Oil companies and the Government need to be more open about the potential effects of an oil spill, writes Greenpeace's Simon Boxer.

There is no substitute for facts and figures," thundered the Dominion Post leader on deep-sea drilling (Riches, or ruin? Reassurance is vital, Oct 25).

I could not agree more. But unfortunately, the debate about deep-sea oil drilling in our waters has been far, far too absent of facts and figures.

The reason? The oil industry and the Government have been keeping information hidden. They have compiled information about the potential impact an oil spill may have.

They will have modelled spills, and projected how long it would take to stop such a disaster happening.

This is all hugely important. And, if we are to have a frank and open discussion, it's vital for the public to see this information.

But we haven't been able to have a frank and open discussion because this information is being kept hidden from the public.

These facts and figures, on which a vital decision about the future of our country is being made, have not been released in full by either the Government or the oil industry.

That's why we released information about the potential impacts of an oil spill, because the oil industry and the Government were not. The computer model used 10 years of climate and weather data to model hundreds of spill trajectories and predict the possible outcome of an oil spill.

The model showed what could potentially happen if there were a blowout at two planned locations off the west coast of the North Island and the east coast of the South Island.

In the immediate hours after we released this information, Anadarko, the Texan oil company due to start drilling at those very locations, admitted that its own worst case scenario showed oil from a spill hitting our shore.

But apart from this rare, albeit welcome, moment of openness, oil industry lobbyists, rather than releasing the information they hold on oil spills, started making things up.

First, for the model, we assumed the oil was a medium crude. We assumed this because its weathering properties are similar to oil types known in New Zealand. We did not model heavy black oil, as some critics tried to say we did.

That's because it would not be accurate. And, as annoying as the oil industry may find it, we do base our campaigns on evidence, and openness and transparency.

We took account of the differences between New Zealand and the Gulf of Mexico. Our maps online and in the media didn't even depict a Gulf of Mexico-type scenario and were instead based on a spill one-sixth the volume of the Gulf of Mexico spill.

This main scenario in our modelling was a spill of 10,000 barrels of oil a day for 76 days.

This now looks conservative, as even Shell has just shown that its modelling shows the same spill rate, but for 30 days longer for shallow-water drilling.

I wonder why the oil lobbyists aren't queuing up to label this as "scare- mongering", when it's eye-wateringly obvious that report is based on industry standard parameters.

This is a very important debate. And it is not a proper debate unless we bring in economics. But if you want prosperity, jobs and an economic boost provided by the energy sector, the oil industry simply is not the place to go.

Almost 30,000 jobs could be created in areas such as the geothermal and bioenergy industries right here in our country.

The geothermal industry alone could have export opportunities worth more than NZ$4 billion to the economy every year. And an effective transport policy package could see New Zealand becoming increasingly less reliant on foreign oil imports, saving the country more than $7b each year by 2035.

We're not saying "let's stop using oil tomorrow". We're pragmatic, and we're realists. We use oil in our cars, and in our boats.

We need to shift away from polluting fuels, but that transition isn't going to happen overnight. We're absolutely aware of that.

But we are saying, let's stop deep-sea oil drilling. It's a lot more risky, it's a step too far.

Let's have this debate. We realise that there's going to be people in favour of deep-sea oil drilling. But there's no way we can have a sensible discussion while the Government and the oil industry continue to hide their findings from the country, and spread misinformation.

Simon Boxer is the head of Greenpeace's energy campaign.

This blogpost originally appeared as an opinion piece in The Dominion Post, available here: