Category: Before Our Eyes

From January 31 to March, 2002, scientists in airplanes, on research ships, and in front of NASA satellite imaging screens watched in amazement as the Antarctic Larsen B Ice Shelf, a 1,255 square mile mass of ice larger than the state of Rhode Island, collapsed completely in a period of just 35 days.

Ice shelves are large sheets of floating ice that form where continental glaciers slowly drain into the ocean. Research published in the journal Nature shows the Larsen B Ice Shelf has been stable for at least 10,000 years, with chunks breaking off at roughly the same rate they were replenished by the draining of the contributing glaciers. (For reference, the earliest human civilizations – Mesopotamia and so on – appeared about 6,000 years ago.) This balance of ice loss and replenishment, which had persisted for at least about twice the entire duration of human civilization, ended abruptly in 2002.

A 2014 paper published in the journal Science reported studies of the Larsen B grounding zone (the zone where the floating ice shelf had been connected to the coastal bedrock) showing it had been stable before the collapse. This indicates the collapse was driven by unusually high surface temperatures, exceeding the highest surface temperatures that have occurred for at least the past 10,000 years. Ponds of melt water formed on the surface of the ice shelf (you can see them in the first satellite image above). Those filled small cracks on the surface of the ice, and the weight of the water then drove the cracks through the full thickness of the shelf. Read more here.

Like the Arctic in the Northern Hemisphere, Antarctica has undergone a surface temperature rise faster than the global average, about 0.5 degrees Celsius per decade, since at least the late 1940’s. The 2002 event was a dramatic illustration that large, previously stable ice shelves can be highly sensitive to surface temperature changes.

Since ice shelves are already floating on the ocean, the collapse of one does not itself contribute very significantly to sea level rise. However, ice shelves slow down the flow of continental glaciers into the sea, and that ice contributes directly to sea level rise. In fact, a detailed 2004 study of five glaciers previously buttressed by the Larsen B Ice Shelf showed they had sped up by factors between 2 and 8 by the end of 2003, contributing an additional 6.5 cubic miles per year of water to the oceans. Potential sea level rise from a complete melting of this region of Antarctica, the Antarctic Peninsula, is estimated at 0.46 meters. Potential sea level rise from a combined melting of the Greenland and Western Antarctic ice sheets similar to melting that occurred in the distant past would cause a sea level rise of 10 meters, flooding about 25% of the current U.S. population. To read more, see this U.S. Geological Survey fact sheet.

As for the Larsen B Ice Shelf, a 2015 NASA study indicates the surviving portion will disintegrate within a few years (see video below).

#AskYourDenierIfTheyveSeenThis

See more changes happening Before Our Eyes.

Sad about this post? Consider doing something about it. It’ll cheer you up!

On August 16, 2016, the registered voters of Shishmaref, AK voted 89-78 to move their town.

Shishmaref, AK is a town of about 650 people located on an Alaskan barrier island 30 miles south of the Arctic Circle. Archaeological evidence shows people have been living there since at least the 1600’s. Elder residents of Shishmaref recall playing sports on the wide, sandy beaches that surrounded the town in summer:

Lately, not so much.

Since the 1950’s, the town has been rapidly disappearing into the encroaching Arctic Ocean as it faces a “triple threat” of Global Climate Change effects:

• The surrounding sea ice barrier melts earlier in the spring and freezes later in the fall than it used to, leaving the island vulnerable to erosion by violent early winter and spring storms.
• Arctic sea ice decline, averaging about 3% per year, has opened up vast stretches of the Arctic Ocean that used to be frozen, enabling the growth of large waves in the Arctic that batter the coastline.
• The permafrost on which the town is built has been melting, transforming from a hard, rock-like substance into a mushy sand that is easily eroded.

