by Andrew Freedman, Alyson Kenward and Mike Lemonick, cross-posted from Climate Central

Texas, Alabama and Missouri topped the list of states hardest hit by the unrelenting assault of extreme weather in 2011.

Severe weather across much of the nation has raised the question of whether global warming has already begun to influence shorter-term weather patterns, and the specter of even more extreme years to come as global temperatures continue to rise.

According to climate studies, the short answer is yes: the new climate environment created by global warming is more conducive to some extreme events, particularly heat waves and heavy precipitation events: these are now more likely to occur and be more intense when they do take place. Climate models have more difficulty predicting how climate change may be influencing other types of extremes, such as severe thunderstorms and tornadoes, but a warming climate provides more fuel to these events in the form of increased water vapor and heat in the atmosphere.

And those extreme events — searing heat waves, parching drought, deadly tornadoes, blizzards and floods — cost billions of dollars in damage, affected millions of lives and tragically, killed more than a thousand people across the U.S.

By some measures, 2011 was the most extreme year for the U.S. since reliable record-keeping began in the 19^thcentury — and the costs have been enormous: according to the National Oceanic and Atmospheric Administration (NOAA), 2011 set a record for the most billion dollar disasters in a single year. There were 12, breaking the old record of nine set in 2009. The aggregate damage from these 12 events totals at least $52 billion, NOAA found.

While extreme weather knows no boundaries, and the impact of those events was felt coast to coast, Climate Central looked at the number of extreme events that affected each state to determine the 10 states that were clobbered the worst. According to Climate Central’s analysis, Texas tops that list of hardest hit, with a costly — and deadly — combination of intense drought, a punishing heat wave, the worst wildfires in state history, and plenty of tornadoes. Rounding out the top 10 was Alabama, Missouri, North Carolina, Oklahoma, Tennessee, Kansas, Connecticut, Vermont and New Jersey.

Climate Central’s analysis factored the death toll in each state, damage costs, the disruption caused to daily life, and how unusual the events were compared with what transpires in an average year.

But for these 10 states, little of what transpired was average as extreme weather rewrote the record books in 2011.

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Mainstream news outlets spent a lot of time in 2011 covering the record-breaking year for extreme weather in the U.S. But only a few of them spent much time exploring the link between those events and global warming (see With No End in Sight for Texas Drought, ABC News Explains: “Every Farmer in the World Will Be Affected by Climate Change” and links below).

So PBS deserves a special mention for a segment that aired yesterday looking at how global warming is influencing extreme weather events. As Jeff Masters, co-founder of the Weather Underground (and periodic contributor to this blog) explained in the piece: “They all tend to get increased when you have this extra energy in the atmosphere. I call it being on steroids … for the atmosphere.”

Watch the full segment:

Watch How 2011 Became a ‘Mind-Boggling’ Year of Extreme Weather on PBS. See more from PBS NewsHour.

And here’s the transcript:

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– by Jeff Masters in a Wunderblog repost

“The question is not whether sea ice loss is affecting the large-scale atmospheric circulation…. It’s how can it not?” That was the take-home message from Dr. Jennifer Francis of Rutgers University, in her talk “Does Arctic Amplification Fuel Extreme Weather in Mid-Latitudes?”, presented at last week’s American Geophysical Union meeting in San Francisco.

Dr. Francis presented new research in review for publication, which shows that Arctic sea ice loss may significantly affect the upper-level atmospheric circulation, slowing its winds and increasing its tendency to make contorted high-amplitude loops. High-amplitude loops in the upper level wind pattern (and associated jet stream) increases the probability of persistent weather patterns in the Northern Hemisphere, potentially leading to extreme weather due to longer-duration cold spells, snow events, heat waves, flooding events, and drought conditions.

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.

Summertime Arctic sea ice loss: 40% since 1980

The Arctic has seen a stunning amount of sea ice loss in recent years, due to melting and unfavorable winds that have pushed large amounts of ice out of the region. Forty percent of the sea ice was missing in September 2007, compared to September of 1980. This is an area equivalent to about 44% of the contiguous U.S., or 71% of the non-Russian portion of Europe. Such a large area of open water is bound to cause significant impacts on weather patterns, due to the huge amount of heat and moisture that escapes from the exposed ocean into the atmosphere over a multi-month period following the summer melt.

