In the Arctic, the Old Ice Is Disappearing

In the Arctic, the Old Ice Is Disappearing

SOURCE: New York Times DATE: May 14, 2018 SNIP: In the Arctic Ocean, some ice stays frozen year-round, lasting for many years before melting. But this winter, the region hit a record low for ice older than five years. This, along with a near-record low for sea ice over all, supports predictions that by midcentury there will be no more ice in the Arctic Ocean in summer. As darker, heat-absorbing water replaces reflective ice, it hastens warming in the region. Older ice is generally thicker than newer ice and thus more resilient to heat. But as the old ice disappears, the newer ice left behind is more vulnerable to rising temperatures. “First-year ice grows through winter and then to up to a maximum, which is usually around in March,” said Mark A. Tschudi, a research associate at the Colorado Center for Astrodynamics Research at the University of Colorado, Boulder. “As summer onsets, the ice starts to melt back.” Some of the new ice melts each summer, but some of it lingers to grow thicker over the following winter, forming second-year ice. The next summer, some of that second-year ice survives, then grows even thicker and more resilient the next winter, creating what is known as multiyear ice. Some ice used to last more than a decade. Today, Arctic sea ice is mostly first-year ice. While the oldest ice has always melted when currents pushed it south into warmer waters, now more of the multiyear ice is melting within the Arctic Ocean, leaving more open water in its wake. “I’ve been on record saying that it may be 2030 that...
Alien Waters: Neighboring Seas Are Flowing into a Warming Arctic Ocean

Alien Waters: Neighboring Seas Are Flowing into a Warming Arctic Ocean

SOURCE: Yale e360 DATE: May 10, 2018 SNIP: As the Arctic heats up faster than any other region on the planet, once-distinct boundaries between the frigid polar ocean and its warmer, neighboring oceans are beginning to blur, opening the gates to southern waters bearing foreign species, from phytoplankton to whales. The “Atlantification” and “Pacification” of the Arctic Ocean are now rapidly advancing. A new paper by University of Washington oceanographer Rebecca Woodgate, for example, finds that the volume of Pacific Ocean water flowing north into the Arctic Ocean through the Bering Strait surged up to 70 percent over the past decade and now equals 50 times the annual flow of the Mississippi River. And over on the Atlantic flank of the Arctic, another recent report concludes that the Arctic Ocean’s cold layering system that blocks Atlantic inflows is breaking down, allowing a deluge of warmer, denser water to flood into the Arctic Basin. “You have all this warm Pacific water coming into the Arctic and what is that going to mean?” says Robert Pickart, a physical oceanographer with the Woods Hole Oceanographic Institution in Massachusetts who studies Pacific Arctic circulation. “Not only is there more water going through, but there’s an increase in the amount of heat going through.” Adding more heat, he says, is “going to change the composition of the water and its likelihood to melt sea ice.” In addition, waters from the Atlantic that have long entered the Arctic Ocean and circled down deep are being driven higher onto shallow sea shelves north of Alaska by increasingly intense storms. (The Arctic’s extensive sea ice cover used...
Shock and Thaw—Alaskan Sea Ice Just Took a Steep, Unprecedented Dive

Shock and Thaw—Alaskan Sea Ice Just Took a Steep, Unprecedented Dive

SOURCE: Scientific American DATE: May 2, 2018 SNIP: Winter sea ice cover in the Bering Sea did not just hit a record low in 2018; it was half that of the previous lowest winter on record (2001), says John Walsh, chief scientist of the International Arctic Research Center at the University of Alaska Fairbanks. “There’s never ever been anything remotely like this for sea ice” in the Bering Sea going back more than 160 years, says Rick Thoman, an Alaska-based climatologist with the National Oceanic and Atmospheric Administration. [T]his year sea-ice coverage as of late April was more like what would be expected for mid-June, well into the melt season. These conditions are the continuation of a winter-long scarcity of sea ice in the Bering Sea—a decline so stark it has stunned researchers who have spent years watching Arctic sea ice dwindle due to climate change. The occurrence of these unusual conditions off Alaska this past winter can largely be chalked up to the random weather variations in a chaotic climate system, Bond, Walsh and Thoman all say—but they add that global warming likely amped up the severity of the situation. Because of the role the weather plays, though, “every year is not going to be like this,” Thoman says. “Next year will almost certainly not be this low.” But as temperatures continue to rise, he says, “odds are very strong that we will not go another 160 years before we see something like this” happen...
We’re witnessing the fastest decline in Arctic sea ice in at least 1,500 years

We’re witnessing the fastest decline in Arctic sea ice in at least 1,500 years

SOURCE: Vox and Inside Climate News DATE: February 17, 2018 SNIP: Vox: The Arctic Ocean once froze reliably every year. Those days are over. Arctic sea ice extent has been measured by satellites since the 1970s. And scientists can sample ice cores, permafrost records, and tree rings to make some assumptions about the sea ice extent going back 1,500 years. And when you put that all on a chart, well, it looks a little scary. “The Arctic is going through the most unprecedented transition in human history,” Jeremy Mathis, director of NOAA’s Arctic research program, said at a press conference. “This year’s observations confirm that the Arctic shows no signs of returning to the reliably frozen state it was in just a decade ago.” The report, which you can read in full here, compiles trends that scientists have been seeing for years. The Arctic is warming at twice the rate of the rest of the world. And 2017 saw a new record low for the maximum sea ice extent (i.e., how much of the Arctic ocean freezes in the coldest depths of winter). That huge drop-off at the end? That’s “the largest magnitude decline in sea ice, and the greatest sustained rate in sea ice decline in that 1,500-year record,” said Emily Osborne, the NOAA scientist who compiled the data for the chart. Inside Climate News: In just eight days in mid-February, nearly a third of the sea ice covering the Bering Sea off Alaska’s west coast disappeared. That kind of ice loss and the changing climate as the planet warms is affecting the lives of the people who...
Sea ice tracking low in both hemispheres

Sea ice tracking low in both hemispheres

SOURCE: National Snow and Ice Data Center (NSIDC) DATE: February 6, 2018 SNIP: January of 2018 began and ended with satellite-era record lows in Arctic sea ice extent, resulting in a new record low for the month. Combined with low ice extent in the Antarctic, global sea ice extent is also at a record low. The linear rate of decline for January is 47,700 square kilometers (18,400 square miles) per year, or 3.3 percent per...