extreme weather

Extreme Weather and Resilience: An Ounce of Prevention

A recent Senate hearing highlighted some of the progress U.S. communities are making, and the major challenges they face, in better coping with costly extreme weather events — including those, such as heat waves and coastal flooding, whose risks are heightened by climate change.

Sen. Tom Carper, chairman of the Homeland Security and Governmental Affairs Committee, noted that the “frequency and intensity of these extreme weather events are costing our country a lot - not just in lives impacted – but in economic costs, as well.” Nearly 130 weather-related events in 2013 caused more than $20 billion in losses in the United States.

Extreme weather is costly, not only to federal, state, and local governments, but also to businesses and individuals.

Much of the Senate testimony echoed key findings in our report, “Weathering the Storm, Building Business Resilience to Climate Change.”  Three key points made at the hearing were:

The State of the Climate

As President Barack Obama prepares to deliver his State of the Union address, we believe it’s a good time to take a look at the state of our climate: the growing impacts of climate change, recent progress in reducing U.S. emissions, and further steps we can take to protect the climate and ourselves.

The consequences of rising emissions are serious. The U.S. average temperature has increased by about 1.5°F since 1895 with 80 percent of this increase occurring since 1980, according to the draft National Climate Assessment. Greenhouse gases could raise temperatures 2° to 4°F in most areas of the United States over the next few decades, bringing significant changes to local climates and ecosystems.

Chilling out on the Polar Vortex

This week’s brief but bitter cold snap over more than half the country prompted intense discussion about the polar vortex ranging from educational to bombastic.

Figure 1: A depiction of the “average” polar vortex on Jan. 6. The winds of the vortex correspond to the narrow “rainbow” areas. The map is an average of the upper atmosphere’s “topography” (specifically, the 500 millibar height) from all the January 6ths between 1980 and 2010.
Figure 2: The polar vortex on Jan. 6, 2014. The ridge (“R”) and trough (“T”) responsible for relatively warm weather in much of the West and bitterly cold weather in the Midwest and East have been labeled.

So let’s be clear: The cold snap this week was unusual but not entirely unprecedented. A few super-cold days don’t disprove global warming, just like a day of rain doesn’t end a drought. At the same time, we don’t yet know whether climate change will change the odds of future outbreaks of bitter cold. Research is still underway, and as of now, we shouldn’t necessarily expect these events to be more or less frequent in future winters. 
Here’s a Q&A to cut through the hype:

  • What is the polar vortex?  The polar vortex describes the air circulating aloft (thousands of feet above the ground) about the North Pole, and its extent is marked by a ribbon of strong winds that is often called the “jet stream.” (We most commonly focus on the North Pole, but a similar circulation is present around the South Pole, too).
    In the map (Figure 1), which is from the point of view of the North Pole, the vortex corresponds to purple and blue colored areas. The band where the colors change from blue/purple to red/yellow indicates the location of the jet stream, or the outer edge of the vortex. Winds are strongest where this color gradient is tightly packed (e.g., over the Pacific Ocean and North Atlantic Ocean). It tends to be quite cold at the surface below the purple areas, and warmer under the red/yellow areas.

It’s important to note that this figure is an average of many winter days. On any given day, we would see a number of deviations from this average pattern.

  • What happened this week? Comparing this week (Figure 2) to the average picture (Figure 1), we can see that the purple area of the vortex has contorted and moved farther south. Along with this pattern, there are substantial “wiggles” in the jet stream. These deviations in the circulation helped bring cold air into the continental United States that normally stays in northern Canada and the Arctic. Meteorologists look for these wiggles, called “ridges” and “troughs” (“R” and “T” on the map)  when putting together a forecast. While the trough brought notable cold to the Midwest and the East, the ridge has kept parts of the West warmer than average and relatively dry (much to the dismay of skiers).

Tornadoes and Climate Change

What causes a tornado?

Tornadoes are formed by a combination of atmospheric instability and wind shear.  Instability occurs when warm, moist air is wedged under drier, cooler air aloft. This warm air rises, causing the intense updrafts and downdrafts seen in strong thunderstorms — the incubators of tornadoes. Wind shear refers to changes in wind direction and speed at different elevations in the atmosphere. The combination of instability and wind shear forms the circular air flow that generates a tornado.

Why are there so many in the U.S. Midwest?

The Central United States has an abundance of the ingredients necessary for tornado formation. During the spring, warm tropical air masses from the Gulf of Mexico collide with colder, drier air at higher altitudes to spawn intense thunderstorms. Thunderstorms also form into the summer and fall, as the region’s vast plains heat up air near the surface, causing atmospheric instability. These intense thunderstorms act as incubators for tornadoes. Tornadoes occur around the world but are most common in “Tornado Alley” of the Central United States.

Is there a link between climate change and tornadoes?

It is important to keep in mind that climate change has an impact on all weather events.  The effect of the carbon dioxide in our atmosphere cannot be switched off – it influences our seemingly benign “everyday” or “normal” weather as well as the extreme events. 

A specific link between tornadoes and climate change, however, is unclear. It is difficult to identify and diagnose trends in long-term records of tornadoes, since the population in many areas affected by tornadoes has grown (e.g., tornadoes in the early part of the 20th century may have occurred without anyone seeing them) and the technology used to observe tornadoes has improved (e.g., radars help us “see” tornadoes in ways that were not possible many decades ago).

How could climate change affect the frequency or intensity of tornadoes?

Researchers are working to better understand how the building blocks for tornadoes -- atmospheric instability and wind shear -- will respond to global warming. It is likely that a warmer, moister world would allow for more frequent instability. However, it is also likely that a warmer world would lessen chances for wind shear. Recent trends for these quantities in the Midwest during the spring are inconclusive. It is also possible that these changes could shift the timing of tornadoes or regions that are most likely to be hit.

Adding to the difficulty, tornadoes are too geographically small to be well simulated by climate models. Models can simulate some of the conditions that contribute to forming severe thunderstorms that often spawn tornadoes. Multiple studies (e.g., here and here) find the conditions that produce the most severe thunderstorms are likely to occur more often in the in a warmer world, even if the total number of thunderstorms decreases (because of fewer weak storms). However, this work does not conclusively tell us whether tornadoes should follow the same trend as their parent thunderstorms.

Extreme Weather

Extreme Weather Event Map: Click on any circle to learn about one of the billion-dollar weather events, or any state to learn about billion-dollar droughts. All events occurred between 2000 and 2013.

>$50 billion
$20-$50 billion
$5-$20 billion
$2-$5 billion
< $2 billion
(Note: circle sizes correspond to the map view of the continental U.S.)

This map shows billion-dollar weather events in the United States since 2000, as identified by the National Oceanic and Atmospheric Administration’s National Climatic Data Center. The Top 10 costliest events are listed at the bottom of this page, along with a description of major U.S. droughts since 2000.

Floods, Tornadoes, Thunderstorms, Hail, Tropical Storms, Wildfires, and Winter Storms are all shown as circles, with the costs indicated by the area of the circles (see image to the right).  The location of the circles correspond to places where impacts were experienced (note: locations are approximate; many of the events actually impacted a large area, beyond
the boundaries of the circle). Droughts are not shown by circles, but by the shading in the states – states with darker colors have experienced more droughts since 2000, while states that are lightly shaded have experienced fewer droughts. No billion dollar events have occurred in Hawaii since 2000; some of the wildfire impacts (e.g., fire seasons in 2006, 2007, and 2008) included damages in Alaska, but the markers appear in the continental United States.

Many of these events, including heat waves and heavy rainfall, are likely to become more frequent and intense as a result of climate change. Climate change can also worsen the impacts of some of these events. For example, sea level rise can increase the impacts of coastal storms and warming can place more stress on water supplies during droughts. But it’s important to note that not ALL of these events will necessarily happen more frequently as a consequence of climate change. The links between climate change and tornadoes, ice storms, and hail are unclear, and represent current areas of research.

These events demonstrate ways our communities and infrastructure are vulnerable to extreme weather, and that the costs associated with impacts can be large.

More Resources on Extreme Weather and Climate Change

Fact Pages: Learn more about the links between climate change and:

 

Weathering the Storm - Extreme weather is costly. The events shown on the map above all cost billions of dollars, and several events had widespread and long-lasting implications.

