Longdom Conferences

Speaker

Nov 18-19, 2019    Rome, Italy

Challenges in Global Climate Change

Tshering Thinley
12:40 PM-01:00 PM Hall 1

Tshering Thinley

Royal University of Bhutan Bhutan

Title: Free Electricity for Bhutan’s Rural Poor: Conservation Strategy

Biography: Tshering Thinley is a lecturer at Sherubtse College, Royal University of Bhutan. His research interests include aspects of environmental and resource economics, including health and pollution policies in developing and transition economies

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From Earth's deep mantle, scientists find a new way volcanoes form

2019-05-09

Far below Bermuda's pink sand beaches and turquoise tides, geoscientists have discovered the first direct evidence that material from deep within Earth's mantle transition zone -- a layer rich in water, crystals and melted rock -- can percolate to the surface to form volcanoes. Scientists have long known that volcanoes form when tectonic plates (traveling on top of the Earth's mantle) converge, or as the result of mantle plumes that rise from the core-mantle boundary to make hotspots at Earth's crust. But obtaining evidence that material emanating from the mantle's transition zone -- between 250 to 400 miles (440-660 km) beneath our planet's crust -- can cause volcanoes to form is new to geologists. "We found a new way to make volcanoes. This is the first time we found a clear indication from the transition zone deep in the Earth's mantle that volcanoes can form this way," said senior author Esteban Gazel, associate professor in the Department of Earth and Atmospheric Sciences at Cornell University. The research published in Nature. "We were expecting our data to show the volcano was a mantle plume formation -- an upwelling from the deeper mantle -- just like it is in Hawaii," Gazel said. But 30 million years ago, a disturbance in the transition zone caused an upwelling of magma material to rise to the surface, forming a now-dormant volcano under the Atlantic Ocean and then forming Bermuda. Using a 2,600-foot (over 700-meter) core sample -- drilled in 1972, housed at Dalhousie University, Nova Scotia -- co-author Sarah Mazza of the University of Münster, in Germany, assessed the cross-section for isotopes, trace elements, evidence of water content and other volatile material. The assessment provided a geologic, volcanic history of Bermuda. "I first suspected that Bermuda's volcanic past was special as I sampled the core and noticed the diverse textures and mineralogy preserved in the different lava flows," Mazza said. "We quickly confirmed extreme enrichments in trace element compositions. It was exciting going over our first results ... the mysteries of Bermuda started to unfold." From the core samples, the group detected geochemical signatures from the transition zone, which included larger amounts of water encased in the crystals than were found in subduction zones. Water in subduction zones recycles back to Earth's surface. There is enough water in the transition zone to form at least three oceans, according to Gazel, but it is the water that helps rock to melt in the transition zone. The geoscientists developed numerical models with Robert Moucha, associate professor of Earth sciences at Syracuse University, to discover a disturbance in the transition zone that likely forced material from this deep mantle layer to melt and percolate to the surface, Gazel said. Despite more than 50 years of isotopic measurements in oceanic lavas, the peculiar and extreme isotopes measured in the Bermuda lava core had not been observed

Amount of carbon stored in forests reduced as climate warms

2019-05-15

Accelerated tree growth caused by a warming climate does not necessarily translate into enhanced carbon storage, an international study suggests. The team, led by the University of Cambridge, found that as temperatures increase, trees grow faster, but they also tend to die younger. When these fast-growing trees die, the carbon they store is returned to the carbon cycle. The results, reported in the journal Nature Communications, have implications for global carbon cycle dynamics. As the Earth's climate continues to warm, tree growth will continue to accelerate, but the length of time that trees store carbon, the so-called carbon residence time, will diminish. During photosynthesis, trees and other plants absorb carbon dioxide from the atmosphere and use it to build new cells. Long-lived trees, such as pines from high elevations and other conifers found across the high-northern latitude boreal forests, can store carbon for many centuries. "As the planet warms, it causes plants to grow faster, so the thinking is that planting more trees will lead to more carbon getting removed from the atmosphere," said Professor Ulf Büntgen from Cambridge's Department of Geography, the study's lead author. "But that's only half of the story. The other half is one that hasn't been considered: that these fast-growing trees are holding carbon for shorter periods of time." Büntgen uses the information contained in tree rings to study past climate conditions. Tree rings are as distinctive as fingerprints: the width, density and anatomy of each annual ring contains information about what the climate was like during that particular year. By taking core samples from living trees and disc samples of dead trees, researchers are able to reconstruct how the Earth's climate system behaved in the past and understand how ecosystems were, and are, responding to temperature variation. For the current study, Büntgen and his collaborators from Germany, Spain, Switzerland and Russia, sampled more than 1100 living and dead mountain pines from the Spanish Pyrenees and 660 Siberian larch samples from the Russian Altai: both high-elevation forest sites that have been undisturbed for thousands of years. Using these samples, the researchers were able to reconstruct the total lifespan and juvenile growth rates of trees that were growing during both industrial and pre-industrial climate conditions. The researchers found that harsh, cold conditions cause tree growth to slow, but they also make trees stronger, so that they can live to a great age. Conversely, trees growing faster during their first 25 years die much sooner than their slow-growing relatives. This negative relationship remained statistically significant for samples from both living and dead trees in both regions. The idea of a carbon residence time was first hypothesised by co-author Christian Körner, Emeritus Professor at the University of Basel, but this is the first time that it has been confirmed by d

