The UN General Assembly adopted the Optional Protocol to the Convention on the Rights of the Child for a Communications Procedure in 2011 and it came into force in 2014.

Sara Austin, founder and CEO of Children First Canada, led the years-long global push for a UN code for children — and their adult representatives — to file complaints if their rights have been violated.

"It really is remarkable to me now to see young people like Greta and 15 of her peers now using this law to file a complaint against five governments and to seek justice for the failure of their government to protect their safe and healthy childhood," Austin, who is based in Calgary, said in an interview.

The complaint this month from the child petitioners — who are between eight and 17-years old and represent 12 countries — is directed at five of the 45 countries that have ratified the protocol: Argentina, France, Germany, Brazil and Turkey. It alleges those countries violate children's rights by failing to address the climate crisis.

"This law is not yet available for kids here in Canada to file a complaint because our government hasn't ratified it, but we hope to see that change," Austin said.

"As a Canadian who was leading these global efforts, I was dismayed and deeply frustrated that my own government was opposed to the law and to this day has not yet ratified it."

Austin said her efforts were motivated by children's rights violations she witnessed through her work in Asia, Africa and Latin America. She recalled spending three years in Thailand, where she encountered kids who were victims of child labour and trafficking. Many were not getting adequate health care for AIDS and other diseases.