By Elizabeth Pennisi , Science.  Excerpt: Climate change  emerged as a driving factor behind urban rat swarms , the researchers report today in  Science Advances . As temperatures rise, they conclude, and people flock to urban areas and convert formerly “green” spaces into neighborhoods and shopping centers, they created a perfect storm for rat populations to explode. And the city that’s fared the worst over the past decade? Washington, D.C.....  Full article at https://www.science.org/content/article/warmer-more-crowded-cities-bring-out-rats . 

By Louise C. Archer et al, Science.  Summary: ...polar bear populations have declined over the past 50 years as the extent of sea ice has decreased. Archer  et al . used data collected from polar bears in the western Hudson Bay Area over nearly all of that time.... Energetic patterns at the individual level successfully predicted larger-scale population dynamics. A single driver, energy limitation, emerged as being responsible for the population decline, confirming that polar bears face food shortages due to the loss of ice. —Sacha Vignieri....  Full article at https://www.science.org/doi/10.1126/science.adp3752 . 

By https://www.science.org/doi/10.1126/sciadv.ads8163 et al, Science.  Abstract: Coastal vertical land motion (VLM), including uplift and subsidence, can greatly alter relative sea level projections and flood mitigations plans. Yet, current projection frameworks, such as the IPCC Sixth Assessment Report, often underestimate VLM by relying on regional linear estimates. Using high-resolution (90-meter) satellite data from 2015 to 2023, we provide local VLM estimates for California and assess their contribution to sea level rise both now and in future. Our findings reveal that regional estimates substantially understate sea level rise in parts of San Francisco and Los Angeles, projecting more than double the expected rise by 2050. Additionally, temporally variable (nonlinear) VLM, driven by factors such as hydrocarbon and groundwater extraction, can increase uncertainties in 2050 projections by up to 0.4 meters in certain areas of Los Angeles and San Diego. This study highlights the ...

By Rebecca F. Elliott , The New York Times.  Excerpt: The artificial intelligence boom has turbocharged demand for electricity, and everyone who is anyone in the U.S. energy industry wants a piece of the action. The latest entrant is Chevron, the country’s second-largest oil and gas company, which sees opportunity in building natural gas-fueled power plants that will feed energy directly to data centers....  Full article at https://www.nytimes.com/2025/01/28/business/energy-environment/chevron-power-plant-ai.html . 

By Meg Bernhard , The New York Times.  Excerpt: ...the expansion of renewable-energy infrastructure is fundamentally reshaping the landscape of the West, often at the expense of ecosystems. Lithium mining in particular alarms conservationists. Depending on the type of process used, mining can pollute groundwater, emit carbon dioxide, create toxic waste and destroy habitats. As companies scramble to acquire mineral rights, in many cases under an antiquated mining law, some conservationists are criticizing the fact that there isn’t a federal plan to protect the landscape, without which they fear a ruinous mining free-for-all. This rush to mine has put them in tension with proponents of the federal government’s green-energy projects, who warn against slowing an urgent process. Conservationists, in turn, worry that those supporters are being shortsighted in their disregard for the value of biodiversity....  Full article at https://www.nytimes.com/2025/01/24/magazine/nevada-lithium...

By A. J. R. Smith et al, Science.  Editor's summary: Shrimp-like krill constitute the greatest biomass of any living animal: up to 379 million tonnes in the Southern Ocean. Dead krill and their feces sink and are assumed to export tens of millions of tons of carbon annually; however, these data are gleaned from patchy observations. Smith  et al . deployed a seafloor lander carrying an echosounder, camera, lights, and other equipment offshore of East Antarctica to provide consistent direct observational data, including difficult-to-obtain winter data, to feed into a carbon flux model. The year-long observations showed heterogeneous migratory behaviors by krill, including strong seasonal shifts. Migration means that recirculation of carbon can occur, so krill may make a smaller contribution to net carbon storage than what is found in current estimates. —Caroline Ash.  Full article at https://www.science.org/doi/full/10.1126/science.adq5564 . 

