Manhattan underwater

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

The Thermohaline Circulation Only Stops for Extreme, Unrealistic Models

Return to Criticisms of Al Gore’s “An Inconvenient Truth”

Gore gives a cartoon description of the ocean circulation system when he explains what has become known as the thermohaline circulation, or the meridional overturning circulation.  In his simplistic scenario the surface ocean current that flows north in the Atlantic, bringing warmth to northern Europe will be halted by melting ice from Greenland, subsequently throwing Europe into an ice age. 

Here is Gore’s explanation in his own words from the Inconvenient Truth movie:

The Earth’s climate is like a big engine for redistributing heat from the equator to the poles.  And it does that by means of ocean currents and wind currents.  They tell us, the scientists do, that the Earth’s climate is an non-linear system – just a fancy way they have of saying that the changes are not all just gradual, some of them come suddenly, in big jumps… And so, all those wind and ocean currents that have formed since the last ice age and have been relatively stable – they’re all up in the air – they change. 

And one of the ones they’re most worried about, where they’ve spent a lot of time studying the problem is in the the North Atlantic where the gulf stream comes up and meets the cold winds coming off the Arctic over Greenland and that evaporates the heat out of the gulf stream and the steam is carried over to western Europe by the prevailing winds and the Earth’s rotation.  But isn’t it interesting that the whole ocean current system is all linked together in this loop, they call it the ocean conveyor.

And the red are the warm surface currents, the Gulf Stream is the best known of them.  But the blue represent the cold currents running in the opposite direction…

Up in the North Atlantic, after that heat is pulled out, what’s left behind is colder water, and saltier water, because the salt doesn’t go anywhere. And so, that makes it denser and heavier.  And so that cold heavy dense water sinks at the rate of 5 billion gallons per second.  And then that pulls that current back south.

At the end of the last ice age as the last glacier was receding from North America the ice melted and a giant pool of fresh water formed in North America, and the Great Lakes are the remnants of that huge lake.  An ice dam on the eastern border formed, and one day it broke, and all that fresh water came rushing out, ripping open the St. Lawrence there, and it diluted the salty dense cold water, made it fresher and lighter so it stopped sinking, and that pump shut off.

 And the heat transfer stopped.  And Europe went back into an ice age for another 900 to 1000 years.  And the change from conditions like we have here today to an ice age took place in perhaps as little as ten years time.  So that’s a sudden jump.  Now, of course, that’s not going to happen again because the glaciers of North America are not there… Is there any other big chunk of ice anywhere near there…?  Oh, yeah [Gore says ominously, as the image pans to ice covered Greenland] we’ll come back to that one…

Later in the movie Gore tells us that Greenland is rapidly melting.  The point being that it will provide a massive amount of fresh water that will stop the the thermohaline conveyor and  “would raise sea level almost 20 feet if it ‘went,'” Gore tells us.  He tells us about water seeping to the bottom of the ice sheets where it “lubricates where the ice meets the bedrock” causing the ice to slide toward the ocean.

Then he shows a series of pictures purporting to show the amount of melting in Greenland.  Gore says…

“In 1992 they measured this amount of melting in Greenland … Ten years later this is what happened…And here’s the melting from 2005”

 

Hosing Experiments

But what if…?  What if there were a huge amount of low density fresh water dumped into the North Atlantic where the high density water is supposed to be sinking, just like the giant Canadian lake crashing through the barrier of ice the Gore told us about?  This possibility is explored with computer models known as  “hosing experiments.”  In a hosing experiment a model that simulates the ocean and atmosphere circulation patterns is modified to artificially dump huge amounts of extra fresh water, as if from a giant hose, into some location in the ocean.   It has been found that when enough fresh water is forced in, the circulation can be slowed, but rarely stopped. 

How much fresh water do the hosing experiments use to nearly stop the thermohaline circulation?  Typically (or here), they use one million cubic meters of fresh water per second, for 100 years!!!  (One million cubic meters per second has its own unit name: One Sverdrup or 1 Sv).  How does 1 Sv compare to, say, the rate of water flowing over Niagara Falls?

168,000 cubic  meters of water fall over Niagara Falls every minute.  That is about 2,800 cubic meters of water per second.  So one Sverdrup of water is the same as about 350 Niagara Falls!  (1,000,000 / 2,800  = 357).  So, roughly speaking, if 350 Niagara Falls were dumped into the oceans around Greenland continuously for 100 years, then we could expect to see a significant slow down of the thermohaline circulation.

River systems discharging into the Arctic Ocean.

How does one Sverdrup compare to the freshwater discharge of ALL the rivers emptying into the arctic ocean?  One Sverdrup of fresh water amounts to nearly 32,000 km³ of water per year  (1 Sv  x 10⁶ m³ s^-1/sv x (86,400 s/day) x (365 day/year) = 31,536 km³/year).  The total fresh water discharge from all rivers into the arctic is only about 4,300 km³ per year.  So, typical hosing experiments that nearly stop the overturning circulation add a water volume about 7 times the amount of water from all rivers discharing into the Arctic Ocean combined.

