Climate

Ecologist Akhil Javad felt the thrill of fieldwork quickly fade when he was faced with the prospect of scaling trees over five times his height. But for some of the trees he was studying in India’s Western Ghat mountains, that was the only way to take their temperature.

So, Javad got climbing. Sensors that he placed on leaves in the upper canopy are providing unprecedented insights into how tropical forests are weathering global warming. The findings suggest that the trees may be in better shape than scientists thought, he and colleagues report in the February Global Change Biology.

Ecologist Akhil Javad (shown) and colleagues found that tropical trees’ ability to photosynthesize may be more resilient to rising global temperatures than previously thought.Akhil Javad

In the summer, which lasts from March through June in the region, daily high temperatures in the mountains can cross 37° Celsius and are projected to rise by about 4 degrees Celsius in the next 60 years. That could be a problem for trees, since leaves can get much hotter than the surrounding air.

As the temperature of a leaf rises, its ability to harness sunlight to make sugar and oxygen becomes less efficient. On average, when leaves surpass 46.7° C, their photosynthetic machinery shuts down, lab studies have shown. When that happens, trees don’t get the energy they need. Many trees in the tropics are already experiencing temperatures beyond that average limit. More

Cloud forests are strange and ghostly places — akin to coral reefs hidden high on tropical mountains. Stunted trees loom in the mist, gnarled trunks and branches crusted in moss, lichens, orchids, ferns, bromeliads and even climbing cactus vines. Arboreal frogs and salamanders spawn in fog-fed bromeliad pools, and spider monkeys pause to sip drinks.

But these enigmatic forests are being squeezed by warming and deforestation.

Hundreds of tree and plant species that make up Mesoamerican cloud forests are being chased uphill by rising temperatures, at an average rate of 1.8 to 2.7 meters per year, researchers report in the March 7 Science. From 1979 to 2010, these forests retreated 84 meters uphill. At the same time, cattle grazing and deforestation higher on the mountains is pushing the forests downward 6.3 meters per year — squishing these ecosystems into ever narrower bands of territory. More

Rural communities in arid regions have harvested tiny droplets of fog for years as a source of fresh drinking water. Now, researchers say that fog water can be a practical supplement to stave off water stress for larger desert cities.

A yearlong assessment of the potential volume of harvested fog water near a city in northern Chile’s Atacama Desert found that it’s possible to collect as much as 5 liters per square meter each day, scientists report Feb. 20 in Frontiers in Environmental Science. More

“Dear diary, it was freezing outside today…” If someone today wrote that in their journal, it might seem like an innocuous enough line, perhaps never to be carefully considered again. But what if, 500 years from now, scientists used that entry about the weather to answer climate mysteries?

Researchers looking to the past have done just that, combing through diaries and other old documents to reconstruct the climate of 16th century Transylvania, part of modern-day Romania. What they found offers a glimpse at how a cooling period called the Little Ice Age may have affected people in the region, the team reports February 12 in Frontiers in Climate. More

Meghan Rosen is a staff writer who reports on the life sciences for Science News. She earned a Ph.D. in biochemistry and molecular biology with an emphasis in biotechnology from the University of California, Davis, and later graduated from the science communication program at UC Santa Cruz. More

Citations

H. Seroussi et al. Evolution of the Antarctic Ice Sheet over the next three centuries from an ISMIP6 model ensemble. Earth’s Future. Vol. 12, September 4, 2024. doi: 10.1029/2024EF004561.

M. Wolovick, J. Moore and B. Keefer. The potential for stabilizing Amundsen Sea glaciers via underwater curtains. PNAS Nexus. Vol. 2, April 2023, pgad103. doi: 10.1093/pnasnexus/pgad103.

B. Keefer, M. Wolovick and J.C. Moore. Feasibility of ice sheet conservation using seabed anchored curtains. PNAS Nexus. Vol. 2, March 2023, pgad053. doi: 10.1093/pnasnexus/pgad053.

K. Yamazaki et al. Multidecadal poleward shift of the southern boundary of the Antarctic Circumpolar Current off East Antarctica. Science Advances. Published online June 11, 2021. doi: 10.1126/sciadv.abf8755.

