One of the world's leading climate scientists says researchers cannot fully explain why the world has been breaking records for such extreme heat for 10 straight months, leaving the world in “uncharted territory”. He said there is a possibility.
According to Copernicus, the European Union's main climate services agency, last month was the hottest March on record, marking the 10th month in a row that it has achieved that title.
In Europe, temperatures in March were 2.12°C above the historical average, making it the second warmest March on record for the continent.
Elsewhere on Earth, temperatures were much warmer than average in Antarctica, Greenland, eastern North America, eastern Russia, Central America, parts of South America, and parts of southern Australia.
The record heatwave comes after 2023 was officially declared the hottest year on record.
NASA senior climate advisor Gavin Schmidt says climate change and the occurrence of El Niño explain a significant portion of global warming. last year's Combined with heat, and other factors, there is a thermal margin at the top that is still unexplained.
He said that's a concern.
“If we can't explain what's going on, it has a significant impact on what we can say will happen in the future,” Dr. Schmidt said.
Prediction 'failed ugly'
For about a decade, he and other climate science organizations have been predicting global temperatures over the coming year.
Each has a slightly different method for doing this.
Generally, this is done by looking at the global warming baseline the world has been in since the beginning of the year and taking known climate factors into account.
However, all of these predictions for 2023 were below the actual results, with the closest prediction still missing by nearly 0.2 degrees Celsius.
That may not sound like a big deal, but Dr. Schmidt said it's huge given the world's climate.
“Those predictions based on what happened earlier this year were spectacularly off.”
Dr. Schmidt said there is always room for error, but scientists can usually explain what happened by looking back at the data.
He said it didn't add up this time. And climate models weren't giving answers either.
“That means there's something missing in what we're thinking here,” he said.
“Either something has changed in the system and it's reacting differently than it has in the past, or there are other factors going on that we haven't considered.”
What are the possible explanations?
Scientists have investigated several different possible explanations for Earth's warmer-than-expected temperatures.
Air pollution
Among them is a theory that thanks to new international shipping regulations, the amount of air pollution around the world is lower than what climate models were accounting for.
Many aerosols act like “shades” against incoming sunlight, reflecting it back into space. Therefore, there will be fewer substances that have a warming effect.
But Dr. Schmidt said while there were some changes, it didn't seem to be enough to explain how hot it was.
“If you plug this into a model and say, 'Is that warming effect big enough to make a big difference between 2022 and 2023?' the answer is no, and as far as we know it's not.” he said.
submarine volcano
Another contributing factor is the January 2022 eruption of submarine volcanoes Hunga Tonga Hunga Ha'apai, which sent more than half of its ash and other particles into space.
Like pollution, volcanoes generally have a cooling effect.
But Tonga's volcano was different.
Because this volcano was an undersea volcano, it is thought to have released large amounts of water vapor, a powerful greenhouse gas, into the stratosphere, having a net warming effect.
Dr. Schimdt said from what we know so far, this is still a very small change overall.
“The magnitude of the change is on the order of 1/100th of a degree, which is disproportionate to the scale of what we are trying to explain,” he said.
Solar cycles and other explanations
Some look to the solar cycle as an explanation, but solar activity has reached a solar maximum, which can also affect surface temperatures.
Solar maximum refers to the period during the Sun's 11-year solar cycle when solar activity is at its highest.
But again, Dr. Schmidt said it wasn't big enough to explain what they witnessed in 2023, and that it was “featured into the calculations” anyway.
“And maybe it's just a random event that happened in Antarctica and the North Atlantic all at once, and they're not related, they're just cumulative, and the reason we haven't seen it before is because we… “It's been less than 200 years,” he said. “There's good data.”
“We are also considering such things.”
Mysteries of the climate so far
Dr. Schmidt said similar climate model conundrums have played out before.
In the early 2000s, the upward trend in surface temperatures appeared to have plateaued for more than a decade, even as greenhouse gas emissions in the atmosphere reached record levels.
This was something that climate scientists couldn't fully explain at the time, and it became known as “global warming stagnation.”
It was also frequently used by climate change skeptics as evidence that the Earth is not getting that hot.
However, subsequent research has revealed that global warming has not stopped, and is actually sinking deeper into the ocean.
Data entry, heat uptake by the ocean, natural variability, and slight modifications of observations made that clear.
Dr. Schmidt said something similar could be happening this time, and that either the climate models were missing something or the data wasn't quite right.
“Maybe we haven't characterized the Hunga Tonga volcano well enough. Or maybe we haven't tracked the emissions from China properly, because they don't necessarily give global reporters “It's not the most reliable of them all,” he said.
He said it was important to resolve the issue so that they could tell whether this was just a “moment” or the beginning of something else.
He said global temperatures in the northern hemisphere could provide some clues.
Focus on northern summer
So far, 2024 has been about as hot as expected, Schmidt said, as scientists expect global temperatures to rise in the months following the peak of El Niño.
But if everything continues as normal, the economy will cool down by June, he said.
“The key is what happens over the next few months. If things continue to be very abnormal, I think we will see systemic changes rather than temporary changes.”
In the meantime, he said he plans to revisit datasets to explain the gaps, including looking at newly available aerosol data from recently launched NASA satellites.