Fracking: Earthquakes are triggered well beyond fluid injection zones

2019-05-02

Using data from field experiments and modeling of ground faults, researchers at Tufts University have discovered that the practice of subsurface fluid injection used in 'fracking' and wastewater disposal for oil and gas exploration could cause significant, rapidly spreading earthquake activity beyond the fluid diffusion zone. Deep fluid injections -- greater than one kilometer deep -- are known to be associated with enhanced seismic activity -- often thought to be limited to the areas of fluid diffusion. Yet the study, published today in the journal Science, tests and strongly supports the hypothesis that fluid injections are causing potentially damaging earthquakes further afield by the slow slip of pre-existing fault fracture networks, in domino-like fashion. The results account for the observation that the frequency of human-made earthquakes in some regions of the country surpass natural earthquake hotspots. The study also represents a proof of concept in developing and testing more accurate models of fault behavior using actual experiments in the field. Much of our current understanding about the physics of geological faults is derived from laboratory experiments conducted at sample length scales of a meter or less. However, earthquakes and fault rupture occur over vastly larger scales. Observations of fault rupture at these larger scales are currently made remotely and provide poor estimates of the physical parameters of fault behavior that would be used to develop a model of human-made effects. More recently, the earthquake science community has put resources behind field-scale injection experiments to bridge the scale gap and understand fault behavior in its natural habitat. The researchers used data from these experimental field injections, previously conducted in France and led by a team of researchers based at the University of Aix-Marseille and the University of Nice Sophia-Antipolis. The experiments measured fault pressurization and displacement, slippage and other parameters that are fed into the fault-slip model used in the current study. The Tufts researchers' analysis provides the most robust inference to date that fluid-activated slippage in faults can quickly outpace the spread of fluid underground. "One important constraint in developing reliable numerical models of seismic hazard is the lack of observations of fault behavior in its natural habitat," said Pathikrit Bhattacharya, a former post-doc in the department of civil and environmental engineering at Tufts University's School of Engineering and lead author of the study. "These results demonstrate that, when available, such observations can provide remarkable insight into the mechanical behavior of faults and force us to rethink their hazard potential." Bhattacharya is now assistant professor in the School of Earth, Ocean and Climate Sciences at the Indian Institute of Technology in Bhubaneswar, India. The hazard posed by fluid-induced earthquakes is a matter

Australian islands home to 414 million pieces of plastic pollution

2019-05-16

A survey of plastic pollution on Australia's Cocos (Keeling) Islands has revealed the territory's beaches are littered with an estimated 414 million pieces of plastic debris. The study led by IMAS researcher Dr Jennifer Lavers and published in the journal Scientific Reports estimated beaches on the Indian Ocean islands are littered with 238 tonnes of plastic, including 977,000 shoes and 373,000 toothbrushes. Dr Lavers' research made headlines around the world when in May 2017 she revealed that beaches on remote Henderson Island in the South Pacific had the highest density of plastic debris reported anywhere on Earth. While the density of plastic debris on Cocos (Keeling) Islands beaches is lower than on Henderson Island, the total volume dwarfs the 38 million pieces weighing 17 tonnes found on the Pacific island. Dr Lavers said remote islands which don't have large human populations depositing rubbish nearby are an indicator of the amount of plastic debris circulating in the world's oceans. "Islands such as these are like canaries in a coal mine and it's increasingly urgent that we act on the warnings they are giving us," Dr Lavers said. "Plastic pollution is now ubiquitous in our oceans, and remote islands are an ideal place to get an objective view of the volume of plastic debris now circling the globe. "Our estimate of 414 million pieces weighing 238 tonnes on Cocos (Keeling) is conservative, as we only sampled down to a depth of 10 centimetres and couldn't access some beaches that are known debris 'hotspots'. "Unlike Henderson Island, where most identifiable debris was fishing-related, the plastic on Cocos (Keeling) was largely single-use consumer items such as bottle caps and straws, as well as a large number of shoes and thongs," Dr Lavers said. Co-author Dr Annett Finger from Victoria University said global production of plastic continues to increase, with almost half of the plastic produced over the past 60-years manufactured in the last 13 years. "An estimated 12.7 million tonnes of plastic entered our oceans in 2010 alone, with around 40 per cent of plastics entering the waste stream in the same year they're produced," Dr Finger said. "As a result of the growth in single-use consumer plastics, it's estimated there are now 5.25 trillion pieces of ocean plastic debris. "Plastic pollution is a well-documented threat to wildlife and its potential impact on humans is a growing area of medical research. "The scale of the problem means cleaning up our oceans is currently not possible, and cleaning beaches once they are polluted with plastic is time consuming, costly, and needs to be regularly repeated as thousands of new pieces of plastic wash up each day. "The only viable solution is to reduce plastic production and consumption while improving waste management to stop this material entering our oceans in the first place," Dr Finger said. The plastic survey on the beaches of Cocos (Keeling) Islands

GRACE data contributes to understanding of climate change

2019-05-25

The University of Texas at Austin team that led a twin satellite system launched in 2002 to take detailed measurements of the Earth, called the Gravity Recovery and Climate Experiment (GRACE), reports in the most recent issue of the journal Nature Climate Change on the contributions that their nearly two decades of data have made to our understanding of global climate patterns. Among the many contributions that GRACE has made: GRACE recorded three times the mass of ice lost in the polar and mountainous regions since first beginning measurements -- a consequence of global warming. GRACE enabled a measure of the quantity of heat added to the ocean and the location for said heat that remains stored in the ocean. GRACE has provided detailed observations, confirming that the majority of the warming occurs in the upper 2,000 meters of the oceans. GRACE has observed that of the 37 largest land-based aquifers, 13 have undergone critical mass loss. This loss, due to both a climate-related effect and an anthropogenic (human-induced) effect, documents the reduced availability of clean, fresh water supplies for human consumption. The information gathered from GRACE provides vital data for the federal agency United States Drought Monitor and has shed light on the causes of drought and aquifer depletion in places worldwide, from India to California. Intended to last just five years in orbit for a limited, experimental mission to measure small changes in the Earth's gravitational fields, GRACE operated for more than 15 years and has provided unprecedented insight into our global water resources, from more accurate measurements of polar ice loss to a better view of the ocean currents, and the rise in global sea levels. The mission was a collaboration between NASA and the German Aerospace Centre and was led by researchers in the Center for Space Research (CSR) in UT's Cockrell School of Engineering. UT's Texas Advanced Computing Center (TACC) has played a critical role in this international project over the last 15 years, according to Byron Tapley, the Clare Cockrell Williams Centennial Chair Emeritus in the Department of Aerospace Engineering and Engineering Mechanics who established the Center for Space Research at UT in 1981 and who served as principal investigator of the GRACE mission. "As the demand for the GRACE science deliverables have grown, TACC's ability to support these demands have grown. It has been a seamless transition to a much richer reporting environment," he said. By measuring changes in mass that cause deviations in the strength of gravity's pull on the Earth's various systems -- water systems, ice sheets, atmosphere, land movements, and more -- the satellites can measure small changes in the Earth system interactions. "By monitoring the physical components of the Earth's dynamical system as a whole, GRACE provides a time variable and holistic overview of how our oceans, atmosphere and land surface topography interact,"

Reductions in PM over decade has improved health; ozone pollution remains little changed

