The Greenland Ice Melt: Should We Be Alarmed?

by Marlo Lewis on July 26, 2012

in Features

Post image for The Greenland Ice Melt: Should We Be Alarmed?

If you follow global warming news at all, you’ve probably seen the NASA satellite images (above) many times. The images show the extent of Greenland surface ice melt on July 8 (left) and July 12 (right). In just a few days, the area of the ice sheet with surface melting increased from about 40% to 97%, including Summit Station, Greenland’s highest and coldest spot.

NASA took a drubbing from Patrick Michaels and Chip Knappenberger at World Climate Report (“Illiteracy at NASA“) for describing the ice melt as “unprecedented” in the title of the agency’s press release. The word literally means without precedent, and properly refers to events that are unique and never happened before. In reality, as one of NASA’s experts points out in the press release, over the past 10,000 years, such events have occurred about once every 150 years:

“Ice cores from Summit show that melting events of this type occur about once every 150 years on average. With the last one happening in 1889, this event is right on time,” says Lora Koenig, a Goddard glaciologist and a member of the research team analyzing the satellite data.

Equating ’rare yet periodic’ with ‘unprecedented’ is incorrect and misleading. “But apparently,” comment Michaels and Knappenberger, “when it comes to hyping anthropogenic global warming (or at least the inference thereto), redefining English words in order to garner more attention is a perfectly acceptable practice.” New York Times blogger Andrew Revkin also chided NASA for an “inaccurate headline” and the associated “hyperventilating coverage,” but for a different reason: NASA provided “fodder for those whose passion or job is largely aimed at spreading doubt about science pointing to consequential greenhouse-driven warming.”

Enough on the spin. Let’s examine the real issues: (1) Did anthropogenic global warming cause the extraordinary increase in surface melting between July 8 and July 12? (2) How worried should we be about Greenland’s potential impact on sea-level rise?

The answer to question (1) is that greenhouse warming does not appear to be the cause. Revkin links to a graph that shows similar melting events at Summit Station not only in 1889 but also in Medieval times, centuries before the advent of SUVs and coal-fired power plants.

NASA, moreover, ascribes the rapid expansion in surface ice melt to a high pressure blocking pattern, the same phenomenon that produced the recent heat wave and drought in the U.S. Midwest. NASA reports:

This extreme melt event coincided with an unusually strong ridge of warm air, or a heat dome, over Greenland. The ridge was one of a series that has dominated Greenland’s weather since the end of May. “Each successive ridge has been stronger than the previous one,” said [Thomas] Mote [a climatologist at the University of Georgia]. This latest heat dome started to move over Greenland on July 8, and then parked itself over the ice sheet about three days later.

There is no known link between such blocking patterns and global climate change. It’s also worth noting that the dramatic surface ice melt began to reverse around July 14th. Greenland did not shift into a new climate regime.

If such events start to occur more frequently than once every 80-250 years, a global warming link would be more credible. As Prof Eric Wolff of the British Antarctic Survey told BBC News: “While this is very unusual, as always we cannot attribute any individual extreme event to climate change: We will have to wait and see if more such events occur in the next few years to understand its significance for both the climate and the health of the ice sheet.”

On to question (2): How much ice is Greenland shedding, and what are the implications for global sea-level rise? A study published in Science magazine in 2006 by Scott Luthcke of NASA and colleagues used satellite gravity measurements to estimate annual net ice loss in Greenland from 2003 to 2005. The researchers estimated that the ice sheet gained 55 gigatons per year from snowfall at higher elevations and lost 155 gigatons per year at lower elevations, yielding a net annual ice loss of 101 gigatons. That translates into an annual loss of 27 cubic miles of ice per year, or 2,700 cubic miles per century. Sounds huge — until you compare it to Greenland’s total ice mass. The Greenland Ice Sheet holds 706,000 cubic miles of ice. So at the 2003-2005 ice loss rate, Greenland will lose less than 4/10th of 1% of its ice mass in the 21st century. Apocalypse not.

Pat Michaels reviews a more recent gravity measurement study (Wu. et al. 2010, published in NatureGeoscience) that estimates ice mass balances in both Greenland and Antarctica from 2002 to 2008. Similar to the Luthcke study, the Wu team finds that Greenland’s net ice loss is 104 gigatons per year. They also estimate that Antarctica is losing 87 gigatons per year. What does it mean for sea-level rise? Pat comments:

It takes about 37.4 gigatons of ice loss to raise the global sea level 0.1 millimeter—four hundredths of an inch. In other words, ice loss from Greenland is currently contributing just over one-fourth of a millimeter of sea level rise per year, or one one-hundreth of an inch.  Antarctica’s contribution is just under one-fourth of a millimeter per year.  So together, these two regions—which contain 99% of all the land ice on earth—are losing ice at a rate which leads to an annual sea level rise of one half of one millimeter per year. This is equivalent to a bit less than 2 hundredths of an inch per year.  If this continues for the next 90 years, the total sea level rise contributed by Greenland and Antarctica by the year 2100 will amount to less than 2 inches.

