Active NASA Photo of Arctic Sea Ice

Arctic Ocean Could Be Ice-Free Before Midcentury

From an Article by Tim Radford, Climate Network News, November 5, 2016

The average American is responsible for the melting of almost 50 square meters of ice per year.

LONDON — Two scientists have worked out what it would take to melt all the ice in the Arctic Ocean.

If their sums are right, then by the time human beings have burned enough fossil fuels to add 1,000 billion tons of carbon dioxide to the atmosphere, the Arctic Ocean will be free of ice in September—the annual minimum—and the world’s shipping will have a new, safe, fast route across the Arctic Circle.

Quite when this moment will happen depends entirely on the rate that humans add greenhouse gases to the atmosphere. But the two researchers calculate that for every metric ton of carbon dioxide emitted, the Arctic will lose 3.3 square metres of sea ice.

Melt rate: That means the average American, with the world’s highest use of fossil fuels per head, is now melting almost 50 square metres a year.

Right now, humanity in total is releasing 35 billion tons of CO2 into the atmosphere each year, so the 1,000-billion-ton mark will be achieved before mid-century, and the north polar ocean ice will drop for the first time below 1 million square kilometres, leaving the Arctic almost entirely open sea.

Climate scientists predicted years ago that—at present rates of melting—the Arctic could be ice-free in September by mid-century. What Dirk Notz of the Max Planck Institute for Meteorology in Hamburg in Germany and Julienne Stroeve of the National Snow and Ice Data Center (NSIDC) in Boulder, Colorado, in the US, report in the US journal Science is that they have established a direct correlation between emissions and ice loss.

They looked at the average area of sea ice every September for the last 30 years—since satellite instruments began to deliver accurate data—and matched that against the cumulative carbon emissions for the last three decades.

The two call the relationship “robust”: there might be all sorts of reasons why over a long historical period Arctic sea ice would vary from year to year, but as greenhouse gas levels rise, CO2 becomes the dominant force that makes the ice retreat.

This year the ice began melting with great rapidity, and according to the NSIDC the area of frozen sea dwindled to an average of 4.72 million square kilometres, the fifth lowest in the satellite record. It is now freezing again, very fast.

Arctic waters: But the US Office of Naval Research reports that it has already begun to explore the open waters. Researchers this summer began measuring the strength and intensity of waves and swells moving through the increasingly weakened sea ice. They also used acoustic sensors to test the conditions for sonar operations and antisubmarine warfare.

That is because the retreat of the ice opens up new commercial shipping lanes, makes possible greater oil and gas exploration and new fisheries—and new challenges for the US Navy’s surface fleet. The goal is to understand the changing conditions.

“Abundant sea ice reduces waves and swells and keeps the Arctic Ocean very quiet,” says Robert Headrick, who manages the research programme.

“With increased sea ice melt, however, come more waves and wind, which creates more noise and makes it harder to track undersea vessels.”

Tim Radford, a founding editor of Climate News Network, worked for The Guardian for 32 years, for most of that time as science editor. He has been covering climate change since 1988.

>  >  >  >  >  >  >  >  >  >  >

ARCTIC SEA ICE — Why We Are Losing Arctic Sea Ice

H. Jesse Smith, Science, November 11,  2016: Vol. 354, Issue 6313, pp. 716-717

Summary: Arctic sea ice is disappearing rapidly, leading to predictions of an ice-free summer in the near future. Simulations of the timing of summer sea-ice loss differ substantially, making it difficult to evaluate the pace of the loss. Notz and Stroeve observed a linear relationship between the monthly-mean September sea-ice area and cumulative CO₂ emissions. This allowed them to predict Arctic summer sea ice directly from the observational record. Interestingly, most models underestimate this

Abstract: Arctic sea ice is retreating rapidly, raising prospects of a future ice-free Arctic Ocean during summer. Because climate-model simulations of the sea-ice loss differ substantially, we used a robust linear relationship between monthly-mean September sea-ice area and cumulative carbon dioxide (CO₂) emissions to infer the future evolution of Arctic summer sea ice directly from the observational record.

The observed linear relationship implies a sustained loss of 3 ± 0.3 square meters of September sea-ice area per metric ton of CO₂ emission. On the basis of this sensitivity, Arctic sea ice will be lost throughout September for an additional 1000 gigatons of CO₂ emissions.

Most models show a lower sensitivity, which is possibly linked to an underestimation of the modeled increase in incoming longwave radiation and of the modeled transient climate response.

Reference:

Observed Arctic Sea-ice Loss Directly Follows Anthropogenic CO₂ Emissions

Dirk Notz and Julienne Stroeve, Science, Nov 11, 2016 — Vol. 354, Issue 6313, pp. 747-750

>  >  >  >  >  >  >  >  >  >  >

Greenland Is Melting – The New Yorker Magazine

Greenland Is Melting: A Song of Ice

From an Article by Elizabeth Kolbert, The New Yorker, October 24, 2016

The shrinking of the country’s ice sheet is triggering feedback loops that accelerate the global crisis. The floodgates may already be open.

When water accumulates on the surface of an ice sheet, more sunlight gets absorbed, which results in more melt, in a cycle that builds on itself. This year’s melt season began so early that many scientists couldn’t believe the data they were seeing.

See this full article here.

High Temperatures in Arctic Region

Watch 25 Years of Arctic Sea Ice Melt in One Minute

From a Posting by Stefanie Spear, EcoWatch.com, December 27, 2015

Recent social media posts by The Climate Reality Project are featuring the National Oceanic and Atmospheric Administration (NOAA) one-minute video animation that tracks the relative amount of ice of different ages from 1987 through early November 2014.

According to NOAA, decades ago, the majority of the Arctic’s winter ice pack was made up of thick, perennial ice. Today, very old ice is extremely rare.

Check out the video, produced by the Climate.gov team and based on data provided by Mark Tschudi, here:

NOAA 25 Year Animated Video

Video shows 25 years of Arctic sea ice disappearing in one minute (via @NOAA). It’s time to #ActOnClimate.