The very first night at Budapest's National Athletics Centre last Saturday (August 19) set the tone for the following eight days. The fare on offer had already been entertaining enough with a Championships record from the United States' Ryan Crouser had followed closely-fought heats in which some of the sport's top names were pushed hard in the men's 1500 metres and 100m.

What followed was a women's 10,000m final with a thrilling finish as Olympic champion Sifan Hassan of The Netherlands appearing to have timed her run to the finish line to perfection, only to stumble in a head-to-head with Gudaf Tsegay to give the Ethiopian a clear path for the remaining metres to the world title.

Remarkably, the Dutch faced the same fate in the mixed 4x400m relay, in which Femke Bol had been on the brink of carrying her team to gold before a fall metres from the end enabled the US to triumph in Championships record time. Tonight, Bol came full circle with perhaps the performance of Budapest anchoring her team to women's 4x400m relay gold from way back.

Unexpected. Gripping. World-class. Brutal.

A small selection of the words that could be used and it is difficult to think of a day at the Championships that has not lived up to that billing,

Another theme of the Championships has been the temperatures. After the furious thunderstorm on day one - from which it took this reporter the entire morning to dry off having been caught in it for no more than two minutes - it has been hot. At least as hot as the television pictures have suggested.

It has peaked at around 36 degrees Celsius and in the direct sunlight has not dropped below 33, and a lack of wind has provided sticky temperatures throughout.

Heat concerns have led to some scheduling changes, with the women's 5,000m heats on Wednesday (August 23) shifted from the morning to the evening session and the men's and women's 200m brought forward to account for it.

For today's mass participation race - a commendable initiative that has been a welcome addition to the World Championships and will be at the Olympic Games in Paris next year - organisers felt compelled to reduce the distance from 10 kilometres to 6km and advise "only those whose bodies are used to running in warm weather".

At the National Athletics Centre, evasive action has been taken to help spectators avoid the worst of the heat, whether by allowing them to move from allocated seats in the sunlight into shaded areas or stocking up on water.

Weather conditions have long been a factor in sport. In the last decade in particular, governing bodies have introduced some small changes to account for it - I recall the bemusement of seeing a cooling break at a men's FIFA World Cup for the first time in Brazil in 2014.

As a Briton brought up where the standard summer features a couple of weeks of warmth as a break from cloud and rain, heat is a novelty I relish.

Yet at the risk of being branded a "doom-monger", after Budapest I believe the rapidly worsening impacts of climate provide a genuine threat to the sporting calendar as we know it. In that I include the World Athletics Championships, FIFA World Cups. And yes, the Olympic and Paralympic Games.

It is an indictment on global leaders that the planet has sleep-walked its way into a position where wildfires are longer, more frequent and more difficult to put out, fossil fuels continue to burn despite the availability of greener alternatives, and single-use plastic continues to pollute oceans.

It is an indictment that on Monday (August 21) at the World Championships, athletics leaders from the Cook Islands, Kiribati, Samoa, Tuvalu and Vanuatu had to sit at a table in front of members of the world's media and plead for immediate action. The threat faced by several of those countries and territories is existential given rising sea levels.

The comments of Vanuatu Association of Sports and National Olympic Committee President Antoine Boudier regarding sport's role in tackling the crisis were particularly impressive, cautioning of the need for a reality check in terms of its on-the-field ambitions,

"Today when we are talking about a way forward with sports and athletics in general, we've got a climate footprint on one hand, and we're saying we want to save the planet but we want better shoes, better equipment, better running track and fields," he said.

"It doesn’t match. "We are actually talking two different languages going opposite to each other.

"How can we find the middle ground? I'm pretty sure by finding that middle ground will make a big change to the planet.

"Over the years, people have been expecting to be better, more beautiful, to be the best so people can remember those Games forever, but at a price.

"I think we need to reverse that cycle today."

World Athletics President Sebastian Coe is far from alone in fearing Governments will fail to meet pledges on climate change, whether limiting global warming to 1.5 degrees Celsus or achieving net-zero emissions by 2050.

He recognised the threat posed to the schedule by high temperatures prior to the World Championships.

"We are going to have to think about this, and maybe some of our endurance events, particularly the road, need to be staged at times of year where you are not putting the athletes at risk," Coe admitted.

"There are branding issues, but maybe we are going to have to include some of those events inside the big city marathons.

"It's not beyond the wisdom of all of us to figure this out, but this is a challenge that isn't going to go away."

Coe said the issue had been discussed during the visit of International Olympic Committee President Thomas Bach to Budapest over the weekend.

Bach himself has previously acknowledged the impact climate change could have on the timing of sports events.

"He and I both agreed that it will need addressing, because that situation is not going to change any time soon, and it is really irrelevant now where we stage our Championships. Thirty or 40 years ago you were pretty sure some were going to be more challenging than others, but you didn’t have that extraordinary range of challenge," Coe said.

"I was delighted yesterday morning at the marathon to thank all of our medical teams, but we're travelling with a field hospital now. It looked like a scene out of M*A*S*H down there.

"They are doing a fabulous job, they're the best team around and Hungary have provided some of the very best medics, but this is the world we are now living in and this Hungary, so it is really important that was one of the areas we both talked about and the need to really address it."

For the next World Championships in Tokyo, dates have been shifted to later in the year - September 13 to 21 2025.

Climate change is already a major problem for sports organisations, and it is only going to get worse.

In the week prior to last year's Commonwealth Games in Birmingham, temperatures surpassed 40 degrees Celsius. Whether it would have been wise or safe to stage competition in that heat is debatable. It had cooled a little by the time the Games started, but sooner or later a major event is going to be faced with the prospect of an event being postponed or cancelled because it is dangerous for athletes and spectators alike.

Next year's Olympic Games in Paris is an early litmus test.

I genuinely believe Budapest could be the last World Athletics Championships for the foreseeable future staged in its usual slot of August.

Los Angeles is already due to host the earliest Olympic Games for more than a century from July 14 to 30 2028, and it seems inevitable that event organisers including the IOC will have to opt away from their traditional calendars.

I must admit I have become very sceptical of the word "sustainability", and think it is at risk of becoming meaningless given the care-free manner in which it is banned about by organisations in sport and other sectors. Planting trees to "offset carbon emissions" hardly accounts for the urgency of the problem.

In some instances perhaps belatedly, sports leaders have at least acknowledged climate change and its impact on the sporting calendar is an issue which needs to be looked at. The heat of Budapest has shown changes could be forced upon them quicker than many realise.