Broadly referred to as climate anxiety, research has stacked up to measure its prevalence ahead of UN talks in Glasgow, which begin at the end of the month, to thrash out how to put the 2015 Paris Agreement on curbing climate change into effect.

One of the biggest studies to date, funded by Avaaz, an online campaign network, and led by Britain's University of Bath, surveyed 10,000 young people aged 16-25 in 10 countries. It published its results in September.

The study found around three-quarters of those surveyed considered the future frightening, while a lack of action by governments and industry left 45 per cent experiencing climate anxiety and distress that affected their daily lives.

Elouise Mayall, an ecology student at Britain's University of East Anglia and member of the UK Youth Climate Coalition, told Reuters she had felt guilty and overwhelmed.

"What I'd be left with is maybe the sense of shame, like 'how dare you still want lovely things when the world is ending and you don't even know if you're going to have a safe world to grow old in'.

"You might have sadness, there might be fear, there might be a kind of overwhelm."

Caroline Hickman, a psychotherapist and lecturer at the University of Bath and one of the co-authors of the research, is working to help young people manage climate-related emotions

"They're growing up with the grief and the fear and the anxiety about the future," she said.

London-based psychiatrist Alastair Santhouse sees climate change, as well as COVID-19, as potentially adding to the burden, especially for those pre-disposed to anxiety.

"Some anxiety about climate change is motivating. It's just a question of how much anxiety is motivating and how much is unacceptable," said Santhouse.

"The worry is that as climate change sets in, there will be a more clear cut mental health impact."

Among some of the world's communities that are already the most vulnerable, extreme weather events can also cause problems such as post-traumatic stress disorder.

Leading climate campaigner Greta Thunberg, 18, has experienced severe climate anxiety.

"It's a quite natural response, because, as you see, as the world is today, that no one seems to care about what's happening, it's only human to feel that way," she said.

For now, however, she is hopeful because she is doing everything she possibly can.

"When you take action, you also get a sense of meaning that something is happening. If you want to get rid of that anxiety, you can take action against it," Thunberg said.

Australian Associated Press