Earth's Mass Melting Problem and its Superior Effect on Water Temperature

Try to imagine having a glass of ice water on the hottest day of the year. The glass sweats in your hand as you try your best to remain hydrated in the heat. Before you’re able to finish your drink the ice has fully melted and the water is already starting to warm. Yuck.

Here’s the obvious point of the exercise. The amount of time it takes your drink to heat depends on the ambient temperature and the amount of ice that the glass contained. What may be equally obvious, but far less often considered, is that the same idea can exist on a much larger scale. Say, for example, the temperature of our lakes and oceans on Earth.

The temperature at ground level is rising. We’ve covered that from both sides of the global warming conversation on our blog before. What we haven’t talked about in detail is how that’s impacting the surrounding environment. Minnesota Public Radio brought the conversation to the forefront earlier this month when Dan Kraker of Duluth, MN talked about the temperature of Lake Superior throughout the 2016 season. In late August the average surface temperature for the entire lake nearly hit 69℉.

That’s a spring day in most places around the country, but, according to his report, this summer has ranked as the second hottest on record for the lake’s surface temperature, only beaten by the 2010 season. Kraker’s article explains this in more detail.

“In Lake Superior, researchers at the University of Minnesota Duluth have found that summer surface water temperatures have increased by 5 degrees over the past 30 years. That's twice as fast as the air temperature has increased, and some of the most rapid change observed on the planet.”

This takes us back to our initial exercise. You see, Lake Superior is like an Elephant. It never forgets. At least, that’s what Jay Austin, a physicist with the Large Lakes Observatory at UMD, alluded to when Kraker asked him about the subject.

"We use the term facetiously of course, but the lake has a memory. In that, summer water temperatures reflect what happened the previous winter."

In other words, the amount of ice cover that the lake generates in the winter impacts its temperature in the following season. That makes sense, sure, but maybe not often considered by the general public. NASA scientists, however, have been paying attention to ice levels for so long that the rapid melt they see along the arctic circle is no longer a surprise. So says Walt Meier, a sea ice scientist at NASA’s Goddard Space Flight Center, in a piece from Gizmodo.   

“A decade ago, this year’s sea ice extent would have set a new record low and by a fair amount. Now, we’re kind of used to these low levels of sea ice – it’s the new normal.”

In the video below you can see how ice coverage has changed throughout the year.

From a global standpoint, elevated temperatures means a melting of polar ice and rising sea levels. From a local level in Duluth, less ice means warmer water and better business, for now.

“Less ice cover could be a major boon for the Great Lakes shipping industry. Record ice cover in 2014 delayed the start of the shipping season and damaged ships trying to plow through thick ice sheets. In Lake Superior, warmer surface water could also result in a more productive fishery for species like salmon and brook trout, said Cory Goldsworthy, Lake Superior area fisheries supervisor for the Minnesota Department of Natural Resources.”

Kraker also reminds us that warmer water could also have a negative impact on the local fish. The rise in temperatures could make the waters more comfortable for non-native species like alewife that will feast on the young of other native species. The short term gain, just became a risk for long term loss.

Regardless of if you’re pulling for the short term gain or fearful for the long term loss, one thing in this conversation remains factual:  The ice has fully melted and the water is starting to warm.