Ice-shelf Collapse Not Caused By Global Warming


Pine Island Glacier, or PIG for short, is one of the largest and fastest-moving masses of ice in Antarctica, accounting for around 10% of all the ice flowing out of the West Antarctic Ice Sheet into the ocean. A rift has formed in the shelf of floating ice where the PIG meets the sea, marked by a surface crack 60m (200ft) deep that runs for almost 30km (20 miles). When the rift becomes large enough a gigantic glacier will be formed that NASA researchers expect to cover about 880 sq km. The projected break away is expected at the end of the year or in early 2012.

As is de rigueur when such events occur, the proponents of manmade global warming will announce to all that this is a result of human CO2 emissions warming the planet. They will point out that, as the iceberg melts, it will inject millions of tons of freshwater into the southern ocean. Dust and rock fragments embedded in the glacial ice will alter the fragile marine environment when they fall into the ocean, possibly causing algal blooms. What's more, the massive chunk of ice may block animals trying to get to their traditional feeding grounds. Surely this is yet another natural catastrophe caused by man's poor stewardship of Earth. Or is it?

Despite what many alarmists will say, humans had nothing to do with the PIG's latest iceberg extravaganza. The events about to unfold on the bottom of the world are, in fact, all natural and have happened countless times before. You see, NASA researchers say this latest iceberg is part of a natural cycle seen every 10 years or so on this particular glacier.

“The last big calving event occurred in 2001 so in general people have been expecting something like this to happen fairly soon, and for us it is very exciting to see this while it is happening,” said Dr Michael Studinger, a scientist on NASA's IceBridge project. The IceBrige project is gathering data to fill the gap between NASA's now defunct Icesat laser altimeter spacecraft and the future Icesat-2 mission, which will hopefully launch later this decade.

But then, this is not news. Scientists have known about this natural cycle for years. As reported by Stanley Jacobs et al., in the May 2011 issue of Nature Geoscience: “In 1994, ocean measurements near Antarctica’s Pine Island Glacier showed that the ice shelf buttressing the glacier was melting rapidly. This melting was attributed to the presence of relatively warm, deep water on the Amundsen Sea continental shelf. Heat, salt and ice budgets along with ocean modelling provided steady-state calving and melting rates.”

Not so fast, say the alarmists. What about all those other glaciers that are being released and an abnormally high rate? While it is true that a number of huge icebergs were spawned from West Antarctica's Sulzberger Ice Shelf—a glacial formation that has remained stable for the past 46 years—it was not global warming's fault. Satellite photos show huge icebergs were created when the remains of the Japanese tsunami hit the Sulzberger Ice Shelf. Scientists estimate that 125 sq km of ice to broke off.

“The impact of the tsunami and its train of following dispersed waves... in combination with the ice-shelf and sea-ice conditions provided the fracture mechanism needed to trigger the first calving event from the ice shelf in 46 years,” reported Kelly Brunt, a cryosphere specialist from NASA's Goddard Space Flight Center. Brunt and colleagues were able to link the calving of icebergs from the Sulzberger Ice Shelf following the Tohoku Tsunami, which originated with an earthquake off the coast of Japan in March 2011. The finding, detailed in a paper published online in the Journal of Glaciology, marks the first direct observation of such a connection between tsunamis and icebergs. Before and after satellite photos are available from NASA here.

How long have gargantuan ice breakups been occurring? At least since the end of the last glacial period. According to research by Martin Jakobsson et al., images of the sea floor in Pine Island Bay reveal evidence that a massive ice-shelf break-up occurred before 12,000 years ago. It is also noteworthy because Jakobsson et al. propose that the icebergs produced during this collapse, and the associated sea-floor features, were strongly influenced by ocean tides. According to them, the catastrophic break-ups of the floating Larsen A and B ice shelves in 1995 and 2002—and the associated acceleration of glacial flow into these ice shelves—were just the latest in a long history of such events.

