Arctic climate change: the past 100 years

By: Dr. Jeff Masters , 1:56 AM GMT on February 12, 2007

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The Arctic is a region particularly sensitive to climate change, since temperatures are, on average, near the freezing point of water. Slight shifts in the average temperature can greatly change the amount of ice and snow cover in the region, due to feedback processes. For example, as sea ice melts in response to rising temperatures, more of the dark ocean is exposed, allowing it to absorb more of the sun's energy. This further increases air temperatures, ocean temperatures, and ice melt in a process know as the "ice-albedo feedback" (albedo means how much sunlight a surface reflects). The 20% loss in Arctic sea ice in summer since 1979 has given rise to concerns that this "ice-albedo feedback" has taken hold and will amplify until the Arctic Ocean is entirely ice-free later this century. Should we be concerned? Has the Arctic been this warm in the past and the sea ice survived? The answers are yes, and yes.



Figure 1. Annual average change in near surface air temperature from stations on land relative to the average for 1961-1990, for the region from 60 to 90° north. Image credit: The Arctic Climate Impacts Assessment (ACIA).

The past 100 years
The Arctic Climate Impact Assessment (ACIA), published in November 2004, was a uniquely detailed study of Arctic climate compiled by 300 scientists over three years. The study found that while temperatures in the Arctic have increased significantly since 1980 (Figure 1), there was also a period in the 1930s and 1940s when temperatures were almost as warm. If one defines the Arctic as lying poleward of 62.5° north latitude (Polyakov, 2003), the 1930s and 1940s show up being warmest period in the past 100 years. Looking at Figure 1, one cannot dismiss the possibility that temperatures in the Arctic oscillate in a 50-year period, and we are due for a cooling trend that will take temperatures below normal by 2030.

However, the period since 1980 was a time when the entire globe (except the bulk of Antarctica) warmed, and the 1930s and 1940s were not. Thus, the 1930s and 1940s warming in the Arctic is thought to be fundamentally different. Furthermore, the past 20 consecutive years have all been above normal in temperature, whereas during the 1930s and 1940s there were a few cooler than average years interspersed with the very warm years. A detailed breakdown by month and region of the 100-year history of Arctic temperatures was performed by Overland et al. (2004). They found no evidence of a 50-year cycle in Arctic temperatures, and concluded that the warming since 1980 was unique. However, they stopped short of blaming the recent warming on human-emitted greenhouse gases (anthropogenic forcing). The ACIA, though, concluded that humans were likely to blame for the recent Arctic warming, but not definitely:

It is suggested strongly that whereas the earlier warming was natural internal climate-system variability, the recent surface air temperature changes are a response to anthropogenic forcing. There is still need for further study before it can be firmly concluded that the increase in Arctic temperatures over the past century and/or past few decades is due to anthropogenic forcing."

This is the first in a series of five blogs on climate change in the Arctic that will appear every Monday and Thursday over the next two weeks. Next blog: The skeptics attack the ACIA report--and how the position of the pole star is indicative of Arctic climate change.

Also, be sure to visit our new Climate Change blog, written by Dr. Ricky Rood of the University of Michigan.

Jeff Masters

References

Overland, J.E, M.C. Spillane, D.B. Percival, M. Wang, H.O. Mofjeld (2004), "Seasonal and Regional Variation of Pan-Arctic Surface Air Temperature over the Instrumental Record", Journal of Climate, 17:17, pp3263-3282, September 2004.

Polyakov, V., et al. (2003), "Variability and Trends of Air Temperature and Pressure in the Maritime Arctic, 1875-2000", Journal of Climate, 16, 2067-2077.

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303. hurricane23
5:29 PM GMT on February 15, 2007
Sheri Whether there are Neutral or la nina conditions present they both favor good atmospheric conditions that will allow tropical developement across the basin.

To futher understand here are a few links that have been useful to me.

1-La nina and el nino resources
2-Madden-Julian Oscillation
3-CPC-MJO page
4-MJO-Research
Member Since: May 14, 2006 Posts: 8 Comments: 13841
302. catastropheadjuster
5:06 PM GMT on February 15, 2007
Please don't think I'm gripping I'm just wondering why Dr.M don't update his articles everyday like he does like in hurricane season? I've notice the same stuff is up for 3-5 days at a time. Or is it because there just not much to write about? Remember I am not gripping I'm just wondering. I don't want to get into any trouble.
Member Since: August 24, 2006 Posts: 21 Comments: 3683
301. Thunderstorm2
5:03 PM GMT on February 15, 2007
Neutral means in the middle
Member Since: December 22, 2006 Posts: 129 Comments: 7608
300. Thunderstorm2
5:02 PM GMT on February 15, 2007
Good Afternoon H23 and everyone else.
Member Since: December 22, 2006 Posts: 129 Comments: 7608
299. catastropheadjuster
5:02 PM GMT on February 15, 2007
OK H23 I know I'm gonna sound dumb but I gotta ask ok, What do neutral mean? Does neutral it don't inhibit or hibit the situation. I know what I'm trying to say it just want come out right. So do you understand what I'm saying.
Member Since: August 24, 2006 Posts: 21 Comments: 3683
298. hurricane23
4:51 PM GMT on February 15, 2007
Posted By: catastropheadjuster at 10:54 AM EST on February 15, 2007.