R. DeConto et al. The Paris Climate Agreement and future sea-level rise from Antarctica. Nature. Vol. 593, May 6, 2021, p.83. doi: 10.1038/s41586-021-03427-0.

A.K. Wåhlin et al. Pathways and modification of warm water flowing beneath Thwaites Ice Shelf, West Antarctica. Science Advances. Vol. 7, April 9, 2021, eabd7254. doi: 10.1126/sciadv.abd7254.

O. Gürses et al. A submarine wall protecting the Amundsen Sea intensifies melting of neighboring ice shelves. The Cryosphere. Vol. 13, September 6, 2019, p. 2317. doi: 10.5194/tc-13-2317-2019.

M.J. Wolovick and J.C. Moore. Stopping the flood: Could we use targeted geoengineering to mitigate sea level rise? The Cryosphere. Vol. 12, September 20, 2018, p. 2955. doi: 10.5194/tc-12-2955-2018.

J.C. Moore et al. Geoengineering polar glaciers to slow sea-level rise. Nature. Vol. 555, March 15, 2018, p. 303. doi: 10.1038/d41586-018-03036-4.

I. Joughin et al. Marine Ice Sheet Collapse Potentially Under Way for the Thwaites Glacier Basin, West Antarctica. Science. Vol. 344, May 16, 2014, p. 735. doi: 10.1126/science.1249055.

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On a remote island in the Canadian Arctic, researchers have discovered the remains of an ancient glacier that could be over a million years old. The discovery represents what may be the oldest glacier ice ever found buried in permafrost — ground that has been frozen for at least 2 years straight — in the Arctic, researchers report in the January 1 Geology. For researchers keen on studying the glacier, the clock is ticking, as human-caused climate change has exposed the long-preserved ice to melting.

Like notes in the pages of a logbook, the gas bubbles, compounds and particulates trapped in a glacier’s icy layers can yield information about the atmospheres and climates of bygone millennia. But there are precious few reports of such ice older than the last great expansion of the ice sheets, 26,000 to 20,000 years ago. The newfound ice could thus provide researchers with a rare chance to study the climate of the early Pleistocene epoch, during which the Earth underwent episodic ice ages separated by warm periods known as interglacial periods. “These [Pleistocene climate shifts] are analogs for what we can see in the future,” says geomorphologist Daniel Fortier of the University of Montreal.

In 2009, Fortier and colleagues were studying a buried fossilized forest on Bylot Island, in Canada’s Nunavut Territory, when they stumbled across the sites of some recent landslides that had been triggered by the thawing of permafrost. The slides had exposed translucent, layered bodies of ice that had been buried a few meters underground, just above the fossil forest. Much to Fortier’s surprise, radiocarbon dating of organic matter in the ice revealed it was over 60,000 years old. “I was not expecting that at all,” he says.

Researchers are shown digging into the remnant glacier ice, which became exposed by the thawing and slumping of previously frozen ground.Stéphanie Coulombe

What’s more, in the sediment layers overlying the ice, the researchers discovered a flip in the alignment of magnetic minerals that corresponded with a reversal of Earth’s magnetic field roughly 770,000 years old, indicating the ice was at least that old. And previous research had dated the fossil forest upon which the glacier rested to around 2.8 to 2.4 million years ago, providing a maximum possible age for the ice.

The discovery is a testament to the resilience of permafrost, Fortier says. While climate projections suggest permafrost will completely thaw in many regions by the end of the century, this preserved glacier has persisted through interglacial periods that were warmer than today, he notes. “I don’t think permafrost will disappear so fast. The system is more resilient than we think.” More

Unusually dry conditions and hurricane-force seasonal winds are fueling multiple fast-moving and destructive wildfires in Los Angeles County. Gusts that reached over 145 kilometers per hour (90 miles per hour) quickly drove the blazes into urban areas, forcing more than 100,000 people to evacuate from their homes and killing at least two people as of January 8.

The largest of the blazes, known as the Palisades fire, erupted the morning of January 7 on the west side of Los Angeles and has since burned more than 6,400 hectares (15,800 acres) and destroyed around 1,000 structures. The second largest, called the Eaton fire, ignited near Pasadena that night and had burned more than 4,290 hectares by the next morning. A third blaze, the Hurst fire near Sylmar, has burned more than 200 hectares. More