I am not only a global warming skeptic, but a skeptic in general.  I call ‘em as I see ‘em.

There have been some attempts to link the arctic sea ice loss of the last several years to reports of volcanoes under thousands of feet of water in the Gakkel Ridge,

The truth is that all the energy from a volcano the size of Mount St. Helens could only melt 100 square kilometers of three meter thick ice.  This is a trivial amount of ice for the arctic region, which typically oscillates between about 4 million and 14 million square kilometers every year.  100 square kilometers is only one hundred thousandth of the yearly change in Arctic sea ice extent

.

Arctic region showing the location of the Gekkal ridge.  This Google Earthimage, with annotation by Moriarty, obviously does not show the arctic sea ice.

Let’s do some simple math to work this out:

First, how much energy is released by a volcano?  Of course, if varies greatly, but we just need an order of magnitude approximation for now.  A common estimate  for the energy released by the Mount St. Helens explosion is 24 megatons, where a megaton is supposed to be equivalent to the energy released by a million tons of TNT.  A joule is the basic SI unit for energy, and one megaton is equal to 4.2 million billion joules (4.2e+15 joules).  Therefore the 24 megatons released by Mount St. Helens translates into about 100 million billion joules (1.0E+17 joules).  That is:

(4.2E+15 joules/megaton  X  24 megatons  = 1.0E+17 joules).

So now the question is: how much ice could be melted by 100 million billion joules of energy?  It takes about 4 joules to heat one gram of water by 1 degree C.  But it takes many more joules to melt a gram of ice.  The amount of energy needed to melt a gram of a solid to a liquid is called the “heat of fusion.”  The heat of fusion for water is 334 joules per gram.   If we divide the total energy of the volcano by the heat off fusion of water, we will get the number of grams of ice that could be melted.  Doing the math:

1.0E+17 joules   /   334 joules per gram   =   3.0E+14 grams

OK, the energy released by Mount St. Helens would melt about 3.0E+14 (three hundred million million) grams of ice.  A gram of ice is about 1.1 cubic centimeters (1.1 cc), so we can round it to 1 cc just to make things simple.  That means that Mount St Helens released enough energy to melt 3.0E+14 cubic centimeters of ice. 

Let’s get a handle on what “3.0E+14 cubic centimeters of ice” means.  A cubic meter of ice is the same as 1,000,000 cubic centimeters of ice.   So, 3.0E+14 cubic centimeters of ice are the same as 3.0E+8 cubic meters of ice.  Still a pretty big number to grasp.  A sheet of ice that is one meter thick and one square kilometer would have a volume of 1 million cubic meters (1.0E+6 m3).  In this case, 3.0E+8 cubic meters of ice would be the same as 300 square kilometers of ice that is 1 meter thick.

Now we have a number that is easier to deal with.  That is, the energy of Mount St. Helens would be enough to melt 300 square kilometers or ice that is 1 meter thick.  Finally, we’ll make the estimate that the ice is about 3 meters thick in the arctic.  (Of course, it is much thicker some places and much thinner in others.)  Then the energy of Mount St. Helens would melt about 100 square kilometers of ice in the Arctic.

The bottom line

The Arctic goes through some serious changes in sea ice extent every year as the season change.  The sea ice extent changes by about 10 million square kilometers every year.  100 square kilometers is about one hundred thousandth of that.  It would take a thousand volcanos the size of Mount St. Helens every year to account for just 1% of the yearly Arctic ice loss.

I am not only a global warming sceptic, but a skeptic in general.  I call ‘em as I see ‘em.

Mount St Helens explosion, May 18th, 1980.

Criticism of our great system of food delivery because of a slavish adherence to a “green” lifestyle is simply unfair.

Ellen Goodman’s syndicated column for July 3rd introduced us to Roger Doiron.  Doiron belongs to a group called “Kitchen Gardeners.”  According to their web site:

“Kitchen Gardeners are a special breed. They are self-reliant seekers of “the Good Life” who have understood the central role that home-grown and home-cooked food plays in one’s well-being. By seeking an active role in their own sustenance, they are modern-day participants in humankind’s oldest and most basic activity, offering a critical link to our past and positive vision for our future.”

Dorian, also works with the Eat Local Foods Coalition of Maine, a group of…

“organizations and individuals interested in creating a shift towards a locally-based food system that is economically vibrant, environmentally sustainable, and healthy.  To some, food system reform may not seem like a pressing social need. But food issues play a dominant role in a range of critical social issues, including poverty, hunger, corporate power, misuse of workers, loss of community, and environmental degradation. With each food purchase decision, consumers are — wittingly or not —making powerful choices that will determine the kind of future we live in.”

Kitchen Gardeners and the Eat Local Foods Coalition seem to have several laudable goals, but saving energy by avoiding the burden of shipping foods over long distances to consumers is a dubious one.  Goodman tells us of the lawn sign, shown below, in Doiron’s lawn that expresses their concern.

I have heard frequently from people promoting farmer’s markets, local agriculural, and those opposed to large scale agribusiness, that food shipments are a significant energy drain and a major source of those pesky greenhouse gases.  Therefore, the argument goes, we should all be eating locally grown food.  Let’s put this argument to the test.

First, let’s accept Doiron’s claim that “in Maine the average person’s food travels about 1,500 miles from field to grocery store using up about 400 gallons of gas.”  1,500 miles and 400 gallons of gas would be a lot to have a single pizza or head of lettuce delivered.  I assume what Doiron really means is that produce, meat, canned foods, etc. usually travel by loaded semitrailers, which get about 4 miles to the gallon  when loaded.  So Doiron is correct, 1,500 miles would take somewhat less than 400 gallons (1,500 miles / 4 miles per gallon = 375 gallons).

A typical maximum weight of a semitrailer on a US highway is 80,000 pounds.  Being conservative, we can say that 60,000 pounds represents the net weight of the product being shipped.  60,000 pounds is a lot of pizza or lettuce.  If the typical person eats 2 pounds of shipped food per day, then that 400 gallons of gas has brought food to 30,000 people! Or, each gallon of gas has brought food to 75 people.  (60,000 pounds / 2 pounds per person / 400 gallons  =  75 people per gallon)

I like to think in terms of kilowatt-hours.  The energy content of one gallon of diesel fuel is equivalent to about 40 kilowatt-hours.  So, if a gallon of gas brings food to 75 people, that is about a half of a kilowatt-hour per person.  The total energy consumed per person per day in the US is about 250 kilowatt-hours (see calculation, below*).  Consequently, the half kilowatt-hour used to ship food 1500 miles to one person is about 1/500th of that person’s total daily energy consumption.

