This year has almost ended, with an important episode in New Zealand's political history unremembered. Forty years ago the government sent two frigates - first the Otago and then the Canterbury - to the Pacific atoll of Mururoa to formally protest against France's testing of nuclear weapons in the atmosphere.

The country was pervaded by concern that the testing posed serious risks of long term pollution of the air and the oceans. Strontium 90 had been found in cows' milk.

In November that year - 1973 - after 36 atmospheric tests, France told the United Nations it intended to move its test programme underground.

New Zealand rightfully felt a jubilant sense of achievement.

The frigates were not the only vessels expressing the country's concern. Three yachts, Spirit of Peace, Fri and the Vega also sailed to the French islands. They were watched with intense interest by more than the French navy.

Photographs taken by Aucklander Anna Horne on the Vega of French sailors boarding the boat and assaulting its Canadian skipper, David McTaggart, were shown around the world.

The later corollary to these actions was the bombing by French commandos of the Greenpeace ship the Rainbow Warrior at Princes Wharf in July 1985.

Last month, the veteran Vega set out on another voyage, with five other yachts, to encounter the oil exploration vessel Noble Bob Douglas 100km off the coast of Raglan. The flotilla's return on December 1 was greeted at Princes Wharf by about 300 supporters.

While the Government's attitude to the protest may be the opposite to that of Norman Kirk's Labour government in 1973, the country is clearly divided on this issue. While the flotilla was at sea, about 2000 people formed a line the length of Piha beach, one of many events at which people expressed their support for the yachts - whose achievements were limited but nonetheless significant.

They highlighted the fact that drilling for oil in the deep ocean cannot be done without an element of risk, and showed the Government and oil exploration companies that there is no consensus for such operations around New Zealand.

Now, unless Greenpeace succeeds in blocking the drilling through a legal challenge, Anadarko's ship the Noble Bob Douglas will spend 70 days drilling to 4600m. If it has no luck there, it will move to another location along the coast.

Noble Corporation is the Swiss company that owns the ship - which is being used by Texan oil company Anadarko for its explorations. Its visit here is virtually a test run since it was launched just before leaving for New Zealand. The last Noble-owned vessel seen here was the Noble Discoverer, which abruptly ended drilling on the edge of the Taranaki Maui gas field during a storm in April 2011.

The real concerns are wider than threats to our beautiful coastline. Climate change deniers feed on oil exploration.

While our immediate need for oil is indisputable, its contribution to the changes in climate the world is experiencing is also now indisputable.

The search for "dangerous oil", which is difficult and risky to extract, deflects efforts to mitigate our dependence on it and plays into the hands of the deniers whose economic clout - they are among the world's wealthiest companies - undermines the democratic process and stymies political decisiveness.

Climate change is as real as were the effects of nuclear tests in the atmosphere. It is also as durable as radiation and yet our Government, like most others, lacks the courage to take decisions that reach beyond the immediate economic horizon.

But the gap between protesters and Government may be slowly narrowing. This year, the Prime Minister's chief science adviser, Professor Sir Peter Gluckman, issued a report titled "New Zealand's changing climate and oceans: the impact of human activity and implications for the future".

In his summing up, Professor Gluckman wrote: "... the collective wisdom of the scientific community is that action is needed now. It is inherent in the time scale by which emission targeting can affect temperatures that action sooner will have a greater ameliorating effect. This means making decisions in the absence of absolute certainty ... The problem that overlays all of this is one of economics."

This meant, he said: "The conundrum for the politician is real - how to achieve collective action."

New Zealand achieved some form of collective action that helped change the world in 1973. It will take courage to do so again.

• Pat Baskett is an Auckland writer.

Dialogue: Contributions are welcome and should be 600-800 words Send your submission to dialogue@nzherald co nz Text may be edited and used in digital formats as well as on paper