Baker Perry is a man at the top of his field. That's not a professional judgment, it's a simple statement of fact. Perry studies weather and climate at extreme high altitudes at Appalachian State University in North Carolina. As part of his field work, he has installed meteorology stations in some truly rarefied locations, including at the Chacaltaya Observatory in Bolivia (5,160 meters, or 16,920 feet, above sea level) and atop the Quelccaya Ice Cap in Peru (5,650 meters, 18,540 feet).
Last year, Perry topped himself by co-leading a team that placed a set of weather stations on Mount Everest — including the highest-altitude station in the world, at an elevation of 8,430 meters (that's 27,650 feet, or more than 5 miles, high). Even the peak of Mount Everest remains embedded in the troposphere, the lowest layer of Earth's atmosphere, but it experiences conditions unlike those on most of the rest of the planet.
The new weather monitors are high enough to penetrate into the subtropical jet stream, offering a unique perspective on global weather patterns. They're not space stations, exactly, but they are certainly not your typical Earth stations. Perry is not your typical Earth weatherman, either. As captured in the documentary Expedition Everest (premiering tonight), he and his colleagues are inexorably drawn to the lofty environments where they and their instruments can experience parts of the environment that are otherwise almost impossible to study.
I spoke with Perry about what drives him to extremes. A lightly edited version of our conversation follows.
How did you become obsessed with ice and doing science at high altitudes?
As a kid growing up, there were two places and periods in my life that were particularly formative. The first of those was in Maine. I'd lived in Portland, Maine, for five years, and that happened to coincide with some pretty brutal winters in New England. That really piqued my interest and curiosity in snow and extreme weather.
Then, when I was 7, our family moved to the high Andes of Peru and Bolivia. My parents moved there to establish a nonprofit health NGO to improve the health care infrastructure in some of these really remote communities. I grew up at 13,000 feet on the edge of Lake Titicaca, and we took family outings up as high as 18,000 feet in the neighboring mountains. As a result, I think I’m wired a little differently. I don't like going to sit on the beach. I'd rather be up on top of a glacier at 20,000 feet.
When was the first time that you went up Mount Everest?
I traveled to the Khumbu region in 1999. My father was based in Bangladesh, working with a child health project there, and I had the opportunity to go visit him over Christmas break. I had written a paper in graduate school on glacial-lake outburst floods in the region, and I was like, “Hey, this is a perfect opportunity to visit some of these lakes I've been studying.” But I hadn’t been back until January 2019; then, last May was my first expedition on Everest going above boot camp.
How has climate affected the high-mountain locations where you do your research?
There's one location in particular, a glacier lake in Bolivia that's called Laguna Glaciar, which just means Glacier Lake. In 1999, we took students there from Appalachian State University. It was a massive glacier with a huge glacier front. Massive pieces were calving off into the lake from time to time.
I didn't have a chance to go back to this site until 2017. The glacier had basically completely fragmented; there was no calving front into the lake. Seeing this happen just over my professional lifetime — and I’m not that old! — was pretty sobering. It was a very different kind of moment than looking at data and statistics in a chart, or seeing pairs of repeat photos from other mountain regions around the world.
Tell me about your 2019 trip back to Mount Everest, the one covered in the new National Geographic Expedition Everest documentary.
The documentary covers a time period from about mid-April until late May of 2019. It was a massive expedition. I think we were calling it the most comprehensive scientific expedition ever to Mount Everest. There was also a whole media team, which was almost always at least four to six, sometimes as many as eight, following us around.
I'm a little shy initially with the media, and Tom [Tom Matthews of Loughborough University] and I in particular kept coming up with excuses at the beginning as to why we had to go on ahead, or not wait for them to do their shots. We had to work on the weather stations and work on the communication.
What is unique about the science you can do up high, almost on the edge of space?
Most of my work has been focused on installing weather stations in some of the highest places in the Andes, and now in the Himalayas and Everest. A lot of that was being driven by my interest in precipitation: understanding how much it's snowing or precipitating on these glacier surfaces, and what the timing is in terms of afternoon or night, and seasonal patterns. How it affects the whole accumulation, or what we call the glacier mass balance.
Fundamentally, what we're learning from these stations in the Andes and in the Himalayas is just how the atmosphere works up at these extreme elevations. It's one thing to have measurements from weather balloons or aircraft or satellites, but those don't always capture what is actually happening. These surface measurements really hadn't been made, with very few exceptions. It's hard to accurately measure precipitation even at low elevation, but up high on these glacier surfaces, it’s really challenging.
How do you even get those measurements? Don’t your instruments get buried?
In Peru, we have a station on the Quelccaya Ice Cap at 18,500 feet. We initially put all the sensors as much as 3 meters above the snow surface. When we went back the next year, it was almost buried, and we had to dig everything out and then raise it up again.
The instruments run on multiple solar panels and lead-acid batteries. They got buried, and that killed the battery, and so we had to replace the battery. There's lots of trial and error.
What have you learned about climate from your mountaintop data?
