Arctic Death Spiral: How It Favors Extreme, Prolonged Weather Events ‘Such As Drought, Flooding, Cold Spells And Heat Waves’

Posted on  

"Arctic Death Spiral: How It Favors Extreme, Prolonged Weather Events ‘Such As Drought, Flooding, Cold Spells And Heat Waves’"

We are headed for record lows in Arctic sea ice area and volume, as I discussed Monday.

The death spiral will start to make headlines in this country when we beat the record low sea ice extent set in 2007 as monitored by our National Snow and Ice Data Center. We are getting close, as the latest data make clear (see figure).

But the death spiral of Arctic ice deserves attention beyond its obvious indication of a warming planet. There is increasing scientific analysis suggesting that the loss of ice in the distant Arctic is helping drive the off-the-charts extreme weather we have been seeing right here in this country in recent years (see “Has Global Warming Caused A Quantum Jump In Extreme Weather?“)

In particular, a 2012 Geophysical Research Letters study, “Evidence linking Arctic amplification to extreme weather in mid-latitudes,” finds that the loss of Arctic ice favors “extreme weather events that result from prolonged conditions, such as drought, flooding, cold spells, and heat waves.”

One of the authors, Jennifer Francis of Rutgers University, explains her work in this video (longer video here):

This is likely to be the story of the decade, especially since we are are on track for large declines in summer Arctic sea ice by 2020 and since the extreme weather is already helping to drive food prices to record levels (see “Climate Story of the Year: Warming-Driven Drought and Extreme Weather Emerge as Key Threat to Global Food Security“)

These videos are a bit on the technical side, so I’m going to reprint excerpts of two more general discussions. Andrew Freedman, senior science writer for Climate Central, had a good post in April, “Arctic Warming is Altering Weather Patterns, Study Shows.” He explains:

The study shows that by changing the temperature balance between the Arctic and mid-latitudes, rapid Arctic warming is altering the course of the jet stream, which steers weather systems from west to east around the hemisphere. The Arctic has been warming about twice as fast as the rest of the Northern Hemisphere, due to a combination of human emissions of greenhouse gases and unique feedbacks built into the Arctic climate system.

The jet stream, the study says, is becoming “wavier,” with steeper troughs and higher ridges. Weather systems are progressing more slowly, raising the chances for long-duration extreme events, like droughts, floods, and heat waves.

“[The] tendency for weather to hang around longer is going to favor extreme weather conditions that are related to persistent weather patterns,” said Francis, the study’s lead author.

One does not have to look hard to find an example of an extreme event that resulted from a huge, slow-moving swing in the jet stream. It was a stuck or “blocking weather pattern” – with a massive dome of high pressure parked across the eastern U.S. for more than a week – that led to the remarkable March heat wave that sent temperatures in the Midwest and Northeast soaring into the 80s. In some locations, temperatures spiked to more than 40 degrees above average for that time of year.

The strong area of high pressure shunted the jet stream far north into Canada. At one point during the heat wave, a jetliner flying at 30,000 feet could’ve hitched a ride on the jet stream from Texas straight north to Hudson Bay, Canada. In the U.S., more than 14,000 warm-weather records (record-warm daytime highs and record-warm overnight lows) were set or tied during the month of March, compared to about 700 cold records.

Dr. Jeff Masters, Weather Underground director of meteorology and former hurricane hunter, also had a good explanation. Masters noted earlier this year that:

The climate has shifted to a new state capable of delivering rare & unprecedented weather events.”

Here is his longer discussion of Francis’s work:


Figure 1. Arctic sea ice in September 2007 reached its lowest extent on record, approximately 40% lower than when satellite records began in 1979. Sea ice loss in 2011 was virtually tied with the ice loss in 2007, despite weather conditions that were not as unusual in the Arctic. Image credit: University of Illinois Cryosphere Today.

Arctic sea ice loss can slow down jet stream winds

Dr. Francis looked at surface and upper level data from 1948 – 2010, and discovered that the extra heat in the Arctic in fall and winter over the past decade had caused the Arctic atmosphere between the surface and 500 mb (about 18,000 feet or 5,600 meters) to expand. As a result, the difference in temperature between the Arctic (60 – 80°N) and the mid-latitudes (30 – 50°N) fell significantly. It is this difference in temperature that drives the powerful jet stream winds that control much of our weather.

The speed of fall and winter west-to-east upper-level winds at 500 mb circling the North Pole decreased by 20% over the past decade, compared to the period 1948 – 2000, in response to the extra warmth in the Arctic. This slow-down of the upper-level winds circling the pole has been linked to a Hot Arctic-Cold Continents pattern that brought cold, snowy winters to the Eastern U.S. and Western Europe during 2009 – 2010 and 2010 – 2011.

