I read an article in the science journal Eos, Transactions of the American Geophysical Union today about how well sea ice reflects the sunlight. It was summarizing a paper that appeared in Geophysical Research Letters. What these researchers found was there was that old and new sea ice reflected pretty much the same amount of sunlight during the winter months, but there was a big difference in the summer months. In fact, they found that areas with seasonal sea ice (ice that melts in the summer) will absorb 40% more energy than areas covered with multi-year ice.
Since the area covered with multi-year ice is getting smaller every year and being replaced with seasonal sea ice, this is a significant finding. As the ice melts at a greater rate and gets thinner and thinner, we will get a positive feedback where even more ice will melt. This will result in changes in the currents and weather systems in the arctic region and that will affect the rest of the world, including us. Just exactly what those changes, and resulting effects, will be is not entirely clear, so it will be increasingly important for us to study and document these changes in coming years.