Put another way, if a single $5 gallon of gas delivers 2 pounds of food 1500 miles to 75 people, then the shipping cost per person is a puny 7 cents.  That sounds like a bargain to me.

Let’s not forget the huge social benefits to having enough to eat, the variety of fresh foods available to us outside the local growing season, and the ability to smooth out the effects of local weather extremes on agriculture that are all due to the shipping industry.  I am sure gardening has many benefits, but saving the energy and cost of shipping is not one of them.  Criticism of our great system of food delivery because of a slavish adherence to a “green” lifestyle is simply unfair.

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* The total energy consumed per person per day in the US is about 250 kilowatt-hours.  This may surprise many people.  This number is derived by dividing the total yearly energy consumption of the United States by 365 days and dividing again by the population (300,000,000 or 3e+8 people).

According to Lawrance Livermoor National Laboratory, the total energy consumed in the US in 2002 was 97 Quads.  One Quad is 293,000,000,000 kilowatt-hours, or 2.93e+11 kWh

97 Quads  X  (2.93e+11 kWh/Quad) / 365 days / 3e+8 people = 259 kWh/day/person

.

The Rocky Mountain News reported on a supposed controversy over a proposal by Xcel Energy to build a new electricity generation plant powered by natural gas in Denver.  This plant would cost under $650 million dollars and have a generating capacity of 480 megawatts.  The RMN points out that critics…

“question the need for the plant, whose estimated cost today is more than $600 million, up from initial estimates of $436 million in November, due in part to escalating costs for labor, steel and equipment.

Opponents argue that renewable sources of energy, such as solar and wind, or energy conservation can substitute for an expensive new plant.”

Really? 

Solar

I wonder if the opponents have checked the cost of solar energy lately.  According to the June 2008 survey results for the Solar Electricity Global Benchmark Price Indices, the cost per watt for industrial sized solar electricity installations is $4.94 per watt.  At that rate it would cost about $2.4 billion to build a 480 megawatt solar plant, four times the cost of the natural gas plant.  But, of course, the gas powered facility can operate near maximum capacity for 24 hours a day, yielding over 11,000 megawatt-hours of energy per day.  The solar powered plant can realisticly operate at its maximum power for about four or five hours a day on the average (in Colorado), and if lucky would yield maybe 3,000 megawatt-hours of energy per day.  To equal the the daily maximum energy output of the gas powered plant, the solar powered plant would actually need to have about four times the installed wattage, and would cost closer to $10 billion!  With typical silicon solar technology of today, such a solar facility would have a footprint of about 15 square kilometers, or roughly 200 times the size of Coors Field, as illustrated in figure 1, below.

Figure 1.  Click on image to enlarge.  About 15 square kilometers of solar arrays would be needed to yield the same energy as a 480 kilowatt natural gas power plant averaged over a typical day.  That is approximately 200 times the size of Coors Field.  This image shows 15 square kilometers compared to downtown Denver with Coors field near the top.  Image is from Google Earth with annotation added by Tom Moriarty.

Wind

 Wind is a better bet than solar at this time, and in the long run is cheaper than gas per kilowatt-hour generated.  It would still be very expensive to install enough wind turbines to be able to match the continuous output of a gas fired plant.  480 megawatts worth of wind turbines would put out 480 megawatts of power if the wind is blowing fast enough.  But when the wind is not blowing fast enough, the the output will be lower.  A multiplicative number, called the “capacity factor” is used to calculate the amount of energy that is produced over time, versus the amount that would have been produced if the turbine had been running at its maximum output 100% of the time.   Roughly speaking, the capacity factor for wind power in Eastern Colorado is about 35%.  The capacity factor for modern gas fired electricity generation would be better than 85%.  So, in order to get the same energy as a 480 megawatt gas fired plant, you would have to install twice as much wind capacity, or about 1000 megawatts.  The realistic installation cost of wind power (with the required transmission lines, etc.) is about $3 per watt, as seen here.  So it would cost about $3 billion dollars worth of wind generation facilities to replace the $600 million natural gas powered plant.

However, even with the high construction cost, wind energy would still be cheaper per kilowatt-hour than gas in the long run.  Gas is expensive and going up, while wind is still free.  But wind has another problem.  When the wind is slow or zero, the power is low or zero.  It doesn’t make any difference how many watts of wind power have been installed when the wind isn’t blowing.  There is no power.  There must always be enough non-wind (and non-solar) power generation capacity to cover the load when the wind isn’t blowing (and the sun isn’t shining).

The folks at Xcel Energy figured this out a long time ago.  That is why our lights are not going out.  They know that wind turbines are a great asset for reducing the load on the more traditional types of power generation, but only when the wind is blowing.  That is why they are already the leading wind power provider in the United States, with over 2500 megawatts of installed wind capacity and plans for more in the future.  But they still must maintain the non-fickle conventional power sources, like gas, or the lights will start going out when the wind stops blowing.

Conservation.

Who can argue with conservation, if it means not being wasteful.  But be careful when some environmental activists says “conservation.”  The Rocky Mountain News article quotes the environmental activist, Leslie Glustrom expressing her reservations about moving from coal to gas.  In another recent opinion piece in the Boulder Daily Camera Glustom wrote:

“The alternative to building gas turbines to meet the summer peak is to begin using modern internet-based tools to manage the demand by cycling non-essential motors, lights, air conditioning and HVAC systems. There are a growing number of firms that develop these high-tech “demand response” systems, but, despite repeated efforts from citizen interveners, Xcel repeatedly refused to explore this powerful form of demand management.”

In other words, “citizen interveners,” (like Glustrom herself, no doubt) would like to use tools to control your use of pesky wasteful things like motors and lights.  Don’t worry, I’m sure they have your best interest in mind.

Conclusion

I am all for solar and wind energy.  Really.  Just click on the “ClimateSanity by Tom Moriarty” tab at the top of this page if you doubt me.  But I believe the market, rather than demands by “activists”  will ultimately lead to a better mix of renewables and non-renewables, with renewables gaining share as they become more cost effective.  As for Ms. Glustrom’s idea to “manage the demand,” I suggest a better alternative would be to have plenty of generating capacity and a varying rate scale for consumers based on the cost of generation by Xcel or the time of day.  That way, as the cost of generation varies with demand consumers can adjust their own practices and manage their own demand, without any help by Ms. Glustrom.

They finally did it.  Today the polar bear was listed as an endangered species.  The New York Times reports 

The Center for Biological Diversity, Greenpeace and the Natural Resources Defense Council filed suit in 2005 to force a listing of the polar bear. The center, based in Arizona, has been explicit about its hopes to use this — and the earlier listing of two species of coral threatened by warming seas — as a legal cudgel to attack proposed coal-fired power plants or other new sources of carbon dioxide emissions.

