Mr Turnbull drew some sensible conclusions about what Australia must do about climate change, but what he did not say is of more import.

In an essay commissioned by The Guardian Australia for its 2020 Vision series, Turnbull wrote, quite reasonably: "The lies of the deniers have to be rejected ... Climate change is real ... Our response must be real too - a resilient, competitive, net zero-emission economy - as we work to make our nation, and our planet, safe for our children and grandchildren."

This is the view of the man who was prime minister for three years and in cabinet for five years, including a stint as Environment Minister. So the big question is: why didn't his view become Australian law and policy?

More broadly, the Australian people are entitled to an answer to the critical question: how did the three major political parties so comprehensively fail to deliver the climate policy the nation has needed for more than a decade?

A big part of the answer to that question must be within the power and knowledge of Turnbull to answer. He was at the helm when it should have happened. He was at the helm when he wanted it to happen, and he was at the helm when it didn't happen. Why was that? How did that happen?

Why weren't the lies of the deniers rejected?

We know that Australian policy alone would not have affected the fires, but effective Australian policy would have given us the moral high ground to urge other nations to do a lot more so future effects would be lessened. This is important, because Australia is among the countries likely to be most affected by climate change, as we have seen this summer.

Let's go back to the beginning with this royal commission (and by the way, why can't we give these inquiries a different name - an Australian Commission of Inquiry, for example?).

The starting point is December 2, 2009. A day after Tony Abbott replaced Turnbull as Liberal leader, the Greens voted with the Liberal and National Parties in the Senate to reject Labor's carbon-pricing scheme.

Those Green senators, especially then-leader Bob Brown, should be put in the box at the inquiry and asked what possessed them to side with conservatives to defeat a pretty good start to addressing, in the words of then-prime minister Kevin Rudd, "the great moral challenge of our generation".

Then when the bill got knocked back in the Senate, Labor did nothing. Rudd and the senior Labor leaders in 2009 should be asked why they allowed short-term political considerations to take priority, and why they did not then and there put the bill up a second time and go to a double dissolution to address this "great moral challenge".

Why didn't Rudd stare down the Greens and give them a last chance to support his carbon-pricing scheme or face a double dissolution with Labor putting the Greens last on their how-to-vote-cards?

Rudd should then be asked why, in April, 2010, he chose to defer further action on the "moral challenge" to 2013.

The Australian people are also entitled to answers when it comes to what happened to the Liberal Party when Abbott took the helm.

How is it that a Rhodes Scholar like Tony Abbott can pretend not to understand basic climate science and say it is "crap" and order his party to reverse Turnbull's support for carbon pricing? Why did the leader of a so-called free-enterprise party reject the market approach?

He should be asked whether the financial support of the fossil industry affected that decision. Or whether it was just political expediency to run an anti-carbon-tax scare campaign.

The inquiry should dig deep and hard into the finances of the Liberal and National parties to find out the level of donations and ask the donors in the witness box why they gave the money and what policy positions they expected in return.

Abbott should be grilled about his habit of announcing emissions targets but doing little or nothing to achieve them.

Julia Gillard should be questioned, too, about walking away from carbon pricing after her factional supporter Bill Shorten specifically cited Rudd's walking away from that very carbon pricing as a reason for her challenging his leadership.

To her credit, though, she returned to it - because it was good policy. Tragically for her, the way she took the prime ministership tainted what she did as prime minister. Like Malcolm Fraser, she should have waited for it to fall into her lap, but didn't.

Abbott should be grilled about why he repealed the Gillard carbon price when it was working so well to reduce emissions.

The Australian people are entitled to know what promises Turnbull made as a condition of getting the prime ministership - promises that hamstrung him into weak policies that favoured fossil-fuel industries.

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How could he sweep away the knights and dames with such ease, but not redo climate policy? Why did he get done over at every turn like no other prime minister? How and why were all his climate policies stymied? Why did he do nothing about it?

Why didn't he come out early on when he was popular, reveal to the Australian people what the troglodytes were doing, and reverse it?

Prime Minister Scott Morrison should be questioned about why he gave coal such symbolic power, and continues to give it such actual power in Australia's parliament.

Every Coalition MP since 2009 should be grilled about how and why they voted for pro-fossil-fuel policies, their diaries examined for meetings and their accounts audited for fossil-fuel donations. Because even after these fires, they are still at it.

As to the fires themselves, the Victorian royal commission into the 2009 Black Saturday fires did the hard work on the technicalities of fighting fire and reducing the risk to lives and property. And it was very successful. In those fires, 179 people died. This time, with a greater area burned, 27 people have died. Lessons have obviously been learned.

And the greater lesson is that hard policy and technical work in all fields of endeavour does more than any glib slogan.

The commission should also put the lie to the greenies preventing hazard-reduction burning, because it was the heating climate that reduced the window for safe burning. It should reveal all the public service advice about not only combatting the foreseen huge fire risk, but also combatting the global heating that causes it. And it should ask the politicians why they rejected so much of it.