C2ES has investigated how companies are perceiving the risks associated with extreme weather and climate change. Focusing on Standard and Poor’s (S&P) Global 100 companies, we found that 90 percent of these companies identify extreme weather and climate change as risks, and most have experienced climate impacts or expect to within 10 years. Although some companies have taken action, only a few have used climate-specific tools to comprehensively assess risks and develop resilience plans. Check out the report to learn more, and to learn about the steps business and government can take to close the resilience gap.

 

Related Blogs

 

Table 1: Top 10 Disasters by Cost Since 2000
Event and DateCostFatalitiesDescription
Hurricane Katrina
August 2005
$148 billion1,833The hurricane initially hit as a Category 1 near Miami, FL, then as a stronger Category 3 along the eastern LA-western MS coastlines, resulting in severe storm surge damage (maximum surge probably exceeded 30 feet) along the LA-MS-AL coasts, wind damage, and the failure of parts of the levee system in New Orleans. High winds and some flooding occurred in Ala., Fla., Ga., Ind., Ky., Miss., Ohio and Tenn.
Hurricane Sandy
October 2012
$65.7 billion159Sandy caused extensive damage across several northeastern states (Conn., Del., Mass., Md., N.J., N.Y., R.I.) due to high wind and coastal storm surge, particularly in N.J. and N.Y. Damage from wind, rain and heavy snow also extended more broadly to other states (N.C., N.H., Ohio, Pa., Va., W.Va.), as Sandy merged with a developing Nor'easter. Sandy interrupted critical water and electrical services in major population centers and caused 159 deaths (72 direct, 87 indirect). Sandy also shut down the New York Stock Exchange for two consecutive business days, which last happened in 1888 due to a major winter storm.
Drought
2012
$30.0-$30.3 billion123The 2012 drought was the most extensive in the U.S. since the 1930s. Moderate to extreme drought conditions affected more than half the country for a majority of 2012. Costly impacts included widespread harvest failure for corn, sorghum and soybean crops, among others. The associated summer heat wave also caused 123 direct deaths, but the excess mortality due to heat stress is still unknown.
Hurricane Ike
September 2008
$29.2 billion112Ike made landfall in Texas as a Category 2 hurricane. It was the largest Atlantic hurricane on record by size, causing a considerable storm surge in coastal TX and significant wind and flooding damage in Ark., Ill., Ind., Ky., La., Mich., Mo., Ohio, Pa., Tenn. and Texas. Severe gasoline shortages occurred in the Southeast due to damaged oil platforms, storage tanks, pipelines and refineries.
Hurricane Wilma
October 2005
$19 billion35The Category 3 hurricane hit SW Florida, resulting in strong damaging winds and major flooding across southeastern Florida. Prior to landfall, Wilma as a Category 5 recorded the lowest pressure (882 mb) ever recorded in the Atlantic basin.
Hurricane Rita
September 2005
$19 billion119The Category 3 hurricane hit Texas-Louisiana border coastal region, creating significant storm surge and wind damage along the coast, and some inland flooding in the Fla. panhandle, Ala., Miss., La., Ark., and Texas. Prior to landfall, Rita reached the third lowest pressure (897 mb) ever recorded in the Atlantic basin.
Hurricane Charley
August 2004
$18.5 billion35The Category 4 hurricane made landfall in southwest Florida, resulting in major wind and some storm surge damage in FL, along with some damage in the states of S.C. and N.C..
Hurricane Ivan
September 2004
$17.2 billion57The Category 3 hurricane made landfall on Gulf coast of Ala., with significant wind, storm surge, and flooding damage in coastal Ala. and Fla. panhandle, along with wind/flood damage in the states of Ga., Miss., La., S.C., N.C., Va., W.Va., Md., Tenn., Ky., Ohio, Del., N.J., Pa., and N.Y.
Drought
2011
$12.0-$12.4 billion95In Texas and Oklahoma, a majority of range and pasture lands were classified in "very poor" condition for much of the 2011 growing season.
Hurricane Frances
September 2004
$11.1 billion48The Category 2 hurricane made landfall in east-central Fla., causing significant wind, storm surge, and flooding damage in FL, along with considerable flood damage in the states of Ga., N.C., N.Y. and S.C. due to 5-15 inches of rain.