2019-05-26

Fewer deaths and serious illnesses have occurred in the U.S. over the past decade as a result of cleaner air, according to a new report focusing on the two most potent air pollutants: fine particle (PM2.5) and ground-level ozone (O3). However, these improvements are almost entirely due to reductions in PM2.5 pollution. The report, presented at ATS 2019 and published online in the Annals of the American Thoracic Society, is the latest in the annual "Health of the Air" series produced by the American Thoracic Society and the Marron Institute at NYU. The series estimates health impacts from air pollution for every U.S. city. In "Trends in Excess Morbidity and Mortality Associated with Air Pollution above ATS-Recommended Standards, 2008 to 2017," researchers report that mortality impacts of air pollution above these ATS-recommended levels fell by nearly half in the last decade as most U.S. counties have seen significant improvements in PM2.5, while health impacts from O3 pollution has "remained stubbornly high." The report's findings are based on the ATS's recommendations for PM2.5 (11 micrograms per cubic meter for annual concentrations and 25 micrograms per cubic meter for short-term concentrations) and O3 (60 parts per billion), which are more protective than those adopted by the U.S. Environmental Protection Agency. Using air quality data from more than 500 counties with PM2.5 data and more than 700 counties with O3 data, the researchers estimated the annual health impacts from air pollution from 2008-17. In 2017, the most recent year that pollution data is available, the number of excess deaths from air pollution were: 7,140 excess deaths from both pollutants combined, down from 12,600 excess deaths in 2010; 3,260 excess deaths from PM2.5, down from 8,330 excess deaths in 2010; 3,880 excess deaths from O3, down from 4,270 excess deaths in 2010. Based on the levels of the two pollutants, the researchers also quantified serious illnesses (morbidities) and missed school and work days (impacted days). In 2017, the most recent year that pollution data is available, PM2.5 pollution above recommended levels was estimated to cause an additional 5,600 morbidities and 2,804,000 impacted days. That same year, O3 pollution above recommended levels was estimated to cause 10,080 morbidities and 11,600,000 impacted days. Future Health of the Air The latest report found that in addition to the lack of consistent improvement in the health impacts associated with O3, the rate of improvement for PM2.5 pollution has also started to level off. Without further efforts at the federal and local levels to reduce the two air pollutants, it is likely that the health impacts from air pollution could increase over time as populations grow, according to the authors. The report also highlighted other challenges to reducing deaths and illness due to air pollution. "The proposed roll back of several Clean Air Act regulations and the proposed roll b

IMPROVED BIOMASS COOK STOVES :Early adoption benefits

2019-05-28

Biomass cooking will continue for the foreseeable future in most developing countries. However, inefficient cookstoves have a negative impact on well-being. While controversy surrounds whether improved biomass cookstoves effectively address this, a new st

GLOBAL CHANGE: Challenging life cycles

2019-05-29

Long-term data on sockeye salmon in Alaska shows how warmer temperatures during the juvenile freshwater stage of this species can drive shifts in later life history patterns.

Exposure to airborne metal pollution associated with increased risk of early mortality

2019-05-31

Although there is ample evidence that air pollution -- specifically airborne particulate matter -- is associated with an increased risk of premature death, it is still not known which specific particles are responsible for this effect. The Barcelona Institute for Global Health (ISGlobal), a research centre supported by "la Caixa," participated in a study that used wild moss samples to estimate human exposure to airborne metal particles in order to analyse the relationship between atmospheric metal pollution and risk of mortality. This unique study, based on an innovative approach, has been published in the journal Environment International. It included data from 11,382 participants belonging to the Gazel cohort who were living in rural areas throughout France, a cohort that had been followed up for 20 years. The data on mosses came from the BRAMM biovigilance programme, which collects and analyses moss samples from areas all over France situated at a distance from the country's largest industrial and population centres. These samples are analysed in the laboratory to measure the presence of 13 elements: aluminium, arsenic, calcium, cadmium, chromium, copper, iron, mercury, sodium, nickel, lead, vanadium and zinc. "There have been very few studies on the health effects of airborne metal pollutants, partly because of technical limitations, such as the lack of stations measuring air pollution. We thought that moss, because of its capacity to retain these metals, would be a useful tool for estimating the atmospheric metal exposure of people living in rural areas," explains Bénédicte Jacquemin, ISGlobal and INSERM researcher and last author of the study. The scientists constructed a mathematical model based on the geolocation data for each moss sample and the results of the BRAMM laboratory analysis. This model was then used to map the exposure of each participant to the metals under study. The metals were classified into two groups, according to whether their origin was considered natural or anthropogenic. The final analysis showed that participants exposed to higher atmospheric concentrations of metals of anthropogenic origin had an increased risk of death. The metals deemed to be of anthropogenic origin were cadmium, copper, mercury, lead and zinc. While all of these metals are naturally present in the earth's crust, their presence in the atmosphere is due to human activities, such as industry, traffic and heating. "Our results indicate that the metals present in the airborne particulate matter could be a key component in the effects of air pollution on mortality," explains Jacquemin. "It is important to bear in mind that the people we included in this study live in rural areas far from major urban and industrial centres and road networks. This means that they are very likely to be exposed to lower levels of air pollution than people living in urban environments, which gives us an idea of the seriousness of the health effects of air

Wind, warmth boost insect migration

2019-06-08

Wind and warmth can improve travel time for the billions of insects worldwide that migrate each year, according to a first-ever radio-tracking study by University of Guelph biologists. Researchers equipped monarch butterflies and green darner dragonflies with radio transmitters and tracked them through southern Ontario and several northern States to learn how environmental factors affect daytime insect migration. Learning more about what happens to insects during their physically taxing migration period may help in efforts to conserve them, particularly threatened species, said the researchers. The study, which was recently published in Biology Letters, found wind and temperature are more important influences than precipitation for bugs on autumn migration flights spanning thousands of kilometres between their breeding and wintering grounds. As part of their multigenerational migration, monarchs from Canada overwinter in Mexico and green darners travel to the southern United States. Until recently, their small size has made individual insects hard to track. But it's increasingly critical to do just that, said lead author Samantha Knight. Insects on the wing play vital roles in pollinating crops and in maintaining ecosystems as both prey and predators. Threatened by habitat loss, land use changes and global warming, she said, "some 40 per cent of insect species risk extinction, yet we know little about what happens to organisms when they migrate." Study co-author Prof. Ryan Norris, Department of Integrative Biology, added, "Migration is not an easy period for insects. They are likely pushed to their physiological limits. If we have a way to track and understand what habitats they're using, that goes a long way to understanding what might be causing declines." As part of the study, researchers captured insects on Ontario's Bruce Peninsula in fall 2015 and 2016 and outfitted them with battery-powered radio transmitters weighing about as much as a raindrop. Those devices emitted signals picked up by an array of telemetry towers across the southern part of the province and into the northern United States. The team downloaded data from the towers to track individuals' flight distances and speeds. On average, monarchs flew about 12 kilometres per hour and darners about 16 kilometres per hour. The farthest a monarch travelled in one day was 143 kilometres at 31 km per hour, including windspeed. In a single day, a darner flew 122 kilometres at up to 77 km per hour. "A darner would get a speeding ticket in Guelph," quipped Norris, adding that insects may fly even farther and faster in single spurts. To attain their fastest airspeeds, the insects are likely flying high in the atmosphere to take advantage of the wind, although the researchers don't know how high. "That means insects are migrating over our heads and we don't know it," said Norris. Unlike birds, insects need a minimum air temperature of about 10-15

