Monday, June 12, 2017

Shrinking Ice Caps, Rising Seas

The National Snow and Ice Data Center has created a series of interactive maps which visualize Satellite Observations of Arctic Change. The maps allow you to see how sea ice, snow cover and frozen ground have all been shrinking during the 21st Century. Other maps plot air temperature changes in the Arctic and the changes to Arctic vegetation.

Global warming is causing observable changes to ecological systems in the Arctic. Air temperatures in the Arctic are rising and sea ice extent is declining. Even Arctic vegetation is changing with tundra being replaced by shrubs.

Each of the NSIDC interactive maps uses NASA satellite data and research to plot changes to the Arctic from 1979 to 2015. The maps allow you to observe the data for each year in this period to observe how global warming has effected the ecological systems of the Arctic.

Mapbox has also released a map which allows you to view monthly Arctic sea ice changes all the way back to 1976 (when consistent satellite measurements began). Mapping Arctic Sea Ice uses data from the National Snow and Ice Data Center to show the sea ice cover for any month.

If you select a month from the timeline you can not only view the extent of the sea ice coverage for that month but also a line graph showing the total ice area in km2 and the temperature anomaly above the norm over time. The graph shows a clear trend of rising temperatures in the Arctic and a fall in the area of sea ice coverage.

The polar projection in the Arctic Sea Ice map was created with D3.js. You can easily create your own polar projection in Leaflet using Arctic Web Map,an Arctic specific web mapping tool, consisting of an Arctic-focused tile server. If you want to know how Mapbox created their polar projection then read the explanation below the map on the Mapbox blog.

MasterMaps has created another impressive mapped visualization of the Arctic ice cap. The Arctic Sea Ice map allows you to compare the monthly sea ice cover in the Arctic for any month since 2006.

If you select a month from the bottom timeline you can then adjust the year on the top timeline to make a direct comparison of any month for each year from 2006 to 2015. Every time you adjust the timeline the Arctic see ice coverage is automatically updated on the map. This map was also created with help from D3.js.

At the other end of the world Antarctica is also losing sea ice. Like nearly everything else glacial land ice obeys the law of gravity. Ice sheets therefore flow downhill. They normally do this very, very slowly. Unfortunately we don't live in normal times.

Global warming has warmed the oceans. Warmer oceans have undercut Antarctica's glaciers, causing them to flow quicker and quicker. With over 60% of the world's freshwater locked in Antarctica's ice this is a huge concern. If this ice melts we will see a global rise in sea level and coastal cities around the world will be in danger of inundation.

The New York Times has created a series of maps to help explain how global warming could lead to the melting of Antarctica's ice sheets and cause rising sea levels around the world. In Antarctic Dispatches glacier ice flow is beautifully illustrated in a series of animated maps. The danger of global rising seas is explained in maps showing areas of Antarctica that have lost ten feet or more of ice since 2010.

Part 3 of Antarctic Dispatches uses a scrolling map to help illustrate the amount of water locked up in Antarctica's ice sheets. The scale of the Ross Ice Shelf is illustrated by overlaying the route of the New York marathon on top of satellite imagery of the ice shelf. The Ross Ice Shelf is huge!

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