Warming will leave drought-hit California reeling

Warming will leave drought-hit California reeling

Researchers in the US warn that climate change could worsen California droughts by drastically reducing water flow from the Sierra Nevada mountains − and also threatens the extinction of a rare species of fish.

LONDON, 16 September, 2014 − Things could soon get worse for drought-hit California. New research predicts that, by the close of the century, global warming could have reduced the flow of water from the Sierra Nevada mountains by at least a quarter.

Michael Goulden, associate professor of earth system science at the University of California Irvine, and Roger Bales, director of the Sierra Nevada Research Institute at the University of California Merced, publish their alarming findings in the Proceedings of the National Academy of Sciences.

Plant growth

Their research looked not at the long-term projections for precipitation in the US south-west, but simply at the effect of higher average temperatures on plant growth.

Mountains in many ways mimic hemispheres: just as trees become more stunted at higher latitudes, so they get smaller and less frequent at higher altitudes. Temperature ultimately controls plant growth.

But a projected warming of 4.1°C by 2100 would make a big difference to plant growth in the Arctic tundra and around the present alpine treeline everywhere in the world.

The scientists contemplated snow and rain conditions in the King’s River Basin in the Sierra Nevada range. They looked at how much flows downstream to local communities, and how much goes back into the atmosphere as water vapour. Then they did their sums.

They calculated that the 4.1°C temperature rise in the region would increase the density of vegetation at high elevations, with a 28% increase in evapotranspiration − the process that draws water up through the roots to the leaves, and then releases it as vapour through the pores. And what was true for one river basin, they thought, should be true for the whole area. River run-off could drop by 26%.

“Scientists have recognised for a while that something like this was possible, but no one has been able to quantify whether it could be a big effect,” said Professor Goulden. “It’s clear that this could be a big effect of climate warming and that managers need to recognise and plan for the possibility of increased water losses from forest evaporation.”

Endangered fish

MEANWHILE, climate change threatens to wipe out an endangered species of fish in a remote area of Nevada.

The Devils Hole pupfish (Cyprinodon diabolis) is not just rare, it is very rare: the population has fallen as low as 35 individuals. It lives in the geothermally-warmed waters of a limestone cavern in the Devils Hole in the Mojave desert, and its existence was probably always precarious. The fish are little more than 2cms long, iridescent blue, and they have made their home in the upper 25 metres of the cavern’s waters for at least 10,000 years.

Devils Hole pupfish are only 2cms long Image: Nevada Fish & Wildlife Office

Devils Hole pupfish are only 2cms long
Image: Nevada Fish & Wildlife Office via Wikimedia Commons

But Mark Hausner, a hydrogeologist at the Desert Research Institute in Las Vegas, Nevada, and colleagues report in the journal Water Resources Research that there is only a 10-week window in which the water temperatures are optimal, and there is enough food available, for new larvae to hatch.

Climate change is bringing the already-warm water to dangerous temperature levels, and this has already shortened by at least one week the brief opportunity to restore the population. When counts began in 1972, there were more than 500 of the fish. A decade ago there were 171, and at the last count there were only 92.

“This is a fish that does live in a fishbowl, an incredibly hostile fishbowl, and you can’t move the fishbowl,” said one of the report’s authors, Scott Tyler, professor in the Department of Geological Sciences and Engineering at the University of Nevada, Reno. “This is a species that can’t adapt or change or leave to go to a better environment.” − Climate News Network

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Human factor speeds up glacial melting

Human factor speeds up glacial melting

Scientists simulating changes in mountain glaciers over the last century and a half have established that rates of melting have increased greatly in recent years – and that humans are the main culprits.

LONDON, 17 August, 2014 – The impact of human activity is melting the glaciers in the world’s mountain regions, and is doing so at an accelerating rate.

Ben Marzeion, a climate scientist at the University of Innsbruck’s Institute of Meteorology and Geophysics, Austria, reports with colleagues in the journal Science that they used computer models to simulate changes in the world’s slow-flowing frozen rivers between the years 1851 and 2010. The study embraced all the world’s glaciers except those in Antarctica.

This kind of manipulation allows researchers to play with the possibilities and see, for instance, how much changes in the sunlight patterns, high-level atmospheric changes because of volcanic eruptions, or simply slow cycles of natural weather patterns might be at work in the ice record.

