Arctic climate change: the past 100 years

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

Share this Blog
4
+

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¬į 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¬į 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.

or Join

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: 153 - 103

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

153. Thunderstorm2
6:19 PM GMT on February 13, 2007
urgent - immediate broadcast requested
Severe Thunderstorm Watch number 21
NWS Storm Prediction Center Norman OK
1255 PM EST Tue Feb 13 2007

The NWS Storm Prediction Center has issued a
Severe Thunderstorm Watch for portions of

central Florida
coastal waters

Effective this Tuesday afternoon and evening from 1255 PM until
700 PM EST.

Hail to 2 inches in diameter... thunderstorm wind gusts to 70
mph... and dangerous lightning are possible in these areas.

The Severe Thunderstorm Watch area is approximately along and 65
statute miles either side of a line from 20 miles north of Ocala
Florida to 50 miles east of fort Meyers Florida. For a complete
depiction of the watch see the associated watch outline update
(wous64 kwns wou1).

Remember... a Severe Thunderstorm Watch means conditions are
favorable for severe thunderstorms in and close to the watch
area. Persons in these areas should be on the lookout for
threatening weather conditions and listen for later statements
and possible warnings. Severe thunderstorms can and occasionally
do produce tornadoes.

Other watch information... continue... ww 20...

Discussion... tstm cluster off the W CST of FL... and additional
storms likely to from in heated environment over the interior... may
pose a threat for high wind and hail as region continues to
destablize downstream from 50 kt wly mid level jet streak. While
low level shear is weak over most of ww area... low level directional
shear will be enhanced invof E CST sea breeze boundary and outflows
from earlier storms. Part of watch number 21 along the immediate E
CST may require upgrade to tornado if it appears that discrete
storms will indeed interact with those boundaries.

Aviation... a few severe thunderstorms with hail surface and aloft
to 2 inches. Extreme turbulence and surface wind gusts to 60
knots. A few cumulonimbi with maximum tops to 450. Mean storm
motion vector 26035.


... Corfidi

;295,0811 270,0800 261,0820 291,0831


Member Since: December 22, 2006 Posts: 129 Comments: 7608
152. Thunderstorm2
6:18 PM GMT on February 13, 2007
I'm getting rain mist just now
Member Since: December 22, 2006 Posts: 129 Comments: 7608
151. Thunderstorm2
6:17 PM GMT on February 13, 2007
TAKE A LOOK AT THE STORMls
Member Since: December 22, 2006 Posts: 129 Comments: 7608
149. Thunderstorm2
6:12 PM GMT on February 13, 2007
Here it comes. Just got the alert on the news just now
Member Since: December 22, 2006 Posts: 129 Comments: 7608
147. Thunderstorm2
5:47 PM GMT on February 13, 2007
Thats bad news for me
Member Since: December 22, 2006 Posts: 129 Comments: 7608
144. Thunderstorm2
5:24 PM GMT on February 13, 2007
ls
Member Since: December 22, 2006 Posts: 129 Comments: 7608
143. Thunderstorm2
5:19 PM GMT on February 13, 2007
I'm watching it carefully here in Orlando
Member Since: December 22, 2006 Posts: 129 Comments: 7608
142. HIEXPRESS
12:16 PM EST on February 13, 2007
Heads-up: Storms approaching W Central Florida appear to have some strength & rotation. Line trailing S from this mornings LA storms overtaking, sun is out & getting warmer ahead - they could intensify.
Member Since: October 13, 2005 Posts: 4 Comments: 2156
141. Thunderstorm2
4:47 PM GMT on February 13, 2007
I've got a 75% chance of T-Storms today
Member Since: December 22, 2006 Posts: 129 Comments: 7608
140. Thunderstorm2
4:44 PM GMT on February 13, 2007
ok it's warm but i didn't know how warm it was for you
Member Since: December 22, 2006 Posts: 129 Comments: 7608
139. pottery
12:40 PM AST on February 13, 2007
.its 90 F here, but dry and windy. Fire weather. Got my fire trace cut last week, just in time I think. No chance of rain until June. Its going to be interesting......
Member Since: Posts: Comments:
138. Thunderstorm2
4:40 PM GMT on February 13, 2007
New Orleans seem to have bad luck at the moment
Member Since: December 22, 2006 Posts: 129 Comments: 7608
137. pottery
12:39 PM AST on February 13, 2007
...and more to come ??????
Member Since: Posts: Comments:
136. pottery
12:37 PM AST on February 13, 2007
..things look pretty nasty near new orleans again.
Member Since: Posts: Comments:
135. Thunderstorm2
4:37 PM GMT on February 13, 2007
i'm alright. it's a bit hot here,only 75
Member Since: December 22, 2006 Posts: 129 Comments: 7608
134. pottery
12:35 PM AST on February 13, 2007
I'm feeling very hot and dry here storm2, what about yerself ?
Member Since: Posts: Comments:
133. Thunderstorm2
4:34 PM GMT on February 13, 2007
Good Afternoon everyone. How are ya'll feeling?
Member Since: December 22, 2006 Posts: 129 Comments: 7608
132. pottery
12:27 PM AST on February 13, 2007
Re: Sen. Martinez letter, is the funding available ? Has it been cut ? What is the situation ? Does research continue to improve or not ?????????
Member Since: Posts: Comments:
131. 04gtp
4:26 PM GMT on February 13, 2007
Dear Dr. Masters:

