Equatorial temperatures spiked, making much of the land too hot for life. Meanwhile, the oceans became acidic and most of the creatures in them suffocated from lack of oxygen. Known as the Permian-Triassic mass extinction or the "Great Dying," it ultimately destroyed more than 90% of ocean life and 70% of terrestrial species.

However, in a corner of what is now China, a refuge of pollen-producing plants avoided that fate and created an oasis for surviving animals. Research suggests that this was not the only place where plants were able to weather catastrophic climate change during the Great Dying, and that plants may have been better able to withstand the extinction event than other organisms.

"Plants do indeed sometimes have a lot of resilience because they can't move individually, and even as a population, they're not very good at moving," Chris Thomas, an ecologist and evolutionary biologist at the University of York in the U.K., told Live Science. As a result, many plants have evolved mechanisms to survive in place despite difficult conditions, he said.

As climate change raises global temperatures and throws ecosystems into upheaval, plants will need to draw once more upon this resilience. Many plant species have evolved unique adaptations that help them weather harsh conditions. Experts told Live Science that these adaptations — along with a hefty dose of luck — will now decide the difference between survival and extinction.

Growing with the flow

Unlike most animals, many plants have the ability to regenerate limbs — and those limbs can make them better able to adapt to new environment conditions. Plants in general have higher developmental plasticity than animals, which means that they have greater flexibility to change how their cells and tissues grow and develop.

"Many plants have what we call indeterminate growth and modular body plans," Amy Angert, a botanist at the University of British Columbia in Canada, told Live Science. Indeterminate growth means that an organism continues to grow and develop indefinitely throughout its lifespan.

"If we lost an arm, it would be gone forever. But on plants, if you cut off a branch, they can sprout new ones and those new ones can then receive signals from the current environment instead of being stuck with sort of developmental programs from the past environment."

For example, researchers found that resprouts on holm oak trees (Quercus ilex) are better able to cope with drought than those that had not resprouted.

And because buds can go dormant, many plant species can resprout after catastrophic events, such as fire. Cape Floristic Region in South Africa, for example, is the smallest of the world's six recognized floral kingdoms, and most of its plant species depend on fire — its plants resprout after fire and many of their seeds require fire to germinate.

Some plants, such as the Snow Gum (​​Eucalyptus pauciflora), have a thick layer of insulating bark to protect their buds, while others like stinging nettles (Urtica dioica) bury them underground in a "bud bank". The soil insulates the seed's buds from extreme heat and cold and protects most of the plant from life-threatening conditions. This widespread adaptation allows herbaceous plants to endure through the winter and plants with bulbs to hide their tissues from the ravages of fire.

Storing seeds for better times

Plants can also store seeds underground when times are difficult. Almost 350,000 plant species produce seeds. For most of these species, the seeds contain dormant tiny versions of the young plant, with all the structures that will turn into leaves and roots.

"Seeds can live essentially in stasis in the soil," Daniel Anstett, an evolutionary ecologist at Cornell University, told Live Science. "You can have the seed bank where certain seeds might come back, and there's access to the backward library of genetic information that many plants can ultimately draw upon."

Seed banks are a vital tool for resilience in many plant species. They create the opportunity for metabolically inactive individuals to reanimate when environmental conditions improve, according to a 2021 paper published in the journal Nature Communications. "When lucky, at least some of these individuals will awaken in the future when the environment is more conducive for growth and reproduction," the authors wrote.

Rapid evolution

Seedbanks can also be reservoirs of genetic diversity, which is integral to being able to adapt to new environments.

"The raw material for adaptation comes from genetic variation," said Angert. "Genetic variation is larger in large populations, and genetic variation can be shared between populations as the environment changes — if individuals can disperse successfully between them."

In a paper published in journal Science earlier this year, researchers, including Angert and Anstett, showed rapid evolution saved scarlet monkey flower (Erythranthe cardinalis) populations from prolonged drought in the U.S. and Mexico between 2010 and 2018.

"They can either grow really fast, flower and put out seeds before the fall drought takes effect, or they can grow much more slowly and bunker down,” Anstett explained.

The researchers sequenced the genomes of 55 scarlet monkeyflower populations to find areas within their genomes linked to coping with stress and drought. They tracked the populations and how they changed over the period. Some populations experienced rapid evolution to cope with the changing environment.

They found that, based on populations’ genetic diversity, they could predict whether a population would be able to survive the drought — even before it started.

While this is only one plant species, Anstett believes it could be true of other organisms too.

