A five year research project by UK scientists, funded by the National Environment Research Council (Nerc), is investigating how increased algal growth on the Greenland ice sheet could increasing the speed with which the ice is melting.

Greenland is an unlikely name for a country which lies between the Arctic and Atlantic oceans, which appears much more white than green!  It's the least densely populated place on earth, with a population of around 56,500 people spread across an area of 2,166,086 square kilometres.  Over 80% of that area is covered by the Greenland ice sheet, which in places is up to 3km thick!
If all the ice contained in the Greenland ice sheet were to melt, global sea levels would rise by about 6 metres!  Currently, the meltwater from the Greenland ice sheet is adding about 1mm per year to global sea levels, so it's a slow process, but the scientists working on the 'Black and Bloom' project think the ice may start to melt more rapidly in the future.
With warmer conditions as a result of climate change, more algae has been able to grow on the ice sheet.  The algae tends to show up as grey or black patches on the ice.  White snow is good at reflecting the sun's heat, reflecting back around 90% of the heat, but dark areas on the surface of the ice where the algae is growing actually absorb the heat, reflecting back as little as 1% of the sun's heat in the darkest areas, causing the ice to melt more quickly.  So as it gets warmer, more algae grows, more heat is absorbed and more ice melts - and so on.
Satellite imagery has also shown that there has been a 15% reduction in cloud cover over Greenland in the last 20 years during the summer.    Fewer clouds could also be contributing to the increase in melt rates, but at the moment, the precise affects of reduced cloud cover are unknown.
This research is important because current climate change projections don't take into account the possibility of accelerated melting of the Greenland ice sheet.  Even small amounts of increased melting could start to affect low-lying coastal communities in the coming years.

Photo by NASA Goddard Space Flight Centre.