Archive for the ‘flood’ Category

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Los Angeles underwater

March 24, 2011

There is good news and bad news coming out of California.  The bad news is that the Chicken Littles are clucking about sea level rise.  The good news is that at least some coastal communities are acting sensibly instead of panicking.

The Bad News

We live in trying times.  As our greatest minds peer into the future through their climate models we are only now beginning to understand the appalling fate that awaits us in an overheated, over-carbonized world.  Los Angeles is the latest city to be warned of its frightful destiny.

According to the Los Angeles Times

Sea levels have risen about 8 inches in the last century, and scientists expect them to rise several feet by the end of this century as climate change warms the ocean.

The hardest hit area of Los Angeles would be the Harbor/San Pedro/Long Beach region. As the LA Times notes, global seas rose by about 8 inches during the last century. Let’s see what impact this rise has had along the Harbor area of Los Angeles.  The following animation was made from a detail of a 1912 T. Newman map of Los Angeles county and from a 2011 Google Earth image.  The top half is photoshopped to clearly demarcate the land and water.

I can just hear the Chicken Littles clucking “Sure, the Los Angeles harbor region gained ground during the 20th century.  But that was with only 8 inches of sea level rise.  And everybody knows that the sea level rise rate along the california coast is rapidly increasing due to global warming.” 

Not so fast, Mr Little.  Here is the relative sea level at Los Angeles for the last 85 years from the National Oceanic and Atmospheric Administration (NOAA).  Click to see the graph in context at the NOAA website.

Wait a minute, only 0.83 mm per year?  That’s only 83 mm (or 3.5 inches) per century.  And there is no acceleration that I can see.  It is kind of hard to believe there will be “several feet by the end of this century.” 

What would be the consequences of “several feet [of sea level rise] by the end of this century?”  The bad news for Los Angeles and California was first revealed in the Pacific Institute’s  “The Impacts of Sea-Level Rise on the California Coast.”    They considered the devastation that will be wrought by a 1.4 meter (4.6 feet) sea level rise (based on the seminal work of Stefan Rahmstorf) during the 21st century.

The Pacific Institute created Hazard Maps of sections of  the California coast that would be inundated by a 100 year flood event with sea levels at their current level and with sea levels 1.4 meters higher.  I have stitched together several of those maps to show the region from the Los Angeles Harbor over to the Seal Beach area.  The light blue areas show the places that the Pacific institute figures would be inundated in a 100 year flood with year 2000 sea levels.  The dark blue areas show the places that they think would be flooded with the same 100 year event and an additional 1.4 meters of sea level.

But with the present, nearly steady, sea level rise rate the sea level will only go up by 0.083 meters (about 3.5 inches)  in 100 years.  Roughly speaking, if there is no acceleration in sea level rise rate near Los Angeles, then only about 6% of the dark blue areas would actually flood.

Sea level rise rates would have to increase unrealistically to get to an extras 1.4 meters in the 21st century.  We are 10 years into the century so far, and the sea level near Los Angeles has gone up only about 8 millimeters.  That leaves 1,392 millimeters to go in the next 90 years.  Here are a few hypothetical of sea level rise rate scenarios for the 21st century that would get us those 1392 millimeters…


These scenarios don’t look very promising, do they?  If we could somehow increase the sea level rise rate in Los Angeles harbor from its present value of 0.83 milimeters per year up to about 15 mm/year (a minor 18 fold increase) overnight, and keep it there for the next 90 years we could reach that target of 1.4 meters of sea level rise for the century.  Or we could try a linearly increasing sea level rise rate that gets to about 30 mm/year  by 2100.  That’s a whopping 36 fold increase from today’s rate by 2100. 

Here’s the deal:  The sea level at Los Angeles has an acceleration 0.0019 mm/year/year.  Unless there is a gigantic increase in that rise rate, then the seas will rise by only about 12 cm in this century.  And there is zero indication that the sea level rise rate in Los Angeles has increased a whit in the last 85 years.

The good news

Although the Los Angeles Times article tries to impart a notion of acquiesence to the sea level rise scare by the “conservative city” of Newport Beach, they go on to say…

“…city planners are looking at raising seawalls by a foot or more to hold back the ocean.”

