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Tag Archive: extreme

  1. Ancient Egypt’s rulers mishandled climate and natural disasters. Then the people revolted.

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    by William Wan October 17, 2017 read full Washington Post article here

    The leaders of ancient Egypt knew a thing or two about natural disasters. Handle a famine or drought badly as pharaoh, and you could have empire-wide revolt on your hands.

    A new study shows how big a role climate change and natural disasters likely played in sparking such political uprisings. And it suggests that despite frequent famines, the Egyptian rulers failed to grasp just how vulnerable they were to environmental devastation right up until the day their empire collapsed. It is a lesson contemporary leaders may find both instructive and alarming as they increasingly cope with one freakish weather event after another….

    The study — published Tuesday in the journal Nature Communications — combines ice core dating of ancient volcanic eruptions with papyrus records of uprisings to show that each time there was a volcanic eruption during Egypt’s Ptolemaic period, it led almost inevitably to unhappiness and revolt….

    …Manning, co-author of Tuesday’s study, said he sees another historical lesson in the fall of Cleopatra and the Ptolemaic Empire. “For so long, they had been playing so close to the edge, fighting huge wars and growing crops that were especially vulnerable to changes in the Nile. They refused to change their politics and it left them vulnerable once larger forces in nature and in the world came along and pushed them over the edge.”

  2. ‘Horizontal hurricanes’ – atmospheric rivers pose extreme storm risk but also drought-busting opportunity for California; plans for new 2-3 week forecast and ranking system similar to hurricanes

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    • Severe atmospheric rivers in California could mean 23 days of rain and wind  causing floods and landslides to the tune of $300 billion in property damage per past USGS modeling
    • Atmopheric rivers — while carrying the potential for more damage — will also help California maintain typical rainfall levels amid a drying climate.
    • plan to begin publishing regular 14-day to 21-day outlooks on atmospheric rivers as soon as this winter along with new rating system for intensity on a scale of 1 to 5, similar to hurricanes.

    By Kurtis Alexander September 27, 2017 read full SF Chronicle article here

    …California is facing its own threat of bigger and more destructive storms. Mounting research, much of it done in the wake of the near-record rains that pulled California out of a five-year drought this past winter, shows that seasonal soakers may not come as often as they used to, but could pack more punch when they do arrive.

    ….The massive weather systems that rise out of the Pacific Ocean, now popularly called atmospheric rivers, can drop as much water as Hurricane Irma dumped on Florida this month — billions of gallons that submerged cities and towns.

    …U.S. Geological Survey ran a simulation of what a sequence of severe atmospheric rivers might look like in California…. 23 days of rain and wind that caused floods and landslides to the tune of $300 billion in property damage….big drenchers earlier this year…caused mass flooding in San Jose and other cities and triggered a near-catastrophe at Lake Oroville when a pair of dam spillways failed.

    …A group of Southern California scientists, some of whom are partnering with Sonoma County, plan to begin publishing regular 14-day to 21-day outlooks on atmospheric rivers as soon as this winter. Current forecasts typically don’t anticipate the events more than a week out.

    …Marty Ralph, director of the Center for Western Weather and Water Extremes at UC San Diego’s Scripps Institution of Oceanography, is also working to develop a rating system for the storms.  The blasts will be evaluated for intensity on a scale of 1 to 5, similar to hurricanes. A test run of the ratings last winter pegged the strong atmospheric river in February, which contributed to the damage at Oroville Dam, as a category 5 eventResearch published in the journal Geophysical Research Letters in August, which Ralph participated in, indicates that atmospheric rivers are carrying increasing amounts of water.

    …Sometimes called horizontal hurricanes, atmospheric rivers are exactly what they sound like: airborne channels of water that develop over the Pacific Ocean and are pushed along by strong winds toward the West Coast during the winter….providing as much as 50 percent of the state’s annual rainfall in a matter of days — dumpings that are critical to water supplies but, at times, bring on disaster…

    Another study [published in September] in the journal Scientific Reports, suggests that the swelling intensity of atmospheric rivers — while carrying the potential for more damage — will also help California maintain typical rainfall levels amid a drying climate….