Regarding your blog on the HRD research money being cut from NOAA's budget...here is the response from Florida Senator Mel Martinez, to an email of concern I sent him the other day:

Thank you for contacting me regarding the National Hurricane Research Initiative Act of 2006 (S. 4005). I appreciate hearing from you, and would like to take this opportunity to respond.

In the wake of the devastation wrought on the Gulf Coast in 2005 by Hurricanes Katrina, Rita, and Wilma, on September 29, 2006, I introduced bipartisan legislation to implement a national hurricane research initiative designed to better research, predict and prepare for hurricanes. This comprehensive proposal was crafted from the recommendations presented by the National Science Foundationís new draft report entitled, Hurricane Warning: The Critical Need for a National Hurricane Research Initiative. A coordinated research initiative is necessary given the enormous cost associated with hurricanes, in both dollars and human lives, combined with the fact that 90 percent of the nationís population lives within 200 miles of the coast.

S. 4005 will take the general recommendations from the National Science Foundationís report and assemble the expertise of our nationís science and engineering capabilities through a multi-agency effort that is focused on improving our understanding of hurricane prediction, intensity, and mitigation on coastal populations, infrastructure, and the natural environment. The bill sets out specific goals for research, including predicting hurricane intensification, storm surge, rainfall, and inland flooding, improved observations, assessment of vulnerable infrastructure, interaction of hurricanes with engineered structures, improved computational ability, improved disaster response and recovery, and evacuation planning. This legislation calls for gathered research to be formulated into a national and standardized database so that it may be put to use in real world situations through the creation of the National Hurricane Research Test Bed.

Florida and other Gulf Coast states have a lot at stake every hurricane season and there are still far too many unknowns. These unknowns carry great costs. Better, more intense, and more coordinated research can better help us prepare for the future.

Again, thank you for contacting me. If you have any additional questions or comments, please do not hesitate to contact me. In addition, for more information about issues and activities important to Florida, please sign up for my weekly newsletter at http://martinez.senate.gov.