By   Zack Budryk , The Hill.  Excerpt: Businessman and former New York Mayor  Michael Bloomberg  said this week his philanthropic foundation will contribute the U.S.’s financial obligations under the Paris Climate Agreement to the United Nations Framework Convention on Climate Change (UNFCCC) after President Trump announced he would withdraw the U.S. from the agreement. In a statement Wednesday through Bloomberg Philanthropies, Bloomberg said the organization will both cover the U.S.’s funding gap and its reporting requirements for planet-warming emissions. The announcement does not specify a dollar amount the organization will contribute, but it committed about $15 million to the UNFCCC between 2017 and 2020 after Trump announced the withdrawal of the U.S. from the agreement in his first term. The U.S. ordinarily pays about a fifth of the UNFCCC budget, which amounted to about $7.5 million in 2024. “Bloomberg Philanthropies has made significant investments in empowe...

By Zhenye Wang et al, Science.  Editor's summary: Stretchable organic solar cells for powering wearable devices have been achieved by blending a ductile donor semiconductor polymer with a plasticizing small-molecule acceptor to overcome the inherent brittleness of the photoactive components. Wang  et al . have shown that the acceptor actually enhances ductility in the blend and maintains electron mobility despite its lack of crystallinity. Devices achieved a power conversion efficiency of greater than 16% and could maintain 80% of that efficiency at 80% strain. —Phil Szuromi Full article at https://www.science.org/doi/10.1126/science.adp9709 .

By Robert F. Service, Science.  Excerpt: Hydrogen is often touted as the future of green energy, and the allure is clear. When burned or run through a fuel cell, the fuel produces water as exhaust, not carbon dioxide (CO 2 ). It is energy-rich enough to drive semitrailer trucks, cargo ships, and other heavy-duty vehicles that are tough to power with batteries. And for many industrial processes requiring high-temperature reactions, such as fertilizer production and steel manufacturing, hydrogen is basically the only alternative to fossil fuels, says Kathy Ayers, a water electrolysis expert at Nel Hydrogen, a Norwegian electrolyzer producer. “Low-carbon hydrogen is absolutely essential if we are going to address the climate crisis.” ...According to the International Energy Agency, the world needs to churn out more than 300 million tons of green hydrogen annually if it is to have a shot at limiting global warming to 1.5°C by 2050. Yet today, operating green hydrogen plants, mostly in ...

By Brad Plumer , The New York Times.  Excerpt: President Trump launched a broad attack on the wind power industry in the United States, with  a sweeping executive order  that could block not just new offshore wind farms in the Atlantic and Pacific Oceans but potentially many smaller wind farms on federal land and even on private property across the country. The order...would halt all leasing of federal lands and waters for new wind farms pending a fresh government review of the industry. It also directs federal agencies to stop issuing permits for all wind farms anywhere in the country for the time being, a move that could disrupt projects on private land, which sometimes need federal wildlife or other environmental permits. While the order does not call for a freeze on wind projects that are already under construction, Mr. Trump directed the U.S. Attorney General and secretary of the interior to explore the possibility of “terminating or amending” any leases that have al...

By Caroline Hasler , Eos/AGU.  Excerpt: With global  sea levels  projected to rise 44 centimeters (17 inches) by the end of the century, atolls such as Aldabra—a  United Nations Educational, Scientific and Cultural Organization (UNESCO) World Heritage Site  in Seychelles and home to the world’s largest population of giant tortoises—may be at risk of sinking into the ocean. A new  study , however, shows that despite consistently rising sea levels, most of Aldabra’s shoreline hasn’t changed since 1960. ...An atoll forms when corals attach to the margins of a volcanic island or platform in the ocean. Over time, the volcano is eroded and subsides into the sea, leaving a ring-shaped reef. Winds and waves deposit crushed coral from surrounding reefs on top of the ring, ultimately forming islands that rise above sea level. ...“Our research shows that Aldabra’s resilience to sea level rise is likely linked to its high protection status. This serves as a crucial les...

By Yifan Gao et al, Joule.  Paper summary: Although ammonia production is crucial for global agriculture, it comes with substantial carbon footprints. [ammonia production is the chemical industry’s biggest greenhouse gas emitter] Here, for the first time, we propose and demonstrate a different method for stimulated (proactive) and  in situ  geological ammonia (Geo-NH 3 ) production directly from rocks. Our approach demonstrated that NH 3  can be efficiently generated by reacting natural (Fe,Mg) 2 SiO 4  (olivine) minerals with nitrate-source water at 130°C–300°C and 0.25–8.5 MPa, and even at ambient temperature and pressure. Using both actual rocks and synthetic mineral Fe(OH) 2 , we investigated mechanisms and optimized conditions through experiments and theoretical calculations. We revealed the basic chemistry enabling Geo-NH 3  production: Fe 2+  contained in rocks reduces the nitrate source to NH 3 . Our approach, involving only the injection...

