Kelly O'Shanassy has run out of time to be polite over climate policy.
The Australian Conservation Foundation CEO says recent warnings from scientists and two decades of climate inaction mean the gloves are off.
"If we continue to burn coal and gas for decades to come, we will kill the 1.5 degree target, we will not have a habitable planet and hundreds of millions of people will die," she told the National Press Club in Canberra on Tuesday.
"When people are defending burning coal and gas, then that's what they're really talking about - those hundreds of millions of people whose lives will be at risk."
Ms O'Shanassy launched the ACF's campaign to make the forthcoming federal election a battle of climate policy.
"My warning to those in the house up the hill is that if you ignore climate change you do so at your political peril," she said.
"We don't want your thoughts and prayers, we want action."
ACF aim to have one million conversations before the federal election is due in May, specifically targeting voters in three electorates - marginal Liberal seats Chisholm and Bonner, as well as the new Victorian seat of Macnamara.
The organisation has also commissioned climate modelling by the Australian National University to issue during the campaign.
However, Ms O'Shanassy shared modelling predictions for Prime Minister Scott Morrison's southern Sydney electorate of Cook, saying children born today will experience seven and a half months of summer.
Likely independent MP for Wentworth Kerryn Phelps is backing ACF's campaign, saying inaction on climate change will become a health issue.
"I don't believe the Australian population will tolerate a government going forward without a comprehensive policy on climate change," she told ABC radio on Tuesday.
Ms O'Shanassy says the organisation isn't siding with a political party, or telling people how to vote, but will look closely at their climate policies.
Liberal member for Chisholm Julia Banks is weighing up whether to stand as an independent, amid her concerns over bullying and harassment within the party.
Ross Vasta has held the Queensland seat of Bonner for the Liberals since 2010, nabbing 53.4 per cent of the vote at the last election.
