CNN — The world is blasting through climate records as scientists sound the alarm: The likelihood is growing that 2023 could be the hottest year on record, and the climate crisis could be altering our weather in ways they don’t yet understand.

And they are not holding back – “extraordinary,” “terrifying” and “uncharted territory” are just a few of the ways they have described the recent spike in global temperature.

This week, the planet’s average daily temperature soared to highs unseen in modern records kept by two climate agencies in the US and Europe.

While the records are based on data that only goes back to the mid-20th century, they are “almost certainly” the warmest the planet has seen over a much longer time period – “probably going back at least 100,000 years,” according to Jennifer Francis, a senior scientist at Woodwell Climate Research Center.

And they were far from the only climate superlatives scientists have reported this year.

Last month, the world experienced its warmest June on record by a “substantial margin,” according to a report by the European Union’s Copernicus Climate Change Service.

Ocean heat has been off the charts, with surface temperatures last month reaching record levels for June. Parts of the North Atlantic have seen an “unprecedented” marine heat wave, with temperatures up to 5 degrees Celsius (9 degrees Fahrenheit) hotter than usual.

And in Antarctica, where temperatures are running well-above average for this time of year, sea ice plunged to record low levels, which scientists have linked to the warm waters off the Indian, Pacific and Atlantic Oceans.

The world is “walking into an uncharted territory,” Carlo Buontempo, the director of Copernicus, told CNN. “We have never seen anything like this in our life.”

This is what global warming looks like

While scientists say the records are alarming, most are unsurprised – though frustrated their warnings have been mostly ignored for decades.

“This is exactly what we’ve been expecting to see for a long time,” Francis told CNN.

What the world is experiencing are the impacts of global warming combined with the El Niño climate phenomenon – the arrival of which the World Meteorological Organization officially confirmed on Wednesday.

It works like this: As the world burns fossil fuels and pumps out planet-heating pollution, global temperatures are steadily warming. That leads to more intense heat waves along with a host of other impacts, such as more extreme weather, melting glaciers and rising sea levels.

Superimposed on top of these long-term warming trends are natural climate fluctuations, the most significant of which are La Niña, which has a cooling effect, and El Niño, which has a heating effect.

“So we have a naturally warm world plus the increasingly hot climate change signal,” said Friederike Otto, senior lecturer in climate science at the Grantham Institute for Climate Change and the Environment in the UK.

Andres Matamoros sits in the shade as he tries to keep cool while selling fresh fruit and cold coconuts Wednesday, June 28, 2023, in Houston. David J. Phillip/AP

While the record temperatures may have been expected, the magnitude by which some have been broken has surprised some scientists.

That this June was half a degree warmer than a typical June “is just extraordinary” for a global temperature record, said Buontempo. Usually these records – which are averages of temperatures all over the world for the entire month – are broken by a tenth or even hundredth of a degree.

Still others have been caught off guard by the nature of extreme weather events.

“We were expecting to see more and more frequent heat waves and floods and droughts around the world. But it’s the intensity of some of those events that is a bit surprising,” said Peter Stott, a science fellow in climate attribution at the UK’s Met Office.

There’s “an increasing worry that climate change is not quite as linear as we might have thought,” he told CNN. Scientists are trying to work out if weather patterns themselves might be changing, making heat waves much more intense than climate models predict.

Shaping up for the hottest year on record

While scientists cannot yet be definitive, some say this year is at least on pace to become the warmest on record.

The stars are aligning for the record to fall. Historically, global heat records tend to topple in El Niño years, and the current record-holder, 2016, coincided with a strong El Niño.

In May, a Berkeley Earth analysis put the chances of 2023 being the hottest on record at 54%. As last month turned out to be the hottest June on record, that percentage is going to increase, said Robert Rohde, a lead scientist at Berkeley Earth.

By how much remains uncertain, he told CNN, “but it’s looking more likely than not that 2023 will be a record year.”

Records are how the world keeps tabs on the climate crisis. Yet some scientists caution the attention given to these big numbers can overshadow the real-world hazards they amplify: Heat waves, floods and droughts becoming much more frequent, severe and long-lasting as the Earth heats up.

“It’s quite frustrating,” Otto said. The world gets hung up on blockbuster records but “these heat records are not exciting numbers,” she told CNN. “They mean that people and ecosystems are dying, that people are losing their livelihoods, that agricultural land will be unusable.”

Pedestrians along a road during high temperatures in Patna, Bihar, India, on Thursday, June 22, 2023. Prashanth Vishwanathan/Bloomberg/Getty Images

The human impact of extreme weather this year has already been stark.

At the end of June, Texas and the South sweltered in a triple digit heat wave with extreme humidity that made temperatures feel even hotter and made it harder for bodies to cool themselves. The heat extended to Mexico, where extreme temperatures killed at least 112 people between March and the end of June.

China has been grappling with blistering temperatures for weeks. Beijing, which is facing one of its most brutal heat waves on record, saw temperatures soar past 40 degrees Celsius (104 degrees Fahrenheit) this week.

In India, parts of the north have been struggling with unrelenting heat, while nearly half a million in the country’s northeast have been affected by severe flooding that has triggered devastating landslides which have taken lives.

“All of these kinds of extreme events are absolutely consistent with what we expect to see happening more often as we just continue to warm the globe,” Francis said.

And as El Niño strengthens, we’re likely to see more extreme weather, she added, not just in the summer but also in the winter, when El Niños have the biggest influence on Northern Hemisphere weather.

“I’d say buckle up.”

A fog cannon truck sprays water to cool citizens on Zhonghua Street in Handan, North China's Hebei province, July 6, 2023. CFOTO/Future Publishing/Getty Images

Unheeded warnings

For climate scientists, this is the “I told you so” moment they never wanted.

“This needn’t have been happening,” Stott said.

For decades, scientists have been warning about what would happen to global temperatures if the world failed to kick its fossil fuel habit and rein in planet-heating pollution. But they went unheeded, he said.

To see climate change unfold in front of us “is terrifying,” he added, because “this will just carry on getting worse and worse, and more and more extreme. So what we’re seeing now is only a foretaste of what could happen if efforts to reduce emissions aren’t successful.”

The only silver lining may be the records help raise alarm bells and persuade people to pressure political leaders to act, Otto said. “​​I hope that maybe more people will realize that this is really happening, and it’s really dangerous.”