The Arctic

Arctic -1 Into the Arctic

I’m McKensie Daugherty, your host for On the Ocean. The effects of climate change on various regions of the planet have been getting a lot of media attention recently. The one area of Earth that is thought to be changing the fastest in response to global warming is the Arctic Ocean, which is the subject of this month’s show. The Arctic Ocean is the smallest of the world’s five oceans, encompassing only 3% of total ocean surface area and only 1% of total ocean volume. It is a nearly fully enclosed ocean basin, surrounded by North America, Greenland, Europe, and Russia on all sides, with only one small inlet from the Pacific Ocean and one outlet into the Atlantic Ocean. Thus, the Arctic Ocean is unique because once waters enter, they can stay in the Arctic, especially in the deep Arctic, for hundreds of years. One of the other special properties of the Arctic is that about 50% of its total area is composed of shallow regions called continental shelves that extend hundreds of kilometers out from the continents with an average depth of only 150 m. These shelf regions allow for significant exchange of Arctic seawater with continental sediments, rivers, and biological communities, which gives the Arctic a unique chemical composition. More importantly, however, these continental shelves become factories for the production of sea ice from Arctic seawater. This ice grows so much that about 93% of the surface Arctic becomes ice-covered each winter. This ice can reach several meters in thickness, and its snowy expanse is historically home to native Inuit communities and also large populations of seals, walruses, and the famous polar bears. This month we will talk about the real-time threat of climate change to Arctic communities and how Texas A&M University oceanographers are working to studying this rapidly changing ecosystem. This has been On the Ocean, a program made possible by the Department of Oceanography and a production of KAMU-FM on the campus of Texas A&M University in College Station. For more information and links, please go to ocean.tamu.edu and click On the Ocean.

Contributing Professor: Jessica Fitzsimmons

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Arctic Ocean map, with color showing water depth

credit: www.geology.com

Arctic 2- Arctic climate change

I’m McKensie Daugherty, your host for On the Ocean. This month we are discussing the Arctic Ocean, the region of the planet that is warming fastest in response to global climate change. Air temperatures in the Arctic Ocean have increased about 7°F in the last 50 years, which is the fastest temperature increase recorded anywhere on the planet, and around twice the global temperature rise. One of the most serious consequences of this temperature rise is the melting of Arctic sea ice, which traditionally covers most of the surface of the Arctic each winter. Ice thickness has decreased by 15% in the last 50 years, and the duration of winter ice coverage has decreased by more than 2 months annually. Staggeringly, sea ice extent has dropped 20% over the last 30 years alone. Not only do these changes affect the lives of people living in the North – for example, this year’s Iditarod sled race was forced to move its starting line 225 miles farther north due to lack of snow – but the organisms who make homes of these sea ice floes, such as polar bears, seals, walruses, and seabirds are finding their natural habitats shrinking significantly. However, there is another reason that the ice loss of Arctic sea ice is so dangerous to our planet. The melting of sea ice causes a climate feedback that actually encourages more melting. Sea ice has a low albedo, which means that the white color of the ice is very reflective of light and heat energy that reaches the Earth from the sun. This reflectivity helps to keep the Earth cool, but as global warming reduces sea ice extent, more heat is absorbed by the ocean waters that are uncovered by the ice, and this causes the planet to warm even faster. Thus, some scientists predict that this feedback loop could increase sea ice loss from 50% to a complete loss of summer sea ice by year 2100. This has been On the Ocean, a program made possible by the Department of Oceanography and a production of KAMU-FM on the campus of Texas A&M University in College Station. For more information and links, please go to ocean.tamu.edu and click On the Ocean.

Contributing Professor: Jessica Fitzsimmons

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Sea ice albedo climate change feedback (credit: Vancouver Observer)
ARCTIC OCEAN -- A polar bear is observed off Coast Guard Healy's port side Sept. 17, 2015 while underway in the Arctic Ocean.  Healy is underway in support of Geotraces, an international effort to study the distribution of trace elements in the world's oceans. U.S. Coast Guard photo by Petty Officer 2nd Class Cory J. Mendenhall.

ARCTIC OCEAN — A polar bear is observed off Coast Guard Healy’s port side Sept. 17, 2015 while underway in the Arctic Ocean.
Healy is underway in support of Geotraces, an international effort to study the distribution of trace elements in the world’s oceans. U.S. Coast Guard photo by Petty Officer 2nd Class Cory J. Mendenhall.

