Siobhan Sutton is an academically talented high school student, but is proudly choosing to fail a maths test today.

Key points: The School Strike for Climate is a global movement inspired by Greta Thunberg

The School Strike for Climate is a global movement inspired by Greta Thunberg Strikes have been arranged across the country at every major city

Strikes have been arranged across the country at every major city Many students risk failing tests and their absence will be officially "unauthorised"

She will get 0 per cent for the test because she will not be at school to sit it, instead joining thousands of students across Australia to take part in the global School Strike for Climate.

Inspired by Swedish teenager Greta Thunberg, the movement spread to Australia last October and tens of thousands of students nationally have taken part in rallies since then.

Australian school protesters want the Federal Government to commit to:

No new coal, oil or gas projects

No new coal, oil or gas projects 100 per cent renewable energy generation and exports by 2030

100 per cent renewable energy generation and exports by 2030 Funding for "a just transition and job creation for all fossil-fuel industry workers and communities"

Sorry, this video has expired Students walk out of school to rally for action on climate change

Siobhan, 15, attends the academically selective Perth Modern School and today's maths test is worth 25 per cent of her overall grade.

Despite having the support of her mother, her absence today will be recorded as "unauthorised", meaning she will get an automatic fail.

But Siobhan said she did not care.

"I have basically been told that because it is not a valid reason to be missing school, it is not a medical reason or anything, I am going to get a zero on the test if I don't actually sit it," she said.

"Even though we ourselves aren't sick, the planet which we live on is, and we are protesting and fighting for it.

"We are in the midst of a climate crisis, and Australia is in the thick of it."

For parents, it's a question of priorities

Siobhan said her maths teacher had given her the option to sit the test before school on Friday, but she was unable to do so because of her commitments as one of the organisers of the climate strike.

She would also rather fail the test in order to take a clear stance on the issue.

Her mother Antje said she was very proud of her daughter.

Siobhan Sutton's mother Antje supports her daughter's decision to skip school for the climate strike. ( ABC News: Rhiannon Shine )

"Grades and education matter very much and Siobhan would agree with that," she said.

"But they only matter if you have a bright future to look forward to. If that future is in danger, we should do everything to prevent that danger from taking effect.

"You have to get your priorities right. It is regrettable that she is going to get a zero [on her test], but it is more important to be involved in the action that could make a difference to her future."

Punishment for missing school today to attend the strike is decided on a state-by-state basis.

In WA, Education Department policy dictated that if a student chose to miss school and was not there to sit a test, the teacher could not record a mark for them.

"As Friday is simply another school day, I expect public schools won't change the way they run and mark scheduled tests on that day," deputy director general Stephen Baxter said.

"An 'authorised absence' is one where the student's parent has provided the principal with a valid and reasonable explanation for the absence — for example, the student is sick or has a medical appointment."

Hundreds of students protested at South Australia's Parliament House late last year. ( ABC Radio Adelaide: Malcolm Sutton )

An 'unauthorised absence' meant no explanation was given, or the reason provided by the student's parent was not acceptable.

'Consequences for choices'

Armando Giglia, president of the WA Secondary School Executives Association (WASSEA) which represents principals and deputies at the state's 166 public high schools, said students would not be penalised simply for missing school to protest, provided they had parental support.

But he said test and assessment dates were set early in the school year and students had a choice to make.

"There are consequences for choices," he said.

"If a student is making a choice to go to the rally that is terrific, and they have a right to do that, but they are making a choice.

Armando Giglia says it is important for students to understand the consequences of their actions. ( ABC News: Rhiannon Shine )

"If later in life you were working and you were going on strike, there is a consequence — it would cost you a day's pay to make your point.

"In this case, if it costs you an assessment, that is their choice."

Mr Giglia said he believed if the movement continued to grow in the future, and schools had plenty of notice, they might start to schedule assessments around the protest.

"There are a lot of good teaching points in all of this and we want kids to have a voice on this," he said.

Student wins test reprieve

Aranmore Catholic College Year 11 student Brando Arimborgo was faced with a similarly difficult decision.

He wanted to take part in today's climate strike, but risked missing a scheduled physics test.

After discussing the situation with his school, teachers agreed to make an exception and allow him to sit the test on Monday instead of today.

"It would be really good if [schools] could change the rules so that people could still attend the strike and also do their test maybe the next day or before," he said.

Brando Arimborgo hopes to attend the climate strike, if he can reschedule a physics exam. ( ABC News: Rhiannon Shine )

The union representing school teachers has thrown support behind the school climate strike.

"Teachers understand the democratic right that students have to take part," State School Teachers Union WA acting vice president Natalie Blewitt said.

"I think they are doing the best they can to support the students however they can.

"We would be asking for teachers and school leaders to be flexible so that students who are exercising their democratic right to attend the climate action, that they would be able to have assignments or tests actually postponed."

Natalie Blewitt believes most teachers are doing what they can to support students. ( ABC News: Rhiannon Shine )

Education in and out of the classroom

WA Education Minister Sue Ellery said she understood why students were taking part, but her role required her to ensure young people attended school.

"I can understand young people being concerned about climate change and I can understand them frankly being disappointed in my generation for not acting sooner," she said.

"I encourage them to be involved in public policy and if their parents are happy with them attending any events then that is fine.

"My job is to implement and adhere the school's legislation and that requires that students attend school. But I also appreciate that this is an important policy issue for all of us and young people are really concerned about it."

Catholic Education Western Australia (CEWA) executive director Debra Sayce said while young people were concerned about the environment and climate change, they were expected to attend school.

"Catholic school students are better placed to engage in learning and conversation about important social and political issues at school than at non-educational events," she said.

The climate strike movement started spreading across Australia last year. ( ABC News: Rhiannon Shine )

Antje Sutton said her daughter had gained more life experience as an organiser of the climate strike than she could learn in a classroom.

"She has been liaising with the [City of Perth], the police, with unions. Many adults wouldn't have the courage or the ability to do that," she said.

A new report by the International Federation of Red Cross titled The Cost of Doing Nothing estimated that by 2050, 200 million people every year may need international humanitarian aid as a result of climate–related disasters and the socioeconomic impact of climate change.

"With determined and ambitious action, the number of people in need of international humanitarian assistance as a result of climate-related disasters annually could also be as low as 68 million by 2030, and even drop to 10 million by 2050 — a decrease of 90 per cent compared to today," the report stated.