Antarctic Polar Regions | The world of Antarctic Ice | The Ice Oceans

An iceberg of the size of Luxembourd ; the A25 affair

On 25 February 1995, a press release from the British Antarctic Survey (BAS) (1) announced to the entire world that two major events had just occurred along the east coast of the Antarctic Peninsula: on the one hand, the ice shelf that joined the coast and Ross Island by the Prince Gustav Strait had just smashed to smithereens. On the other, a gigantic iceberg (that came to be called A25) had been formed over an interval of two weeks by detaching itself from the Larsen Ice Shelf; measuring 78 kilometres long and 27 kilometres wide, with a surface area of 2,400km², the iceberg could be compared to the size of Luxembourg.

In 1995, an iceberg measuring 78 kilometres long and 27 kilometres wide, with a surface area of 2,400km², or the size of Luxembourg, detached itself from the Larsen Ice Shelf. An obvious sign of global warming?

In the press release, the glaciologist David Vaughan specified that the progressive and local warming of that part of the Antarctic had played a preponderant role in what had just taken place.

In parallel with this official announcement, there was testimony from men in the field who, quite clearly, were not treating this melting lightly. "For the first time in the world", declared Mike Thompson, the chief glaciologist of the British Antarctic Survey, after having flown over the coast in an aeroplane and been able to observe the devastation, "it is possible to navigate around Ross Island although this had always been linked to the continent by an ice shelf… I was on the other hand stupefied by the sight of this iceberg that had just detached itself from the Larsen Ice Shelf. In 25 years of fieldwork for BAS, I have never seen anything like it…"

A few weeks later, the Reuters Press Agency announced that the Argentinean glaciologist Rodolfo del Valle - he too working in the field - had wept when seeing the enormous crevasse of more than 70 kilometres long getting bigger before his naked eye. This was going to be the cause of the dislocation of the ice shelf…

The news spread like wildfire, in the world of glaciologists, in the institutes of climatology, and, naturally, in the international press. Presented by the BAS specialists as a sign of local warming, the information had become, in the space of a few weeks, the visible part of a veritable mini-catastrophe of planetary proportion, an evident indication of the warming of Planet Earth! The men from the BAS then tried to calm things down: but in the world of climatology also, one is on the lookout for little publicity coups to get oneself gently talked about, and the clarifications brought by the one or the other about the evidently local character of the event were not going to silence the commentaries.

Many scientists regretted in any case that the press seized upon the information in this way to make one more amalgam, to dramatise yet again the evolution of the world climate and to attribute to the events in the Antarctic an exaggerated importance that they simply did not have. "We live by the media and we die by the media; this is just as true for glaciologists as it is for Madonna…" one could read on the Internet of 01 March 1995 under the pen of an American glaciologist.

Beyond the debates that followed the announcement of these two events, this example contributed to a better dissemination of the problems relating to the melting of the ice. Once in a while does no harm, the scientific race had emerged from its customary ivory tower to express itself publicly and to try to make everybody understand what was really happening in the western part of the 6th continent. One single question, in fact, was spreading around the world : Were the creation of A25 and the dislocation of the Prince Gustav Ice Shelf evident signs of global warming, or were they not?

In scientific matters, answers are never simple.

  • First observation: the dislocation of ice shelves and the carving out of giant icebergs are not new phenomena in this western part of the Antarctic. In 1963, an iceberg of 110 kilometres by 70 was observed by satellite in the surrounds of the peninsula; it survived until 1970. The Müller Ice Shelf has been receding since 1974; the Wordie Ice Shelf dislocated itself in 1980 - both belonged to the west coast of the peninsula. In 1986, 13,000 km² of ice detached itself from the Filchner Ice Shelf (to the east of the Weddell Sea) carrying away both the abandoned Argentinean scientific station (Belgrano 1) and the Soviet summer base of Druzhnaya. In the same year, 11,000 km² of ice detached itself from the Larsen Ice Shelf. One year later, in October 1987, the B9 iceberg detached itself from the Ross Ice Shelf; it measured 160 kilometres over 40! One of the most monstrous icebergs ever seen. In short, in 50 years, 5 major-sized parts of ice shelves have separated themselves from the Antarctic Peninsula.
  • Second observation : the men from the BAS working at the Faraday meteorological station on the west coast of the peninsula noticed a small but constant increase in the temperature of the order of 0,056°C per annum. The result is evidently more spectacular when one goes back 50 years and observes that since 1945 the mercury in this part of the world has risen, in all, by 2.5°C. But when meteorologists extrapolate this rise to the scale of the continent as a whole, this produces a rise in temperature of only 1.5°C.
  • A final clarification: scientists have remarked that the most preoccupying phenomenon in the ice shelf dislocation was not their number, but the speed with which the splits were produced. In the A25 affair, less than three months had hardly gone by between the moment when the Prince Gustav Ice Shelf had seen its first crevasses begin to crack it and the day when it really disintegrated. In that, it merely followed the general tendency maintaining that the Antarctic ice shelves are dislocating themselves more quickly than before.

More generally, one can conclude by clarifying that the unexpected or sudden carving out of icebergs is not necessarily a sign of imbalance in the Antarctic ice environment. The Belgian scientists Tony Van Autenboer and Hugo Decleir were able, in effect, to observe (between 1967 and 1969, when they were working in collaboration with their colleagues from the South African Sanae base) the creation of giant icebergs coming from the dislocation of a peninsula of ice of more than 4,000km² of ice located 150 kilometres opposite the immense glacier, Jutulstraumen. If they had not been able to measure simultaneously the dimensions, the speed of seeping and the flow of this monster at the same time as the surface area and thickness of the ice shelves that it had produced between the peninsula and itself, they would doubtless have been asking themselves the same questions about the origin of this break as those that had just been raised on the subject of the A25 affair. But the results of their calculations indicated a quite different direction: that, entirely natural, of the mechanism of the ice and the laws of equilibrium. Two years of work in the glacier and on the bordering ice shelves had, in effect, shown that the peninsula in question had taken about a hundred years to be formed by the constant flow of its glacier and that, if it had been dislocated in a few months, it was because the volume of its ice had become too large for it to be able to continue to be integrated with the ice shelf to which it had been attached for a hundred years.


(1) The British Antarctic Survey (BAS) is a British research institute whose initial objectives were intended to conduct high level research programmes in Antarctica. These programmes had the dual goal of enabling England to play an influential role in the region and to give that country a not insignificant voice among the member countries of the Treaty of Washington. The studies conducted by the BAS concerned all aspects and all scientific disciplines; they took advantage of several permanent stations in the field to concentrate their efforts concerning at once the future of the region (the Antarctic) and the future of the world - global warming of the planet or the pollution of the oceans, for example.