Last month was Earth’s hottest January on record. That might be hard for some of us in North America to believe since we’ve been bundling up against uncommonly frigid temperatures this winter. But the global record is significant for all of us.
To learn more, The Allegheny Front’s Kara Holsopple spoke with Jeff Masters, Ph.D., a meteorologist who wrote about it for Yale Climate Connections.
LISTEN to the interview
Kara Holsopple: How do we know last month was the warmest January on Earth on record? How is it measured?
Jeff Masters: You use a combination of ground-based observing sites over the land, ocean measurement sites, which include buoys over the oceans and satellites help fill in a lot of the gaps. We don’t have so many stations over the Arctic, for instance. So you have to use some satellite data there. It’s a complicated procedure. You take all these data sets and you kind of mix them all together and you have to correct for what’s called the urban heat island effect over land.
A lot of these thermometers that we have in cities are warmed by the cities themselves, so it’s not representative of the actual background temperature. When you make all these corrections. Last month was the hottest January on record.
“This past January is going to end up being one of the coolest Januarys we will ever see in the rest of our lives, even though it was the warmest January on record.”
Kara Holsopple: And why was that unexpected?
Jeff Masters: The planet’s been warming due to human-caused climate change over the past 100 or so years. So you expect more records to be set as we move forward. But we were not expecting a record of this particular month because there are a lot of natural fluctuations that occur on top of this background warming.
One of these natural patterns that help change global temperatures a few tenths of a degree away and make it more or less likely to have a record month is called the El Nino Southern Oscillation. That is a pattern of sea surface temperatures in the eastern Pacific that when they’re warmer than average, it’ll boost global temperatures. When they’re cooler than average, it’ll depress global temperatures.
The first phase of this oscillation we were in this year is the cool phase. It’s called La Nina. And that tends to depress global temperatures by about 2/10 of a degree. And when you have that little 2/10 of a degree downward bump in global temperatures because of La Nina, well, it’s very unusual to set an all-time record for the entire planet. But that’s exactly what occurred.
I don’t believe it’s ever happened before where we set a new monthly global temperature record when a La Nina event has happened. It’s always been in El Nino, the opposite phase when you have this extra warm bump in temperatures over the eastern Pacific.
Kara Holsopple: You wrote that one reason for the warmth was Earth’s surface was unusually non-reflective. What does that mean, and why does it cause warmer temperatures?
Jeff Masters: The sun will send its rays to the Earth, and a lot of that energy bounces off of the Earth. That’s called the albedo, or reflectivity, if you will. Most of it’s because of clouds, but it’s also because of how bright the surface is. If you’ve got a lot of dark land, exposed soil, it’s going to absorb a lot of sunlight, making the planet warmer.
But if you happen to have a lot of snow cover, it’s going to reflect away a lot of that light. Snow cover in the northern hemisphere in January was the fourth lowest on record. We absorb a lot more sunlight than usual because of that relatively low reflectivity.
“We’re going to see a lot more warmest Januarys on record.”
Also, we’ve been changing the planet as far as the amount of vegetation. Brightly colored vegetation has lessened. So, you’ve got more dark-colored vegetation absorbing sunlight. So this change in reflectivity was partially to credit or blame for the warmest month on record.
Kara Holsopple: What role did climate change play in this scenario?
Jeff Masters: We wouldn’t have had a warmest month on record without climate change. The steady warming of the planet means that this past January is going to end up being one of the coolest Januarys we will ever see in the rest of our lives, even though it was the warmest January on record.
Kara Holsopple: NPR reported recently that some employees at the National Oceanic and Atmospheric Administration are concerned that the Trump administration might make changes to the agency that would impact the way it collects and reports weather and atmospheric conditions.
How important is accurate information from NOAA to the U.S. and worldwide?
Jeff Masters: NOAA is critical for understanding our weather and climate system. I mean, it’s got two roles. It’s forecasting day-to-day what the weather is going to be, and then it’s also maintaining long-term climate records for forecasting what the climate is going to do. It’s really important for both of those efforts to collect accurate data.
The Trump administration has vowed to cripple climate science by defunding it. If you do that, you also risk screwing up your weather forecast because any interference with the whole system to bring in data and make good climate forecasts is the same system being used for making weather forecasts.
“A lot of concern in the climate science community that we don’t know what’s going on and that maybe we’ve underestimated global warming.”
So they’re messing at with that delicate system and potentially going to cause a lot of harm. We’re going to see worse weather forecasts as a result of this meddling. And certainly we’re going to see a very severe and long-lasting impact on climate science and climate preparedness and climate adaptation. It’s just a very sad sort of state of affairs.
Kara Holsopple: What’s the best way to explain to someone who may have experienced a pretty cold January, like I did in Pittsburgh, the significance of this warm January overall worldwide?
Jeff Masters: The U.S. had its coldest January since 1988. That’s a long period of time. I mean, 36 years. So that might give people a false sense that climate change really isn’t a big deal. Well, it was the coldest in 36 years, but was it the coldest ever? Not even close.
Back in the 70s, we had some ridiculously cold winters, in the 30s and so on. So we’re nowhere near the sort of natural variability we would expect to be seeing if the climate weren’t warming due to human-caused effects.
The fact that we’re seeing one of these unusual cold years is to be expected, and we’re going to see a lot more warmest Januarys on record, and it’s not going to be the case where the U.S. is going to escape that sort of warmth like we saw the previous winter, which was the warmest winter in U.S. history.
Kara Holsopple: Should we be concerned about this marker, or should we take it as just one more piece of information? How should we respond?
Jeff Masters: We should prepare for the climate that’s already on us, which our infrastructure is not designed to handle. I don’t know if you saw, but Kentucky just had a massive flood the last few days that killed about 11 people. That’s the sort of weather disaster we’re going to see a lot more of due to the warming climate.
When you heat up the oceans, you’re putting more water vapor in the atmosphere, which potentially leads to stronger floods. So the infrastructure we have now can’t handle that sort of situation. Our levees, dams and so on were designed for a climate that no longer exists. We need to move quickly to adapt to the new climate and move quickly to prevent the planet from warming even more.
Kara Holsopple: There were some notable records that you flagged.
Jeff Masters: Yeah, it’s interesting that oceans had their second warmest January on record, even though we had this La Nina event, which says that there’s some unusual sort of ocean heat waves going on. Those ocean heat waves are important because they affect weather patterns, the general circulation of the atmosphere, and help drive sorts of unusual, extreme events that we have trouble with.
For instance, in Northern California, they had a lot of flooding because the jet stream has been diverted to the north and has more moisture in it because of these oceanic heat waves going on off the coast of California. Similarly, an ocean heat wave helped contribute to those floods in Kentucky. A lot of moisture in the atmosphere came up off of the ocean and went inland and helped contribute to those floods. So that was the one thing that stood out for me.
Kara Holsopple: Was there anything else that I should mention or that you would want people to know about this?
Jeff Masters: It’s looking like next month, February, probably won’t set a record for warmest month on record, which is good because we don’t really understand quite so well why January was the hottest January on record. That gives us a lot of concern that maybe there are some unknown global warming factors happening that could cause a lot more warming than we’re already expecting, which is going to be extremely devastating.
So is the climate system out of whack? And we don’t understand what’s going on? It could very well be if we can continue getting a lot of these warmest months on record despite everything telling us that we shouldn’t be seeing it. So a lot of concern in the climate science community that we don’t know what’s going on and that maybe we’ve underestimated global warming.
Jeff Masters, Ph.D., is a meteorologist and former hurricane hunter. He wrote about the hottest January on record for Yale Climate Connections.