Figure 3. West-to-east jet stream wind speeds at 500 mb (approximately 18,000 feet or 5,600 meters) in the mid-latitudes (40 – 60°N) over North America between 1948 and 2010. During fall (October – November – December) and winter (January – February – March), jet stream winds weakened by about 20%, from 13 – 14 m/s to 10.5 – 11 m/s. Spring (AMJ) and summer (JAS) winds changed little during this time period.

Arctic sea ice loss may increase the amplitude of jet stream troughs and ridges

The jet stream generally blows from west to east over the northern mid-latitudes, with an average position over the central U.S. in winter and southern Canada in summer. The jet stream marks the boundary between cold polar air to the north and warm subtropical air to the south, and is the path along which rain and snow-bearing low pressure systems ride. Instead of blowing straight west-to-east, the jet stream often contorts itself into a wave-like pattern. Where the jet stream bulges northwards into a ridge of high pressure, warm air flows far to the north. Where the jet loops to the south into a trough of low pressure, cold air spills southwards. The more extreme these loops to the north and south are–the amplitude of the jet stream–the slower the waves move eastward, and consequently, the more persistent the weather conditions tend to be.

A high-amplitude jet stream pattern (more than 1000 miles or 1610 km in distance between the bottom of a trough and the peak of a ridge) is likely to bring abnormally high temperatures to the region under its ridge, and very cold temperatures and heavy precipitation underneath its trough. The mathematics governing atmospheric motions requires that higher-amplitude flow patterns move more slowly. Thus, any change to the atmosphere that increases the amplitude of the wave pattern will make it move more slowly, increasing the length of time extreme weather conditions persist.

Dr. Francis discovered that during the early 1960s, a natural pattern in the atmosphere called the Arctic Oscillation increased the amplitude of the winter jet stream pattern over North America and the North Atlantic by more than 100 miles, increasing the potential for long-lasting weather conditions. The amplitude of the winter jet fell over 100 miles (161 km) during the late 1960s, remained roughly constant during the 1970s – 1990s, then increased by over 100 miles again during the 2000s. This latest increase in wave amplitude did not appear to be connected to the Arctic Oscillation, but did appear to be connected to the heating up of the Arctic due to sea ice loss. A warmer Arctic allows ridges of high pressure to build farther to the north. Since temperatures farther to the south near the bases of the troughs are not changing much by comparison, the result is that the amplitude of the jet stream grows as the ridges of high pressure push farther to the north. Thus it is possible that Arctic sea ice loss and the associated increases in jet stream amplitude could be partially responsible for some of the recent unusual extreme weather patterns observed in the Northern Hemisphere….

Figure 4. A high-amplitude jet stream pattern observed over the U.S. on December 13, 2011. Instead of blowing straight west-to-east, the jet was contorted into a southward-bulging trough of low pressure that brought cold temperatures and a snow storm to Southern California, and a northwards-bulging ridge of high pressure that brought record warm temperatures to portions of the eastern 2/3 of the country. The axis of the jet stream is marked by the strongest winds (green and light blue colors) at the top of the lower atmosphere (200 – 300 mb pressure level.)

Earlier snow cover melt on Arctic land also increases the amplitude of jet stream troughs and ridges

As Earth’s climate has warmed over the past 30 years, the Northern Hemisphere has seen a dramatic drop in the amount of snow cover in spring (April, May, and June.) Spring is coming earlier by an average of three days per decade, and the earlier arrival of spring has significantly reduced the amount of snow on the ground in May. Less snow on the ground means the land surface can heat up more readily, and May temperatures in Arctic have increased significantly over the past 30 years. Dr. Francis found that the upper-level wave amplitude has increased by over 100 miles (161 km) in summer over the past decade, and this change appears to be connected to the decline in May snow cover. Thus, reduced May snow cover due to global warming may be causing higher-amplitude jet stream patterns, potentially leading to slower-moving weather patterns that favor extreme weather in summer, such as heat waves, drought, and flooding. Note that significant changes to the upper-level atmospheric circulation in spring were not observed, so springtime extreme weather events like the 2011 flooding and tornadoes in the U.S. cannot be connected to changes in the Arctic sea ice or high-latitude snow cover using this research.

We are just the beginning of what I expect will be a deluge of analysis on the impact of global warming in general — and Arctic ice loss in particular — on extreme weather.

