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VOL. 104 | NO. 3
MARCH 2023
Converging Science
and Grand Challenges
DART’s Smashing Success
EEAGER Beavers
CHRONICLING
CLIMATE IN
Rings
and
Rocks
Scientists find fresh approaches
to familiar data.
FROM THE EDITOR
Editor in Chief
Caryl-Sue Micalizio, Eos_EIC@agu.org
New Discoveries in Old Records
Editorial
Managing Editor Jennifer Schmidt
Senior Science Editor Timothy Oleson
S
Associate Editor Jason P. Dinh
Senior Science Reporter Kimberly M. S. Cartier
cientists have long known that dendrochronology and News and Features Writer Jenessa Duncombe
geochemistry offer substantial clues about our planet’s
past. In this month’s Eos, we take a look at how inno- Production & Design
vative techniques and converging sciences are helping to yield Assistant Director, Operations Faith A. Ishii
Senior Production and Analytics Specialist Anaise Aristide
new discoveries in old records. Assistant Director, Design & Branding Beth Bagley
So what can those records tell us about our past, present, Program Manager, Brand Production Valerie Friedman
Senior Graphic Designer J. Henry Pereira
and future climate? Here are some fascinating facts:
Multimedia Graphic Designer Mary Heinrichs
1. New York City has a forest of old-growth timbers in its
rafters, with some beams dating as far back as the early 1500s. Strategic Communications and Marketing
Timbers of trees felled from the Adirondacks to Alabama tell Vice President Joshua Weinberg
Publisher Heather Goss
a story of droughts and deluges that have “great potential to
Assistant Director, Marketing & Advertising Liz Zipse
support evidence-based decisionmaking in the city, in terms Senior Marketing Specialist Camila Rico
of both cultural heritage and climate risk.” Jenessa Duncombe
explores the climate database hidden in the Big Apple’s attic in “Finding Climate History in Advertising
the Rafters of New York City Buildings” on page 24. Display Advertising Steve West
steve@mediawestinc.com
2. Following the Chicxulub impact event, nonavian dinosaurs faced a future that was Recruitment Advertising recruitmentsales@wiley.com
either bad or worse: quick death in a fiery inferno or prolonged starvation in the decades-long
impact winter that followed. Turn to “A Post-Impact Deep Freeze for Dinosaurs” on page 30, Science Advisers
Geodesy Surendra Adhikari
in which Aubrey Zerkle shares how she and her team examined sulfur isotopes from Chicxu- Hydrology José Luis Arumi
lub crater and identified long-term effects of “the single greatest unavoidable threat to life Ocean Sciences Clark Alexander
on Earth”—an asteroid impact. Natural Hazards Paula R. Buchanan
GeoHealth Helena Chapman
3. Colombia’s known geological history is well preserved in half a dozen databases, but Atmospheric and Space Electricity Kenneth L. Cummins
these resources are akin to boxes of unsorted puzzle pieces—each offering valuable, yet ulti- Tectonophysics Rebecca Dorsey
Education Kyle Fredrick
mately unassembled, fragments. In “A Puzzle Mat for Assembling Colombia’s Geologic His-
Diversity and Inclusion Sapóoq’is Wíit’as Ciarra Greene
tory” (p. 36), Carolina Ortiz-Guerrero tells the tale of early-career researchers who compiled Space Physics and Aeronomy Jingnan Guo
the new Colombian Geochronological Database to contextualize the data, make it accessible, Hydrology Caitlyn Hall
Science and Society Sara Hughes
and identify missing pieces. Planetary Sciences James T. Keane
All three exercises in reevaluating climate records are transdisciplinary by nature, involv- Cryosphere Michalea King
ing science and commerce, history and chemistry, data infrastructure and geology. They are Seismology Ved Lekic
Mineral and Rock Physics Jie “Jackie” Li
exemplar projects in “Converging Toward Solutions to Grand Challenges,” a theme Ryan Near-Surface Geophysics Dan R. Glaser
McGranaghan, Adam Kellerman, and Mark Olson explore in their opinion (p. 20), which is Volcanology, Geochemistry, and Petrology Michelle Jean Muth
Atmospheric Sciences Vaishali Naik
itself concerned with the future of the U.S. power grid system.
Study of the Earth’s Deep Interior Rita Parai
As narrowly defined analyses of rings and rocks give way to more nuanced ebbs and flows Earth and Space Science Informatics Sudhir Raj Shrestha
of contextual data, Eos is proud to share how the geosciences are primed to address quanda- Global Environmental Change Yangyang Xu
Geomagnetism, Paleomagnetism,
ries of the past and challenges of the future. and Electromagnetism Nick Swanson-Hysell
Nonlinear Geophysics Daniele Telloni
Paleoceanography and Paleoclimatology Kaustubh Thirumalai
Earth and Planetary Surface Processes Desiree Tullos
Biogeosciences Merritt Turetsky
History of Geophysics Roger Turner
Global Environmental Change Yangyang Xu
Caryl-Sue Micalizio, Editor in Chief
©2023. AGU. All Rights Reserved. Material in this issue may be photocopied by
individual scientists for research or classroom use. Permission is also granted to use
short quotes, figures, and tables for publication in scientific books and journals. For
permission for any other uses, contact the AGU Publications Office.
Eos: Science News by AGU (ISSN 0096-3941) is published monthly except December
by the American Geophysical Union, 2000 Florida Ave., NW, Washington, DC 20009,
USA. Periodical Class postage paid at Washington, D.C., and at additional mailing
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Submit your article proposal or suggest a news story to Eos at bit.ly/Eos-proposal.
Views expressed in this publication do not necessarily reflect official positions
of AGU unless expressly stated.
Randy Fiser, Executive Director/CEO
SCIENCE NEWS BY AGU // Eos.org 1
CONTENT
30
24 36
Features
24 Finding Climate History 30 A Post-Impact Deep Freeze
in the Rafters of New York for Dinosaurs
City Buildings By Aubrey Zerkle
By Jenessa Duncombe Animals acclimated to the warm Cretaceous weren’t so
chill in Chicxulub’s frigid aftermath.
New York City’s historic buildings are vaults of climate
data. Some scientists are on a mission to keep those
records out of the landfill.
36 A Puzzle Mat for Assembling
Colombia’s Geologic History
On the Cover By Carolina Ortiz-Guerrero
A 200-year-old oak tree was removed from a residential yard
Early-career researchers compiled available data on
in De Pere, Wis., due to a split extending to the ground. Credit:
Colombia’s geochronology into a single accessible
Steven W. Lepak
source.
