Final answer:
The reflectivity of the Greenland ice sheet has decreased from 2000 to 2012 due to factors like ice melt revealing darker surfaces. These darker surfaces absorb more solar radiation, accelerating the ice melt and contributing to global warming and sea level rise.
Step-by-step explanation:
The reflectivity, or albedo, of the Greenland ice sheet is crucial for understanding its impact on climate change. From 2000 to 2012, this reflectivity has been affected by various factors, such as the melting of ice and snow which exposes darker surfaces beneath. These darker surfaces absorb more solar radiation, leading to further melting—a process known as a positive feedback loop. While the Arctic sea ice retreats and global surface temperatures increase, this accelerated ice melt contributes to rising sea levels and further climatic shifts.
Scientific data indicates that light-colored surfaces like snow and ice, which are highly reflective, are being replaced by darker surfaces due to melting. This results in increased solar absorption, as less radiation is reflected back into space. Consequently, as the Greenland ice sheet loses its reflectivity, the planet absorbs more heat, which in turn exacerbates global warming.