Declining Arctic Sea Ice

As most of you know, Arctic sea ice has been declining.The top graph shows a decline
in the late summer ice extent from around an average of 11 million square kilometers
average in the first one-half of the 20th century to around an average of 6 million sq.
km in the 2000-2010 time frame. The second graph shows the late summer Arctic sea
ice extent in the 5.5 to 7.5 million sq. km range for the years 1981 to 2010 and the
Arctic sea ice averaging around 5.0 million sq. km from 2015 through 2018.
The bottom graph shows that 2012 was a record your for minimum Arctic sea ice extent and 2019 is on pace to rank just behind 2012.

Why is this important? The ocean has a typical albedo of 0.06 (6% of the incoming energy is reflected, the rest absorbed). Bare sea ice has an albedo of 0.6 +/- 0.1 (60% of the energy is reflected). The earth is absorbing more of the sun's energy as the ice melts
and that causes more ice to melt with the reflectivity declining further in a positive feedback loop. Greenland will melt at a faster rate as the Arctic sea ice disappears. The declining
temperature differential between the Arctic and the equator weakens the jet stream
which may contribute to more extreme weather in the mid-latitudes but this is a controversial topic at the present time and too complex to discuss. There is also the
adverse effects on wildlife.



Figure 1: Average July through September Arctic sea ice extent 1870-2008 from the University of Illinois (Walsh & Chapman 2001 updated to 200 and observational data from NSIDC for 2009-2011 (blue), with a fourth order polynomial fit (black soiid line). Black vertical dashed lines indicate the years 1938-43. (from skepticalscience.com)




Figure 2a. The graph above shows Arctic sea ice extent as of August 14, 2019, along with daily ice extent data for four previous years and the record low year. 2019 is shown in blue, 2018 in green, 2017 in orange, 2016 in brown, 2015 in purple, and 2012 in dotted brown. The 1981 to 2010 median is in dark gray. The gray areas around the median line show the interquartile and interdecile ranges of the data (from the National Snow and ice Data Center)


(from the National Snow and Ice Data Center)

 

I forgot to mention that the sea ice is getting thinner by a significant amount.

 

Arctic ice has been keeping the temperature of the oceans and atmosphere close to 0 degrees C. Without that ice, warmer water will melt the sub-sea permafrost and warmer winds will
increase the melting rate of Greenland's ice. Melting permafrost will lead to the release of methane and that is currently happening now. Methane release along with decreasing albedo
are 2 positive feedbacks and increasing water vapor over the Arctic (because warm air can hold more water vapor which is a greenhouse gas) is another positive feedback. A fourth
positive feedback involves warmer north-flowing rivers in Canada and Siberia bringing warmer water into the Arctic ocean. This is why the polar ice caps are often called the earth's
air conditioner.

 

It’s at the same level as the 30’s. It’s controlled by ocean currents.

 

We have the Danish ice maps from the 30s, and they show much, much more Arctic sea ice. As usual, your claim is fictional.

 

Ice maps from the 30’s mean nothing.

The records we have start in 1979 when satellites started measuring. This year isn’t the lowest, 2012 was.

 

Posted previously:

https://www.academia.edu/35571845/D...h_the_most_extensive_peer_reviewed_references

 

That's a propaganda piece which is cherrypicking snippets from various papers, not a primary source.

And I looked at the primary source it referenced. It didn't say anything about sea ice levels in the 1930s. The paper does say there was a warm period in the Arctic in the 1930s, and that it was warmer than the 1990s .... but then, it's gotten much warmer in the Arctic since the 1990s. Not very honest for your propaganda source to fail to mention that.

Here's a primary source. The sea ice extent in August 1932 is way bigger than sea ice extinct in August 2019.

 

If your kneejerk response to data you don't like is to dismiss that data, that paints you as a pseudoscience devotee. Real scientist don't handwave away inconvenient data.

 

Propaganda ???

 

Yes, the Danes in 1932 were clearly part of the VastSecretGlobalSocialistPlot. It goes back that far .Congratulations on being one of the few elite courageous souls who grasps the RealTruth, unlike all the other sheeple out there.

 

There you go again.

 

Makes you wonder why Obama bought a $15 million dollar house on an island, and then some moron insured it huh.

 

Somehow you think ship reports are the same as satellite coverage.

 

Alarmists splice together bits and pieces of "data" which supports their faith based narrative. "Hiding the Decline" is a great example.

 

Throwing away any inconvenient data is the telltale action of a pseudoscience devotee

You and Hoosier8 automatically throw away all inconvenient data, purely as a reflex action. Your pseudoscience cult has trained you to do that.

 

Read “Hiding the Decline” and get back to us.

 

I'm aware of your cult's dishonesty and fraud there. What specific denier fraud did you want to highlight?

 

Thanks for the laugh.

 

If they are interpreted a certain way. We KNOW that Arctic sea ice was much less in the Medieval Warm Period, because the Vikings were able to settle Greenland and even farm it.

Nope. We also have the indisputable historical fact that the small Canadian research vessel St Roch was able to navigate the Northwest Passage in one season in 1944, a feat never achieved before and not repeated for another decade. Canadian records show sea ice increasing from the 1940s to the 1970s, by which time only huge icebreakers like the Manhattan could make it through.

 

Another example of the benefits of global warming. The alarmists wish that the Northwest Passage remain closed to commercial shipping.

 

True. One might take their nonsense seriously if commercial shipping ever starts routinely using the Northwest Passage in the summer months without icebreakers. Money talks louder than cherry-picked data. So far, not a peep...

 

Not your way, as your way is to reflexively deny any hard data that contradicts your cult's religious beliefs.

That makes no sense. Southern Greenland never has sea ice around it, not even in winter, not even in the highest ice years conditions. Even if it were deep freeze conditions, the Vikings could still reach Greenland.

And no, the Vikings didn't "farm". At best, they grew a bit of barley in valley bottoms. It was too cold to farm. It is much warmer in Greenland now than it was during the MWP. Actual farming can be done in Greenland now, and real trees can be grown.

The fact that a vessel (heavily ice-strengthened, and still nearly crushed) could slip through in 1940 has no bearing on whether Arctic sea ice is decreasing rapidly now. It is.

No, you just made that up.

Explain it too us. How does the lack of commercial shipping, which nobody predicted any time soon, prove anything except that you tend to fail hard at using reason?

 

He says without being able to outline anything that was thrown away other than the hysteria based on propaganda from the folks that have no clue about science such as yourself.

 

The alarmists have a redefinition for that too.