2 Eos // MARCH 2023
CONTENT
6 19
8 43
Columns
From the Editor Opinion
1 New Discoveries in Old Records 20 Converging Toward Solutions to Grand Challenges
News Research Spotlight
5 Arctic Sediments, a Peruvian Volcano, and a Russian 41 Long-Lived Lakes Reveal a History of Water on Mars
Famine 42 When the Aral Sea Dried Up, Central Asia Became
6 NASA’s Double Asteroid Redirection Test Is a Smashing Dustier | If There Is Phosphine on Venus, There
Success Isn’t Much
8 Glacial Ice Offers Polar Bears a Precarious Climate 43 Mapping Street-Level Pollution Estimates to Reveal
Refuge Safer Routes
9 Scientists EEAGER-ly Track Beavers Across the Western 44 Fluid Dynamics of Tiny, Ancient Marine Animals |
United States Tracking Water in the Tongan Volcano’s Massive
11 Drones Make Weather Prediction at the Poles Easier Eruption Plume
12 New Crowdsourced Science Project Will Study Sprites
13 Stories Scribed on Palm Leaves Help Scientists
Understand Ancient Eruption
Editors’ Highlights
15 Were Impressionist Masters Painting a Polluted 45 Long-Lasting Impacts of Nuclear War on the Ocean
Reality?
16 Ancient Nile Tributary May Have Aided Pyramid Positions Available
Construction
46 Current job openings in the Earth and space sciences
18 Geohazard Education Trainings Foster Resilience
Postcards from the Field
in Rural Alaska
19 A Day in the Life Used to Be 17 Hours
48 Greetings from the White River!
AmericanGeophysicalUnion @AGU_Eos company/american-geophysical-union AGUvideos americangeophysicalunion americangeophysicalunion
SCIENCE NEWS BY AGU // Eos.org 3
NEWS
Arctic Sediments, a Peruvian Volcano,
and a Russian Famine
O
n 19 February 1600, the Huaynaputina
volcano in southern Peru erupted, in
the largest such event ever recorded
in South America. The eruption column was
32 kilometers tall, and an estimated 13 cubic
kilometers of magma were released.
A multidisciplinary team recently pub-
lished a study in Quaternary Research (bit.ly/
volcano-famine) supporting the idea that a
year after the Huaynaputina eruption, its cli-
mate effects led to global cooling and cata-
strophic crop failures in northern Europe. In
turn, these food shortages contributed to the
Great Famine that killed a third of Russia’s
population.
Sediment Cores from an Arctic
Archipelago
In 2015 and 2017, a group of students, doctoral
candidates, and professors from different
disciplines participated in an expedition to
Russia’s Novaya Zemlya archipelago, one of In Peru, the eruption of the Huaynaputina volcano destroyed nearby agricultural terraces like this one. Credit:
the least explored regions in the Arctic and a Jersy Mariño
location that can be accessed only by ship.
The expedition collected sediment core
samples from seven fjords in the archipelago.
All researchers had access to a workstation Within the cores, the team found a sharp into the atmosphere. These volcanic gases,
and laboratory on board the R/V Akademik decrease in sedimentation rates, grain size, which damage foliage and discourage plant
Mstislav Keldysh, where the samples were cut and biogenic remains of marine organisms growth, took as long as a year to reach north-
in half lengthwise. One half was saved for starting in the 17th century. These results ern Europe.
scanning at an onshore laboratory, and the suggest a sudden onset of colder weather. The “coolness of the [1601] summer was a
other half was analyzed on board the ship for result of these volcanic aerosols high in the
factors such as grain size, mineralogy, chem- Global Cooling in Historical Records stratosphere…and that led to extreme har-
istry, and biology, explained Valeriy Rusakov, The team studied historical documents as vest loss,” said Huhtamaa. As an example of
lead author of the study and a geologist at the well as scientific samples and found that that loss, she pointed to church records from
Vernadsky Institute of Geochemistry and the “drastic decrease in sedimentation in the the municipality of Pöytyä, Finland, which
Analytical Chemistry at the Russian Academy fjords” of Novaya Zemlya coincided with document that of the 142.7 barrels of rye
of Sciences. written records of both the 1600 Huayna seeds sowed in 1601, only 1 barrel could be
putina eruption and extreme cold weather
around the world, from crop failures in north-
ern Europe to a 2-week change in the blossom
time of peach trees in China.
This cooling “led to the Great Famine of
1601–1603, which led to the change of ruling
dynasties in Russia,” said Rusakov. (The
dynasty that emerged, the Romanov, led Rus-
sia until 1917.)
Heli Huhtamaa, an assistant professor at
the University of Bern in Switzerland, was
not involved with the new research but con-
cured with its general findings. According to
Researchers aboard R/V Akademik Mstislavt Keldysh her, the Huaynaputina volcanic eruption is
made an expedition to the Russian archipelago of considered to be the most likely culprit of the
Novaya Zemlya in 2017 to extract sediment cores cold weather experienced in 1601 because the Scientists on the 2017 expedition study sediment
from fjords. Credit: Valeriy Rusakov eruption released large quantities of sulfur cores from Novaya Zemlya. Credit: Valeriy Rusakov
SCIENCE NEWS BY AGU // Eos.org 5
NEWS
harvested. (A barrel is equivalent to about
146.5 liters.)
NASA’s Double Asteroid Redirection
“Historical reconstructions of unrecog-
nized climatic processes can be extremely
Test Is a Smashing Success
R
important for understanding the role of the
nonhuman world in human affairs,” said ocks from space have walloped Earth spacecraft they’d spent well over a decade
Andy Bruno, an environmental historian and for eons, and it’s only a matter of time designing, building, and testing.
professor at Northern Illinois University. But until our planet lands yet again in The launch went smoothly, and DART soon
he warned that we should be wary of “claims the crosshairs of a very large asteroid. But entered orbit around the Sun. For roughly
that reduce any complicated historical event unlike other forms of life—here’s looking 10 months, the spacecraft largely tracked the
to a sole climate trigger.” at you, dinosaurs—humans have a fighting orbit of Earth, essentially waiting to catch up
The eruption of Huaynaputina and shifts in chance of altering our cosmic destiny. At to the D
idymos-Dimorphos asteroid system,
glacial dynamics in the Arctic played a role in AGU’s Fall Meeting 2022, researchers pre- which orbits the Sun between Earth and Mars.
the Great Famine in Russia, Bruno said, but sented a slate of new results from NASA’s “We stayed close to Earth the entire time and
were far from the only factors. The extended Double Asteroid Redirection Test (DART) mis- just caught up with the Didymos system at its
crop failures exacerbated an ongoing political sion, the first demonstration of asteroid closest approach to Earth,” said Elena Adams,
and social conflict known as the Time of Trou- deflection. DART mission systems engineer at the Johns
Hopkins University Applied Physics Labora-
Peering at an Orbit tory (APL) in Laurel, Md.