Couple this with maybe 6-8 inches from the fact that the ocean rises with increasing temperatures, and 2-3 inches from melting of other land-based ice, and you get a sum total of about one foot of additional rise by century’s end.

An additional foot of sea level rise is less than a third the amount (“more than a meter“) forecast by a group of alarmist scientists calling themselves the “Copenhagan Consensus.” It is small potatoes compared to the 18-20 feet of sea-level rise Al Gore warned us about in An Inconvenient Truth. An additional foot of sea level rise is about twice the amount the world has experienced since 1880. There were surely costs associated with sea-level rise in the 20th century, but as a factor affecting public health and welfare it was so trivial most people never noticed. Our wealthier, more mobile, and more technologically advanced children’s children’s children should be able to adapt to 12 inches of sea-level rise and do just fine.

Gail July 26, 2012 at 5:00 pm

Greenland, past and present

Marco July 26, 2012 at 6:21 pm

WHAT ARE WE GOING TO DO NOW – Plaese explain – Is it better if I migrate to the Emirates. Throws a F – kin BONE. Thank you.

Respectfully,
Marco.

Gregg July 26, 2012 at 8:01 pm

The network news made it sound like the whole thing melted off down to bare earth.

Dave July 27, 2012 at 3:41 am

“.. for the next 90 years, the total sea level rise contributed by Greenland and Antarctica by the year 2100 will amount to less than 2 inches.”

THIS I believe IS INCORRECT, because from my own experience, going back to yr. 2000
at Mer Island Torres Strait -Australia [between Papua New Guinea and Australia] while there, I noticed that the king-tide level was up to the level
of the sand bank some 4-5 feet high from the normal beach level.
In year 1965 I remember the k/tide level was [in the same place]
12-14 feet from the edge of the drop of the continental shelf. [My island is a volcanic mountain jutting out from the sea].
This means that the level [in yr. 2000] rose some 10 feet in 35 years,
that’s roughly 3-1/2 feet [give or take a few feet due to situation in the weather
and other events] every year for 35 years….
and this was just from normal ‘slow’ melting of the ice off
the two ice-continents.

It is to a genuine scientific studies and research based fact that,
-if all of Greenland ice would melt
the global sea level would rise to about 20ft; and
-if all of Antarctica’s ice would melt [Greenland in size
would fit into Antarctica about five(5) times so it] means that
global sea level rise would be about 100ft plus that of Greenland
to reach 120ft. THIS IS NOT A HIGH-TIDE or LOW-TIDE situation.
WHEN THE TIDE WILL RISE, IT WILL KEEP ON RISING UNTIL IT
REACHES THE LIMIT OF 120ft, meaning, NO COASTAL COMMUNITIES WORLDWIDE WOULD EVER EXIST -they have to be moved to higher ground NOW!

Earthling July 28, 2012 at 5:39 am

We certainly could be alarmed, but what good that would do is questionable, especially as the melt is a natural event.

virgil July 28, 2012 at 3:45 pm

Please review your calculations of sea level rise. Since you say that 37.4 gigatons raises the level by 4 hundredths of an inch, then the 104 gigatons a year would raise the sea level by 11 hundredths of an inch per year (104/37.4*4). A similar calcuation of the Antarctic’s 87 gigatons gets me 9 hundredths, for a total of 2 tenths of an inch per year. Over 90 years that would get us 18 inches. That compares with your less than 2 inches. Still nothing to get alarmed over, but I think you should review the math.

