Acutely aware of how global warming is damaging the planet, coral reef scientist Kim Cobb has responded to recent political developments and changes in climate policy by trying to cut her own carbon footprint.
Image: picture-alliance/dpa/P. Mumby
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For Kim Cobb, a researcher at Georgia Tech University in the United States, 2017 was a year of climate action, as she took concrete steps to reduce her greenhouse gas footprint. Like many other climate scientists, she says we must practise what we preach.
"I got the news at a research site in the remote Pacific Ocean where we were studying a reef that had just been killed by global warming. It was a shock, and I think had a much deeper resonance of despair and doom for those of us working in the climate science and policy world. For me personally it was the start of a profound two-month depression," she said.
Kim Cobb: "We have to talk about climate protection solutions. It's not enough to just complain."Image: Mark Keever
Trump has repeatedly dismissed climate change as a hoax. For Cobb, his election made all her efforts seem "insufficient."
"When I returned from the research expedition it seemed that most of America had moved on, but I had trouble getting out of bed for two months. I was grasping at straws for ways forward," she said.
The turning point came on New Year's Day 2017, which also marks the birthday of her twin daughters. The process of re-engaging with her family, peers and community was, she said, shaped by the need to do more about global warming on a personal and professional level.
"It became clear that national policy would not, at least in the near term, fill the void left by inaction on personal carbon footprints," she said.
Since the start of 2017, Cobb said she and her kids have walked, rather than drive, the mile (1.6 kilometers) to and from school, and she cycles the 3 miles to and from work. Her husband also leaves the car behind, at least half the time.
And the scientist hasn't stopped at greener travel.
Cobb said she also offset the carbon output of all her air travel at a cost of several thousand dollars by donating to Trees Atlanta, a non-profit that conserves and expands the US city's urban forest. Starting in January 2018, her family became mostly vegetarian, shaving several tons from their household CO2 emissions.
Cobb said there are effective, indirect ways to nudge society toward the collective greenhouse gas cuts needed to avoid catastrophic global warming.
"As a climate scientist who can see into the future, are you doing what you can to inspire your friends, family, and members of the general public to shrink their footprints?" she asked.
"We need to talk about solutions to climate change, rather than continue to scream and yell about the problem. People need to see a way forward, and to feel like their actions matter," Cobb said.
"They need inspiration, leadership, and a sense of collective action. And scientists can play a key role in building that momentum."
Too hot for turtle guys: Great Barrier Reef is dangerously warm for male green sea turtles
Because of warming climates, green sea turtles at the Great Barrier Reef are having female babies almost exclusively. This could lead to the end of the entire species.
Image: Imago/Imagebroker/N. Probst
Single green females only?
In the largest green sea turtle colony, a lopsided majority of newborn babies are female. Male turtles hatch from just one percent of the eggs around the Great Barrier Reef. Researchers now fear for the survival of the species.
Image: picture alliance/dpa/Prisma/R. Mohammed
Too hot for guys
When sea turtles first lay their eggs, it's not initially clear whether male or female young ones will hatch. That's determined by the temperature of their surroundings. The hotter the sand, the higher the probability that babies will be female. From 29.9 degrees Celsius upward, there won't be little turtle boys. And because of global warming, this benchmark is exceeded more and more frequently.
Image: Imago/Nature Picture Library/Zankl
Male or female? Hard to tell
It's difficult to determine a sea turtle's sex. You can only tell for sure once the animal is fully grown - and that takes at least 20 years. That is probably why the surplus of females has gone unnoticed for so long. One way to tell the sexes apart: Male turtles have a longer tail and longer claws.
Image: Imago/imagebroker
Worrying numbers
Now, researchers from the US and Australia have developed a method to determine the sex of green sea turtles via DNA and blood tests while the animals are still young. What they didn't expect is that today already, 90 percent of green sea turtles at the Great Barrier Reef are female.
Image: Getty Images/M. Kolben
Sex is a rare treat
The small number of males is not the only challenge for green sea turtles. They are only sexually mature at 15, and even then, they only have sex every three years on average. Evolutionary speaking, a small female surplus in populations is nothing out of the ordinary. But the turtles cannot survive entirely without men.
Image: Imago/StockTrek Images
200 turtle babies in one nest
Female sea turtles return to the beach where they hatched to lay their own eggs again and again. On Raine Island's beach, the largest nesting ground for green sea turtles in the Pacific, you can find up to 18,000 animals during high season. After the eggs have been warmed by sun and sand long enough, the babies hatch, make their way into the sea and only return once it's their time to lay eggs.
Image: Imago/Zuma Press
Female surplus across the world?
Researchers believe there's a lack of male sea turtles across the world. That's why they're examining the effect that rising temperatures have had on green sea turtle populations along the coasts of Hawaii and on the island of Saipan in the western Pacific. The early gender detection method could lead to surprising results there as well.
Image: Imago/ZUMA Press
Dangerous heat
The results of the Australian study are bad news for other animals as well. Other reptiles, like crocodiles or lizards, also develop their sex due to temperature. With alligators, things work in exactly the opposite way as they do with sea turtles: If it gets too hot, only male babies hatch from their eggs.
