New research from Dartmouth College provides the first evidence that the Arctic's frozen soil is the dominant force shaping Earth's northernmost rivers. Permafrost, the thick layer of soil that stays frozen for two or more years at a time, is the reason that Arctic rivers are uniformly confined to smaller areas and shallower valleys than rivers to the south, according to a study in the Proceedings of the National Academy of Sciences.

But permafrost also is an increasingly fragile reservoir of vast amounts of carbon. As climate change weakens Artic permafrost, the researchers calculate that every 1.8 degrees Fahrenheit (1 degree Celsius) of global warming could release as much carbon as 35 million cars emit in a year as polar waterways expand and churn up the thawing soil.

"The whole surface of the Earth is in a tug of a war between processes such as hillslopes that smooth the landscape and forces like rivers that carve them up," said first author Joanmarie Del Vecchio, who led the study as a Neukom Postdoctoral Fellow at Dartmouth with her advisers and study co-authors Marisa Palucis, an assistant professor of earth sciences, and engineering professor Colin Meyer.

"We understand the physics on a fundamental level, but when things start freezing and thawing, it's hard to predict which side is going to win," Del Vecchio said. "If hillslopes win, they're going to bury all that carbon trapped in the soil. But if things get warm and suddenly river channels start to win, we're going to see a large amount of carbon get released into the atmosphere. That will likely create this warming feedback loop that leads to the release of more greenhouse gases."

A six-year-old project to return giant tortoises to the wild in Madagascar could result in thousands of the 350kg megaherbivores re-populating the island for the first time in 600 years. The first group of Aldabra giant tortoises (Aldabrachelys gigantea) were brought in from the Seychelles in 2018, and have been reproducing on their own since. Ecologist Grant Joseph explains how reintroducing this tortoise to areas degraded by cattle grazing will help restore the island’s forests, grassy woodlands and shrublands of the past. It could also help prevent devastating forest fires in future.

The Aldabra giant is the second-largest species of land tortoise in the world, after the Galapagos giant tortoise (Chelonoidis nigra). It can live for 100 years and has a fascinating history.

This tortoise evolved from ancestors of Aldabrachelys abrupta, one of two giant tortoises that inhabited Madagascar for 15 million years. Four million years ago, the Aldabrachelys abrupta lineage migrated, likely via a combination of drifting with floating vegetation and assisted by their natural buoyancy and good swimming abilities, to the Seychelles.

From there it moved on to Aldabra (an island 1,000km south-west of the Seychelles), evolving into a third species, the Aldabra giant of today (Aldabrachelys gigantea). Six hundred years ago, all giant tortoises were wiped out on Madagascar by hunters. The reintroduction of the Aldabra giant is the first time giant tortoises have been released in Madagascar since the 1500s.

It all starts with the whistling-thorn acacia trees in the plains of Laikipia, Kenya. These thorny trees had developed a mutually beneficial relationship with the local acacia ant: The trees provide shelter and food for the ants and in return they use their stinging bite to discourage hungry elephants from devouring the trees.

But the big-headed ant changed all that.

Thought to have originated on an island in the Indian Ocean and brought to the area by the movement of people and goods, these invasive marauders arrived around two decades ago and started killing the acacia ants, leaving the whistling-thorn trees vulnerable to herbivores. Diminished tree cover poses a problem for lions because they rely on the element of surprise to ambush their prey, notably zebras.

Earth may have already passed 1.5 degrees Celsius of warming and could be soon heading for 2 degrees of warming, researchers have found after studying sea sponges in the Caribbean.

The study of 300 years of ocean temperature records kept preserved within sea sponges in the Caribbean indicate that global mean surface temperatures may have already exceeded 1.5 degrees Celsius and that a 2-degree Celsius rise could be possible by the end of the decade, according to a paper published in Nature Climate Change on Monday.

Samples of sclerosponge skeletons found in the eastern Caribbean, where the natural variability of temperatures is less than at other locations, indicate that the pre-industrial period can be defined by stable temperatures from 1700 to 1790 and from 1840 to 1860, with the gap defined by cooling related to volcanic activity, according to the study. The sea sponges revealed that warming related to human activity commenced from the mid-1860s, with clear emergence by the mid-1870s, about 80 years before the period indicated by instrumental sea surface records.

BRENDA, Arizona — A clean energy company wants federal permission to use Arizona's sunshine and water to create carbon-free hydrogen fuel in one of the state’s more stressed rural groundwater basins.

Heliogen, a Southern California-based company, last year won the exclusive right to lease more than 3,300 acres of desert east of this small community in western Arizona’s La Paz County for solar energy development. The U.S. Bureau of Land Management had offered the land as one of three designated solar zones in the state, this one just north of Interstate 10 and about 100 miles west of Phoenix

Data from wells that the Arizona Department of Water Resources monitors show all areas of the basin in decline over the last 20 years, and many by dozens of feet. For instance, at the routinely checked well nearest to the proposed solar hydrogen field, depth to water has increased by more than 20 feet since 2003, with each year’s reading adding a point along a relatively straight line downward on the well’s depth chart.

Near the basin’s most intensive farm pumping farther east, Department of Water Resources chief hydrologist Ryan Mitchell said, land has subsided 25 centimeters, or nearly 10 inches, since 2010.

As previously reported by Hydrogen Insight, Europe’s largest hydrogen car market, Germany, saw an almost 70% reduction in new FCEV registrations in 2023.

However, the data from France shows that the country is becoming one of the most dynamic FCEV markets in Europe — although hydrogen vehicle sales are still tiny compared to those of battery-electric equivalents — with the UK and Czechia the only other European nations to have seen more than ten FCEV registrations per HRS last year.

In Switzerland, which has one of the largest concentrations of HRSs in Europe, total new registrations for FCEVs fell by 50%, with just 28 passenger cars and ten commercial vehicles registered last year, the Swiss Federal Office for Statistics tells Hydrogen Insight.

In comparison, the central European state registered 40,507 battery-electric vehicles (BEVs) in 2023.

Gen Z are increasingly getting further apart in their ideological opinions, polls keep showing.

While women aged 18 and 29 have gotten more liberal in their beliefs every year, young men haven't and are less likely to care about political issues or participate in protests, according to an analysis by Daniel Cox, the director of the Survey Center on American Life.

Half of young men also believe they face some kind of discrimination, and less than half identify as feminists. Only half support the #MeToo movement, compared to nearly three-quarters of women.

Sharing the data, journalist and lawyer Imani Gandy commented on the pattern, saying: "YouTube algorithms are turning young men into sociopaths."

A Houthi anti-ship cruise missile fired into the Red Sea came within a mile of a US Navy destroyer on Tuesday, a report said, close enough that the American warship turned to its close-in weapons system — a last line of defense.

Most missiles are shot down farther out. This was the closest that a Houthi attack had come to an American warship, four US officials told CNN, which reported additional details of the incident on Wednesday.

US Central Command initially said on Tuesday that around 11:30 p.m. local time, the Houthis fired a single anti-ship cruise missile from Yemen toward the Red Sea, and it was shot down by USS Gravely.