Climate change and deforestation together push tropical species towards extinction

2019-06-11

Only 38 per cent of tropical forest is 'wildlife friendly' as a result of deforestation, increasing the likelihood that vulnerable species will go extinct, say scientists. Researchers from the University of Sheffield and University of York have discovered how deforestation and climate change -- two of the biggest drivers of species' extinction -- interact with each other to magnify their effects. For millennia, wildlife around the world has moved up and down mountains and towards or away from the equator to cope with changes in the Earth's temperature. The deforestation of tropical forests is creating a patchwork landscape where natural habitat is disconnected and confined to smaller spaces between a mass of farmland. The research found that most tropical forest habitat is currently too disconnected to provide pathways to cooler climates, meaning wildlife will struggle to escape the impacts of climate change. Tropical deforestation between 2000 -- 2012 led to a vast amount of forest area, bigger than India, losing its ability to link tropical wildlife with a habitat that would protect them from rising temperatures. Today, only 38 per cent of tropical forest allows resident wildlife to avoid climate warming by moving uphill or towards the poles. Senior author of the study, Professor David Edwards from the University of Sheffield, said: "The speed and severity with which the ability of plants and wildlife to track their optimal climates has been severed is truly shocking. "In considering what we can do to solve this problem, we urgently need to fund mechanisms to stop tropical forest loss whilst also investing in reforestation in places where deforestation has already been most severe. "The time to act is now and failure to do so will have catastrophic effects for tropical biodiversity over the coming century." This loss of forest means that if species move as far as possible to the coldest places along connected temperature gradients, then under severe warming scenarios species would still, on average, suffer 2.6 degrees Celsius in warming. Dr Rebecca Senior, who carried out this work whilst at the University of Sheffield's Department of Animal and Plant Sciences, said: "Our findings are cause for concern. We know that a huge amount of tropical rainforest has been and continues to be converted, but also that habitat loss is not the only threat to the natural world. "Our research is the first to investigate this interaction between habitat loss and climate change at such a large scale and over time. Almost everywhere is getting warmer and for tropical species sensitive to these increasing temperatures, the lack of escape routes to cooler habitats means that warming will likely result in national and global extinctions of vulnerable species."

Lead pollution in Arctic ice shows economic impact of wars and plagues for past 1,500 years

2019-06-14

How did events like the Black Death plague impact the economy of Medieval Europe? Particles of lead trapped deep in Arctic ice can tell us. Commercial and industrial processes have emitted lead into the atmosphere for thousands of years, from the mining and smelting of silver ores to make currency for ancient Rome to the burning of fossil fuels today. This lead pollution travels on wind currents through the atmosphere, eventually settling on places like the ice sheet in Greenland and other parts of the Arctic. Because of lead's connection to precious metals like silver and the fact that natural lead levels in the environment are very low, scientists have found that lead deposits in layers of Arctic ice are a sensitive indicator of overall economic activity throughout history. In a new study published in the Proceedings of the National Academy of Sciences, researchers from the Desert Research Institute (DRI), the University of Oxford, NILU -- Norwegian Institute for Air Research, the University of Copenhagen, the University of Rochester, the Alfred Wegener Institute for Polar and Marine Research used thirteen Arctic ice cores from Greenland and the Russian Arctic to measure, date, and analyze lead emissions captured in the ice from 500 to 2010 CE, a period of time that extended from the Middle Ages through the Modern Period to the present. This work builds on a study published by some of the same researchers in 2018, which showed how lead pollution in a single ice core from Greenland tracked the ups and downs of the European economy between 1100 BCE and 800 CE, a period which included the Greek and Roman empires. "We have extended our earlier record through the Middle Ages and Modern Period to the present," explained Joe McConnell, Ph.D., lead author on the study and Director of DRI's Ultra-Trace Ice Core Chemistry Laboratory in Reno, Nevada. "Using an array of thirteen ice cores instead of just one, this new study shows that prior to the Industrial Revolution, lead pollution was pervasive and surprisingly similar across a large swath of the Arctic and undoubtedly the result of European emissions. The ice-core array provides with amazing detail a continuous record of European -- and later North American -- industrial emissions during the past 1500 years." "Developing and interpreting such an extensive array of Arctic ice-core records would have been impossible without international collaboration," McConnell added. The research team found that increases in lead concentration in the ice cores track closely with periods of expansion in Europe, the advent of new technologies, and economic prosperity. Decreases in lead, on the other hand, paralleled climate disruptions, wars, plagues, and famines. "Sustained increases in lead pollution during the Early and High Middle Ages (about 800 to 1300 CE), for example, indicate widespread economic growth, particularly in central Europe as new mining areas were discovered in places like th