Flexible photosynthesis

Some plants are able to transform how they produce energy to endure a changing environment. This is what Zhen Xu, a paleobotanist at the University of Leeds in the U.K, thinks allowed some plant species to survive the Permian-Triassic mass extinction and might become increasingly important for plants in today's changing climate.

Plants use photosynthesis to convert carbon dioxide and water into sugars and oxygen, and use stomata, or small pores on their leaf surface, to regulate the amount of carbon dioxide entering the plant.

Many plants open their stomata during the day to let in CO₂ and release oxygen. Others use CAM photosynthesis, which stands for "Crassulacean acid metabolism," to close their stomata during the day and protect themselves from the heat. At night, they absorb CO₂ and transform it into an acid, which they store in their tissues to be used to make sugars during the day.

"CAM photosynthesis is very common in present day desert plants, like the cactus and succulents," Xu told Live Science. "It's a very smart way to escape from the high temperature or aridity during the daytime."

In a study published in journal Nature Ecology & Evolution earlier this year, Xu and colleagues showed that plants that used CAM photosynthesis had an advantage during the Permian-Triassic mass extinction.

They found that Lycophytes, or are ancient vascular plants, switched to CAM photosynthesis around the time of the mass extinction. "We think CAM photosynthesis may be the special strategy to survive" and allowed these plants to dominate after the mass extinction, Xu said.

Hopeful monsters

Some plants go to even more extreme lengths. During cataclysmic events, plants have turned into "hopeful monsters" to survive environmental upheaval, past research shows.

In nine separate events over the past 150 million years, many flowering plants duplicated their whole genome to give themselves a better chance of survival, according to research published in journal Cell earlier this year. The duplicate genome gives them more opportunities to evolve and adapt to challenging environmental conditions.

"We see clusterings of whole genome duplications in time, and every time it corresponds with a described, important geological event, whether it's a global cooling period, whether it's a global warming period, or whether there's an extinction event," study co-author Yves Van de Peer, a genome biologist at Ghent University in Belgium, told Live Science at the time.

Boils down to luck

Still, the survival of specific plant populations or species often boils down to luck, experts told Live Science.

Plants "essentially have this broad toolkit" but "some of the plants have some pathways, and other plants have others, and some have some traits, and some have others", Anstett said. Whether the particular tools they have will help depends on the conditions they face.

During the Triassic-Permian mass extinction, the plants in refugia in China (and elsewhere) were in the right place at the right time, with the right suite of potential adaptations at their disposal and enough genetic variety to tap into them.

The same holds true for modern-day species facing a changing climate and potential extinction. Angert said there are ways to make plant species "luckier" in the years ahead, such as connecting fragmented populations to increase genetic diversity, which increases the suite of potential tools at a plant species' disposal.

"The best thing we could do is to leave larger and better connected populations on the landscape," she said.

Anstett agreed. "If populations become really disconnected, then potentially we're eroding away whatever toolkit that these plants have to be able to adapt."

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'> Will plants survive climate change? The 'Great Dying' reveals clues about their resilience.

Christoforos Kotsakis, a professor of geodesy at the Aristotle University of Thessaloniki in Greece, developed a new method for analyzing GNSS data to better capture the changes in the planet's surface. He found that the poles are rising and the equator's bulge has been shrinking, each by about 0.04 inch (1 millimeter) per year between 2011 to 2015. That's a small number, considering Earth's diameter at the equator is about 7,926 miles (12,756 kilometers). But that change is bigger than between 1997-2000, when Earth was becoming about 0.02 inch (0.5 mm) rounder per year. This means Earth's shape is rounding at 0.016 inch (0.4 mm) more per year with each decade that passes.

The shift is being driven by polar ice melt, which takes pressure off the Earth's crust and allows it to rise slowly, similar to how rising bread dough springs back after you press a finger into it, Kotsakis reported. Meanwhile, increased mass toward the equator puts pressure on the crust there, reducing its bulge. However, there's a catch: When considering the solid Earth and the ocean together, the planet is getting flatter by about 0.03 inches (0.8 mm) a year because the ocean is getting bulgier at the equator as water shifts away from the poles. This 'water weight' overwhelms the rounding happening in the rock below.

These shifts are also slowing Earth's rotation, other research has shown.

Researchers also track Earth's changing shape using measurements of its gravity field, which varies depending on the mass of particular regions. GNSS changes and gravity field measurements don't match up perfectly, Kotsakis found, which indicates that the planet's shape and gravity field aren't in perfect lockstep. However, the two methods can be used together to track the major effects of climate change, especially the melting of Greenland and Antarctica and the varying movements of ocean water.

