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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53. Tazmanian
11:34 AM PST on February 12, 2007
ok sky i see now
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51. Tazmanian
11:33 AM PST on February 12, 2007
weatherboykris what are the ENSO numbers saying today
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50. weatherboykris
7:33 PM GMT on February 12, 2007
Some 50kt winds offshore.Bad boating.Wonder if there's rain contamination and that's why they're so high?
Member Since: December 9, 2006 Posts: 125 Comments: 11346
49. Skyepony (Mod)
7:27 PM GMT on February 12, 2007
I don't know Taz never got into figuring snow though alot will have to do with it's track, been trending toward land lately.

Here's the quickscat of the gulf.

Interesting how some of the model now have switched to the front meeting the surface trough right before, or as it crosses Fl instead of after. That won't help for avoiding severe weather.
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48. weatherboykris
7:12 PM GMT on February 12, 2007
Yeah,you can see the overshooting tops of the storms.Nice.You see the latest ENSO numbers?Link
Member Since: December 9, 2006 Posts: 125 Comments: 11346
47. Tazmanian
11:16 AM PST on February 12, 2007
wow sky could NY city see 2 to 3 ft for this storm
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45. hurricane23
2:12 PM EST on February 12, 2007
Weatherboychris no tropical developemnt is expected but if a weak low were to try to form it will only add to the rain amounts across south florida in the coming hours as this entire areas drifts north.

Part of the NWS discussion form earlier this morning...

THIS IS WHERE YOU GO ON A LIMB DUE TO THAT DATA HOLE THAT IS THE
GULF OF MEXICO. THERE COULD BE...ARGUABLY A WEAK SFC LOW TRYING TO
DEVELOP SOMEWHERE AROUND THE YUCATAN PENINSULA BUT IT IS HARD TO
FIND EVEN VIA HAND ANALYSIS. THIS IS PERHAPS WHAT GFS IS LATCHING ON
TO WHICH IT DEVELOPS RATHER AGGRESSIVELY AS THE DAY PROGRESSES IN
RESPONSE TO UPR LVL S/W FORCING. IF THIS HAPPENS, THEN THERE IS NO
DOUBT SFC TROUGH TO OUR SOUTH SHOULD LIFT NORTH AS THE LOW AND UPR
LVL S/W APPROACHES WEST CENTRAL AND SW FLORIDA TONIGHT INCREASING
SEVERE WEATHER THREAT ACROSS THE AREA.
Member Since: May 14, 2006 Posts: 8 Comments: 13621
44. Skyepony (Mod)
7:13 PM GMT on February 12, 2007
& Taz it so looks more like it may roll up the coast instead of stay off shoar, NY may be in for alot more.
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43. Skyepony (Mod)
7:08 PM GMT on February 12, 2007
Weak surface low isn't out of the question, for the gulf (though it looked more likely lastnight). Check the clouds down there on the RGB They're mostly in the lower levels. So shear wouldn't play as big apart unless it tried to strengthin, make higher clouds.
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42. Skyepony (Mod)
7:05 PM GMT on February 12, 2007
That TX storm caught my eye on the RGB Got some hail kickin.
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41. weatherboykris
7:06 PM GMT on February 12, 2007
that won't develop.
Member Since: December 9, 2006 Posts: 125 Comments: 11346
40. weatherboykris
7:05 PM GMT on February 12, 2007
nah.Shear's too strong.That'd be cool though.
Member Since: December 9, 2006 Posts: 125 Comments: 11346
38. Tazmanian
11:03 AM PST on February 12, 2007

FINAL STORM TOTALS has of today

PARISH NY 121"


REDFIELD 141"


this most be the most snow they had evere seen in one storm and you no what more is on the way where are they all going to put it
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37. hurricane23
1:58 PM EST on February 12, 2007
cyclonebuster i just spoke about that on randrewls blog...Indeed maybe hints of a weak surface low trying to develope down there.Should move north a bring heavy towards dade and broward counties.
Member Since: May 14, 2006 Posts: 8 Comments: 13621
35. hurricane23
1:25 PM EST on February 12, 2007
Good afternoon,

Ive recieved a couple of phone calls from some friends down in the keys and they have said its been pouring really hard for hours down there with gusty winds also in the mix.Hopefully things will begin to slow down as the afternoon approaches.

View of keywest radar....


Member Since: May 14, 2006 Posts: 8 Comments: 13621
34. HadesGodWyvern (Mod)
6:19 PM GMT on February 12, 2007


an active southwestern Indian Ocean.
Member Since: May 24, 2006 Posts: 50 Comments: 44446
31. mrpuertorico
1:10 PM AST on February 12, 2007
this rule also applies to all puerto ricans who want to leave the island.
Member Since: July 10, 2006 Posts: 0 Comments: 833
30. mrpuertorico
1:00 PM AST on February 12, 2007
Posted By: Dodabear at 11:14 AM AST on February 12, 2007.

