Sunday, July 8, 2012

Slow Warming Trend (this summer: hotter than the Dust Bowl years of the 1930s?)

90 F. high temperature Sunday in the Twin Cities.

84 F. average high for July 8.

91 F. high temperature on July 8, 2011.

17 days at or above 90 F. so far in 2012.

13 days at/above 90: average for a summer season in the Twin Cities.

25-30 days: my prediction for the number of 90+ days this year. Hope I'm wrong.

12 of the hottest years on record, worldwide, occured in the last 15 years. Source: NASA Goddard Space Center.

Sunday Records. Details from NOAA, via Facebook: "More record high temperatures set today across the southern portion of the Eastern Region. Raleigh NC reached 105 again, tying the all time record high temperature last set on June 30th. It was also the 6th consecutive 100 degree day at Raleigh, also a record. Fortunately cooler air will continue to push south on Monday. The threat for severe weather on Monday will also be further south into Virginia and North and South Carolina."

10 Consecutive Days Above 100 F. at St. Louis. It was the second longest stretch of 100+ heat, second only to 1936. Details below from NOAA:


 1  13  8/24/1936
 2  10  7/07/2012
 3   9  7/17/1936
 4   8  7/24/1934
T5   7  8/02/1953
T5   7  8/09/1930
 7   6  7/14/1966
T8   5  7/23/1983
T8   5  6/29/1952
T8   5  8/06/1947

64 days above 100 F. in the Twin Cities since 1873. Source: Minnesota Climatology Working Group.

13 counties in northeastern Minnesota declared Federal Disaster Areas. $108 million in damage to public property. Source: Star Tribune.

98% The Waldo Canyon Blaze outside Colorado Springs is now 98% contained - details from The Denver Post.

Pavement-Melting Heat: US Airwaves Plane Gets Stuck In "Soft Spot" On Pavement At Washington Reagan. I've never seen this before - a plane getting stuck in hot asphalt. Here's an excerpt from The Washington Post: "Things were proceeding normally Friday evening as a US Airways flight was leaving the gate at Reagan National Airport to begin its flight to Charleston, S.C. But the temperature reached 100 degrees in Washington on Friday and that apparently softened the airport paving enough to immobilize the airplane. The small vehicle that usually tows planes away from the gate tugged and pulled, but the plane was stuck."

Photo credit above: Phillip Dugaw. "Phillip Dugaw's airplane to Charlston, S.C. got stuck in a soft spot caused by the heat on the tarmac at Reagan Airport on Friday. The photo went viral after he posted it to Reddit."

Temporary Relief. Not heat warnings, watches or advisories? The USA gets a break through midweek, but heat is forecast to build again by late week. Map above: NOAA.

"New McCarthyism" Described By Climate Scientist Michael Mann. ABC News reporter Bill Blakemore has an eye-opening series on the threats, from the public - and misguided, fossil-fuel-funded political ideologues. Can this really be happening in the USA in 2012?
Slow Warming Trend. No more 100s in sight looking out 7-10 days, but after a comfortable Monday & Tuesday (mid 80s) the mercury warms to 90 by late week, possibly low to mid 90s by the weekend. ECMWF solution above.

Unrelenting Heat Wave Bakes All Within Its Reach. The New York Times has the story; here's an excerpt: "...In the Midwest, some residents were drawing comparisons between the current heat wave and the severe heat and drought of the 1930s. More than 420 deaths were recorded during a 1936 heat wave in St. Louis, which also saw 153 heat-related fatalities during a 14-day period in 1980. Around the region, corn and soybean crops shriveled from the heat and the lack of rain. In the hardest hit and hottest areas, some farmers said they had already given up on their cornfields for the season. Others say much is riding on whether the heat subsides and rain arrives in the next few days, a crucial period for corn pollination. “There’s vast uncertainty,” said Bob Nielsen, a professor of agronomy at Purdue. “There aren’t many years, though, when I get this pessimistic.” Meteorologists said the recent hot streak, though not unprecedented, was unusual because of how early in the summer it struck and its duration."

* map above showing Saturday highs courtesy of NOAA and Ham Weather.

