Devastating and scary news from the Arctic as Greenland has reached the tipping point. The melting of our northern freezer which allows our civilization to flourish has reached the point of no return, even if we cut our emissions to zero.
The tipping point is where snowfall “that replenishes the ice sheet each year cannot keep up with the ice that is flowing into the ocean from glaciers” according to a new study published yesterday in the journal Nature Communications Earth and Environment.
The loss of ice in Greenland ice can trigger other tipping points. “Ocean and atmospheric circulation and feedback between these interconnected climate shifts could accelerate the warming process, they warn, triggering a cascade of tipping points or even to a global tipping point – and a less habitable, “hothouse” Earth.”
The tipping point is not a simple melting of Greenland, that would take thousands of years as some swaths are miles deep in the ice. The point of no return is that the glacier's dynamics have changed due to surface melt percolating to the bedrock and, erosion of the glaciers by warming seawater. They are no longer stable.
King and other researchers analyzed monthly satellite data from more than 200 large glaciers draining into the ocean around Greenland. Their observations show how much ice breaks off into icebergs or melts from the glaciers into the ocean. They also show the amount of snowfall each year—the way these glaciers get replenished.
The researchers found that, throughout the 1980s and 90s, snow gained through accumulation and ice melted or calved from glaciers were mostly in balance, keeping the ice sheet intact. Through those decades, the researchers found, the ice sheets generally lost about 450 gigatons (about 450 billion tons) of ice each year from flowing outlet glaciers, which was replaced with snowfall.
"We are measuring the pulse of the ice sheet—how much ice glaciers drain at the edges of the ice sheet—which increases in the summer. And what we see is that it was relatively steady until a big increase in ice discharging to the ocean during a short five- to six-year period," King said.
The researchers' analysis found that the baseline of that pulse—the amount of ice being lost each year—started increasing steadily around 2000, so that the glaciers were losing about 500 gigatons each year. Snowfall did not increase at the same time, and over the last decade, the rate of ice loss from glaciers has stayed about the same—meaning the ice sheet has been losing ice more rapidly than it's being replenished.
"We are measuring the pulse of the ice sheet—how much ice glaciers drain at the edges of the ice sheet—which increases in the summer. And what we see is that it was relatively steady until a big increase in ice discharging to the ocean during a short five- to six-year period," King said.
The researchers' analysis found that the baseline of that pulse—the amount of ice being lost each year—started increasing steadily around 2000, so that the glaciers were losing about 500 gigatons each year. Snowfall did not increase at the same time, and over the last decade, the rate of ice loss from glaciers has stayed about the same—meaning the ice sheet has been losing ice more rapidly than it's being replenished.
There are nine active tipping points currently in the process: the Amazon rainforest drought, Arctic Sea Ice reduction, Atlantic Circulation slowing down since the 1950s, the massive Taiga forests susceptible to pests and fire, Coral Reefs experiencing large scale die-offs, Greenlands accelerating ice loss, the thaw of permafrost, and, East and West Antarctica ice loss.
The World Economic Forum writes:
How might such a climatic collapse happen? The authors point to the loss of Arctic sea-ice and the melting of Greenland’s ice sheet driving fresh water into the North Atlantic. They say this could have contributed to a 15% slowdown since the mid-20th century of the Atlantic Meridional Overturning Circulation (AMOC), a system of ocean currents that moves warm water northwards.
“Rapid melting of the Greenland ice sheet and further slowdown of the AMOC could destabilize the West African monsoon, triggering drought in Africa’s Sahel region,” they write.
“A slowdown in the AMOC could also dry the Amazon, disrupt the East Asian monsoon and cause heat to build up in the Southern Ocean, which could accelerate Antarctic ice loss.”
In their opinion, the West Antarctic ice sheet might already have passed a tipping point.
The “grounding line” at which ice, ocean and bedrock meet in a glacial system called the Amundsen Sea Embayment is retreating irreversibly.
Its collapse could destabilize the rest of the West Antarctic ice sheet like “toppling dominoes,” according to one computer model study, and lead to about 3 metres of sea-level rise “on a timescale of centuries to millennia.”
“If damaging tipping cascades can occur and a global tipping point cannot be ruled out, then this is an existential threat to civilization. No amount of economic cost–benefit analysis is going to help us. We need to change our approach to the climate problem.”
Two decades ago, scientists thought it would take a rise in global average surface temperature of 5°C above pre-industrial levels to reach tipping points in the climate system. Recent Intergovernmental Panel on Climate Change (IPCC) reports suggest this could occur between 1°C and 2°C.
The world has already warmed by more than 1°C. Even if countries implement their current pledges to reduce greenhouse-gas emissions, we are likely to see at least 3°C, despite the Paris agreement to keep warming well below 2°C.
Speaking ahead of the UN’s Climate Change Conference COP25 in Madrid, UN Secretary-General Antonio Guterres said efforts to reach global targets have been “utterly inadequate” and climate change could pass the point of no return.
Rest in Peace warrior.