The answers were unequivocal about human impact on the environment. “In our data, we find unambiguous evidence of anthropogenic contribution to glacier mass loss,” Dr Marzeion says.

In retreat

That glaciers are losing mass − retreating uphill, and melting at a faster rate − is not in doubt. A year ago, one group established without any doubt that worldwide, and overall, glaciers are in retreat.

In South America, some glaciers in the Andes are melting at a record rate, while satellite measurements show that the Jakobshavn glacier in Greenland doubled its flow speed between 1997 and 2003, and has doubled it again since 2003.

In Europe, 19th-century landscape painters, pioneer photographers and mountain guides unwittingly made permanent, easily-accessible records of Alpine glacier geography. These now set a baseline for all modern measurements, and researchers have established that the melt is getting faster.

The challenge is to determine how much of this is due to natural causes, and how much to changes in human land use, and the emission of greenhouse gases.

Higher proportion

The Innsbruck team has calculated that around a quarter of all the melting between 1851 and 2010 can be put down to human activity. But that is the overall picture: the proportion gets higher with time. Between 1991 and 2010, the fraction of melting due to human activity rose to two-thirds.

“In the 19th century and first half of the 20th century we observed that glacier mass loss attributable to human activity is barely noticeable, but since then has steadily increased,” Dr Marzeion says. – Climate News Network

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Potatoes pioneer crops swap trail

Potatoes pioneer crops swap trail

Small-scale farmers from as far apart as Peru, China and Bhutan have agreed to share indigenous crop varieties in a pioneering initiative to help adaptation to climate change.

LONDON, 21 May − A warming climate may confront any of us with unfamiliar problems. The upside, though, is that people half a world away from each other may already have some answers.

Small-scale farmers on two continents – from Yunnan in China and from Bhutan and Peru − are now working together to help their communities to adapt to the impacts of a hotter world.

They have agreed to share indigenous crop varieties, and the knowledge needed to grow them in different climates and landscapes, in a scheme that aims to maintain resilient food systems relying on a number of crops, not simply monocultures.

The aim is also to provide the farmers with secure access to seeds each season, and to protect “food sovereignty”, so that they retain control of their harvests without agribusiness intervening.

Food security

The agreement was reached in late April at a meeting in the Potato Park, near the high-altitude Peruvian city of Cusco. The Park conserves 1,460 different potato varieties to protect food security in the face of climate change.

For the moment, the agreement involves only potatoes, although other species may be included later. The tubers themselves will not be swapped, but only in vitro material   –  with scientists from Peru‘s International Potato Center (CIP) in Lima alert to preventing any unwitting transfer of parasites or diseases.

“This partnership represents a unique alliance forged by indigenous peoples to overcome the threats to agriculture and food security in a changing climate,” said Alejandro Argumedo, the director of not-for-profit Asociación ANDES, one of the scheme’s organisers.

He told the Climate News Network that there was no comparable scheme “with this particular focus on climate change adaptation and biocultural heritage innovation as key to resilience”.

“Although our communities are half a world apart,
they share similar concerns.”

Yiching Song, from the Center for Chinese Agricultural Policy of the Chinese Academy of Sciences, said: “Although our communities are half a world apart, they share similar concerns. Communities are stronger working together than apart.”

The head of CIP’s Gene Bank, David Ellis, said: “Achieving sustainable food security in a world with a growing population, changing diets and a changing climate is a major challenge. Alliances among farming communities and scientists, such as this one, are a critical element in the response to these challenges.”

Planting line

Farming communities in all three countries are already being affected by climate change, the scheme’s organisers say. They are experiencing higher temperatures, leading to more pests and reduced water availability. For example, in the Potato Park, high in the Peruvian Andes, glaciers are melting, and the top of the planting line has been reached, so farmers are having to find new areas to plant the potatoes.

Krystyna Swiderska, an agro-ecologist at the London-based International Institute for Environment and Development, which helped to fund the farmers’ meeting, told the Network that the agreement was concentrating on species that would grow well in mountain conditions.

She said: “The focus will be on crops that perform well in harsh environments prone to droughts, frost, flooding, pests and so on, and on increasing diversity. The greater the diversity of crops th at communities have, the greater the chances of growing food in the face of increasingly extreme weather.”