Wow, a whole one foot to protect from 1.4 meters (4.5 feet) of sea level rise.  Seems like the city planners in Newport Beach agree with my assesment more than with the 1.4 meter scare predicted by Mr. Rahmstorf.

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Manhattan underwater

August 21, 2010

Heide Cullen has written a new book expressing her views about the world’s climate 40 years from now.   You may recall that Cullen is the Weather Channel climatologist who suggested that other meteorologists and climatologists who express doubts about anthropogenic global warming be decertified by the American Meteorological Society

Her new book, “The Weather of the Future,” features an alarming computer generated image of Manhattan in a sea-level-risen, hurricane plagued world of 2050 on the front cover. 

 

In the world of digital graphics you can create any reality you desire.  In this case Cullen presents Manhattan underwater, presumably after 40 years of sea level rise combined with a category 4 hurricane storm surge.   

The following picture is a close-up detail of the buildings.  The group of buildings in the foreground is Lower Manhattan and the group of buildings in the background is Midtown Manhattan.  “The Village” area, Chelsea, the Garment district, etc., between Lower and Midtown Manhattan is conspicuously covered in water.  Water surrounds the Empire State Building, and 250 foot tall buildings immediately south of it are submerged. 


The following picture is from Google Earth with a photorealistic rendering of the buildings on Manhattan as it would look today.  Again, you can see the skyscrapers of Lower and Midtown Manhattan.  Battery Park is the green area at the tip of Lower Manhattan.  You can also see the thousands of buildings in the region between Lower and Midtown Manhattan. 


What would it take to cover The Village, Chelsea and the Garment District in water?

Land on Manhattan is obviously very valuable, and the only way to expand is to go vertical.  The region between Lower and Midtown Manhattan is not covered with thatched roofed tiki huts that will wash away in a hurricane.  There are thousands of multi-story buildings, many of which are a hundreds of feet tall.  The following Google Earth photorealistic rendering is of a typical location in the Village area (in this case near the corner of Allen St. and E. Houston St.) looking back toward Lower Manhattan.  The labels show the elevations above sea level of the roofs of several buildings. 

 

For all of these buildings to disappear below the water the combined hurricane storm surge and sea level rise would have to be over a whopping 250 feet! 

Hurricanes have hit New York before and their potential effects are not a mystery.  Some of them have been pretty devastating.  You can see the New York and Long Island areas that would be under water today for category 1 through 4 storms hitting at high tide here.  The image below shows a close up of the storm surge coverage of Manhattan with the green shaded areas covered with water for a category 4 storm.  The deepest water might be about 25 feet above sea level. 

 

Cullen’s book shows the Empire State Building on the high ground of  Midtown Manhattan surrounded by water.  The reality is that only the very edges of Midtown Manhattan would go under water. Much of the low-lying ground of the Village area would be underwater, but unlike Cullen’s book cover, virtually every building would still tower above the water.  The streets at the base of the Empire State Building would be far above the storm surge floods. 

Of course, if the sea level rises due to global warming, then the hurricane storm surge would be even worse.  So, according to Cullen, how much will the sea level rise by 2050?  On page 258 she says… 

The new estimates for 2050, once you included all the sources of the rise in sea level – from Greenland, from Antarctica, from glaciers and ice caps, and from thermal expansion – as well as the dynamic effects, could be as high as 3 feet.  

So, according to Cullen, you can add three more feet to the storm surge.  That ought to cover those buildings. 

How realistic is three feet of sea level rise?

But even Cullen’s 3 foot sea level rise in the next 40 years for Manhattan is rather far-fetched.  There is a century and a half of sea level data for The Battery at the tip of Lower Manhattan.  Take a look… 

 

That’s it: 2.77 mm (about a tenth of an inch) per year for the last 150 years.  No acceleration of the sea-level-rise-rate has accompanied increasing atmospheric CO2 levels.   To get three feet in the next 40 years the sea level must rise an average of about 23 mm per year between now and 2050.  That is a sea-level-rise-rate increase by a factor of nine.  Something like this… 


Giving credit where credit is due

Manhattan gets off more easily in Cullen’s Weather of the Future than it does in many other disaster stories.  Consider The Day After Tomorrow, where Manhattan gets both flooded and frozen, or the fate of New York in Planet of the Apes.  In Weather of the Future Manhattan’s problems are successfully managed by civil engineers and good planning.  At least we can be grateful for that momentary break from the usual global warming narrative. 