Lightning And Thunder Send Rangers And Twins Running For Cover (Video). Not sure why they didn't call the game earlier. The Twins have their own on-staff meteorologist at every home game (Craig Edwards, former chief of the local Twin Cities office of the National Weather Service), keeping an eye on Doppler. Apparently the Rangers do not have anyone keeping an eye on radar. Here's an explanation and video clip of the mayhem from "Sunday night's Texas Rangers game in Arlington against the Minnesota Twins was delayed abruptly due to a sudden arrival of thunder and lightning, sending both teams and the umpires running for cover."

* more details on the meteorological scare at Ranger Park from The Star Telegram.

"Historically, Minneapolis/St. Paul has experienced an average of 12 days per summer over 90 and less than 2 days over 100. Under the higher-emissions scenario, the Twin Cities could experience nearly 70 days above 90°F toward the end of the century and 28 days over 100. Under the lower-emissions scenario, the Twin Cities would experience a little more than 30 days over 90 and 7 days over 100, on average." - from a recent UCS (Union of Concerned Scientists) press release.

"At some point...extreme weather events will have become sufficiently common to convince any person of reason that global warming has begun." - from a story on climate change by Doug Craig at below.

Over 2,200 Record Highs In The Last Week. All those red dots are record highs, yellow dots are record (warm) nighttime lows. Map courtesy of NOAA and Ham Weather. Details:

Total Records: 3932
Rainfall: 305
High Temp: 2210
Low Temp: 74
Low Max Temp: 132
High Min Temp: 1211

Most 100-Degree Days Since 1988. Here is a statement from The Minnesota Climatology Working Group: "For the second time in a week, the mercury hit 100 degrees or higher at the Twin Cities International Airport. The last time there were two 100 degree maximum temperatures in the Twin Cities was 1988, when there were four. July 1-6, 2012 will also finish the warmest first six days of July on record in the Twin Cities with a preliminary average of 87 degrees F, higher than the next closest average (July 1-6 1949) with 84.2 degrees F. It's been relatively uncommon to see the mercury reach 100 at the Twin Cities International Airport in recent years. Before 2011, the last time the maximum temperature was 100 degrees or more was on July 31, 2006 when the air temperature reached was 101 degrees. Looking back to 1873, the maximum temperature at the Twin Cities official measuring site has reached 100 or more on 64 occasions. The most was in 1936 with nine days. The last year with more than one 100 degree temperature was in 1988 with four.

Hot Holding Pattern. The 6-10 Day Extended Temperature Outlook from NOAA's Climate Prediction Center (CPC) shows a lingering warm bias over the northern tier states into mid-July, the greatest anomalies over Idaho and Montana, but temperatures running 5-10 F. above average across Minnesota and northern Wisconsin. Map courtesy of Ham Weather.

5-Day Rainfall: All or Nothing. The drought continues to worsen across the Midwest and Ohio Valley, where dry weather will be the rule this week. Meanwhile some 5-7" rains are predicted from Houston and Nashville to Charlotte, along the leading edge of cooler, Canadian air pushing south, taking the edge off the heat over the northern third of the USA. QPF map courtesy of NOAA HPC.

The Longest, Hottest Heat Wave. D.C. Records 9th Straight 95+ Day. Some amazing details on the (historic) heat wave from The Washington Post's Capital Weather Gang: "For the 9th straight day, Washington, D.C. has met or exceeded 95 degrees (officially 95 at 11:25 a.m., 96 is the high so far today). In 141 years of records, this is a first. And the streak is likely to be extended to 11 after Saturday and Sunday. This record is just one of countless extraordinary heat records established over the course of the last three summers."

Graphic credit above: "Number of consecutive days at or above 95 degrees in Washington, D.C. since 1872." (Ian Livingston)

Redefining Hot. From NOAA in Washington D.C.:

"The earliest reported reading of 100 F. in a calendar day was recorded yesterday, July 6, 2012...just before 12 pm noon EDT, or 11 am Eastern Standard Time. Previously the earliest record of a 100 F. reading in Washington D.C. was August 21, 1930 at noon EST, or 1 pm EDT. The most number of consecutive hours of 100 F or better in Washington is 7 hours. This has occurred twice...once on July 21, 1930 from noon to 6 pm EST...the other was yesterday, July 6, 2012 from noon to 6 pm EDT.

