Averaging together antarctic and arctic sea ice hides an important truth
Since my last post designating arctic sea ice loss as the top climate story of 2008, I've heard a lot comments like this one: "Jeff, you just can't seem to understand the that man-made global warming is a fable and complete hoax. In all that blathering about the falsified IPCC reports and the study of the arctic ice sheet, you somehow neglected to mention that the ice recovered not only what it lost last year, but is now larger than the previous known record measured in 1978".
Well, I can understand this point of view, given complexity of the climate change issue, and the large amount of conflicting information one sees in the media. Let's look at the facts about global sea ice. You can look at the data yourself at the excellent University of Illinois Cryosphere Today web site. Reliable sea ice records go back to 1979, when satellite measurements began. Antarctic sea ice reached its greatest extent on record during the winter of 2007. Summertime ice coverage also increased in 2007-2008 compared to 2006 levels (Figure 1). However, as one can see from Figure 1, there is high variability in antarctic sea ice from winter to summer, and antarctic sea ice can best be described as having stayed constant since 1979 (as stated in the 2007 report of the Intergovernmental Panel on Climate Change (IPCC). The IPCC did find that there had been a significant decline in arctic sea ice, in all seasons, between 1979-2006. Despite this decline, there have been three periods during the past two years when the sum of the arctic and antarctic sea ice was the same or even higher than it was at the start of the satellite era (1979). An article published January 1 on Daily Tech noted that "global sea ice levels now equal those seen 29 years ago". This was pretty close to the truth on December 31, 2008, despite the fact that arctic ice was 1 million km^2 below 1979 levels, since antarctic ice was 0.5 million km^2 above 1979 levels. Although arctic sea ice extent has steadily declined since 1979, especially in summer, this decline is not as great during the winter months. One can find periods in winter when summing together antarctic and arctic sea ice area makes it appear that arctic sea ice loss is no big deal.
However, this is the wrong way to look at the issue. We don't care much about global sea ice in winter. We care about arctic sea ice in the summer. Sharp declines in summertime arctic ice are likely to cause significant and damaging alterations to Earth's climate. Cleverly quoting irrelevant facts about global wintertime sea ice data to hide the summertime loss of arctic sea ice is a tremendous disservice. It's like hiding the potential impact of a major hurricane in a one-week forecast by saying, "the average peak wind speed for the next seven days will be 17 mph", and neglecting to mention that the wind will be calm six of those days, but 120 mph on the other day. The loss of arctic sea ice the past two summers, is, in my view, the most important human-caused climate change event yet--even more significant and dangerous than the opening of the antarctic ozone hole in the 1980s. It's great that we're not seeing loss of sea ice in Antarctica. But, both the Antarctic and the Arctic can be thought of as important internal organs in our living Earth. The fact that the Antarctic has not undergone significant warming and sea ice loss in no way diminishes the urgency with which climate scientists view the diseased state of our Arctic. Fully 88 presentations on arctic sea ice were made last month at the world's largest scientific climate change conference, the American Geophysical Union (AGU) meeting in San Francisco. None of these scientists averaged together the arctic and antarctic sea ice together to show that the overall state of Earth's cryosphere was a healthy one. There was widespread concern for the health of the Arctic among all the scientists I spoke with, and none of the speakers at the talks I attended expressed the idea that the recent melting of arctic sea ice was predominantly natural, with human-caused climate change an insignificant factor. One view (Stroeve et al., 2007) is that human-emitted greenhouse gases are responsible for 47-57% of the arctic sea ice loss since 1979. Heat-absorbing black soot from fires and pollution settling on the white ice is thought to also be a significant contributor.
Figure 1. Antarctic sea ice area as observed via satellite since 1978. The maximum area in winter has ranged between 14-16 million square kilometers, about the same amount of ocean that the Arctic ice covers in winter. However, the antarctic sea ice almost entirely melts away in summer, something the Arctic sea ice does not do (yet). Antarctica is a huge continent that rises thousands of feet above the ocean. It holds about 90% of the world's fresh water, locked up in its massive ice cap. The presence of such a titanic block of ice at the bottom of the world completely dominates the weather and climate of the region, and the year-to-year fluctuations of sea ice don't have a lot of impact on temperatures there. Image credit: University of Illinois Cryosphere Today.