The thrust of the argument that echoes around the internet and appears over and over again in the popular press is the following sequence: 1. Anthropogenic CO2 causes the planet to heat. 2. This causes more summer ice melt. 3. The longer duration of open water in the summer and fall hampers the bear’s seal hunting and breeding. 4. Bear population diminishes.

There was, in fact, a fairly rapid decrease in Arctic sea ice extent sea ice extent over the last few years.  But the losses were almost entirely recovered in an unprecedented ice build-up of Arctic sea ice in the last months of  2007 and the first months of 2008

The alarmists base their argument on the studies of the bear’s habitat by the IUCN World Conservation Union.   Much has been made of the IUCN’s list of the “observed or predicted trend” for the nineteen sub-populations of polar bears. Most people are not aware that only five of these nineteen populations are listed as “declining.”  These sub-populations are the Southern Beaufort Sea population, Norwegian Bay population, Western Hudson population, Baffin Bay population, and Kane Basin population.

What is the condition of the sea ice for these five populations today? See for yourself in the following graphs of sea ice area.*

Figure 1.  The Beaufort Sea, home of the Southern Beaufort Sea sub-population of polar bears, has had an almost exactly average seasonally adjusted sea ice extent for the last six months.

Figure 2.  The Canadian Archipelago is the home of the Norwegian Bay sub-population of polar bears.  This region has had an average seasonally adjusted ice extent for the last six months.

Figure 3.  The Hudson Bay is the home of the Western Hudson population.  The Hudson Bay seasonally adjusted sea ice extent has hovered around average for the last six months.  Although it has been below average for brief periods in the last month, at the time this post is being written it is slightly above average.

Figure 4.  The Baffin Bay / Newfoundland region contains the Baffin Bay and Kane subpopulations.  For most of the last six months the sea ice extent has been greater than the seasonally adjusted average.

 As the NYT article mentioned above made perfectly clear, this has been a battle over the alarmist’s fear of global warming, not about polar bears per se.  Global warming, they worry, is going to yield an ice free Arctic, and the land bound ice in the Antarctic is on the verge of melting and flooding the coastal regions of the planet.  So, how does the overall global sea ice extent look, as of today?  While it has wiggled up an down about the average since satellites have been measuring it, and it stayed below average for several years, it is currently above average, as shown in figure 5, below.

Figure 5. Global sea ice area and anomaly.  Click on the image to enlarge the most recent anomaly data.  For the last several months the anomaly has been positive.  That is, the seasonally adjusted anomaly has been greater than the 1979 to 2000 average. 

My guess is that most of the alarmists are hoping and praying for a significant meltdown in the Arctic this summer.  Without such a meltdown it won’t be polar bears that are endangered, but their credibility.

*  Data for all figures from the University of Illinois Polar Research Group.  For figures 1 through 4 of the sea ice areas and averages were digitized from the U of I graphs of sea ice areas and anomalies using 48 increments per year.  Then the anomalies were subtracted from the sea ice area to give the 1979 to 2000 average.  Figure 5 is from the U of I web page, with additional annotation by ClimateSanity.

Resistance is futile. 

Our kids have brought book order forms from Scholastic home from school for years.  Over the years we have spent hundreds or thousands of dollars ordering books from them.  Like so many others, Scholastic has jumped on the global warming bandwagon. 

In a recent order form for the Scholastic Arrow Book Club (April 2008) that my 3rd grader brought home we found the usual fare of animal stories, adventure, fantasy, science fiction, history and historical fiction.  But lately, Scholastic has a new category, that I will call “green living.” 

On page three of this issue we find advertisements for the books “Fairy Dust and the Quest for the Egg” (”Can Prilla the fairy outwit Captain Hook…”), a variety of poetry books, including works by Carl Sandburg and Shel Silverstein, and the “Indiana Jones Set” (Three book set for $9.95 where “Indiana Jones finds action and adventure all over the world!”).  Oh, and let’s not forget Al Gore’s “An Inconvenient Truth”.

Figure 1.  Al Gore shares a page with “Fairy Dust and the Quest for the Egg,” Shel Silverstein, and Indiana Jones.  Click on the image for a larger version without my overlay.

Figure2.  Close-up of the ad for Gore’s book.

Scholastic/Orchard also publishes The Down-to-Earth Guide to Global Warming by Laurie David and Cambria Gordon.  David was the producer of Gore’s movie.  In a recent interview with Publisher’s Weekly, David said…

“Kids also are the number one influence on their parents, so if you want to reach the parents, go to the kids.”

David’s editor, Lisa Sandell, added..

“Kids are often attracted to numbers, because it makes an idea tangible and relatable,” she says. “If you say, ‘X number water bottles are thrown away every hour,’ that’s a number they can understand … Kids can often be the arbiters of change. They can come back to their parents and ask, ‘Why don’t you have an EnergyStar appliance?”

The fact is that children don’t really understand the issues as clearly as Sandell thinks they do.  Try asking your third grader this: “Suppose refrigerator A uses 400 kilowatt hours per year and costs $1000, and refrigerator B, which is EnergyStar rated, uses 320 kilowatt hours per year, but costs $1,200.  Which one will cost more if we keep the refrigerator for 10 years and the cost of electricity averages $0.09 per kilowatt hour over that time period?”

Kids are attracted to the “Gee Whiz” effect of big numbers precisely because they don’t understand them. Neither do many adults.  (For example, people are impressed by statements like “Seven times the size of Manhattan” when talking about a piece of collapsing ice shelf, until the numbers are put in perspective.) 

The climate change issue is more about politics than it is about science.  It bothers me, but does not surprise me, that climate change alarmist want to indoctrinate my children as their political tools.

A few quick calculations put the size and effect of latest broken piece of Wilkins ice into perspective

The recent “collapse” of the Wilkins ice shelf is causing quite a stir in the blogosphere.  The issue of disintegrating ice shelves is often entangled with the issue of sea level rise.  The Los Angeles Times carried an AP story on March 25th that reported:

…the western peninsula, which includes the Wilkins Ice Shelf, juts out into the ocean and is warming.  Scientists are most concerned about melting ice in this part of the continent triggering a rise in sea level.

The next day, CNN reported on the Wilkins ice shelf, saying:

…the poles will be the leading edge of what’s happening in the rest of the world as global warming continues.  Even though they seem far away, changes in the polar regions could have an impact on both hemispheres, with sea level rise and changes in climate patterns.