By EnergyNow Media.  Excerpt: Global energy storage capacity has tripled in recent years, thanks to an industry that barely existed a decade ago. ...The rapid growth of large-scale energy storage is driven by  plunging battery prices , rising  electricity demand  and a recognition among operators, utilities and public officials that  grids are less reliable  than they once were. “Energy storage has become a linchpin” for avoiding disruptions, says Joseph Williamson, vice president for projects at esVolta LP, the company that developed and owns the Hummingbird facility, which will store electricity delivered by a nearby PG&E substation. EsVolta will sell the energy back to grid customers as needed....  Full article at https://energynow.com/2025/01/giant-batteries-are-transforming-the-worlds-electrical-grids/ .  See also U.S. Power Grids are Vulnerable to Extreme Weather . 

By David L. Hoover  and  William K. Smith , Science.  Excerpt: Droughts have major societal and ecological impacts, including drinking water shortages, crop failures, tree mortality, wildfires, and reduced ecosystem productivity ( 1 ). Shifts in the hydrological cycle and continued warming with climate change are leading to rapidly evolving droughts that are more intense and longer lasting ( 2 ). Extreme but short-term droughts (<1 year) can have a wide range of consequences, depending on the severity and timing of the drought as well as an ecosystem’s resistance ( 3 ,  4 ). However, as a drought extends to a multiyear event, these ecological effects can amplify because short-lived buffering from physiological adaptations or water storage may weaken, leading to longer-lasting results ( 4 ). On page 278 of this issue, Chen  et al . ( 5 ) report that increasing precipitation anomalies and atmospheric moisture demands are leading to multiyear droughts ...

By Jesse Radolinski   et al, Science.  Summary: With climate change, droughts are expected to become more frequent and severe in many regions, but temperature and elevated CO 2  may modify its effects on soil, water, and vegetation: temperature by increasing plants’ water needs and CO 2  by decreasing them. Radolinski  et al . conducted a field experiment in an Austrian montane grassland to determine the effects of these changes on soil water. Under drought, elevated CO 2 , and warming, plants reduced transpiration, conserving water. Plants treated in this way (but not those with only one manipulated factor) used a larger proportion of recently precipitated water from large pores and with little mixing, showing that future drought will likely fundamentally change how water moves in soil. —Bianca Lopez.  Full article at https://www.science.org/doi/10.1126/science.ado0734 . 

By Meredith Wadman , Science.  Excerpt: ...The disease [ Coccidioides fungus] causes ...Valley fever is familiar in the Southwest, where it has infected wildland firefighters; carrot, beet, and radish pickers; solar power farm builders; and cast and crew members on a Ventura County film set. ...the fungal spores, nourished in the warm, wet confines of the lung, morph into structures called spherules that burst to release boatloads of tiny endospores that become new spherules, continuing the cycle. Most of these people have a flulike illness lasting weeks or months. But 5% to 10% of cases result in lifelong lung infections, sometimes forcing people to be on powerful antifungal medications permanently. ...cases are escalating fast. Diagnoses ...have ballooned from  about 2800 annually  at the turn of the century to  about 20,000 in 2023 , with at least 200 people dying each year. Arizona and California, where roughly 97% of U.S. cases are reported, have seen dram...

By Connor Letourneau , San Francisco Chronicle.  Excerpt: “When people fight the ocean,” [Pacifica, City Council member Christine] Boles said, “the ocean always wins.” ...Pacifica, a picturesque surf town of roughly 35,000 just south of San Francisco, has become an important case study for the increasingly urgent questions  climate change  raises for many coastal communities. Should residents stay to defend their homes from rising tides that grow fiercer by the year? Or, should they admit defeat and cede the land back to nature? ...“Managed retreat” — a term coined by geologists to describe the process of removing people, homes and businesses from at-risk areas — is at the root of the debate. ...“We can’t build seawalls high enough to protect us forever,” said Gary Griggs, a professor of Earth and planetary sciences at UC Santa Cruz. “So, in the long run, it’s either going to be managed retreat or unmanaged retreat. It’s up to each community to decide.”...  Full...

