From our collaborating partner Living on Earth, public radio’s environmental news magazinean interview by Jenni Doering with senior scientist Jennifer Francis of the Woodwell Climate Research Center.

Scientists monitoring Earth’s climate have identified a worrying global warming trend beginning in April 2023. While climate change has been steadily warming the planet for decades, average global temperatures suddenly rose by about 0.2 degrees Celsius in 2023 and have remained high.

The temperature spike has raised concerns among climate scientists about how quickly the climate crisis is progressing as they scramble to explain Earth’s worsening fever.

Jennifer Francis studies Arctic climate and weather at the Woodwell Climate Research Center and has had her eye on the planet’s rising temperature for decades.

This interview has been edited for length and clarity.

JENNI DOERING: What is so abnormal about this temperature spike observed in recent years that is causing concern among researchers?

JENNIFER FRANCIS: There are a lot of factors that go into creating both last year 2023 and also this year, breaking temperature records for the world going back as far as we have records.

We can estimate the temperature quite far back. We’re pretty sure that last July 2023 and then again in 2024 will really be the warmest we’ve seen in many hundreds of years. So this is quite concerning, and we know what’s going on. The Earth should actually be cooling down by now, if only natural causes were at play. But we know that because we have added so many heat-trapping greenhouse gases to the atmosphere in recent decades, these heat-trapping gases are indeed trapping much more heat in the climate system than we should have now.

So what’s going on is that we’re seeing some very large and intense marine heat waves in different parts of the global ocean, and those are a result of that heat being trapped by those greenhouse gases. It’s stored in the ocean, about 90 percent of it goes into the ocean, and now we’re seeing some of that heat coming back out and into the atmosphere.

DOERING: This temperature peak is only about 0.2 degrees Celsius. That doesn’t sound like much. Why does that number mean so much to climate scientists?

FRANCIS: It doesn’t sound like much, and certainly any individual anywhere wouldn’t really notice. But in fact this is a lot for the average around the world.

If we look back at the natural fluctuations in Earth’s temperature that have occurred over thousands of years, we know that it doesn’t take much for the Earth to go from an ice age to the opposite, what we call an interglacial. this is a relatively warm period in the Earth’s natural temperature cycle. That’s only a three degree Celsius difference. So it doesn’t take many temperature changes in terms of absolute degrees Celsius, to make a huge difference in how the climate system feels, what the living part of the Earth system feels.

It can have huge consequences for things like the weather and changes in the ice and changes in plants and agriculture, because that small change in temperature globally translates into big changes in things like the atmosphere and ocean currents and things like that.

DOERING: What are some of the other theories or explanations being proposed for this recent temperature increase?

FRANCIS: This recent temperature increase is mainly caused by the increasing amounts of heat-trapping greenhouse gases we’ve been putting into the atmosphere. That’s cause number one, and the Earth should be cooling down now, but instead we’re seeing this incredibly rapid increase in global temperatures and sea surface temperatures.

Some of the other factors that play a much smaller role than the increase in greenhouse gases are the decrease in the amount of airborne particles that we put into the air from burning fossil fuels, from forest fires, from volcanoes, from pollution from the industry. There’s a decrease in the amount of those particles, and that plays a role, because those particles tend to reflect some of the incoming solar energy, and that helps because they have less of those particles, more of the energy of the sun makes it in the climate system.

An El Niño also started to develop from April 2023. El Niño is basically a pattern of ocean temperatures that we see come and go every few years, and we know that when an El Niño comes, we tend to see an increase in the Earth’s average temperature. And indeed, we saw that. But this goes far beyond what an El Niño should do.

Another possible cause, although the jury is still out, is the recent eruption of the volcano in Tonga, an archipelago in the South Pacific, which added a lot of extra water vapor and moisture to the atmosphere. Water vapor is a greenhouse gas, so this could potentially have contributed to the greenhouse effect. But it has generally been shown that this effect is also relatively small.

So it basically comes down to the fact that for decades we’ve been adding all these greenhouse gases to the atmosphere by burning mostly fossil fuels, but also by cutting down forests, removing mangrove trees from coastlines, getting rid of wetlands, all these business. natural ways that the climate system can remove things like carbon dioxide from the atmosphere and help offset the effects of those heat-trapping gases.

DOERING: It seems like things are really catching up with us.

FRANCIS: Yes, indeed. And this is no surprise.

DOERING: No surprise, but it sounds like there are climate scientists scratching their heads saying, why don’t the numbers match what we expected? What’s going on there?

FRANCIS: I would actually argue that these numbers are not out of line with what we should have expected when we look at the simulations of these very complicated computer models that we use to project what the climate system is going to do. These models fluctuate just like Earth’s real climate does, around this trend line caused by increasing greenhouse gases, and those fluctuations in the model simulations are within the range of the peak we saw last year and this year. It’s really not beyond expectations to see a spike like this. And anyway, I don’t think there’s really a big surprise here.

DOERING: Governments’ current national plans to reduce carbon emissions would still result in warming of about three degrees Celsius, far more than the Paris Climate Agreement target of 1.5 degrees Celsius. How does this recent temperature spike and this increase we see in the long term relate to the way countries should think about their climate ambition?

FRANCIS: These temperature spikes are a kind of wake-up call. And not just the temperatures, but the increase in extreme weather events that we’ve seen is increasing not only in number, but also in the amount of damage they cause, how intense they are, how much area they cover. how many areas are affected by these extreme events.

Heat waves are a big part of that, and associated with heat waves are often droughts. We have seen some very severe droughts develop and intensify, and both together are a recipe for wildfires. We have seen a large increase in the number of fires, which is a major concern, not because of the damage they cause, but also because they release many more carbon-based gases into the atmosphere, which only exacerbates the whole problem of global warming makes it worse.

We’ve seen another unprecedented flood in Spain, which follows some incredible flooding that we’ve seen in our own country, here in Asheville, North Carolina, and in Vermont and Maine and in places you normally can’t get to. consider being relatively immune to the major impacts of climate change.

So we really have to get to work here. We knew that the commitments made in Paris would not be enough. But not only are we not meeting those inadequate targets, we are falling even further behind. And so the expectation is that we will easily achieve the target of 1.5 degrees that was ambitious in Paris, but will probably move closer to three degrees. And we’ve already seen what these extreme events do, even with an average warming of 1.2 degrees Celsius. I hope this is a big wake-up call for countries and for the public who vote for leaders who make these decisions in these countries.

DOERING: You have been studying this for decades and have been sounding the alarm for quite some time. What keeps you going in this work? It must be tiring.

FRANCIS: Every day you wake up and read about another extreme weather event, because of course I study extreme weather, that’s what I pay the most attention to.

But what gives me hope to continue is knowing that my research is helping communities understand what is possible in the future, what these extreme events will do in the future, and how they could impact different areas.

I also see young people really getting excited about thinking of ways to reduce the severity of the climate crisis, not just by becoming scientists or engineers, but by, for example, going into law and changing policy. People who study art and who help the public understand it in different ways, without just listening to the news and understanding science, but reaching people through art, for example. Writers who better communicate the science, and also when an extreme event, as we saw recently, when those events happen, better translate it to the audience to understand that climate change is making these kinds of things more intense and more concerning.

I mean, there’s all kinds of ways for people to get involved. And to help make a difference. So as we go along, we can make this problem a little less bad.