To the enthusiasm of the public present during the World Athletics Championships, held in September in Tokyo, Japan, Armand “Mondo” Duplantis ran across the track with the pole. The applause was deafening. And Duplantis flew.
The Swedish athlete fired to confirm his dominance over one of the most technical disciplines in athletics. He achieved a new world record for the pole vault.
His 6.3 meter mark brought Duplantis’ third consecutive world title and, surprisingly, his 14th world record.
It’s a sample of what can happen in sport. Improvements in diet, technique or equipment can bring a sudden series of world records, especially in technical disciplines such as pole vaulting and cycling.
Here, small adjustments make big differences. And advances in running techniques have also brought new records in recent years.
But the men’s long jump world record has only been broken once since 1968, when American Mike Powell jumped 8.95 meters during the 1991 World Championships, also held in Tokyo.
It is possible that we have reached the limit of the long jump, a level where further improvement is impossible and the differences between athletes’ performance come down to factors related to luck, such as wind direction and speed, the quality of each person’s sleep the night before, and so on.
We designate this type of situation as stationary, that is, the general trend of average performance is unchanged.
When the system is stationary, we may wonder how often we should expect records to break due to random fluctuations. And to get an example of a stationary system that we’ve had measurements of for a long time, we can look at climate data from the pre-industrial era.
Records and rain
Imagine that we are going to investigate the annual rainfall levels in different cities around the world. In this survey, the totals for each city are independent of the others and there is no general trend in climate behavior.
The first-year rainfall total in each city, by definition, is a record. If the rain in the second year is independent of the first, on average, half of the cities will have greater rainfall than in the first year and the other half will not.
In other words, after two years, the average number of records in all cities is one plus half.
In the third year, the total must exceed the first two years to set a new record. On average, this happens in only a third of cities.
Therefore, at the end of the third year, the expected number of records is one plus half, plus a third.
And so the series continues. After a hundred years, the expected number of records per city is one, plus half, plus a third, plus a quarter… plus a hundredth.
This set of consecutive aggregated fractions is known in mathematics as a harmonic series, due to its relationship with musical harmonies.
It is present in all types of analysis, from stress tests in construction to war logistics, from reliable shuffling in card games to the number of stickers you need to buy to complete the album.
The portions we are adding get smaller and smaller, but the sum of the harmonic series is not limited to a fixed value. In fact, it continues to grow.
In mathematics, we state that this sequence is divergent. And it confirms our intuition about the records.
Even in stationary systems, new records eventually occur if we wait long enough. But as time passes, the increase in the sum of the harmonic series becomes very slow.
This would mean that the frequency of record breaking will decrease dramatically over time.
We can expect two records in the first four years, then about seven years for the next one, then about 20 years for the next one, and another 52 years for one more after that.
After a century, we would expect about five records in total, and after a thousand years, just seven.
Even in a stationary system, we still expect record breaks, but with decreasing frequency. And, turning this notion on its head, we can use record-breaking speed data to indicate whether or not a system is stationary.
Decades of climate data, for example, show that temperature records are being broken at an alarming rate. This indicates that Earth’s climate is no longer stationary and is warming rapidly, due to the effects of human activity on the planet and the emission of greenhouse gases into the atmosphere.
The rate at which heat records are broken is falling more slowly than expected and has actually increased over the past 15 years. Cold records fell much faster than in a stationary climate.
These two trends strongly indicate global warming.
Scientists use the ratio of the actual frequency of records to the expected frequency to characterize the extent of climate change. It is called the record ratio.
Over the past 15 years, the ratio of records to cold events has fallen to less than 0.5, which indicates that cold records are being broken at half the frequency expected.
On the other hand, in 2020, the record heat ratio increased to more than four. This suggests that records are being broken four times more often than we would expect in a stationary climate.
The record heat ratio reached 6.2 in 2024, which was the hottest year on record, according to the World Meteorological Organization.
What does this mean for the sport?
In athletics, we often don’t have enough data to know whether individual sports have reached steady state.
Studies argue that data on performance in elite sports, across a series of field and track events, indicates that we have already reached or are approaching peak physical performance and that we should expect, from now on, to break records less frequently.
Others argue that human performance has not yet reached its peak and will continue to improve in the future.
The number of records broken by Duplantis in recent years indicates that pole vaulting has probably not yet reached steady state. Records that last years without being broken suggest that the long jump may already be stationary or even regressing.
The women’s long jump world record is even older than the men’s. Soviet athlete Galina Chistyakova jumped 7.52 meters in 1988 and recent attempts to break this record have come nowhere near this mark.
But care must be taken not to draw too strong conclusions about the lack of records in a specific discipline.
Swimming has also seen a significant drop in record-breaking numbers following the ban on high-tech polyurethane suits in 2010.
So-called “supersuits” reduced drag and increased buoyancy. They allowed a large number of records to be broken in 2008 and 2009 when they were allowed. Some of these records remain to this day.
But the speed of record-breaking has started to increase again, indicating that progress in techniques and the pool environment may allow swimmers to continue to improve their results for some time into the future.
But sometimes new records can be due to extraordinary individuals who push the boundaries of the sport.
American swimmer Katie Ledecky, for example, broke 16 world records throughout her career. In the first half of the year, she set a new mark for the 800-meter freestyle.
And, with 14 world records to his name, it’s fair to say that Duplantis is another athlete who is setting new standards for what humans are capable of achieving.
But after the sweltering and humid Tokyo World Championships in 2025, World Athletics (formerly the International Association of Athletics Federations) president Sebastian Coe acknowledged that climate change could force the sport to reconsider its tradition of holding events in the summer.
Interestingly, Duplantis was the only one to set a new world record in Tokyo.
With 75% of athletes reporting that heat and climate change are harming their health and performance in competition, we can conclude that climate change itself will alter the frequency of breaking sports records.
At the same time, we need to celebrate the new world records that emerge. After all, the athletes who achieve this feat will have overcome all difficulties to achieve something truly special.