Dale July 28, 2012 at 10:00 pm

Pointing out that such an event as happened before or the minimal change in sea level does not dismiss the monumental sign that our planet is in trouble. When something like this happens the only thing that people want to hear is that everything is ok. We read articles like this one and feel relieved knowing that such events have occurred in the past and we are still here. Somehow this makes it easy for us to ignore all of the other signs. We go on about our lives and tell our friends not to worry because it’s all one big cycle and it really doesn’t mean anything. To that I say WAKE UP PEOPLE. Stop looking for reasons not to worry and start looking at the big picture. In the past five years we have seen more weather related anomalies than we have seen in the past eighty years. We have seen hurricanes in the Gulf, tsunamis’ and massive earthquakes in areas that have never seen seismic activity before. Last year we had a swarm of tornados hundreds of miles from Tornado Alley and this year we had tornado activity in January. Who gives a crap if we also had one in January of 1412? Now we are having tornado strength wind every time we have a thunderstorm. Stop looking for reasons to accept that these things are normal. December 21st 2012 may not be the magical day that all life will cease to exist on this planet but those of us who are still here may not want to be here any longer. Like it or not all things must come to an end and that includes you and I. If you have a God it’s time to make things right and if you don’t then make things right with those you love. Stop being a jerk to those you don’t care about and live your last remaining days in peace.

Dan Holland July 29, 2012 at 2:06 pm

We are currently 10,000 years into a interglacial warming period. The previous interglacial warming period lasted 80,000 years. 125,000 thousand years ago the climate was warm enough to have corral reefs off the New England coast as evidenced by corral reefs buried under sediment. If the present interglacial warming period is like previous warming periods it is reasonable to expect the climate to continue to warm for many thousands of years. However, there will be many ups and downs in temperature with an overall trend of warming as occurred in previous interglacial warming periods. Any man made effect on global warming not provable, there are just to many variables. For example, CO2 from volcanoes above and below the seas,variations in earths orbit and solar output to name a few. The environmental extremists cite methane from cattle flatuience as a contributing factor in global warming. 125,000 years ago there were a lot of elephants around, mastodons and mammoths . I’ll but they could let one rip! Or maybe the Neanderthals were burning coal in their caves!

Marlo Lewis August 14, 2012 at 9:45 pm

Virgil, thanks for asking me to check Pat Michaels’s math. I think there was a typo in Pat’s article.

Pat wrote: “It takes about 37.4 gigatons of ice loss to raise the global sea level 0.1 millimeter—four hundredths of an inch.” As you correctly point out, if 37.4 gigatons raises global sea level by 0.04 inches, then a combined Greenland/Antarctica ice loss of 191 gigatons a year produces 0.2 inches of sea level rise in a year and 18 inches in 90 years.

But 0.1 millimeter is not 0.04 inches, it is 0.004 inches. See the conversion chart here http://calculator-converter.com/mm_to_inch_millimeters_to_inches_conversion.php. It shows that 1 millimeter (not 0.1 mm) = 0.039 inches. So Pat’s typo mislead you into thinking that the current contribution of Greenland/Antarctica ice loss to sea level rise is 10 times larger than it actually is.

Marlo Lewis August 15, 2012 at 1:24 am

Dave,

I am unaware of any scientific studies of sea-level rise in the Torres Strait. I find reports on the Internet about the plight of villagers living on Saibai Island. On Saibai, king tides repeatedly breach the low, crumbling sea wall built in the 1980s. See, for example, http://www.abc.net.au/news/2012-03-02/cohen-saibai-sinking-feeling/3865116.

During the past 30 years, the island reportedly lost about 200 meters of ground in front of the village. Sea water flooding damages roads, houses, the public school, and the cemetary; spills raw sewage into fresh water lagoons and coastal fishing areas; and produces brackish ponds that breed malaria mosquitoes. Not a pretty picture.

The same article notes that Saibai at its highest elevation is only 2 meters above sea level. That is hard to square with your recollection of sea levels rising at a rate of 1 meter-plus every year. The article also mentions that the “worst tidal surge” experienced on the island occurred in 1948, “and people were forced to leave.” That was three decades before global warming emerged as a public concern.

Three general points to keep in mind:

(1) Global sea levels and the rate of global sea-level rise cannot be determined from any one location. Local conditions — including land subsidence (sinking) — can dramatically affect the relative positions of the sea surface and the coast line. The following is an excerpt from Kolker, A. S., and S. Hameed. 2007. Meteorologically driven trends in sea level rise. Geophysical Research Letters, 34, L23616:

“Determining GSLR [global sea level rise] rates is complicated by non-tidal, year-to-year variability in local mean sea level that is one to two orders of magnitude greater than the long-term trend, potentially masking changes in the rate of rise. The cause of this variability is largely unknown, although it has been linked to storms, winds and floods, wind driven Rossby waves, shifts in major ocean currents such as the Gulf Stream, volcanically induced ocean heat content variations, and in the Pacific Ocean, the El Nino Southern Oscillation.”
Source: http://www.worldclimatereport.com/index.php/2008/01/04/lowering-sea-level-rise/

(2) Global sea level rise is measured in millimeters per year, not feet per year, and the rate of sea level rise is not accelerating (see, for example, http://www.co2science.org/articles/V15/N31/C1.php and http://www.co2science.org//articles/V10/N32/C1.php).

