Even though many areas report severe heat and droughts, the Great Lakes continue to freeze as 88 percent of them are covered in ice. Temperatures recorded in these lakes have been a record high, something that has not been seen for almost two decades. It is believed that the North Atlantic currents are behind the sudden freezing of these fresh water bodies.
The Great Lakes is a name given to a series of interconnected freshwater lakes in the northeastern area of North America. It consists of individual lakes such as Lake Ontario, Lake Superior, Lake Erie, Lake Michigan and Lake Huron. Containing almost 21 percent of the world’s fresh water, together these lakes are the largest fresh water bodies on Earth. The measured total surface these lakes cover is approximately 94,250 square miles whereas the total volume is estimated to be 5,439 cubic miles.
These lakes freeze every year during the winters, but this year the lakes were 88 percent ice. The last time the world’s largest fresh water lakes froze to such an extent was in 1994. Ice cover over Lake Erie, Lake Superior and Lake Huron is even believed to be almost 100 percent.
The findings were revealed through NASA’s earth observing satellite Aqua. Aqua is designed to map the world’s water deposits such as lakes, oceans and seas. It was important to differentiate between ice, snow and clouds but was quite difficult as they were based on the same color scheme. The cameras hence used a combination of infrared, short-wave, red images and near infrared to differentiate between the them. From the pictures taken by Aqua it was easy to see that the surface of these Great Lakes was more than 88 percent covered in ice.
The idea behind using different wavelengths of light is that different features absorb and reflect light differently. This makes it easier to differentiate between water, ice and snow. Water hence appears deep blue, ice turns out to be pale blue, snow becomes blue-green in color and clouds look white or even blue-green.
Many expected January to be exceptionally cold but surprisingly it was the fourth warmest in recorded history. For example California faces a severe drought with little rain and Alaska is still dealing with its worst streak of heat.
It is expected that the freezing of these Great Lakes will have certain environmental effects on the surrounding areas. Guy Meadows the director of Michigan Technological University’s Great Lake research explained that this would potentially limit the lake-effect snow. Lake-effect snow is when snow is generated by cold air passing over warm bodies of water. Since a majority of the surface is ice warm water is unavailable. He went on to state that the ice is also causing a reduction in evaporation, although it might benefit the Great Lakes. Record low water levels were measured in the lakes and a reduction in evaporation might help preserve the water.
The freezing of these lakes might prove beneficial for many tourists as this would allow them to visit for the first time since 2009 the Apostle Island’s ice caves. Climatologists predict that global warming will make wet areas wetter and dry areas drier. As ice continues to cover the Great Lakes even though many areas report extreme heat, many concur that climate cannot be used as a basis to predict weather.
By Hammad Ali.