Don't need passports to go to Puerto Rico

acctually now as of december 2006 all us citizens traveling to puerto rico will need passports to travel to and from the island drivers license will not get u in!
Member Since: July 10, 2006 Posts: 0 Comments: 833
28. pottery
12:00 PM AST on February 12, 2007
.in any event, the point is that bad weather in the Eastern US is good for the economy of Puerto Rico.........
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27. pottery
11:58 AM AST on February 12, 2007
...or rather, concentrates the tourist flow to PR and the USVI. Its all for " SECURITY " you see..........
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26. pottery
11:53 AM AST on February 12, 2007
Re: no pasports for PR. I know, and the rules have changed very recently, and you have to have one to visit any other Carib. islands. Eliminates a lot of tourists !!!!!!!!!
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25. 882MB
3:54 PM GMT on February 12, 2007
Hey everybody, Very active morning here across SOUTH FLORIDA. KEY WEST RADAR REALLY SHOWING HEAVY THUNDERSTORMS WITH ROTATION MOVING NORTH!I HAVE A FEELING WE MIGHT HAVE A LITTLE SEVERE WEATHER HERE IN MIAMI LATER ON THIS AFTERNOON!
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24. Dodabear
10:04 AM EST on February 12, 2007
Don't need passports to go to Puerto Rico
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23. pottery
10:55 AM AST on February 12, 2007
V26R, we dont expect any rain in the Caribbean until June. Thats when the itcz gets to me, anyway. Further north, at Puerto Rico, Antigua etc. they have to wait on the first trop. wave off Africa to give them any real relief.
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22. pottery
10:45 AM AST on February 12, 2007
MRP, the weather in the states is going to have an effect on Puerto Rico. i.e. the tourists are going to come, without their passports. LOL.
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21. V26R
2:43 PM GMT on February 12, 2007
Got bud over in Antigua right now and when I last talked with him, he said that he was getting dry condx just like you guys in PR
Hope you get some rain down there soon!
Member Since: July 20, 2006 Posts: 0 Comments: 1762
20. mrpuertorico
2:18 PM GMT on February 12, 2007
Yeah v26r i was thinking the same thing. I wounder if the weather in the states will have any impact on us in the caribbean.
Member Since: July 10, 2006 Posts: 0 Comments: 833
19. V26R
1:54 PM GMT on February 12, 2007
Guess the Low Pressure system thats supposed to give the Northeast a Snow is starting to wind up
Member Since: July 20, 2006 Posts: 0 Comments: 1762
18. Randrewl
1:54 PM GMT on February 12, 2007
Another one!



