"Just the little bit of extra heat from a tiny soot particle can start transforming feathery and highly reflective snow crystals into darker, rounded grains that absorb more heat." —Jason Box
Breaking: Miami, New York and other coastal cities take heed.
From Climate Central:
Global average sea level is expected to rise by one foot between 2000 and 2050 and by several more feet by the end of the century under a high-pollution scenario because of the effects of climate change, according to the projections in the new peer-reviewed study. It shows 21st century sea-level rise could be kept to less than two feet if greenhouse gas emissions are aggressively and immediately reduced, reflecting a larger gap in sea-level consequences between high and low emissions scenarios than previous research has indicated.
Just look at this chunk of bare ice that broke off Illusiatt Glacier. Yow!
Glaciologists have known for a very long time that mineral dust, soot from wildfire and black carbon darken the surface Greenland. These impurities are studied because they reduce the ice sheet's albedo, “or the extent to which it reflects light, which increases melting of the ice and affects projections of sea level rise”. Algae feed on these aerosol particles trapped on Greenland’s snow and ice. The algae then proliferate, hinting at yet another worrying feedback cycle. Once the algae blooms, then the Dark Zone expands. The dark zone is the mix of soot, dust and algae and it can be seen from orbit. It is also known as Dark Snow.
Satellite images have confirmed that the Greenland ice sheet (which holds 23 feet of sea level rise) “has a continuous ablation zone that’s 400 kilometers wide (250 miles) and 100 kilometers (62 miles) up from the margin of its western flank. The dirty-looking area is bounded and perhaps pockmarked by plenty of those beautiful, ominous meltwater lakes – and, as the paper notes, it’s been getting bigger”.
Inside Climate News has the must-read story on the newly discovered feedback loop published in the scientific journal Nature. It is well worth the read. Some excerpts:
In western Greenland, the dark zone is about the size of West Virginia. It grew by 12 percent between 2000 and 2012, and new research suggests it's likely to continue to expand, according to climate researcher Jason Box, who travels wide swaths of the ice sheet each summer to collect samples for the Geological Survey of Denmark and the Dark Snow project.
The new research, published in the journal Nature Communications, describes a geological feedback loop on the ice that's expanding the dark zone: Warming melts the western edge of the ice sheet, releasing mineral dust from rock crushed by the ice sheet thousands of years ago. That dust blows to the surface of the ice, nurturing the microbes and algae living there. Those organisms produce colored pigments as sunscreen, which contribute to the darkening of the surface, reducing reflectivity and increasing melting.
snip
Last summer, unusual peat fires in Greenland's drying permafrost released about 23 tons of carbon near the ice sheet. By the scale of North American or Siberian wildfires, the Greenland fires weren't all that big, but their proximity increased the amount of black carbon particles falling on the ice sheet, Norwegian researcher Andreas Stohl said during the EGU meeting. He noted that Greenland's permafrost is thawing faster than expected now.
The research shows that wildfires in Siberia and Northern Canada are contributing to the darkening of the ice sheet.
"These are the dirtiest clouds on Earth. They are chimneys for pollution," Morton said. The tiny particles from the fires lingered in the Northern Hemisphere's atmosphere for a month, each molecule of black carbon trapping 3,200 times more heat than CO2 over a 20-year span. Caught up in seasonal northwest winds, some of that soot ended forming nuclei for snowflakes that fell on Greenland.