Global warming is NOT surging, scientists say – despite record-breaking temperatures

From the hottest day in Britain to the hottest year on record globally, there are undoubtedly some worrying temperature records that have been broken in recent years.

Many people think that the rate of global warming has accelerated or ‘expanded’ dramatically over the past fifteen years – and is a cause of more extreme weather.

But a new study says there is no statistical evidence for this so-called ‘wave’ or ‘jump’.

Researchers looked at long-term global surface temperatures since records began in 1850 and found no evidence of an increase since the 1970s.

While academics agree that man-made global warming is happening, they say it is not statistically “increasing” as some claim.

In recent years we have seen record-breaking temperatures and heatwaves worldwide, including the UK’s hottest record set in July 2022.

Last year was officially the warmest year since global records began in 1850, while the ten warmest years in the historical record have all occurred in the past decade (2014-2023).

However, the new study found a lack of statistical evidence for an increased warming rate that could be defined as a wave.

“Our concern with the current discussion around the presence of a ‘wave’ is that there was no rigorous statistical treatment or evidence,” said co-author Professor Rebecca Killick, a statistician at Lancaster University.

‘We decided to tackle this head-on, using all the commonly used statistical approaches and comparing their results.’

The team says that a “current debate centers on whether there has been a recent sharp increase or acceleration of warming.”

To find out more, Professor Killick and partners from UC Santa Cruz in the US studied the ‘global mean surface temperature’ (GMST),

GMST is simply the average temperature of the Earth’s surface – and a metric that is extensively studied to monitor climate change.

It is usually recorded by weather balloons, radars, ships, buoys and satellites, both over the oceans and on land.

The experts looked at GMST from four major agencies that have tracked the average temperature of the Earth’s surface – NASA, National Oceanic and Atmospheric Association (NOAA), Berkeley and Britain’s HadCRUT – since 1850.

Although GMST increases in the long term, it tends to fluctuate in the short term due to natural phenomena – such as large volcanic eruptions and the El Niño Southern Oscillation.

Therefore, the team considered a warming wave to be statistically detectable if it exceeded and persisted at a level above these temporary fluctuations for a long period of time.

‘Imagine temperature records displayed on a graph: a small change in slope would take longer to detect as significant, while a large change would be apparent more quickly,’ says Professor Killick.

After accounting for short-term fluctuations in the GMST, a warming wave after 1970 “could not be reliably detected,” the team found.

“No change in the rate of warming after the 1970s is observed, despite the record temperatures observed in 2023,” they write in their paper, published in Nature communication Earth and environment.

The team emphasizes that a wave of global warming may be underway, but it is not yet detectable.

“Of course, it is still possible that global warming is accelerating,” said lead author Claudie Beaulieu, a professor of ocean sciences at UC Santa Cruz.

“But we found that the magnitude of the acceleration is statistically too small, or there isn’t enough data yet to detect it robustly.”

Professor Beaulieu agreed that the Earth is the warmest it has ever been since records began, because of human activities.

She said: ‘To be clear, our analysis shows continued warming; But if there is an acceleration of global warming, we cannot yet detect it statistically.’

Commenting on the findings, Richard Allan, professor of climate science at the University of Reading, suggested there is only one line of evidence was eligible for the study.

“In fact, when all lines of evidence are examined closely, it is clear that climate change is accelerating and continuing at a fairly steady pace,” says Professor Allan, who was not part of the research team.

“Stopping global warming by stabilizing the planet’s climate and limiting further damage from worsening extreme weather and rising sea levels will only be possible through rapid and massive cuts in greenhouse gas emissions.”

Dr. Kevin Collins, senior lecturer in environment and systems at the Open University, said there was a “very real danger” of the findings being misinterpreted.

“Given that many people and places have experienced record temperatures around the world year after year over the past decade, it is very human to assume that global warming is accelerating or ‘increasing,'” said Dr. Collins, who was also not at the research was involved.

‘However, from an authoritative statistical analysis of temperature increases since 1970, this study concludes that there has not yet been a noticeable increase.

‘Instead, the results suggest that global warming is occurring at a steady state.

‘However, as the authors acknowledge, this may be because the magnitude of any acceleration is statistically too small, or because there is simply not enough data to detect an increase over the past decade.’

In other words, it is too early to say whether the past decade – the warmest on record – represents a ‘jump’ in the warming trend.

“By 2035 or 2040, we can look back and see that there has been a fundamental shift in the warming trend from 2015.”