What is the current state of Antarctic climate?
At the December 2008 AGU meeting, scientists gave Antarctica a mixed bill of health. Isabella Velicogna of UC Irvine reported that satellite gravitational variation measurements of Antarctica's ice cap showed significant loss of ice between 2002-2008, but that the large natural variations in melting with the seasons made it difficult to be confident of the results. A somewhat different result was reported by J. Zwally of NASA. Using data from a higher-resolution satellite-borne laser altimeter, he found that there was no major loss of Antarctica's ice sheet between 2003-2007. Regardless of which data set is correct, Antarctica is in better shape than the Arctic because Antarctica has stayed relatively cool in recent decades (Figure 2). For example, the surface temperature at the South Pole cooled 0.05° C between 1980 and 1999 (Kwok and Comiso, 2002). The majority of Antarctica has shown no statistically significant warming over the past 50 years (Turner et al., 2005), and cooling has just been dominant between 1982-2004. In the period 2004-2007, much of the Antarctic warmed (Figure 3), but it is too early to say if this is the beginning of a warming trend. Check out the January 22 issue of Nature when new results about whether or not Antarctica is warming will be published.
Figure 2. Antarctic surface temperatures as observed via AHVRR satellite measurements between 1982 and 2004. Much of Antarctica cooled during this period. Image credit: IPCC The Physical Science Basis, Figure 3.32.
Figure 3. Antarctic surface temperatures as observed via AHVRR satellite measurements between 1981 and 2007. Note that the cooling trend observed from 1982-2004 reversed, thanks to warming from 2004-2007. Image credit: NASA
Why did Antarctica cool between 1982 and 2004 if there was global warming going on?
The weather of the Antarctic is dominated by a strong band of westerly winds that blow around the pole. This circumpolar vortex extends from the surface to the stratosphere, and can attain very high wind speeds, thanks to the absence of large land masses to slow it down. This vortex tends to isolate Antarctica from the rest of the globe, keeping global warming from influencing Antarctica's weather, and allowing the surface to cool. The Antarctic Peninsula, which sticks out from Antarctica towards South America, frequently lies outside the vortex. This has allowed the peninsula to warm significantly, compared to the rest of Antarctica (Figures 2 and 3). The antarctic circumpolar vortex has strengthened in the past 25-30 years, forming an even stronger barrier than usual. Tree ring records (Jones and Widman, 2004) suggest that the circumpolar vortex has shown similar strengthening in the past, so the current cooling trend in Antarctica may be natural.
Another possibility, favored by climate modelers, is that the strengthening of the circumpolar vortex and recent cooling in Antarctica are primarily due to a combination of the recent increase in greenhouse gases and the opening of the Antarctic ozone hole. The ozone hole opened up at about the same time as the recent cooling began. Ozone absorbs UV radiation which heats the atmosphere around it, so the absence of ozone has led to cooling in the stratosphere over Antarctica. This cooling has been about 10° C in October-November since 1985 (Thompson and Solomon, 2002). This has acted to intensify the circumpolar vortex, leading to surface cooling. If the climate modelers are right, the circumpolar vortex will weaken as the ozone hole diminishes in coming decades. This will allow the Antarctic to begin warming with the rest of the globe, in a decade or two.
References and resources
Intergovernmental Panel on Climate Change (IPCC), 2007, The Physical Science Basis.
Jones, J.M., and M. Widman, "Atmospheric science: Early peak in Antarctic oscillation index," Nature 432, 290-291 (18 November 2004) | doi:10.1038/432290b; Published online 17 November 2004.