BULLETIN - EAS ACTIVATION REQUESTED TORNADO WARNING NATIONAL WEATHER SERVICE KEY WEST FL 849 AM EST MON FEB 12 2007 THE NATIONAL WEATHER SERVICE IN KEY WEST HAS ISSUED A * TORNADO WARNING FOR... MIDDLE KEYS IN MONROE COUNTY IN FLORIDA UPPER KEYS IN MONROE COUNTY IN FLORIDA * UNTIL 905 AM EST * AT 847 AM EST...DOPPLER RADAR INDICATED A ROTATING THUNDERSTORM NEAR CRAIG KEY...MOVING NORTHEAST NEAR 10 MPH. THIS THUNDERSTORM IS CAPABLE OF PRODUCING A TORNADO. * OTHER LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO LOWER MATECUMBE KEY WATERSPOUTS THAT MOVE ONSHORE ARE DANGEROUS AND CAN BE DEADLY. IF THREATENING WEATHER APPROACHES...SEE SHELTER IMMEDIATELY! DO NOT USE YOUR CAR TO TRY TO OUTRUN A TORNADO. CARS ARE EASILY TOSSED AROUND BY TORNADO WINDS. IF YOU ARE CAUGHT IN THE PATH OF A TORNADO...LEAVE THE CAR AND GO TO A STRONG BUILDING. IF NO SAFE STRUCTURE IS NEARBY...SEEK SHELTER IN A DITCH OR LOW SPOT AND COVER YOUR HEAD. PLEASE REPORT SEVERE WEATHER TO THE NATIONAL WEATHER SERVICE KEY WEST AT 3 0 5...2 9 5...1 3 1 6...EXTENSION 3. LAT...LON 2480 8090 2475 8076 2492 8068 2498 8081
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17. Randrewl
1:26 PM GMT on February 12, 2007
BULLETIN - EAS ACTIVATION REQUESTED TORNADO WARNING NATIONAL WEATHER SERVICE KEY WEST FL 820 AM EST MON FEB 12 2007 THE NATIONAL WEATHER SERVICE IN KEY WEST HAS ISSUED A * TORNADO WARNING FOR... MIDDLE KEYS IN MONROE COUNTY IN FLORIDA UPPER KEYS IN MONROE COUNTY IN FLORIDA * UNTIL 850 AM EST * AT 816 AM EST...OUR RADAR DETECTED A WATERSPOUT JUST SOUTH OF LONG KEY...DRIFTING NORTH. * LOCATIONS IN THE PATH INCLUDE MILE MARKER 66 AND 67...THE EDGEWATER LODGE...LONG KEY STATE PARK AND THE LONG KEY VIADUCT. WATERSPOUTS THAT MOVE ONSHORE ARE DANGEROUS AND CAN BE DEADLY. IF THREATENING WEATHER APPROACHES...SEEK SHELTER IMMEDIATELY! LAT...LON 2467 8079 2476 8066 2497 8083 2486 8093
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16. Randrewl
1:25 PM GMT on February 12, 2007
BULLETIN - EAS ACTIVATION REQUESTED TORNADO WARNING NATIONAL WEATHER SERVICE KEY WEST FL 820 AM EST MON FEB 12 2007 THE NATIONAL WEATHER SERVICE IN KEY WEST HAS ISSUED A * TORNADO WARNING FOR... MIDDLE KEYS IN MONROE COUNTY IN FLORIDA UPPER KEYS IN MONROE COUNTY IN FLORIDA * UNTIL 850 AM EST * AT 816 AM EST...OUR RADAR DETECTED A WATERSPOUT JUST SOUTH OF LONG KEY...DRIFTING NORTH. * LOCATIONS IN THE PATH INCLUDE MILE MARKER 66 AND 67...THE EDGEWATER LODGE...LONG KEY STATE PARK AND THE LONG KEY VIADUCT. WATERSPOUTS THAT MOVE ONSHORE ARE DANGEROUS AND CAN BE DEADLY. IF THREATENING WEATHER APPROACHES...SEEK SHELTER IMMEDIATELY! LAT...LON 2467 8079 2476 8066 2497 8083 2486 8093 --------------------------------------------------------------------------------
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14. biff4ugo
7:45 AM EST on February 12, 2007
Yet more info on anthropogenic forcing. I agree it is a contribution to climate change but what is important is can we DO anything about it. What I am reading is that even if we stop or level gg production the climate will continue to change. The next critical question is how do we COPE with the changes and figure out what they are. Should we start farms in Greenland so we don't starve or what? Roll white permeable plastic membrane over the arctic or just start farming salmon there? We need bright people like the Dr. here to work on those questions too.
It seems important to stop making climate change worse with greenhouse gas production but it is even more important not to make it worse by trying to "FIX" it without proper forethought.
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13. pottery
8:56 AM AST on February 12, 2007
We had a drizzle here early this morning, and there is a little cloud about. very welcomed.......
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12. mrpuertorico
7:45 AM AST on February 12, 2007
well another week of dry air on tap for us in the caribbean. Getting very dry here...i miss the rain.
Member Since: July 10, 2006 Posts: 0 Comments: 833
11. phillyfan909
5:11 AM GMT on February 12, 2007
Dr Masters, thanks for the info as always. I appreciate the cautious tone, and I appreciate your avoiding any sweeping statements, while still building a case that even the skeptics can't dismiss.
This reminds me of the cigarette controversy a few decades ago. The tobacco industry always denied a link between smoking and cancer and heart disease etc, and insisted there was never a causal link, that it was always coincidence, in spite of all the studies that showed otherwise. Meanwhile millions were sickened and died over the years while the debate went on. This looks like the same deal, except by the time everyone reaches a consensus this time, Florida will be gone! ;-)
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10. weatherboykris
4:52 AM GMT on February 12, 2007
Thanks Dr. Masters
Member Since: December 9, 2006 Posts: 125 Comments: 11346
9. Tazmanian
8:50 PM PST on February 11, 2007
LOL dr m you said that your next blog would be monday i did not no today was monday lol but thanks for the update
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8. barrygilmour
12:59 PM WST on February 12, 2007
Jeff,
Would that "ice-albedo feedback" effect contribute to our Antarctic accelerated ice-melts also?
Barry
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6. pottery
10:39 PM AST on February 11, 2007
.....good, not goog.
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5. pottery
10:37 PM AST on February 11, 2007
Thank you, Dr. M. This is goog . Looking forward to more.
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3. Levi32
5:17 PM AKST on February 11, 2007
Thanks Dr. Masters. Good discussion.
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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.