Sailing in the Southern Ocean (3): Is there more ice or is it that detection has improved?
All scientific evidence points to a direct relationship between an acceleration of the melting of the ice in Antarctic and climate change. However, there is still a lack of data to be able to effectively evaluate the danger of ice breaking off into the ocean and whether the ice is moving further north, up into relatively warm latitudes where it was previously difficult to find. There is also the fact that satellite ice detection systems show the presence of ice along the course of round the world regattas. Is there are relationship between the increase in the amount of ice being detected and the increase in the amount of floating ice itself? There isn't enough climate or scientific data to back this up and now it looks like yachtsmen and women racing through the Southern Ocean are likely to be important scientific agents in the quest for data.
The first part of the debate on Sailing in the Southern Ocean: Ice Gates and Climate Change which was held on the 5th of February at the Barcelona World Race Interpretation Centre, centred on the relationship between climate change and the presence of ice in the southernmost oceans of the planet. This is the third article in a series based on the round table discussion which brought together Jorge Luis Valdés, the Head of Ocean Sciences at the UNESCO Intergovernmental Oceanographic Commission, navigator Joan Vila and meteorologist Marcel Van Triest, along with members of the sailing press. [See videos of the entire debate]
The detection of icebergs using satellite technology was the motive behind the institution of “ice gates” to limit the descent of sailors taking part in round the world events such as the Vendée Globe and the Barcelona World Race into treacherous waters. There has also been tangible scientific evidence collected over the past few years to suggest that climate change is having a marked effect on the polar ice caps. Speaking on the subject of round the world regattas Joan Vila hit on a key point: “We don't know if there is currently more ice, or if it is just that now we are able to detect it”. Marcel Van Triest backed up Joan's opinion and added: “We don't have enough climate data available to be able to evaluate whether the ice is now climbing further north. It seems evident that more ice is melting, but to what degree the ice is moving into warmer waters? Well, we can't be sure. It's also worth bearing in mind that we have only been racing around the world for the past 30 years or so, so it's not really long enough to make any significant comparisons”.
Although there is still no data to directly link global warming to the increase in ice along the route sailed by round the world sailors through the Southern Hemisphere, it is obvious that the Antarctic is thawing at an increasingly accelerated rate and huge masses of ice break off and are adrift in the southern oceans. Jorge Luis Valdés pointed this out during a contribution at the beginning of the debate and also in an interview published on our website [see interview and see video of contribution]. The Spanish oceanographer said: “For now glaciologists are resisting making any explicit connection between ice breaking off in the Antarctic and the debate on climate change, but there's no doubt that it's likely. Scientifically more observation is needed to highlight whether the frequency is changing and if so, why?”.
Tangible evidence of change
The Director of Ocean Science at the UNESCO IOC brought some solid data with him to show clearly what was happening. Some data spoke for itself, underlining the severity of the situation, such as the fact that the Antarctic has warmed up by roughly 3ºC over the past 50 years and that the increase in temperature has also been the cause of the collapse of various sheets of ice, such as the Larsen B, which broke off in March 2002, releasing 500 tonnes of ice into the sea. Valdés gave a global perspective on these phenomena: “It's true that this type of glacier experiences a cyclical natural effect whereby the floating areas increase until an iceberg breaks off, so ice breaking off into the sea is a normal process for Antarctic glaciers. However, under the effect of prolonged global warming the frequency and magnitude may increase, causing a greater contribution to the increase in sea levels and posing a greater risk to sailors”.
The photographs and images obtained by satellite ice detection technology shown by Marcel Van Triest were also very impressive. In particular the photographs showing the evolution of the giant B-15 iceberg and it's largest fragments. Marcel showed screens with the results from detection services, results he had shared live with Joan Vila and Loïck Peyron during their passage through the Southern Ocean on the maxi-trimaran Banque Populaire V during the last Jules Verne Trophy. The photos show the spectacular fragmentation of the ice giant and how it affected the route of the multihull as it traversed the South Pacific. Marcel also showed some impressive photos of the 'explosion' of the B-15 J (one of the fragments of the famous B-15), a phenomenon concerned with the internal tension of the crystalline structure of the ice, which scientists have been studying (see photos).
A necessary collaboration area
The debate highlighted the singular nature of the round the world regatta course and the value the boats and their crews can offer to the issue of climate change by acting as sensors of numerous variables which are difficult to obtain in such faraway waters, such as salinity and temperature. It was also shown that detection technologies applied to increase safety in these regattas can, and have contributed important and until now unknown data on the evolution of ice masses in the Southern Ocean.
The problem of floating ice is complex and its melting depends on many different factors such as water temperature and salinity, but also on the force of the swell, as the movement of the water surrounding the ice is a factor which accelerates its disintegration (like the case of the ice cube which melts faster in a glass which is shaken...). There is still a long road ahead for scientists in this field, as Jorge Luis Valdés pointed out and the sport of sailing can provide some very valuable data: “The fact that all of the boats taking part in the next edition will be fitted with sensors for salinity and sea temperature will give us a bi-dimensional view of these parameters in a region about which we know very little. Along with the 'zero emissions' objective for the Barcelona World Race this is very important and sets out the path to follow for the future in terms of the relationship between sport and science. We all have to progress together and in doing so raise awareness of the issues”.