'> Climate change is literally altering the shape of our planet

"The Upper Colorado River Basin has historically been considered more resilient because it receives more precipitation, particularly snowfall in the Rocky Mountains," Oyedele told Live Science in an email. "I think the important takeaway is that we should not assume that the Upper Basin will remain relatively resilient simply because it has historically received more precipitation and snowmelt."

The Lower Basin comprises parts of Nevada, California and Arizona. Less rain and snowfall means the Lower Basin naturally has less groundwater recharge, or less replenishment from other water sources, than the Upper Basin. On top of that, the Lower Basin generally has higher evaporation rates and substantial water demands, given that roughly 30 million of the 40 million people that depend on the Colorado River for water live in the Lower Basin, Oyedele said.

In the new study, published Oct. 13 in the journal Water Resources Research, researchers used satellite and hydrological data to estimate groundwater depletion across the Colorado River Basin between 2004 and 2023. The data included measurements of surface water, soil moisture and snow-water storage, as well as observations from the Gravity Recovery and Climate Experiment mission and its successor, called the Follow-On.

The results showed that groundwater depletion has been a persistent problem in the Colorado River Basin over the past two decades, but losses accelerated in 2019. The three-year drought that began in 2020 is the principal cause of this, because it shrank the snowpack in the Rocky Mountains, increased evaporation and boosted water demand across the basin, Oyedele said.

During the drought between 2020 and 2022, the Upper Basin lost around 4.2 cubic miles (17.5 cubic kilometers) of groundwater, while the Lower Basin lost about 2.3 cubic miles (9.4 cubic km). In total, the Colorado River Basin lost 14 cubic miles (58.3 cubic km) of groundwater ‪—‬ equivalent to 25 million Olympic-size swimming pools' worth of water ‪—‬ during the study period, between 2004 and 2023.

It's unclear why the deficit is so much higher in the Upper Basin than in the Lower Basin, but the Upper Basin's proximity to and dependence on the mountains for aquifer recharge probably didn't help, Oyedele said. As snow melts, some of it replenishes groundwater, so a reduction in snowfall between 2020 and 2022 would have affected the Upper Basin particularly badly, she noted.

The Upper Basin also recorded more aquifer recharge during wet periods before the drought than the Lower Basin did, so it's possible that the pronounced decline during the drought was linked to a higher initial amount of groundwater in the Upper Basin, Oyedele said.

Next, the researchers used advanced statistical methods to explore the relationship between groundwater and surface water in the Colorado River Basin. Due to global warming and the overallocation of the Colorado River's water in a 1922 document, the river's flow is now 35% less than it was on average in the 20th century. Water scarcity in the basin has reached alarming levels, according to the study, and Lake Mead and Lake Powell, the two largest reservoirs in the U.S., dropped to record lows in August.

The team found that in the Upper Basin, groundwater levels evolve in the same direction as surface water, but with a slight delay. This suggests groundwater losses occur due to a lack of recharge and more aquifer pumping during periods of drought, when surface water levels drop. In the Lower Basin, however, this link is weaker and more complex. The results showed that groundwater losses sometimes preceded surface water declines during the study period, suggesting that groundwater depletion is not simply tied to less surface water trickling into the ground or to humans extracting groundwater when there's less surface water available. Instead, groundwater is consistently being overused, Oyedele said.

"This distinction is important because it suggests that groundwater depletion is not simply a direct response to surface-water shortages," she said. "Human water use, particularly sustained groundwater extraction, may also play a significant role."

Looking ahead, it's hard to tell if the Upper Basin will continue to lose more groundwater than the Lower Basin and what that would mean for the region, Oyedele said. What seems clear, however, is that the Upper Basin is more vulnerable to drought than experts had thought.

"Continued warming, changes in snowpack, prolonged drought, and increasing water demand could place additional pressure on groundwater resources across both basins," Oyedele said. However, future groundwater responses will depend on several factors, including precipitation, snowmelt, water use and management decisions, she added.

On the management side, Oyedele suggested tackling groundwater and surface water together rather than as two separate resources. Groundwater helps to sustain river flows, and rivers can recharge aquifers ‪—‬ so the two are interconnected. Groundwater often serves as a backup during drought, but it shouldn't be treated as an unlimited reserve, she said.

'> Surprising new pattern of groundwater loss may signal a turning point for the Colorado River Basin James Webb Space Telescope (JWST). The metals may offer new clues about how Earth got its share of heavy elements — but it could also make one of the greatest mysteries about our local black hole even harder to solve.