Good morning everyone. Hi H23. So does everyone thing La Nina is going to come into effect for hurricane season? And when might we see the conditions?

Right now the way i see it the POAMA model is forcasting anything form neutral conditions to la nina atleast threw the end of september.were basically looking at a more active season number wise this time around across the atlantic basin.There are alot of things yet to evolve like for example how will the all important steering currents set up?Or how will the SAL be around the basin remember that the Sal Factor was one of the main reasons that caused the 2006 season to be an average season with (10/5/2).Indeed alot of questions that we will probably not know the answer to for another couple of months.Also keep in mind a quite season can also be deadly it only takes one to ruin lives.1992 is a great example of that with andrew.Adrian

Here is graphic of the POAMA model.

CLICK ON THUMBNAIL


Graphic of models in pretty agreement of atleast Neutral threw the first half of the 2007 hurricane season.

See Graphic Here
Member Since: May 14, 2006 Posts: 8 Comments: 13841
296. catastropheadjuster
3:54 PM GMT on February 15, 2007
Good morning everyone. Hi H23. So does everyone thing La Nina is going to come into effect for hurricane season? And when might we see the conditions? Are we in Neutral conditions right know or is El Nino trying to hang in there? I know I'm full of questions this morning. Oh yeah I'm not trying to make anyone make aprediction I just figured I'd listen to what other folks where thinking that's all. Well I'll be reading in the back ground til someone wants to talk about it. I know it's a little to early to be talking about hurricane season but it don't hurt to wonder.
Member Since: August 24, 2006 Posts: 21 Comments: 3683
294. hurricane23
1:52 PM GMT on February 15, 2007
New invest in the NW pacific on the FNMOC site.Winds are curently at 15kts.



WFO Guam Sectors

FNMOC visible view

Member Since: May 14, 2006 Posts: 8 Comments: 13841
293. mrpuertorico
11:10 AM GMT on February 15, 2007
There are more trees growing now than any time in the last 200 years based on solid scientific data

I don't buy that show me the scientific data!
Today in the amazon deforestation is going at a rate of thousands of acres per day! Plus two hundred years ago we didn't have people cutting down the south american rain forest.
Member Since: July 10, 2006 Posts: 1 Comments: 833
292. john4truth
5:15 AM GMT on February 15, 2007
It is very difficult to find any true facts.. Statistics are being used to fulfill prejuced intentions. This not science. I do not deny we have hurt some parts of the enviroment. In many areas we have helped. There are more trees growing now than any time in the last 200 years based on solid scientific data. This is an extreme positive that is never factored in. The facts are not easy to find.
290. miamihurricane12
3:34 AM GMT on February 15, 2007
John I would say that you are half right...their is alot of politics involved and the main contributors (if true) are out of our control so why do they insist on feeding this information down our throats when it is the governments of the world that have the power to do something about GW. I think that we did not cause it but be have inhanced it. Now we have records dating back until the 1800's which is known as being a cooler period, so the fact that scientists seem to think that something like this has never happened before is ridiculous and irresponsible.
289. hurricane23
2:41 AM GMT on February 15, 2007
Looks like 14S has indeed gotten futher organized with deep convection now consolidating and looking more cymmetrical.Futher intensification seems likely.



Another view...




Member Since: May 14, 2006 Posts: 8 Comments: 13841
287. weatherboykris
1:48 AM GMT on February 15, 2007
Sorry john,but humans produce far more greenhouse gases than volcanoes.You may be right that GW is not human induced,but you're wrong to say we don't produce as many greenhouse gases as volcanoes.
Member Since: December 9, 2006 Posts: 125 Comments: 11346
286. john4truth
12:25 AM GMT on February 15, 2007
I am amazed by the chicken littles. History proves the temperatures go up and down and always have. Volcanos do more to produce greenhouse gas than man ever could. Saying man is responsible for global warming is false information. I do not believe everyone that blames man for changes in temperature are liars only that they are misinformed. Man is not to blame but if we listen to the nuts I guess the answer is destroy all animals and humans to stop the production of gas. This is all political nothing more nothing less.
285. ryang
12:15 AM GMT on February 15, 2007
Hey 12,yes.
Member Since: August 25, 2006 Posts: 329 Comments: 12453
284. miamihurricane12
12:14 AM GMT on February 15, 2007
so how cold do you think it is going to get this weekend in miami? will be go into the thirties or stay in the low 40's
283. ryang
10:54 PM GMT on February 14, 2007
Hello
Member Since: August 25, 2006 Posts: 329 Comments: 12453
282. catastropheadjuster
10:53 PM GMT on February 14, 2007
HURRICANE23: Are you still here? If you are you got WU-MAIL. Whenever you get a chance to read it.Have fun. I'm gonna hang around for a few to see if you answer if not I'll be back later.
Member Since: August 24, 2006 Posts: 21 Comments: 3683
281. jake436
9:59 PM GMT on February 14, 2007
High temp yesterday was near 70 degrees, high temp today, 45 degrees. I live 10 minutes south of Hattiesburg,MS. I noticed yesterday afternoon it was 74 in Mobile, and at the same time, 44 in Shreveport, LA. Quite a front, indeed.
Member Since: August 31, 2006 Posts: 0 Comments: 271
280. Thunderstorm2
9:32 PM GMT on February 14, 2007
Good evening Everyone
Member Since: December 22, 2006 Posts: 129 Comments: 7608
276. V26R
8:07 PM GMT on February 14, 2007
Looks like maybe a bit too much shear to let it rip
Member Since: July 20, 2006 Posts: 0 Comments: 1762
275. hurricane23
7:51 PM GMT on February 14, 2007
Animated view of 14S...