Breaching a 'carbon threshold' could lead to mass extinction

2019-06-16

Carbon dioxide emissions may trigger a reflex in the carbon cycle, with devastating consequences, study finds. In the brain, when neurons fire off electrical signals to their neighbors, this happens through an "all-or-none" response. The signal only happens once conditions in the cell breach a certain threshold. Now an MIT researcher has observed a similar phenomenon in a completely different system: Earth's carbon cycle. Daniel Rothman, professor of geophysics and co-director of the Lorenz Center in MIT's Department of Earth, Atmospheric and Planetary Sciences, has found that when the rate at which carbon dioxide enters the oceans pushes past a certain threshold -- whether as the result of a sudden burst or a slow, steady influx -- the Earth may respond with a runaway cascade of chemical feedbacks, leading to extreme ocean acidification that dramatically amplifies the effects of the original trigger. This global reflex causes huge changes in the amount of carbon contained in the Earth's oceans, and geologists can see evidence of these changes in layers of sediments preserved over hundreds of millions of years. Rothman looked through these geologic records and observed that over the last 540 million years, the ocean's store of carbon changed abruptly, then recovered, dozens of times in a fashion similar to the abrupt nature of a neuron spike. This "excitation" of the carbon cycle occurred most dramatically near the time of four of the five great mass extinctions in Earth's history. Scientists have attributed various triggers to these events, and they have assumed that the changes in ocean carbon that followed were proportional to the initial trigger -- for instance, the smaller the trigger, the smaller the environmental fallout. But Rothman says that's not the case. It didn't matter what initially caused the events; for roughly half the disruptions in his database, once they were set in motion, the rate at which carbon increased was essentially the same. Their characteristic rate is likely a property of the carbon cycle itself -- not the triggers, because different triggers would operate at different rates. What does this all have to do with our modern-day climate? Today's oceans are absorbing carbon about an order of magnitude faster than the worst case in the geologic record -- the end-Permian extinction. But humans have only been pumping carbon dioxide into the atmosphere for hundreds of years, versus the tens of thousands of years or more that it took for volcanic eruptions or other disturbances to trigger the great environmental disruptions of the past. Might the modern increase of carbon be too brief to excite a major disruption? According to Rothman, today we are "at the precipice of excitation," and if it occurs, the resulting spike -- as evidenced through ocean acidification, species die-offs, and more -- is likely to be similar to past global catastrophes. "Once we're over the threshold, how we got there ma

How much do climate fluctuations matter for global crop yields?

2019-06-18

The El Niño-Southern Oscillation has been responsible for widespread, simultaneous crop failures in recent history, according to a new study from researchers at Columbia University's International Research Institute for Climate and Society, the International Food Policy Research Institute (IFPRI) and other partners. This finding runs counter to a central pillar of the global agriculture system, which assumes that crop failures in geographically distant breadbasket regions such as the United States, China and Argentina are unrelated. The results also underscore the potential opportunity to manage such climate risks, which can be predicted using seasonal climate forecasts.

A clearer picture of global ice sheet mass

2019-06-20

Fluctuations in the masses of the world's largest ice sheets carry important consequences for future sea level rise, but understanding the complicated interplay of atmospheric conditions, snowfall input and melting processes has never been easy to measure due to the sheer size and remoteness inherent to glacial landscapes. Much has changed for the better in the past decade, according to a new review paper co-authored by researchers at the University of Colorado Boulder, NASA, Utrecht University and Delft University of Technology and recently published in the Review of Geophysics. The study outlines improvements in satellite imaging and remote sensing equipment that have allowed scientists to measure ice mass in greater detail than ever before. "We've come a long way in the last 10 years from an observational perspective," said Jan Lenaerts, lead author of the research and an assistant professor in CU Boulder's Department of Atmospheric and Oceanic Sciences (ATOC). "Knowing what happens to ice sheets in terms of mass in, mass out allows us to better connect climate variations to ice mass and how much the mass has changed over time." Ice sheets primarily gain mass from precipitation and lose it due to solid ice discharge and runoff of melt water. Precipitation and runoff, along with other surface processes, collectively determine the surface mass balance. The Antarctic Ice Sheet, the world's largest, is cold year-round with only marginal summer melting. A small increase or decrease in yearly snowfall, then, can make a considerable difference in surface mass because the addition or subtraction is compounded over a massive area. "Snowfall is dominant over Antarctica and will stay that way for the next few decades," Lenaerts said. "And we've seen that as the atmosphere warms due to climate change, that leads to more snowfall, which somewhat mitigates the loss of ice sheet mass there. Greenland, by contrast, experiences abundant summer melt, which controls much of its present and future ice loss." In years past, climate models would have been unable to render the subtleties of snowfall in such a remote area. Now, thanks to automated weather stations, airborne sensors and Earth-orbit satellites such as NASA's Gravity Recovery and Climate experiment (GRACE) mission, these models have been improved considerably. They produce realistic ice sheet surface mass balance, allow for greater spatial precision and account for regional variation as well as wind-driven snow redistribution -- a degree of detail that would have been unheard of as recently as the early 2000s. "If you don't have the input variable right, you start off on the wrong foot," Lenaerts said. "We've focused on snowfall because it heavily influences the ice sheet's fate. Airborne observations and satellites have been instrumental in giving a better view of all these processes." Ground-based radar systems and ice core samples provide a useful historical archive, allowing

Shifts to renewable energy can drive up energy poverty, study finds

2019-06-23

Efforts to shift away from fossil fuels and replace oil and coal with renewable energy sources can help reduce carbon emissions but do so at the expense of increased inequality, according to a new Portland State University study. Julius McGee, assistant professor of sociology in PSU's College of Liberal Arts and Sciences, and his co-author, Patrick Greiner, an assistant professor of sociology at Vanderbilt University, found in a study of 175 nations from 1990 to 2014 that renewable energy consumption reduces carbon emissions more effectively when it occurs in a context of increasing inequality. Conversely, it reduces emissions to a lesser degree when occurring in a context of decreasing inequality. Their findings, published recently in the journal Energy Research & Social Science, support previous claims by researchers who argue that renewable energy consumption may be indirectly driving energy poverty. Energy poverty is when a household has no or inadequate access to energy services such as heating, cooling, lighting, and use of appliances due to a combination of factors: low income, increasing utility rates, and inefficient buildings and appliances. McGee said that in nations like the United States where fossil fuel energy is substituted for renewable energy as a way to reduce carbon emissions, it comes at the cost of increased inequality. That's because the shift to renewable energy is done through incentives such as tax subsidies. This reduces energy costs for homeowners who can afford to install solar panels or energy-efficient appliances, but it also serves to drive up the prices of fossil fuel energy as utility companies seek to recapture losses. That means increased utility bills for the rest of the customers, and for many low-income families, increased financial pressure, which creates energy poverty. "People who are just making ends meet and can barely afford their energy bills will make a choice between food and their energy," McGee said. "We don't think of energy as a human right when it actually is. The things that consume the most energy in your household -- heating, cooling, refrigeration -- are the things you absolutely need." Alternatively, in poorer nations, renewable sources of electricity have been used to alleviate energy poverty. In rural areas in southeast Asia and sub-Saharan Africa, a solar farm can give an agrarian community access to electricity that historically never had access to energy, McGee said. "That's not having any impact on carbon dioxide emissions because those rural communities never used fossil fuels in the first place," he said. The study recommends that policymakers consider implementing policy tools that are aimed at both reducing inequality and reducing emissions. McGee and Greiner said such policies would both incentivize the implementation of renewable energy resources, while also protecting the populations that are most vulnerable to energy poverty. "We really need to think m