DART’s target, the D idymos-Dimorphos
Approaching the Unknown
“Historical reconstructions asteroid system, was first discovered in the
mid-1990s. Astronomers back then spotted It was only around July 2022 that DART’s
of unrecognized climatic only its larger member, Didymos, which is onboard camera—the Didymos Reconnais-
processes can be roughly 800 meters (half a mile) in diameter.
It wasn’t until 2003 that scientists realized
sance and Asteroid Camera for Optical navi-
gation (DRACO)—caught its first glimpse of
extremely important that a much smaller body, dubbed Dimor Didymos. But Dimorphos wouldn’t come into
for understanding the role
phos, was also present. Dimorphos is about view until much, much later: Just 1 hour
one fifth the size of Didymos, and its orbit before impact, at a distance of roughly 25,000
of the nonhuman world takes it in front of and behind Didymos as kilometers, the tiny moonlet was still a mere
seen from Earth. That’s serendipitous, 2 pixels across in DRACO images.
in human affairs.” because by monitoring how the brightness of “We didn’t see Dimorphos until late in the
the D idymos-Dimorphos asteroid system game,” said Adams. To prepare for the uncer-
varies over time, scientists were able to tainties of striking a body they knew virtu-
determine precisely how long it took Dimor- ally nothing about, DART team members
bles, which lasted until the establishment of phos to complete an orbit: 11 hours and ran thousands of Monte Carlo simulations
the Romanov dynasty in 1613. 55 minutes. beforehand, in which they varied the moon-
For Jersy Mariño, research that explores “We needed to understand the D idymos- let’s size, shape, albedo, and a slew of other
the connection between the Huaynaputina Dimorphos system before we changed it,” parameters.
eruption and historical events around the said Cristina Thomas, a planetary scientist at
world is essential for recognizing the “cul- Northern Arizona University in Flagstaff, at
tural and geological value” of this volcano and AGU’s Fall Meeting 2022.
the importance of studying it. Mariño is a
geologist from the Peruvian Geological, Min-
The primary goals of the DART mission
were simple, at least in concept: to hit Dimor-
“We needed to understand
ing, and Metallurgical Institute who has con- phos with the roughly 570-kilogram (half- the Didymos-Dimorphos
system before we changed
ducted extensive research on the geological ton) DART spacecraft to significantly alter the
history and risk posed by this and other vol- orbital period of Dimorphos around Didymos,
canoes in southern Peru. to measure that change, and to characterize it.”
During a recent expedition to Huayna- the physics of the impact. If successful, it
putina, Mariño and his team found evidence would be the first demonstration of deflecting
of six towns and several terraces used for an asteroid using so-called kinetic impactor
agriculture in the 17th century that were technology. (In 2005, another NASA mission,
completely buried during the 1600 eruption. Deep Impact, tested kinetic impactor tech- The DART spacecraft successfully hit
(The volcano has not erupted since then.) nology with a comet.) Dimorphos on 26 September 2022. The event
The scientists recommended that the On 23 November 2021, a Falcon 9 rocket was recorded by a cadre of Earth-based tele-
Peruvian government start archaeological lifted off from California’s Vandenberg Space scopes and also the Light Italian Cubesat
expeditions as soon as possible. Force Base. By then, the SpaceX-designed for Imaging of Asteroids (L ICIACube), a
rocket had notched more than 100 successful b riefcase-sized spacecraft carrying two
launches, but for members of the DART mis- cameras that launched with DART and was
By Santiago Flórez (@rflorezsantiago), Science sion, the event was anything but ordinary: released from the spacecraft 15 days prior to
Writer Nestled within the rocket’s nose cone was the impact.
6 Eos // MARCH 2023
NEWS
This illustration of NASA’s Double Asteroid Redirection Test (DART) spacecraft (foreground) and the Italian Space Agency’s LICIACube depicts them just prior to impact at the
Didymos-Dimorphos binary system on 26 September 2022. Credit: NASA/Johns Hopkins APL/Steve Gribben
A Serendipitous Boost million kilograms (1,100 U.S. tons) of material when it comes to binary asteroids, but it’s
Researchers had calculated that the impact, were blasted off the asteroid by the impact. never been confirmed. Thomas, leader of the
which occurred roughly head-on, would That’s enough debris to fill several rail cars, DART Observations Working Group, pre-
shorten Dimorphos’s orbital period by just said Andy Rivkin, DART investigation team sented new results on the subject at the press
under 10 minutes. That was assuming the lead at APL, at a press conference at the Fall conference at the Fall Meeting. She shared
simplest scenario, in which no ejecta is pro- Meeting (bit.ly/AGU22-DART). near-infrared spectra of the binary asteroid
duced, said Andy Cheng, DART investigation system that astronomers had collected both
team lead at APL, at a press conference. Follow the Debris before and after impact using a NASA tele-
“The amount of momentum that you put Of particular interest, the ejecta shed by scope in Hawaii.
in the target is exactly equal to the momen- Dimorphos has remained in distinctly more Observations obtained prior to impact
tum that the spacecraft came in with.” But plumelike configurations than the debris (when the overwhelming majority of the sun-
if ejecta flies off the asteroid after impact, shed by comet 9P/Tempel 1 when NASA’s light reflected off the asteroid system came
physics dictates that the asteroid can get an Deep Impact spacecraft intentionally crashed from Didymos) and after impact (when the
extra boost, said Cheng. “You end up with a into it in 2005. “The Dimorphos ejecta has a debris shed by Dimorphos was responsible for
bigger deflection.” lot of morphological features,” said Jian- more than two thirds of the reflected light)
That’s good news when it comes to pushing Yang Li, a planetary scientist at the Planetary revealed very similar spectra, with character-
a potentially harmful space rock out of the Science Institute in Fairfax County, Virginia, istic dips at wavelengths of 1 and 2 microme-
way, said Cheng. “If you’re trying to save the and a member of the DART team, at the Fall ters in both cases. That’s strong evidence that
Earth, that makes a big difference.” Meeting. the two asteroids have similar compositions,
And ejecta there was, in spades—on the The reason is probably the different com- said Thomas.