From The Capital Weather Gang:

5:40 pm update: The weather observer at National Airport reports the temperature did hit 106 F. for one minute. That would have tied D.C.'s all-time high, but it has to last for at least 3 minutes to count. So today's official high will go down as 105 F, breaking the previous July 7 record of 102 F. in 2010. Also, Dulles tied its record high for the date with a high of 101 F, while BWI broke its record high for the date with a high of 103 F.

8:25 pm update: It's likely we've established at least two additional records today at Reagan National. 1) Highest low temperature for the date of 82, two degrees above the old record of 80 from 2010 (assuming it doesn't drop below that before midnight). 2). Highest average temperature for any calendar day on record (all-time) of 94 F.

Gridlock: Storms, Blackouts Expose Power Problems. Our infrastructure is increasingly vulnerable to blackouts from super-sized thunderstorms, as explained in this NPR article; here's an excerpt: "As hundreds of thousands swelter without power a week after a violent storm pummeled the Midwest and Mid-Atlantic, energy experts say the future will look even worse if the nation's aging, congested electrical grid isn't upgraded. Customers chafe at rising utility bills, but the energy industry warns that the alternative is even scarier: Unless $673 billion is invested in the system, it could break down by 2020, according to an American Society of Civil Engineers report released in April. The grid's dependability has become an increasing concern as the system strains to meet increased demand. Bottlenecks in the grid and equipment failures are causing more brownouts and blackouts, energy experts say."

Photo credit above: Monte Draper/AP. "A power pole is bent after severe storms hit the Bemidji, Minn., area on Tuesday, knocking down thousands of trees and causing extensive damage to utility lines. Thousands of customers were left without power."

Forecaster: London Weather "Can't Get Any Worse". Olympic organizers are watching the weather maps, hoping a (very) pattern breaks before the games kick off in a couple of weeks. Details via YouTube: "Organizers and visitors are keeping their fingers crossed for summer weather during the London 2012 Olympics. The UK is currently languishing in a trough of low pressure, and has just seen the wettest June on record. (July 6)."

Tornado Hunting: Chasing Storms For The Perfect Picture. Here's a terrific photo essay from WJLA-TV in Washington D.C.: "As one of North America’s premier storm-chasers, Greg Johnson captures some of nature’s most terrifying yet beautiful weather phenomenons . Last year, Johnson traveled over 30,000 miles to find the perfect moment to click his camera during each perfect storm. Greg Johnson has been chasing storms for over a decade. He photographs everything from thunder and lightning storms, tornados, hurricanes and blizzards. This gallery is full his favorites. Hope you enjoy the chase!"
Photo Of The Day: "Undulatus Asperatus". Thanks to Paul Schroeder for sending in an amazing example of undulatus asperatus, which is a recently discovered cloud type, an exotic wave cloud formed by extreme turbulence and temperature inversions (temperatures warming with altitude). He snapped this photo near Hayward, Wisconsin Saturday morning.

Cumulonimbus. Thanks to Paul Brooks, a prolific storm chaser, who heads up PBrooks Photography. A link to the photo and his company via Facebook. This shot was taken north of Bennett, Iowa.

Is Your Computer Infected Wit DNS Malware? I know, I was skeptical too (more like paranoid to click on anything I don't know or trust), but this is a legitimate concern, and using the link below you can (safely) check your PC or Mac to see if you're infected.

"Ask Paul". Weather-related Q&A:

Today's highlighted question is a good one: how do we (as meteorologists) grade ourselves? How does "verification" really work? Every meteorologist, to some degree or another, uses their own metrics to evaluate what they believe to be an accurate forecast. If you're withing 2-3 F. of the predicted temperature, that usually fits the definition of an accurate forecast. Precipitation is much trickier, especially in summer. If the forecast calls for "partly sunny with isolated thundershowers" and it doesn't rain at your house, but a town 10 miles away gets dumped on, is that an accurate forecast? All weather is local. Everyone cares about their home, their neighborhood, but during a typical summer afternoon it may only rain on 10-30% of the state.