New model suggests lost continents for early Earth

2019-06-25

A new radioactivity model of Earth's ancient rocks calls into question current models for the formation of Earth's continental crust, suggesting continents may have risen out of the sea much earlier than previously thought but were destroyed, leaving little trace. Scientists at the University of Adelaide have published two studies on a model of rock radioactivity over billions of years which found that the Earth's continental crust may have been thicker, much earlier than current models suggest, with continents possibly present as far back as four billion years. "We use this model to understand the evolving processes from early Earth to the present, and suggest that the survival of the early crust was dependent on the amount of radioactivity in the rocks -- not random chance," says Dr Derrick Hasterok, from the University of Adelaide's Department of Earth Sciences and Mawson Centre for Geoscience. "If our model proves to be correct, it may require revision to many aspects of our understanding of the Earth's chemical and physical evolution, including the rate of growth of the continents and possibly even the onset of plate tectonics." Dr Hasterok and his PhD student Matthew Gard compiled 75,800 geochemical samples of igneous rocks (such as granite) with estimated ages of formation from around the continents. They estimated radioactivity in these rocks today and constructed a model of average radioactivity from four billion years ago to the present. "All rocks contain natural radioactivity that produces heat and raises temperatures in the crust when it decays -- the more radioactive a rock the more heat it produces," says Dr Hasterok. "Rocks typically associated with the continental crust have higher radioactivity than oceanic rocks. A rock four billion years old would have about four times as much radioactivity when it was created compared with today." But the researchers found an unexpected deficit in the level of radioactivity in rocks older than about two billion years. When they corrected for higher heat production, because of the higher radioactivity that would have been present, the deficit disappeared. "We think there would have been more granite-like -- or continental-type -- rocks around but because of the higher radioactivity, and therefore higher heat, they either melted or were easily destroyed by tectonic movement. That's why these continental crusts don't show in the geological record. "Our prevailing models suggest that continents eventually grew out of the oceans as the crust thickened. But we think there may have been significant amount of, albeit very unstable, continental crust much earlier." Co-author Professor Martin Hand, also from the University of Adelaide, says the new model could have important implications for monitoring the effects of global warming. "What this new model allows us to do is help predict rock radioactivity in places where we have few or no samples, like Antarctica, where we c

How trees could save the climate

2019-06-28

Around 0.9 billion hectares of land worldwide would be suitable for reforestation, which could ultimately capture two thirds of human-made carbon emissions. The Crowther Lab of ETH Zurich has published a study in the journal Science that shows this would be the most effective method to combat climate change. The Crowther Lab at ETH Zurich investigates nature-based solutions to climate change. In their latest study the researchers showed for the first time where in the world new trees could grow and how much carbon they would store. Study lead author and postdoc at the Crowther Lab Jean-François Bastin explains: "One aspect was of particular importance to us as we did the calculations: we ex-cluded cities or agricultural areas from the total restoration potential as these areas are needed for hu-man life." Reforest an area the size of the USA The researchers calculated that under the current climate conditions, Earth's land could support 4.4 billion hectares of continuous tree cover. That is 1.6 billion more than the currently existing 2.8 billion hectares. Of these 1.6 billion hectares, 0.9 billion hectares fulfill the criterion of not being used by hu-mans. This means that there is currently an area of the size of the US available for tree restoration. Once mature, these new forests could store 205 billion tonnes of carbon: about two thirds of the 300 billion tonnes of carbon that has been released into the atmosphere as a result of human activity since the Industrial Revolution. According to Prof. Thomas Crowther, co-author of the study and founder of the Crowther Lab at ETH Zurich: "We all knew that restoring forests could play a part in tackling climate change, but we didn't really know how big the impact would be. Our study shows clearly that forest restoration is the best climate change solution available today. But we must act quickly, as new forests will take decades to mature and achieve their full potential as a source of natural carbon storage." Russia best suited for reforestation The study also shows which parts of the world are most suited to forest restoration. The greatest po-tential can be found in just six countries: Russia (151 million hectares); the US (103 million hectares); Canada (78.4 million hectares); Australia (58 million hectares); Brazil (49.7 million hectares); and China (40.2 million hectares). Many current climate models are wrong in expecting climate change to increase global tree cover, the study warns. It finds that there is likely to be an increase in the area of northern boreal forests in re-gions such as Siberia, but tree cover there averages only 30 to 40 percent. These gains would be out-weighed by the losses suffered in dense tropical forests, which typically have 90 to 100 percent tree cover. Look at Trees! A tool on the Crowther Lab website (https://www.crowtherlab.com/maps-2/) enables users to look at any point on the globe, and find out how many trees could grow there and how

Top climate risks for Canada, potential for adaptation

2019-07-01

An expert panel convened by the Council of Canadian Academies (CCA) has identified Canada's top climate change risks and determined that many costs and damages could be avoided with prompt and thoughtful adaptation. Canada's climate is changing, with recent research showing that temperatures are rising twice as fast as the global average. Over the next 20 years, Canada can expect more frequent and severe hot extremes, thawing of permafrost, and increases in extreme precipitation. "Climate change is increasingly leading to costly and disruptive impacts, and current projections suggest the warming in Canada and globally will continue, regardless of the trajectory of global emissions," said L. John Leggat, PhD, FCAE, Chair of the Expert Panel. "Understanding our top climate change risks and the role of adaptation in reducing these risks can help to support an effective response." The Treasury Board of Canada Secretariat asked the CCA to examine the top climate change risks for Canada and their relative significance. Other studies have examined climate change risks at the sectoral and departmental level, but few have taken government-wide approach designed to help prioritize government responses. Canada's Top Climate Change Risks identifies the top risk areas based on the extent and likelihood of the potential damage, and rates the risk areas according to society's ability to adapt and reduce negative outcomes. These 12 major areas of risk are: agriculture and food, coastal communities, ecosystems, fisheries, forestry, geopolitical dynamics, governance and capacity, human health and wellness, Indigenous ways of life, northern communities, physical infrastructure, and water. The report describes an approach to inform federal risk prioritization and adaptation responses. The Panel outlines a multi-layered method of prioritizing adaptation measures based on an understanding of the risk, adaptation potential, and federal roles and responsibilities. "Canada's unique geographic, environmental, and social identity shapes the hazards that it faces and its exposure to climate-related risks," said Eric M. Meslin, PhD, FCAHS, President and CEO of the CCA. "This report represents a high-level approach to prioritizing those risks, which we hope will help inform decision making about adaptation approaches."