basis of detailed follow-up observations of the positions and surface features of the two bod- Scientists aren’t yet finished with Didymos
Didymos-Dimorphos system, scientists dis- ies, he said. Tempel 1 is rich in volatiles and and Dimorphos: In 2024, researchers involved
covered that Dimorphos is now traveling fine-grained dust; Dimorphos’s surface, on in the European Space Agency’s Hera mission
around Didymos once every 11 hours and the other hand, is littered with boulders. Sci- plan to launch a spacecraft to the system to
22 minutes. That’s a full 33 minutes shorter entists plan to continue to monitor Dimor- further characterize the asteroids—including
than its original orbital period, a finding that phos’s debris plume through at least this accurately measuring the mass of Dimor-
implies that a substantial amount of ejecta month. phos—and to study the crater created by the
was produced. Imagery from ground- and The DART mission also has enabled scien- DART impact.
space-based telescopes has borne that out: A tists to investigate a fundamental question
plume of debris tens of thousands of kilome- about the Didymos-Dimorphos asteroid sys-
ters long currently stretches out from Dimor- tem: Do the two asteroids have the same By Katherine Kornei (@KatherineKornei),
phos. Researchers estimated that at least a composition? It’s a common assumption Science Writer
SCIENCE NEWS BY AGU // Eos.org 7
NEWS
Glacial Ice Offers Polar Bears a Precarious Climate Refuge
D
iscovered in the fjords of southeastern sheep,” said Laidre. The scientists had to every year. That’s one reason Laidre was so
Greenland, the world’s most gene carry noisemakers, flares, and rifles to protect surprised to find a substantial population of
tically isolated polar bear subpopu themselves from the polar bears they were bears in southeastern Greenland at all: The
lation has an unusual relationship to ice. there to study. sub-Arctic region has more than 250 days
Whereas most polar bears rely on sea ice, the Striking out by helicopter, Laidre and her without sea ice every year.
bears recently found prowling Greenland’s colleagues scouted the fjords to find and
southernmost tip also hunt on glacial “capture” bears using sedative darts so they
mélange—the jumble of floating ice that could safely land and approach the animals
“These bears are kind
spills into fjords when glaciers come apart to collect health data. They’d also fit adult
against the sea. females with tracking collars. When capture
These unusual fjord dwellers might offer a wouldn’t be safe for the researchers or for the of homebodies.”
glimpse of their species’ future in the melt- bears, the team used biopsy darts to collect
ing Arctic, researchers said. Ice is already as small tissue samples for genetic analysis
short-lived in the fjords as it is expected to be instead.
in the High Arctic by the end of the century. In addition to the fieldwork, the team used
And as sea ice grows ever scarcer, polar bears satellite imagery to track the ice conditions in The southeastern Greenland bears survive
will be driven farther back into a shrinking the bears’ habitats. But because fjords are so by hunting from the glacial mélange, which
handful of climate change refugia, such as narrow and small, the normal automated flows into the fjords year-round. The strategy
fjords. tools used to track Arctic sea ice just wouldn’t gives the bears plenty of food to eat but also
A multiyear effort to study the bears and work, Laidre said. The team’s ice scientists seems to restrict their movements.
their environment was described in Science had to analyze daily satellite images of the “These bears are kind of homebodies,” said
(bit.ly/fjord-polar-bears) and presented at fjords by hand. Laidre. “[They] would stay in one or two fjords
AGU’s Fall Meeting 2022 (bit.ly/AGU22-polar for 3–5 years. They’d move, on average, 10 or
-bears). Isolated Homebodies 15 square kilometers. Bears in other parts of
Polar bears need sea ice to hunt but can the Arctic will move 1,000 kilometers…[these
Unexpected Discovery endure between 100 and 180 ice-free days bears] really are just stuck in little pockets.”
The research team wasn’t expecting to find a
new subpopulation of polar bears hunting on
fjord ice, said ecologist Kristin Laidre of the
University of Washington. The team’s project
started in 2011 as a multiyear effort to survey
the broader eastern Greenland population,
which hadn’t been studied closely in more
than a decade.
Southeastern Greenland “definitely wasn’t
thought to be a place that would support a
population of polar bears,” said Laidre. “But
we took one or two trips down there and it
kind of struck me. Coming into the fjords, we
were seeing a high density of bears, and I
didn’t really expect that.”
The region is incredibly remote, and doing
fieldwork there was a yearslong logistical
challenge, Laidre recalled. Helicopter fuel
and supplies were cached years in advance,
and the researchers had to get creative with
campsites if they wanted to avoid a daily
4-hour commute to the fjords.
“We lived in abandoned mining camps.
We lived in abandoned weather stations. We
slept in a sheep farm with a couple hundred
u Read the latest news
at Eos.org
Southeastern Greenland’s polar bears use glacial ice to hunt. Credit: Kristin Laidre
8 Eos // MARCH 2023NEWS
This, as well as their habitat’s remote loca-
tion, might explain the bears’ incredible iso-
Scientists EEAGER-ly Track Beavers
lation—the southeastern Greenland bears are
the most genetically isolated polar bears in
Across the Western United States
the Arctic, said Laidre.
Although other polar bear populations are
genetically isolated, have small ranges, or
hunt from glacial mélange, the southeast-
ern Greenland bears are unique in having all
three of these characteristics, said University
of Alberta ecologist Andrew Derocher, who
was not involved in the study.
Symptom of Climate Change
The discovery of this unique bear population
shows that glaciers that flow into the sea offer
polar bears a refuge from melting sea ice. But
although it might be tempting to see the
southeastern Greenland bears as a new hope
for their species in our warming world, it’s
not that simple.
Lifestyles such as those of the Greenland
bears are “a symptom of climate change,”
said Derocher. “In a warming Arctic, this is a
scenario that we’re going to see played out in A cascade of beaver ponds on South Fork Middle Crow Creek in the Happy Jack Recreation Area in Wyoming
many, many different places where…groups cuts through a landscape of evergreens and other trees. Credit: Emily Fairfax
of bears become more isolated.”
