Posts Tagged ‘Holocene’


Salmon and Sea-Level

August 8, 2009

I recently wrote about  the alarmist claim that sea level rise in British Columbia is going to have a serious negative impact on their Salmon population.  An environmental activist playing at journalist wrote for the Victoria Times Colonist:

“The spectre of rising sea levels and ecological change from climate disruption show land-use plans for Vancouver Island and the B.C. coast will need to be revisited and recalibrated to account for rapid and unabated climate change.”

“‘Once set in motion, sea-level rise is impossible to stop. The only chance we have to limit sea-level rise to manageable levels is to reduce emissions very quickly, early in this century. Later it will be too late to do much,’ says senior NASA scientist Stefan Rahmstorf in a recent article for the United Nations Office for the Co-ordination of Humanitarian Affairs.”

There may be a lot of man made obstacles to Salmon survival, such as dams, over-fishing, etc., but sea-level rise is not one of them. 

Let’s get right down to the nitty-gritty.

Salmon have been around for about 500,000 to 1,000,000 years, give or take a few hundred thousand.  This is not a praticularly long time, nevertheless, Pacific Salmon diversified into multiple species, including Cherry Salmon, Sockeye Salmon, Chinook Salmon, Pink Salmon, Chum Salmon, and Coho Salmon.  There are also Atlantic Salmon and even land-locked Salmon.

Will the sea level  rise of the 21st century end the salmon’s success?  Not likely.  Take a look at these sea-level rise rates from Alaska, one of the Salmon’s primary habitats:

Yes, that right, the sea level is dropping at almost all locations where it is measured in Alaska.  So, it doesn’t look like sea level rise is likely to be much of a threat to the salmon in Alaska or British Columbia

But let’s pretend for a moment that the seas will rise dramatically over the next century, or longer.  Would the Salmon survive this dire situation?   If the past is any indication, the Salmon should pull through.  Take a good look at the graph of Holocene sea-level in the graph below. 

Image created by Robert A. Rohde / Global Warming Art.  Go to

Image created by Robert A. Rohde / Global Warming Art. Go to

Notice that from about 12,000 14,000 years ago until about 8,000 years ago the sea rose about 120 100 meters.  So, the sea level rose about 2 meters per century for 40 60 straight centuries in the recent (geologically speaking) past!  But the Salmon somehow survived.

What effect did this sea-level rise have on the Salmon’s habitat?  The movie below shows Beringia, consisting of the eastern part of Siberia and Alaska from 21,000 years ago to the present.  Look what happens from 12,000 years ago to 8,000 years ago.  I would judge that as a pretty dramatic change of the Salmon habitat.  Yet they seem to have thrived.  I think they will survive sea-level rise this century.

Barengia 21,000 years ago to present. (NOAA)

Barengia 21,000 years ago to present. (NOAA)


The Thermohaline Circulation Only Stops for Extreme, Unrealistic Models

June 4, 2009

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.

vlcsnap-324533And 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…

vlcsnap-32114Up 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.ani-21

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.

 vlcsnap-549956-smallAnd 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?

Niagara falls168,000 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.

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?

Hosing copyGore 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.


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”


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. 


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