On the whole, the world’s greatest ice mass loss has come from Greenland, Antarctica, and especially the Arctic Ocean. The latter is best illustrated in this NASA animation,(click on "sea ice"), which traces arctic sea ice minimum going back through the satellite record, which began in 1979.
This loss of arctic sea ice was well predicted in earliest climate models. Again, as ice melts and thins, its white reflective surface is replaced by dark water. The dark water absorbs solar energy instead of reflecting it, accelerating warming and evaporation in the region.
Glacier ice mass loss is another red flag for mean global warming. Since I’ve shown you a significant exception to the rule of rapid glacier ice loss, let’s look at the overall picture, via an image from the European Space Agency.
In a just published study in Nature, an international group of multi-disciplinary scientists have used satellite imagery and direct field measurements to calculate the planetary losses of well over 9 trillion metric tons of glacial ice between 1961 and 2016. Mashable.com featured an article concerning this study, in which this ice mass is shown to be the equivalent of 27 billion 747s in weight, each one of which weighs about 775,000 pounds. This is not to undermine the significance of the regional exception in that major Greenland glacier, but it must be kept in mind that that glacier is an exception, and not at all a sign of a trend reversal globally.
Michael Zemp, director of the World Glacier Monitoring Service at the University of Zurich, stated the world is currently losing about 335 billion metric tons per year of glacial ice. (There are 2 trillion pounds of ice in 1 billion metric tons.) This is the equivalent of 3 times all the ice stored in the European Alps, annually.
In my own mind, I found I had been underestimating the contribution of glacial ice melt to sea level rises. About 30 percent of these rises is directly linked to glacial loss. Due to Alaska’s proximity to the fastest warming global region, the arctic, Alaska’s ice loss accounts for about a third of the total glacial ice mass reduction.
It should be noted sea level rises are not uniform around the globe. Some regions are experiencing lesser rises, and others observe more. Sea level rise along the U.S. East Coast is closer to 9 inches in the last century. Much of this higher rate of increase is due to ocean absorption of 90 percent of the planet’s additional warmth during this era from the atmosphere. The seas are largely a heat “sink,” or sponge. Water expands as it warms. Some other regions have less sea level rise due to cold pools and cold currents dominating.
This study shows only one global region has gained glacial ice mass between 1961 and 2016, and that is southwest Asia. However, southeast Asia has essentially canceled out that lone gain with ice mass loss of its own.
When one examines sea ice rather than glacial, the trend there is dramatic and irrefutable evidence of the mean warming climate. Here is data compiled by the Danish Meteorological Institute.
Projected sea level rises through the end of the century continue to be ominous at best. NASA is currently going with a more conservative estimate of 1 to 2 feet in that period of time. However, warming and sea level rise have been generally running above predicted rates. Worst-case scenarios put the rise at approaching 6 feet. A 6 foot rise would have disastrous consequences for sea coast locations, eclipsing the dangerous impacts of a 1-2 foot rise. Current sea level increases are already contributing to more astronomical tidal flooding in locations such as South Florida as well as worsened storm surges from tropical cyclones, along with coastal and island erosion.
One of the grislier impacts of shrinking glacier ice mass has become most evident on Mount Everest, as detailed in this recent Washington Post article.
I guess that takes climbing Mount Everest off my bucket list. Maybe I’ll settle for that big hill in Chestnut Ridge Park.