Swiderska said Peru, Bhutan and China shared similar basic cultural values and traditional farming systems. The three countries also had been involved because they are participating in the Mountain Communities Initiative (MCI) meeting in Bhutan on climate change impacts, in the last week of May.

She believes that the Cusco agreement could work elsewhere. “The transfer of knowledge will be replicated at the MCI, which will involve 14 communities from 10 countries,” she said. “The transfer of seeds has not happened yet, but could potentially be replicated in other communities participating in the MCI and beyond.” − Climate News Network

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Rockies flora show climate impact

Rockies flora show climate impact

An intensive study of the flora of one meadow in the Rocky Mountains of Colorado over nearly 40 years reveals a widespread and consistent pattern of climate-induced change.

LONDON, 19 March – Two thirds of alpine flowers have changed their pattern of bloom in response to climate change. Half of them have begun to bloom weeks earlier than normal, one third are reaching their peak bloom well ahead of the traditional almanac date, and others are producing their last blooms later in the year.

The season of flowers – that feast for bees and butterflies, and a signal for insectivorous birds to make the most of their moment in the sun – is a month longer than it was four decades ago.

This conclusion comes with two qualifications. The first is that it is limited to one meadow in one location in Colorado’s Rocky Mountains in the US. But the other is that it is the product of a meticulous, painstaking 39-year-long study by one researcher. So it follows that since there is not much room for mistake or argument about the pattern in one well-studied location, then a similar pattern probably does apply in many upland temperate zone sites.

When David Inouye of the University of Maryland began his research, he was a graduate student who just wanted to know what sources of nectar were available for hummingbirds and bumble bees. So he started counting flowers about 3,000 metres above sea level in Crested Butte, Colorado, at the Rocky Mountain Biological Laboratory. And he carried on.

Big picture

He and colleagues report in the Proceedings of the National Academy of Sciences that they chose 60 common wildflower species – most of them perennial herbs – and they specifically excluded the rarer species because there was not enough data. So they made their judgement on the basis of two million flower counts, during the 39-year interval in which summer air temperatures increased by about 0.4°C per decade and in which the spring snow melt advanced by about 3.5 days per decade.

And they also specifically looked at the entire pattern of spring and summer bloom: the big picture of what biologists call phenology, the timing of biological events, in one place.

“Most studies rely on first dates like flowering or migration, because they use historical data sets that were not intended as scientific studies”, said Professor Inouye. “First flowering is easy to observe. You don’t have to take the time to count the flowers. So that’s often the only information available. It has taken a lot of effort to get the comprehensive insights needed for this analysis which helps us understand how ecological communities are going to change in the future.”

Biologists around the world have begun to use phenological shifts as indicators of climate, and as a basis for future conservation plans, and all of them have observed a pattern of change.

Consistent findings

European researchers confirmed that plants were either moving to higher latitudes, or blooming earlier in response to global warming, and that birds, butterflies and blossoms were actually heading to higher altitudes. Some have used historic observations by one of America’s literary giants as the basis for their research into climate change, and others have looked at the consequences of changes in the plant timetable for the grazers and predators that depend on specific plant communities.

But Inouye and colleagues now think that much of the phenological evidence so far has underestimated the numbers of species that have altered their flowering times, and probably overestimated the magnitude of change: what matters in the field or the meadow is the sum of all the changes, and not just the first dates of flowering.

Inouye and students divided the meadow into 30 plots, and counted flowers every other day for 39 years, for five months every year. So because of the initial basis of the research, continued for so many years, the scientists had sure data on changes for individual species, including the first flowering, the peak flowering and the last blooms, along with a measure of changes in abundance.

The date of first flowering has advanced by six days per decade, the spring peak is on average five days earlier per decade, and the last flower of autumn has been three days later every decade. – Climate News Network

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Malarial mosquitoes flying higher

Malarial mosquitoes flying higher

Scientists are finding that malaria carrying mosquitoes can survive in higher regions in warmer periods. With changes in climate that’s bad news. 

LONDON, 15 March – Things are looking up for the little parasite that infects 200 million people a year, and kills more than 600,000 of them.

As global temperatures rise, so will the altitude at which the Anopheles mosquito and its plasmodium parasite can survive, and so will the numbers at risk from malaria.