Figure 2. The extent of Arctic sea ice loss in the summer July – August – September period in 2007 was about 1.4 million square miles (3.6 million square kilometers) greater than in 1980, according to the University of Illinois Cryosphere Today. For comparison, the lost ice coverage (orange colors) was equal to an area about 44% of the size of the contiguous U.S., or 71% of the non-Russian portion of Europe.

Arctic sea ice loss can slow down jet stream winds

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Figure 1. Departure of precipitation from average for 2011, as of December 6, 2011.  Remarkably, more than half of the country (56%) experienced either a top-ten driest or top-ten wettest year, a new record. Image credit: NOAA/HPC.

– Dr. Jeff Masters in a WunderBlog repost (with added material at the end)

This year is now the wettest year in nearly 200 years of record keeping in Philadelphia, Pennsylvania. A large, wet low pressure system soaked the Northeast U.S. on Wednesday and early Thursday, bringing 2.31 inches of rain to the City of Brotherly Love, bringing this year’s precipitation total in Philly to 62.26 inches. This breaks the old yearly precipitation record of 61.20 inches, set in 1867. In a normal year, Philadelphia receives about 40 inches.

According to wunderground’s weather historian Christopher C. Burt, this is one of the most difficult U.S. city records to break, since rainfall records in Philadelphia go back to 1820. The only other sites with a longer continuous precipitation record in the U.S. are Charleston, SC (1738 -) and New Bedford, MA (1816 -).

20+ inches above average precipitation in Ohio Valley, Northeast

Philadelphia is not alone in setting a wettest year in recorded history mark in 2011. Over a dozen major cities in the Ohio Valley and Northeast have set a new wettest year record, or are close to doing so. Thanks to rains associated with this year’s tremendous tornado outbreaks in April in May, plus exceptionally heavy summer thunderstorm rains, combined with rains from Tropical Storm Lee and Hurricane Irene, portions of at least twelve states have seen rains more than twenty inches above average during 2011.

The fraction of the country covered by extremely wet conditions (top 10% historically) was 32% during the period January through November, ranking as the 2nd highest such coverage in the past 100 years. And if you weren’t washing away in a flood, you were baking in a drought in 2011–portions of sixteen states had precipitation more than twenty inches below average (Figure 1.)

The fraction of the country covered by extremely dry conditions (top 10% historically) was 22% during the period January through November, ranking as the 8th highest in the past 100 years. The combined fraction of the country experiencing either severe drought or extremely wet conditions was 56% averaged over the January – November period–the highest in a century of record keeping [see Figure 2 below].

Climate change science predicts that if the Earth continues to warm as expected, wet areas will tend to get wetter, and dry areas will tend to get drier–so this year’s side-by-side extremes of very wet and very dry conditions should grow increasingly common in the coming decades.

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Yale released the above chart in November (which I posted at the time).  Now they have released “the second and third reports from our latest national survey on Americans’ climate change and energy beliefs, attitudes, policy support, and behavior.”  Key findings:

• Public understanding that global warming is happening stayed at 63 percent, while belief that it is caused mostly by human activities increased three points since May 2011, to 50 percent.
• A majority of Americans (57%) now disagree with the statement, “With the economy in such bad shape, the US can’t afford to reduce global warming” – an 8 point increase in disagreement since May 2011.
• 65 percent said that global warming is affecting weather in the United States.
• 58 percent of Americans said that the record heat waves last summer strengthened their belief that global warming is occurring, up 4 points since May 2011.
• 38 percent of Americans said they have personally experienced the effects of global warming, up 4 points since May of 2011.
• Americans trust “climate scientists” (74%) as a source of information about global warming more than any other group, including “other kinds of scientists” (65%) and the mainstream media (38%)

This matches September polling by ecoAmerica, which found:

• 69% of Americans Know “Weather Conditions (Such as Heat Waves and Droughts) Are Made Worse by Climate Change”
  
• 57% of Americans understand “If we don’t do something about climate change now, we can end up having our farmland turned to desert.”

That public understanding certainly matches the science:

• “Study Finds 80% Chance Russia’s 2010 July Heat Record Would Not Have Occurred Without Climate Warming”
• “NOAA Study Finds Human-Caused Climate Change Already a Major Factor in More Frequent Mediterranean Droughts”
• Study: Global warming is driving increased frequency of extreme wet or dry summer weather in southeast, so droughts and deluges are likely to get worse
• Leading experts explain how human-caused warming exacerbates Texas drought

We know from a major 2011 study that “human-induced increases in greenhouse gases have contributed to the observed intensification of heavy precipitation events found over approximately two-thirds of data-covered parts of Northern Hemisphere land areas.”