CLOSE-UP 1KM ON MODIS.

Member Since: May 14, 2006 Posts: 8 Comments: 13841
274. hurricane23
7:41 PM GMT on February 14, 2007
Visible imagery of the meteosat-7.



Member Since: May 14, 2006 Posts: 8 Comments: 13841
273. V26R
7:21 PM GMT on February 14, 2007
Pressure here in Staten Island is 29.17in
with a northerly wind
Member Since: July 20, 2006 Posts: 0 Comments: 1762
272. V26R
7:19 PM GMT on February 14, 2007
Oh great, With the cold air this thing is going to pull down, this one we will really get some snow!
Guess the old saying does apply, Snow Breads Snow!
Member Since: July 20, 2006 Posts: 0 Comments: 1762
269. Thunderstorm2
7:09 PM GMT on February 14, 2007
Another upcoming cyclone for the indian ocean
Member Since: December 22, 2006 Posts: 129 Comments: 7608
268. HadesGodWyvern (Mod)
7:08 PM GMT on February 14, 2007


Metro France might issue a Red Alert this weekend for Reunion if Favio can get up to CYCLONE tropicale status.
Member Since: May 24, 2006 Posts: 52 Comments: 46909
264. V26R
4:44 PM GMT on February 14, 2007
This thing is really winding up now
Pressure is dropping at 29.28 in
Link
Member Since: July 20, 2006 Posts: 0 Comments: 1762
263. Patrap
4:36 PM GMT on February 14, 2007
Be careful..ice bad stuff under fresh fallen snow.
Member Since: July 3, 2005 Posts: 428 Comments: 129841
262. Thunderstorm2
4:35 PM GMT on February 14, 2007
It was a rough night for everyone in the south and south east
Member Since: December 22, 2006 Posts: 129 Comments: 7608
261. V26R
4:35 PM GMT on February 14, 2007
You know I can tolerate the snow, but the Ice I really hate
Its easing off now, but Wind is really picking up, We're supposed to get about 2-3 inches of snow on the backside of this thing
Thats not going to be fun, Ice underneath Snow!
Member Since: July 20, 2006 Posts: 0 Comments: 1762
260. Thunderstorm2
4:32 PM GMT on February 14, 2007
There was damage-a-plenty down here after last nights storm
Member Since: December 22, 2006 Posts: 129 Comments: 7608
259. hurricane23
4:32 PM GMT on February 14, 2007
Looks nasty up there V26R good thing u stayed home.

New york Radar




Member Since: May 14, 2006 Posts: 8 Comments: 13841
258. V26R
4:31 PM GMT on February 14, 2007
And a Very Good Morning to you Sir!
Member Since: July 20, 2006 Posts: 0 Comments: 1762
257. V26R
4:30 PM GMT on February 14, 2007
Heard from a Cousin down in Marathon that they had Water Spout Warnings eary in the day
Don't know if they ever materialized
Member Since: July 20, 2006 Posts: 0 Comments: 1762
256. Thunderstorm2
4:27 PM GMT on February 14, 2007
Good Morning Everyone
Member Since: December 22, 2006 Posts: 129 Comments: 7608
255. V26R
4:27 PM GMT on February 14, 2007
You're smart not to have!
Still cannot understand these guys that you see on National Geographic and Discovery chasing them in their pickup trucks
Member Since: July 20, 2006 Posts: 0 Comments: 1762
254. Patrap
4:26 PM GMT on February 14, 2007
Thanks V36R..we were very fortunate..Many were not.But the warnings got out.
Member Since: July 3, 2005 Posts: 428 Comments: 129841
253. hurricane23
4:25 PM GMT on February 14, 2007
It really wasn't that bad across miami cloudy skies with some light rain.The florida keys saw incredible rain amounts with areas seeing up to 9-10 inches of rainfall.Had some friends calling on my cell telling me there cars were flooded down there.Amazing amounts.


Member Since: May 14, 2006 Posts: 8 Comments: 13841

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Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.

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