 

Table 2: Drought Events since 2000

YearCostFatalitiesDescriptionStates Affected
2013N/A53The 2013 drought slowly dissipated from the historic levels of the 2012 drought, as conditions improved across many Midwestern and Plains states. However, moderate to extreme drought did remain or expand into western states. In comparison to 2011 and 2012 drought conditions the US experienced only moderate crop losses across the central agriculture states.Ariz., Calif., Colo., Idaho, Kan., Neb., Nev., N.M., Okla., Ore., S.D., Texas, Utah, Wyo.
2012$30.0-$30.3 billion123The 2012 drought was the most extensive drought to affect the U.S. since the 1930s. Moderate to extreme drought conditions affected more than half the country for a majority of 2012. Costly drought impacts occurred across the central agriculture states resulting in widespread harvest failure for corn, sorghum and soybean crops, among others. The associated summer heatwave also caused 123 direct deaths, but an estimate of the excess mortality due to heat stress is still unknown.Ariz., Ark., Calif., Colo., Ga., Idaho, Ill., Ind., Iowa, Kan., Minn., Mo., Mont., Neb., Nev., N.M., N.D., Okla., S.D., Texas, Utah, Wyo.
2011$12.0-$12.4 billion95Drought and heat wave conditions created major impacts for affected areas. In Texas and Oklahoma, a majority of range and pastures were classified in "very poor" condition for much of the 2011 crop growing season.Ariz., Kan., La., N.M., Okla., Texas
2009$5.0-$5.4 billion0Drought conditions occurred during much of the year across parts of the Southwest, Great Plains, and southern Texas causing agricultural losses in numerous states. The largest agriculture losses occurred in Texas and California.Ariz., Calif., Kan., N.M., Okla., Texas
2008$2.0-$2.2 billion0Severe drought and heat caused agricultural losses in areas of the South and West. Record low lake levels also occurred in areas of the Southeast.Calif., Ga., N.C., S.C., Tenn., Texas
2007$5.0-$5.6 billion15Severe drought with periods of extreme heat over most of the Southeast and parts of the Great Plains, Ohio Valley, and Great Lakes area reduced crop yields, stream flows and lake levels.Ala., Ark., Fla., Ga., Ill., Ind., Iowa, Kan., Ky., La., Mich., Minn., Miss., Neb., N.Y., N.C., N.D., Ohio, Okla., Pa., S.C., S.D., Tenn., Texas, Va., W.Va., Wis.
2006$6.0-$6.9 billion0Severe drought affected crops in the Great Plains and across portions of the South and far West.Ala., Ark., Calif., Colo., Fla., Ga., Iowa, Kan., La., Minn., Miss., Mo., Mont., Neb., N.M., N.D., Okla., S.D., Texas, Wyo.
2005$1.0-$1.2 billion0Severe localized drought caused significant crop losses, especially for corn and soybeans.Ark., Ill., Ind., Mo., Ohio, Wis.
2002$10.0-$12.9 billion0Moderate to extreme drought was experienced over large portions of 30 states, including the West, Great Plains, and much of the eastern U.S.Ala., Ariz., Calif., Colo., Conn., Del., Fla., Ga., Idaho, Iowa, Kan., La., Maine, Md., Mich., Miss., Mo., Mont., Neb., Nev., N.J., N.M., N.C., N.D., Ohio, Okla., Ore., Pa., R.I., S.C., S.D., Texas, Utah, Va., Wyo.
2000$4.0-$5.4 billion140Severe drought and persistent heat over south-central and southeastern states caused significant losses to agriculture and related industries.Ala., Ariz., Ark, Calif., Colo., Fla., Ga., Idaho, Iowa, Kan., La., Miss., Mont., Neb., Nev., N.M., N.C., Okla., Ore., S.C., Tenn., Texas, Utah, Wash., Wyo.

 

On our own?

Spring not only brings us daffodils and cherry blossoms in Washington, D.C., but also occasionally powerful thunderstorms that can knock out power to thousands of homes and businesses.

I live in one of those northern and western suburbs of DC that tend to lose power fairly frequently.

It used to be that one of the few nice things about losing power was the sound of silence. But those days are gone. Now losing power has a new sound: the whirring of the startup of my neighbors’ backup generators.

