NOAA Bombshell: Warming-Driven Arctic Ice Loss Is Boosting Chance of Extreme U.S. Weather

Two new studies make a strong case that global warming is driving an intensification of high-pressure anomalies that in turn make North American weather more extreme. They add to a growing body of scientific observation and analysis on the connection between man-made climate change and extreme weather — and disasters.

So I can say, not coincidentally, Munich Re, the world’s largest reinsurance company is releasing a report next week based on its natural catastrophe database — the most comprehensive of its kind in the world — that concludes:

  • Global warming is driving an increase in weather-related disasters
  • North America is the continent with the largest increases in disasters.

And so I can also say, not coincidentally, NOAA’s National Climatic Data Center (NCDC) reported Tuesday in its “State of the Climate” for September that the Climate Extremes Index for the period January-through-September was over the highest ever — and over twice the average value — since record-keeping began in 1910.

NOAA’s Climate Extremes Index (year-tod-date) is at the highest level ever.

We appear to have a perfect storm: Detailed observations of more extreme weather in North America in recent years are now coming at the same time as new scientific analyses that can explain why manmade climate change is boosting extreme weather in our continent.

The two new studies are “The recent shift in early summer Arctic atmospheric circulation” (subs. req’d, news release here) and “Intensification of Northern Hemisphere subtropical highs in a warming climate” (subs. req’d, news release here). The latter Nature Geoscience study is closely related to a 2010 Journal of Climate study that found “global warming is the main cause of a significant intensification in the North Atlantic Subtropical High (NASH) that in recent decades has more than doubled the frequency of abnormally wet or dry summer weather in the southeastern United States.”

The first study is related to another 2012 Geophysical Research Letters study, “Evidence linking Arctic amplification to extreme weather in mid-latitudes,” which found that the loss of Arctic ice favors “extreme weather events that result from prolonged conditions, such as drought, flooding, cold spells, and heat waves.”

What makes this study a bombshell is that it is led by our very own National Oceanic and Atmospheric Administration (aka NOAA), which put out a news release explaining how global warming drives extreme weather in North America:

“Our research reveals a change in the summer Arctic wind pattern over the past six years. This shift demonstrates a physical connection between reduced Arctic sea ice in the summer, loss of Greenland ice, and potentially, weather in North American and Europe,” said [NOAA’s James] Overland, an oceanographer who leads the laboratory’s Coastal and Arctic Research Division.

The shift provides additional evidence that changes in the Arctic are not only directly because of global warming, as shown by warmer air and sea temperatures, but are also part of an “Arctic amplification” through which multiple Arctic-specific physical processes interact to accelerate temperature change, ice variability, and ecological impacts.

I discuss “Arctic amplification” in a September post on the “Arctic Death Spiral.”

The NOAA release explains:

Higher pressure over the North American continent and Greenland is driving these changes in the early summer wind patterns,” said Edward Hanna, Ph.D, of the University of Sheffield.

These shifts in winds not only affect weather patterns throughout the Arctic but are also thought to influence weather in Greenland, the United States, and western Europe. Understanding such links is an ongoing area of research, the scientists said. The effects of Arctic amplification will increase as more summer ice retreats over coming decades. Enhanced warming of the Arctic affects the jet stream by slowing its west-to-east winds and by promoting larger north-south meanders in the flow. Predicting those meanders and where the weather associated with them will be located in any given year, however, remains a challenge.

The researchers say that with more solar energy going into the Arctic Ocean because of lost ice, there is reason to expect more extreme weather events, such as heavy snowfall, heat waves, and flooding in North America and Europe but these will vary in location, intensity, and timescales.

“What we’re seeing is stark evidence that the gradual temperature increase is not the important story related to climate change; it’s the rapid regional changes and increased frequency of extreme weather that global warming is causing. As the Arctic warms at twice the global rate, we expect an increased probability of extreme weather events across the temperate latitudes of the northern hemisphere, where billions of people live,” said Jennifer Francis, Ph.D, of Rutgers.

For more detail on the connection between warming-driven ice loss and extreme weather, see How the Arctic Death Spiral Favors Extreme, Prolonged Weather Events and “Is Climate Change Bringing the Arctic to Europe?


Arctic Sea Ice is melting much, much faster than even the best climate models had projected. The reason is most likely unmodeled amplifying feedbacks. Image via Arctic Sea Ice Blog.

What’s fascinating about Hanna’s statement that “higher pressure over the North American continent and Greenland is driving these changes in the early summer wind patterns,” is how it might connect to the second study.

As the news release for that study — “Weather-Making High-Pressure Systems Predicted to Intensify” — explains:

High-pressure systems over oceans, which largely determine the tracks of tropical cyclones and hydrological extremes in much of the northern hemisphere, are likely to intensify this century, according to a Duke University-led study published online this week in Nature Geoscience.

The study’s findings suggest that as summertime near-surface high-pressure systems over the northern Pacific and Atlantic oceans strengthen, they could play an increasingly important role in shaping regional climate, particularly the occurrence of drought and extreme summer rainfall, in coming years….

