A headline trumpeting the possibility of $32 billion in royalties makes the news of a larger than projected Barque oil and natural gas field off the North Otago coast sound appealing.

And that is the point. New Zealand Oil and Gas (NZOG), the operator of the Clipper joint venture where the Barque prospect is situated, is trying to build support for possible underwater exploratory drilling, which it needs to decide on by April next year or surrender its permit.

But dig a little deeper and the numbers are not quite as rosy. Projected royalties are $16.7b and taxes another $15.4b, and that is over a projected 46-year economic life of the field. NZOG says annual royalties would be $330 million annually, and that is only if the natural gas is piped to shore in Timaru (the field itself is located about 60km east of Oamaru, 2.5 to 3 kilometres below sea level, under 800 metres of water).

As NZOG has said, estimating royalties is a tricky business. They said there was a 20 per cent chance of finding the estimated reserves, up from an estimate of 10-20 per cent in 2015, which would make any prudent investor discount that headline number significantly.

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John Kidd, director of sector and equity research at Woodward Partners said: "There's a four out of five chance of zero result. That's the game. Oil and gas is a business of risk. The risk piece of this is well understood internationally."

Financial risk for NZOG is the least of the issues. Undersea drilling at a depth of almost a kilometre and building a pipe to shore are both risky activities and if the potential rewards for the company are high, so are the potential risks of environmental catastrophe.

But the biggest risks of all are the climate change effects that are accelerated by releasing fossil fuels from their undersea lockers. At the same time as NZOG was releasing its economic impact report on the Barque prospect, the World Meteorological Organisation released its annual report on carbon dioxide levels, showing that CO2 levels in the atmosphere increased at a faster rate in 2016 than anytime in at least the previous 30 years.

CO2 levels are now higher than anytime in the past 800,000 years – longer than our species has existed. Scientists warned that the last time CO2 levels were this high for an extended period the temperature was 2-3C warmer and sea levels were 10-20m higher due to the melting of ice caps.

Set against those kinds of scenarios, high-risk efforts to unearth more fossil fuels should not be seen as New Zealand's path to economic success. Our high-tech future will be powered by electricity from renewable sources and larger economies like Germany, China and California have pinned their economic growth strategies on investments in renewable energy.

Canterbury's new ministers, Energy and Resources Minister Megan Woods and Minister of Conservation Eugenie Sage, will have significant oversight over applications for more fossil fuel exploration. They should not encourage the 20th century mentality of doubling down on drilling.

It is past time for New Zealand to live up to its valuable clean, green image and make a sincere effort to cut its CO2 emissions.