By Kimberly M. S. Cartier , Eos/AGU.  Excerpt: More than 3 billion people experienced their hottest year ever in 2024 because of anthropogenic climate change. The world is speeding toward its 1.5°C warming target. ...“Even if we likely exceeded [1.5°C] this year, that doesn’t mean that we’ve exceeded it in the context of the Paris accord, which is over a longer time period,” Schmidt said. “But I will say that we anticipate future global warming as long as we are emitting greenhouse gases, and until we get to net zero, we will not get a leveling off of global mean temperature.”....  Full article at https://eos.org/articles/exceptional-global-warming-spike-continued-in-2024 . 

By Laura Paddison , CNN.  Excerpt: It’s official: 2024 was the hottest year on record, breaking the  previous record  set in 2023 and pushing the world over a critical climate threshold, according to new data from Europe’s climate monitoring agency Copernicus [ https://climate.copernicus.eu/copernicus-2024-first-year-exceed-15degc-above-pre-industrial-level ]. Last year was 1.6 degrees hotter than the period before humans began burning large amounts of fossil fuels, Copernicus found. It makes 2024 the first calendar year to breach  the 1.5-degree limit  countries agreed to avoid under the Paris climate agreement in 2015. Scientists are much more concerned about breaches over decades, rather than single years — as above that threshold humans and ecosystems may struggle to adapt — but 2024’s   record   “does mean we’re getting dangerously close,” said Joeri Rogelj, a climate professor at Imperial College London....  Full article at https://www.cnn.c...

By Valério D. Pillar  and  Gerhard E. Overbeck , Science.  Excerpt: Over half of Earth’s land surface is covered with  fire-prone vegetation , with grassy ecosystems—such as grasslands, savannas, woodlands, and shrublands—being the most  extensive . In the context of the climate crisis, scientists worldwide are exploring  adaptation  measures to address the heightened fire risk driven by more frequent extreme climatic conditions such as droughts and heatwaves, as well as by  non-native plant invasions  that increased fuel loads and altered fire regimes. Although fire is intrinsic to  grassy ecosystems , rising exposure to wildfire smoke harms human health and the environment. Here, we argue that grazing management in grassy ecosystems could help reduce wildfire risk and its consequences....  Full article at https://www.science.org/doi/10.1126/science.adu7471 . 

By Christopher Bataille , Science.  Excerpt: According to current climate science, global temperatures will continue to rise until net carbon dioxide (CO 2 ) emissions reach zero ( 1 )—that is, when the amount of CO 2  added to the atmosphere is balanced by the amount removed. Given current projected emissions, 2 billion to 15 billion tonnes (Gt) of CO 2  may need to be removed from the atmosphere annually to meet the goal of the 2015 Paris Agreement to limit global warming below 2°C and preferably to 1.5°C above preindustrial temperatures ( 2 ,  3 ). ...Van Roijen  et al.  ( 4 ) report that replacing traditional building materials with CO 2 -storing alternatives could sequester carbon at the billion-tonne level. ...Building materials such as asphalt, wood, stone, steel, and concrete are foundational to human civilization and have large global demands, ...~30 Gt of concrete are used each year in the world ( 5 ). Some of these materials are also major c...

By Sarah Stanley , Eos/AGU.  Excerpt: The vast  Antarctic Ice Sheet  holds  more than half  of Earth’s freshwater. In several places around the continent, the ice extends over the ocean, where it forms large floating shelves. Observations suggest many of these  ice shelves are thinning  as they melt from below, with implications for ocean dynamics, global sea level, and Earth’s climate. For now, the  Filchner-Ronne Ice Shelf —one of Antarctica’s biggest, extending over the Weddell Sea—appears to be relatively stable, thanks to near-freezing currents circulating over the continental shelf beneath it. However, climate models predict that shifting ocean currents may bring warmer water to the continental shelf in the future. To gain a clearer picture of the Filchner-Ronne Ice Shelf’s future,  Steiger et al.  analyzed water temperature and velocity data from 2017 to 2021. ...In this study, researchers found that the summertime flow of warm wa...

