Arctic Ice May Melt By 2040

Dekortage writes in with a new study by the National Center for Atmospheric Research suggesting that the North Pole may be clear of ice in summer as soon as 2040, decades earlier than previously thought. From the article: "'As the ice retreats, the ocean transports more heat to the Arctic and the open water absorbs more sunlight, further accelerating the rate of warming and leading to the loss of more ice,' Holland said in the statement. 'This is a positive feedback loop with dramatic implications for the entire Arctic.'"

Comments

Re:No change in sea level.

[hal2814]

"it actually LOWERS the water level."

Wrong again. The volume of the ice submerged in the water is equal to the volume of the ice if it were water. The only difference between the water and the ice is density. Ice is less dense. Because of that, it floats. But the only part of the ice that floats above the water line is the difference in volume between it's forzen and melted states. Submerged ice melting in water leaves the water level at exactly the same place. It's not a centimeter, millimeter, or even nanometer different. It physically can't be different.

Re:Sea Level?

[Qzukk]

You can try this yourself with a glass of water and ice cubes. Mark the water line with the ice cubes floating, then let the ice melt and notice that it hasn't moved. This is elementary school physics.

And by the time you get to college, you should have learned that the experiment does not work with saltwater.

Re:No change in sea level.

[RingDev]

My ability to work formulas and functions far exceeds my ability to express those formulas in the english language. ;) So here's a picture of what I was attempting to express.

Ice
~~~ = No change in sea level (or extremely small change)
Ice

Ice
~~~ = Increase in sea level
Land

-Rick

Re:No change in sea level.

[sadtrev]

A few reasons why this is significant

1. not all the ice that could melt is supported by water buoyancy.
2. temperature changes of liquid water will cause change in density.
3. polar bears will drown

The first is what could inhibit the Atlantic Conveyor by weakening its motive force : the downward flow of cooled salty water would be disrupted by large quantities of freshwater runoff from Greenland. Consequence - European weather becomes more like that on Newfoundland.
The second mechanism is what will cause sea levels to rise - the average temperature of the ocean is more than 4C so an uniform increase in water temperature will cause expansion. As the ocean is quite deep in places, a small expansion could lead to a significant rise in water level.
Admittedly not everybody cares about polar bears drowning or European climate becoming too cold to make Champagne or low-lying island states in the Indian Ocean being obliterated. Selfish gits.

Re:No change in sea level.

[Climate Shill]

I've been following global warming for a long time now doing a lot research on the side for the last couple of years. Here are some facts about global warming. Some of which you hear and don't hear from the main stream media: 1.) The world appears to be getting warmer with many computer models showing an increase in global temperature.

The word you're looking for here is "thermometers".

3.) Apparently, the Earth magnetic field has decreased by 10% in the last 150 years (source: http://www.space.com/scienceastronomy/earth_magnet ic_031212.html). I'm an electrical engineer and during my studies in particle physics, I learned that a particles velocity can be affected by magnetic fields. I believe it's possible that more of the Sun's radiation is penetrating the Earth's magnetic field due to it being weaker. If more radiation hits the Earth, shouldn't that also increase the overall temperature of the Earth and can global warming be attributed to this?

No, obviously not. The temperature was falling throughout those 150 years and has only started rising recently. The only correlated factor is CO2.

4.) Jupitor is experiencing the same climate change that Earth is. (source: http://www.space.com/scienceastronomy/060504_red_j r.html [space.com])

5.) Mars is experiencing the same climate change that Earth is. (source: http://www.space.com/scienceastronomy/solarsystem/ mars_snow_011206-1.html and http://www.dailymail.co.uk/pages/live/articles/new s/news.html?in_article_id=410901&in_page_id=1770)

Complete crap. We have absolutely no idea what the temperature history of the other planets is and so we have no way of drawing any conclusions from any changes we see.

6.) The United Nations found that there is more Methane produced from livestock, which raises global temperature greater than CO2 by a factor of approx. 20, than any human caused CO2 combined (source: http://www.fao.org/newsroom/en/news/2006/1000448/i ndex.html)

The article you linked to says that CH4 only amounts to 18% of CO2-equivalent emissions. Since the lifetime of CH4 is only 12 years, the cumulative effect is smaller still.

How can you explain the recent same climate changes on different planets? I doubt it's all those cars being driven there.

See above. However, since temperatures on Earth have only started rising recently, and we've been monitoring the Sun's output longer than that, we can be sure the reason isn't a change in the Sun.

Is it possible that the warmer temperatures that Earth is experiencing are caused by cyclical natural phenomena? What about glaciers in Greenland that have been shrinking for 100 years (source: http://www.breitbart.com/news/2006/08/21/060821191 826.o0mynclv.html [breitbart.com])? Also, how do you explain huge ice ages on Earth? Were thse caused by huge carbon emissions or was it a small natural climate cycle that just happens? Were those climate changes, which are no doubt more extreme than what's going on now, caused by the combustion engine? I don't have answers and everyone seems to have an opinion including a Nobel laureate who says the answer is more pollution (source: http://www.cnn.com/2006/TECH/science/11/16/smog.wa rming.ap/index.h

It does change sea level... a little

[FhnuZoag]

Actually, no. Sea level will still rise: though only by a little. The water from the ice is less dense than the sea water around it because the sea ice typically contains less salt. Hence, more floats up above the water than bouyancy would suggest, which reduces the water level as it gets frozen, and increases the water level when the ice melts again.

Search for 'salinity' in http://www.radix.net/~bobg/faqs/sea.level.faq.html

Once again... hacking the papers

[OUWxGuesser]

Here's the full abstract. Note that 1 of 7 computer models showed total ice melt by 2040... the worst case scenario. Gotta love how the media grabs the flashy stuff. Holland, Marika M.; Bitz, Cecilia M.; Tremblay, Bruno Future abrupt reductions in the summer Arctic sea ice Geophys. Res. Lett., Vol. 33, No. 23, L23503 http://www.agu.org/pubs/crossref/2006/2006GL028024 .shtml Abstract We examine the trajectory of Arctic summer sea ice in seven projections from the Community Climate System Model and find that abrupt reductions are a common feature of these 21st century simulations. These events have decreasing September ice extent trends that are typically 4 times larger than comparable observed trends. One eventexhibits a decrease from 6 million km2 to 2 million km2 in a decade, reaching near ice-free September conditions by 2040. In the simulations, ice retreat accelerates as thinning increases the open water formation efficiency for a given melt rate and the ice-albedo feedback increases shortwave absorption. The retreat is abrupt when ocean heat transport to the Arctic is rapidly increasing. Analysis from multiple climate models and three forcing scenarios indicates that abrupt reductions occur in simulations from over 50% of the models and suggests that reductions in future greenhouse gas emissions moderate the likelihood of these events.