A study revealed that there has been a decrease in the amount of sunlight being reflected back into space due to shrinking ice and snow cover in the Northern Hemisphere, which was previously underestimated. Satellite data from 1979 to 2008 showed that Arctic sea ice, glaciers, winter snow, and Greenland's ice were reflecting less energy back to space. This decrease in reflection is causing the Earth to absorb more heat, as ground and water are exposed instead of being covered by white ice and snow. The study estimated that ice and snow in the Northern Hemisphere are now reflecting an average of 3.3 watts per square meter of solar energy back to the upper atmosphere, a reduction of 0.45 watt per square meter since the late 1970s. Mark Flanner, an assistant professor at the University of Michigan and lead author of the study, explained that this reduction in cooling effect is causing the planet to absorb more solar energy. He stated that the decrease in solar energy reflected due to warming is more significant than what current climate models suggest, as indicated by a group of researchers based in the US and reported in the journal Nature Geoscience on Sunday. He emphasized that the cryosphere is reacting more sensitively to, and playing a more significant role in, driving climate change than previously believed. With more ground and water being exposed to sunlight, the heat absorbed accelerates the melting of nearby snow and ice. The reduction in Arctic sea ice over the past few decades has been attributed primarily to greenhouse gas emissions from human activities such as burning fossil fuels. Numerous studies predict that Arctic sea ice could disappear in summers later in this century, posing a threat to indigenous hunting cultures and wildlife like polar bears, while also contributing to global climate change. Flanner stated that drawing conclusions about the future rate of melting, such as Arctic sea ice, from the study's 30 years of data was not possible. He emphasized that climate is influenced by many factors, with the reflectivity of snow and ice being just one. Other factors to consider include the presence of clouds, which can reflect sunlight, and an increase in water vapor, which can trap heat in the atmosphere. The study found that for every degree Celsius rise in temperature, there would be a decrease in solar energy reflected out to space from the Northern Hemisphere's snow and ice. In the last thirty years, temperatures in the Northern Hemisphere have increased by approximately 0.75 degrees Celsius. The study did not examine the Southern Hemisphere, where Antarctica has more ice but is colder and shows less evidence of warming. Flanner stated that on a worldwide level, the Earth absorbs solar energy at a rate of around 240 watts per square meter annually. Without the Northern Hemisphere's cryosphere, the planet would be darker and absorb an extra 3.3 watts.