Sea-terminating glaciers such as those in
B
southeastern Greenland aren’t common in
most of the Arctic, which includes northern eavers are among the world’s most entists identify the landscape-scale features
effective engineers. Members of this created by beaver families.
keystone species build dams and canals Through a combination of fieldwork and
and, in so doing, create entire, multilayered remote sensing, Fairfax tracks where beavers
wetland ecosystems. Beginning in the 1600s, reside across the western United States. To
“Polar bears are still at risk however, the fur trade decimated North Amer- make the process more efficient, she’s work-
from climate change.” ican beaver populations. ing with Google Earth Engine to develop the
The species began rebounding in the early Earth Engine Automated Geospatial Element
20th century but sometimes came into conflict Recognition model—aptly called EEAGER—
with the landscape, as by the 1940s and 1950s, which uses machine learning to rapidly iden-
people were aggressively modifying streams tify beaver dams in satellite and aerial imag-
Canada and Russia, where most polar bears to maximize agricultural yield. Returning to ery.
live. And ice conditions in the Arctic can be their former haunts meant persecution as
erratic, said Derocher, adding that one or two beavers flooded crops and felled orchards,
unusually warm winters could “blink out” a explained Alexa Whipple, program director for
small, isolated population such as the one in the Methow Beaver Project (part of the non-
the study. profit Methow Salmon Recovery Foundation). We often want beavers
So rather than being a saving grace for the Now, humans are starting to recognize that to move back in to
bears’ species, said Laidre, southeastern beavers, though still considered pests by
Greenland’s fjords are better understood as a some, benefit landscapes in myriad ways. For landscapes to do the
glimpse of the future—and a potential oppor- instance, beaver activity can reduce erosion, engineering for us.
tunity for scientists to better understand the create habitat for other species, and maintain
specific challenges climate change will bring. wetlands.
“Polar bears are still at risk from climate In fact, we often want beavers to move back
change,” she said. “This small group of bears in to landscapes to do the engineering for us,
is going to teach us a lot about the future of said Emily Fairfax, an assistant professor at In work presented at AGU’s Fall Meeting
the species, but [the way they live] is not California State University Channel Islands. 2022, Fairfax found that E EAGER decreased
going to save polar bears.” “But how are we going to know if they are the time needed to map beaver dams by about
doing that,” she asked, “if we don’t even 80% (bit.ly/AGU22-EEAGER). By rapidly find-
know where they are?” The answer lies in ing beaver ponds and comparing their chang-
By Elise Cutts (@elisecutts), Science Writer remote sensing imagery, which can help sci- ing distribution over time, scientists like
SCIENCE NEWS BY AGU // Eos.org 9NEWS
Fairfax can track beaver populations to quan- activity. With Google Earth Engine, the data resulted in fire-resistant habitats. “In these
tify the effects of their environmental engi- querying and processing happen in the cloud, beaver complexes, everything stays wet,”
neering. Fairfax explained, so she doesn’t need to add said Fairfax, which means that fires cannot
more hard drives to her already impressive easily burn these ponds.
Dams Versus Cul-de-Sacs stash. “I’ve gone to [wildfire] sites where I fully
The amount of existing and incoming imag- Fairfax noted that the model wouldn’t work expected the beavers to be dead,” she recalled,
ery isn’t an impediment for sky-based bea- as well as it does without extensive field map- but “the evening rolls around and the beavers
ver surveillance. Beaver dams remain in place ping of beaver dams (and not beaver dams), come swimming out.”
for 5–7 years on average, said Fairfax; very which involves wading through muck and Channel modifications, such as straight-
high resolution data that are publicly avail- dense vegetation. But although pond-specific ening bends to transport logs and barges,
able come out at least every couple of years beaver studies are important, looking at how result in water being whisked rapidly down-
and sometimes more often when fires and beavers affect entire watersheds can now be stream, said Chris Jordan, a research fisheries
droughts strike (which is becoming more efficiently accomplished in beaver-based biologist with NOAA’s National Marine Fish-
common). Lower-resolution data sets can research. eries Service who was not involved with the
provide helpful imagery about once per week, For regions still needing ground truthing, study. Beavers’ networks of dams, canals, and
filling in any gaps. drones now expedite this process. However, felled trees do the opposite, slowing water
However, tracing beaver dams in such because Fairfax’s research has been focused down, which—like magic, except that it’s
imagery is incredibly time-consuming, often on the western United States, EEAGER may physics—restores river systems, he said.
taking weeks to months. With large quanti- be biased. “We actually don’t know how Given time and opportunity, beavers will
ties of imagery, which Fairfax noted is a good it would do in places like Canada or Min engineer an entire valley floor, which could
pleasant problem to have, the process can nesota,” she said, “because it hasn’t been be more than a kilometer wide, said Fairfax.
become a nightmarish sea of external hard trained there.” That seemingly magical engineering lets
drives holding terabytes of data. water seep into the soil, allowing streams to
Fairfax and her colleagues at Google who Slowing Down Water, Speeding Up reconnect to their floodplains. Simple or
specialize in neural networks, machine learn- Recovery degraded ecosystems can transform into riv-
ing, and artificial intelligence trained the After the results from E EAGER go through erscapes with healthy food chains.
EEAGER model with 8,000 of Fairfax’s man- quality control, calculations can address For example, because endangered salmon
ually identified beaver dams and another whatever the science question at hand may and similar fish species are born and die in
5,000 from other coauthors. Because the be. For instance, in research currently under freshwater, they depend on healthy river
model was convinced that cul-de-sacs were review, Fairfax looked at whether beaver conditions to complete their life cycle, Jordan
also beaver dams, they had to train the model dams became fire refuges during three Rocky said. Growing more fish requires ants, earth-
on “not dams” as well. Mountain megafires in 2020. In some water- worms, and other floodplain-dwelling inver-
EEAGER can now sort through massive sheds, beavers had dammed every single tebrates to become fish fodder. But for that
amounts of satellite and aerial imagery and stream from start to end, she said. These sin- part of the food chain to exist, landscapes
identify pixels that contain evidence of beaver uous stretches of hydrologic connectivity around rivers need to be wet at least some of
the time. Beavers create the necessary wet-
land environments that then become biodi-
versity hot spots.
“In these beaver
complexes, everything
stays wet.”
Acquiring regular snapshots of beaver
ponds from space, combined with algorithms
doing the tedious work of examining millions
of kilometers of streams, means new ways to
quantify the impact beavers are having on the
landscape, Jordan said.
