"Now, it's yesterday, last week, this month," Mr Gore said at the Investor Group on Climate Change Summit in Sydney.
Climate change was happening now, not the future, bringing with it back-to-back floods and wildfires in Australia and around the world, he told the sustainable investment conference on Friday.
Australia has been struck by floods, storms and a devastating algal bloom in the past year, events turbocharged by record-high ocean temperatures.
"It's important for all of us not to normalise what's going on now and make it the new normal," he said.
"We're wired to do that."
"But we have to recognise that in our lifetimes, there are things happening that are consequential for all generations to come, unless we can act."
The forerunner of the modern climate movement was critical of his own country's decision to leave global climate pact the Paris Agreement, but he said international commitment was still strong.
"One hundred and ninety-five minus one does not equal zero," he said.
"Countries other than the United States are still moving forward, some of them more slowly."
Despite the pushback on climate action from the Trump administration, progress was being made in the US, including a "huge surge" in renewables, particularly solar and batteries. Â
"I'll remind you that the previous four-year term of Donald Trump, solar doubled in the US," Mr Gore said.
The climate advocate complimented Australia's record on renewables, highlighting the sun-baked country's leadership in rooftop solar.
NSW Climate Change Minister Penny Sharpe, told the same conference her state had committed to mandatory climate disclosures for government agencies.
"This is about transparency, it's about making sure that government leads by example," she said.
Australia has been phasing in compulsory climate risk reporting, starting with big companies and financial institutions.
The move elevates climate reporting to the same level as traditional financial disclosures.
