The uptick in Arctic lightning could cause more wildfires, potentially triggering a feedback loop that releases massive amounts of carbon into the atmosphere.
- In recent years, researchers have recorded unusually high numbers of lightning strikes and wildfires in Arctic regions.
- A new study explored how increased lightning could cause a "lightning-fire-vegetation feedback loop" that could accelerate permafrost loss.
- To better monitor changing conditions in the Arctic, the researchers called for more high-quality lightning monitoring systems.
Lighting strikes in the Arctic may increase by approximately 100 percent by the end of the 21st century, according to a new study published in Nature Climate Change. If that happens, places like Alaska could suffer significantly higher rates of wildfires and permafrost loss, both of which could accelerate warming in the Arctic.
Some evidence suggests these changes are already underway. In 2015, Alaska suffered the second-most wildfires on record, burning more than 5.1 million acres across the state's northern region. Although it's difficult to measure, lightning likely started many of these fires.
Still, lightning is relatively rare in the Arctic. That's because lightning occurs when warm, moist air rises to meet cold air, which builds up electrical charge. When that charge exceeds a certain threshold, lightning strikes. Because places like Alaska have relatively cold, dry air, thunderstorms only form occasionally.
But climate change may be changing that. In 2019, the National Weather Service's office in Fairbanks, Alaska, reported an unusually high number of lightning strikes within 300 miles of the North Pole. The uptick in lighting may be no surprise, considering the Arctic is warming by more than twice the global average.
In the recent study, researchers used satellite observations and climate data to explore how increasingly frequent lightning could transform the Arctic through changes like increased wildfires and permafrost loss.
"We projected how lightning in high-latitude boreal forests and Arctic tundra regions will change across North America and Eurasia," Yang Chen, study author and research scientist in the UCI Department of Earth System Science, said in a press release. "The size of the lightning response surprised us because expected changes at mid-latitudes are much smaller."
What's especially concerning about the uptick in Arctic lightning is that it could start a "lightning-fire-vegetation feedback loop."
The researchers explained how more lightning could cause more wildfires, which would burn away many of the shrubs, mosses, and other low-lying plants covering the Arctic terrain. Without those plants covering the ground, soil temperatures would rise, making it easier for deciduous trees to grow.
That might sound like a good thing. But expanding forests could also cause regional temperatures to rise because they would absorb more sunlight than the reflective, snow-covered Arctic terrain currently does. What's more, wildfires would melt Arctic permafrost, which stores massive amounts of organic carbon.
The end result of the lightning-fire-vegetation feedback loop would be the release of carbon into the atmosphere.
Still, the variability in climate modeling and lightning monitoring makes it difficult to predict future changes with a high degree of accuracy.
"This phenomenon is very sporadic, and it's very difficult to measure accurately over long time periods," James T. Randerson, study co-author and professor in the Department of Earth System Science at the University of California, Irvine, said in the press release. "It's so rare to have lightning above the Arctic Circle."
The researchers concluded the study by calling for more high-quality lightning monitoring systems, based on the ground and in space.
"Given the large amount of permafrost soil carbon stored in northern ecosystems, this analysis highlights the importance of improving lightning monitoring in the Arctic and the need to develop better models of lightning, fire dynamics, and feedback with vegetation and soils," they wrote.
How do you get usable phosphorus into a system? A new study suggests lightning can do the trick.
- A chance discovery in suburban Illinois may change how we understand the dawn of life.
- Among other things, life needs water-soluble phosphorus, which was hard to come by 3.5 billion years back.
- This finding may imply that life has more opportunities to begin on other worlds than previously supposed.
Even the youngest child often wonders where they came from. For many scientists, a group of people known for retaining their childlike wonder, the question naturally evolves to asking how life itself originated on Earth. As is often the case when working with questions about the Earth billions of years ago, those trying to answer this one have access to a limited amount of data.
Now, a chance finding from a lightning strike in Illinois may reshape how we understand the beginnings of life on this planetand worlds beyond.
In the beginning, there were a lot of meteorite impacts and lightning strikes
Phosphorous is an important chemical for life on Earth, cells use it to help build DNA and RNA and it is required for several other important functions. There is plenty of phosphorous on Earth, but not all of it is water-soluble. It is thought that much of the phosphorus on Earth three and a half billion years ago, about the time when life first appeared, was trapped in minerals that can not dissolve in water. Given how important water is for life on Earth, this was an obstacle to the rise of life.
Until very recently, the leading theory about where most of the soluble phosphorous came from credited meteorites, many of which have small amounts of the stuff. However, this theory always had problems. The number of meteorites hitting the early Earth, while high, is thought to have fallen drastically after the event which is theorized to have created the moon. The problem gets worse over time, with fewer and fewer expected impacts as the solar system stabilized.
Additionally, meteorite impacts are often catastrophic events more often known for ending life than helping to start it. The amount of phosphorous that could arrive this way is also limited, with the heat and trauma of impact potentially vaporizing much of the stuff and leaving a pittance readily accessible in the environment.
This is where the chance finding in Illinois comes in. In 2016, a hunk of fulgurite, a clump of fused sediment created by a lightning strike, was found in Glen Ellyn, a small Chicago suburb. The sample was given to the nearby Wheaton College.
A team of researchers from the University of Leeds examined the specimen as part of an investigation into the formation of fulgurite, but were surprised to discover that it contained a large amount of schreibersite, a water-soluble phosphate mineral.
Lead author and Ph.D. candidate Benjamin Hess explained how this find might alter theories on how water-soluble phosphates came into being billions of years ago:
"Most models for how life may have formed on Earth's surface invoke meteorites which carry small amounts of schreibersite. Our work finds a relatively large amount of schreibersite in the studied fulgurite. Lightning strikes Earth frequently, implying that the phosphorus needed for the origin of life on Earth's surface does not rely solely on meteorite hits."
Their findings were published in Nature Communications and can be read in their entirety here.
Okay, this is cool and all, but how can we possibly use this information?
In addition to shedding light on the Earth's past environment and how it changed over time, this finding might also aid the search for life on other planets.
Lead author Mr. Hess speculated that the finding "also means that the formation of life on other Earth-like planets remains possible long after meteorite impacts have become rare."
This is important because, as co-author Dr. Jason Harvey explains:
"The early bombardment is a once in a solar system event. As planets reach their mass, the delivery of more phosphorus from meteors becomes negligible. Lightning, on the other hand, is not such a one-off event. If atmospheric conditions are favourable for the generation of lightning, elements essential to the formation of life can be delivered to the surface of a planet. This could mean that life could emerge on Earth-like planets at any point in time."
While these speculations presume that alien life forms will require the same substances we do to exist, the discovery of a new source of usable phosphorus is an exciting find for those interested in alien worlds and in the early geology or biology of Earth. While we might never know precisely where the phosphorous used in the first life form came from, this discovery will help to make sense of where we came from and where we might find others like us out amongst the stars.