Warming Trends: Google Earth Shows Climate Change in Action, a History of the World Through Bat Guano and Bike Riding With Monarchs

A column highlighting climate-related studies, innovations, books, cultural events and other developments from the global warming frontier.

Earth from space. Credit: Heritage Space/Heritage Images/Getty Images

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Watching Climate Change at Work

An updated Google Earth feature shows climate change in action over the last four decades.

Launched in collaboration with U.S. and European government agencies, Google Earth Timelapse contains 37 years worth of changes to Earth’s surface, many related to the climate crisis. 

In the Amazon, for example, the tool shows large swaths of forest traded for cattle ranches and soybean farms. In Greenland and Antarctica, users can see miles-long glaciers quickly melting away. Wildfire smoke fills the skies above Alberta, Canada; the coast of the Bahamas is devastated by a hurricane; and the Aral Sea in Kazakhstan loses 90 percent of its surface area in a matter of decades.

The tool also shows how landscapes have changed as humans have demanded more energy. The user can witness fracking well pads popping up on the North Dakota landscape and mountaintop mining turning West Virginia forests from green to brown. 

But the timelapses also show society’s transition to cleaner energy, with millions of solar panels appearing across rural China and outside of Abu Dhabi, and strings of wind turbines dotting California’s landscape and Jordan’s mountaintops.


A 10,000-Mile Ride With Monarchs

When Sara Dykman was looking for her next big adventure, she came across the monarch butterfly migration route. Beginning in El Rosario, Mexico, moving north through the central U.S., up through Ontario and then back south to El Rosario in nine months, “the monarch flies about the same distance a cyclist can go,” she thought.

So Dykman, then 32, decided to ride alongside the monarchs during their 2017 migration. She had done four long-haul bike rides before, so she planned a 10,000-mile ride through three countries, stopping to give presentations and spread the word about the declining monarch population along the way. She loaded up her rickety bicycle with 70 pounds of gear and took a bus to Mexico.

“I thought it was going to be just another bicycle tour, but it turned out to be much more,” Dykman said. “This network of people taking care of the monarchs, these monarch stewards, they adopted me just as they adopt the monarchs.”

Monarch butterflies take a multigenerational migration each year between Mexico, the U.S. and Canada. Credit: Tarnya Hall

Dykman has written a book, published this week, about her 264-day journey, during which she stayed with 68 families, encountered 722 monarch butterflies and 245 monarch caterpillars and told her story to more than 9,000 people.

The monarch butterflies that make this migration are threatened largely by habitat loss that has caused their population to plummet by about 80 percent. Dykman told people along the route that they could help by planting native plants to provide nectar for monarch butterflies, especially milkweed, which is the only plant that monarch caterpillars can feed on.

“If someone in New York finds a monarch in their yard, there’s a good chance that it’s because someone in Kansas had a garden,” Dykman said. “And the reason that monarch in Kansas survived was because someone in Texas had a garden. So all of our actions are connected.”


The History of Bat Guano

A pile of bat poop two meters deep contains 4,300 years of recently discovered history. The rare preserve in a Jamaican cave contains chemical clues showing when the island’s native flora were traded for sugarcane, when drivers around the planet switched from leaded to unleaded gasoline, when governments began testing nuclear bombs and when synthetic nitrogen fertilizers became farmers’ fertilizer of choice. 

Researchers detailed their discovery in a recent study published in the Journal of Geophysical Research: Biogeosciences. Bat feces—known as “guano”—were a valuable resource used as agricultural fertilizer and in gunpowder, so existing preserves are rare, study author and University of Ottawa lake sediment scientist Jules Blais said. 

“A steep vertical drop in the cave made it very inaccessible, which probably saved it from being removed centuries ago,” Blais said.

A key finding from the analysis of bat guano was how the flying mammals’ diet had changed through time. When the climate was colder and wetter, bats tended to eat more insects, while during warmer, drier periods, bats favored fruit.

Understanding how bats adjusted to climate changes helps researchers understand how bats might be affected in the future by global warming. Jamaica is expected to become warmer and drier with climate change, so bats need more fruit to be available in their habitat. 

“Their survival is contingent on their habitats being maintained,” Blais said.


A Documentary Looks at Whales in Depth

While free-diving off the coast of New Zealand, National Geographic documentary filmmaker Brian Skerry was shooting footage of orca whales when a female orca swam toward him with a stingray in her mouth. She dropped the dead fish on the ocean floor in front of him and swam away.

“Then she comes back and faces me, this giant orca, a couple of feet away from me with this dead stingray laying on the bottom in between us,” Skerry said, “and she’s looking at me and looking at the ray as if to say, ‘Are you gonna eat that?’”

This was one of many moments of humanlike interaction Skerry witnessed while shooting “Secrets of the Whales,” a new, four-part documentary series from National Geographic, premiering on Disney+ on Earth Day, April 22. Skerry also authored a book of the same name, which is available now.

Each episode of the documentary series highlights a whale species like orcas or belugas, and dives into their rich cultures and deep familial bonds, with societal intricacies that scientists are just beginning to understand. 

The documentary shows that sperm whales belong to families with distinct dialects, and that whales from different families don’t intermingle. It also shows a beluga whale pod caring for a young narwhal, documenting the first known cross-species adoption.

Though the film does not overtly address the conservation or climate change issues that whales are facing, Skerry hopes the film will still lead viewers to consider their impact on the planet and what is at stake.

“Viewers can see the ocean and our planet through the lens of culture with these animals and these families exhibiting emotions, passing on these ancestral traditions and all this richness of their society,” he said. “Once you know that, you can’t unknow it.”

After witnessing the depth of whale culture and connection between whales, Skerry said he walked away with a bigger appreciation for his own relationships.

“In the last year, being locked down in the pandemic with my family, thinking about how much time I spent away doing this work, I realized that the whales sort of reminded me of things I already know,” he said. “Even though life in the ocean is difficult for these animals, they make time for each other on a daily basis or every few days, they come together, they socialize, they reaffirm those community bonds.”



A massive brood of cicadas is poised to emerge any day now in the eastern United States, and cicada researchers are gearing up to study the phenomenon that comes once every 17 years.

Brood X, which last emerged in 2004, is one of the biggest groups of periodical cicadas. Trillions of bugs known for their loud clicking and buzzing will quickly hatch, mate and die this spring, from Washington, D.C. to Illinois, and from Michigan to Georgia.

John Cooley, a cicada researcher with the University of Connecticut, studied the 2004 emergence and plans to create a detailed map of the 2021 emergence. Though he doesn’t expect much to have changed, he said, this data could be important for future climate research.

“We need to get data on how periodical cicadas respond to climate change, especially that caused by human activities,” Cooley said. “You won’t be able to answer that in a field season worth of study, but we can gather baseline data that will help people in the future understand these things.”

Climate change could disrupt the timing of cicada emergences, Cooley said. If spring comes earlier, more cicadas could emerge years before they are supposed to, potentially leading to a breakdown in the cicadas’ periodical cycles.

But the cicada is a relatively old insect, with lineages dating back 5 million years, Cooley said. They have survived climate change in the past—their current range was under glaciers 10,000 years ago.

“They’ve responded to that kind of climate change, there’s no doubt that they can,” Cooley said. “So the question is, what happens when the climate changes quite fast?”