Thereís a website I frequent from the National Snow and Ice Data Center which has some great current and historical information about the Arctic, Antarctic and Greenland ice coverage. This organizationís research and scientific data management activities are supported by NASA, the National Science Foundation (NSF), the National Oceanic and Atmospheric Administration (NOAA). They receive other funding via contracts, grants and other agencies.
The center itself is part of the Cooperative Institute for Research in Environmental Sciences (CIRES) at the University of Colorado at Boulder, I find the information very well presented and easy to understand. The statistics and images I used for this blog entry come from that website.
We hear a lot of chatter about global sea ice, mostly in the arctic region because thatís where the ice has declined over the past several decades. During the past 12 months itís been interesting to see how the decline in the ice has slowed and there has been an increase in multi-year ice as well. One year doesnít buck a trend and it may be but a blip in the overall decline. Nevertheless itís important to note.
Back on the first day of spring, the ice in the arctic reached its maximum for the year. At 14.91 million square kilometers (5.76 million square miles), this was the fifth lowest maximum in the satellite record which dates back to 1979. While certainly significant, 35 years of data is a very small subset of geological time.
At the other end of the planet during our winter, the Antarctic ice sheet is undergoing its yearly loss of ice. This year, the sea ice reached its annual minimum on February 23, and was the fourth highest Antarctic minimum in the satellite record. You can see on the image below the trend is quite the opposite of what's going on at the top of the planet.
One of the more interesting pieces of ice data to me is this idea of multi-year ice. In winter, many of our own lakes and ponds are iced over, but the ice melts each spring. In the arctic parts of the arctic have always melted, but much of the ice has remained for multiple years. The multi-year ice is stronger than the annual ice. Multi-year ice is also thicker and plays a role in reflecting the sunís solar rays back to space.
There was a dramatic jump in multi-year ice this winter from 30% in 2013 to 43%. Back in 2007 the multi-year ice was at 46%, that summer there was a tremendous amount of melting and you can see on the chart below the spike downward that season.
So what will happen this summer? It will be very interesting to see if the arctic ice continues to recover or if there is a dramatic decline in ice coverage over the next 5 months. There are some newer models that have been developed and according to the NSIDS site the project, known as the SEARCH Sea Ice Outlook, has collected more than 300 predictions of summer month ice extent. A recent study published in Geophysical Research Letters by researchers at NSIDC, University of New Hampshire, and University of Washington reveal a large range in predictive skill. The predictions donít do so well if the ice coverage doesnít decline with the same rate as has been observed over the past few decades.
Median (red) and interquartile range (gray shading) of sea ice predictions submitted to the July SEARCH SIO each year compared with September mean sea ice extent (green).
Credit: Stroeve et al.
This year you can also follow the normal summer melting that occurs on Greenland. The graph below show the average amount of melt for that land mass and where 2014ís melting is almost up to the current day.
All this information can be a bit overwhelming and turn the planets cycles into some sort of reality show for the climate. However, I do think itís important to be able to observe changes to the Earth and then hopefully we can understand how these changes fit into the bigger picture of climate change and what affects anthropogenic (human) forcing may or may not be playing in them.
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