One of the amazing things that we see in the data from the stations is just how intense the solar radiation is up there. At times, the intensity of solar radiation we're measuring is higher than what we expect at the top of the atmosphere [based on satellite measurements], because of the multiple reflectance that occurs from clouds and from adjacent snow-covered peaks.
Because the solar radiation is so intense, melting can occur on those snow- and ice-covered surfaces even when the air temperature is well below freezing. That's a really important finding that leads us to believe that the glaciers in the region may actually be a little more susceptible than previously thought to melting and to loss.
We hope that the data that we're collecting will help to improve the glacier melt models. In many parts of the world, they're just based on a simple temperature threshold; it's critical to include these other processes as well, since a melt can occur even when temperatures are below freezing.
You’re also using your data to help out explorers on Mount Everest and other mountains, right?
The data we've collected have already allowed us to demonstrate how weather forecasts [for climbers] can be improved. Wind speed is the biggest single meteorological factor that influences climbing success on Everest.
When the winds are above a certain threshold — about 20 meters per second, or 45 mph — the success rate [of mountain climbs] goes way, way down, looking at past expeditions. It becomes life-threatening. People actually get picked up and blown off the mountain.
Yeah, what we're finding with some of these analyses is that some of the disappearances [of climbers on Everest], some of which have been highly publicized over the years, have coincided with periods of high winds. These are people who, in many cases, bodies have never been recovered, or the exact cause of their disappearance is unknown. We can reconstruct the timing to show that there were some very windy periods up there.
What about longer-term climate trends? How do those high-altitude measurements help us understand the ways our planet is changing?
For one thing, there’s a connection to larger-scale patterns, the subtropical jet stream, for example. What's going to be really exciting is when we start to get the data coming back from the highest ice core in the world [on Everest], which is currently delayed because of COVID-19.
The labs are shut down for now. But it's going to be very interesting to try to understand the ice core record in the context of the weather observations that we now have for one year up there, and to provide a bit more context in that.
What will you be looking for?
We still don't know what the exact age of the core is, so that's part of what we're waiting on results for. Hopefully, the top of the core is not terribly old, and then we can use the observations from the weather station to provide a context for that upper layer. Providing that context can allow inferences to be made as to what we're seeing in that upper portion of the core.
Then, going back in time, the statistical relationships in those inferences can be used to reconstruct the past climate. I'm eager to see what we can do working with our colleagues from the University of Maine — Paul Mayewski in particular and his group — to see what we can do there.
Our mapping team has also been working on the Khumbu glacier [below Everest]. The reconstructions of it are absolutely incredible — some of the finest-resolution data of any glacier ever captured with drone helicopter lidar work.
You’ve been looking into the effects of high-altitude climate change on the people who rely on mountain snow and ice for their drinking water. What are you finding?
As glaciers have retreated across the Himalayas, over the short term there's an increase in runoff and melt water coming off of those because of the melt. Longer-term, as some of these glaciers disappear, or stabilize at smaller volumes at higher elevations, there's less runoff. That really creates a challenge for adaptation, because communities downstream may initially adapt to the increase in runoff. Then, that resource disappears, in some cases, the runoff decreases, and there's this new reality. That may coincide with higher temperatures, leading to more evaporation and transpiration, and also to more variable precipitation patterns.
Can you see the human impacts of those changes?
In the Khumbu region, the monsoon rains have normally arrived by mid-June. Well, that didn't happen until early July last year, so June of 2019 was the driest June on record going back to 1949. We were hearing stories from our team members in Phortse, which is the community at 12,000 feet, that their spring water supplies were nearly dry in May.
In the United States, we know climate change is occurring, and there's some impacts that we feel from time to time. But you go to these places in the high Himalayas and the Andes, and it's not some abstract idea. This is taking place in people's lifetimes and having direct impacts on their livelihoods. It's evident in the volume of snow and ice that's present there, and it's much more in your face.
Now that you have weather stations on top of Mount Everest, at the top of the world, what’s the next frontier in studying high-altitude weather and climate?
We need a long-term, sustainable plan to make sure the stations are able to operate in a way that doesn’t require myself or my colleague Tom to go back every year. For the lower stations that we set up at Phortse and at base camp, we envision those lasting 20 years or longer. To have a record of more than five to 10 years at these locations would be phenomenal.
There are a few other places in the world that are also critically important for understanding glaciers and climate. I'm hoping to set up weather stations in the Karakoram mountains in Pakistan, at the headwaters of the Indus River. Other sites that fascinate me are Denali in Alaska and the southern Andes in Patagonia, where there are huge extremes in wind and especially precipitation.
Astronauts often talk about the "overview effect" that they get when they look at Earth from orbit. Do you get a similar kind of perspective change at the top of Mount Everest?
Yeah, there are definitely moments like that, especially at the balcony. I can recall when we were trying to build this weather station and set it up while the sun was rising. I was looking out at the highest mountains in the world, really at the top of the atmosphere — and there was the sunrise. The clouds were particularly stunning that morning.
That’s a moment that'll stay with me for a long time.
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