April 5, 2011 | 4
I do not consider myself to be an explorer and I have never had the desire to walk to the North Pole. I always compete with the cat to be in the warmest spot in the house. I take a hot water bottle to bed in the summer and I do not like to be cold. So why am I here at the Catlin Ice Base, living on the sea ice, enduring daytime temperatures of -37oC, and sleeping in an unheated tent?
The answer is curiosity. After my first Arctic field trip in 2004 I was left with many unanswered questions about Arctic processes. It is the burning need to answer these questions and satisfy my interest that has brought me to the high Arctic in the early spring.
Here’s the science bit: since we began long term and large scale observations of the Arctic via satellites in the late 1970’s there has been a consistent decline in the summertime sea ice extent. This gradual decline has become a rapid descent in the last few decades.
At the end of summer in 2010 the sea ice covered only 4.60 million km2, the third lowest extent since records began in 1979. Less than 15% of all the sea ice in the Arctic is more than five years old compared with 50 to 60% in the 1980’s.
The sea ice acts as an insulating barrier between the atmosphere and the ocean. One of the most important jobs of sea ice is to reflect sunlight, preventing the sun’s rays from entering the water and causing heating. With less sea ice the darker water underneath is revealed and the sun’s energy warms the surface water causing heating and more sea ice melt. The continued melting of sea ice has significant impacts on those that live and hunt on the ice, including the iconic polar bears, walruses, seals and local people.
Impacts of a changing Arctic could also be felt across the globe. The amount of freshwater entering the Arctic from sea ice and glacier melt as well as from rivers is increasing. The concern is that this fresh water could affect global oceanic circulation by slowing down the sinking of cold salty Arctic water that drives major ocean currents bringing warm water northwards and cold water southwards.
My interest is in a very small part of this puzzle: why is the sea ice melting faster than we have predicted? One reason could be that the water in the Arctic is trapping more solar energy in the top 10 meters than we have accounted for, the net result of heating in this upper part of the water column is melting of sea ice.
From my previous observations in the Chukchi Sea, and other investigations across the Arctic Ocean we know that material produced from the degradation of plant matter called colored dissolved organic material is present in high quantities during the spring time. You can think of this material as oceanic tea: it is produced from dead plants just like your breakfast teabags.
The reason this "tea" is so interesting is that it can dominate the absorption of solar energy and trap up to 80% of this energy in the top few meters of the water column where it is in contact with the floating sea ice.
During my time here I will collect numerous sea ice cores and water samples to try to capture the process of this material being produced, to identify the ultimate source, the amount of sunlight it absorbs and how long it stays in the water column for. It is my hope that the data collected here will tell us more about the light absorbing compounds present in the early spring and allows me to pass this information on to the Arctic modelers who can calculate how important this oceanic tea is to the overall heating budget and sea ice melt.
This, and the outstanding beauty of the Arctic, is the reason that my heat-loving self is prepared to stand the cold for six long weeks at the Catlin Ice Base.
Photo credits: The Catlin Arctic Survey, Copyright Martin Harley.
Editor’s Note: The Catlin Arctic Survey is a unique collaboration among polar explorers and scientists to gather data on the impacts of climate and environmental change in the Arctic.
This 10-week international scientific expedition will travel to the farthest reaches of the Arctic to research the impact of melting ice caps on the world’s oceans and weather systems. In recent years, the surface area of Arctic ice has declined to levels that were not expected until 2070. The Catlin Arctic team will seek to understand how climate and environmental changes affect ocean currents, which have a major impact on weather patterns throughout North America. Scientists are predicting that climate-related changes in the way that ocean currents circulate could result in a dramatic increase in the frequency and intensity of storms and cause extensive flooding, coastal erosion and damage to crops, homes and cities across the U.S. and around the world. The scientific team will be based at a unique research station located on sea ice in the Canadian Arctic shelf.
Simultaneously, a team of polar explorers will undertake two separate Arctic missions: the first across the Prince Gustav Adolf Sea, and the second from the North Geographic Pole toward Greenland.
Victoria Hill is research professor of ocean, earth and atmospheric sciences at Old Dominion University, Norfolk, Va.