It’s hard to exist in today’s society without facing constant reminders of the declining state of the world’s environment. Between deforestation, habitat fragmentation, climate change, resource depletion, pollution, and other environmental degradation, our planet is constantly changing and is clearly in peril.
One of the most important and most polarizing issues is that of climate change. Whether you believe that climate change is caused by humans or not (we’ll return to this topic in a later post), its existence is undeniable:
- NASA has reported an average global temperature increase of 1.4°F since 1880
- The 10 hottest summers in 134 years of recorded data have all occurred within the last 20 years
- In the Arctic, the average summer sea ice extent has declined 13.4% per decade since 1980, and the 2012 sea ice extent was the lowest ever recorded
- Between the Antarctic and Greenland ice sheets, 421 billion metric tons of ice per year has been lost since 2002
Wait. How much ice are we losing every year? To put that in perspective, consider that the Great Pyramid of Giza is estimated to weigh nearly 6.5 million metric tons. We’re talking about losing 65 thousand pyramids worth of ice from these two ice sheets every year.
Perhaps one of the most alarming effects of climate change, at least to those with oceanfront property, is that of sea level rise. NASA reports that sea level has increased almost 8 inches (200 millimeters) since 1870 and is currently rising at 0.13 inches (3.42 millimeters) per year.
Think about that for a minute. The World Bank estimates that the life expectancy of the average American is 79 years. If sea level continues to rise at this rate, we would expect to see more than a 10¼ inch (270 millimeter) increase in sea level within a lifespan. And remember, we’re talking about a vertical change in sea level. When you visit your favorite, gently-sloping beach on your 79th birthday, it will look like a whole lot more than that (see image below). For all of you oceanfront property owners, maybe it’s time to think about moving to the mountains.
As if that wasn’t bad enough. Last month, a study suggested that sea level rise is about to get a whole lot faster. The authors demonstrated that a 3.6°F (2°C) increase in global ocean temperature will initiate a positive feedback loop – warmer oceans will cause increased ice sheet melting which, in turn, amplifies ocean warming. Another new study suggested that the disintegration of the Antarctic ice sheet has the potential to contribute over 3.3 feet (1 meter) to sea level rise by 2100 and over 49.2 feet (15 meters) by 2500. While these estimates of sea level rise still require fine-tuning, this could spell disaster for coastal communities around the world.
In February and March of 2002, the Larsen-B Ice Shelf located in the Weddell Sea collapsed. In total, an a area comparable to the state of Rhode Island broke away over the course of a few weeks. This video shows a series of satellite images taken between January and April of 2002, documenting the collapse of Larsen-B.
This is particularly alarming because, to date, much of the ice losses in West Antarctica and the southern Antarctic Peninsula have been partially counterbalanced by increased ice in East Antarctica. These studies, however, suggest that this balance won’t last for long.
Increased ice in East Antarctica – but I thought we’re losing ice? Overall, the effects of climate change are highly localized – climate is affected by the geography of the area. If you’ve ever visited Buffalo, New York in the winter, this might make sense. Large amounts of snow are produced due to lake effects. As cold air moves across the surface of warmer lake water, water vapor rises into the air and is deposited on the downwind shore. In Antarctica, we see much of the same effect, where changes in climate appear different across the continent.
In late 2015, NASA scientists suggested that ice sheets in East Antarctica are actually gaining ice. Many have taken this to mean that climate change is not affecting the Antarctic, but this isn’t necessarily accurate. The study attributed the increases in the East Antarctic Ice Sheet to snow accumulation. But let’s consider the cause of increased snow – warmer temperatures lead to increased evaporation – increased evaporation leads to more moisture in the air – more moisture in the air means more precipitation. Because of this relationship, the increases we see in East Antarctic ice are actually expected under climate change.
For more information about how climate change is affecting the East Antarctica Ice Sheet, check out the LiveScience article.
Added to that, there is clear evidence that the Arctic has been experiencing massive declines in ice – losing 13.4% every decade since 1981! And this month NASA confirmed that this year’s peak Arctic sea ice extent was a record low for the second year in a row since data collection began in 1979.
Unfortunately, these observations and projections of increased loss of sea ice have serious implications, suggesting that the rate of sea level rise we’re experiencing now will only increase in the future. Remember that 10 inches of vertical sea level rise in a lifetime? If that’s a low estimate, what will your favorite city look like? It might be time to invest in a snorkel.