We are currently upgrading our site. You may experience some hiccups with certain features during that process.

Arctic climate change: the past 100 years

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

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.

Reader Comments

Comments will take a few seconds to appear.

Post Your Comments

Please sign in to post comments.

Sign In or Register Sign In or Register

Not only will you be able to leave comments on this blog, but you'll also have the ability to upload and share your photos in our Wunder Photos section.

Display: 0, 50, 100, 200 Sort: Newest First - Order Posted

Viewing: 303 - 253

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7Blog Index

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: 13857
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: 3684
301. Thunderstorm2
5:03 PM GMT on February 15, 2007
Neutral means in the middle
Member Since: December 22, 2006 Posts: 130 Comments: 7608
300. Thunderstorm2
5:02 PM GMT on February 15, 2007
Good Afternoon H23 and everyone else.
Member Since: December 22, 2006 Posts: 130 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: 3684
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: 13857
297. StSimonsIslandGAGuy
3:55 PM GMT on February 15, 2007
Burlington VT set a record for the snowiest day, the snowiest 24-hour period, the heaviest precipitation in a day (water equivalent) in the month of February) and the second highest total in a snowstorm with this storm.

What is kinda odd to me looking at the records there is that there had never been a really heavy snowstorm in February before. The previous heaviest snowstorm in FEb was 17.8 inches, and was 10th on their all time list. 25.5 inches fell yesterday, which is quite impressive for a place now downwind of a great lake or near the coast!
Member Since: July 7, 2005 Posts: 257 Comments: 21376
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: 3684
295. StSimonsIslandGAGuy
3:44 PM GMT on February 15, 2007
maybe there are more trees growing from being planted, but there are also a lot more being cut down.

Actually, he may be right since forest cover over the United States, western and central Europe, and China is increasing, while it decreases in South America, Africa and India/southeast Asia.

One of the neat things going on is that young growing forests pull carbon dioxide out of the atmosphere as their biomass increases (a mature forest is CO2 neutral) So the young growing forests in the USA are pulling out more than 1.5 billion tons of CO2 annually now. That is enough to make a difference, it offsets more than 10% of the CO2 emissions of the USA. As the forests mature, CO2 net absorbtion will decrease.

Assuming constant birth rates and immigration (illegal + legal) the population of the USA will rise from 301 million today to 953 million in 2100, with population rising by 10 million annually by that time. That population projections seems high to me. If anything fairly close to it takes place, I don't see how the USA can avoid net forest losses that raise CO2 emissions, AND think of all the cars and air conditioning that people will use!
Member Since: July 7, 2005 Posts: 257 Comments: 21376
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: 13857
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: 2 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.
291. StSimonsIslandGAGuy
4:32 AM GMT on February 15, 2007
Temperature records go back a lot further than that, we have accurate readings going back thousands of years, from ice core readings, and highly resolved records from the last few millenia in ice sheets. The world as a whole was actually warmer 4-6 thousand years ago, in the Holocene optimum. It was almost as warm in the medieval warm period (it was warmer in northwestern Europe 1000 years ago than today, although other parts of the globe were cooler, so the average global temperature was not quite as warm) The point is that we have already increased the concentration of CO2 and methane far beyond any levels during the past 740,000 years of ice core readings. The projected increases in fossil fuel consumption (especially coal) will continue to cause rising concentrations of CO2 in the air at an accelerating rate. 500 ppm and 600 ppm concentrations are assured, and they may well go higher than that. The world will warm as a result, and the possibility of feedbacks, such as clathrate releases or methane releases from the boreal forestsor increased heat retention from smaller snowpacks and sea ice fields are very real, even if no one is *SURE* how those feedbacks will play out, or if there are others no one has thought of yet.

Another point is that global warming will not stop at 2100. The high CO2 concentrations will continue to cause temperatures to rise by several degrees in the century after that. And the century after that. And the century after that. Small reductions in the growth rates of emissions in the short term, and gradual future reductions in emissions in the long term, can have large effects in where the CO2 concentrations at the end of the century end up

Although I personally believe that India and China's coal use will probably send us into catastrophic global warming in centuries to come, I could well be wrong, and we should work to try to limit emissions--and to encourage developing countries to develop energy resources in more efficient ways and that produce lesser emissions. Reducing emission growth from business as usual could well provide critical time for us to adapt to a greenhouse world.

