As the search for a British man missing on Everest continues, one Irish adventurer says climate change has left the mountain less stable. 

Dan Paterson (40) and his Nepalese guide Pastenji Sherpa (23) haven't been heard from since Tuesday when part of a ridge collapsed on the world's highest mountain. 

Footage online showed an overcrowded summit with hundreds of people queuing to get to the top. 

Pat Falvey, the first man to climb the seven summits twice, said mountains around the world have become more dangerous due to climate change. 

“Due to global warming and climate change now, most of Mount Everest and all the high mountains around the world are becoming more dangerous,” he told Newstalk. 

“Mainly due to avalanche rock falls, which is what happened on Mount Everest this week.” 

Mount Everest and surrounding peaks viewed from Gokyo Ri

He agreed the increased number of climbers may also increase the chance of people going missing. 

“The amount of people now that are travelling on Everest is a hell of a lot more than what it was, and it can affect the stability of the snow and the ice. 

“I think over 450 people were signed up this year - and of course when you're on a narrow ridge where people have to pass each other is increasing the dangers if anything happens.” 

Mr Falvey said people will “of course” continue to climb the summit for as long as it’s available to them. 

“Unless the government put restrictions on the numbers that can go in any given day, it does increase the dangers of the top of Mount Everest,” he said. 

The family of Mr Paterson has launched an "urgent" crowdfunding page to locate him. 

They are raising £150,000 to cover expenses such as helicopter flights and aerial searches, specialised search teams and equipment, and communication and coordination efforts. 

So far, the GoFundMe has raised £125,000.