As predicted, the warming has put more water vapor in the air, making deluges more intense.  Climatologist Kevin Trenberth explains:

CLICK HERE TO READ MORE OR COMMENT

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The National Oceanic and Atmospheric Administration has released an analysis, “U.S. sets record with a dozen billion-dollar weather disasters in one year.”  They report:

• To date, the United States set a record with 12 separate billion dollar weather/climate disasters in 2011, with an aggregate damage total of approximately $52 billion. This record year breaks the previous record of nine billion-dollar weather/climate disasters in one year, which occurred in 2008.
• These twelve disasters alone resulted in the tragic loss of 646 lives, with the National Weather Service reporting over 1,000 deaths across all weather categories for the year.
• Previously only 10 events were reported; the two new billion-dollar weather and climate events added to the 2011 total include:
  • The Texas, New Mexico, Arizona wildfires event, now exceeding $1 billion, had been previously accounted for in the larger Southern Plains drought and heatwave event. This is in line with how NOAA has traditionally accounted for large wildfire events as separate events.
  • The June 18-22 Midwest/Southeast Tornadoes and Severe Weather event, which just recently exceeded the $1 billion threshold

UPDATE:  ClimateWire (subs. req’d) reported on Thursday:

… this year was not an aberration, NOAA Administrator Jane Lubchenco said during a speech here yesterday.

The seemingly endless onslaught of floods, droughts, wildfires, windstorms, blizzards and tornadoes that have marked 2011 fit within an ongoing increase in the number of natural disasters recorded in the United States, she said, citing statistics maintained by reinsurer Munich Re.

And at least some of that increase appears to be driven by climate change, Lubchenco said, citing a recent report by the Intergovernmental Panel on Climate Change.

“What we are seeing this year is not just an anomalous year, but a harbinger of things to come for at least a subset of those extreme events that we are tallying,” the NOAA chief told attendees of the American Geophysical Union’s fall meeting.

In September 2010, Munich Re one of the world’s leading reinsurers, wrote “the only plausible explanation for the rise in weather-related catastrophes is climate change.”  Here is the chart on their statistics:

CLICK HERE TO READ MORE OR COMMENT

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AP Photo/Schalk van Zuydam

by Lauren Simenauer, in a Science Progress cross-post

Delegates from 194 parties are meeting in Durban, South Africa, for the annual U.N. Conference of Parties, or COP, climate change conference. Among topics being addressed is the reduction of carbon emissions worldwide, clean energy funding in lower-income nations, and the future of the Kyoto Protocol. One lesser-discussed issue that diplomats will address is the growing body of science about the impacts of climate change on global health.

The National Resources Defense Council, or NRDC, identified six natural disaster events thought to be exacerbated by climate change. Those events include ozone air pollution, heat waves, the spread of infectious disease, river flooding, hurricanes, and wildfires. Tragically, extreme weather ravaged Durban itself just days before international delegates arrived. Torrential rains caused severe flooding that destroyed 700 homes and resulted in the deaths of 10 people. But beyond the immediate effects, all these disasters have wide-reaching consequences for national health, and a study published in Health Affairs magazine estimated that health costs incurred from the tragedies exceeded $14 billion from 2000 to 2009.

In the national debate on health care, it is imperative that the international community and our lawmakers at home not ignore the value of preventing the damage that climate change will cause to both the environment and human health.

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JR:   Here’s yet more research on how our weather is becoming more extreme and how that could lead to higher CO2 levels than expected.

Princeton researchers found for the first time that day-to-day weather conditions have become more erratic in the past generation. Days have increasingly fluctuated between sunny and dry, and cloudy and rainy with little in-between, which can have negative consequences for ecosystems, plants, solar-energy production and other factors that depend upon consistent weather.  From 1997 to 2007, rainfall became highly erratic for much of the globe, particularly in tropical areas. Green areas indicate that the day-to-day variability increased so that those areas experienced more days at one extreme or another, either dry or a downpour with little weather variation in-between.

by Morgan Kelly, Princeton University

The first climate study to focus on variations in daily weather conditions has found that day-to-day weather has grown increasingly erratic and extreme, with significant fluctuations in sunshine and rainfall affecting more than a third of the planet.

Princeton University researchers recently reported in the Journal of Climate that extremely sunny or cloudy days are more common than in the early 1980s, and that swings from thunderstorms to dry days rose considerably since the late 1990s. These swings could have consequences for ecosystem stability and the control of pests and diseases, as well as for industries such as agriculture and solar-energy production, all of which are vulnerable to inconsistent and extreme weather, the researchers noted.

