Record heat of 2023 partly due to ‘mysterious’ process, says NASA scientist

It’s no secret that human activity is warming the planet, causing more frequent and intense extreme weather events and transforming ecosystems at an extraordinary rate.

But the record temperatures of 2023 have nevertheless alarmed scientists and portend new “mysterious” processes that could be underway, NASA climatologist Gavin Schmidt told AFP.

Here are excerpts from an interview with Schmidt:

Can you put into perspective what we saw in 2023?

It wasn’t just a record. It was a record that beat the previous record by a record margin.

We started with La Niña, that cool tropical Pacific phenomenon. It was still there until March. And then, in May, we started to see the development of an El Niño phenomenon, the warm phase of this cycle.

This normally affects temperatures the following year. So that would be 2024. But what we saw in 2023 was that global temperatures seemed to rise with the El Niño event, much more than ever before.

The long-term trends we understand are driven by greenhouse gases and anthropogenic effects. We hope this will continue, decade after decade, until we stop emitting greenhouse gases into the atmosphere, which we have not yet done.

But what happened in 2023 is that and more. And this “more something” is much larger than we expected, or that we cannot yet explain.

What are the main assumptions regarding this “more of something”?

There have been emails and conversations all over the world, between scientists studying this, and people are saying, “Oh, let’s look at the energy imbalances of the Earth. Let’s look at aerosols, let’s look at El Niño, what’s happening in Antarctica, in the North Atlantic. And everyone has a lot of ideas, but it doesn’t really add up.

El Niño may be enough. But if I look at all the other El Niño events that we’ve had, none of them have done this. Either this El Niño is really very special, or the atmosphere is reacting to this El Niño in a very special way. Or something else is happening. And no one has really restricted these possibilities yet.

This long-term trend remains within the bounds of what we have predicted for many years. But the details of what happened in 2023 are a bit of a mystery.

What should we expect for 2024?

It’s important to know why 2023 has been like this, because does that mean it will continue? Does this mean the impacts will start to accelerate? We do not know ! And that’s problematic.

The year 2023 did not follow old patterns. If the old patterns return and 2023 is just an incident, then 2024 will be very close to 2023. If it’s not an incident, if it’s something systematic that has changed, or is in the process of to change, then we might expect 2024 to actually be warmer. Because you have the warmth you expect, and then there’s that extra thing.

And that has implications for the weather, heat waves, intense rainfall, coastal flooding and everything else we can expect this year.

© 2024 AFP