    During the height of the drought, California went as long as a year without seeing a single atmospheric river. But the state was hit by more than 30 of the systems last winter, according to Scripps researchers. That explains why the season was one of the wettest on record….

    Alexander Gershunov, Tamara Shulgina, F. Martin Ralph, David A. Lavers, Jonathan J. Rutz. Assessing the climate-scale variability of atmospheric rivers affecting western North America. Geophysical Research Letters. Volume 44, Issue 15 16 August 2017. Pages 7900–7908 DOI: 10.1002/2017GL074175

  3. Extreme precipitation frequency in CA expected to increase but decrease in other Mediterranean climate regions

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    • Frequencies of extreme precipitation are projected to increase over Northern Hemisphere- especially Califormia- where projected warming is strongest.
    • California’s more nuanced hydrological future reflects a precarious balance between the expanding subtropical high from the south and the south-eastward extending Aleutian low from the north-west– bolstering more extreme precipitation events.
    • More drought expected over Mediterranean basin due to decreased winter precipitation.

    Suraj D. Polade, Alexander Gershunov, Daniel R. Cayan, Michael D. Dettinger & David W. Pierce. Precipitation in a warming world: Assessing projected hydro-climate changes in California and other Mediterranean climate regions. Scientific Reports 7, Article number: 10783 (2017) doi:10.1038/s41598-017-11285-y

    ABSTRACT: In most Mediterranean climate (MedClim) regions around the world, global climate models (GCMs) consistently project drier futures. In California, however, projections of changes in annual precipitation are inconsistent. Analysis of daily precipitation in 30 GCMs reveals patterns in projected hydrometeorology over each of the five MedClm regions globally and helps disentangle their causes. MedClim regions, except California, are expected to dry via decreased frequency of winter precipitation. Frequencies of extreme precipitation, however, are projected to increase over the two MedClim regions of the Northern Hemisphere where projected warming is strongest. The increase in heavy and extreme precipitation is particularly robust over California, where it is only partially offset by projected decreases in low-medium intensity precipitation. Over the Mediterranean Basin, however, losses from decreasing frequency of low-medium-intensity precipitation are projected to dominate gains from intensifying projected extreme precipitation. MedClim regions are projected to become more sub-tropical, i.e. made dryer via pole-ward expanding subtropical subsidence. California’s more nuanced hydrological future reflects a precarious balance between the expanding subtropical high from the south and the south-eastward extending Aleutian low from the north-west. These dynamical mechanisms and thermodynamic moistening of the warming atmosphere result in increased horizontal water vapor transport, bolstering extreme precipitation events.

  4. Rethinking Infrastructure and Resilience Amid a Blitz of Hurricanes

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  5. Extreme weather has limited effect on attitudes toward climate policies

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    September 7, 2017 Indiana University  read full ScienceDaily article here

    People who recently experienced severe weather events such as floods, storms and drought are more likely to support policies to adapt to the effects of climate change, according to a new study co-authored by an Indiana University researcher. But the relationship between exposure to extreme weather and support for climate policies is small, the study finds. And it fades quickly; a month after an extreme weather event, there was no effect….

    …The researchers examined survey responses from the Cooperative Congressional Election Study and correlated them with data from the National Weather Service’s Storm Events Database. They focused on three policies for climate adaptation: restrictions on coastal development, limits on outdoor residential water use and regulation of stormwater runoff from residential property.

    All three policies enjoyed considerable support, but respondents who had experienced recent extreme weather expressed only modestly stronger support than other respondents.