Kwok, R., and J.C. Comiso, "Spatial patterns of variability in Antarctic surface temperature: Connections to the Southern Hemisphere Annular Mode and the Southern Oscillation", GEOPHYSICAL RESEARCH LETTERS, VOL. 29, NO. 14, 10.1029/2002GL015415, 2002.
Thompson, D.W.J., and S. Solomon, "Interpretation of Recent Southern Hemisphere Climate Change", Science 3 May 2002: Vol. 296. no. 5569, pp. 895 - 899 DOI: 10.1126/science.1069270.
Stroeve, J., M.M. Holland, W. Meier, T. Scambos, and M. Serreze, Arctic sea ice decline:Faster than forecast", GRL 34 L09501, doi:1029/2007GL029703, 2007.
Turner, J. et al., 2005, "Antarctic climate change during the last 50 years", International Journal of Climatology, Volume 25, Issue 3, pp 279-294.
Arctic sea ice
"Antarctic cooling, global warming?" RealClimate.org post, 3 December 2004.
Volunteers needed for disaster relief fund-raising
The portlight.org disaster relief charity is in the process of wrapping up its Hurricane Ike relief efforts, and is looking ahead to the future. According the new wunderground featured blog, Portlight Disaster Relief, "Our goals are to expand our network of supporters, continue to create a sense of ownership and community and create a financial reserve. Achieving these goals is critical to us being able to serve future hurricane victims in a strategic, pro-active and efficient manner." To this end, Portlight is sponsoring a fund-raising effort this March and April in 40 cities--a Spring Relief Walk. Volunteers in twenty cities have already committed to the effort, and more volunteers are needed! Check out the Portlight Disaster Relief blog for more information.
Coming Monday: Inauguration Weather. Wednesday: is the globe cooling? A report on temperatures for 2008, merely the 9th warmest year on record.
Jeff Masters
Reader Comments
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Things are gunna get a li'l blustery here.
First system will work its way into the NW of Britain over the weekend. Winds will reach minimum hurricane strength (80mph) at maximum. Pressure is predicted to be in the low 950mbs. A Storm/Severe Gale Watch has been issued by the Met Office for NW Scotland at this time.
Latest models suggest another strong low will move in during next week, bringing yet more gale conditions and mucho rain. This is perhaps the one that has been hinted at for the last week.
Boundless joy.
Antarctic winter trends are small,
comparisons for summer are confounded by generally poor
model performance. Citation: Stroeve, J., M. M. Holland,
W. Meier, T. Scambos, and M. Serreze (2007), Arctic sea ice
decline: Faster than forecast, Geophys. Res. Lett., 34, L09501,
doi:10.1029/2007GL029703.
1. Introduction
[2] Climate models are in near universal agreement that
Arctic sea ice extent will decline through the 21st century in
response to atmospheric greenhouse gas (GHG) loading...
Now I know one was talking about antarctic and the other arctic, but still - state the models are poor in one sentence, then raise the alarm that the models are saying havoc is on the way.
Stick to the tropics please
TampaSpins Weather Blog Link
WELL SAID DOC!
And precisely what Limbaugh and all the other denialists do all the time.
Good morning everyone,
Don't know about snow - it is pretty dry here. (DRY CONDITIONS THIS AFTERNOON WILL INCREASE THE FIRE DANGER) per NWS. I worry more about that danger, seeing as people (especially the homeless) will be seeking ways to stay warm.
Would be interesting (fun for the kids) if it does snow. Warning to all - if it does snow - watch out for us. We do not know how to drive in the snow, but it is soooo much fun. You may want to stay off the roads, while the fool hardy have their fun. (When it comes to navigating flooded streets - I will put the skills of Charlestonians up against anyone.)
Not sure how cold it was early this morning. It is 49.5°F on the peninsula right now. (66°F in my room now). The real blast has yet to hit - but is certainly on the way. High pressure is increasing - quite evident on the Folly Beach Buoy off the coast.
What caught my attention, TampaSpin, was your comments on a TS in January!! Imagine if we were to have both a TS and Snow -- Yikes!
