In a demands letter, the activists demanded from the gvernment to "tell the truth by declaring a climate and ecological emergency, working with other institutions to communicate the urgency for change."

The also demanded the government act to halt biodiversity loss and reduce greenhouse gas emissions to net zero by 2025.

Exctinction Rebellion member Fraser Maywood said he had never thought much about climate change during his 35-year career in the international oil and gas industry.

But over the years, he noticed people had left his industry and some began to work in fields that looked at the impact of climate change on areas such as agriculture, insurance, property and food security.

Now 60 and semi-retired, Mr Maywood more recently became aware of the school strikes, the work of Greta Thunberg and the sheer diversity of the people getting involved in climate debate, including his teenage daughter.

“This was not about an ideology, there are a lot of scientists but also other professions,” he said.

“We are benefiting from a fossil fuel industry ... we are all in some way complicit.

“Our children, what kind of world are they going to inherit from us?”

He and his wife had heard about Extinction Rebellion through its UK activity, and went to a talk at a Perth community hall.

“Yes, the young and radical, but also people like me – who care about the forests but probably wouldn’t march on Parliament for them.”

He said the organisation was non-hierarchical and “cellular” in that there was no central leadership.

He said he was a law-abiding citizen and the thought of protesting was “a bit frightening”, but his decision was spurred by his thoughts about the unwritten but understood “social contract”.

“You work, you pay taxes and obey the law and in return the government uses that money for your best interests and protection against whatever is the threat facing the nation,” he said.

“Understanding that social contract was broken gave me an ethical basis for civil disobedience ... there is a requirement that we act in the best interests of humanity.

“People ask about our solutions. I don’t have a solution. But we want to alert the public to this real climate emergency,” he said.

“Species are dying out and it’s not yellow-bellied parrots we are talking about, it’s losing a huge percentage of our flying insects, for example – the insects we need to pollinate food. It’s about our ability to feed our children, and for them to feed theirs.”