Sincerely,

Mel Martinez
United States Senator


Member Since: Posts: Comments:
130. MisterPerfect
3:35 PM GMT on February 13, 2007
It looks like the arctic was colder when we were testing atomic/hydrogen bombs during the cold war. It seems the world has gotten hotter after successful attempts to reduce nuclear weapon proliferation the past two decades. If the graph above in the blog entry is correct, maybe supporters of global warming should initialize a nuclear winter? I can see Al Gore now, pushing for atmosphereic warhead detonation over Greenland...
Member Since: Posts: Comments:
129. Patrap
9:17 AM CST on February 13, 2007
Local info on damage Link
Member Since: July 3, 2005 Posts: 427 Comments: 129439
128. Patrap
9:16 AM CST on February 13, 2007
teresa here again.One word from Patrap now in ponchatrain park.."incredible"
Member Since: July 3, 2005 Posts: 427 Comments: 129439
127. MAXinNauvoo
2:54 PM GMT on February 13, 2007
How about the Anartic, Dr. Jim?
Member Since: Posts: Comments:
126. Patrap
8:42 AM CST on February 13, 2007
My alert Weather NOAA radio awoke me at 2am..with plenty of warning...thankfully.
Member Since: July 3, 2005 Posts: 427 Comments: 129439
125. catastropheadjuster
2:35 PM GMT on February 13, 2007
The weather here in Mobile is getting pretty bad to. It's as black as a ace of spades.
Member Since: Posts: Comments:
124. Patrap
8:25 AM CST on February 13, 2007
Ponchatrain Park near Lakeview..heavily flooded during Katrina..heavily damaged by this mornings Tornado...
Member Since: July 3, 2005 Posts: 427 Comments: 129439
123. Patrap
8:19 AM CST on February 13, 2007
Quick video from TV of Damage here..
Member Since: July 3, 2005 Posts: 427 Comments: 129439
122. Patrap
7:44 AM CST on February 13, 2007
One Fatality reported Tornado touches down in Westwego, Carrollton areas

Elderly woman killed in Pontchartrain Park area

07:42 AM CST on Tuesday, February 13, 2007

WWL-TV and Associated Press reports

An 85-year-old woman was killed and at least seven people were injured as a tornado touched down twice this morning first in Westwego and then jumped over the Mississippi River and hit in the Carrollton and Gentilly areas of New Orleans. The tornado was part of a heavy line of storms that blew through around 3 a.m.

Bill Haber / Associated Press

A tree and power line sit on top of a car in the Carrollton area of New Orleans after a tornado struck early Tuesday.

The woman who was killed lived in the Pontchartrain Park area, according to New Orleans Fire Department officials. The Gentilly area was especially hard hit.

Entergy spokesman Morgan Stewart says that approximately 17,000 customers are without power in the Carrollton area. In Westwego about 650 customers are out, mainly in the heavily-damaged area. Another 8,000 outages are reported in New Orleans East and Gentilly and sporadic outages of about 2,500 in Metairie and Kenner.

Colonel Jerry Sneed of the New Orleans Department of Emergency Preparedness said he has reports of 'fewer than 20 injuries' in Orleans, many of them who were treated and released.

Also Online

VIDEO: Carrollton residents afraid as storms slammed area

VIDEO: Westwego hotel destroyed

VIDEO: Homes destroyed, trees, power lines ripped down

On Carrollton Avenue Uptown, there was plenty of visible damage with businesses having signs down and some windows out. A huge hole was seen in the brick facade of Ronald McNair School on Carrollton.

Several homes near S. Claiborne and Carrollton had severe damage. At least one family had the roof of their FEMA trailer ripped off with a family inside. All were able to escape alive.

On the West Bank, nine people were reported injured, six of them who were staying at the Bon Soir motel when the roof was ripped off by the tornado. WWL-TV reporter Jonathan Betz said the motel looks as if a 'bomb went off' and that it is completely gutted.

A six-block area near the hotel was hit by the tornado and at least 15 homes were damaged.

The hotel's roof was torn off and is lying in the middle of the Westbank Expressway, causing traffic to be shut down in both directions on the West Bank Expressway.

Authorities say trailers were overturned in the area, and at least six homes collapsed. So far, there's no word on the condition of the residents.

Jefferson Parish authorities are sending teams through the area to check on residents.