In astronomy, metals refer to any element heavier than hydrogen or helium, with common examples including oxygen, carbon, iron or gold. These elements are forged through nuclear fusion in the hearts of stars that are reaching the ends of their lives, before being sprayed into space and incorporated into new generations of stars.

Scientists say the material spotted by JWST likely came from supernovas ‪—‬ stellar explosions that blasted the metal into the region around Sagittarius A (Sgr A*), the monster black hole in the middle of our galaxy.

The metals, detected as gas, appear to have the same composition as several nearby stars, which suggests both the stars and the gas originated at the same time. Researchers shared the observations in a paper published Oct. 19 in The Astronomical Journal, following up on work published in The Astrophysical Journal in May.

"We know there's a black hole at the centre of our galaxy pulling material into itself, but we see that it's eating a lot less material than other supermassive black holes, and more slowly," Nicole Ford, first author of the new paper and a doctoral student in astrophysics at McGill University in Montreal, said in a statement. "Part of understanding why this is happening means looking at the properties of the materials available for it to consume, including gas, dust and the stars orbiting around it."

JWST orbits at Lagrange point 2, which is about 1 million miles (1.5 million kilometers) from Earth in the opposite direction of the sun. The telescope identified the heat signatures of specific gas clouds billowing near the black hole, as well as the metal content within those clouds.

"These findings could advance understanding of how metals are distributed around supermassive black holes in more distant galaxies, as well as the processes that supplied Earth with many of these elements," McGill researchers said in the statement. The metals' presence "influences how quickly gases cool, which in turn influences how readily the gas can be drawn into a black hole," they added.

The previous study in The Astrophysical Journal showed that gas emissions near the black hole have been influenced by conditions in the local clouds. Unfortunately, this means the gas alone cannot serve as a proxy for how often the black hole has been active, the researchers said.

See how much you know about black holes with our black hole quiz!

'> James Webb telescope discovers surprising trove of metals around the Milky Way's supermassive black hole statement from the University of Oslo's Museum of Cultural History.

"Here we have a coin bearing the king's portrait and a cross, with another cross on the reverse," University of Oslo coin expert Svein Gullbekk said in the statement. "It is a Christianisation coin on a grand scale."

Olaf is credited with establishing Christianity in Norway — an early step toward its full conversion about a generation later.

"We can see how King Olaf used coinage to legitimise the new faith and to establish himself as a Christian king of European standing," Gullbekk said. "This is branding."

Viking king

Haraldsson learned about Christianity when he joined Viking raids against England and France as a young man, and he was baptized in the French city of Rouen in about 1013, according to the statement.

He became Norway's king in 1015, and in about 1024 proclaimed that only Christianity would be legal, according to the University of Bergen. Much of Norway, however, remained faithful to the Norse gods during his rule, especially around the central Trøndelag region and in the eastern parts of the country.

But Olaf was made a Christian saint shortly after his death in 1030. He is now recognized as one of the first Christian kings of Norway and the first Norwegian king to issue coins in his own name.

The newfound coin is part of the Mørstad Hoard, which was discovered near the village of Rena in April. At that time, the buried hoard was described as the largest ever found in Norway and was estimated to contain almost 3,000 silver coins. However, subsequent research has determined that it includes anywhere from 5,500 to more than 6,000 coins, the statement said.

Mistaken identity

Anne Skogsfjord, a museum researcher charged with cataloging the coins, thought the Olaf coin was an Anglo-Saxon penny at first. But then she read the inscription and realized it was minted in Norway under Olaf.

"I could see that it read ONLAF R+ NORMANORV. … Could this really be a coin of Olaf Haraldsson that I was holding?" Skogsfjord said in the statement. "And it was! It was a very special moment."

The coin was struck between about 1024 and 1028, near the end of the Viking Age, and circulated for 20 to 25 years before someone deposited it in the hoard, the statement said.

Although the minting of the coin was a political and religious act, the coin also seems to have been used as currency; both sides bear numerous small cut marks, which was a common way of determining whether a coin was made completely of silver.

Gullbekk said Haraldsson himself had decided what the coins would look like and may have been present when they were minted.

"It is entirely possible that this very coin from Mørstad was once held in the king's own hand," he said in the statement.

See how much you know about ancient norsemen with our Viking quiz!

'> Extremely rare Viking Age coin from the reign of 'Olaf the Holy' may have been 'held in the king's own hand'