According to the simulations, these high-pressure systems will intensify over the 21st century as a result of increasing greenhouse-gas concentrations. The simulations suggest that an increase in the land-sea thermal contrast – the difference between ocean and land heating, as Earth’s climate warms – will fuel the systems’ intensification.

For more on this study, see Climate Central’s piece, “Global Warming May Shift Summer Weather Patterns.” They quote study coauthor Mingfang Ting of Columbia University, “The intensification and westward movement of the subtropical highs may cause more landfalling hurricanes/typhoons and cause more intense Southeast U.S. rainfall variability, leading to more extreme events in the[se] regions.” They also noted, “Recent summers have seen dramatic flips between punishing droughts and severe flooding in states such as Georgia, for example.”

THE BOTTOM LINE: We are playing with the climate system in ways that are already starting to bite us and may ultimately consume us — or at least our food supply — whole (see “Climate Story of the Year: Warming-Driven Drought and Extreme Weather Emerge as Key Threat to Global Food Security“).

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20 Responses to NOAA Bombshell: Warming-Driven Arctic Ice Loss Is Boosting Chance of Extreme U.S. Weather

  1. The vulnerability of agriculture to the diminishing ice cap is becoming more and more apparent. That risk, far more than the risk of sea level rise, should be the focus of efforts to persuade leadership of the urgency of reducing GHG emissions.

    The disappearance of the ice cap, even just for a few weeks, could abruptly destabilize the jet stream and the seasonal highs and lows it’s in such close dynamic with. I don’t think it’s too crazy to imagine that North America could have a sudden, broad, and catastrophic crop failure across multiple agricultural categories that fateful summer. We might get through one year with stored food, but what about the next? Suddenly, the implications of summer after ineluctable summer of crazy, unpredictable weather will become obvious even to the most oblivious.

    Ultra-conservative deniers, especially. They’re angry and blameful by nature. That will make them very angry and blameful indeed.

    Our already polarized society could quickly find itself in a lifeboat-type situation with genuine food shortages, not merely high prices. It doesn’t take that much imagination to understand that the destabilization of the jet stream will be paralleled by the destabilization of our democracy.

    And with all the surveillance technology in place, and the broad anti-terrorist laws, and deep suspicions about political motives, some very nasty things could happen.

    Save the ice cap.

  2. Flakmeister says:

    We are so fooked….

  3. Richard Miller says:


    Any thoughts on how this new research relates to the work on drought by Aiguo Dai, which you have covered before?

    Here is a brief summary statement by Dai in the NYTimes.

    In essence, I think the U.S. has been very fortunate to have experienced a wetting trend from the 1950s to the 1990s, in contrast to many other low- and mid-latitude land areas. However, this luck is about to run out, because the tropical Pacific sea surface temperatures apparently switched into a cold phase around 1999 that typically lasts for 20-30 years and brings below-normal precipitation and drought over much of the West and southern U.S. On top of that, the greenhouse-gas-induced global warming is predicted to cause severe drying in the coming decades over the U.S. Even if the tropical Pacific condition changes after 1-2 decades into a warm phase, the U.S. is unlikely to return the wet conditions of the 1977-1999 because of the expected large drying from global warming.

  4. john c. wilson says:

    What stored food? There isn’t much. Once the shortage occurs it will be global, all food in storage will be coveted. Allocating such food as there is will be intensely political, but that phase won’t last long.

    Basically we make each and every harvest a big one or TSHTF.

  5. Joan Savage says:

    “What we’re seeing is stark evidence that the gradual temperature increase is not the important story related to climate change;

    it’s the rapid regional changes and increased frequency of extreme weather that global warming is causing.” – Dr Jennifer Francis

    This is the huge educational message to get across.

    By the time the AVERAGE global temperature rises one more degree Celsius, the Arctic will have warmed much more than that.
    has a simple graphic, though surely there are other sources.

  6. Tim says:


    I know you’re interested in communication – hence your recent book, Language Intelligence. I don’t know if you touched upon it your book (I haven’t read it yet), but this post illustrates the power of a well-done graphic. The “You are here 2012” figure is my update (sent to Neven at the Sea Ice Blog) of a figure I saw in one of Peter Sinclair’s Climate Crocks videos (his was “You are here 2011”). That struck me as a masterfully effective way to communicate a couple of very important things:
    (1) Sea Ice melting is indeed proceeding at an alarming pace, and
    (2) Far from being “alarmists”, most climate modelers have been, intentionally or not, very conservative.

    BTW, though I read this blog often, in this case I came via a Google News link. I hope Sinclair’s excellent (updated) graphic had a bit to do with that.

  7. Raul M. says:

    It’s October 11th and the temperature reports during the evening at multiple cities in Greenland are above freezing. It is a very very big change for multiple cities in Greenland to have a winter that is several months shorter than normal? Is several months shorter winter to be expected for the coming years? Hard to talk about the weather without noticing the rapid and widespread warming.