Improved model could help scientists better predict crop yield, climate change effects

2019-07-05

A new computer model incorporates how microscopic pores on leaves may open in response to light -- an advance that could help scientists create virtual plants to predict how higher temperatures and rising levels of carbon dioxide will affect food crops, according to a study published in a special July 2019 issue of the journal Photosynthesis Research. "This is an exciting new computer model that could help us make much more accurate predictions across a wide range of conditions," said Johannes Kromdijk, who led the work as part of an international research project called Realizing Increased Photosynthetic Efficiency (RIPE). RIPE, which is led by the University of Illinois, is engineering crops to be more productive without using more water by improving photosynthesis, the natural process all plants utilize to convert sunlight into energy to fuel growth and crop yields. RIPE is supported by the Bill & Melinda Gates Foundation, the U.S. Foundation for Food and Agriculture Research (FFAR), and the U.K. Government's Department for International Development (DFID). The current work focused on simulating the behavior of what are known as stomata -- microscopic pores in leaves that, in response to light, open to allow water, carbon dioxide, and oxygen to enter and exit the plant. In 2018, the RIPE team published a paper in Nature Communications that showed increasing one specific protein could prompt plants to close their stomata partially -- to a point where photosynthesis was unaffected, but water loss decreased significantly. This study's experimental data was used to create the newly improved stomata model introduced today. "We've known for decades that photosynthesis and stomatal opening are closely coordinated, but just how this works has remained uncertain," said Stephen Long, Ikenberry Endowed University Chair of Crop Sciences and Plant Biology at the University of Illinois. "With this new computer model, we have a much better tool for calculating stomatal movements in response to light." The ultimate goal, Long said, is to identify opportunities to control these stomatal gatekeepers to make drought-tolerant crops. "Now we're closing in on the missing link: How photosynthesis tells stomates when to open." Computer modeling has been a major advance in crop breeding. The father of modern genetics, Gregor Mendel, made his breakthrough discovery that pea plants inherit traits from their parents by growing and breeding more than 10,000 pea plants over eight years. Today, plant scientists can virtually grow thousands of crops in a matter of seconds using these complex computer models that simulate plant growth. Stomatal models are used together with models for photosynthesis to make wide-ranging predictions from future crop yields to crop management, such as how crops respond when there is a water deficit. In addition, these models can give scientists a preview of how crops like wheat, maize, or rice could be affected by rising ca

How to produce natural gas while storing carbon dioxide

2019-07-10

New research at The University of Texas at Austin shows that injecting air and carbon dioxide into methane ice deposits buried beneath the Gulf of Mexico could unlock vast natural gas energy resources while helping fight climate change by trapping the carbon dioxide underground. The study, published June 27 in the journal Water Resources Research, used computer models to simulate what happens when mixtures of carbon dioxide and air are injected into deposits of methane hydrate, an ice-like, water-rich chemical compound that forms naturally in high-pressure, low-temperature environments, such as deep in the Gulf of Mexico and under Arctic permafrost. Lead author Kris Darnell, a recent doctoral graduate from the UT Jackson School of Geosciences, said the research is the next step in solving two significant global challenges: energy security and carbon storage. "Our study shows that you can store carbon dioxide in hydrates and produce energy at the same time," said Darnell, whose research was funded by the University of Texas Institute for Geophysics (UTIG). In the process, the nitrogen in the injected air sweeps the methane toward a production well and allows carbon dioxide to take its place, researchers said. The beauty of this approach is that it extracts natural gas from methane hydrate deposits and at the same time stores carbon dioxide, a greenhouse gas, in a deep environment where it is unlikely to be released into the atmosphere where it could contribute to climate change. This is not the first time that hydrate deposits have been proposed for carbon dioxide storage. Earlier attempts either failed or produced lackluster results. The new study breaks down the physics behind the process to reveal why previous attempts failed and how to get it right. The next step, said Darnell, is to test their findings in a lab. The Jackson School and the UT Hildebrand Department of Petroleum and Geosystems Engineering are currently testing the method in a specialized facility in the Jackson School, which is one of the few in the world that can store and test methane hydrate. This work is being led by Peter Flemings, a Jackson School professor and senior UTIG research scientist, and David DiCarlo, a professor in the Hildebrand Department. Both are co-authors on the paper. "Two things are really cool. First, we can produce natural gas to generate energy and sequester CO2," said Flemings. "Second, by swapping the methane hydrate with CO2 hydrate, we disturb the (geologic) formation less, lowering the environmental impact, and we make the process energetically more efficient." If the process can be shown to work in the field on an industrial scale, it has enormous potential. Methane hydrate is one of a group of chemical compounds known as gas hydrates in which gas molecules become trapped inside cages of water ice molecules rather than chemically bonding with them. UT and the U.S. Department of Energy (DOE) are working together to stud

Applying pressure is way toward generating more electricity from waste heat

2019-07-14

Researchers at Osaka University have been able to enhance the power factor of a promising thermoelectric material by more than 100% by varying the pressure, paving the way for new materials with improved thermoelectric properties. Thermoelectric materials have the unique ability to generate electricity from temperature differences and therefore could potentially be used to convert otherwise wasted heat (such as heat from hot laptops or servers) into usable electricity. In addition to improving the thermoelectric properties of a material, the researchers revealed that the material's thermoelectric properties originate from a transition in the topology of the electronic band structure, which is referred to as the Lifshitz transition. This transition differs from the conventional Landau-type phase transition, because it occurs without any symmetry breaking. Researchers have long had reason to believe that the Lifshitz transition plays a crucial role in many quantum phenomena, such as superconductivity, complex magnetism, and thermoelectric properties, but they lacked direct proof. In this new study, Osaka University researchers have shown a direct link between the Lifshitz transition and physical properties in a thermoelectric material. "We were able to keep track of the Lifshitz transition by applying pressure and measuring the quantum oscillations as the pressure was increased," corresponding author Hideaki Sakai says. The researchers studied tin selenide (SnSe), a thermoelectric material that is also a semiconductor with a small amount of conducting carriers. In semiconductors the lower energy valence band is filled with electrons whereas the higher energy conduction band is empty of them; once some impurities and/or chemical defects are introduced, conducting carriers are introduced as electrons and holes in the conduction and valence bands, respectively, and the semiconductor will behave like a conductor. Apart from having an effect on the material's electrical conduction properties, the band structure also has an effect on quantum phenomena, such as their thermoelectric abilities. The valence bands of tin selenide are not completely flat, but normally have two valleys in them. "When we increased the pressure on the material, we observed a change from two to four valleys in the material when the Lifshitz transition occurred," Hideaki Sakai says. The researchers were able to show both experimentally and theoretically that this change in the number of valleys was directly responsible for significantly improving tin selenide's thermoelectric properties. The results of the study may help prepare improved thermoelectric materials in the future and could also help clarify the effect of the Lifshitz transition on various transport properties, leading to potential applications such as novel electronics utilizing valley degrees of freedom in the band structure.