    Aaron Ray, Llewelyn Hughes, David M. Konisky, Charles Kaylor. Extreme weather exposure and support for climate change adaptation. Global Environmental Change, 2017; 46: 104 DOI: 10.1016/j.gloenvcha.2017.07.002

  6. As Hurricane Harvey hits Gulf Coast, Central Valley must prepare for the coming storm- Editorial

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    • The Big One in the form of a superstorm may come this winter, or the next or the one after that. But it is headed this way.
    • New plan calls for multi-benefit floodplain management, expanding bypasses and limiting building
    • Giving rivers and floodways more room to carry flood waters is the best way to protect communities from dangerous floods, and giving rivers more room provides multiple benefits, including clean water, parks, and habitat for fish and wildlife.
  7. Harvey Is What Climate Change Looks Like

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    • It’s time to open our eyes and prepare for the world that’s coming.
    • Harvey is the third 500-year flood to hit the Houston area in the past three years, but Harvey is in a class by itself. By the time the storm leaves the region on Wednesday, an estimated 40 to 60 inches of rain will have fallen on parts of Houston. So much rain has fallen already that the National Weather Service had to add additional colors to its maps to account for the extreme totals.
    • Harvey is a storm decades in the making.
    • Insisting on a world that doesn’t knowingly condemn entire cities to a watery, terrifying future isn’t “politicizing” a tragedy—it’s our moral duty.
    • The symbolism of the worst flooding disaster in U.S. history hitting the sprawled-out capital city of America’s oil industry is likely not lost on many. Institutionalized climate denial in our political system and climate denial by inaction by the rest of us have real consequences. They look like Houston.

    By ERIC HOLTHAUS

    In all of U.S. history, there’s never been a storm like Hurricane Harvey. That fact is increasingly clear, even though the rains are still falling and the water levels in Houston are still rising.

    But there’s an uncomfortable point that, so far, everyone is skating around: We knew this would happen, decades ago. We knew this would happen, and we didn’t care. Now is the time to say it as loudly as possible: Harvey is what climate change looks like. More specifically, Harvey is what climate change looks like in a world that has decided, over and over, that it doesn’t want to take climate change seriously.

    Houston has been sprawling out into the swamp for decades, largely unplanned and unzoned. Now, all that pavement has transformed the bayous into surging torrents and shunted Harvey’s floodwaters toward homes and businesses. Individually, each of these subdivisions or strip malls might have seemed like a good idea at the time, but in aggregate, they’ve converted the metro area into a flood factory. Houston, as it was before Harvey, will never be the same again.

    …Climate change is making rainstorms everywhere worse, but particularly on the Gulf Coast. Since the 1950s, Houston has seen a 167 percent increase in the frequency of the most intense downpours. Climate scientist Kevin Trenberth thinks that as much as 30 percent of the rainfall from Harvey is attributable to human-caused global warming. That means Harvey is a storm decades in the making….

    ….The symbolism of the worst flooding disaster in U.S. history hitting the sprawled-out capital city of America’s oil industry is likely not lost on many. Institutionalized climate denial in our political system and climate denial by inaction by the rest of us have real consequences. They look like Houston.

    Once Harvey’s floodwaters recede, the process will begin to imagine a New Houston, and that city will inevitably endure future mega-rainstorms as the world warms. The rebuilding process provides an opportunity to chart a new path. The choice isn’t between left and right, or denier and believer. The choice is between success and failure.

  8. Four things Houston-area leaders must do to prevent future flooding disasters

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    Read full article in the Texas Tribune

    …This may seem like a freak occurrence. But it’s the third catastrophic flooding event this region of 6.5 million people has experienced in three years. And scientists and other experts say that much of the devastation could have been prevented. …They say local officials need to account for more frequent and intense rains that are sure to come with climate change, rather than looking to what has happened in the past in their search for solutions.

    Here’s what local leaders could have done to protect the region — and what they must do to prevent such disasters in the future.

    Preserve and restore as much prairie land as possible

    Much of northwest Houston used to be covered in prairie land, where tall grasses could absorb huge amounts of floodwater….