Beaver dams create a wet refuge from wildfires. Little Last Chance Creek in California burned during the 2021 By Alka Tripathy-Lang (@DrAlkaTrip), Science
Beckwourth Complex Fire. This photo was taken 1 year later. Credit: Emily Fairfax Writer
10 Eos // MARCH 2023NEWS
Drones Make Weather Prediction at the Poles Easier
I
n February 2022, a drone flew off the deck anemometer measurements and calculate
of the Japanese vessel Soya and over the the wind speed in the surrounding environ-
ice-covered Sea of Okhotsk in the north- ment.
western Pacific Ocean. The only difference Once the calibrations on the drone were
between this uncrewed aerial vehicle (UAV) accurate, the researchers headed to the Sea of
and one you could buy at any electronics store Okhotsk, collecting 18 wind speed measure-
was an extra sensor that researchers had ments over water. By comparing the drone
added to measure wind speed. data with the wind sensors on the ship, they
The flight was a test to see whether collect- determined that the drone was able to make
ing wind speed measurements in remote accurate measurements of wind speed in the
regions could be made more accessible and field.
less expensive. The researchers recently pub- Adding an inexpensive, lightweight sensor to a
lished their findings in Drones (bit.ly/weather commercial drone allowed researchers to accu- Finding What Flies
-drones). rately measure wind speeds in the Arctic. Credit: Antonio Segalés Espinosa, a researcher at the
Jim Makos, CC BY-ND 2.0 (bit.ly/ccbynd2-0) Cooperative Institute for Severe and High-
Impact Weather Research and Operations at
the University of Oklahoma who designs
Drones are “reusable, Drones have many advantages, said Brian
w eather-measuring drones but wasn’t
involved in the current work, said that in his
they’re cheap, they’re Greene, a postdoctoral fellow at the Univer- research he’s avoided using thermal ane-
portable…they’re able
sity of Oklahoma who has used drones in the mometers because they are a bulky add-
Arctic but wasn’t involved in the new study. on. “Adding more extensions to the drone
to reach areas of the “They’re reusable, they’re cheap, they’re doesn’t really help to get the drone within the
portable,” he said, and “they’re able to reach performance we want for severe weather,” he
atmosphere that we don’t areas of the atmosphere that we don’t typi- said. Inoue agreed, noting that a limitation of
typically have access to.” cally have access to with our normal, everyday their design is that they’re confined to flying
sampling techniques.” the drone in clear weather.
A Cost-Effective Option
Scientists have used custom, purpose-built
“Although meteorological UAVs can [per- drones to make observations of weather and
form] wind profiling, they are usually expen- sea ice levels at the poles before, but these Including a thermal
sive to buy or operate by a third party,” wrote units are not commercially available. In the
anemometer on a
Jun Inoue, a researcher at the National Insti- new study, the researchers used the common
tute of Polar Research in Japan and lead author DJI Mavic 2 drone and attached a thermal commercially available
of the study, in an email from a research ves-
sel in Antarctica. Lightweight and inexpensive
anemometer, which measures changes in
temperature due to airflow and translates
drone has benefits.
anemometers—devices that measure wind them to wind speed. Although scientists typ-
speed and direction—attached to a smaller ically use a different sensor for this purpose—
UAV can make the same measurements, he an ultrasonic anemometer—the thermal
wrote. Inoue and his colleagues are designing variety is lighter and less expensive. Including a thermal anemometer on a
a unit that fits the bill. The researchers wanted to collect wind commercially available drone has benefits.
speed data while the drone was ascending The design could be a way for people who
Where Drones and Meteorology Meet and descending; stopping for each measure- don’t have the time and money to build their
Wind speed measurements throughout the ment is a drain on battery life. However, the own specialized drone to collect data, Greene
lowest layer of the atmosphere, called the movement of both the drone and its propel- said.
boundary layer, help to inform weather pre- lers would create extra airflow over the sen- Inoue said he aims to improve the deliv-
dictions and climate models. But weather sor. For the wind speed measurements to be ery of data from the drone to researchers.
stations are difficult and costly to maintain accurate, the researchers had to compensate “We will use this system over the Southern
in many places around the world, particularly for this disturbance. In a laboratory, they Ocean and Antarctica to study the atmo-
at the poles. “Cost-effective, frequent data visualized airflow over the drone with smoke spheric boundary layer structure,” he wrote.
acquisition at many stations is the chal- and lasers. Using videos that looked as if they “The next step is near-real-time data trans-
lenge,” Inoue wrote. Weather stations are could have been taken at a dance club, the fer for numerical weather predictions.”
also limited to collecting data at a single loca- researchers were able to track smoke particles
tion. To overcome these issues, scientists and translate that information into a velocity
have turned to drones to get weather data in of airflow over the drone. They could then use By Andrew Chapman (@andrew7chapman),
hard-to-reach locations. these measurements to correct the thermal Science Writer
SCIENCE NEWS BY AGU // Eos.org 11NEWS
New Crowdsourced Science Project Will Study Sprites
S
prites, elves, trolls, and pixies. “Their photos are fantastic,” said Kosar, Aside from collecting and collating images,
No, we’re not talking about fairy- but “other than a few researchers, the science a key aim of the Spritacular project is to sup-
tale creatures. These curiously named community is largely unaware of their efforts port new observers with workshops and edu-
phenomena are all types of transient lumi- and observations.” cational resources. In addition, Kosar is look-
nous events (TLEs)—bursts of red and blue Kosar, who was previously involved in an ing to explore the role of atmospheric gravity
light that occur high above thunderclouds and aurora-spotting crowdsourced science proj- waves in sprite formation. Amateur scientists
last for as little as a fraction of a second. ect, saw an opportunity to create a commu- frequently capture sprites and gravity waves
Eyewitness reports of strange flashes nity in which weather photographers and concurrently, but more observations are
above thunderstorms were reported for more scientists could collaborate. The data and needed to support the idea that these ripples
than a century before scientists accidentally images collected by Spritacular will be used in the atmosphere may help seed sprite for-
caught one on film during a test for a rocket by scientists for new and ongoing research mation.
mission in 1989. Since then, scientific cam- into TLEs.
paigns have captured stills and high-speed
recordings of sprites and other TLEs around Knowing Where to Look
the world.
Scientists have many unanswered ques-
Kosar recently had her first sprite-chasing
experience with weather photographer Paul
“More eyes on the skies
tions about the phenomena, said Burcu Kosar, Smith in Oklahoma. “We were out night will give us unbiased
a space physicist at NASA’s Goddard Space
Flight Center. Kosar is leading Spritacular, a
after night scouring the skies,” she said.
The biggest challenge of sprite chasing is
coverage across the
community effort to build the first global being in the right place at the right time, said globe.”
database of sprites and other TLEs for scien- Smith, who has been photographing the
tific study. phenomenon for 6 years. Not every storm is
“We need more observations to under- going to make a sprite: “It takes experience
stand various aspects of sprites and other in reading how storms evolve and the types
transient luminous events,” said Kosar. “We of lightning responsible.” Working Together
may even find new types.” “You don’t need specialized equipment to “More eyes on the skies will give us unbiased
capture a sprite, though,” said Smith, just a coverage across the globe,” said Caitano da
Spectacular Sprites standard digital single-lens reflex camera Silva, an assistant professor of physics at the
Characteristic examples of sprites include and some practice. New Mexico Institute of Mining and Technol-
carrots, which look like bunches pulled right
out of the garden, and jellyfish with dangling
tendrils.
