The Environment

Some Topics

 

YINYANG

Polar Ice Caps

The north and south ice caps store water as ice and snow. Melting ice in these regions adds to ocean water , raising ocean levels. Coastal zones are threatened by rising ocean levels. National Geographic published a review of arctic ice melting: ” Every winter almost the entire surface of the Arctic Ocean freezes over. The ice typically reaches its maximum extent in March, then starts to melt, receding to its minimum in September. But the melt season is now three weeks longer than it was just four decades ago. Less ice survives the summer to thicken the following winter. The summer ice is also less concentrated, with more open water between floes. Because open water absorbs more solar heat, more ice melts, creating a positive feedback that amplifies the Baffin warming and melting. The Arctic Bay will continue to freeze in winter—but it could be ice free in summer by 2040. Maps of the Arctic in March and charts of the ice’s age show a 75 percent decline in the oldest, thickest ice—ice that has survived at least four summers and is into its fifth year or more. Most sea ice now freezes and melts in less than a year.”

In the USA the National Snow and Ice Data Center publishes current measurements online. In November 2016, they reported:” In October 2016, Arctic sea ice extent averaged 6.40 million square kilometers (2.5 million square miles), the lowest October in the satellite record. This is 400,000 square kilometers (154,400 square miles) lower than October 2007, the second lowest October extent, and 690,000 square kilometers (266,400 square miles) lower than October 2012, the third lowest. The average extent was 2.55 million square kilometers (980,000 square miles) below the October 1981 to 2010 long-term average.”[i]

Thompson reported on 2017 findings:” Temperatures in the Arctic are rising at twice the rate of the planet as a whole, and the accompanying ice loss means that walruses and polar bears are losing critical habitat, more of the fragile local ecosystem is being opened up to shipping, and waves from storms can more easily batter coastal settlements. The reduced amount of sea ice may also be causing heat to be released into the atmosphere that is altering wind patterns and weather over the U.S., Europe and Asia. In a few weeks, sea ice area will have dropped below the average annual low of the 1990s, which is noticeably below that of the ‘80s. As warming continues, sea ice will reach those milestones earlier and earlier in the year, until the Arctic potentially reaches the point where it is effectively ice free in the summer.[ii]

Climate Tipping Points

Climate tipping points occur when a natural system, such as the polar ice cap, undergoes sudden or overwhelming change that has a profound effect on surrounding ecosystems, often irreversible. In the Arctic, the tipping points identified in a report compiled by 11 organizations including the Arctic Council (Nov 2016): “ growth in vegetation on tundra, which replaces reflective snow and ice with darker vegetation, thus absorbing more heat; higher releases of methane, a potent greenhouse gas, from the tundra as it warms; shifts in snow distribution that warm the ocean, resulting in altered climate patterns as far away as Asia, where the monsoon could be effected; and the collapse of some key Arctic fisheries, with knock-on effects on ocean ecosystems around the globe.” [iii]

The Antarctic is the southern polar ice. NASA summarized the differences observed before 2014:” Antarctica and the Arctic are two different environments:the former is a continent surrounded by ocean, the latter is ocean enclosed by land. As a result, sea ice behaves differently in the two regions. While the Antarctic sea ice yearly wintertime maximum extent hit record highs from 2012 to 2014 before returning to average levels in 2015, both the Arctic wintertime maximum and its summer minimum extent have been in a sharp decline for the past decades.” [iv]

A newer and closer look at the Antarctica has been achieved by Operation IceBridge , NASA’s airborne survey of changes in polar ice. NASA reported:” Antarctica is heading into austral summer, a period of rapid sea ice melt in the Southern Ocean. But this year the sea ice loss has been particularly swift and the Antarctic sea ice extent is currently at the lowest level for this time of year ever recorded in the satellite record, which began in 1979. "We flew over the Bellingshausen Sea many times and saw that areas that are typically covered by sea ice were just open water this year. It is it is important that we measure both changes in sea ice extent and in sea ice thickness to assess the future trajectory of the ice pack and its impact on the climate.” [vi]

A large ice shelf , described as three zones, Larsen A,B,C has been collapsing for three decades. A report revealed that Larsen C crack" is breaking free. A 100 mile crack grew 17 miles in 2017. Mooney reported: ”It’s the latest sign of major ice loss in the fast warming Antarctic Peninsula, which has already seen the breakup of two other shelves in the same region, events that have been widely attributed to climate change. The crack in the ice shelf, Larsen C, has been growing at an accelerating rate. Since the beginning of December, it has grown about 11 miles in length, after extending 13 miles earlier in the year. In total, the rift has grown about 50 miles since 2011 and has widened to well over 1,000 feet. Now, only 12 miles of ice continue to connect the chunk with the rest of the ice shelf.”[vii]
In July 2017 the large chunk of ice floated free, becoming the largest iceberg recorded.

[i] National Snow and Ice Data Center .Accessed Online Dec. 2016 http://nsidc.org/arcticseaicenews/

[ii] Andrea Thompson .Here’s How Much Arctic Sea Ice Has Melted Since the ‘80s. Climate Central - Friday, July 21, 2017 Accessed Online: http://www.climatecentral.org/news/arctic-sea-ice-melt-since-the-80s-21637

[iii] Iiona Harvey . Arctic ice melt could trigger uncontrollable climate change. The Guardian - November 25, 2016

[iv] NASA. Antarctic Sea Ice Reaches New Record Maximum https://www.nasa.gov/content/goddard/antarctic-sea-ice-reaches-new-record-maximum. Oct 2014.

[vi] NASA Nears Finish Line of Annual Study of Changing Antarctic Icehttps://www.nasa.gov/feature/goddard/2016/nasa-nears-finish-line-of-annual-study-of-changing-antarctic-ice. Accessed Online Nov 2016.

[vii] Mooney,C . The crack in this Antarctic ice shelf just grew by 11 miles. A dramatic break could be imminent. Washington Post. Energy and Environment, Jan 6 2017.

 
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