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Arctic sea ice coverage August 2015 (credit: Jessica Fitzsimmons)
Week Three: Freshwater effects of Arctic climate change

I’m McKensie Daugherty, your host for On the Ocean. This week we want to further highlight the freshwater impacts of rapid climate change in the Arctic, including both glacial melting and increased precipitation and river discharge into the Arctic basin. Glaciers are large bodies of ice with an average thickness of 7000 feet that build up from precipitation over cold land. Glaciers flow downhill over land towards the ocean, under their own weight. Arctic glaciers cover parts of Alaska, Canada, Greenland, Scandinavia, and Russia, with the second largest glacier in the world being the Greenland Ice Sheet. Since 1979, summer melt on the Greenland Ice Sheet has increased in surface area by 30%. Just the melting of Arctic glaciers alone is projected to result in sea-level rise of at least 5 cm by the year 2100, while total sea level rise by climate change over this century is projected to fall between 10-90 cm, depending on the rate of global temperature rise. Additionally, while the Arctic Ocean only encompasses 1% of total ocean volume, 10% of global river discharge flows into the mostly enclosed Arctic Ocean basin. The Arctic watershed, or land surface area over which freshwater from rain and snowfall converges into the Arctic via rivers and streams, is nearly double the surface area of the Arctic Ocean itself. With increasing Arctic temperatures, tropical moisture is predicted to move from the tropics toward the poles, resulting in increased net precipitation over the Arctic Ocean and watershed by nearly 20% by year 2100. This will result in greater river flow from the Arctic rivers directly into the ocean. This freshening of the Arctic Ocean is predicted to have a severely negative impact on global ocean circulation, which is currently driven by the sinking of very cold, partially Arctic-derived seawater in the polar North Atlantic. This has been On the Ocean, a program made possible by the Department of Oceanography and a production of KAMU-FM on the campus of Texas A&M University in College Station. For more information and links, please go to ocean.tamu.edu and click On the Ocean.

Contributing Professor: Jessica Fitzsimmons

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Arctic glacier (credit: marinebio.net)

Arctic -4 Texas A&M in the Arctic

I’m McKensie Daugherty, your host for On the Ocean. This year, Texas A&M oceanographers deployed to the Arctic Ocean as part of a multi-institution, multi-million dollar research initiative funded by the National Science Foundation through the International GEOTRACES program. The goal of the 65-day research cruise was to establish the most comprehensive understanding of the Arctic Ocean’s chemical composition ever recorded, with 51 scientists and 94 Coast Guard personnel deployed to the task. U.S. ships have only reached the true North Pole three times in history, with this research cruise aboard the world-class, U.S. Coast Guard icebreaking ship Healy, being the fourth. Due to thinning sea ice in recent years, the Healy was able to break the Arctic ice by itself, while in previous Arctic ventures at least two ships were required to supply sufficient power and fuel to break through the thick Arctic ice. Texas A&M oceanographers were aboard the Healy this year as it made history, becoming the first unaccompanied U.S. vessel to ever reach the true North Pole. The goals of the Arctic GEOTRACES cruise were to constrain chemical inputs to the Arctic Ocean from the Pacific, as well as explore the changing chemical inputs to the Arctic from rivers, sea ice, snow, and continental shelf sediments. Texas A&M scientists focused on measuring dissolved metal concentrations in Arctic seawater, snow, and ice. One metal of interest was iron, which is an important nutrient to planktonic plants that live in seawater and in Arctic sea ice. Another metal of interest was lead, which has a very minimal natural sources from continental rocks but has a growing concentration in the ocean from human sources such as fossil fuel combustion and coal burning, which is increasingly reaching the Arctic through human-influenced aerosol deposition. Though the Arctic is rapidly changing, this chemical inventory will serve as a baseline against which future change can be compared. This has been On the Ocean, a program made possible by the Department of Oceanography and a production of KAMU-FM on the campus of Texas A&M University in College Station. For more information and links, please go to ocean.tamu.edu and click On the Ocean.

Contributing Professor: Jessica Fitzsimmons

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US Arctic GEOTRACES aboard the USCGC Healy (photo credit: U.S. Coast Guard)
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Sample collection in the Arctic, US GEOTRACES (photo credit: U.S. Coast Guard photo by Petty Officer 2nd Class Cory J. Mendenhall)
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Aurora borealis (northern lights) abord the USCGC Healy (photo credit: U.S. Coast
Guard photo by Petty Officer 2nd Class Cory J. Mendenhall)