Mr. Paul Douglas,

"I read your narrative in the StarTribune June 22, 2012 weather column.  You stated that the national accuracy for a 24-hour forecast is 87%.  This prompted me to reach back and read a paper I wrote in Feb 1999 that looked at a small slice of weather data for the previous year.  That paper was written in response to similar accuracy questions I had at the time.  I still have the same questions today.  For instance, what weather variable(s) does the 87% refer to? - high temperatures, low temperatures, humidity (dew factor), sun, wind, rain, etc?.  Under what parameters is the accuracy calculated?

I have attached the paper (Weather.docx) and and some supporting graphs (hi_lo_tm.xlsx) based on the data I collected.  I know you are a very busy man, but I hope you will find time to read the paper and comment on my questions above

Thank You,
Warren Banks

Warren - thanks for your note and the work you put into the white paper/spread sheet. The 87% number is the generally agreed upon metric for 24 hour accuracy (averaging all forecasts, NOAA and private sector). I can't find a paper or link to support that number, but I've heard it batted around now for nearly 30 years - and (interestingly) ithat 87% number hasn't improved during that period, in spite of (significant) gains for Day 2-7. I forwarded your question to the local NWS office in Chanhassen and here is their response:

"We use a few different methods internally to try and gauge our accuracy. The forecasters look at verification information frequently, since it is tough to improve if one doesn't know how well he/she is doing. Plus, we view detailed verification of the various model guidance, since knowing what is working best makes it easier for us to do well, since we can work from the "best" starting point. The majority of our verification is now done in a gridded manner, such that we verify things at each 2.5x2.5 km. grid box for which we produce a forecast (for the National Digital Forecast Database). The "truth" which we verify against is a combination of the Real-Time Mesoscale Analysis (RTMA) combined with all available observations (METARS, mesonet data, etc). 

In the past, verification was only done for specific points, and could be misleading on how the overall forecasts were performing across the entire area. For temperatures, a common metro we use to judge our accuracy is the measure of the percentage of the entire forecast area (evaluated at each grid point) for which the error is <3 degrees F. As an example, over the past 30 days, our forecasts (MPX) for our area for low temperature the following night (i.e. the forecast issued today for tomorrow night) have had an overall error of <3 degrees F for 70.1% of the area, with 0% having an error >10 F. 

For the day seven forecast, over the past 30 days, the area with error of <3 F was 34.2% and the error of >10 degrees F was 11.7% These are just quick examples, but should give you some idea of things we commonly look at to quickly assess our accuracy with respect to temperatures. For the probability of precipitation, the thing we consider most frequently is the "reliability" metric, which essentially provides information on what percenage of the time a given probability occurs. Perfectly calibrated POP's would result in a situation when measurable precipitation occurs 20% of the time that 20% POPs are forecast, 50% of the time 50% POPs are forecast, and 100% of the time 100% POPs are forecast."

Tom Hulquist, NOAA (Twin Cities office)

Experimental Headlight Can See Through Rain And Snow. I thought this story from was interesting; here's an excerpt: "Driving at night in falling rain or snow can be treacherous, but not just because the asphalt is slippery – visibility is also greatly reduced, as the driver’s view of the road ahead is obscured by brightly headlight-lit raindrops or snowflakes. In the future, however, that may not be so much of a problem. A team led by Carnegie Mellon University’s Prof. Srinivasa Narasimhan has developed an experimental headlight system that renders most foreground precipitation virtually invisible, while still adequately illuminating the road beyond."

Forget The Ice Cream Truck, This One Makes Wood-Fired Pizzas! This might work in....California? Details from "Del Popolo’s is a traveling pizza truck located in San Francisco, that features an impressive wood-fired pizza oven. The mobile restaurant has been constructed from a recycled shipping container which has been completely remodeled to include a modern kitchen workspace and two large glass doors that open out to the public."

Is Your Computer Infected? I know - it sounds like one of those scams you DON'T want to click on, but this is legit. According to the FBI there is a lot of malware out there that may prevent hundreds of thousands of Internet users from accessing the web on Monday. To see if your computer is infected click here (I did it with my PC - no problems). It's a little additional peace of mind on a Sunday. Service provided by (Thanks Pete!)

