The impact of climate change has forced the organisers of the World Athletics Championship to alter its schedule as host city Budapest suffers from excessive heat.

As the temperatures soared the organisers moved yesterday’s heats for the women’s’ 5000 meters from late morning to late afternoon amid fears for the safety of the athletes. It is expected that the temperature in the Hungarian capital will hit 35C in the coming days and while the two marathon events will start early morning this weekend runners will still be competing in temperatures of 27C.

The country’s chief medical officer this week declared a second-degree heat alert for the country between 2pm on Monday until Thursday midnight. People are being advised to stay in cool places and avoid physical exertion between 11am and 5pm on those days.

The news came as team management from some of the world’s most climate exposed nations which are participating in the event warned that their very existence is threatened by the extreme weather events and the impact of global warming.

“Land is gradually fading away due to coastal flooding”, according to Tuvalu Athletics’ general secretary, Niuone Eliuta. “It is scary to live on an island at the frontline of climate change. If things carry on the way they are going, in 50 to 100 years we may not even exist.”

Bob Ramsak, head of sustainability at World Athletics, said: “These countries really are on the front line of the global environmental crisis,” he said. “They’re facing literal, physical extinction if something doesn’t change.

“And it’s not their fault. They’re doing what they can, as countries and in athletics. But it needs the rest of us, including international bodies like World Athletics to do more.

“A World Athletics survey showed that 77% of athletes are very or extremely concerned about climate change. It’s a live issue for them so we must use their voices to get the message across.

“And we have to figure out a way to use our influence to de-carbonise our events.”

Before the event began World Athletics president Seb Coe had warned that climate change, had the potential to impact not only this week’s event but the ability for cities to host future championships, adding that it may also necessitate the timing of the championships to be changed to take into account the temperatures and to protect the athletes.

“It’s something that I have felt very strongly about for a long time,” he said. “Constituent groups like sport are going to have to figure this out for themselves, because I don’t think we can rely on governments to remotely get to grips with what is going to be a massive shift in reality in the next few years.

“There are countries in our federation that will probably not be in existence in the next 20 years. I think we are going to have to spend a great deal of time thinking about what the calendar looks like and maybe . . .  uncoupling some of the tougher endurance events from our world championships in the summer months.”