The day-to-day variations also could affect what scientists can expect to see as the Earth’s climate changes, according to the researchers and other scientists familiar with the work. Constant fluctuations in severe conditions could alter how the atmosphere distributes heat and rainfall, as well as inhibit the ability of plants to remove carbon dioxide from the atmosphere, possibly leading to higher levels of the greenhouse gas than currently accounted for.

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by Jill Fitzsimmons, in a Media Matters cross-post

Last week the Intergovernmental Panel on Climate Change released a summary report on the risks posed by climate disasters. The report says climate change will likely worsen certain extreme weather events like heat waves, floods, droughts and storms.

This could be costly for the U.S., which has already experienced a record number of weather disasters this year, resulting in economic costs of almost $50 billion. The report discusses strategies for reducing vulnerability to extreme weather events.

The panel’s findings have been reported by every major print outlet in the U.S., but have been almost entirely ignored by the television news media, including CNN, Fox News, MSNBC, ABC and CBS. The only mention of the U.N. report on a major TV news outlet was a segment on NBC Nightly News.

This is not the first time television networks have made time for stories that are less than newsworthy, but not for important developments in climate change science.

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A USA Today (not IPCC) chart emphasizes the risk of drought in heavily populated areas.

The IPCC Special Report “Managing the Risks of Extreme Events and Disasters to Advance Climate Change Adaptation (SREX)” is now online.  I had seen the previous draft and the changes to it, so I knew that it was a big missed opportunity, as I explained here.

UPDATE:  Dr. Richard Klein offers a defense of the IPCC process in the comments of my previous post (here).

Even so, since the media hasn’t been spending much time connecting the dots between extreme weather and climate change, the report has garnered some headlines:

• Report: Climate change worsens extreme weather events (USA Today)
• Extreme weather to worsen with climate change: IPCC (Reuters)
• Extreme weather will strike as climate change takes hold, IPCC warns; Heavier rainfall, storms and droughts could wipe billions off economies and destroy lives, says report by 220 scientists (UK Guardian).

There is definitely some good material in the report (I’ll do a separate post on that).  We should all appreciate the hard work that a great many scientists put into this report.  I’ve been highly supportive of IPCC scientists over the years, pushing back against the attacks by the deniers and confusionists — even as I have been critical of the IPCC process that tends to water down even the most obvious conclusions.

For instance, the report states:

It is virtually certain that increases in the frequency and magnitude of warm daily temperature extremes and decreases in cold extremes will occur in the 21st century on the global scale. It is very likely that the length, frequency and/or intensity of warm spells, or heat waves, will increase over most land areas.

Virtually certain means “99-100% probability” while very likely means “90-100% probability.”  Is there really as much as a 10% chance that the length, frequency and/or intensity of warm spells, or heat waves, will NOT increase over most land areas over the next 90 years?

Then we have this line:

It is very likely that mean sea level rise will contribute to upward trends in extreme coastal high water levels in the future.

C’mon guys and gals.  You couldn’t put a “virtually certain” on that?  Note that the sentence is already hedged with “will contribute” and “upward trends” and even the vague “in the future.”  Precisely how could mean sea level rise — even sticking with the lowball estimate from the 2007 report — have as much as a 10% chance of NOT contributing toward an upwards trend in extreme coastal high level waters sometime in the future.

So you can see the effect of the IPCC process that waters down even the most innocuous conclusions.  And by the way, since this is a 2011 report, it ought to base such statements on the recent literature of sea level rise, which is considerably higher than the 2007 estimate (see the discussion in “Scientists withdraw low-ball estimate of sea level rise“).

My biggest problem with the report remains the short shrift it gives to the vast literature on drought that I reviewed in my recent Nature article.  As I wrote, “Feeding some 9 billion people by mid-century in the face of a rapidly worsening climate may well be the greatest challenge the human race has ever faced.”

You can see from the chart above that USA Today (and Jeff Masters, who helped put it together) figured out that drought may be the biggest extreme weather danger in that it affects 5 heavily populated areas.

Reuters, in its story, states what should be obvious:

Droughts, perhaps the biggest worry for a world with a surging population to feed, were also expected to worsen.

The 29-page report itself has quite little on droughts, and the word “agriculture” appears only once in the main text, but it does have this blockbuster chart:

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