By Nathaniel Scharping , Eos/AGU. Excerpt: In a string of ever-hotter years, 2023 stood out: It was the  warmest on record  (though  2024 will likely surpass it ), with temperatures 1.4°C (2.5°F) above the preindustrial average and 0.17°C (0.3°F) above the previous record set in 2016. One cause for the spike may have been that Earth was just a little darker than it’s been in recent history.  Earth’s albedo , a measure of how reflective the surface is, hit a record low in 2023, according to the authors of a  study in  Science . That record was due mainly to a dearth of bright, low-level clouds, which reflect more solar radiation than land or ocean. The answers to why these clouds were absent and, crucially, whether the trend will continue are still unclear....  Full article at https://eos.org/articles/darker-less-cloudy-earth-contributed-to-record-heat .

By   Caroline Van Hemert , bioGraphic.  Excerpt: ...Peregrine falcons hold near-mythical appeal in our collective imagination, and for good reason. Topping out at speeds of more than 320 kilometers (200 miles) per hour, they’re the fastest species on Earth, plummeting from the sky like amber-eyed missiles. ...Perhaps more cosmopolitan than any other wild bird species, peregrine falcons live on every continent except Antarctica, in habitats ranging from polar deserts to subtropical rainforests. They’re flexible in what they eat—from songbirds to seabirds, carrion to chickens—and in where they nest—on cliffs, in trees, on the ground, or on buildings. Some individuals barely budge throughout their lifetimes, whereas others, like the Greenlandic variety, embody the roots of their scientific name— Falco peregrinus , or “wandering falcon”—making migrations upwards of 25,000 kilometers per year. ...Since birds like peregrines feed high on the food chain, contaminants accumulate ...

By DW.  Excerpt: Europe's largest economy saw a rise in renewable energy generation in 2024. Germany  made a notable shift toward  renewable energy  sources last year, according to a  report from the Federal Network Agency  released on Friday. Renewable energy accounted for 59% of the country's total electricity generation, up from 56% in 2023. Wind energy was the leading source, contributing 31.9% to the nation's energy mix, while solar energy contributed 14.7%. ...Last year also marked Germany's first full year  without nuclear power , following the final shutdown of its nuclear plants in April 2023. The country aims to be climate-neutral by 2045....  Full article at https://www.dw.com/en/wind-and-solar-power-drive-germanys-renewable-energy-surge/a-71213890 . 

By Madeline Reinsel , Eos/AGU.  Excerpt: A slow climate feedback loop may be bubbling beneath Antarctica’s vast ice sheet. The continent...includes volcanic giants such as  Mount Erebus and its iconic lava lake . But at least 100 less conspicuous volcanoes dot Antarctica, with many clustered along its western coast. Some of those volcanoes peak above the surface, but others sit several kilometers beneath the Antarctic Ice Sheet. Climate change is causing the ice sheet to melt, raising global sea levels. The melting is also removing the weight over the rocks below, with more local consequences. Ice sheet melt has been shown to  increase volcanic activity in subglacial volcanoes  elsewhere on the globe.  Coonin et al.  ran 4,000 computer simulations to study how ice sheet loss affects Antarctica’s buried volcanoes, and they found that gradual melt could increase the number and size of subglacial eruptions. The reason is that this unloading of ice sheets reduc...

By Andrew J. Wight , Eos/AGU.  Excerpt: In the past 70 years, more than 75,000 tornadoes have been recorded in the United States. Recordkeeping of these phenomena outside this region has been largely fragmented, sitting isolated in books, government databases, and research archives. But a new effort to scour as many publicly accessible records as possible is highlighting the scale of this hazard around the world. In a  new study ,  Malcolm Maas , an undergraduate student at the University of Maryland, College Park, and a team of tornado researchers compiled a tornado database that they hope will boost tornado research globally. ...The United States accounts for 21,548 of the recorded fatalities in the database published by Maas and his collaborators. But tornadoes in other countries wreak havoc as well: Bangladesh accounts for 8,325 fatalities in the database, India has seen 1,473, and the rest of the world combined accounts for 3,824....  Full article at https://eos...

By Neal E. Boudette , The New York Times.  Excerpt: General Motors was the biggest winner in U.S. sales in the final quarter, with a gain of 21 percent. It more than doubled its electric vehicle sales. ... Ford Motor sold more than 530,000 vehicles  in the quarter, a gain of nearly 9 percent. Ford’s E.V. sales climbed 16 percent, to more than 30,000 vehicles. ...Analysts said the year-end jump in E.V. sales might also have been spurred somewhat by President-elect Donald J. Trump, who has suggested he will eliminate the $7,500 federal tax credit on electric vehicles priced under $80,000. The tax credit has helped manufacturers offer the attractive lease deals....  Full article at https://www.nytimes.com/2025/01/03/business/ford-gm-vehicle-sales.html . 

