The Weekly Beaker: Arctic ice and snow loss signals points to rising oceans and unstable climate
Published: Monday, October 22, 2012
Updated: Monday, October 22, 2012 21:10
In mid-September, scientists announced that Arctic sea ice has reached its lowest point since measurements were first taken in 1979.
In a natural cycle that follows the seasons, sea ice freezes in the winter and partly melts away in the summer. But since satellite records first began in 1979, the amount of ice left at the end of each melt season has declined by 12 percent every decade. It reached its nadir this September at 3.41 million square kilometers. The previous low was in 2007 at 4.17 million square kilometers. The current number is also 3.29 million square kilometers less than the average minimum between 1979 and 2000. This represents a dramatic Arctic climate change in a very small time frame.
Melting of ice both in the Arctic and in Antarctica will lead to rising coastlines all over the world, threatening major cities, towns and their inhabitants. This puts the approximately 80 percent of the world’s population living within 62 miles of the coast at a particular risk. The Maldives, an island nation off the coast of India, has a maximum altitude of 1.5 meters. They obviously take the threat of sea level rise quite seriously. They’ve invested heavily in renewable energy and according to their President, Mohammed Nasheed, they plan to be completely carbon neutral by 2020.
Sadly, the Maldives and other small island nations are contributing negligibly to climate change but are and will continue to suffer the consequences most severely. Samoa is an island in the central South Pacific whose shoreline has retreated 160 feet in some places, according to a World Wildlife Fund report. Tuvalu, a neighbor, has had its groundwater become undrinkable due to encroaching salt water.
Dr. Robin Bell of Columbia University’s Earth Institute has this to say: “If the West Antarctic ice sheet were to disappear, sea level would rise almost 19 feet; the ice in the Greenland ice sheet could add 24 feet to that; and the East Antarctic ice sheet could add yet another 170 feet to the level of the world’s oceans: more than 213 feet in all.” She notes that the Statue of Liberty is only 151 feet tall. Though this increase would take many years, the process has already begun.
The loss of sea ice is paralleled by a related issue—the rapid loss of Arctic snow. Like sea ice, snow in the far north begins to melt away in the spring when temperatures rise. But a recent study by researchers at Environment Canada shows that the amount of Arctic snow is melting at an even faster rate than that of sea ice, at about 18 percent every decade.
Snowmelt timing is an important environmental variable—it determines when water flows back into rivers for the warmer months. The altered snowmelt pattern affects the waterways that fish rely on for spawning. It also accelerates the melting of the permafrost, a layer of frozen soil which traps large quantities of carbon during the winter. As you can imagine, an earlier permafrost melt releases the carbon into the atmosphere, which traps heat. An earlier drying out of the soil in springtime can also lead to more and larger forest fires, a trend that received plenty of attention this year with the raging wildfires in Colorado, Idaho, Washington and Montana.
When both ice and snow melt, they reveal their underlying, darker surfaces: the ocean and forests and soil. Whereas the white of ice and snow reflects sunlight and heat back into space, the darker colors underneath absorb light, resulting in more heat remaining within our atmosphere. As more heat accumulates, more ice and snow melt in a daunting positive feedback loop.
The urgency and the horror of such facts are highlighted in one of the all-time popular Rolling Stone articles by leading climate activist Bill McKibben: “June broke or tied 3,215 high-temperature records across the United States. That followed the warmest May on record for the Northern Hemisphere – the 327th consecutive month in which the temperature of the entire globe exceeded the 20th-century average, the odds of which occurring by simple chance were 3.7 x 1099, a number considerably larger than the number of stars in the universe.” And there are a lot of stars out there.