Having lived in Houston for over 25 years, I've been incredibly fascinated, and somewhat disturbed, by the change in our local climate for the past 5 years. We've had over 80 degree fahrenheit winters in multiple years, and this year; one of the largest natural disasters in our city's history in Hurricane Harvey. The effects of climate change have increasingly impacted Houston in a negative context, and many scientists have attributed the cause of these effects to warmer waters and the deteriorating polar ice cap. When investigating further, what piqued my curiosity was the gradual change happening at the world's end.
This simple graphic displays how sea ice reflects incoming solar radiation, sending it back into space and keeping our oceans cooler by reducing incoming heat
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At the opposite ends of the Earth, the polar regions of our planet are blanketed by millions of square kilometers of sea ice, which covers roughly 7% of the Earth's Surface, and 12% of our oceans. Sea ice floats directly over salt water due to it's lower density and is formed when the top layer of water cools to a freezing point. While one of it's primary purposes is to help manage the freshwater/saltwater balance of the ocean, sea ice also operates as an important reflection method for incoming solar radiation.
By having a lighter color, sea ice has incredibly high albedo (which I first thought was a dance), which is the measure of a surface's reflectivity. While darker objects tend to absorb wavelengths of light, like wearing a black shirt on a hot day, lighter colors will absorb less solar radiation and, instead, reflect a larger percentage. Due to its ability to effectively reflect up to 70% of the incoming energy, sea ice helps keep the planet's temperature cold (much like how snow keeps your favorite ski resort cold on a cloud-less day).
NASA's time lapse video that recorded the changes of the Arctic Sea Ice from 1984-2016
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Since the 1970s, about 1 million square miles of sea ice has been lost. In the 70s ski days would have been more abundant and one may not be sweating from the heat in Houston - in December. With greenhouse gases, specifically carbon dioxide, deteriorating the atmosphere - we have seen an increase in solar radiation hitting the surface and melting the sea ice at an accelerated rate. As stated by NASA Scientist Walt Meier, “There was a lot of open ocean water and we saw periods of very slow ice growth in late October and into November, because the water had a lot of accumulated heat that had to be dissipated before ice could grow. The ice formation got a late start and everything lagged behind – it was hard for the sea ice cover to catch up.”
If the amount of sea ice continues to diminish over time, that would mean warmer climates and oceans throughout the year. This includes fewer snow days, hotter winters, and deadlier natural disasters like hurricanes (which strengthen in warmer water). As we continue to pour greenhouse gases into our atmosphere and ignore the signs, our planet will primarily suffer along with humanity.
Differences from solar radiation reflection from 1980 to 2010.
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As I continue on my path to climate education, I will continue to write more on the subject on climate change and the effects it has on local ecosystems and at the global scale. Topics that also seem interesting are how scientists are starting to create artificial means of maintaining certain aspects of climate change, and Elon Musk's mission to create a electric-powered world. In case you missed my prior post, check out how global warming is decreasing our ocean's oxygen levels.
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