Scientists discovered that Antarctica’s ice sheet became dramatically more climate-sensitive after crossing a critical threshold one million years ago. A new study published in Nature Geoscience suggests that Antarctica’s massive ice sheet underwent a major change about one million years ago, becoming far more responsive to shifts in Earth’s climate. The research, led by scientists [...]

Scientists say melting sea ice may have pushed the Arctic Ocean past a tipping point, triggering changes that could reshape marine life for decades. Scientists have identified what appears to be a major and potentially irreversible change in the Arctic Ocean. According to a new study, climate-driven sea ice loss has altered the region’s chemistry [...]

Iran is experiencing "water bankruptcy" that stems from decades of broken water governance and aggressive policies, and the current war is exacerbating the crisis.

Fingal's Cave is a hollow inside the Scottish island of Staffa that is characterized by massive, interlocking hexagonal columns of volcanic rock and astonishing acoustics.

Fires from March 7 airstrikes created a sulfur dioxide plume spanning 185,000 square miles.

Researchers have warned that the Thwaites Glacier, one of the largest glaciers in the world, is about to lose its eastern ice shelf. We spoke to marine geophysicist Robert Larter about what this means for the "Doomsday Glacier."

West Antarctica's "Doomsday Glacier" is on the brink of losing its ice shelf, further compromising the already melting ice mass and threatening to unleash devastating sea-level rises.

A 2015 satellite photo shows a series of golden tendrils surrounding Ghana's Lake Bosumtwi, which is considered sacred to the local Asante people. The lake and its surroundings were shaped by a massive meteor impact around 1 million years ago.

Jupiter dominates the Solar System’s architecture. At about 318 times Earth’s mass and orbiting far beyond Mars, it acts as...

The post If Jupiter Disappeared Would Earth Face More Asteroid Hits? appeared first on Curiosmos.

If Earth disappeared instantaneously, the first thing that would not happen is a crash. The Moon is not “hanging” over...

The post If Earth Vanishes What Happens to the Moon? appeared first on Curiosmos.

Iran is experiencing "water bankruptcy" that stems from decades of broken water governance and aggressive policies, and the current war is exacerbating the crisis.

Even the satellites are seeing red.

Even the satellites are seeing red.

Fingal's Cave is a hollow inside the Scottish island of Staffa that is characterized by massive, interlocking hexagonal columns of volcanic rock and astonishing acoustics.

Fires from March 7 airstrikes created a sulfur dioxide plume spanning 185,000 square miles.

As a species, humans like it cold.

Even now, we live in an “ice age.” Though the term may bring to mind saber-toothed cats and woolly mammoths, such ages are defined by ice caps at the poles. And for most of its 4.6-billion-year history, our planet was too warm — sometimes far too warm — for polar ice.

For more eons than not, Earth has ranged from steamy to downright hellish.

A look back at Earth’s history shows us how fragile and fleeting our current moment is. Between its fiery infancy and its (for now) chilly present, Earth’s climate has taken many forms.

Learning why Earth’s climate changed in the past — and what happened to life when it did — can help us understand where we are today. We know our species evolved in the cold. Yet human-caused warming has set our planet onto a hot new path.

What can the past teach us about where we might be headed?

Hadean Eon: Hell on Earth

Earth’s turbulent infancy began some 4.6 billion years ago. Clumps of material formed out of the disk of hot dust and gas that swirled around the young sun.

About 100 million years later, a Mars-sized rock called Theia smacked into the young Earth. That run-in released the energy equivalent of trillions of hydrogen bombs. It was enough “to pretty much vaporize most of Theia and melt what becomes the Earth,” says Norman Sleep. He’s a planetary scientist at Stanford University in California.

That collision left the planet a hellish ocean of magma beneath a sky of rock vapor. Weak sunlight beat down on a cracked crust of black-gray basalt. In the sky hung a second ball of glowing magma: the moon. This orb had formed from the impact debris, maybe in just a few hours.

This was the Hadean Eon — the hottest Earth has ever been. Over the next 1,000 years, Earth cooled somewhat. Rock vapor in the atmosphere would have condensed and fallen — think showers of lava or perhaps flakes of rocky snow.