The Day After Tomorrow

Planet of the Apes

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Climate change in North Dakota

April 7, 2009
This post is in response to Darin, who left a good comment on my previous post concerning flooding in North Dakota.  Darin said:

Something is going on. I have lived here all my life and experienced two of the record level floods prior to the 1997 flood. That was the flood of 1975 and 1979.

Since then we’ve had 97-2001-2006-2009 that have each bumped all other years in the previous 110 years of record keeping down the list.

Now 7 of the top 10 flood levels come in the last 25 years.

You don’t have to have a masters in statistics to see a correlation to SOMETHING? I don’t know if it is global warming changing weather patterns, but they are changing.

Darin’s observations are legitimate and he has asked some good questions.  I would say that perhaps a master’s in statistics would, in fact, be useful in this situation.  But references to paleoclimatological records would be even more useful.  Why?  Because the real question is whether or not the climate in North Dakota and surrounding areas in the last several decades (while CO2 levels have gone up significantly) has varied in an obvious way from the magnitude of fluctuations seen during the “normal times” over the last several millennia (before CO2 levels rose).   

Consider recent history first. 

Pre-industrial CO2 levels are typically pegged at 280 ppm (parts per million).    Levels rose slowly during the 19th century and reached about 290 ppm by around 1930 and 310 ppm around 1950.   Today the number is at about 385 ppm, as shown below.  So I think that we can agree that the CO2 level started rapidly increasing when the world started becoming highly industrialized in the 40s and 50s. 

mauna-loa-co2

So when did the most extreme measured temperatures occur in North Dakota?  Answer: in the 1930s (-60 and +121 degrees F), when CO2 levels were much closer the pre-industrial levels.  When was the previous measured record crest of the Red River?  Answer: 1897, at 40.1 feet, when atmospheric CO2 levels were almost at pre-industrial  levels.

Paleoclimatological history

Drought is the most commonly sited risk of CO2 induced anthropogenic global warming for North Dakota.  For example, the Center for Integrative Environmental Research at the University of Maryland reports in their paper “Economic Impacts of Climate Change on North Dakota”:

“Atmospheric models predict that North Dakota will become drier in the future, with drought patterns becoming more intense as a consequence of global warming.”

Additionally the argument is made that rising levels of atmospheric CO2 will result in “climate change,” as opposed simple “global warming,” with greater extremes in temperature, precipitation, etc.  Using this terminology any changing climate conditions can be attributed to anthropogenic CO2, right?  Well, no.  This argument only works if it can be shown that the range of weather extremes in the era of increasing CO2 is statistically greater than the range of weather extremes during at least several thousand years while CO2 held steady at about 280 ppm.   What does the paleoclimatological record say about North Dakota climate for the last several thousand years?

In 1999, in the Proceedings of the North Dakota Academy of Sciences, Allan Ashworth pointed out that:

North Dakotan’s know only too well the effects of climate change. From 1988 to 1992 the State experienced drought conditions but since then North Dakota has been in a wet cycle. North Dakotans are stoical when it comes to weather but even so there is a concern about what the future will bring. Most of our knowledge of climate change comes from an instrumental record that is only 100 years in length. This record has been extended by dendroclimatology and by high resolution paleontologic and geochemical studies of lake sediments. What these studies are showing is that 100 years is far to short a time to show the variability in the climate record. (emphasis added)
 

 Ashworth points out some interesting details.  For example, at Rice Lake “maximum drought conditions during the mid-Holocene occurred between 7-6” thousand years ago.  Similarly, “maximum drought conditions at Elk Lake, Itasca Park, Minnesota, occurred between 6.2 to 6” thousand years ago.  At Moon Lake the presence of Iva pollen (which at the present “does not extend north of Nebraska…is thought to represent warmer conditions”  in the mid-Holocene.  Ashworth gives details of lake salinity and level changes during the mid-Holocene and notes “The general assumption is that significant changes in the lake levels are the result of climate change” during the last several thousand years, before CO2 levels rose.  He further notes:

“Individual records show a lot of variation, but there appears to be a cyclicity to drought, with intense droughts occurring on a frequency of 40 – 60 years. What is particularly striking is the Moon Lake salinity record is the magnitude of a series of droughts prior to AD 1200: at AD 200-370, AD 700-850 and AD 1000 -1200. These droughts were all of a greater magnitude than the intense drought of the 1930’s.”