Solar energy could turn the Belt and Road Initiative green

2019-07-15

The region covered by the Belt and Road Initiative (BRI) has significant potential to be powered by solar energy, researchers report June 27 in the journal Joule. Less than 4 percent of the maximum solar potential of the region could meet the BRI's electricity demand for 2030. The research suggests a possible solution to reduce BRI countries' need for fossil fuels as they develop. This is the first time the renewable energy potential of the region is quantified. The Chinese government launched the BRI in 2013, aiming to promote regional development and connectivity. "Belt" represents the Silk Road Economic Belt that echoes the ancient Silk Road, which linked Asia to Europe. "Road" refers to the 21st Century Maritime Silk Road that connects China to South East Asia, South Asia, and North Africa. So far, more than 120 countries in Asia, Europe, Africa, North America, South America, and Oceania are involved. Constructing hard infrastructure, such as railways, buildings, and power plants, is a main focus of the initiative. However, most of the projects use large amounts of energy, resulting in high emissions. In addition, most countries involved in the BRI are developing countries. A proportion of their population doesn't have access to electricity. As the region develops under the initiative, the need for power is projected to increase. "If we continue to rely on fossil fuels for energy, it can add significantly more CO2 to the atmosphere, not just this year, but for the next few decades," says co-author Xi Lu at Tsinghua University. "This is not sustainable. If we want to achieve the emission reduction goal set by the Paris Agreement, we need renewable energy." Many BRI countries, especially those in West and South Asia, have high sun exposure, so Lu and his colleagues decided to assess the region's solar resource. The team selected 66 BRI countries that are connected geographically and built an integrative spatial model to calculate their solar power potential with high-resolution data. The team first identified areas suitable for building solar farms. These areas would receive sufficient solar radiation and have lower land value otherwise -- places like forests and agriculture land are excluded. Then they computed the spacing and packing density of solar panels, which absorb sunlight and generate energy, that would maximize power yield for each area. Finally, they calculated the areas' energy outputs in each hour after considering limiting factors like shading and temperature, which affects the performance of solar panels. "Our model provides a comprehensive analysis of the region's solar energy potential by taking into account many influencing factors," Lu says. "We also calculated the solar energy outputs on an hourly basis, which is more accurate than previous estimates that use monthly data." The team found that these countries can generate as much as 448.9 petawatt hour of energy, which is about 41 times the demand for e

Warming climate intensifes summer drought in parts of US

2019-07-16

Climate change is amplifying the intensity and likelihood of heatwaves during severe droughts in the southern plains and southwest United States, according to a new study by a University of Arkansas researcher. Linyin Cheng, assistant professor of geosciences, used data from the National Center for Atmospheric Research's Community Earth System Model to study summer droughts that occurred both before and after the Industrial Revolution. Cheng and colleagues from the National Oceanic and Atmospheric Administration and universities in China and Colorado ran simulations to assess how, and by how much, human-induced climate change affects summer heatwaves in the contiguous United States. The study was published in the Journal of Climate. The researchers found that in places with low moisture in the soil, such as the southern plains and southwest, higher temperatures brought about by climate change led to an increased "coupling" of land and atmosphere, which further increased the severity of heatwaves. In places with more moisture in the soil, such as the northeast, they found no appreciable coupling and therefore no contribution to heatwave intensification. "Our analysis of climate simulation finds that summertime drought-heatwave relationships change significantly over the southern and southwest U.S. due to human-made climate change since the late 19th century," said Cheng. "By contrast, the drought-heatwave relationship over northern U.S regions undergoes little change in the warmed climate." The findings raise the idea of a self-reinforcing climate loop: as a region's climate becomes more arid due to climate change, droughts become hotter, further reducing soil moisture. "Overall, these results indicate that strengthened land-atmosphere feedback is a significant physical driver for increasing occurrences of drought-related extreme heatwaves, particularly over the semi-arid and arid regions of the United States," the report states.

Rising CO2, climate change projected to reduce availability of nutrients worldwide

2019-08-18

One of the biggest challenges to reducing hunger and undernutrition around the world is to produce foods that provide not only enough calories but also make enough necessary nutrients widely available. New research finds that, over the next 30 years, climate change and increasing carbon dioxide (CO2) could significantly reduce the availability of critical nutrients such as protein, iron, and zinc, compared to a future without it. The total impacts of climate change shocks and elevated levels of CO2 in the atmosphere are estimated to reduce growth in global per capita nutrient availability of protein, iron, and zinc by 19.5%, 14.4%, and 14.6%, respectively. "We've made a lot of progress reducing undernutrition around the world recently but global population growth over the next 30 years will require increasing the production of foods that provide sufficient nutrients," explained Senior Scientist at the International Food Policy Research Institute (IFPRI) and study co-author Timothy Sulser. "These findings suggest that climate change could slow progress on improvements in global nutrition by simply making key nutrients less available than they would be without it." The study, "A modeling approach combining elevated atmospheric CO2 effects on protein, iron and zinc availability with projected climate change impacts on global diets," [LINK] was co-authored by an international group of researchers and published in the peer-reviewed journal, Lancet Planetary Health. The study represents the most comprehensive synthesis of the impacts of elevated CO2 and climate change on the availability of nutrients in the global food supply to date. Using the IMPACT global agriculture sector model along with data from the Global Expanded Nutrient Supply (GENuS) model and two data sets on the effects of CO2 on nutrient content in crops, researchers projected per capita availability of protein, iron, and zinc out to 2050. Improvements in technology, and markets effects are projected to increase nutrient availability over current levels by 2050, but these gains are substantially diminished by the negative impacts of rising concentrations of carbon dioxide. While higher levels of CO2 can boost photosynthesis and growth in some plants, previous research has also found they reduce the concentration of key micronutrients in crops. The new study finds that wheat, rice, maize, barley, potatoes, soybeans, and vegetables are all projected to suffer nutrient losses of about 3% on average by 2050 due to elevated CO2 concentration. The effects are not likely to be felt evenly around the world, however, and many countries currently experiencing high levels of nutrient deficiency are also projected to be more affected by lower nutrient availability in the future. Nutrient reductions are projected to be particularly severe in South Asia, the Middle East, Africa South of the Sahara, North Africa, and the former Soviet Union -- regions largely comprised of low- and

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