In New Orleans, damage is widespread in the Carrollton area and many areas of New Orleans are without power this morning
Member Since: July 3, 2005 Posts: 427 Comments: 129439
121. Patrap
7:43 AM CST on February 13, 2007
Tornado damage in New Orleans this morning.Was BAd storm...lotsa power outages .Link
Member Since: July 3, 2005 Posts: 427 Comments: 129439
120. tofarout
12:50 PM GMT on February 13, 2007
http://www.canadafreepress.com/2007/global-warming020507.htm
Member Since: Posts: Comments:
119. tofarout
12:29 PM GMT on February 13, 2007
http://www.timesonline.co.uk/tol/news/uk/article1363818.ece
Member Since: Posts: Comments:
118. mrpuertorico
6:40 AM AST on February 13, 2007
THIS HAZARDOUS WEATHER OUTLOOK IS FOR PUERTO RICO.

.TODAY AND TONIGHT...DRY WEATHER OVER THE PAST SEVERAL WEEKS HAS
INCREASED THE CHANCE FOR FIRES ACROSS PARTS OF SOUTHERN PUERTO RICO.
OTHERWISE...NO HAZARDOUS WEATHER IS EXPECTED.

.DAYS TWO THROUGH SEVEN...NO HAZARDOUS WEATHER CONDITIONS ARE
EXPECTED AT THIS TIME.

hmm could a drought be on the way
Member Since: July 10, 2006 Posts: 1 Comments: 833
115. sporteguy03
3:36 AM GMT on February 13, 2007
Thanks Steve I was reading the discussion but there is alot of uncertainity does El Nino have any effect on this? I been hearing that could could makes these storms worse?
Member Since: Posts: Comments:
114. SteveDa1
10:32 PM EST on February 12, 2007
Or this:

Tuesday...Considerable cloudiness. Scattered afternoon showers and thunderstorms. Some thunderstorms May become strong. Highs in the mid 70s. East winds 5 to 10 mph shifting to the south in the afternoon. Chance of rain 50 percent.
Member Since: Posts: Comments:
113. SteveDa1
10:31 PM EST on February 12, 2007
From NWS:

Orlando, FL
TUESDAY
Scattered Afternoon T-Storms
Hi: 75įF
Pop: 50%

Member Since: Posts: Comments:
112. sporteguy03
3:24 AM GMT on February 13, 2007
Is there a Good Chance of Severe Weather near Orlando tomorrow? Where is the dry weather?
Member Since: Posts: Comments:
111. hurricane23
6:11 PM EST on February 12, 2007
Its all about the steering patterns that might be in place.La nina indeed will make conditions overall more favorable for tropical developement but whether or not the united states see's some activity this season will depend on alot of factors that will slowly reveal themselves over the next couple of months.Adrian
Member Since: May 14, 2006 Posts: 8 Comments: 13841
110. CaneAddict17
11:12 PM GMT on February 12, 2007
Look at what the GFS has in store for Florida on the 24th... 12z, and 18z
Member Since: Posts: Comments:
109. Tazmanian
2:43 PM PST on February 12, 2007
we no that
Member Since: Posts: Comments:
108. CaneAddict17
10:38 PM GMT on February 12, 2007
El Nino is almost finished
El Nino
Member Since: Posts: Comments:
107. HadesGodWyvern (Mod)
10:01 PM GMT on February 12, 2007
Ice Storm Warning - Virginia
Member Since: Posts: Comments:
106. Jorick23
9:24 PM GMT on February 12, 2007
All you people talkin' about a little rain, sheesh! I've got 18 inches of snow coming my way tomorrow night!

Now where's the number of that Florida travel agency?....
Member Since: Posts: Comments:
105. hurricane23
4:16 PM EST on February 12, 2007
Updated discussion for Miami....Rainy weather for the next couple of hours before things get better.


...A FEW STRONG STORMS POSSIBLE MAINLY EXTREME SE COAST AND
ADJACENT WATERS TONIGHT...
...POTENTIAL COLD WEATHER EVENT LATE THIS WEEK...
Member Since: May 14, 2006 Posts: 8 Comments: 13841
103. hurricane23
4:01 PM EST on February 12, 2007
On radar you can see things will begin to clear up rain wise in the next couple of hours.Off and showers are still possible later on tonight across southeast florida.
Member Since: May 14, 2006 Posts: 8 Comments: 13841

Viewing: 153 - 103

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

Top of Page

About

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

Local Weather

Overcast
32 °F
Overcast