Great Story-Telling Advice (From A Pixar Pro). Here's an excerpt of a terrific story about...storytelling, from an employee of a company that has turned it into a true artform, Pixar - from the Wall Street Journal (subscription may be required): "For the past five years, Pixar has served as my film school. As a storyboard artist, working mainly on "Brave" but more recently on other projects, I had the privilege to collaborate with an incredible creative team. As we hashed out the details of our narrative, I learned a lot about the basics of storytelling, and I have used Twitter to share them with others. Here's some of what I've road-tested from my work trying to bring Princess Merida, other Pixar characters and my own creations to life. 

1. You admire characters more for trying than for their successes.
2. Remember that what's interesting to an audience can be very different from what's fun to do as a writer."

19 Thoughts About Finding Your Purpose. I found this simple - yet profound. Here's an excerpt from

"Those who win are producers, not consumers. The first thing you do each morning should be active, not passive– no Facebook, no email. Whatever you choose should put you in a state of mind for the rest of the day. Choose carefully.

The goals others set for you are usually wrong. The people who give them to you seem well meaning, and they have more experience, too. But your heart will guide you better than anyone. Find internal markers to know if what you’re doing is right.

If you do two things at once, one of them is getting done wrong. No matter how wrong you think this is, or how many exceptions you think there are… I sincerely doubt it."

Warm, But Less Humid. A few instability showers and T-showers did pop up over central Minnesota Sunday afternoon, affecting less than 3% of the state. A northwest breeze dropped dew points into the upper 50s, making a 90 degree high in the Twin Cities tolerable. Elsewhere highs ranged from a comfortable 70 at Grand Marais to 87 Alexandria; 90 at St. Cloud

Paul's Conservation Minnesota Outlook for the Twin Cities and all of Minnesota:

TODAY: Fresh air. Sunny and pleasant. Dew point: 58. Winds: NW 10-15. High: 85

MONDAY NIGHT: Clear, still comfortable. Low: 64

TUESDAY: Blue sky. Perfect. Dew point: 60. High: 86

WEDNESDAY: Sunny, more humid. Dew point: 63. Low: 67. High: 88

THURSDAY: Partly sunny. Sticky. Dew point: 65. Low: 68. High: 89

FRIDAY: Hazy, spotty T-storms up north? Dew point: 67. Low: 69. High: 90

SATURDAY: Hot sun, humid with a few late thundershowers? Dew point: 69. Low: 71. High: 94

SUNDAY: Partly sunny, muggy and unsettled; a few T-storms. Dew point: 70. Low: 72. High: 92

Cabin Therapy

“Perhaps the truth depends on a walk around the lake” wrote American poet Wallace Stevens. Perhaps. The hypnotic lapping of water...a soundtrack of laughter and loon calls. My blood pressure drops 20 points up at the cabin.

I get it now.

Oceans are great, until jellyfish bite and hurricanes rage. Western mountains are wondrous, until they catch on fire. I'll take a Minnesota lake any day of the year. If only they were maintenance-free.
16 days above 90 this summer. Average is 13. At the rate we're going, with a hot high pressure bubble perpetually stalled over the Plains, pushing waves of sizzling, overheated air north, we may wind up with 25+ days at or above 90F this summer.

June brought 3,215 record highs nationwide - the USA may wind up with the hottest summer on record, possibly hotter than the Dustbowl Days of the 1930s. Drought is deepening over the Midwest and Ohio Valley; the Corn Belt is getting fried.

A dry week is shaping up; the first chance of late-day storms next weekend, as highs reach 90-95F.
It seems extra heat and humidity is spiking T-storms, making straight-line winds stronger. No derechos in sight for Minnesota - just fresh, Canadian air into midweek. By next weekend we get another (slightly milder) taste of heat and humidity - still steamy enough to get your attention.

Climate Stories....

