I write this piece reluctantly, because there are still possible fire victims unaccounted for; people have lost loved ones; and hundreds of families have lost their homes. My heart goes out to them. I don’t want to detract in any way from the vital safety messages that our fire commissioners and Premier will be making about Tuesday’s fire potential.

Gladys Berejiklian speaks on the alarming nature of the NSW bushfire crisis.

Everyone needs to heed the fire service warnings to prepare, to have a plan, and to leave early if you’re not properly prepared. Know that the best firefighters in the world – volunteer and paid – will be out in force from NSW agencies and interstate to do battle with the worst that an angry Mother Nature can throw at us. But as we saw on Friday, the sheer scale and ferocity of mega fires can defy even the best efforts.

In the past I have heard some federal politicians dodge the question of the influence of climate change on extreme weather and fires by saying, "It's terrible that this matter is being raised while the fires are still burning." But if not now, then when?

"Unprecedented" is a word that we are hearing a lot: from fire chiefs, politicians, and the weather bureau. I have just returned from California where I spoke to fire chiefs still battling unseasonal fires. The same word, "unprecedented", came up.

Unprecedented dryness; reductions in long-term rainfall; low humidity; high temperatures; wind velocities; fire danger indices; fire spread and ferocity; instances of pyro-convective fires (fire storms – making their own weather); early starts and late finishes to bushfire seasons. An established long-term trend driven by a warming, drying climate. The numbers don’t lie, and the science is clear.

If anyone tells you, "This is part of a normal cycle" or "We’ve had fires like this before", smile politely and walk away, because they don’t know what they’re talking about.

In NSW, our worst fire years were almost always during an El Nino event, and major property losses generally occurred from late November to February. Based on more than a century of weather observations our official fire danger season is legislated from October 1 to March 31. During the 2000s though, major fires have regularly started in August and September, and sometimes go through to April.

The October 2013 fires that destroyed more than 200 homes were the earliest large-loss fires in NSW history – again, not during an El Nino.

This year, by the beginning of November, we had already lost about as many homes as during the disastrous 2001-2002 bushfire season. We’ve now eclipsed 1994 fire losses.

Fires are burning in places and at intensities never before experienced – rainforests in northern NSW, tropical Queensland, and the formerly wet old-growth forests in Tasmania.

Burning properties in Rainbow Flat after fire from the Hillville Fire broke containment lines and crossed the Pacific Highway. Dean Sewell

On Friday, the NSW Rural Fire Service sent out an alert that fires were creating thunderstorms – pyro-convective events. In my 47 years of fighting fires I don’t remember this happening much. Now it happens quite regularly. On Friday, the atmosphere was relatively stable and therefore shouldn’t have been conducive to these wildly unpredictable and dangerous events. Yet it happened. Unprecedented.

The drought we are facing is more intense than the Millennium Drought, with higher levels of evaporation due to higher temperatures. This has dried out the bush and made it easier for fires to start, easier for them to spread quickly, and as we saw on Friday, enabling spot fires to start twice as far ahead of the main fires as we would normally expect.

Warmer, drier conditions with higher fire danger are preventing agencies from conducting as much hazard reduction burning – it is often either too wet, or too dry and windy to burn safely. Blaming "greenies" for stopping these important measures is a familiar, populist, but basically untrue claim.

Together with 22 other retired fire and emergency service chiefs, I spoke out earlier this year. We felt we had a duty to tell people how climate change is super-charging our natural disaster risks. I wish we were wrong, but we’re not.

I’m confident that our national government, when the smoke and dust settles, will finally see the obvious and understand the word "unprecedented". I’m sure it will then start to take decisive action to tackle the base cause – greenhouse emissions - then use the high moral ground to lean on other countries to also do the right thing.

In the meantime, please, please play it safe, and act on the vital fire service warnings.

Greg Mullins is a former Fire and Rescue NSW commissioner and a councillor on the Climate Council.