The global war against malaria has always been an uphill struggle, but populations in highland regions have usually been safe, because the parasite cannot replicate at low temperatures.

Disease spread

But Amir Siraj of the University of Denver in Colorado in the US and colleagues in the UK and Ethiopia report in the journal Science that they’ve started to consider the effect of climate change on the spread of the disease.

Projections of hazards such as these are difficult: the likelihood of infection can depend on steps civil, national and international health authorities may take, the preparedness of communities depends on spraying programmes and the availability of drugs, and the numbers at risk alter as populations grow and economies develop.

All malaria needs is somewhere warm and wet, and a steady supply of potential hosts. The disease was once endemic in mild, low-lying or marshy areas of Europe (the name comes from the Italian mal aria, or bad air).

It can be controlled by spraying, and by public education. But it remains an enduring hazard in Africa, parts of Asia and South America. Upland communities, however, have tended to be safe.

Data search

But the Denver team decided to forget about all the complex possibilities and just look at some very precise data from 124 municipalities in Antioquia in western Colombia between 1990 and 2005, and 159 administrative units in the Debre Zeit region of Ethiopia from 1993 to 2005.

They reasoned that a match of seasonal temperatures and reported cases would tell them what to expect.

Sure enough, they found that during warmer years, there were more reported cases of malaria in both countries. The “median altitude” at which cases were registered shifted accordingly with annual temperatures. That gave them enough information to consider some alarming possibilities.

In a previous study, scientists predicted that a 1°C rise in global average temperatures could bring an additional three million cases a year in Ethiopia among children under 15. As average temperatures rise, so will the numbers of potential victims soar, and so will the need for investment in mitigation and insect control.

“With progressive global warming, malaria will creep up the mountains and spread to new high altitude areas,” said Menno Bouma of the London School of Hygiene and Tropical Medicine, one of the authors.

“And because these populations lack protective immunity, they will be particularly vulnerable.”- Climate News Network



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India’s diesel fumes fuel glacier melt

India’s diesel fumes fuel glacier melt

As India’s economy expands, so does pollution, particularly in the country’s major cities. Kieran Cooke, one of our editors, has recently been in Kolkata, one of the country’s biggest and most polluted population centres: he says increasing pollution is not only harming Kolkata’s citizens – it’s also a likely contributor to climate change taking place in the Himalayan region.

KOLKATA, 6 March – Being a traffic policeman in Kolkata is a life-threatening business. Not only are you at risk of being run over on the traffic-clogged roads and streets of this chaotic city of 14 million – you’re also more than likely to suffer from serious health problems due to some of the worst air pollution not just in India, but in the world.

According to a 2012 report by the New Delhi-based Centre for Science and Environment on air quality in Kolkata, seven out of every ten people in the city suffer from some form of respiratory ailment: not surprisingly, traffic policemen and the city’s thousands of street dwellers are among the high risk groups.

Air pollution, particularly related to diesel-fuelled vehicles that jam Kolkata’s roads, is also linked to the city’s unusually high levels of lung cancer.

Meanwhile the government’s own Central Pollution Control Board gives Kolkata and New Delhi the unenviable status of being joint winners of India’s most polluted city prize.

All this is not just bad news for people living in Kolkata and India’s other major urban conglomerations. The increasing air pollution in India’s cities – particularly those in the northern parts of the country – also has an impact on the degree of melt taking place in glaciers in the Himalayas.

Soaking up the heat

Diesel fumes, along with smoke from coal burning, cooking fires and the burning of waste, are among the main sources of particulate matter called soot or black carbon. Recent studies suggest that funeral pyres and even the burning of incense at temples are also contributors to the accumulation of soot.

This black carbon rises into the atmosphere and is driven by winds on to the snow or ice in the Himalayas, darkening the surface and in the process reducing reflectivity and causing the surface to absorb more heat.

The International Centre for Integrated Mountain Development (ICIMOD), based In Kathmandu, Nepal, is the only transboundary organisation looking at climate developments across the Hindu Kush-Himalayan region.

According to ICIMOD estimates, black carbon is likely responsible for a large part – around 30% by some calculations – of glacial melt in the region. It says most of the black carbon deposited in the Himalayas and in the southern area of the Tibetan Plateau comes from the plains of India, while black carbon on the eastern and northern parts of the Plateau originates in central China.