Related Posts:

 

« »

23 Responses to Arctic Death Spiral: How It Favors Extreme, Prolonged Weather Events ‘Such As Drought, Flooding, Cold Spells And Heat Waves’

  1. Excellent article! And very informative. I’m certain wonks will love this one.

    Just one small nit-pic. We are currently at record lows for sea ice area. Cryosphere Today is showing 2,742,000 square kilometers. This is 163,000 square kilometers below the record and we still have many days left in this melt season.

    Extent is closing and so is volume. Lots of terms. But I think you meant to say extent.

    As for amplifying waves bringing long-term weather patterns… Any research on what this looks like over top of a long-term warming trend. Increases in extreme weather + heating (especially over land masses)?

    One last point and I’m done. The atmospheric pattern emerging in the data appears to be moving more hot air over Greenland…

    Best,

    Rob

  2. BillD says:

    Extreme weather is THE issue with climate change. No one gets worried about an increase of a few degrees in mean temperature. The extremes are what causes economic and ecological damage. I agree with Jim Hansen that scientists have underestimated the effects of anthropogenic climate change on the frequency and intensity of extremes, including heat waves, drought, floods and storms. These links between the arctic and weather in lower latitutes are really important. Scientists need to clarify these links and we need to help journalists and the general public understand what is happening. The extreme weather of the last few years is associated with less than 1 oC of warmer, so it is just the beginning.

  3. Matt says:

    Something has gone haywire with the blog feed!! I was getting the Climate Progress feeds and now suddenly today I am getting EVERY think progress post. Too many! and stuff I’m not interested in. I don’t want to have to cancel.

  4. Leif says:

    People the world over readily accept the scientific fact that changing a patch of South Pacific from warm to cool by only a couple of degrees C, and the resulting comparatively narrow El Nino/La Nina current across the Equatorial Pacific to South America, can have a profound effect on the weather. Not only here in the United States, but to a lesser degree Europe and Africa.
    On the other hand, transforming a much closer, (boarders in many cases), highly reflective patch of earth from significantly bellow freezing to dark open water above freezing, a difference of 10′s of degrees C and it is all cool? Couple that with an area that is larger than the states of Alaska and Texas combined and it is all just going to be “Ho Hum”! Get real. I am telling you, Science is telling you, and the on the ground reality are all raising red flags here. Of course vested interests are spending big bucks trotting out “red herrings” as fast as they can. Perhaps that must be factored into the attitudes of the masses, you think?
    Time to toast the deniers, not the Kidders…

    We all pay fees to dump garbage, waste water and more. Corpro/People dump tons for free and accumulate mega-bucks. Even get tax subsidies. The GOP don’t fund abortion. Fine. A precedent! Why must my tax dollars fund the ecocide of the PLANET via fossil subsidies?!!! We’re talking “MORALS” here. Try throwing 19 pounds of paper cups out the car window for each gallon of gas you burn. Who is making money here and who is losing? Toxins verses paper cups? (I bet you could be real creative about increasing your trash stream if it were paper cups.) Even absorb a “slap on the wrist” fine once in awhile. Surely a good lawyer on retainer. Once established perhaps even a congressman or two.

    I pay $150/ton to dump my household garbage. $50/T to recycle yard waste. Waste water fees, of course. I even have a rain water run of fee of $5/m. (guide lines here?) Yet Corpro/people piss all over themselves at the thought of $25/ton for TOXINS! Sweet Jesus… They are making billions, I get ~$30/day to stay alive and must fund health insurance. Go Figure!

    In brief:

    Stop profits from the pollution of the commons.
    Go Green, Resistance is FATAL!

  5. prokaryotes says:

    Changing Jet Streams May Alter Paths of Storms and Hurricanes

    Hurricanes, whose development tends to be inhibited by jet streams, may become more powerful and more frequent as the jet streams move away from the sub-tropical zones where hurricanes are born. http://www.facebook.com/ClimateState/posts/428878120491682

  6. ColoradoBob says:

    Recently, rains spread to lentil-producing areas of the state, that needed water this season.

    The rains were as high as 248 percent above average in the parched parts of the desert state…………………The city received 160 mm rainfall during two-and-a-half hours of continuous rains on Wednesday.

    http://www.mumbaimirror.com/article/3/2012082220120822161845558f3caae57/Record-rains-bring-Jaipur-to-standstill.html

  7. tamino says:

    The link to Dr. Francis’ article in GRL is broken. If you can restore it, that’d be great — I’d love to read it.

  8. Doug Bostrom says:

    Heads-up that the link to the GRL letter is not working (for me, anyway).