Although most reports do admit that this floating ice will not raise the sea level at all, they paint an ominous picture of land bound glaciers rapidly sliding into the sea.  In fact, the Wilkins ice shelf, like other ice shelves, is the product of a land glacier or ice sheet flowing over the coast and onto the water.

The piece of the ice shelf that broke off over the last month is reported to be 160 square miles (about 400 square kilometers).   It is “up to” 650 feet (200 meters) thick according to the Times Online.  A BBC video report corroborates the thickness by saying “Those cliffs are about 60 feet high,” when referring to the floating ice, which indicates that the total thickness is about 10 times that (because most of it is underwater), or about 600 feet (180 meters).  So, lets say the ice is about 0.2 kilometers thick (200 meters).  Then the total volume of the piece that broke off is about

400 km²  x  0.2 km  = 80 km³

One km³ of water will raise the sea level by a miniscule 2.78 microns (less than 3 millionths of a meter).  So, over the course of time that it took this 80 km³ volume of ice to move from the land to the sea it contributed to the sea level by:

80 km³  x  2.78 microns/km³  =  220 microns  =  0.22 millimeters  =  0.009 inches

That’s not very much, considering that it took many years. 

In general, it takes 360 km³ of water to raise the sea level by 1 mm.  In order for the Antarctic peninsula to contribute 12 inches (about 300 mm) to the sea level in 100 years, it would have to drop 1,080 km³ of ice into the ocean  (more really, because the density of the ice is less than the density of water) EVERY SINGLE YEAR FOR 100 YEARS!!  If the ice at the grounding line (where the ice leaves the land) were 0.33 km thick on average, then more than 3000 km² of ice would have to move into the ocean every single year.  Of course, this estimate is based on the unrealistic assumption that there would be no new ice accumulation on land from precipitation to offset the sea level rise.  The difference in the amount of ice sliding into the sea and the amount of ice building up on land due to snowfall is call the mass balance.

Typical estimates for the ice mass balance in the Antarctic Peninsula are nowhere near the 1,080 km³ (roughly 1,080 Gt).  The mass balance for the entire Antarctic continent doesn’t even come close.  Estimates for the entire continent vary greatly and have huge uncertainties.  Vilaconga and Wahr (2006) estimate a net ice loss of “152 ± 80 cubic kilometers of ice per year, which is equivalent to 0.4 ± 0.2 millimeters of global sea-level rise per year.”  Davis (2005) estimates a net increase in Antarctic ice, which would cause a net drop in sea levels.  Either way, the Antarctic is a very, very long way from any kind of catastrophic meltdown.

Then there is Greenland.  Luthcke (2006) estimates the mass balance for Greenland at a loss of 101 Gigatonnes per year.  This translates into a puny sea level rise of only 0.28 mm per year.

While we are at it, let’s consider James Hansen’s estimate of a 15 foot sea level rise this century. 

On the average, a 15 foot sea level rise in a hundred years translates into 46 millimeters per year, requiring 16,500 km³ of additional water per year!  This is about 65 times the current rate of ice melt, if we accept the mass balances of Vilaconga and Wahr for the Antarctic and Luthcke for Greenland.  If the ice sliding into the ocean is a third of a kilometer thick, then Hansen’s doomsday scenario would require 50,000 square kilometers of ice to move from land to ocean every single year!!!!

The bottom line

Pictures of huge chunks of ice and making scary comparisons like “Seven times the size of Manhattan” may get people excited, but they are not very enlightening.

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Davis, C., et. al., Snowfall-Driven Growth in East Antarctic Ice Sheet Mitigates Recent Sea-Level Rise, Science Vol. 308. no. 5730, pp. 1898 - 1901, 2005  Get copy here

Luthcke, et. al., Recent Greenland Ice Mass Loss by Drainage System from Satellite Gravity Observations, Science, Vol. 314. no. 5803, pp. 1286 - 1289, 2006   Get copy here

Velicogna, I. and Wahr, J., Measurements of Time-Variable Gravity Show Mass Loss in Antarctica, Science, Vol. 311. no. 5768, pp. 1754 - 1756, 2007  Get copy here

You have heard and read it all over the media in the last several months. An Associated Press article picked up by newspapers and the web (See National Geographic version here) reported that one scientist “speculated that summer sea ice could be gone in five years.”  The article warns…

“”The Arctic is screaming,” said Mark Serreze, senior scientist at the government’s snow and ice data center in Boulder, Colorado. “

and

“The Arctic is often cited as the canary in the coal mine for climate warming,” said Zwally, who as a teenager hauled coal. “Now as a sign of climate warming, the canary has died. It is time to start getting out of the coal mines.”

Wow!  Where did this ominously close date of 2012 come from?  The sea ice extent in the Arctic (and Antarctic) has been monitored by satellite for almost 30 years, since 1979.  The extent 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 extent 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 extent melts away as is goes from yearly maximum to the yearly minimum.  Figure 1, below, shows the northern sea ice extent from 1979 to November 2007.  Note the large drop in the yearly minimum sea ice extent by October 2007.  This is the canary that Zwally was talking about.  The prediction of an ice free arctic summer by 2012 comes by simply extrapolating the change in the minimum ice extent between 2006 and 2007 into the future, as shown.

 

Figure 1.  Northern Hemisphere Sea Ice Extent from 1979 to November 2007.  Rapid drop in minimum sea ice extent from 2006 to 2007 is extrapolated to show total loss of ice by 2012. Click on image to enlarge.

Nature, ever the jokester, has had her fun with the climate alarmists since last November.  The Arctic has had more than its usual run up of ice this winter.  Today’s (3/20/0 version of the Northern Hemisphere Sea Ice Extent shows an unprecedented (Ever heard that word before?) run up of ice in the Arctic in the last five months 

 

Figure 2.  Same as figure 1, but updated to March 20th, 2008.  The last five months have shown a rapid ice increase in the Northern Hemisphere. Click on image to enlarge.

The 11 million square kilometer gain in sea ice extent is the greatest seasonal ice gain in history (where history, according to alarmist rhetoric, began in 1979 when satellites started tracking the ice extent).  You can read about a little bit of “pre-history” here.  Take a look at this long list of peer reviewed journal articles showing that the “pre-history” or the Arctic was warmer than the present.

 While we are at it, lets not forget about the Southern Hemisphere.  After all, they didn’t put the word “global” in “global warming” for nothing.  Figure 3, below shows the sea ice extent for the Southern Hemisphere going back to 1979 from the same satellites tracking the northern ice.  The peak at the upper right corner of the graph shows that at about the same time that the Arctic ice was at its lowest “historic” extent, the Antarctic ice was at its highest “unprecedented” extent.