We're Already Topping Dust Bowl Temperatures - Imagine What Will Happen If We Fail To Stop 10 F. Warming. Here's an excerpt of a post from Joe Romm at Think Progress: "This heat wave has broken thousands  of temperature records. Climate Central reported Satuday, “In many cases, records that had stood since the Dust Bowl era of the 1930s have been equaled or exceeded, and this event is likely to go down in history as one of America’s worst.” In general, we expect the greatest number of temperature records to be set during a widespread drought. I explained why that is that the case in my Nature article last year on “The next dust bowl” (full text here):"
"Warming causes greater evaporation and, once the ground is dry, the Sun’s energy goes into baking the soil, leading to a further increase in air temperature. That is why, for instance, so many temperature records were set for the United States in the 1930s Dust Bowl; and why, in 2011, drought-stricken Texas saw the hottest summer ever recorded for a US state."

Michael Mann - Bill Blakemore ABC News On Climate Change And The Global Warming Disinformation Campaign. Here's a terrific 5-part series, courtesy of "In an extended interview posted today, Bill Blakemore at ABC News talks with scientist Michael Mann, author of The Hockey Stick and the Climate Wars, about the global warming disinformation campaign, attacks on climate scientists (from Congress to hate mail), the shortcomings of media coverage, the influence of the fossil fuel interests, and the growing urgency of action to limit the damage from anthropogenic global climatic disruption. Links to video and transcript below."

Part 1:  ‘New McCarthyism’ Described by Climate Scientist Michael Mann
Part 2:  Climate Denialists Worse Than Tobacco CEOs Lying Under Oath, Says Mann
Part 3:  Climate Denialists Would Be Remembered as Villains, Says Mann
Part 4:  Unprecedented Crisis for Humanity — But There’s Hope
Part 5:  Climate ‘Groundhog Day for Scientists and Journalists Alike 

Conspiracy Theorist + Global Warming Denialist. The Missing Link Defined? Here's an excerpt from a fascinating, if troubling, story from "When questioning media elite about how they give strong voice to anti-science global warming denialism, one of my (and others’) favorite analogies has been with those who believe the moon landings were faked in the desert. As per a years-ago letter published in the Washington Post,"
"This brings to mind the fact that about 15 percent of Americans believe that the Apollo moon missions never occurred and were staged on movie sets in the desert. Would The Post, in reporting on the space program, seek to be fair and balanced by giving this 15 percent a voice equal to that of astronauts, astronomers and academic experts? Why, then, give prominent voice to global-warming deniers, who are similarly at odds with facts?"

Climate Change Cowardice From Chicago Weather Anchors. Yes, TV meteorologists should be talking about climate change, because it's now impossible to separate out weather from climate. A warmer (wetter) atmosphere is providing the background hum, the atmospheric-Muzak, that is responsible for the radicalization of our weather, heavier rain storms, more intense drought, and hotter heat waves. To ignore the elephant in the living room is not only perpetuating ignorance, but against official AMS statements that link increasingly extreme weather with a warming atmosphere. Here's an excerpt from The Daily Kos: "I generally enjoy the WTTW PBS program Chicago Tonight, but their guests on Friday made me wonder if I had accidentally turned to Fox News. The program promised "three local weather experts discuss Chicago’s 2012 weather trends: a mild winter, a spring heat wave, and a hot, dry summer." The host, Joel Weisman, raised the question of weather patterns gently at first. When none of the guests took the bait, he pushed them more directly by bringing up climate change. The meteorologists reacted as though someone had dropped a turd in the middle of the room. Turning away, throwing up their hands and groaning, it was obviously the last thing they wanted to talk about. Phil Schwarz of ABC-7 first brought up the "natural cycles" argument that climate change deniers have retreated to since the global trend is now undeniable. He claimed that whether man-made pollutants are causing the problem is the topic of debate. Next someone suggested that climate trends are regional and that harsh winters in some areas somehow disprove the fact that we're experiencing a global phenomenon."

Cartoon Credit: "This Pat Bagley editorial cartoon appears in The Salt Lake Tribune on Sunday, July 8, 2012."