The magma ocean solidified more slowly. The young moon heated Earth via the force of its gravity. This kneaded Earth’s interior and kept the planet molten for perhaps tens of millions of years.

Finally, that magma ocean crystallized into rock.

This marked a turning point for our planet, Sleep says. The sun became its most important source of energy. Ever since, Earth’s climate has been driven by how much solar energy it gets, reflects and retains.

Archean Eon: Earth’s thermostat turns on

The Archean Eon stretched from 4 billion to 2.5 billion years ago. It began when Earth’s surface cooled enough to form solid rock. Back then, the young sun was only about 70 to 80 percent as bright as it is today. Its energy alone would not have been enough to keep the planet as warm as it was.

In theory, Earth should have cooled enough to ice over. But it didn’t. Why?

As the Earth cooled, it produced a thick, steamy atmosphere. Water vapor fell as rain. A lot of rain. It poured until Earth’s surface drowned beneath a global ocean once more — this time, of water.

The cooling planet also released greenhouse gases such as carbon dioxide (CO₂) and methane. These acted like a blanket to trap heat around Earth. “There was a bigger greenhouse effect” than today, says David Catling. A planetary scientist, he works at the University of Washington in Seattle.

At around the same time, another major change kicked in: the carbon cycle. This acts as the planet’s natural thermostat.

Here’s how it works. Through the greenhouse effect, CO₂ in the atmosphere warms Earth’s surface. A process called chemical weathering traps some of that CO₂ in minerals called carbonates. They can stay trapped in rocks for a long time. Over hundreds of thousands of years, however, the movements of Earth’s tectonic plates recycle Earth’s surface into its interior.

In Earth’s mantle, the carbonates break down. Their carbon then gets belched back up by volcanoes as CO₂. Back in the air, it once again warms the planet.

This cycle is sensitive to temperature: Chemical weathering speeds up in warm climates and slows in cold ones. The overall effect helps keep temps fairly stable.

By the early Archean, the carbon cycle had locked away enough CO₂ to bring temps into a range habitable for life. Modeling studies suggest the planet ranged between a frosty zero degrees and a toasty 40° Celsius (32° to 104° Fahrenheit). In fact, the earliest signs of life date to this period.

Snowball Earth: A deep freeze

Between 2.4 billion and 2.1 billion years ago, Earth froze over. Thick sheets of ice encased the planet from pole to equator. Temperatures may have plummeted to as low as -50 °C (-58 °F) and stayed low for tens of millions of years.

This deep freeze was one of several icy episodes called Snowball Earths. They bookend the otherwise toasty Proterozoic (PRO-tur-eh-ZOH-ik) Eon. It stretched from 2.5 billion to 541 million years ago.

The ice sheets grew through a runaway feedback loop. Sparkling white ice reflects more sunlight than does land or water. That lowers temperatures, which encourages even more ice to form. Once polar ice creeps past a latitude of about 30° North or South, the planet will become a snowball.

“Once you reach that tipping point in the area of sea ice, then it takes on the order of 200 or 300 years to reach the fully [iced-over] state,” says field geologist Paul Hoffman of the University of Victoria in Canada. “That’s pretty quick on a geological time scale.”

Glacial rock deposits that formed at the equator are evidence that the Snowballs happened. But how they started remains a mystery. One theory blames biology.

Clues from ancient rocks suggest the Proterozoic oceans bloomed with photosynthetic organisms. They would have released lots of oxygen into the air. Oxygen breaks down methane. So it ate away the methane blanket that had kept Earth warm for 1.5 billion years.

The carbon cycle wouldn’t have been able to keep up, Catling says. Eventually, “you could grow ice sheets and make a Snowball Earth.”

Earth’s thermostat won’t let a Snowball go on forever. As the land freezes over, chemical weathering shuts down. But volcanoes don’t. They keep pumping CO₂ into the atmosphere. Eventually, the greenhouse effect will thaw out the planet. As that ice melts, the planet will reflect less sunlight. The bonus energy will warm the planet even more. Suddenly, the ice retreats.

Permian Period: Warming and mass extinction

Today, ice persists at Earth’s poles. These “icehouse” periods are few and far between in Earth’s history.

The last one was in the early Permian Period. This was about 300 million years ago. The average temperature was probably 15 degrees C (27 degrees F) cooler than today. Earth might have looked a bit like it did 20,000 years ago. That’s when woolly mammoths roamed Europe.

