2020 will be remembered for many reasons in the United States – among them the emergence of the COVID-19 pandemic, a turbulent political cycle and nationwide protests against racial injustice. But, the year has also etched itself into the global record books. NASA says 2020 tied 2016 for the hottest year on record.
WAMC's Jim Levulis spoke with Dr. Gavin Schmidt, Director of NASA’s Goddard Institute for Space Studies, about his agency’s findings.
Schmidt: So it's way up there. 2020 was tied for the warmest year on record along with 2016, which you might recall was affected by a big El Nino event, the start of that year, we didn't have that in 2020. So it's all the more remarkable that there we’re matching those temperatures already.
Levulis: You note in your report that whether one year is a record is not really that important, but rather, it's the long-term trends that are key. So what is the trend that the earth is currently on when it comes to global temperatures?
Schmidt: So the trend that we're on is up. The last seven years have been the seven warmest years, we've warmed about two degrees Fahrenheit a little bit more than that, since the late 19th century. And we are continuing to warm at about half a degree per decade. And so that's very concerning. And the impacts of that already being seen. We're seeing it in sea level, we're seeing it in intense precipitation, heat waves, fires, more intense drought, you know, these are impacts that are noticeable now, to many, just kind of casual observers.
Levulis: And the COVID-19 pandemic during 2020 and in 2021, obviously resulted in the restricting of travel and many sectors of the economy. So did that have an impact on global temperatures in 2020?
Schmidt: So that's a great question. We’ve seen a decrease in the amount of carbon dioxide emissions, maybe about 10% last year, but we're still adding way more carbon dioxide into the atmosphere than the planet can deal with. So the concentrations of carbon dioxide in the atmosphere still continued to go up. So that didn't help very much in terms of climate. But there were other impacts there. So not driving, not flying, changed the amount of other pollutants that we're putting into the air, particularly nitrous oxides and a little bit of sulfur dioxide. Those create smog and particles in the atmosphere and taking those away actually may have warmed the climate a very small amount. But we're having noticeable impacts on the climate. And we can see these things from satellites, even if not quite in the temperature data directly.
Levulis: And you mentioned the El Nino earlier. In your report, you note that the largest source of year-to-year variability in global temperatures typically comes from the El Nino, which is naturally occurring, is there any indication that warming caused by human activities is impacting the El Nino?
Schmidt: That's very much an open question. Now, people are looking at that. But one of the problems is the El Nino and La Nina, kind of a cool cousin, it's kind of chaotic. And so it's very hard to see whether there's a trend or there's a shift in how they're working. We think that there should be, might be a really getting a very precise idea of how that's happening has been a big challenge for climate scientists for decades now. So the jury's still out on that question.
Levulis: And you mentioned that the El Nino didn't have much of an impact in 2020, if I'm understanding you correctly, so what might 2021 have in store?
Schmidt: So right now we've started going into a La Nina event. And you can see that kind of clearly in the satellite and in the ocean data. For November and December, you can see this very clear, cool pattern along the equator in the tropics. And so that generally means that the year following is going to be a little bit cooler. So we're not expecting a record warm year in 2021. But it's still going to be a top five year. It's still going to be more than two degrees Fahrenheit above the baseline. And so we get a little bit of a respite, but we're not getting a respite from the long term trends and they're here to stay unfortunately.
Levulis: In your mind, what would need to be done to find that respite?
Schmidt: So the long-term trends are being driven by the increases in greenhouse gases, chief among those is carbon dioxide and methane and a few others. To change that trajectory, we need to reduce emissions. And that's a big challenge. There are many efforts to do so. And they haven't been that successful so far. But you know, that's where we need to go. But the challenge is large and involves, you know, almost every sector of what we do as a society from power generation to heating buildings to how we grow our food.