What Global Warming Looks Like. Here's part 2 of a thoughtful 4 part series on our recent spate of extreme weather and a link with climate change, from Doug Craig at "Seth Borenstein, an Associated Press writer, published a piece on Independence Day with this lead: "If you want a glimpse of some of the worst of global warming, scientists suggest taking a look at U.S. weather in recent weeks." He also wrote, "These are the kinds of extremes climate scientists have predicted will come with climate change, although it's far too early to say that is the cause. Nor will they say global warming is the reason 3,215 daily high temperature records were set in the month of June." But look it this way. If you are making soup, you can make it without salt or with a little or a lot of salt. Each decision will affect the taste. Human activity is to our climate like salt is to soup. Once you add salt and mix it in, every spoonful contains a little of that extra flavor. Same with our climate. We have added enough extra CO2 and methane and various other greenhouse gases to permanently alter the Earth's atmosphere. Every inch of sky bears our brand."

Union of Concerned Scientist Press Release. Here is a press release from The Union of Concerned Scientists that arrived Friday. I was going to provide an excerpt, but this is too important to chop up and edit. So I'm including the entire statement from UCS:

Heat waves and climate change
As heat-trapping emissions from burning coal and gas and destroying tropical forests continue to pile up in the atmosphere, the Earth’s average temperature increases and with it, the likelihood that extreme heat events will occur.

Over the last decade, the United States has set twice as many record highs as record lows. Because warmer air can hold more moisture, heat indices, which measure what it actually feels like to be outside, are also increasing. Meanwhile, the number of extreme heat events globally has increased and in the United States, there has been an increase in high-humidity heat waves characterized by high nighttime temperatures.

Cities are particularly vulnerable to extreme heat, in part, because dark, heat-absorbing asphalt and heat-trapping buildings are so prevalent. Over the past fifty years, smaller cities have seen extreme heat events increase by an average of almost six days per year, while larger cities have seen an increase of about 15 days.

Future projections of extreme heat nationally
According to a U.S. government scientific assessment, dramatically reducing emissions would limit average warming in the United States to between 4 and 7 degrees Fahrenheit by the end of the century. But staying on a business as usual path would lock in 7 to 11 degrees of warming. The assessment projected that staying on our current path would make extreme heat events that occurred just once every twenty years in the past happen every other year or annually throughout the country by the end of the century.

Over the very long term, higher temperatures could make it very difficult, if not impossible, for people to tolerate the outdoor heat during the hottest months of the years in many parts of the world. The emissions choices we make today will determine whether or not such scenarios will remain on the table.

Extreme heat is an economic and public health threat
People’s health is most at risk from basic heat stress, which can result in hospitalizations and death. Extreme heat is also a catalyst for increased ground-level ozone pollution -- or smog -- which can cause breathing problems and exacerbate asthma.

Heat also can drive spikes in energy demand as people crank up their air conditioners. During the 2011 heat wave, peak power prices in affected areas jumped from $100 per megawatt hour to $350. Such increases translate to hefty electricity bills for consumers. Additionally, heat stresses electricity grids, lowering their efficiency and increasing equipment failures.

When it comes to agriculture, extreme heat can dampen productivity for crops and cattle. Extreme heat can drag down yields for corn, soybean, wheat and cotton. For livestock, extreme heat can sap milk production as much as fifty percent, lower the rate at which livestock gain weight, and greatly reduce reproduction rates.

North America was hit hard in 2011, with the kind of heat wave that is more likely in a changing climate

For the United States, 2011 was the hottest summer since the Dust Bowl. Forty-two states had above-normal temperatures for the summer months and 4 states broke records for extreme summer heat. During a July heat wave, the National Weather Service had issued heat alerts for areas home to approximately 141 million people.

The National Climatic Data Center estimates that the combination of heat, wildfires and drought in the Southwest and Southern Plains resulted in $12 billion worth of damage, including damage to agricultural and livestock production.

Preparing for a future of heat stress
Americans can build resilience to climate change consequences and take aggressive measures to reduce our carbon emissions and the risks of climate change. Because a certain amount of climate change is already locked in for the next few decades, we will have to cope with the impacts of extreme heat on our daily lives, our health and on our economy. Preventative public health measures and local preparedness are critical for protecting public health and saving lives. But in order to effectively prepare for the impacts of climate change, we need a comprehensive national strategy to create climate-resilient communities and reduce the emissions that are driving climate change.

