Jun. 23, 2017

Beyond Sea Level Changes

Polar Ice

According to NASA, Antarctica and the Arctic are two very different environments: the former is a continent surrounded by ocean, the latter is ocean enclosed by land. As a result, sea ice behaves very differently in the two regions. While the Antarctic sea ice yearly wintertime maximum extent hit record highs from 2012 to 2014 before returning to average levels in 2015, both the Arctic wintertime maximum and its summer minimum extent have been in a sharp decline for the past decades. Studies show that globally, the decreases in Arctic sea ice far exceed the increases in Antarctic sea ice. Since the late 1970s, the Arctic has lost an average of 20,800 square miles of ice a year; the Antarctic has gained an average of 7,300 square miles. It is predicted that Arctic sea ice may disappear in the summer by 2040.

Sea ice is different than land ice and the increase in sea ice in the Antarctic could be due to changing wind patterns and circulating warm air over the peninsula, while sweeping cold air from the Antarctic continent over the Ross Sea. Melting ice on the edges of the Antarctic continent could be leading to more fresh, just-above-freezing water, which makes refreezing into sea ice easier. Scientists are working on understanding why the Antarctic sea ice is increasing. But the land ice is receding and currently a piece of the Antarctic ice shelf as large as Delaware (1,900 sq miles) is in the process of breaking away.

So why should we worry about the melting ice thousands of miles away? Increased sea levels are a major concern, but the concerns about changes in high latitudes are much bigger than rising sea levels. The higher latitudes are the air conditioning system for the planet. Thawing ice, which is cold fresh water, changes water density and could affect major ocean currents that dissipate heat throughout the ocean and atmospheric systems. Also, the dense cold air above the Arctic creates high pressure systems that steer the jet stream. As the Arctic warms, the jet stream dips down, bringing severe winter weather to mid-latitudes called polar vortex effects.

As the ice melts, the effects are magnified due to albedo effects. Albedo is a measure of how reflective a surface is, and the Earth's albedo influences the climate by determining how much sunlight is absorbed or reflected. Bright ice reflects sunlight, dark ocean waters absorb it. As the ice melts, more heat is absorbed instead of reflected- like the difference between sitting in a white or dark blue car on a hot summer day.

There is also the issue of an increase in methane (a powerful greenhouse gas) from melting permafrost—ground that is usually frozen most of the year— which I have discussed in previous posts under methane and also The Great Dying.

Yes, this is a very complex system. All of these variables added together could have an exponential effect on rates of change in major earth systems. And the complexity speaks to the issue of the uninformed discussing climate change. Example: Rick Perry, currently Secretary of Energy, recently made statements doubting man’s involvement in climate change. Perhaps he should read some of the scientific research produced by his own alma mater, Texas A&M University. At any rate, the polar systems are intricate, multifaceted and can have a major impact on the oceans, the atmosphere- the entire planet.