What about Greenland?

Gore ominously implies that the amount of fresh water needed to turn off the overturning circulation is just waiting to pour off of  Greenland, due of course (drum roll), to CO2 induced anthropogenic global warming.   His pictures of Greenland, shown above, imply that about half of Greenland’s 2.8 million cubic kilometers of ice have melted in the 13 years between 1992 and 2005.  This is wildly misleading.  Only a miniscule fraction of the area shown in Gore’s Greenland images actually melts every year.   This is evidenced by mass balance studies, which show Greenland loses on the order of hundred cubic kilometers of ice every year,  which translates into a measly 0.003 Sverdrups.

100 km³ /year= 10¹¹ m³/year

(10¹¹ m³/year) / (365 days/year) / (86,400 seconds/day)
             = 3 x 10³ m³/second
             = 0.003 Sv

Put another way, one Sverdrup of fresh water is 86.4 km³/day.  So the hosing experiments pouring in one Sverdrup put about as much fresh water into the ocean each day (86.4 km³) as Greenland provides in a year (100 km³).

But if Greenland actually started melting, by some extraordinary circumstance,  300 times faster, then it would yield 1 Sverdrup, or 1,000,000 cubic meters, of fresh water every second.  What would happen after 100 years of melting at that rate?  Well, that’s a trick question, because at a melting rate that gives 1 Sverdrup of freshwater Greenland would run out of ice in about 90 years.  This is because Greenland has only 2.85 million cubic kilometers of ice, and one Sverdrup of water is the same as about 31,500 cubic kilometers of water per year.  Ignoring the difference in density between ice and water, then 2.85 million cubic kilometers divided by 31,500 cubic kilometers per year gives 90 years.

Conclusion

You don’t hear as much about the threat of the collapse to the thermohaline circulation today as you did a few years ago.  This is because it has become recognized as being a very far fetched possibility, even by most alarmists who want to maintain a shred of dignity.  But I have a feeling we will not see this wildly exaggerated threat removed from new editions of Gore’s “An Inconvenient Truth” anytime soon.

Return to Criticisms of Al Gore’s “An Inconvenient Truth”

Arctic sea ice gone by 2015? A challenge to David Barber.

Here we go again. Last March I wrote about the media predictions that the Arctic sea ice would be gone by the summer of 2012. As I showed back then, those wild predictions were based on a simple extrapolation of the minimum summer sea ice extents of 2006 and 2007.

 

I’ll repeat the basic facts:

The sea ice area in the Arctic has been monitored by satellite for almost 30 years, since 1979. The area of the ice rises and falls, as you would expect, as the year cycles through its seasons. It reaches its yearly minimum by late September or early October. On the average, this minimum has been declining for the last 30 years. After October the northern sea ice area increases until it reaches a maximum in late March or early April each year. The yearly cycle is huge. Typically, about 60% of the total sea ice area melts away as is goes from yearly maximum to the yearly minimum.

The 2007 melt season was very severe and the Arctic sea ice area anomaly reached its lowest level since satellite tracking began.  But that low level was immediately followed by an unprecedented rise in sea ice area in the Arctic in the months following the 2007 summer melt season. The 2008 melt season was quite severe, but not as severe as the 2007 melt season. In order to go from the minimum ice extent of 2007 to zero ice in 2012, the Arctic sea ice extent minimum needs to drop an average of about 600,000 square kilometers per year. But the Arctic ended up with slightly more ice area (about 100,000 square kilometers more) after the 2008 melt season than after the 2007 melt season.  Figure 1, below sums it up.

Figure 1

New predictions of meltdown

Now along comes David Barber  from the University of Manitoba, who estimates that the Arctic Basin will be ice free by the summer of 2015. The Star Phoenix reports:

The ice that has covered the Arctic basin for a million years will be gone in little more than six years because of global warming, a University of Manitoba geoscientist said. And David Barber said that once the sea ice is gone, more humans will be attracted to the Arctic, bringing with them even more ill effects…He said he estimates the Arctic sea should see its first ice-free summer around 2015…Barber has said before the Arctic basin would be free of summer sea ice some time between 2013 and 2030. But their research about recent changes in the Arctic has allowed them to pinpoint the date even closer.

Barber sounds like a smart guy, and was the scientist in charge of a $40-million Arctic research project, the Circumpolar Flaw Lead System Study. He will present his preliminary findings at the International Arctic Change 2008 conference  in Quebec. However, his track record for predictions is rather spotty. Earlier this year National Geographic reported:

“We’re actually projecting this year that the North Pole may be free of ice for the first time [in history],” David Barber, of the University of Manitoba, told National Geographic News aboard the C.C.G.S. Amundsen, a Canadian research icebreaker.”