    Restrict development in floodplains and buy flood-prone homes

    Buildings continue to go up in vulnerable floodplains all over Harris County. A few years ago the city of Houston tried to ban new development in the most flood-prone areas. …

    Plan for climate change

    In planning for flooding from future storms, local officials largely look to past rainfall totals and weather patterns. But climate change will heighten the risks that the region already faces. That’s particularly true because it sits so close to the Gulf of Mexico, where sea levels are rising and waters have been warming as the planet gets hotter….“The exact same storm that comes along today has more rain associated with it than it would have 50 or 100 years ago,” renowned climate scientist Katharine Hayhoe told The Texas Tribune last year. Hayhoe said Houston needs to plan for more frequent and intense rainstorms, just like many other cities in the country….

    Educate the public

    Hundreds of thousands of people have moved to the Houston area in recent decades; it’s consistently ranked as one of the nation’s fastest-growing cities. But people who move to flood-prone areas are often unaware of the risks….

  9. Houston’s Flood Is a Design Problem

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    • It’s not because the water comes in. It’s because it is forced to leave again.
    • Reducing impervious surfaces and improving water conveyance has a role to play
    • most important step is to reduce the velocity of water when it is channelized, so that it doesn’t deluge other sites. And then to stop moving water away from buildings and structures entirely, and to start finding new uses for it in place.
    • China’s “sponge cities” as a dramatic example—a government-funded effort to engineer new, permeable materials to anticipate and mitigate the flooding common to that nation….

    Ian Bogost  The Atlantic  August 29 2017  Read full article here

    …But the impact of flooding, particularly in densely developed areas like cities, is far more constant than a massive, natural disaster like Harvey exposes. The reason cities flood isn’t because the water comes in, not exactly. It’s because the pavement of civilization forces the water to get back out again.

    Under normal circumstances, rain or snowfall soaks back into the earth after falling. It gets absorbed by grasslands, by parks, by residential lawns, by anywhere the soil is exposed. Two factors can impede that absorption. One is large quantities of rain in a short period of time. The ground becomes inundated, and the water spreads out in accordance with the topography. The second is covering over the ground so it cannot soak up water in the first place. And that’s exactly what cities do—they transform the land into developed civilization.

    Roads, parking lots, sidewalks, and other pavements, along with asphalt, concrete, brick, stone, and other building materials, combine to create impervious surfaces that resist the natural absorption of water. In most of the United States, about 75 percent of its land area, less than 1 percent of the land is hardscape. In cities, up to 40 percent is impervious….

    …In Houston’s case, catastrophic floods have been anticipated for some time. The combination of climate change, which produces more intense and unpredictable storms, and aggressive development made an event like this week’s almost inevitable. The Association of State Floodplain Managers has called for a national flood risk-management strategy, and the Houston Chronicle has called flood control the city’s “most pressing infrastructure need.” …

    …Houston poses both a typical and an unusual situation for stormwater management. The city is enormous, stretching out over 600 square miles. It’s an epitome of the urban sprawl characterized by American exurbanism, where available land made development easy at the edges. Unlike New Orleans, Houston is well above sea level, so flooding risk from storm surge inundation is low. Instead, it’s rainfall that poses the biggest threat.

    A series of slow-moving rivers, called bayous, provide natural drainage for the area. To account for the certainty of flooding, Houston has built drainage channels, sewers, outfalls, on- and off-road ditches, and detention ponds to hold or move water away from local areas. When they fill, the roadways provide overrun. The dramatic images from Houston that show wide, interstate freeways transformed into rivers look like the cause of the disaster, but they are also its solution, if not an ideal one. This is also why evacuating Houston, a metropolitan area of 6.5 million people, would have been a terrible idea. This is a city run by cars, and sending its residents to sit in gridlock on the thoroughfares and freeways designed to become rivers during flooding would have doomed them to death by water.

    Accounting for a 100-year, 500-year, or “million-year” flood, as some are calling Harvey’s aftermath, is difficult and costly. Stiftel confirms that it’s almost impossible to design for these “maximal probable flood events,” as planners call them. Instead, the hope is to design communities such that when they flood, they can withstand the ill effects and support effective evacuations to keep people safe. “The Houston event seems like an illustration that we haven’t figured it out,” Stiftel says.