Extreme heat projections for select Midwest States and Cities
Confronting Climate Change in the U.S. Midwest, a 2009 UCS analysis, included heat projections for nine Midwest cities based on two future emissions scenarios. The analysis also included projections for how the summer-time climates of two states – Illinois and Michigan – would “migrate.” Below are summaries of that information and links to relevant charts and graphics.
By the end of the century, under a lower-emissions scenario Illinois’s summer-time climate is projected to be more like Arkansas and Louisiana’s while under a higher-emissions scenario it would more closely resemble Texas. Illinois “migrating state” map.

By the end of the century, under a lower-emissions scenario, Michigan’s summer-time climate is projected to resemble Tennessee, Missouri and Arkansas’ climate. Under a higher-emissions scenario, it would be more like Oklahoma’s. Michigan “migrating state” map.

Historically, Chicago has experienced an average of 15 days per summer over 90 and about 2 days per year over 100. Under the higher-emissions scenario, Chicago could experience more than 70 days above 90°F toward the end of the century and 30 days over 100. Under the lower-emissions scenario, the city would experience less than 40 days over 90 and 8 days over 100, on average.

Historically, Cincinnati has experienced an aver­age of more than 18 days per summer with highs over 90 and less than 2 days over 100. Under the higher-emissions scenario, Cincinnati is projected to experience more than 85 days over 90°F—nearly the entire summer—and 29 days over 100 by the end of the century. Under the lower-emissions scenario, Cincinnati would experience less than 50 days over 90 and 8 days over 100, on average.

Historically, Cleveland has experienced an aver­age of 9 days per summer with highs over 90 and less than 1 day over 100. Under the higher-emissions scenario, Cleveland is projected to experience more than 60 days over 90 and 21 days over 100. Under the lower-emissions scenario, Cleveland would experience less than 30 days over 90 and 5 days over 100, on average.

Des Moines:
Historically, Des Moines has experienced an average of 22 days per summer over 90 and less than 2 days over 100. Under the higher-emissions scenario, Des Moines could experience more than 85 days above 90°F toward the end of the century and more than 30 days over 100. Under the lower-emissions scenario, the city would experience less than 50 days over 90 and only 9 days over 100, on average.

Historically, Detroit has experienced an average of 10 days per summer over 90 and less than 1 day over 100. Under the higher-emissions scenario, Detroit could experience almost 65 days per summer with highs above 90°F toward the end of the century and 23 days above 100. Under the lower emissions scenario, the city would experience less than 30 days above 90 and 5 days over 100, on average.

Historically, Indianapolis has experienced an average of 17 days per summer over 90 and less than 1 day over 100. Under the higher-emissions scenario, Indianapolis could experience over 80 days above 90°F toward the end of the century and 28 days over 100. Under the lower-emissions scenario, the city would experience 40 days over 90 and 7 days over 100, on average.

Historically, Milwaukee has experienced an average of 9 days per summer over 90 and less than 1 day per year over 100. Under the higher-emissions scenario, Milwaukee could experience more than 55 days per summer with highs above 90°F toward the end of the century and 22 days over 100. Under the lower-emissions scenario, the city would experience less than 30 days over 90 and 5 days over 100, on average.

Minneapolis/St. Paul:
Historically, Minneapolis/St. Paul has experienced an average of 12 days per summer over 90 and less than 2 days over 100. Under the higher-emissions scenario, the Twin Cities could experience nearly 70 days above 90°F toward the end of the century and 28 days over 100. Under the lower-emissions scenario, the Twin Cities would experience a little more than 30 days over 90 and 7 days over 100, on average.

St. Louis:
Historically, St. Louis has experienced an average of 36 days per summer above 90 degrees and less than 3 days over 100. Under the higher-emissions scenario, St. Louis could experience 105 days above 90°F toward the end of the century and 43 days above 100. Under the lower-emissions scenario, the city would experience a little more than 60 days over 90 and 11 days over 100, on average.

Aaron Huertas
Press Secretary, Union of Concerned Scientists
Washington D.C.

No comments:

Post a Comment