  9. ColoradoBob says:

    Antarctic Peninsula Warms Rapidly … Again

    “We are now approaching the temperatures last seen 12,000 years ago,” he wrote in an email.

    http://www.livescience.com/22593-antarctic-peninsula-warming-record.html

  10. Doug Bostrom says:

    This article sums up what Cliff Mass failed to address in his recent critique of Hansen.

    To be fair to Cliff, when you’re a hammer everything looks like a nail. He’s a meteorologist, not a climatologist.

  11. Long before rising seas levels drive refugees inland, the atmosphere will experience total systemic failure from the point of view of agriculture. It’ll rain where it shouldn’t, when it shouldn’t, in amounts it shouldn’t instead of where, when, and in amounts we’ve come to depend on to feed the 7 billion souls on this planet.

    It’s all about the ice cap. Save the ice cap.

    • Lewis Cleverdon says:

      Raymond – well said.

      By agreeing a UN climate treaty ending our global GHG emissions radically fast – say by 2050 – we then only have another 20 to 40 years of timelagged warming to endure – out to say 2080? – to have successfully ended direct anthropogenic warming.

      Given that ending fossil fuel use ends our maintenance of the cooling ‘Sulphate Parasol’, which Hansen et al report as unveiling an additional 80% to 140% of received warming, temperatures under that successful outcome look a bit severe. – Then there are also the contributions of the seven interactive mega-feedbacks, of which six are already accelerating, and several have the potential to dwarf anthro-emissions.

      I’m all for saving the arctic ice cap, but I think it’s going to take a wholesale review of climate politics and strategies for change, as well as dumping the cosy illusion that rapid emissions control is a sufficient response. Albedo Restoration and Carbon Recovery programs on a commensurate scale are patently necessary for an effective response to the predicament –

      I’d suggest that the sooner this reality is acknowledged and openly discussed, the better our chances of saving the ice-cap, and our societies.

      Regards,

      Lewis

    • Mulga Mumblebrain says:

      Way too late. We can only hope to restore it before the repercussions see us off.

  12. ColoradoBob says:

    Starting on August 13, an unusual low pressure front over the Chukchi Sea poured rain on the Northwest Arctic, especially the area north of Kotzebue, said National Weather Service hydrologist and meteorologist Ed Plumb. The front persisted for a week or so, he said, stuck in the same pattern …………

    The Red Dog Mine area picked up nearly 9 inches of rain between August 13-19, he said. That’s half the rain the area normally gets for an entire year. Last Wednesday, the mine got 3 inches of rain in a single day.

    “It is not unusual to get heavy rains there in August,” he said. “It is unusual to have nearly half of your annual precipitation in a week.”

    Other spots in the region recorded between 4-6 inches of rain over the week, Plumb said.

    Read more here: http://www.adn.com/2012/08/20/2594837/torrential-rains-cause-numerous.html#storylink=cpy

  13. Jack Burton says:

    The vast area of ice in the arctic and Greenland also acts as a stabilizer for climate. When melted the area soaks up sunlight and radiates heat. More heat in the atmosphere, less stable climate.
    Surely the mass of extreme weather events has been piling up over the last decades. The last few years have brought so many extremes that people are becoming numb to the reporting of them.
    Here in North Eastern Minnesota we had an extreme rain event a few months back. Basically a 24 hour thunderstorm and downpour the likes of which no one alive today had ever seen.
    The Great Lake Superior no longer ices up in winter, not even the small harbors freeze up any longer. In the past the great lake was ice bound for months on end. We who grew up in the 60’s have seen such a scale of climate change here as to be undeniable.

  14. nyc-tornado-10 says:

    The arctic ice is approaching a 50% loss of area from the 1980 – 2000 average, based on the university of illinois – cryosphere today group, and the other measurements of area and extent are also pointing to a near 50% loss of arctic sea ice from the norms of the late 20th century. The melting of arctic ice is probably accelerating, which means that the disastrous shift in weather patterns we have seen, especially in the last 3 years, will get much worse in the coming years, this is scarey, to say the least.

  15. Aleph Null says:

    Thanks for the extensive excerpt of Masters’ superb explanation. Though he didn’t once mention “Rossby waves,” I think I’m starting to understand the connection Francis draws.

    Some folks have the impression it’s about polar bears and harp seals. I don’t want to trivialize the destruction of Arctic ecosystems, but the vanishing sea ice is a curtain rising on a novel climate regime for the entire northern hemisphere. This is indeed the story of the decade.

    • John McCormick says:

      Aleph, implications for Arctic sea ice melting can reach as far as South Asia. Scientists are trying to understand the recent erratic arrival time and intensity of Asian Monsoon and are beginning to draw connections with the Arctic. Stay tuned. 2 billion people are dependent upon certainty of the monsoon.