(3) If all the ice on Greenland melted, this would raise sea levels by 20 feet. The real issue, however, is how likely that is to occur, and over what time frame. The Arctic (which includes Greenland) was substantially warmer than it is today for millennia during the last interglacial period (http://www.worldclimatereport.com/index.php/2007/02/05/arctic-lessons-from-the-last-interglacial-polar-bears-survived/). The ice sheet did not disappear.

Ridley et al. 2005 (http://journals.ametsoc.org/doi/pdf/10.1175/JCLI3482.1), a study reviewed in the IPCC’s Fourth Assessment Report, estimates that CO2 levels would have to reach 1,000 parts per million (~2.5 x current levels) and stay there for 1,000 years to melt half of Greenland’s ice. Yes, it’s just a climate model projection. Nonetheless, even if the projection is way off, Al Gore’s scenario of a 20-foot wall of water sweeping the globe and displacing hundreds of millions of people in our lifetimes, or those of our children’s children, is science fiction.

Marlo Lewis August 15, 2012 at 10:52 am

Dale,

Assembling the “big picture” of bad weather on a planet as big as the Earth is more difficult than you may suppose.

One reason is that it is possible to define “extreme weather” in numerous ways (total rainfall for a year, heaviest rain in one day, number of days with more than 2 inches of rain, number of consecutive days, etc.). This means that reseachers can get almost any result they want.

Another reason is that the “big picture” is about climate CHANGE, and there are many more weather monitoring systems today than there were decades ago, especially in developing countries. This makes ‘then and now’ comparisons very difficult. More extreme events will be detected and recorded just by virtue of the increased density and spatial coverage of weather-tracking technology.

Finally, there is much more media coverage and instant communication about weather today than there was 30 years ago. We are surrounded by weather-related news and commentary. This enables us to ‘see and feel’ weather in more and more places we’ve never been.

You write: “In the past five years we have seen more weather related anomalies than we have seen in the past eighty years.” This is not the case with the respect to heat and drought in the United States, the country with best long-term temperature records. Weather in the 1930s was drier, hotter, and more variable than in any succeeding decade. See, for example: http://www.worldclimatereport.com/index.php/2012/07/13/the-heat-was-on-before-urbanization-and-greenhouse-gases/#more-547 and http://www.globalwarming.org/2012/08/03/john-christy-climate-data-maven/.

Since 2007, global hurricane activity has decreased dramatically whether measured in terms of frequency or accumulated energy (power): http://pielkeclimatesci.wordpress.com/2012/04/18/presentation-by-ryan-maue-titled-new-normal-historical-context-of-recent-global-tropical-cyclone-inactivity/.

As for tornadoes, 2011 was an active year, 2012 was not. As of Aug. 6, there were fewer tornadoes this year than in any year since 2005. In July, which was certainly a very hot month, there were fewer tornadoes than in any July in the 62-year record going back to 1950 (http://wattsupwiththat.com/2012/08/13/july-hottest-ever-but-u-s-tornado-count-lowest-since-1951-poisoned-weather-meme-falsified-by-nature/). Greenhouse theory does not project an increase in tornadoes, because, as Roy Spencer points out, tornadic thunderstorms do not require tropical-style warmth. In fact, tornadoes are almost unknown in the tropics. The apparent long-term increase in the total number of tornadoes over the past 60 years is an artifact of the data — a consequence of better weather-tracking technology (see reason two above). If we consider only strong-to-violent tornadoes (category F3 and above), which have been monitored for decades, the long-term trend is down: http://www.globalwarming.org/2011/05/02/tornadoes-blame-sins-of-emission/.

Another metric worth pondering: Global death and death rates associated with extreme weather decreased by 93% and 98%, respectively, since 1920. With respect to extreme weather, the world is becoming a safer place: http://www.jpands.org/vol14no4/goklany.pdf.

Finally, it is not true that “the only thing that people want to hear is that everything is ok.” Bad news is more exciting than good news. The media therefore craves bad news about the weather, because it helps boost sales and ratings. More importantly, the anti-fossil fuel lobby needs bad news about the weather to keep people in fear and, thus, willing to support wealth transfer schemes (like cap-and-trade) and the expansion of government control over the economy. H.L. Mencken said it best: “The whole aim of practical politics is to keep the populace alarmed (and hence clamorous to be led to safety) by menacing it with an endless series of hobgoblins, all of them imaginary.”

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