In a 1997 Quaternary Research paper concerning climate variability, as measured by a variety of markers at Moon Lake, North Dakota,  Blas L. Valero-Garces, et al. wrote:

Seismic stratigraphy, sedimentary facies, pollen stratigraphy, diatom-inferred salinity, stable isotope (δ18O and δ13C), and chemical composition (Sr/Ca and Mg/Ca) of authigeniccarbonates from Moon Lake cores provide a congruent Holocene record of effective moisture for the eastern Northern Great Plains. … A change at about 710014C yr B.P. inaugurated the most arid period during the Holocene. Between 7100 and 400014C yr B.P., three arid phases occurred at 6600–620014C yr B.P., 5400–520014C yr B.P., and 4800–460014C yr B.P. Effective moisture generally increased after 400014C yr B.P., but periods of low effective moisture occurred between 2900–280014C yr B.P. and 1200–80014C yr B.P. The data also suggest high climatic variability during the last few centuries.  (emphasis added)

 If Valero-Garces, et. al., are correct then is seems that recent variability in North Dakota is not unusual, and cannot be blamed on anthropogenic CO2.

Sherilyn C. Fritz of the University of Nebraska – Lincoln Department of Geosciences and her co-authors considered the “Hydrologic Variation in the Northern Great Plains During the Last Two Millennia“, and claim that

“The data show that the last 2,000 years have been characterized by frequent shifts between high and low salinity, suggesting shifts between dry and moist periods. Long intervals of high salinity suggest periods of multiple decades when droughts were intense and frequent, thus indicating times when drought was more persistent than in the 20th century. ..[T]he climate of the last 2000 years was hydrologically complex, with large oscillations between low-salinity wet phases and high-salinity dry phases.” (emphasis added)

Fritz gives details from three North Dakota lake sites showing constant variation…

“All records show an interval of prolonged drought between ca. A.D. 40 and 130, followed by a wetter period, and also a dry period about A.D. 250, which two of the records (Moon [Lake]and Rice [Lake]) suggest was sustained for more than a century. Shorter periods of drought are evident at ca. A.D. 400 and 530, and the data suggest a period of major and sustained drought from ca. A.D. 620 to 790. The time from A.D. 1020 to 1150 was also characterized by major drought and was followed by a distinct wet interval to at least A.D. 1300. …. All sites show intervals of very fresh conditions, suggesting high precipitation, sometime between A.D. 1330 and 1430 and in the early decades of the 1800s. The data also suggest periods of drought in the decades surrounding A.D. 1500, 1600, and 1800, and in the latter decades of the 19th century.”

Kathleen Laird of the Department of Ecology at the University of Minnesota writes in Nature  that

“Extreme large-scale droughts in North America, such as the “Dust Bowl” of the 1930s, have been infrequent events within the documented history of the past few hundred years, yet this record may not be representative of long-term patterns of natural variation of drought intensity and frequency. .. Here we present a reconstruction of drought intensity and  frequency over the past 2,300 years in the Northern Great Plains…” (emphasis added)

Laird studied the salinity record of Moon Lake, North Dakota, as an indicator changing hydrological conditions and said…

“Our working assumption is that periods of positive water balance (precipitation > evapotranspiration) are reflected by higher lake levels and lower salinities, whereas when the water balance is negative, lake levels are lower and salinity higher …”

and found the following fluctuating signal:

Figure 2.  Salinity of Moon Lake, North Dakota, from Laird, et. al., Nature

Figure 2. Salinity of Moon Lake, North Dakota, from Laird, et. al., Nature

My conclusion is that the precipitation variation seen over the last 100 years in North Dakota is not unusual when compared to previous centuries, when CO2 levels remained near 280 ppm