A story on 16 Dec 2016 from the NASA Earth Observatory site said the Antarctic and Arctic sea ice amounts for November 2016 were both at record lows for that month. The Arctic is in the process of refreezing the surface sea ice as it goes into the winter months. The Antarctic is in the process of melting the sea ice as it goes into the summer months. A chart from the story shows the total amount of sea ice north and south from 1 Jan 1979 to 14 Dec 2016. There has been gradual decline in the total. For 2016, the total is significantly less for the last months of the year. An animated version of this chart is in the linked article.
Sea ice forms from water already in the oceans. Changes to the total does not alter sea level. Melting of land based ice drains into the oceans and does raise sea level. The decrease in total sea ice is due to shifting winds and warmer temperatures of the water. The underlying reasons and prognosis for future effects is an area of intense scientific study.
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The Arctic and Antarctic regions have reached their respective 2016 maximum and minimum polar ice extents. See the blue graph lines. The Arctic winter ice maximum extent was the smallest on record. The Antarctic summer ice minimum was slightly less than the recent 30 year average.
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There was much anticipation about the recent encyclical from Pope Francis on climate change. You can see and read the document at this link. No doubt you have seen and heard the news about it with some analysis of what is contained in it. I offer my impressions of the broad picture described in the 184 page document.
I’ve written a lot about climate change. It is one of the most important challenges faced by mankind. It will force us to deal with issues we already know about and some that we have yet to encounter. It will not go away if we ignore it.
Whether the encyclical is accepted by the world of Catholic leaders and followers will only be known by our actions in the future. There was a flurry of attention for a few days. Like many stories today, the attention has faded. I hope its messages are not forgotten.
Each chapter of the encyclical addresses aspects of the climate change problem I feel are very important. The document does not lay out a prescription for what humanity should do. It does serve as a reminder of our responsibilities to the Earth and to those less fortunate who do not have the means to help themselves easily. We all need reminders and guidance in those areas.
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Remember the record snowfall this winter in Boston and surroundings? It seemed endless. The record total for Boston was 108.6 inches. This image is from early February.
Charles Krupa | Associated Press
This map from NOAA shows liquid precipitation over the region for the recent 180 days since late November 2014. There are widespread locations with 20 inches. One in yellow near Boston had over 25 inches.
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Operation IceBridge Mission Statement
NASA’s Operation IceBridge images Earth’s polar ice in unprecedented detail to better understand processes that connect the polar regions with the global climate system. IceBridge utilizes a highly specialized fleet of research aircraft and the most sophisticated suite of innovative science instruments ever assembled to characterize annual changes in thickness of sea ice, glaciers, and ice sheets.
Now in the seventh year, IceBridge is deep into the Arctic research campaign. Each year, the aircraft fly over the Arctic or the Antarctic to gather data on the ice and how it is responding to climate change. The data is related to that of other research efforts such as ice core drilling and satellite observations. One of the regions intensely studied is Greenland which is 85% covered by ice to up to an average depth of 2.3 km (1.6 miles). The great weight of the ice has pressed the central rock layers of Greenland down 300 m (1000 ft) below sea level. There is enough ice on Greenland to raise sea level by 7 m (23 ft) if it were to all melt. Knowing the structure and past history during previous climate eras will help understand the prospects for future behavior. To that end, IceBridge researchers released this 3-D visualization animation of the ice layers. It was produced by the NASA Goddard Scientific Visualization Studio. Run time is 3 min 37 sec.
The reports from studies of the extent of sea ice in the polar regions show opposite trends. The north Arctic region is losing areal coverage. The south Antarctic region is gaining areal coverage of sea ice. I discussed these two opposite trends in this recent post. The question many people have is whether this is a bad thing or not. Doesn’t the gain in the south cancel out the loss in the north so it comes out equal?
Claire Parkinson is in her fourth decade of studying polar sea ice. She often got that question from audiences after her presentations. She examined data from 1979 thru 2013 and charted the results below. It is clear the Arctic sea ice losses are profound in the first graph. Also clear is the trend of increases in the Antarctic sea ice in the second graph. That increase is not as large as the losses, however. The third graph shows the Combined data and the overall global decrease. More details of this story can be found at this link at NASA Earth Observatory.
Earth has been shedding sea ice at an average annual rate of 35,000 square kilometers (13,500 square miles) since 1979—the equivalent of losing an area of sea ice larger than the state of Maryland every year.
Earth Observatory | Joshua Stevens | Maria-Jose Viñas | Mike Carlowicz
References and Related Reading