This cold spell lasted for 105 million years. Then climate change transformed the land into a scorched — and possibly toxic — wasteland.

Over some 20 million years, things started getting less friendly to life, says Neil Tabor. He’s a geologist at Southern Methodist University in Dallas, Texas. Why? In part this was thanks to the assembly of the supercontinent Pangaea. As more land crammed together, coastlines shrunk and sea levels dropped. Coastal areas dried out, and throughout the parched continental interior, temperatures swung wildly.

Then huge volcanoes in what’s now Siberia started erupting. They didn’t stop for 1 million years.

Over that time, they spewed enough lava to bury an area as large as the continental United States under 50 meters (160 feet) of molten rock! With all that lava came lots and lots more CO₂. And that made surface temperatures soar.

In a geologic blink — perhaps as quickly as 60,000 years — average temps jumped as much as 10 degrees C (18 degrees F), reaching around 30 °C (90 °F). Oceans sweltered and grew too sluggish to circulate oxygen. Much marine life suffocated.

Bacteria that thrived in the oxygen-deprived depths poisoned the water with hydrogen sulfide. That deadly gas might have bubbled up to poison the land, too. Volcanic gas mixed with water to rain acid on the barren, dusty wastes.

On land, there were “toxic, salty, shallow acid lakes,” says Kathleen Benison. “And lots of windblown, red dust.” A geologist, Benison studies the Permian climate. She works at West Virginia University in Morgantown.

Near the end of the Permian, some 252 million years ago, Pangaea was a sunbaked, dusty wasteland. Daytime air temperatures in the tropics hovered around 50 °C (122 °F). On the hottest days, they climbed to 73 °C (163 °F) — hot enough to destroy proteins. Any living thing that couldn’t flee to the poles would have been cooked alive.

The resulting mass extinction was the worst our planet has ever seen. In a few hundred thousand years, 70 percent of species on land disappeared. The seas were hit even harder: 95 percent of marine species died out.

It may have taken millions of years for life to recover.

The Permian offers a cautionary tale for our current moment.

“We’re still technically in an icehouse, but we’re rapidly going towards a greenhouse,” Benison says. “Looking back at the [end of the Permian] is a good way to try to say what happens with these big changes. And not just what happens with climate, but what happens to life.”

Cretaceous Period: Gradual heat

A greenhouse doesn’t always lead to mass extinctions, though. By 90 million years ago in the Cretaceous Period, the planet was a lush jungle world. Vast swaths of the continents were flooded by shallow seas. In some areas, carnivorous dinosaurs like Spinosaurus prowled the shores. At 36 °C (97 °F), Earth’s average surface temps hovered around human body temperature. Even polar seawater was a soupy 27 °C (81 °F).

Despite that, this period saw “no mass extinction,” says Brian Huber. He’s a geologist at the Smithsonian National Museum of Natural History in Washington, D.C.

Huber was part of a team that charted Earth’s surface temps for the last 485 million years. This timeline revealed a super-hot greenhouse environment. In fact, it was the hottest Earth has ever been since the evolution of any life more complex than a microbe.

Scientists aren’t sure what drove temperatures so high. But it’s clear that the rise was fairly gradual.

There was no 10-degree jump like the one that rocked the Permian. Instead, Earth had been hot for a long time. In fact, it never really cooled down after the Permian extinction. Average surface temps worldwide mostly stayed above 20 °C (68 °F). (For comparison, that’s just 5 degrees C [9 degrees F] hotter than it was in 2024.) And the poles were largely ice-free throughout the dinosaurs’ nearly 180-million-year reign.

So perhaps the Permian extinction was so massive because of the swing from icehouse to greenhouse. An abrupt change may have put ecosystems under additional stress. That would be bad news, considering what’s happening today.

What’s next for Earth’s climate?

Following a 50-million-year cooling, we’re now in an icehouse period.

The time 55 million years ago was known as the Paleocene-Eocene Thermal Maximum, or PETM. It was the hottest period in the history of our Earth — that planet with the continents and ecosystems we know today.

