Forgot Password?
Written by Miranda Huey   
Share |
Sunday, 31 January 2010

Sea Ice

Why is sea ice disappearing so quickly? Climatologists and global warming experts knew that global warming was going to melt ice sheets around the world, but they never predicted it would be this fast. The most dramatic examples of ice loss so far have been the Arctic Ocean and Antarctic Ocean. Why would it be in those places? It has to do with just being in the ocean.

In the Arctic, researchers have discovered an interesting ice phenomenon. Although most ocean waters are turbulent, the waters near large ice masses are generally calm, since ice will act as a buffer, dampening most waves into flatness. However, as the summer ice disappears, the waters around the Arctic are becoming more and more like the waters around other areas of the ocean. Unfortunately, that means that the warmer waters underneath are mixing up into the surface, potentially accelerating the ice melt.1

To make matters worse, there could be another reason the Arctic is warming so fast. Ice is naturally reflective, easily apparent by its bright white color.2 About 80% of the sunlight bounces off the surface into the atmosphere, keeping the ice cool.3 As the ice melts, open areas of ocean water become exposed to the sun. Since ocean water is choppy, it’s fairly dark,4 and absorbs about 90% of the sunlight that hits it.5 As the water gets hotter, the surrounding ice melts faster, creating a feedback loop of continually faster and faster melting of the ice.6 These two processes could help to explain why Arctic temperatures are 9 degrees Fahrenheit above what scientists had projected.

In the Antarctic, massive ice loss has also shattered scientific assumptions. One of Antarctica’s giant glaciers is melting at a rate four times faster than scientists had previously thought.7 But, surprisingly enough, most of Antarctica’s ice loss is not due to melting of the ice. In fact, it’s actually melting slower than previously expected. That’s because the Antarctic mostly melts in the summer, while the increase in temperature has taken place mostly during the winter and spring.8 The reason for that, scientists suspect, is because of the hole in the ozone layer, which creates stronger circumpolar winds, cooling the region.9

Then why exactly is the Antarctic losing ice so quickly? Instead of melting, as in the Arctic, ice is breaking off ice shelves and falling into seawater. While the reason behind this is baffling most scientists,10 a few scientists have come up with a working theory: a phenomenon called “infragravity waves.” Infragravity waves are essentially storm waves that have bounced off coastal waters, forming elongated waves that can “echo” off landmasses for thousands of miles. Ice shelves, which can be up to 1,000 feet thick, are normally unaffected by ocean waves, but these elongated infragravity waves are large enough to lift entire ice shelves an up to an inch. Unfortunately, if global warming increases the number of storms around the world, this process may only accelerate, breaking apart the ice even faster.11

Ironically, the melting of the Arctic may be a boon for oil and natural gas explorers. About a quarter of the earth’s unused fossil fuels are estimated to be under the Arctic shelf. Even worse for the environment, the melting Arctic could cause Russia’s large permafrost areas to melt, potentially releasing immense amounts of methane gas.12 The melting Arctic sea ice could accelerate the melting of Greenland’s ice, which would substantially contribute to rising sea levels.13

The most direct victims of ice loss in the Arctic and Antarctic are the animals that live there. In the Arctic, the shrinking habitats are putting a large ecological strain on well-known species such as the beluga whale, arctic foxes, wolverines, and polar bears.14 In the Antarctic, the ice loss has reduced the populations of the emperor penguin, Adélie penguin,15 the Blue Whale, the Humpback Whale, and the Antarctic minck whale.16

The good news is that ocean waves aren’t affecting the glaciers on land. On the other hand, even the relatively small reductions in land glaciers have a much larger and more direct impact on human activity. Decreasing snowpack in land glaciers is still reducing freshwater sources worldwide. In the Himalayas, for example, 90% of the glaciers are melting, creating a potential threat to food security and basic water supplies for over 2 billion people.17

Scientists now predict that the Arctic sea ice could disappear within a few decades.18 However, even if all the sea ice in the world melted, sea levels would rise only by about 4 millimeters.19 The real problem is that the higher temperatures from melting sea ice could facilitate polar land ice melting into the ocean. If Greenland’s ice sheets melted entirely, sea levels would rise another 20 feet, and if Antarctica’s ice sheets melted entirely, sea levels would rise 189 feet.20 Fortunately, the next century or so would only see a small portion of these major ice sheets.21,22 For the sake of endangered animals and humans alike, hopefully these trends can be reversed by strong international action addressing climate change.

Browse all Greeniacs Articles Browse all Greeniacs Guides        Browse all Greeniacs Articles
_______________________________________________________________________________