We need power not only to keep our food from spoiling and protect us from uncomfortable and even dangerous heat, but also to stay connected. As a nation, we are becoming ever more dependent on electronic devices. We cannot survive without our cell phones and computers, let alone our refrigerators and air conditioners. At the same time, climate change threatens the reliability of the grid through more intense heat waves and potentially more powerful storms.

While it’s easy to say we should work to prevent disruption in electricity, how much should we invest to bolster the resilience of the grid? And who should pay?

How climate change amplified Sandy’s impacts

As Hurricane Sandy moves out of the region, people in affected areas are beginning to take stock of the damage. Flooding in parts of New Jersey and New York from the storm surge hit record levels. The 13.8-foot surge measured at Battery Park in Lower Manhattan surpassed the all-time record of 11.2 feet set in 1821, flooding the New York subway system and two major commuter tunnels.  Along the Eastern Seaboard, an estimated 7.5 million people lost power. Farther inland, blizzard conditions dropped as much as 2 feet of snow as Sandy crashed into arctic air over the Midwest. While early estimates indicate direct damages from the hurricane may be as much as $20 billion, the total economic losses, including losses in consumer and business spending, could be more than twice that amount.

A number of climate change-related factors may well have intensified the storm's impact: higher ocean temperatures, higher sea levels, and an atmospheric traffic jam that may be related to Arctic melting.  Hurricane Sandy is also a clear reminder of how vulnerable our homes and infrastructure already are to extreme weather — and this risk is growing.

Increasing extreme weather is costly in many ways

A report released this week by two senior members of Congress notes that the unusual number of extreme weather events in 2012 has cost the country billions of dollars and that the unusual frequency of these events is consistent with what scientists have predicted from climate change.

The staff report, “Going to Extremes: Climate Change and the Increasing Risk of Weather Disasters” is from the offices of Reps. Edward Markey (D-MA) and Henry Waxman (D-CA), the prime movers behind the last attempt at significant climate legislation. It cites information from a variety of sources, including NOAA, the news media and the private sector to show how rising weather risk costs real money.  

Their report comes a week after Congress headed home for the elections having accomplished very little to address climate change. Nearly half the bills introduced by the current Congress would block or hinder climate action, though none of these have been enacted into law.

C2ES Releases New Extreme Weather Map on Eve of Senate Climate Hearing

Press Release
July 31, 2012

Contact: Laura Rehrmann, 703-516-0621, rehrmannl@c2es.org

 
C2ES Releases New Extreme Weather Map on Eve of Senate Climate Hearing

The Center for Climate and Energy Solutions (C2ES) has created a new online map providing an overview of extreme U.S. weather events since 1990. The map highlights examples of extreme heat, heavy precipitation, drought, and wildfire -- four types of events with clear trends connected to climate change.

In a blog post announcing the new map, C2ES science and policy fellow Dan Huber summarizes the recent run of extreme weather:

“Climate change is elevating the risk of extreme weather,” writes Huber. “It’s crucial that we take stock of what each disaster teaches us so that we understand the rising risks and are better prepared for what’s to come.”

The science behind climate change will be the focus of a hearing tomorrow (Wednesday, Aug. 1) before the Senate Environment and Public Works Committee titled “Update on the Latest Climate Change Science and Local Adaptation Measures.” The hearing, set for 10 a.m. in 406 Dirksen, is the Senate’s first in this Congress focusing directly on climate change science.

For more information:

Extreme weather map: http://www.c2es.org/science-impacts/extreme-weather

Climate Compass blog: http://www.c2es.org/climatecompass

Follow @C2ES_org on Twitter or #epwclimatehearing.

Contact Senior Communications Manager Laura Rehrmann at rehrmannl@c2es.org to arrange an interview with a C2ES expert.

About C2ES: The Center for Climate and Energy Solutions (C2ES) is an independent non-profit, non-partisan organization promoting strong policy and action to address the twin challenges of energy and climate change. Launched in November 2011, C2ES is the successor to the Pew Center on Global Climate Change.

Mapping extreme weather across the U.S.

Today we’re updating our online map providing an overview of extreme weather events in the United States since 1990.  The map highlights memorable examples of extreme heat, heavy precipitation, drought, and wildfire, four types of events with clear trends connected to climate change.

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