 

Figure 3.  Sea ice extent in the Southern Hemisphere.  Click on image to enlarge.

I would not  predict that the Southern Hemisphere sea ice extent will reach 17 million square kilometers in 2012 by simply extrapolating the increases of the last four years out another four years.  The changes are to complex.  But that never seems to stop the alarmists.

All the graphs in this post are from the University of Illinois Polar Research Group.  They got the data from the National Center for Environmental Prediction/NOAA

I appreciate the detailed write-up that Basil Copelanddid for Anthony Watts’ “Watts Up With That” over the last several days.  However, I think the temperature data is being dangerously over analyzed.  I must agree with Christopher Monckton, as reported here, when considering the recent low tempertures:

“… for goodness sake the one thing we mustn’t do is crow,” he said in an interview. “Yes, the temptation of course is to get excited and say this proves the alarmists wrong. But a single extreme weather event in either direction does not prove anything.” 

We have been rightly critical of the global warming alarmist for years for seizing upon every climate extreme as evidence for climate change.  Let’s not seize on these last few months or low temperatures as the basis for a counter argument.

I have reproduced Basil’s smoothing using the Hodrick-Prescott filter (which I got here) for the UAH temperature data.   The UAH data temperature data runs from 1979 to February of 2008.  But I also repeated the smoothing by ending three months early (Nov. ‘07), six months early (Aug. ‘07), nine months early (May ‘07), and 12 months early (Feb. ‘07).  The entire run, starting in 1979 can be seen if figure 1, below.  Figure 2 zooms in on just the last ten years, and shows the temperature trend at the end of each smoothing run.  This simply demonstrates that this smoothing technique, like most others, can be quite unstable near the beginning and end of a time series.

Figure 1.  Reproduction of Basil Copeland’s Hodrick-Prescott smoothed UAH temperature data.

Figure 2.  Smoothed UAH data zoomed in to last 10 years.  Note how the final slope varies as each 3 month period is removed from the data.

If the recent cold temperatures hold, or continue to drop, then we will have plenty of time to point this out as the trend becomes more obvious.  If the temperatures go back up over the next year or so, then the alarmists will gleefully point out how wrong this analysis is, ultimately giving us less credibility. 

 Thanks again to Anthony Watts and Basil Copeland.  Watts’ “Watts Up With That” is on the front-lines in the battle between hysteria and sanity.  I made a donation to his tip jar today, and recommend that readers give what they can.

Lubos Motl’s blog recently highlighted an exchange between Stefan Rahmstorf and Ricbard Lindzen.  this peaked my interest because I have already picked apart another paper by Rahmstorf.  Rahmstorf’s part of the exchange is from chapter 3 (which he wrote) of the book Global Warming: Looking Beyond Kyoto,published in paperback in December of 2007.  You can see Rahmstorf’s chapter here.

 Rahmstorf shows the same CO2 vs. time and temperature vs. time data overlay that Al Gore used in An Inconvenient Truth.  Figure 1, below, shows part of page 36 of Rahmstorf’s chapter in the book.  The image shown in Rahmstorf’s paper notes the source of his data as “Climate and Atmospheric History of the Past 420,000 Years from the Vostok Ice Core, Antarctica, Nature 399 (June 1999): 429-36″ by Petit, et. al.

Figure 1. Excerpt from Rahmstorf’s chapter in Global Warming: Looking Beyond Kyoto.  Rahmstorf added the points for 1959 and 2005 in a similar fashion to Al Gore.

But Rahmstorf forgot to mention that original source of his data included insolation vs. time, along with CO2 vs. time and temperature vs. time.  Figure 2, below, shows an excerpt from Petit’s original paper, in Nature, in which I have highlighed all three parameters vs. time.  Note that Rahmstorf puts the present at the right and the past at the left.  Petit has present at the left and the past at the right.  Other than that, and the fact that Rahmstorf leaves out the insolation data, they are the same.

Figure 2.  Excerpt from Petit’s Nature paper.  This is Rahmstorf’s source, but Rahmstorf leaves out the insolation vs. time data

It is not possible for the CO2 level or the temperature to control the insolation.  It is clear that the temperature and the CO2 can only follow the insolation.  There doesn’t seem to be any likely mechanism for the insolation to directly impact the CO2 level.  Therefore, the insolation must influence the temperature, and the temperature influences the CO2 level.  There may be a small feedback to the temperature from the CO2, but it cannot be large.  This is evidenced by the fact that no matter how high the CO2 goes the temperature still follows the insolation back down. 

In figure 3, below, I have digitized the temperature, CO2 level and insolation from Petit’s data and plotted the temperature series with the CO2 series and again with the insolation series for the last 150,000 years.  Temperature obviously correlates better with insolation than with CO2

Figure 3.  Digitized versions of Petit’s data.  Why does Rahmstorf leave the insolation out of his presentation?

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

An Inconvenient Truth claims that a study showed that polar bears had drowned due to disappearing arctic ice. It turned out that Mr Gore had misread the study: in fact four polar bears drowned and this was because of a particularly violent storm.

The thrust of the argument that echoes around the internet and appears over and over again in the popular press is the following sequence: 1. Anthropogenic CO2 causes the planet to heat. 2. This causes more summer ice melt. 3. The longer duration of open water in the summer and fall hampers the bear’s seal hunting and breeding. 4. Bear population diminishes.

Do a Google search on “polar bear,” “summer,” “ice” and “seals” and you will find an endless chorus singing this tune. A typical refrain of this song was recently sung in this Salt Lake Tribune editorial:

“Scientists know that the bears are in trouble, and they know it is because the sea ice on which they live is melting. Summer ice decreased 8.59 percent per decade between 1979 and 2006. At this rate, the Arctic Ocean sea ice will disappear by 2060, sooner if the rate escalates. Since polar bears depend on sea ice to hunt, breed and travel, the loss of it seems an obvious threat to their survival. The Center for Biological Diversity makes this point in its 154-page petition for listing polar bears as endangered.”

There are three major arguments against the claim that disappearing ice, due to anthropogenic global warming, has severely impacted polar bear populations in recent decades:1. All indications are that as temperatures have risen over the last several decades, polar bear populations have also risen.2. It is quite clear the polar bears have survived periods of less Arctic ice than exists today.3. Claims that current polar bear populations are being stressed by shrinking ice are greatly exaggerated.

Polar bear populations have risen as temperatures have risen.

It is clear that polar bear populations on the average have increased since the 1970s, about the same time temperatures started increasing in North America after several decades of no change or decline. There is strong agreement that the world population of polar bears is about 25,000 today. There is more controversy over what the population was in the 1970s. Reports range from 5,000 to 10,000.