I have been wondering lately, why the melt is not as severe in the South, and thought that the Industrialised North could have an impact on the North Polar ice that was not being experienced in the South.
Your point on the continous "wind shield" around the South Pole is one that I had not considered.
Good point....
latest water vapour showing aoi off east yuc
That moisture is what im talking about combinded with the low temps tonite will make things very interesting in parts of Florida...white stuff could be very possible!
If I travel to a hurricane this year, and if the hurricane hits during daylight hours, and it's relatively safe enough to do so...I intend to get caught up in a storm surge and be swept away by it.
Whatever you're smokin, I want some.
another aoi is near 16n/52w there is a ccc present and movement is west north west with the feature
Keeper i have this feature on my blog as well..i think it has a chance to develop as well as i layed out the reasoning in my blog....could become the first named storm possibly......
now that would be wild
No...I actually don't. I could easily pass a urine test.
It is not going to snow in Florida.
Dude I am only 6 yrs older than you, just need to make certain you have really thought this out and not running on Machismo alone. Also nasty chemical spills, fire ants, snakes, gators, drowning people, cats & dogs ect. all may be viewing you as a life raft.
Ike did you get up on the wrong side of bed this morning......LOL.......calm down....LOL
LOL....good luck.
Calm down? I'm basing my opinion on reading every discussion in the SE USA on here.
Actually I didn't sleep in a bed last night. I slept on my nicely cushioned couch.
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MELBOURNE FL
950 AM EST THU JAN 15 2009
.DISCUSSION...
CURRENT...A REINFORCING COLD FRONT WITH ARCTIC AIR CONTINUES TO DIVE
TOWARD THE DEEP SOUTH THIS MORNING. A LARGE AREA OF HIGH PRESSURE
OVER THE CENTRAL PLAINS AND UPPER MIDWEST WILL CONTINUE TO EXPAND
SOUTHEASTWARD THROUGH THE DAY. UPDATED ZONES A BIT EARLIER TO CLEAN
UP FIRST PERIOD WORDING. REST OF PACKAGE IN GOOD SHAPE.
TODAY/TONIGHT...(PREVIOUS)...NW FLOW STILL FCST TO INCREASE LATE
TODAY/TONIGHT AND VEER MORE TO NRLY BEHIND APPROACHING FRONT. MAJOR
CHG IN FCST IS THAT MODELS ARE QUITE GUNG-HO ON INCREASING UPR
RH/DIVG THIS AFTN THRU TONIGHT. BY 18Z...THE H40-H20 LYR IS PROGGED
TO BE NEARLY SATURATED AND REMAIN SO THRU SUNRISE FRI. H30-H20 DIVG
WILL INCREASE AND BECOME FAIRLY STOUT OVHD FROM 00Z-12Z. THIS
PORTENDS THICKENING HIGH CLOUDS BY THIS AFTN...AND REMAINING OVHD
THROUGH TONIGHT. AND WHILE THIS WILL FILTER SUNSHINE AND LOWER MAXES
BY A COUPLE DEGREES UNDER WHAT THEY WOULD OTHERWISE BE...THICKEST
CLOUDS ARE PROGGED BY TONIGHT...WHICH SHOULD KEEP MINS SEVERAL
DEGREES ABOVE WHAT WE HAD PREVIOUSLY FCST. SO WHILE TEMPS WILL BE
COOL TO COLD TODAY/TONIGHT ...THIS MAKES A WDSPRD FREEZE ACROSS THE
FAR NORTH SEEM MUCH LESS LKLY THAN IT DID EARLIER THIS WEEK. MIN
TEMP GUIDANCE HAS COME UP ABOUT A FULL CAT ACROSS THE AREA...AND THE
GRIDS/ZFP WILL FOLLOW SUIT. AM HESITANT TO PULL THE FREEZE WATCH
JUST YET...BUT BASED ON CURRENT SAT IMAGERY...WILL NOT BE SURPRISED
TO SEE IT PULLED LATER THIS AFTN.