1 http://www.msnbc.msn.com/id/34706785/ns/us_news-environment/
2 http://abcnews.go.com/Technology/wireStory?id=7245387
3 http://science.howstuffworks.com/arctic-ice.htm
4 http://abcnews.go.com/Technology/wireStory?id=7245387
5 http://science.howstuffworks.com/arctic-ice.htm
6 http://abcnews.go.com/Technology/wireStory?id=7245387
7 http://www.timesonline.co.uk/tol/news/environment/article6797162.ece
8 http://www.newscientist.com/article/dn18364-why-antarctica-isnt-melting-much--yet.html
9 http://www.tnr.com/blog/the-vine/hot-and-cold
10 http://www.climateark.org/shared/reader/welcome.aspx?linkid=71133
11 http://www.msnbc.msn.com/id/34638036/ns/technology_and_science-science/
12 http://science.howstuffworks.com/arctic-ice1.htm
13 http://www.wunderground.com/blog/JeffMasters/comment.html?entrynum=1177
14 http://www.worldclimatereport.com/index.php/2007/05/02/arctic-ice-and-polar-bears/
15 http://www.greenpeace.org/international/campaigns/
    climate-change/impacts/global_melting/arctic_antarctic
16 http://www.redorbit.com/news/science/1442423/southern_
    whales_threatened_by_melting_antarctic_ice/
17 http://www.enn.com/press_releases/3205
18 http://www.guardian.co.uk/environment/2009/oct/15/arctic-survey-ice-melting
19 http://www.wunderground.com/blog/JeffMasters/comment.html?entrynum=1177
20 http://www.scientificamerican.com/article.cfm?id=arctic-ice-melts-cause-rising-sea
21 http://www.wunderground.com/blog/JeffMasters/comment.html?entrynum=1177
22 http://www.npr.org/templates/story/story.php?storyId=102066621




Add your comment
RSS comments

Only registered users can write comments.
Please login or register.

Click here to Register.  Click here to login.
Last Updated ( Wednesday, 26 October 2011 )

SEARCH GREENIACS.COM

Green Facts

  • In California homes, about 10% of energy usage is related to TVs, DVRs, cable and satellite boxes, and DVD players.

  • You will save 100 pounds of carbon for each incandescent bulb that you replace with a compact fluorescent bulb (CFL), over the life of the bulb.

  • Turning off the tap when brushing your teeth can save as much as 10 gallons a day per person.

  • Americans throw away enough aluminum to rebuild our entire commercial fleet of airplanes every 3 months

  • Bamboo absorbs 35% more carbon dioxide than equivalent stands of trees.

  • The World Health Organization estimates that 2 million people die prematurely worldwide every year due to air pollution.

  • American workers spend an average of 47 hours per year commuting through rush hour traffic. This adds up to 23 billion gallons of gas wasted in traffic each year.

  • States with bottle deposit laws have 35-40% less litter by volume.

  • 77% of people who commute to work by car drive alone.

  • Recycling 100 million cell phones can save enough energy to power 18,500 homes in the U.S. for a year.

  • Nudge your thermostat up two degrees in the summer and down two degrees in the winter to prevent 2,000 pounds of carbon dioxide from entering the atmosphere.

  • A steel mill using recycled scrap reduces related water pollution, air pollution, and mining wastes by about 70%.

  • One recycled aluminum can will save enough energy to run a 100-watt bulb for 20 hours, a computer for 3 hours, or a TV for 2 hours.

  • Washing your clothes in cold or warm instead of hot water saves 500 pounds of carbon dioxide a year, and drying your clothes on a clothesline six months out of the year would save another 700 pounds.

  • Every week about 20 species of plants and animals become extinct.

  • Less than 1% of electricity in the United States is generated from solar power.

  • Recycling for one year at Stanford University saved the equivalent of 33,913 trees and the need for 636 tons of iron ore, coal, and limestone.

  • You will save 300 pounds of carbon dioxide for every 10,000 miles you drive if you always keep your car’s tires fully inflated.

  • Rainforests are being cut down at the rate of 100 acres per minute.

  • You’ll save two pounds of carbon for every 20 glass bottles that you recycle.

  • Americans throw away more than 120 million cell phones each year, which contribute 60,000 tons of waste to landfills annually.

  • An aluminum can that is thrown away instead of recycled will still be a can 500 years from now!

  • A single quart of motor oil, if disposed of improperly, can contaminate up to 2,000,000 gallons of fresh water.

  • Americans use 100 million tin and steel cans every day.

  • 82 percent of greenhouse gas emissions in the U.S. come from burning fossil fuels.

  • Plastic bags and other plastic garbage thrown into the ocean kill as many as 1,000,000 sea creatures every year.

  • A laptop consumes five times less electricity than a desktop computer.

  • Shaving 10 miles off of your weekly driving pattern can eliminate about 500 pounds of carbon dioxide emissions a year.

  • A tree that provides a home with shade from the sun can reduce the energy required to run the air conditioner and save an additional 200 to 2,000 pounds of carbon over its lifetime.

  • Due to tiger poaching, habitat destruction, and other human-tiger conflicts, tigers now number around 3,200—a decrease in population by about 70% from 100 years ago.

  • Recycling 1 million laptop computers can save the amount of energy used by 3,657 homes in the U.S. over the course of a year.

  • For every 38,000 bills consumers pay online instead of by mail, 5,058 pounds of greenhouse gases are avoided and two tons of trees are preserved.

  • Current sea ice levels are at least 47% lower than they were in 1979.

  • Recycling aluminum saves 95% of the energy used to make the material from scratch.

  • Glass can be recycled over and over again without ever wearing down.

  • If every U.S. household turned the thermostat down by 10 degrees for seven hours each night during the cold months, and seven hours each weekday, it would prevent nearly gas emissions.

  • In the United States, automobiles produce over 20 percent of total carbon emissions. Walk or bike and you'll save one pound of carbon for every mile you travel.

  • It takes 6,000,000 trees to make 1 year's worth of tissues for the world.

  • Refrigerators built in 1975 used 4 times more energy than current models.