Atmospheric CO₂ levels were high, and temps reached an average of up to 34 °C (93 °F). Unlike us, creatures that lived back then were used to an iceless planet. There was no mass extinction, but ecosystems shifted. And many species died out in parts of their ranges. Some disappeared completely.

Since the PETM, Earth has been cooling down. This could be due in large part to the rise of the Himalayan mountain range in Asia. Chemical weathering of all that fresh rock could have driven steady drops in atmospheric CO₂. By 34 million years ago, Antarctica was cold enough for year-round ice. And by 800,000 years ago, CO₂ levels fell below about 300 parts per million (ppm).

But in just the past 200 years, human activities have driven airborne CO₂ levels back up. Emissions — such as from coal-fired power plants and gas-fueled cars — have nearly doubled CO₂ levels, from 280 ppm to 426 ppm. Average temperatures have ticked up by 1.47 degrees C (2.65 degrees F).

If nothing major changes in our approach to climate change, this will be just the beginning. By 2100, CO₂ levels could reach 600 ppm. Some climate models show it could soar above 1,000 ppm. That could result in average temperatures 4 degrees C (7 degrees F) warmer than in preindustrial times.

If we’d been around in the PETM, we’d have had to migrate to the poles to survive. That’s bad news for today’s humans. Cities can’t exactly get up and move. By the end of this century, billions of people will routinely face heat and humidity extremes beyond the limits of human survival.

The next glacial period will start later than expected, if at all. And by 2500, four-tenths of all land will have become unsuitable for its current biome, scientists predict.

This glimpse of a likely future is informed by our past. And it gives us the chance to choose a different path. Cutting carbon emissions can still slow warming and its impacts.

If extreme warming occurs, it would end the world as we know it. But it would not be the end of the world.

Even if we trigger a climate catastrophe on the scale of the Permian mass extinction, Earth’s history shows that the planet will recover and life will eventually thrive again. The carbon thermostat will correct our error — but it is very slow. We can’t wait millions of years for it to fix climate change for us.

Researchers have warned that the Thwaites Glacier, one of the largest glaciers in the world, is about to lose its eastern ice shelf. We spoke to marine geophysicist Robert Larter about what this means for the "Doomsday Glacier."

West Antarctica's "Doomsday Glacier" is on the brink of losing its ice shelf, further compromising the already melting ice mass and threatening to unleash devastating sea-level rises.

About 400 million years ago, the population of plants with vein systems for transferring water and nutrients, called vascular land plants, exploded. Soon thereafter, rocks from some continental magmas showed notable shifts in their chemical compositions. Geologists have suggested that these magma changes happened worldwide, but some argue that the data might be biased because some geographic regions have more samples to analyze than others. A new research team recently tested whether these magmatic changes occurred on a global scale, versus in isolated mountain belts or volcanic islands. 

Geologists use the chemistry of rocks formed from magma to understand a magma’s history. In particular, a mineral called zircon that forms from cooling magma preserves chemical clues about where the magma came from and what it interacted with. To test whether magma changes were global or local, the authors needed data ranging from the equator to the poles. Continents have shifted over the past 400 million years, so scientists use the latitude a rock had when it formed, called its paleolatitude, to compare samples from different parts of ancient Earth. To understand magma histories worldwide, the team used publicly available chemical data from zircons in magmatic rocks that formed across a wide spread of paleolatitudes.

Chemical elements with the same number of protons but different numbers of neutrons are called isotopes with different masses. To discern how plants influenced magma, the researchers analyzed 2 different isotope signals preserved in the zircons. The first isotope signal comes from the ratio of the heavy to light oxygen isotopes, which increases when sediment mixes into magma. Scientists refer to this value as δ¹⁸O, pronounced “delta 18-O.” 

The second isotope signal comes from the element hafnium, denoted Hf. Geologists use hafnium to estimate how long ago magmas melted and separated from the mantle. Zircon contains 2 Hf isotopes, one of which is stable and one of which is produced by radioactive decay. Because this decay happens over billions of years, the ratio between the 2 Hf isotopes over time shifts only slightly. Geologists express these tiny differences using a shorthand called εHf, pronounced “epsilon hafnium,” which shows how much a magma’s Hf signature has changed from Earth’s original mantle. Lower εHf values indicate magmas that incorporated older crustal rock, while higher εHf values reflect mantle sources.

