet is roughly the height of a six-story building. 

James White of the University of Colorado has expertise in ancient climates, and he states unequivocally that “the coast is toast.” 

White has warned that “large climate changes tend to occur in the natural system as abrupt and rapid shifts in mode probably driven by internal adjustments in the Earth climate system, rather than slow and gradual adjustments to changing external conditions, such as the amount of energy received from the sun.” In other words, the planets’ coast will see flooding and storm surge that is dramatic, disruptive, and abrupt.

For years the mountain glaciers were the primary source of sea-level rise. Now Greenland, one of three critical air conditioners for the earth (Greenland, Antarctica and, the Himalayas) that keep our climate stable providing the conditions needed for life, as well as human civilization, to flourish. 

Eighty percent of Greenland is ice. At the center of the island, the depth is two miles.

Jon Gertner of Yale Climate 360 wrote in July of 2019:

Many scientists who have spent their careers on the ice sheet have witnessed these changes firsthand. Konrad Steffen, who has built up a record of meteorological readings around Greenland over the course of the past 30 years, has calculated that between 1990 and 2018 average temperatures on the ice sheet have increased by about 2.8 degrees Celsius, or 5 degrees Fahrenheit. While the highest points on the ice sheet are still mostly resistant to melting, over the same 30-year time period the total area of the ice sheet that has become vulnerable to surface melting has increased by around 65 percent. And what seems clear now is that Greenland is no longer changing in geological time. It is changing in human time.

Greenland’s ice is not only beset by warming air. It is beset by warming water, too.
In recent years, about half of the island’s ice has been lost from surface melt. But another half has been drained by massive glaciers — such as Jakobshavn on the west coast and Helheim on the east — that branch off from the ice sheet and end at the water’s edge. These so-called “marine terminating” glaciers seem especially sensitive to warming ocean temperatures that can accelerate iceberg losses and increase melting where the glaciers’ calving fronts meet the water. Jakobshavn, for instance — for decades one of the fastest and most active glaciers in the world — accounts for about 4 percent of sea level rises during the 20th century.

Ice is being lost in Greenland seven times faster than it was in the 1990s, according to a new study published in the Journal Nature, exposing four hundred million people to risk from rising waters.

Fiona Harvey of The Guardian writes on the study findings.

Oceans have absorbed most of the excess heat arising from our disruption of the climate to date, and much of the carbon dioxide, but they are reaching the limits of their capacity to do so. Sea level rises are driven not only by melting ice but by the thermal expansion of the seas as they warm.
The scale and speed of the ice loss surprised the team of 96 polar scientists behind the findings, published on Tuesday in the journal Nature. The Ice Sheet Mass Balance Inter-comparison Exercise comprised 26 separate surveys of Greenland from 1992 to 2018, with data from 11 different satellites and comparisons of volume, flow and gravity compiled by experts from the UK, Nasa in the US, and the European Space Agency.
Note that the study time period is 1992-2018. It does not include the melt season of 2019 which has surpassed the record melt season of 2011.

The Greenland Ice Sheet is rapidly melting, having lost 3.8 trillion tons of ice between 1992 and 2018, a new study from NASA and the European Space Agency (ESA) finds. The study combined 26 independent satellite datasets to track global warming’s effect on Greenland, one of the largest ice sheets on Earth, and the ice sheet melt’s impact on rising sea levels. The findings, which forecast an approximate 3 to 5 inches (70 to 130 millimeters) of global sea level rise by 2100, are in alignment with previous worst-case projections if the average rate of Greenland’s ice loss continues.

Changes to the Greenland and Antarctic ice sheets are of considerable societal importance, as they directly impact global sea levels, which are a result of climate change. As glaciers and ice sheets melt, they add more water to the ocean. Increasing rates of global warming have accelerated Greenland’s ice mass loss from 25 billion tons per year in the 1990s to a current average of 234 billion tons per year. This means that Greenland’s ice is melting on average seven times faster today than it was at the beginning of the study period. The Greenland Ice Sheet holds enough water to raise the sea level by 24 feet (7.4 meters).

“As a rule of thumb, for every centimeter rise in global sea level, another 6 million people are exposed to coastal flooding around the planet,” said Andrew Shepherd, lead author and scientist from the University of Leeds in the United Kingdom. “On current trends, Greenland ice melting will cause 100 million people to be flooded each year by the end of the century, so 400 million in total due to sea level rise.”

In addition to storm surges and high tides that will increase flooding in many regions, sea level rise exacerbates events like hurricanes. Greenland’s shrinking ice sheet also speeds up global warming. The vast expanse of snow and ice helps cool down Earth by reflecting the Sun’s rays back into space. As the ice melts and retreats, the region absorbs more solar radiation, which warms the planet.

The new study will contribute to the evaluation and evolution of sea level rise models used by the Intergovernmental Panel on Climate Change in evaluating risks to current and future populations. The results of the study currently appear consistent with the panel’s worst-case projections for sea level rise in the next 80 years.

“The full set of consequences of future melt from the Greenland Ice Sheet remain uncertain, but even a small increase in sea level can have devastating effects on ports and coastal zones, cause destructive erosion, wetland flooding, and aquifer and agricultural soil contamination with salt,” said Ivins.

Fascinating drone footage of a meltwater lake draining rapidly and creating what is likely the tallest waterfall on earth.