“It’s an electrical zoo
up there.”
Sprites are generally hidden from view,
occurring at an altitude of roughly 80 kilo
meters. “Electrical activity affects the atmo-
sphere above [a storm], creating various opti-
cal phenomena—it’s an electrical zoo up
there,” said Kosar, who introduced Spritacu-
lar at AGU’s Fall Meeting 2022 (bit.ly/AGU22
-Spritacular).
Whereas scientific efforts to document
sprites have declined recently, Kosar said,
amateur sky watchers known as “sprite chas-
ers” have been sharing photos of them online
for years. The largest group of sprite chasers,
the International Observers of U pper-
Atmospheric Electric Phenomena, started in Large thunderstorms are capable of producing lightning and other kinds of electrical phenomena called transient
2013 and now has more than 7,000 members. luminous events (TLEs). The most common TLEs include red sprites, blue jets, and elves. Credit: NOAA
12 Eos // MARCH 2023NEWS
Stories Scribed on Palm Leaves Help
Scientists Understand Ancient Eruption
F
ire rained from the sky. Avalanches During the past 10,000 years, large eruptions
coursed down a collapsing mountain. have punctuated Rinjani’s history, with the
An island kingdom perished. These 1257 event ranking among the most explosive
apocalyptic scenes describe the 1257 eruption in recent times, said Vidal, who has worked
of Samalas—the most explosive volcano on Samalas but was not involved in this study.
you’ve never heard of—if historic records
from the Indonesian island of Lombok are
true.
In a new study, Panthéon-Sorbonne Uni-
versity doctoral student and geomorpholo- Like avalanches, these
gist Mukhamad Malawani and his colleagues flows “destroy[ed]
used locally preserved historic records called
babad to reconstruct what Lombok may have everything in their way.”
been like before, during, and after the Sama
las eruption (bit .ly/palm -leaf -eruption).
Investigating the changes wrought by this
catastrophe may help scientists understand After the eruption, the island morphed
ancient evacuation processes, posteruption from a lush paradise into a dry, ash-covered
recovery, and societal resilience. landscape, according to study coauthor
Franck Lavigne, a geographer at Panthéon-
Paradise Lost Sorbonne University who has worked on the
Lombok is nestled between the islands of Bali Samalas eruption for the past decade.
to the west and Sumbawa to the east. These Prior studies of the meters- to tens-of-
islands form part of the v olcano-studded meters-thick deposits expelled from the vol-
A red jellyfish sprite was captured by veteran sprite Indonesian arc, largely the product of sub- cano helped scientists such as Vidal recon-
chaser Paul Smith over Oklahoma in June 2022. duction as the Australian tectonic plate’s struct the eruption itself. Ash, pumice, and
Credit: Paul Smith/@paulmsmithphotography northwestern oceanic edge dives below the gas rose into the atmosphere as the eruption
Sunda plate. The Rinjani volcanic complex, began. The cloud spread horizontally, raining
crowned by a l ake-filled caldera left by the ash and pumice onto, and even beyond, the
Samalas eruption, reigns over Lombok’s island. Once the gas sustaining the plume was
ogy who is not involved in the Spritacular landscape, according to Céline Vidal, a volca- exhausted, the towering column collapsed,
project. “Working together significantly nologist at the University of Cambridge. forming clouds of hot gas, ash, and other
increases our chances of new discoveries.”
Da Silva also hopes the new project will
lead to better classification of sprites and
other TLEs. Classification so far has drawn on
data collected by a small number of research
groups.
For amateur scientists like Smith, Spritac-
ular is a “fantastic opportunity to join forces
with scientists—if we can analyze each of our
shots, just imagine what we might find out.”
For Kosar, the project isn’t just about fur-
thering science. “The study of TLEs, in a way,
started with citizen scientists, and we want to
work with them,” she said, adding that there
are many ways for people to get involved
beyond making observations. “It’s about cre-
ating a community. You don’t have to be an
observer—you’re welcome on board even if
you just want to learn more.”
By Erin Martin-Jones (@Erin_M_J), Science The palm leaf pages of Babad Lombok, written in Old Javanese, may provide clues about a little-known 1257 vol-
Writer canic eruption in what is now Indonesia. Credit: Franck Lavigne
SCIENCE NEWS BY AGU // Eos.org 13NEWS
found, Lavigne said he hopes that houses or
temples might be unearthed in the future.
To extract what happened to the island’s
inhabitants after the eruption, Malawani,
Lavigne, and colleagues traced the paths of
refugees by matching place-names listed in
the babad with modern geography, as well as
with names taken from c olonial-era maps.
However, these paths could be describing
either immediate evacuation or later migra-
tion, said Lavigne. “It’s not always clear.”
Babad Lombok also records which leaders
built new settlements. For example, import-
ant people of Pamatan, such as the governor,
A cliff of pumice about 35 meters high, left from the 1257 volcanic eruption, looms above a local beach on the harbormaster, headman, and royal family,
island of Lombok. Credit: Franck Lavigne each oversaw construction of a new village.
On Lombok, resilience meant resettlement
away from the pumice-coated plains, said
Lavigne.
debris produced by the eruption that flowed Javanese word for pumice, which helped to
along the ground, rapidly traversing the land- confirm the link between the babads’ descrip- Timelines
scape. tions and the Samalas eruption. “We know For the past few decades, knowledge of vol-
Like avalanches, these flows “destroy[ed] that it’s this eruption because it’s the only canic eruptions in general has come from
everything in their way,” Vidal said. Soon [recent] eruption that produced pumice,” detailed studies of volcanic deposits and
after, mudflows called lahars, caused when said Lavigne. “What we see in the field cor- monitoring of those sites, said Agung Hari-
rain follows such an eruption, capped the vol- responds to the descriptions in the babad.” joko, a volcanologist at Gadjah Mada Univer-
canic deposits, she said. In that context, Babad Lombok and Babad sity in Yogyakarta, Indonesia, who was not
Sembalun describe the collapse of Mount Rin- involved with this study. Historical records,
Babad jani, along with debris flows and avalanches. such as those described in the new study, may
Babad are written collections of oral traditions Babad Suwung, which includes the story of a provide additional information about past
often transcribed in an Old Javanese script group that journeyed to the nearby island of eruptions and mitigation efforts that’s oth-
that few people can read. The sacred texts Sumbawa just before the eruption, describes erwise hard to find.
contain a mixture of legend and fact, said “fire-rain” and burning winds—likely a surge In particular, said Vidal, little-studied oral
Lavigne. This is partly because oral traditions of hot gas and ash—that seared the village histories, common in Indigenous cultures,
change as cultures do. across the strait. contain invaluable information. “This study
The researchers focused on three babad was remarkable,” she said, because it uses
likely compiled in the 18th or 19th century— local records, initially transmitted orally,
several centuries after the Samalas eruption. after much of Lombok was destroyed.
