Young activists have vowed to keep protesting in Edinburgh despite the city council saying it will only authorise pupils to miss school once a year to attend climate strikes.

Pupils have been attending protests on Fridays outside the Scottish parliament on an ad hoc basis after the council granted permission in March.

On Friday, however, the council’s education, children and families committee approved a motion by the Scottish National party-Labour coalition to limit authorised absences to one day. Activists had asked the council to support pupil participation in the continuing global movement started by 16-year-old Greta Thunberg.

The council insisted it would not punish children for taking part in subsequent strikes but it said parental consent would be required.

Edinburgh’s education convener, Ian Perry, said: “We support the young people making their voices heard regarding climate change as it is one of the most important issues that’s facing the world. However, there needs to be a balance struck and if we allow pupils more than one absence the issue is that they could be regularly missing school which affects their education.”

Sandy Boyd, a member of Scottish Youth Climate Strike, said the decision was disappointing but added: “I’m still confident that our movement won’t be deterred by it. The council is short-sighted if it thinks one strike a year is enough to make this change. This movement will not stop and we’ll keep striking no matter what.”

Q&A Why is the Guardian changing the language it uses about the environment? Show The Guardian has updated its style guide to introduce terms that more accurately describe the environmental crises facing the world. Instead of “climate change”, the preferred terms are “climate emergency, crisis or breakdown” and “global heating” is favoured over “global warming”. The scale of the climate and wildlife crises has been laid bare by two landmark reports from the world’s scientists. In October 2018, they said carbon emissions must halve by 2030 to avoid even greater risks of drought, floods, extreme heat and poverty for hundreds of millions of people. In May 2019, global scientists said human society was in jeopardy from the accelerating annihilation of wildlife and destruction of the ecosystems that support all life on Earth. The editor-in-chief, Katharine Viner, says: “We want to ensure that we are being scientifically precise, while also communicating clearly with readers on this very important issue. The phrase ‘climate change’, for example, sounds rather passive and gentle when what scientists are talking about is a catastrophe for humanity.” Other terms that have been updated include the use of “wildlife” rather than “biodiversity”, “fish populations” instead of “fish stocks” and “climate science denier” rather than “climate sceptic”. Damian Carrington Environment editor

With Scottish secondary school pupils returning from the summer holidays this week, strikers moved their regular Friday action from Holyrood to the council’s offices at lunchtime, with about 30 young people congregating.

Boyd said: “These actions are happening on a weekly basis, but authorisation is good on big dates like September 20 and 27 because lots of people want to come out [for the global climate strikes] and it allows them to come out feeling safe, and that they won’t be reprimanded.”