This is not the first time the residents of Shishmaref have voted to move their town; similar votes passed in 1973 and 2002. The earlier efforts involved substantial study but were unsuccessful, not least of all because of the cost. A U.S. Army Corps of Engineers study in 2004 estimated it would cost $179 million to move the town to the Alaska mainland. At about $275,000 per resident, this seems like a reasonable cost if you consider the re-construction of housing for each resident as well as all the public services (schools, medical, utilities, roads, etc.) they currently have. But their requests for state and federal funds for a relocation have, so far, been unsuccessful. Instead, the Army Corps of Engineers helped the residents of Shishmaref build a seawall of boulders, on the shore of their island, to buy them about 15 years to think.

You can read more facts and history about Shishmaref if you want (here, here, here, here, here, and here, for example). Or, you can watch the 5-minute video at the end of this post. Before I lose your attention, I’d like to move on to a couple important questions brought up by Shishmaref. Because Shishmaref is a canary in our coal mine (double meaning intended.) Temperatures in Alaska have increased by 3.4 degrees Fahrenheit over the past 50 years, faster than the rest of the U.S. Over 30 other Alaskan towns face “imminent threat of destruction.” So if you live near a coast, the plight of Shishmaref, and towns like it, is a foreshadowing one.

The questions of adaptability and cost

Many think we can “simply adapt” to Global Climate Change. Shishmaref has a population of 650 and has been seeking funds to relocate since the 1970s. If we consider this tiny town as a test case for adaptability, the results have not been encouraging. With nearly 50 years of effort, the citizens of Shishmaref have managed to attract funding to build a seawall of boulders that everyone recognizes as only a temporary measure. It’s tempting to think these are distant people who have chosen to live in a “stupid place.” This is demonstrably not the case. People have been living in Shishmaref for 500 years, with no problems until around 1950. They are U.S citizens, residents of the state of Alaska. As such, their challenges have been studied by the U.S. Army Corps of Engineers. The result, so far, has been a boulder seawall as a temporary measure.

Now consider, for example, the New Orleans metropolitan area, a population of 1.3 million people living 1-2 feet below the current sea level. What will be the cost of protecting that population from future rising sea levels? Who will pay for it? And what about all the other coastal cities of the U.S.? According to a U.S. Geological Survey report, 50% of the U.S. coast is at a “high” or “very high” risk of impacts due to sea level rise. According to the National Oceanic and Atmospheric Administration, 16.4 million Americans live in the coastal flood plain (this figure is referenced here, although it has disappeared from the NOAA website). Think about this, when you hear any politician talk about the costs of switching to sustainable energy sources. Or, the purported economic advantages (jobs) associated with a new oil pipeline. Which is more expensive? Solar panels now, or seawalls and relocations later?

The question of morality

Shishmaref is emblematic of how we are engaged in a global tragedy of the commons. The folks of Shishmaref have contributed insignificantly to Global Climate Change. The median family income is less than $30,000 and most families there feed themselves based on subsistence hunting, fishing, and berry-picking, as they have for centuries. Gasoline arrives there by barge once a year in the summer, costs upwards of $6 a gallon, and is rationed by the populace when it runs out before the next annual shipment. When was the last time your hometown rationed gasoline? Yet, they are bearing the direct costs of climate change inflicted by the rest of us. Many observers think they will not, ultimately, be successful in relocating their town. Rather, they will simply disperse. They will eat the financial loss of their homes and lose their shared culture developed over centuries of living in that place. Even their departure will be tough; the only way out is by boat or plane, and the flight to Nome costs $400.

And this is how Global Climate Change will initially be paid for, if we don’t stop it. It will be paid for, at the start, by the poorest and most vulnerable people. The people who can’t easily move, or fund seawalls. So when we think about the costs of moving to more sustainable energy sources, we need to understand there are substantial moral considerations. Can we pay a little bit more per mile to drive our cars, for a time? Or should we rather consign other folks to a future of economic oblivion? (and later, our own children and grandchildren?)

#AskYourDenierIfTheyveSeenThis

See more changes happening Before Our Eyes.

Sad about this post? Consider doing something about it. It’ll cheer you up!