WARMER MINS ALSO LKLY TO LIMIT SWD PUSH OF SUBFREEZING WCI`S. NRLY
WINDS ARE STILL PROGGED AT AROUND 10 MPH MOST OF TONIGHT...WHICH
RESULTS IN LOWEST WCI`S IN THE U20S (AS OPPOSED TO THE PREV TWO NGTS
FCST OF 20F/LWR 20S) ACROSS THE FAR NORTH..AND THE 32F WCI LINE NEAR
OR A LITTLE SOUTH OF I-4 BY 12Z. AM OBLIGED TO WAIT ON 12Z GUIDANCE
FOR BETTER DELINEATION OF COLDEST WIND CHILLS BEFORE ISSUING ANY NPW/
WIND CHILL ADV. WILL STILL BE MAIN FOCUS IN THE HWO/G-HWO HOWEVER.
So what about those long-lived CO2 molecules?
In all seasons are they not reflecting longwave radiation back to the surface in Antarctica?
And doesn't your average CO2 molecule have a lifespan in the atmosphere long enough to be thoroughly mixed in (so the CO2 concentration would also have risen in Antarctica just as it has in the last 50 years at Muana Loa)?
So vortex or no vortex, either case, why would Antarctica overcome the effect of increasing CO2 re-radiating heat back to the surface...including after O3 holes started up? (Note the hole itself usually only lasts a few weeks after the SH winter and couldn't possibly have an effect in SH summer/fall).
I am of the opinion that black soot has far more to do with our NH melting than it is being given consideration for. I cannot remember whom but some Norwegian in the 1700s made a note of black soot in the Arctic and I completely expect that has gotten far worse over the last 50 years, especially that coming from Asia.
Now, I am no fan of the CO2 AGW thoery. I can accept an possible anthropogenic effect from soot and the simple measures that would reduce black carbon emissions if we can be shown just what the effect is and how much soot there is in the Arctic. But an effective method of measuring black soot on ice needs to be developed. This mechanism has rather clear potential to be a major player in ice melt, which you have so well put, has an effect on the rest of the planet. Is there enough soot to have a real effect? I don't think we collectively know.
Addendum: Obviously there would be no effect in the winter at either pole. Soot as a warming agent on/in the ice would only be effective in the presence of sunlight.
This came from an email just a few minutes ago......so some forecasters with status is seening the same......
This morning sitting at the bus stop my 12 year old was telling me he heard on the news this morning there was a slight chance for snow across some parts. I told him no way!
Guess he heard right. LOL
Same here in Defuniak Springs,FL. I'm on lake-front property with another lake across the street. It's almost always about 5 degrees warmer then forecast.
My forecast for tonight is for a low from 22 to 26. That usually means upper 20's where I live.
I haven't read it anywhere in any discussion. If it does happen, I'll cheerfully eat crow on here tomorrow. Maybe you'll be right.
That is brilliant!!! This guy oughta teach....
That sounds like New Orleans and it's relative northshore across the lake. Our lows on the northshore are almost always 8 - 12 degrees F colder than any of the NOLA weather stations.
Ask a Question
Do Background Research
Construct a Hypothesis
Test Your Hypothesis by Doing an Experiment
Analyze Your Data and Draw a Conclusion
Communicate Your Results
"I asked for an order of GW, well-done, with a side of home fries yesterday. Since I didn't get any, I guess that means that GW doesn't exist."
"Hey, is this thing on?"
Mysterious columns of coloured light
I agree...good analogy.
That could be taken the other way, too, though, in the realm of surface temperature measurements. The "global mean temperature" business does not tell you that a couple of hundred of our coldest observation stations suddenly closed in Siberia in the 90s, right around our "warmest years".
So the mean temperature trend neglects the fact that the coldest stations on the planet that stopped reporting at the same time warming supposedly accelerated.
Statistics can show you anything you want it to.
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