There are some fringe arguments that the population in the 1970s was significantly higher than reported (and therefore subsequent reported increases smaller), but this flies in the face of the bulk of expert opinion and the experience of natives living and hunting in the effected regions. Those that argue the population was under counted in the 70s would be loath to say that the international hunting restrictions based on those low counts were therefore unnecessary.

But didn’t those same international hunting regulations negotiated and implemented in the 70s result in the increasing populations. Yes, they must be a contributing factor. To compare the impact of hunting to other causes of death, the other causes must also be quantified. But there is little accurate mortality information. The USGS’ Arctic Refuge Coastal Plain Terrestrial Wildlife Research Summaries states “Natural mortalities were not commonly observed among prime age animals, and we still know little about the proximate causes of natural deaths among polar bears.”

The world polar bear population is divided up into nineteen subpopulations. The IUCN World Conservation Union’s most recent polar bear population status reviews lists the “observed or predicted trend” for only five of these nineteen subpopulations as “declining.” These five subpopulations will be considered here one at a time:

Southern Beaufort Sea population. According to the IUCN’s analysis, early estimates (1986, 1988, and 1995) of this group put the population at about 1,800 bears. More recent data, collected between 2001 and 2006 put the number at 1,526. A definite decline, right? Not so fast, the IUCN puts the 95% confidence range for this number at 1,211 to 1841 bears. That is more than ± 20%. Oddly, no 95% confidence levels are mentioned for the earlier, higher estimates. But it is a pretty safe bet that those earlier estimates have an even higher uncertainty. Therefore, the old and new estimates are statistically not much different, which is acknowledged in the IUCN’s report.

Norwegian Bay population. Declines in this population can hardly be caused by reduced sea ice due to global warming (anthropogenic or otherwise). Why? Because, according to the IUCN “The preponderance of heavy multi-year ice through most of the central and western areas has resulted in low densities of ringed seals (Kingsley et al. 1985) and, consequently, low densities of polar bears.” (emphasis added)

Baffin Bay population. The IUCN says that the initial estimate (1984-1989) for this subpopulation was 300 to 600 bears. A second survey (1993 to 1997) estimated this declining population to be 2,074 bears. Please note that the previous two sentences are not the result of some bizarre typo. The extremely low initial numbers were presumably due to a flawed methodology (“…data collected in the spring in which the capture effort was restricted to shore-fast ice and the floe edge off northeast Baffin Island…” while “…recent work has shown that an unknown proportion of the subpopulation is typically offshore during the spring…”) How can the IUCN confidently conclude that this subpopulation is decreasing? Because the current (2004) estimate “based on simulations” is that the population is 1,600 bears. The reason for the decline is that the “subpopulation appears to be substantially over-harvested.” One of the reasons that it is over-harvested is that in 2004 Nunavut increased its hunting quota from 64 to 105 bears per year because “reports from Inuit hunters that polar bear numbers in BB had grown substantially.” Note that nowhere in this Orwellian story is the “decrease” in the Baffin Bay polar bear population blamed on receding summer ice due to global warming.

Kane Basin population. The only estimate of the Kane Basin population provided by the IUCN is 164, with a standard error of 35, and is undated. This represents about 0.65% of the world population of polar bears. The IUCN says that on the Greenland side of Kane Basin “the best estimate of the Greenland kill is 10 bears per year during 1999–2003.” The Canadian side has a hunting quota of 5 bears per year. If these numbers are at all accurate, with 10% of the bears being harvested each year, then this population is unsustainable and will clearly decline. However, no mention is made about decreasing summer ice being at all responsible for a decline. In fact, the IUCN says “the habitat appears suitable for polar bears on both the Greenland and Canadian sides of Kane Basin… and could be managed for subpopulation increase.”

Western Hudson population. There is a genuine decline in this population. According to the IUCN “Between 1987 and 2004” this population has gone “from 1,194 (95% CI = 1020, 136 to 935 (95% CI = 794, 1076), a reduction of about 22%.” If the 95% confidence levels are ignored , this is a drop of about 10 bears per year over the 17 year period from 1987 to 2004. It is interesting to note that the government of Nunavut (which covers the northern portion of the western Hudson bear population) increased its hunting quota from 55 to 64 bears for the western Hudson subpopulation in 2004. At that rate, the number of bears harvested from this subpopulation every three years in the northern region alone is about equal to the entire 17 year decline for the entire region.

Polar bears have survived periods of less artic ice than exists today.Polar bears have been around for a long time. According to the USGS “Polar bear genetics indicate that the species branched off from brown bears (Ursus arctos) and invaded an open niche on the surface of the sea ice during maximal extent of the continental ice sheets in the very late Pleistocene. Molecular genetic techniques suggest this could have occurred as long ago as 250,000 years.”We live in the Holocene epoch, the time since the end of the last ice age. This relatively warm period, or interglacial, is about 11,000 years old. The Holocene epoch is one of two epochs contained in the Quaternary period, which is about 1.8 million years old. The other epoch in the Quaternary period is called Pleistocene. The thing that distinguishes the Quaternary period from the previous 65 million year old Tertiary period is that the Quaternary period is a “glacial age,” that is, on the average the planet has been colder than it previously was in the Tertiary period. The Quaternary Research Association describes the Quaternary as “…characterised by long periods (c.100,000 years) of cold climates interspersed with shorter periods (c.10-15,000 years) of warmer conditions.” Figure 1, below, shows a temperature proxy for the entire 1.8 million year Quaternary. Our current epoch, the Holocene, is one of those warmer periods, or interglacials.

Figure 1. 2.6 million years of climate as represented by and oxygen isotope temperature proxy. Peaks represent a warm earth, troughs a cold earth. The present is on the left side of the graph. The Quaternary is the last 1.8 million years. The narrow peaks in the Quaternary are the interglacials. Graph is from the Quaternary Research Association.

The previous 20, or so, interglacials in the Quaternary do not have the privilege of having their own epoch names simply because they did not occur during the era of modern civilization, and are therefore not as important to us today. But they were just as real as the Holocene. You can see these warm interglacials throughout the Quaternary in the oxygen isotope record, which serves as a temperature proxy, shown in figure 1 above. You can also see the last few interglacials from Gore’s “An Inconvenient Truth” temperature graph (also from proxy data) on pages 66 and 67 of his book, reproduced in figure 2, below. One thing jumps out: some of the previous interglacials were warmer than our current interglacial, the Holocene. This can clearly be seen to be the case for the interglacial previous to the one we are living in now (known as the Eemian interglacial).