Bigger harvests

ICIMOD says that while data is limited, studies suggest black carbon may not only be a factor in hastening the melt of mountain glaciers – it could also substantially alter rainfall patters and affect the behaviour of the monsoon.

While many well-organised environmental NGOs and other groups have formed in India in recent years, the environment – and climate change – does not come high on the political agenda.

A late 2013 study by the World Bank and the International Cryosphere Climate Initiative (ICCI) said that up to a million deaths could be avoided each year in the Himalayan region by cutting back on emissions of black carbon and methane. The study also said that regional yields of crops such as rice and wheat could be significantly improved by reducing black carbon.

“The health of people around the world will improve greatly if we reduce emissions of black carbon and methane”, says Jim Yong Kim, the World Bank president.

“Limiting these emissions will also be an important contributor to the fight against climate change.” – Climate News Network

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Tree roots ‘are natural thermostat’

Tree roots 'are natural thermostat'

Trees can influence the climate in unexpected ways, and British researchers say their roots are an important way of helping rocks to weather and drawing carbon dioxide from the atmosphere.

LONDON, 18 February – Trees have become a source of continuous surprise. Only weeks after researchers demonstrated that old forest giants actually accumulate more carbon than younger, fast-growing trees, British scientists have discovered that the great arbiters of long-term global temperatures may not be the leaves of an oak, a pine or a eucalypt, but the roots.

The argument, put by a team from Oxford and Sheffield Universities in the journal Geophysical Research Letters, begins with temperature. Warmer climates mean more vigorous tree growth and more leaf litter, and more organic content in the soil. So the tree’s roots grow more vigorously, say Christopher Doughty of Oxford and colleagues.

They get into the bedrock, and break up it up into its constituent minerals. Once that happens, the rock starts to weather, combining with carbon dioxide. This weathering draws carbon dioxide out of the atmosphere, and in the process cools the planet down a little. So mountain ecosystems – mountain forests are usually wet, and on conspicuous layers of rock – are in effect part of the global thermostat, preventing catastrophic overheating.

The tree is more than just a sink for carbon, it is an agency for chemical weathering that removes carbon from the air and locks it up in carbonate rock.

That mountain weathering and forest growth are part of the climate system has never been in much doubt: the questions have always been about how big a forest’s role might be, and how to calculate its contribution.

Keeping climate stable

US scientists recently studied the rainy slopes of New Zealand’s Southern Alps to begin to put a value on mountain ecosystem processes. Dr Doughty and his colleagues measured tree roots at varying altitudes in the tropical rain forests of Peru, from the Amazon lowlands to 3,000 metres of altitude in the higher Andes.

They measured the growth to 30 cms below the surface every three months and did so for a period of years. They recorded the thickness of the soil’s organic layer, and they matched their observations with local temperatures, and began to calculate the rate at which tree roots might turn Andean granite into soil.

Then they scaled up the process, and extended it through long periods of time. Their conclusion: that forests served to moderate temperatures in a much hotter world 65 million years ago.

“This is a simple process driven by tree root growth and the decomposition of organic material. Yet it may contribute to the Earth’s long-term climate stability. It seems to act like a thermostat, drawing more carbon dioxide out of the atmosphere when it is warm and less when it is cooler”, Dr Doughty said.

If forests cool the Earth, however, they might also warm it up. A team from Yale University in the US has reported in Geophysical Research Letters that forest fires might have had an even greater impact on global warming during the Pliocene epoch about three million years ago than carbon dioxide.

Rapid rise expected

Nadine Unger, an atmospheric chemist, and a colleague have calculated that the release of volatile organic compounds, ozone and other products from blazing trees could have altered the planet’s radiation balance, by dumping enough aerosols into the atmosphere to outperform carbon dioxide as a planet-warmer.

In fact, the Pliocene was at least 2°C or 3°C warmer than the pre-industrial world. The Pliocene is of intense interest to climate scientists: they expect planetary temperatures to return to Pliocene levels before the end of the century, precisely because humans have cleared and burned the forests, and pumped colossal quantities of carbon dioxide into the atmosphere. The greater puzzle is why a rainy, forested and conspicuously human-free world should have been so much warmer.