    Many planners contend that impervious surface itself is the problem. The more of it there is, the less absorption takes place and the more runoff has to be managed. Reducing development, then, is one of the best ways to manage urban flooding. The problem is, urban development hasn’t slowed in the last half-century. Cities have only become more desirable, spreading outward over the plentiful land available in the United States….

    ….In other cases, floodplains have been managed through redevelopment that reduces impervious surfaces. Natural ground cover, permeable or semi-permeable pavers, and vegetation that supports the movement of water offer examples. These efforts dovetail with urban redevelopment efforts that privilege mixed-use and green space, associated with both new urbanism and gentrification. Recreation lands, conservation lands and easements, dry washes, and other approaches attempt to counterbalance pavement when possible. Stiftel cites China’s “sponge cities” as a dramatic example—a government-funded effort to engineer new, permeable materials to anticipate and mitigate the flooding common to that nation….

    ….Reducing impervious surface and improving water conveyance has a role to play, but the most important step in sparing cities from flooding is to reduce the velocity of water when it is channelized, so that it doesn’t deluge other sites. And then to stop moving water away from buildings and structures entirely, and to start finding new uses for it in place.

    That can be done by collecting water into cisterns for processing and reuse—in some cases, Debo explains, the result can even save money by reducing the need to rely on utility-provided water. Adding vegetation, reclaiming stormwater, and building local conveyance systems for delivery of this water offer more promising solutions….

    ….Instead of looking for holistic answers, site-specific ones must be pursued instead. Rather than putting a straight channel through a subdivision, for example, Debo suggests designing one to meander through it, to decrease the velocity of the water as it exits

    …But there are some regions that just shouldn’t become cities. “Parts of Houston in the floodway, parts of New Orleans submerged during Katrina, parts of Florida—these places never should have been developed in the first place,” Debo concludes. Add sea-level rise and climate-change superstorms, and something has to give.

    …Residential homeowners who install a new cement patio or driveway might not even realize that they are channeling water down-grade to their neighbors, or overwhelming a local storm drain. Citizens can also influence stormwater issues within their municipalities. Many folks know that they have a local city council and school board, but local planning, zoning, and urban design agencies also hold regular public meetings—unfortunately, most people only participate in this aspect of local governance when they have an axe to grind. For the average American concerned with the deluge, the best answer is to replace an occasional, morbid curiosity with flooding with a more sophisticated, long-term interest in stormwater management.

  10. Human-caused warming likely led to recent streak of record-breaking temperatures globally

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    • It is “extremely unlikely” 2014, 2015 and 2016 would have been the warmest consecutive years on record without the influence of human-caused climate change, according to the authors of a new study.

    August 10, 2017 American Geophysical Union  Read full ScienceDaily article here

    ….Temperature records were first broken in 2014, when that year became the hottest year since global temperature records began in 1880. These temperatures were then surpassed in 2015 and 2016, making last year the hottest year ever recorded. In 2016, the average global temperature across land and ocean surface areas was 0.94 degrees Celsius (1.69 degrees Fahrenheit) above the 20th century average of 13.9 degrees Celsius (57.0 degrees Fahrenheit), according to NOAA.

    Combining historical temperature data and state-of-the-art climate model simulations, the new study finds the likelihood of experiencing consecutive record-breaking global temperatures from 2014 to 2016 without the effects of human-caused climate change is no greater than 0.03 percent and the likelihood of three consecutive record-breaking years happening any time since 2000 is no more than 0.7 percent.

    When anthropogenic warming is considered, the likelihood of three consecutive record-breaking years happening any time since 2000 rises to as high as 50 percent, according to the new study…

    Michael E. Mann, Sonya K. Miller, Stefan Rahmstorf, Byron A. Steinman, Martin Tingley. Record Temperature Streak Bears Anthropogenic Fingerprint. Geophysical Research Letters, 2017; DOI: 10.1002/2017GL074056