  8. Omega Centauri says:

    There is some, then some high quality stores, like meat on the hoof are culled during times like now when feed is expensive. This introduces lags. Also cutting the fraction of calories supplied from meat could go a long ways.
    I don’t think developed world people will be starving. But, they may be paying more, and famine pressure may destabilize poorer countries and create instability. I expect these indirect effects will be more important for rich world folks.

  9. Mulga Mumblebrain says:

    I reckon Greenland will melt ultra-rapidly, shocking everyone. And the IPCC Report of 2030 will predict its imminent melting, sometime around 3000, as the waves lap over Shanghai, New York and London.

  10. Jeremy says:

    Just read that the volume of Arctic sea ice was 50% less than 2007 in the summer!
    This has caused PANIC among some scientists and they are bringing up geo-engineering to buy us a little more time.
    Funny the CEO of Exxon-Mobile, rex Tillerson, suggested the same.

  11. “I don’t think developed world people will be starving.”

    I wouldn’t be so sure. What’s that meat on the hoof going to eat if there is a severe grain shortage? Remember, each time you move up a notch in the food chain, you lose 20-30 percent of the calories contained in the lower trophic level. Also, in the case of industrial beef, there are energetic costs in producing the food and shipping it to the feed lots. It will be hard to justify feeding cows when people are hungry. (It already is, but most of the hungry people are out of sight or out of the U.S.)

    Finally, the industrial food chain is critically time dependent — a rapid, systemic crop failure could crash the whole system.

  12. Ellie Cohen says:

    Excellent summary- thank you so much Joe.

    We need a better name for the reality of climate change. Even climate disruption is too hard to remember and say (per your excellent communications guidelines in your new book).

    I suggest an alliteration to communicate what it really is:


    However, we are still missing ocean acidification in this– the other 800 lb. gorilla sitting on our backs. Driven by increased CO2 by not by climate….

  13. Mulga Mumblebrain says:

    In the UK, the poor, whose ranks are burgeoning under the class hatred and blows of ‘austerity’, are being forced, by rapidly rising food prices, to give up fruit and vegetables and rely more and more on cheap junk. Some families already see the parents fasting to ensure that the children are fed. Malnourishment, leading to chronic illness in adulthood, is already a reality, and it will get worse. There is no ‘developed world’, there are developed countries where inequality, poverty and misery are growing like topsy, thanks to the evil intent of capitalists to steal from the many to enrich the few.

  14. Mulga Mumblebrain says:

    I prefer Climate Apocalypse, because it gives the religious nutters on the Right what they crave and it represents the end-stage before the Final Judgment on the evil that is capitalism.

  15. Spike says:

    Yes the UK is still highly dependent on food imports and to add to our troubles has fewer farmers and many more mouths to feed than the last time we had a major food crisis in the dark days of the Battle of the Atlantic. These are interestingly being featured in a BBC series looking at how we pulled through:

    At that time though there were still politicians of integrity and courage,strong leaders such as Churchill, a govermnment committed to serving all the citizenry not ignoring what one minister recently referred to scathingly as the “plebs”, and a more cohesive and co-operative society. There was less corporate control of the food chain too.

  16. Spike says:

    Oh and in the UK Food Banks are already at their busiest ever in recent history thanks to the ideological assault on the poor. Here’s what one christian charity has to say:

    “Foodbanks across the UK are experiencing their highest ever demand. This harvest could you, your school, church or business collect non-perishable food for your nearest foodbank to help stop people going hungry?
    Trussell Trust figures released this week show that foodbanks fed 128,697 people nationwide in the last financial year, compared to 61,468 in 2010-11: an increase of 109%. Many of those helped were families struggling as a result of rising food and fuel prices combined with static incomes, high unemployment and changes to benefits. 45,898 children have been fed in the last 12 months.”

  17. Sharon Christians says:

    What is all this scientific evidence, debate and discussion doing to influence policy, public and private, toward reducing manmade greenhouse gas emissions, which finally have been acknowledged as the root cause of manmade climate change. The facts are before us. What is our collective response? The search for more fossil fuels underneath the newly revealed waters of the Arctic? Why not take all the grants, subsidies, tax incentives that have driven this entire industry of climate research and energy exploration to change the game? Incentivize a paradigm shift toward solutions and alternatives. Not confirmation and more of the same.

  18. Essentially, it is correct to say that high pressure areas are driving the system but the real story is more likely the change over the Arctic ocean. It used to be a high pressure area of falling winds which spread out over the surrounding land and kept it frozen. Now with more heat gathered by an ever more open ocean, if it becomes an area of rising air (low pressure area) it will suck weather patterns northward and descimate the crop growing areas of the northern hemisphere. By the time we learn to farm the new conditions, we may be well on our way to the lovelock number (1b people on earth)
    The jet stream reminds me of a top that is beginning to wobble as it slows down just before it tips over.

  19. bob says:

    Since the planet is a closed system where does all this incremental water come from to raise sea levels by up to 6 feet? I’m not a scientist so i get to asked what some may deem a stupid questions. I know ice is denser than water so as ice melts there would be some incremental water in liquid form but 6 feet given the levelized impact across the great oceanic expanses seems hard to believe.

  20. Joe Romm says:

    Land-locked ice. Greenland, Antarctic.