By Jeffrey Mervis , Science.  Excerpt: John Deutch ...joined President Jimmy Carter’s energy team shortly after the Georgia Democrat took office in January 1977. And for the next 3 years Deutch had a front-row seat to history as Carter, who died on 29 December 2024 at age 100, worked to make the country less dependent on imported oil and in the process reshaped the direction of federal energy research. ...Within 6 months Deutch would become the founding director of the Office of Energy Research at the newly created Department of Energy (DOE), the successor to the Atomic Energy Commission (AEC) and the short-lived Energy Research and Development Administration (ERDA). ...Meeting DOE’s mandate also meant launching programs outside the legacy energy sources, notably fossil fuels and nuclear power, that had been the mainstay of DOE research under its predecessor agencies. ...Although the Carter administration tried hard to get people in the U.S. to conserve energy and to find alte...

By Jianbang Gan , Science.  Excerpt: Wildfire occurrence and scale worldwide have risen over recent decades, with the most destructive wildfires in North America taking place in the past decade ( 1 ,  2 ). ...On page 91 of this issue, Wang  et al . ( 3 ) report the key drivers of burn severity.... ...These studies led to the development of predictive models that are used to project wildfire effects under different scenarios over time in locations where no historical fires have been recorded. However, the drivers of wildfire effects are complex and involve multiple interlinked factors, such as climate, vegetation, topography, and human activity. ...Among all the factors, fuel aridity, which reflects the abundance and moisture content of flammable vegetative fuels, was determined to be the primary driver for most Canadian forest fires between 1981 and 2020. ...Wang  et al . found a large increase in burn severity in northern Canada compared with other regions in C...

By  Dan Charles , Science.  Excerpt: ...“This is a worldwide phenomenon,” says Peter Verburg, a land use researcher at the Free University Amsterdam. Global trade in food has fueled the clearing of forests in Brazil and Bolivia for agriculture, but elsewhere it has sidelined small farms with rocky soil, steep hills, or scarce water. “People give up because they cannot compete,” Verburg says. ...Farmers, or their children, are walking away from land in Eastern Europe, southern France, South Korea, Japan, and mountainous parts of India. It’s difficult to measure the exact extent of the trend. Land is often abandoned, then reclaimed and farmed again. But an estimated  120 million hectares  have been left fallow in Europe alone since 1990. Globally,  the figure since 1950  could be as high as 400 million hectares—half the area of Australia. “Abandonment will continue, I think there’s no doubt,” Verburg says. In fact, climate change is likely to accelerate it as...

By Chase DiFeliciantonio , San Francisco Chronicle.  Excerpt: When the California Public Utilities Commission slashed the price PG&E had to pay to buy electricity from solar customers, the industry nearly collapsed. But experts say the goal was equity — and a sustainable model that encouraged installing batteries to store power locally. ...In late 2022, [California] state regulators voted to  slash the level of that payment  by around 75% to bring it closer to market prices. ...“We were on a completely unsustainable path,” said  UC Berkeley  energy economist Severin Borenstein. “Households producing solar were compensated at the full retail price — at least double the market value of the electricity — for the quantities they sold back to the grid.” That money had to come from somewhere, and the result was that customers in PG&E’s service area who did not have solar panels were effectively subsidizing those that did, according to Borenstein...

By Dennis M. Hogan, Guest Essay for The New York Times.  Excerpt: In 2023, ...July, the middle of Panama’s rainy season. But the rains had been sparse, and water levels in the canal had sunk to troubling lows. Without freshwater from rain, our guide explained, the locks on the canal could not operate. ...the true threat to U.S. commerce through Panama. If the goal is securing affordable access to the transit point over the long term, it is climate change, not Chinese influence, that U.S. policymakers should worry about. ...Sending a single ship through the canal’s locks can use around 50 million gallons of water, mainly freshwater collected from Lake Gatún. Though the canal is, for the moment, operating at full capacity, a drier climate and greater demand for drinking water have in recent years reduced the volume of available water. That has  forced the state-run Panama Canal Authority  at times to limit the number of daily passages through the canal, at one point by as m...