Babad Lombok had already been translated However, because the babad do not include
into modern Javanese and Indonesian and Resilience meant dates, reconstructing timelines is tricky.
resides at the Museum of Nusa Tenggara
Barat. Babad Suwung, also property of the
resettlement away from “Impacts immediately after an event are dif-
ferent from the long-term impacts, and peo-
museum, had yet to be translated from Old the pumice-coated plains. ple’s understanding of that impact changes
Javanese, so Lavigne and colleagues arranged with time,” said volcanologist Amanda Clarke,
for a translation to occur in a village where the a professor at Arizona State University who
person reading the babad sang from the palm was not involved with the study.
leaves in a ceremony attended by all the resi- For instance, how long the recovery took
dents. The third, Babad Sembalun, is familiar Before and After is not mentioned in any documents from
only to people who live in the Sembalun Valley Babad Lombok mentions Pamat an, a lost Lombok, said Malawani, who is also a lec-
on the northeastern flank of Samalas, where kingdom in a lowland, coastal area, said turer at Gadjah Mada University. Fortunately,
the original palm leaves remain. L avigne. With a bustling population of another document from Java, the Desavar- ´
With the translations, Malawani, Lavigne, 10,000, the fabled city boasted infrastructure, nana,
. helped the researchers bracket the
and their colleagues examined the three agriculture, fishing, and commerce but was recovery efforts to about a century.
babad for any information pertaining to an wiped out by an eruption, according to the Many babad still need to be translated and
eruption. Because the babad provide no abso- text. If Pamatan exists below Samalas’s vol- studied, said Lavigne. “Some of them still
lute time constraints for the Samalas erup- canic deposits, nobody knows where it lies, may have some interesting information.”
tion, the researchers had to verify that these he said, though they have some educated
records truly describe the event. To do so, guesses. Pumice quarries dot the island,
they relied on comparisons. For instance, trenched in deposits that can be as thick as By Alka Tripathy-Lang (@DrAlkaTrip), Science
Babad Lombok specifically mentions the Old 50 meters. Though no settlement has been Writer
14 Eos // MARCH 2023NEWS
Were Impressionist Masters Painting a Polluted Reality?
I
mpressionist painters of the 19th century
were famous for capturing the vitality of a
scene and the fleeting nature of light,
rather than meticulously reproducing every
detail in a composition. But a new study pre-
sented at AGU’s Fall Meeting 2022 suggested
that trends toward hazier contours and whiter
palettes found in works by J. M. W. Turner and
Claude Monet may, in fact, be accurate rep-
resentations of optical effects associated with
air pollution.
The Impressionists (influenced by Turner
and exemplified by Monet) were interested in
contemporary scientific advances, and they
often painted outdoors to capture the world
in its true light. But their color palettes and
painting techniques—visible brushstrokes
with minimal representations of form—have
been attributed largely to stylistic choice. The
new research, led by Anna Lea Albright at
the Laboratory of Dynamic Meteorology at
Sorbonne University and École normale
supérieure, suggested that Impressionists
may have been more faithful to meteorolog-
ical reality than previously assumed.
The study focused on Turner and Monet,
iconic artists who frequently painted serialized
cityscapes in London and Paris, urban areas
that experienced increasing air pollution
during the Industrial Revolution (b it. ly/ Claude Monet was fascinated by the smog of turn-of-the-century London, an atmosphere reflected in his 1904
Impressionism-p ollution). “We don’t want to painting of the Houses of Parliament. Credit: Musée d’Orsay
say these artists were just instruments pas-
sively recording their environment—that
would diminish their obvious creative genius.
The key idea is that change to the environment analysis to assess the clarity and color pal- same model found similar trends in paint-
provided new creative impulses, new ways of ettes in Turner’s and Monet’s paintings. The ings of London and Paris by other artists,
seeing,” said Albright, who did the research researchers’ technique began by taking a including Camille Pissarro, James McNeill
with Peter Huybers, a professor of Earth and high-resolution photo of a painting and con- Whistler, and Gustave Caillebotte.
planetary sciences at Harvard University. verting it into a matrix—essentially a set of “Turner was born in the Age of Sail, and he
numbers corresponding to different colors. died in the age of coal and steam,” said
London Becomes “the Big Smoke” They then used mathematical wavelet anal- Albright, who believes that industrialization
Albright and Huybers first estimated air pol- ysis to determine how sharp the edges are influenced not only what Turner painted but
lution levels during the periods when Turner between colors at different scales. Color also how he painted it. She said this influ-
and Monet were most active. Given that rou- models helped determine the images’ “haz- ence is perhaps best illustrated in Rain,
tine air quality monitoring began only in the iness.” Steam, and Speed (1844), a frenetic scene fea-
mid-20th century, the researchers used fuel The researchers assessed 60 oil paintings turing a train crossing a bridge in a golden
inventories as a proxy. by Turner spanning the years 1796–1850 and landscape, with a hare darting along the
In Britain, the Industrial Revolution was 38 paintings by Monet dating from 1864 to track.
gathering steam by the 1830s. Sulfur dioxide 1901, after first calibrating the technique
(SO2 ) produced by burning coal was polluting using photos of present-day cities in both Monet, the Smog Seeker
the air, particularly in London, where concen- clear and polluted conditions. Monet’s early paintings were traditionally
trations increased throughout the 19th cen- As pollution levels rose, the styles of both figurative. His style became increasingly
tury. In Paris, SO2 levels climbed only in the artists evolved from more clearly demar- Impressionistic as the locations in which he
latter half of the 19th century, and peak levels cated shapes toward blurrier edges and was painting became increasingly polluted.
were never as bad as those in London. whiter color palettes. The trend was consis- Albright said Monet’s work, completed
Pollution is known to affect visibility at tent even after the researchers accounted for generations after Turner, may actually rep-
street level, so Albright’s group used image factors such as subject and time of day. The resent an amplified version of real pollution
SCIENCE NEWS BY AGU // Eos.org 15You can also read