We are running a huge planetary experiment in which we will soon double CO2 concentrations above any in the last million years, and have already almost tripled methane concentrations. This will greatly increase the amount of heat trapped at the surface and in the atmosphere. How specific negative and positive feedbacks will play out is not known with certainty, but it is almost certain that the world will be profoundly changed, and not for the better. The world as it has been has been good for mankind. Our succeeding generations will not be so fortunate.
Member Since: July 7, 2005 Posts: 257 Comments: 21376
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: 13857
288. StSimonsIslandGAGuy
2:24 AM GMT on February 15, 2007
Look at how the waves went up at the buoy just east of Boston. They were less than a foot last night at 2 am!

Link
Member Since: July 7, 2005 Posts: 257 Comments: 21376
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: 12479
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: 12479
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: 3684
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: 130 Comments: 7608
279. JFLORIDA
9:27 PM GMT on February 14, 2007
We were supposed to be 62 today but its 66 now. And the pressure is dropping a bit. I think this system is stalled.

Wow - on the NWS forecast sprinkles just popped up tomorrow. Yay!
Member Since: May 22, 2006 Posts: 188 Comments: 24743
278. StSimonsIslandGAGuy
9:19 PM GMT on February 14, 2007
well it should be getting cooler in FL soon, that is gonna be a shivering snake!
Member Since: July 7, 2005 Posts: 257 Comments: 21376
277. JFLORIDA
9:10 PM GMT on February 14, 2007
Ok now - I was out working in my garden and went to turn on the water and got a shock because a Snake was out sunning himself.

So as the locals say The Snakes, they are a crawling today witch usually is mid to late April -- sometimes in very warm years March but - Ive never seen them out feb 14!!!!!!

The super low seems to have stalled and low pressure IS officially building in west Texas - Look for a revision in the forecasts - hopefully I will get rain out of it!
Member Since: May 22, 2006 Posts: 188 Comments: 24743
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: 13857
274. hurricane23
7:41 PM GMT on February 14, 2007
Visible imagery of the meteosat-7.



Member Since: May 14, 2006 Posts: 8 Comments: 13857
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
271. JFLORIDA
7:10 PM GMT on February 14, 2007
The two large lows are coming into phase in the NE.

Its not really showing up on the models(yet) but a system seems to be taking shape in west Texas. I wonder why it isnt registering in the forecasts??

The models, GFS at least, seem to have a high building there.

The Campeche swirl is there again today. I love that little thing. Look at the intersecting lines - it seems to be connected to every major frontal system in north America - like a pivot or something.

Theres an area off Texas that looks interesting too.
Member Since: May 22, 2006 Posts: 188 Comments: 24743
270. StSimonsIslandGAGuy
7:09 PM GMT on February 14, 2007
Montauk at 2 pm has a pressure of 28.92 (979.2 mb) and calm winds. Must be at the center!
Member Since: July 7, 2005 Posts: 257 Comments: 21376
269. Thunderstorm2
7:09 PM GMT on February 14, 2007
Another upcoming cyclone for the indian ocean
Member Since: December 22, 2006 Posts: 130 Comments: 7608
268. HadesGodWyvern
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: 59 Comments: 53195
267. StSimonsIslandGAGuy
6:41 PM GMT on February 14, 2007
The low center appears to be tracking a little further west than expected, currently heading west of buoy 44025.
Member Since: July 7, 2005 Posts: 257 Comments: 21376
266. StSimonsIslandGAGuy
6:30 PM GMT on February 14, 2007
Pressure also down to 28.97 (981 mb) at Montauk, NY
Member Since: July 7, 2005 Posts: 257 Comments: 21376
265. StSimonsIslandGAGuy
6:26 PM GMT on February 14, 2007
Pressure down 5.9 mb in last hour at Nantucket.
Member Since: July 7, 2005 Posts: 257 Comments: 21376
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: 439 Comments: 137186
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: 130 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: 130 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: 13857
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: 130 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: 439 Comments: 137186
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: 13857

Viewing: 303 - 253

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7Blog Index

Top of Page

Dr. Jeff Masters' WunderBlog

About

Dr. Masters co-founded wunderground in 1995. He flew with the NOAA Hurricane Hunters from 1986-1990. Co-blogging with him: Bob Henson, @bhensonweather

Local Weather

Light Snow
32 °F
Light Snow Mist

JeffMasters's Recent Photos

Afternoon clouds over Southwest Puerto Rico
Storm clouds gathering over Half Dome
Sierra snow
snowman at Yosemite Falls