“This discovery is important for better understanding climate change through Earth’s history, and has enormous implications for the impacts of deforestation and the role of forests in climate protection strategies”, Dr Unger said.

All this scholarship is concerned with the natural machinery of ancient climate change, and the Yale research was based on powerful computer simulations of long-vanished conditions that could not be replicated in a laboratory.

Meanwhile, ironically, forest scientists have had a chance to test the levels of volatile organic discharges from blazing forests because freakish weather conditions in Norway have seen unexpected wild fires in tracts of mountain forest. December was one of Norway’s warmest winter months ever. In one blaze, 430 residents were forced to evacuate. – Climate News Network

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Rainy mountains speed CO2 removal

Rainy mountains speed CO2 removal

The speed at which soil is produced by rain falling on mountain slopes proves to be much faster than science had realised – with significant implications for carbon in the atmosphere.  

LONDON, 19 January – US scientists have measured the rate at which mountains make the raw material for molehills – and found that if the climate is rainy enough, soil gets made at an astonishing speed. And in the course of this natural conversion of rock to fertile farmland and forest loam, carbon is naturally removed from the atmosphere.

Isaac Larsen of the University of Washington in Seattle and colleagues from California and New Zealand took a closer look at rates of weathering on the western slopes of the Southern Alps in New Zealand. They report in Science that, according to their measurements, rock is being transformed into soil more than twice as fast as previously believed.

On the ridge tops of the NZ mountains, soil was being manufactured by chemical weathering (which is scientific shorthand for rain splashing on rock) at the rate of up to 2.5mm a year.

“A couple of millimeters a year sounds pretty slow to anyone but a geologist”, said David Montgomery, one of the authors. “Isaac measured two millimeters of soil production a year, so it would take just a dozen years to make an inch of soil. That’s shockingly fast for a geologist, because the conventional wisdom is it takes centuries.”

The research matters because – once again – it throws new light on one of the dark regions of the climate machine: how carbon dioxide is removed from the atmosphere, at what rate, and where it goes and where it all ends up.

Temperature drop

The Southern Alps of New Zealand are in geological terms young, and still going up in the world: they include some of the fastest-uplifting mountains on the planet. They are also among the rainiest: more than 10 metres of precipitation a year, on average.

Uplift – the process of mountain-building – provides fresh new rock for weathering to work on. Rainclouds arrive on the prevailing winds from the Tasman Sea, hit the mountain sides, rise, condense and release their burden on the western slopes, to generate colossal run-off, lots of silt and rock fragments and dissolved silica, and to nourish dense, vigorous forests at the bottom of the slope.

And along with all this trickling water and new soil is a steady delivery of carbon, removed from the atmosphere’s carbon dioxide.

The hypothesis that mountains play a role in chemical weathering, carbon dioxide removal and climate change is not new. Decades ago scientists argued that when the continent of India slammed into Asia and lifted up the Himalayas and the Tibetan plateau more than 50 million years ago, this process generated conditions for monsoon rainfall that accelerated the removal of carbon dioxide from the atmosphere at such a rate that global temperatures dropped dramatically and ushered in the Ice Ages.

Such an argument is difficult to clinch, but the latest research from NZ certainly lends support to the reasoning that new mountain chains are influential components in the climate machine.

Strenuous research

Larsen and colleagues calculate that the young, wet mountain chains of the world make up only 14% of the land area that drains into the ocean, but account for 62% of the sediment, 38% of the total dissolved solids and 60% of the dissolved silica delivered down the rivers and into estuaries and deltas and ultimately to the sea, where huge quantities of this run-off settle to become carbonate rock.

Mountains, in effect, are agencies that turn carbon dioxide from the air into limestone beneath the sea, and the evidence from the Southern Alps is that this happens more speedily than anyone first thought.

To complete the research, the scientists had repeatedly to take helicopter rides to the highest ridges, hike down to collect a burden of new soil, and then climb the steep mountain slopes again to await the return flight.

Back in Washington, they tested their soil samples for levels of beryllium-10, an isotope made at the Earth’s surface by cosmic rays, and therefore an indicator of the newness of the soil, and the rate at which it formed.

“I’ve worked in a lot of places,” said Larsen. “This was the most challenging fieldwork I have ever done.” – Climate News Network

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