Figure 2. Gore’s “famous” temperature plot from pages 66 and 67 of “An Inconvenient Truth.” I’ve blown up the plot and labeled the Holocene (the current interglacial) and the Eemian (the previous interglacial). Even Gore’s data makes it plain that polar bears have survived much warmer periods than they are dealing with now.

Francis, et.al. (2006) used sediment cores at two lakes on Baffin Island, in the northern Canadian Arctic Archipelago to clearly show that the temperatures were considerably warmer during the previous interglacial (the Eemian), 120,000 years ago, than during the present interglacial (the Holocene). The authors conclude:“During the last interglacial, summer water temperature estimates are warmer than at any time during the Holocene period at both sites. At Fog Lake, water temperature estimates for the interglacial are approximately 9 to 12 °C, compared with 5 °C at present. At Brother of Fog Lake, water temperature estimates for the last interglacial range as high as 16 °C, and throughout the peak of the interglacial average between 14 and 15 °C, whereas present temperatures are estimated to be only 6 °C … Our reconstructions illustrate that the previous interglacial in this region of the Canadian Arctic was warmer than at any time during the Holocene period.”The 49 authors from 16 institutions in North America, Europe and Asia, collectively known as members of the North Greenland Ice Core Project (NGRIP), analyzed two ice cores from central Greenland. They reported in High-resolution record of Northern Hemisphere climate extending into the last interglacial period, in Nature in 2004 that “The oxygen isotopes in the ice imply that climate was stable during the last interglacial period, with temperatures 5 °C warmer than today.”But what about the Holocene itself? A plethora a data from multiple sources make it plain that in the arctic the early Holocene was warmer than it is today in the late Holocene, and that areas that are permanently covered with ice today were ice free earlier in this epoch.The paper by Francis, et. al., mentioned above says, when referring to the Holocene, that all proxies indicate “…a warm period in the first half of the
Holocene followed by gradual cooling up to the present”The following four papers confirm high temperatures in the arctic in the early Holocene:

1. A very interesting paper by Fisher, et. al. (2006) shows that the Bering Sea stock of bowhead whales and the Davis Strait stock of bowhead whales, which today are separated from each other by permanent sea ice were able to intermingle from about 10,700 years ago to about 8,900 years ago. Therefore the passage must have been ice-free at that time.

2. Koerner (1990) showed, based on the melt layers of High arctic ice cores, that in the Arctic “The warmest summers occurred 8-10 kyr ago and the coldest only 150 years ago.” So, not only was it the coldest early in the Holocene, but today’s warming seems to be a recovery from the coldest time in the Holocene.

3. In “Centennial-to-millennial-scale periodicities of Holocene climate and sediment injections off the western Barents shelf, 75°N”, Sarnthein, et. al., Boreas, Vol 32, 2003. Sediments “reveal a very early Holocene thermal optimum 10.7–7.7 kyr BP, with summer sea surface temperatures (SST) of 8°C.”

4. “Regional signatures of changing landscape and climate of northern central Siberia in the Holocene”, V.L. Koshkarova and A.D. Koshkarov, Russian Geology and Geophysics, Vol 45 No.6, 2004. In this paper “25 sections of Holocene deposits and soils of northern Central Siberia were studied” and demonstrated that “The main peaks of climatic changes of the postglacial history have been detected in the ranges 8.5-8.0 ka (thermal maximum) and 2.5-2.0 ka (thermal minimum),” where “the thermal maximum is characterized by warming up by 3- 9 °C in the winter, and by 2- 6 °C, in the summer.”

The mid-Holocene also appears to be warmer than the present as demonstrated in the following sources, which are graphically summarized in figure 3, below:

1. Solovieva and Jones(2002) studied a multi-proxy record of the Kola Peninsula in northern Russia concluded that for the period from 8000 years ago to 5400 years ago “A maximum of forest cover and the high Pinus abundance during this period indicate the Holocene climate optimum. The multiproxy data from Chuna Lake generally agree with the temperature reconstructions based on the evidence from the Greenland ice-cores (Stuiver et al., 1995) and summer temperatures were likely to have been 2°–3 °C higher than at present.”

2. Stewart and England (1983) examined more than 70 samples or Holocene driftwood on Ellesmere at 82° N Latitude. The time distribution of the driftwood indicates “prolonged climatic amelioration at the highest terrestrial latitudes of the northern hemisphere” from 4200 to 6000 years before the present.

3. MacDonald, et. al., (2000) dated Scots Pine wood (Pinus sylvestris L.) in Russia’s Kola Peninsula and found “the density of trees north of the modern tree-line was greatest between 7000 and 5000 BP.

4. Sarnthein, et. al.,(2003) studied sediments on the Barents shelf and found “disappearing sea ice from 6.4–5.2” thousand years before the present, and again “3.0–1.6 kyr BP.”

5. Matul, et. al., (2007) from the Russian Academy of Science studied microfossils from the Laptev Sea, which is north of Siberia and well within the Artic circle. They found that “Judging from the increased diversity and abundance of the benthic foraminifers, the appearance of moderately thermophilic diatom species, and the presence of forest tundra (instead of tundra) pollen, the Medieval warming exceeded the recent “industrial” one and is reflected in the near-delta sediments.” But they indicate that it was warmer even earlier by saying “..the warming in the Laptev Sea during the period of ~5100–6200 years B.P. corresponding to the Holocene climatic optimum could be even more significant as compared with the Medieval Warm Period.”

6. Koshkarova and Koshkarov (2004) draw their conclusions based on “25 sections of Holocene deposits and soils of northern Central Siberia [that] were studied by paleocarpological methods. Special attention was given to the reconstruction of the dynamics of speciation of forest cover in time and space.” These 25 sections are all above the arctic circle and range in longitude from 86 to 190°E. They conclude “The main peaks of climatic changes of the postglacial history have been detected in the ranges 8.5-8.0 ka (thermal maximum) and 2.5-2.0 ka (thermal minimum). Importantly, the thermal maximum is characterized by warming up by 3 - 9 °C in the winter, and by 2 - 6 °C, in the summer.”

7. Lawson, et. al., (2007) looked at glacial advances and retreats in Glacier Bay, Alaska. Glacier Bay is well south of the Arctic circle, but yields a rich history of northern latitude temperatures. They found a glacial retreat starting 6800 ago followed by a new glacial advance starting 5000 years ago. The retreat “was long enough to develop a mature forest.”

8. Francis, et. al., (2006) judged surface water temperatures on Baffin Island in the Canadian Arctic by analyzing midge remains in sediment cores. They report “a warm period in the first half of the Holocene followed by gradual cooling up to the present.”