One last point, looking to the Northern Hemisphere and the Greenland ice sheet. The last interglacial period, the Eemian (130,000–115,000 yr ago), was characterized by warmer summer temperatures in the high latitudes of the Northern Hemisphere than in the current Holocene epoch. Back then the volume of the Greenland ice sheet was about 30–60% smaller than the present-day volume. Summer temperatures in the Arctic region were about 2–4ºK higher than today and was accompanied by sea-levels at least 4-6 meters (13-20 ft) above present.

The Eemian interglacial was the most recent time when Earth's climate was considerably warmer than now. As reported by van de Berg et al. in Nature Geoscience, the warmth was not caused by high concentrations of greenhouse gases, the claimed principal cause of anthropogenic climate change. Instead, the summertime warmth in the high northern latitudes was the result of the Eemian distribution of summer radiation between latitudes and seasons as determined by Earth's orbit. In short, temperatures were higher, sea-levels were higher and the CO2 levels lower last time around.

Here are the scientific facts, laid out for all to see. Yes, there are some very large blocks of ice being released by the Antarctic ice sheets, floating way as icebergs. This is what the ice has always done and what it will continue to do for the foreseeable future. In fact, there is good evidence that outbreaks of icebergs happen even during glacial periods (see Heinrich events).

So when the inevitable report comes on the evening news, that another giant iceberg has broken off from Antarctica and global warming is the cause, tell them to check the facts. Of course, checking facts is not something that the climate change alarmists are very good at, reality tends to get in the way of their theory.

Be safe, enjoy the interglacial and stay skeptical.


As does the author, I accept what the good scientists of NASA are saying here. Unlike the author I also think it's acceptable to accept what the good scientists of NASA are saying about 'anthropogenic global warming', it's happening and it's not scepticism to maintaint this position of denial based on picking and choosing your evidences so conveniently. This is the province of pseudo scientific wackos like the creationist movement.

It is irrational to believe

It is irrational to believe everything that is held by a majority of people in any field blindly. The article reported on is interesting in and of itself, but also because that it does not contain a blanket attribution to global warming. Note that I say global warming, not anthropogenic global warming. That is, global warming from what ever cause.

Given the history of past glacial periods it would not be exceptional or unexpected for global temperatures to rise by 2 to 4 degrees in the future, or for sea levels to rise 4 to 6 meters. What I am skeptical of is that humanity is the major cause of such change and that CO2 emissions are the mechanism. As a scientist I find those assertions are not justified by the data the climate change community has presented. We skeptics may be wrong, the majority of mainstream climate scientists may be wrong, but in the end it does not matter how many of us there are in either camp. What really matters is how nature works—and nature doesn't give a rat's ass about what we think.

Your argument here is nothing but an appeal to anonymous authority. As for climate change skepticism placing one in the same category as pseudo scientific wackos like creationists, that is an illogical assertion with no basis in fact. I might just as easily assert that people who make such arguments are scientifically illiterate, illogical morons with room temperature IQs—but then I would be just as wrong as you are. If you want people to respect your opinions you should really leave out the ad hominem attacks.

Skepticism Defined

As you said, Dr. Hoffman, many people really do not understand the true nature of skepticism. They believe skeptics to be anti-science when, in fact, they are the ones who ensure the integrity of the scientific method. I found an interesting site that talks about the nature of skepticism. For example: “The basic rules of science are that belief should be proportional to the quality of the evidence. And, belief must change as new evidence is found. As Feynman said, there is nothing that a scientist is completely certain of. There is no telling what I will have to unlearn tomorrow.”

Ice Stuff

Thanks for the lucid and clear discussion. Me thinks you are preaching to the choir. So am I at my philosophy of science blog. The problem with big things is the imagination and entertainment value. Lets face it facts are not checked because they are devoid of emotion. It is only when you can say "the size of xxxxx" that has value. If things can be related to something that has both perceived size and emotional value then the facts are irrelevant. Let's face it, 50 square miles of a city are worth at least 500 square miles of Kansas wheat fields. No penguins live in Kansas either.

Perhaps you know? What is it about caving glaciers that confuses people. It they are caving they are not growing. Shrinking glaciers are poor to nonexistent cavers. Oh I know. No caving no emotional, entertainment filled story. Got it. Ignorance always in advance of rationality.

Dennis Nikols, P. Geo.