Prediction for summer of 2008 didn’t work out

The Arctic sea ice concentration reached its minimum around September 15th this year. Figure 2, below, from the Polar Research Group at the University of Illinois, shows the distribution of ice in the Arctic on that day. As you can see, the North Pole was not even close to being ice free. Figure 3 shows the Arctic Basin sea ice area for the last 365 days. Note that in mid-September the the sea ice area anomaly for the Arctic Basin was about negative 0.75 million square kilometers, but there were still 2.5 million square kilometers of ice yet to melt. Again, not even close to zero.

 Figure 2. Arctic Sea Ice Concentration on September 15th, 2008, when the Arctic sea ice reached its minimum for the year. Image from the University of Illinois Polar Research Group.

 Figure 3. Arctic Basin sea ice area for the last 365 days.  In mid-September the sea ice anomaly was negative 0.75 million square kilometers, but there were 2.5 million square kilometers more than zero.  Image from the University of Illinois Polar Research Group.  Click on image to see clearer version. 

 

Those who like to parse words will note that National Geographic piece did not quote Barber as saying the “Arctic Basin” or the “Arctic Ocean” would be ice free during the summer of 2008.  They will correctly point out that he said “the North Pole.”  My answer to that is “So what.”  The North Pole has certainly seen open water in modern times, as attested to by the following images:

 Figure 4. Skate (SSN-578), surfaced at the North Pole, 17 March 1959. US Navy photo courtesy of tripod.com. This image is from NavSource Online: Submarine Photo Archive

 Figure 5. Seadragon (SSN-584), foreground, and her sister Skate (SSN-578) during a rendezvous at the North Pole in August 1962. Note the men on the ice beyond the submarines. USN photo from The American Submarine, by Norman Polmar. This image is from NavSource Online: Submarine Photo Archive

 

What about Barber’s prediction for 2015?

The December 5th StarPhoenix article mentioned above says that according to Barber, “The ice that has covered the Arctic basin for a million years will be gone in little more than six years because of global warming.”  I wonder if Barber can seriously believe that the Arctic Basin has been continuously ice covered for “a million years.”  There is considerable evidence  that the entire Arctic region was warmer just several thousand years ago than it is now. 

Open water from the northern coast of Greenland to the North Pole likely occurred in the not too distant past.  According to Science Daily, Astrid Lysa and colleagues have studied shore features, driftwood samples, microfossils and shore sediments from Northern Greenland. Science Daily reports:

 “The architecture of a sandy shore depends partly on whether wave activity or pack ice has influenced its formation. Beach ridges, which are generally distinct, very long, broad features running parallel to the shoreline, form when there is wave activity and occasional storms. This requires periodically open water,” Astrid Lyså explains.

Pack-ice ridges which form when drift ice is pressed onto the seashore piling up shore sediments that lie in its path, have a completely different character. They are generally shorter, narrower and more irregular in shape.

“The beach ridges which we have had dated to about 6000-7000 years ago were shaped by wave activity,” says Astrid Lyså. They are located at the mouth of Independence Fjord in North Greenland, on an open, flat plain facing directly onto the Arctic Ocean. Today, drift ice forms a continuous cover from the land here.

Astrid Lyså says that such old beach formations require that the sea all the way to the North Pole was periodically ice free for a long time.

“This stands in sharp contrast to the present-day situation where only ridges piled up by pack ice are being formed,” she says.

Funder and Kjaer reported similar results at the 2007 fall meeting of the American Geophysical Union. They point out that “Presently the North Greenland coastline is permanently beleaguered by pack ice…” but “that for a period in the Early Holocene, probably for a millennium or more, the Arctic Ocean was free of sea ice at least for short periods in the summer.” They date this time period to sometime between 8500 and 6000 years ago.  (Update 7/8/10 – Funder now believes “that multiyear sea ice was reduced to between half and a third of the present during the Holocene Thermal Optimum.”  Thanks to Kevin O’Neill and his persistence  in making this correction.)

An Open Challenge to David Barber

I am concerned about climate exaggerations and the effect  they have on public policy makers.  It seems quite clear that David Barber was off the mark when he predicted that “this year that the North Pole may be free of ice for the first time,” because neither the Arctic Ocean, the Arctic Basin nor the North Pole were ice free this past summer.  The North Pole being ice free is not that unusual, and the entire Arctic was probably ice free a relatively short 7,000 years ago.

Now Barber has made the slightly longer term prediction that “The ice that has covered the Arctic basin for a million years will be gone in little more than six years.”  I propose a friendly wager based on this prediction.  I will bet David Barber $1000(US) that the ice covering the Arctic Basin will not be gone anytime before December 31st, 2015.  The bet would involve no transfer of  cash between myself or Barber, but rather, the loser will pay the sum to a charitable organization designated by the winner.

 Definition of terms.  The Arctic Basin is defined by the regional map at Cryosphere Today.  “Gone” means the Arctic Basin sea ice area is less that 100,000 square kilometers, according to National Center for Environmental Prediction/NOAA as presented at Cryosphere Today .  Charitable organizations will be agreed upon at the time the bet is initiated. 

David Barber is a smart guy and evidently an expert in his field.  Taking on a wager with an amateur like me should be like shooting fish in a barrel.  I look forward to reaching an agreement soon.