In general, climate change is a term that refers to the significant transformations in global weather patterns over an extended period of time. It is now widely understood and accepted that the increased use of fossil fuels have been contributing to this for the last several decades. One of the most noticeable indicators of climate change is the decrease in Arctic ice, and this is becoming more apparent through satellite imagery. Consequently, scientists have recently discovered a significant reduction in the thickness of the ice cover in Alaska.
Satellite radar imagery from the European Space Agency (ESA) of the last few years has now revealed that the thickness of the ice in northern Alaskan lakes is declining during the winter months. A new study of the state’s North Slope examined the ice regimes of shallow lakes and found a substantial decrease of 22% in grounded ice, the type of ice that is frozen through to the lakebed. This amounts to an overall decrease of about 21 to 38 centimeters or about 8-14 inches.
While these amounts may seem trivial, even minor changes in the Alaskan ice cover could have a large impact on the region and the globe. Fluctuations in ice cover have the potential to disrupt local and regional climate, the availability of water for both commercial and residential use in the winter, and the dynamics of the underlying permafrost, the perpetually frozen soil found at high latitudes. Ice cover levels also affect the surrounding ecology because of how it changes the properties of the water.
The radar images that show this decrease come from the ESA’s ERS-1 and ERS-2 satellites. These radar instruments were able to take pictures even through cloud cover and in the dark to provide continuous images of the Earth’s surface. This is ideal for use over regions like Alaska because of its long periods of darkness and propensity for bad weather. The radar signals that bounced back helped scientists determine differences in the ice cover, more specifically whether the ice was grounded or floating with water underneath it.
The data collected from these satellites stunned scientists showing a dramatic decline in just 20 years. They also discovered that the greatest decrease happened during the late winter months of April and May. Scientists attribute the significant decline to changes in air temperatures and winter precipitation. Plans are in the works for more monitoring of the ice in northern Alaska during the upcoming Sentinel-1 mission.
Reference: Arctic lakes show climate on thin ice – European Space Agency