9. In their study of Holocene temperatures in Iceland, Caseldine, et. al., (2006), analyzed chironomids and pollens from lake sediment cores and tree-line data. They show “that optimal summer warmth did not occur in Iceland until 8 kcal. yr BP at the earliest, possibly lasting until 6.7 kcal. yr BP. The amount of warming for July was therefore at least 1.5 °C, but possibly up to 2–3 °C higher than the 1961–1990 average.”

10. “Pollen, stomata, and macrofossils in a lake core with a basal date of 9700 14C BP were used to reconstruct past changes in climate and vegetation in the arctic tree line area, northeast European Russia” by Kultti, et. al. (2004a) They state in their abstact “We interpret summer temperatures to have been ca. 3–4 °C higher between ca. 8900 and 5500 BP than at present, and the lowest temperature regime of the Holocene to have occurred between 2700 and 2100 BP.”

11. In a very comprehensive study of the western Arctic Kaufman and coauthors from the US, UK, Canada, Norway, Iceland, and Russia (2004), studied proxies from over 140 sites in the western hemisphere part of the arctic. Their abstract notes “Paleoclimate inferences based on a wide variety of proxy indicators provide clear evidence for warmer-than-present conditions at 120 of these sites. At the 16 terrestrial sites where quantitative estimates have been obtained, local HTM[Holocene Thermal Maximum] temperatures (primarily summer estimates) were on average 1.6 ± 0.8 ° C higher than present…” They found the timing for the thermal maximum to be a function of the longitude. The thermal maximum started earliest in the farthest west region, referred to as Beringia (Alaska and far eastern Siberia), perhaps as early as 11,000 years ago. Then, “HTM conditions in the Canadian Arctic Islands and the Greenland–Iceland regions, were reached 8.6±1.6 ka, with all but two sites reporting clear evidence of an HTM.” Once started, the thermal maximum lasted a long time: “On average, it lasted 2200±1300 yr in central and eastern Beringia, compared with 3100±1700 yr in northern continental Canada, and 3400±1400 in the Canadian Arctic Islands and Greenland–Iceland.”

12. In another paper, Kultti, et. al., (2004b) looked at tree lines in Finnish Lapland and found “Results indicate that pine reached its maximum distribution between 8300 and 4000 cal. yr BP. The inferred minimum shift in mean July temperature was at that time c. +2.5.”

Figure 3. It is commonly accepted among paleontologists that the Arctic was warmer in the early and mid-Holocene than at the presen. This graph shows a summary of the papers mentioned above as evidence for higher temperatures in the mid-Holocene. The left side of the graph shows the journal titles and authors. The right side shows a quote from the paper and period when the author provides evidence that it was warrmer than the present. These papers are representative of arctic areas over a wide range of longitutes in both the east and west hemispheres. Click on the image to see a larger version.

Stress on polar bear populations is greatly exagerated.

I have made a concerted effort to trace the stories about the drowning deaths of polar bears, as expressed in dozens of popular press articles and by many special interest groups, back to their roots. It appears that all such stories that can be traced at all go back to the same incident. This incident was reported by Monnett and Gleason (2006). Even they state “To our knowledge, we report here the first observations of polar bears floating dead offshore and presumed drowned while making apparent long-distance movements in open water.” (Emphasis added.) The circumstances of the drowning were extreme, as the authors explain: “Our observations suggest that polar bears swimming in open water near Kaktovik drowned during a period of high winds and correspondingly rough sea conditions between 10 and 13 September 2004” Somehow this single incident has been extrapolated to the impending extinction of polar bears due to anthropogenic global warming.

Caseldine, C., Langdona, P., and Holmes, N., Early Holocene climate variability and the timing and extent of the Holocene thermal maximum (HTM) in northern Iceland, Quaternary Science Reviews, Volume 25, Issues 17-18, September 2006. Get copy hereFisher, D., et. al., Natural Variability of Arctic Sea Ice Over the Holocene, EOS Transactions American Geophysical Union, Vol 87, No 28, 2006. Get copy hereFrancis, et.al. Interglacial and Holocene temperature reconstructions based on midge remains in sediments of two lakes from Baffin Island, Nunavut, Arctic Canada, Palaeogeography, Palaeoclimatology, Palaeoecology, 2006. Get copy hereKaufman, D. S., et. al., Holocene thermal maximum in the western Arctic (0–180°W), Quaternary Science Reviews, Vol 23, 2004. Get copy hereKoshkarova, V.L., and Koshkarov, A.D., Regional Signatures of changing Landscape and Climate of Northern Central Siberia in the Holocene, Russian Geology and Geophysics, Vol. 45, № 6, 2004. Get copy hereKoerner, et. al., A record of Holocene summer climate from a Canadian high-Arctic ice core, Nature, Vol 343, 1990. Get copy here

Kultti, S., Oksanen, P., and Väliranta, M., Holocene tree line, permafrost, and climate dynamics in the Nenets Region, East European Arctic, Canadian Journal of Earth Science, Vol 41, 2004a. Get copy here

Kultti, S., et. al., Past changes in the Scots pine forest line and climate in Finnish Lapland: a study based on megafossils, lake sediments, and GIS-based vegetation and climate data,” The Holocene, Vol 16 No3, 2004b. Get copy here

Lawson, D.E.,et. al., 2007, Early to mid-Holocene glacier fluctuations in Glacier Bay, Alaska, in Piatt, J.F., and Gende, S.M., eds., Proceedings of the Fourth Glacier Bay Science Symposium, October 26–28, 2004: U.S. Geological Survey Scientific Investigations Report 2007-5047, p. 54-55. Get copy here

MacDonald, G., et. al., Radiocarbon dated Pinus sylvestris L. wood from beyond tree-line on the Kola Peninsula, Russia, The Holocene, Vol. 10, No.1, 2000. Get copy here

Matul, A. G., et. al., Recent and Late Holocene Environments on the Southeastern Shelf of the Laptev Sea As Inferred from Microfossil Data, Oceanology, Vol. 47, No. 1, 2007. Get copy here

Sarnthein, et. al., Centennial-to-millennial-scale periodicities of Holocene climate and sediment injections off the western Barents shelf, 75°N, Boreas, Vol. 32, 2003. Get copy here

Solovieva, N., and Jones, V., A multiproxy record of Holocene environmental
changes in the central Kola Peninsula, northwest Russia, Journal of Quaternary Science, 17(4), 2002. Get copy here

Stewart, T. and England, J., Holocene Sea-Ice Variations and Paleoenvironmental Change, Northernmost Ellesmere Island, NWT., Canada, Arctic and Alpine Research, Vol 15, No. 1, 1983. Get copy here

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