The researchers found that δ¹⁸O values increased as εHf values decreased in these zircons. They concluded that this trend indicates increasing amounts of land-derived sediment in magmas, corresponding with the evolution of land plants. They suggested that land plants altered the ancient landscape, changing how sediments weathered and moved over land. 

To explore this pattern in detail, the team focused on the Andes Mountains, a region that preserves a long history of magmatic activity across a long span of space and time. Using a database, they accessed isotope data from zircon samples collected in the Andes Mountains by dozens of other research groups. These samples covered 32 degrees of modern latitude and 520 million years of Earth’s history, offering a broad window into how magma chemistry changed during that time.

They found that zircons older than 450 million years had no relationship between their εHf and δ¹⁸O values. However, in zircons younger than 450 million years, δ¹⁸O increased as εHf decreased. The researchers saw this pattern in magmas that formed along the edge of the continent, where one tectonic plate sinks below the other, called a subduction zone. They also saw this pattern in magmas that formed inland, away from the subduction zone, around 200 million years ago during the breakup of the supercontinent Pangaea.

 They found similar results in published zircon isotope data from igneous rocks in China, the Caribbean, Antarctica, Madagascar, and Tasmania. Zircons from each region showed the same relationship as zircons in the Andes. Since paleolatitude can also reflect ancient climate, the researchers compared the ratio of εHf and δ¹⁸O, written as εHf/δ¹⁸O, with paleolatitude to test whether ancient climate zones influenced magma chemistry. They found no link between paleolatitude and εHf/δ¹⁸O. 

With these results in mind, the researchers concluded that the relationship between εHf and δ¹⁸O shifted worldwide after vascular land plants evolved. They argued that as plants spread across the continents, their roots accelerated the breakdown of rocks. This accelerated weathering produced large amounts of sediment that washed into ocean basins and was eventually subducted into the mantle, forever changing the chemistry of magma formed there. They suggested that this chain of events illustrates how life on Earth’s surface can drive changes deep within the planet. 

The post Plants changed the chemistry of magmas appeared first on Sciworthy.

Some clouds are flat. Others are puffy. Some are pretty and turn orange or red at sunrise or sunset. Others signal stormy weather and can produce precipitation, such as rain, hail or snow.

Meteorologists, or weather forecasters, spend lots of time predicting clouds. That’s because clouds are behind all storm systems — from tornadoes and hurricanes to rain and snowstorms. 

Technically speaking, a cloud is nothing more than a clump of aerosols — small solid or liquid particles suspended in the air. In some clouds, those aerosols can be bits of wildfire smoke or even desert dust.

But most clouds are made of water. A typical cloud droplet is only 20 micrometers (0.00008 inch) in diameter. That’s less than a thousandth the size of an average raindrop. Since cloud droplets are so tiny, they are very light. And that’s part of why clouds float.

These water droplets start to form through evaporation. Evaporation occurs when liquid water molecules become energized and change phase into a gas. Energy from the sun heats Earth’s surface — including water molecules in the ground as well as in oceans, lakes and rivers. Some water molecules become warmer, and more energized, than others. The most energized ones become a gas, known as water vapor.

Most air is made of N₂ — or two nitrogen atoms clumped together. A molecule of water vapor weighs less than this nitrogen molecule. That’s also partly why clouds float.

Why can we see clouds?

We can’t see water vapor on its own. Clouds become visible when water vapor condenses, or transforms back into a liquid. That happens when water vapor rises high enough in the atmosphere that it cools.

Gravity pulls those droplets toward the ground. But they’re so tiny that warm rising air keeps them suspended aloft. And even if a single cloud weighs tens of millions of kilograms (pounds), the air outside the cloud is a bit heavier still. So the cloud floats.

Sometimes, water vapor rises extra high. At 12,200 meters (40,000 feet) above the ground, the average temperature is –57° Celsius (–71° Fahrenheit). Here, it’s too cold for water droplets to form. Any water turns into tiny ice crystals.

That’s why clouds at high altitudes aren’t puffy. They aren’t made of liquid droplets. Made of ice crystals, they’re wispy-looking.

Different types of clouds

Some clouds form near the ground. Fog is a cloud that forms on the ground.

