Seven children are to sue European governments in a landmark lawsuit over the impact that climate change is having on their lives.

The Portuguese youngsters, some from the Leiria region which has been devastated by wildfires twice this year, are seeking a ruling to force 47 countries to dramatically cut greenhouse gas emissions.

And they want the European Court of Human Rights in Strasbourg to order nations to keep remaining fossil fuel reserves in the ground.

One of the children spearheading the unprecedented case is 18-year-old Claudia from the Leiria district, who said older generations have a responsibility to stop releasing dangerous pollution.

"What worries me the most about climate change is the rise in temperatures, which has contributed to the number of fires taking place in our country," she said.

Claudia said she is taking the case "for the children and for the future generations who are not responsible for the current state of the environment".

Three days of national mourning are being held in Portugal after scores of people died as deadly forest fires twice hit the country this year.

Outbreaks in June claimed 64 lives and another 41 are believed to have been killed in the last week after winds associated with Storm Ophelia fanned flames sparked in drought-like conditions.

A state of emergency was declared in areas north of the river Tagus - almost half of Portugal - and prime minister Antonio Costa acknowledged that climate change was a factor in the recent outbreaks.

The seven youngsters have the backing of the non-profit Global Legal Action Network (Glan) and a team of barristers from London's Garden Court Chambers.

While £20,000 has been raised on the platform to launch the case, lawyers said the full names of the children are being withheld to protect them.

The other youngsters include a 14-year-old called Martim, Mariana, aged five, Leonor aged eight, Andre aged nine, Simao aged 11 and Sofia aged 12.

In video messages, made to coincide with the lawsuit, Simao said: "I am worried about climate change because it entails global warming, sea level rise and fires.

"Older generations should reduce the consumption of natural resources, reuse materials and recycle them.

"I want to have a future."

The lawyers backing the case claim that the 47 nations which are party to the European Convention on Human Rights are collectively responsible for about 15% of global emissions.

Dr Gearoid O Cuinn, Glan director, said: "This is not about seeking damages. This is about the future of children.

"The governments know the science. They know the risk. The governments are just slow to act. It's like it was with big tobacco."

The case seeks a ruling on behalf of the youngsters that a failure to slash emissions and switch from fossil fuels poses a significant threat to their human rights, primarily the right to life.

They claimed that the children's case could have significantly more influence on climate policy that the Paris Agreement.

Gerry Liston, Glan legal officer, said the European Court of Human Rights is being asked to determine emissions based on current climate science.

"Glan will work with civil society organisations throughout Europe to use our case to highlight the fact that unless governments urgently take much stronger action to prevent the release of greenhouse gas emissions, it is only a matter of decades before we'll be witnessing the catastrophic consequences of insufficient action," he said.