“When we see fog, that is simply a cloud at the surface,” wrote Brandon Richards, a meteorologist for Spectrum News Texas in Austin, in a text message. “Fog happens when the air is saturated.” That means the air is holding as much water as it can. The extra water condenses, forming a cloud.

Fog is one type of stratus cloud. The word stratus comes from the Latin word for “layer.” Other stratus clouds may form a few thousand meters (feet) above the ground. They’re usually pretty flat.

In summer, the sky might host puffy clouds. It can be fun to look for shapes in these cumulus clouds. Such clouds usually form a couple kilometers (miles) above the ground. They come together when pockets of warm air rise.

The highest types of common clouds are cirrus. They form 9,100 meters (30,000 feet) or more above the ground. At that height, they’re made of ice crystals, which gives them a wispy, hairlike appearance.

Different types of clouds can be present at the same time. And some clouds are actually a combination of different cloud types. Cirrostratus clouds are wispy like cirrus clouds, but flat and layered like stratus clouds. Stratocumulus clouds are layered but a bit puffy.

Rare clouds

Some clouds form in weird ways. Consider noctilucent clouds. The term noctilucent comes from Latin words that mean “light at night.” Earth’s highest clouds, these form at heights of 76 to 85 kilometers (47 to 53 miles).

There’s little water vapor at such altitudes. So how can clouds form there? Meteor smoke!

Meteors burn up in this part of the atmosphere, leaving behind smoke particles. Water droplets can glom onto these particles and turn into ice crystals. And being so high, these clouds can catch sunlight even after the sun has set (at ground level). These clouds shimmer, like blue, glow-in-the-dark curtains.

Another type of strange cloud is the pyrocumulonimbus (PY-roh-KEW-mew-lo-NIM-bus), or smoke cloud. Wildfires can release lots of smoke. As smoke and hot gases rise, they can form a thundercloud. From these clouds, wildfires sometimes produce their own thunderstorms, windstorms — or even fire tornadoes.

Precipitation and thunderstorms

Precipitation happens when a cloud can’t hold any more water. Tiny, light cloud droplets coalesce, or merge, into bigger droplets. Those that become heavy enough will fall out as rain.

Something similar happens when it’s cold. Tiny, chilly water droplets merge to form ice crystals. That’s what makes snowflakes in the wintertime. Snow falls more slowly than raindrops. While raindrops plummet as fast as 10 meters per second (22.4 miles per hour), snowflakes tend to glide down at a pokey 0.4 to 1.8 meters per second (0.9 to 4 miles per hour).

Thunderstorms can produce dangerous precipitation. These storms come from cumulonimbus clouds. That’s the technical name for thunderclouds.

Thunderclouds start as cumulus clouds — puffy clouds fairly close to the ground. Warm, wet air helps them grow taller. Some thunderclouds can rise into towers 16 kilometers (10 miles) tall. While the tops of these clouds are made of ice, their bottoms consist of water droplets.

Cumulonimbus clouds can produce thunder and lighting. Because they’re tall, they can lift water droplets very high before they finally fall. That’s how hail forms. High-up water droplets can cool and freeze into an ice pellet. As more droplets freeze onto the pellet, the hailstone grows. Some thunderclouds can produce chunks of ice the size of baseballs or bigger.

The most extreme thunderclouds become supercells. That’s a thundercloud that rotates. Changing winds blow different layers of the cloud in different directions. That causes the entire cloud to spin. Supercells occasionally spawn tornadoes.

But there’s a catch. Sometimes, clouds can limit the intensity of storms. Why? “Clouds, even light wispy ones, can affect how much [sunshine] reaches the ground,” explains Joey Krastel. He’s a meteorologist for the Maryland Department of Emergency Management in Hanover.

If you look out from a plane window, you can sometimes see shadows on the ground cast by individual clouds. That’s one sign of how much sunlight clouds can keep from reaching the ground. With less sunlight, the Earth’s surface cools. Now there’s less energy to evaporate water. With less warm and wet air, storms can’t form as easily.

“During storm outbreaks, thick cloud cover can limit surface heating and reduce storm energy and potential,” Krastel wrote via text message.

That’s why the stormiest days often begin with sunshine. It seems strange to think that sunshine actually helps storms, but it’s true. The more the air is heated by sunlight, the more it can rise — and the bigger storms will grow!