Extreme rainfall acidifies land in India's northeastern states

Large parts of the northeastern states’ land area are degraded, says a new draft report on land degradation prepared by the Indian Space Research Organisation’s (ISRO) National Remote Sensing Centre (NRSC). Among the top seven states with the highest increase in land degradation in the last 10 years, six are in the northeast. After Uttar Pradesh and Rajasthan, which have 53 percent and 52 percent degraded land area, Nagaland stands third with 47 percent of its land area under degradation. In Manipur, Mizoram, and Meghalaya, 38, 35 and 28 percent of the land is degraded. One of the major causes of this degradation could be an increased frequency of high rainfall events in the region. The degradation could, in fact, be one of the reasons for the devastating surface floods, flash floods and landslides throughout the northeastern region of the country this year. Five states—Assam, Manipur, Tripura, Mizoram, and Nagaland—suffered from minor to major floods in 2018. This would mean that the floods and land degradation are turning into a vicious cycle for the northeastern population. But more than water erosion, which worsens floods, the report finds that the most common cause of land degradation in these states is acidification. In the top eight states in the country where acidification is the most rampant, seven are in the northeast. The highest among these is Nagaland where almost 7.5 lakh hectares of land area is acidic which constitutes around 45 percent of the total area of the state. Manipur comes second with 6.3 lakh hectare acidified land, which is more than 28 percent of its total geographical area. Only in the states of Arunachal Pradesh and Assam, the degradation has been caused by water erosion is greater than that caused by acidification with the latter having water logging as another major concern. Acidity is measured in terms of the concentration of hydrogen ions (pH) in the soil as they are essential for the formation of all acids. Acidification of soil or land takes place when the pH balance of the soil shifts towards acidic nature due to an excessive presence of hydrogen ions. Soil acidity increases when metallic minerals like calcium, magnesium, potassium, and sodium are lost from the soil and only hydrogen ions remain. These minerals get removed from soils due to heavy rainfall and flooding. They also get removed along with the residues of crops or hay during harvest. Land in the northeast is naturally acidic because of the heavy rainfall it receives every year but climate change induced high frequency of heavy rainfall events will further exacerbate the acidification. This acidification decreases the quality of soil and reduces their productivity significantly. In a region that is predominantly dependant on agriculture, with 70 percent of the population engaged in farming, such loss of arable land and at an increased rate could spell doom for the people’s livelihood. One way that this situation can be rectified is by using lime and organic manures in the soil. Acidification can also be remedied by adopting nutrient management practices and smart crop selection.

Extreme heat increasing in both summer and winter

A new study in the in Journal of Geophysical Research: Atmospheres, a publication of the American Geophysical Union, examined absolute extreme temperatures -- high temperatures in summer and low temperatures in winter -- but also looked at relative extreme temperature events -- unusually cold temperatures and unusually warm temperatures throughout the year. The new study found both relative and absolute extreme heat events have increased across the US and Canada since 1980. This upward trend is greatest across the southern US, especially in the Ozarks and southern Arizona, as well as northern Quebec. That means there are more extremely hot days during the summer as well as more days that are considered extremely hot for the time of year, like abnormally warm days in the winter. The new research also found both relative and absolute extreme cold events are decreasing, most notably in Alaska and Northern Canada, along with patches along the US Atlantic coast. In these areas, there are fewer instances of temperatures that are extremely cold either compared to the normal range, like in winter, or for the time of year, like unusually cold days in the summer. Global mean surface temperature, the most frequently cited indicator of climate change, has been steadily increasing since the 1970s. However, temperature extremes pose a greater ecological risk to many species than average warming, according to the study's authors. The new study is one of the first to explore relative extreme temperature events, which are changing more rapidly than absolute temperature extremes, and can have important implications for the environment, agriculture and human health, according to Scott Sheridan, professor in the department of geography at Kent State University and lead author of the new study. "Typically for this kind of research we look at the highest temperatures in the summer and lowest temperatures in the winter. But we've also seen that extreme temperatures that are really anomalous for the time of year can have a high impact -- these relative extremes are important and underappreciated," he said.

Investigating temperature extremes

To investigate how extreme temperature events have been changing over time, Sheridan and his co-author conducted a climatology of cold and heat events, both absolute and relative, for North America, followed by an analysis of how they have changed from 1980-2016. Relative extreme temperature events are changing faster than absolute extreme events, and often occur outside of seasonal norms, according to the new study. In the eastern half of the US, relative extreme heat events occur as early as mid-winter into early spring. Out-of-season extreme temperatures can cause early thaws in mild winters or catch vulnerable populations unprepared and unacclimated. Across parts of the Arctic, extreme cold events have become almost entirely nonexistent and increasingly difficult to identify, according to the researchers. "Relative temperature anomalies can trigger what is called phenological mismatches, where a mismatch in the temperature and the season can cause trees to bloom too early and birds and insects to migrate before there is appropriate food," Sheridan said. Most notable is the highly anomalous warm event in March 2012, which included persistent mid-summer warmth in multiple locations. The event produced a 'false spring' in which vegetation prematurely left dormancy, so that it was not prepared for subsequent frosts, leading to large agricultural losses in certain areas, according to the researchers. There is some evidence that early-season heat events are more hazardous to humans than heat events later in the season. When people are not acclimatized to hotter temperatures, they are more vulnerable to negative health impacts, especially the elderly, infants, young children, and people with chronic health problems or disabilities, according to the researchers. The study clearly underlines the importance of not just looking at high temperatures in the summer but also looking at relative temperatures, said Kristie Ebi, professor of Environmental and Occupational Health Sciences at the University of Washington, who was not involved in the study. "Using information generated in the study on regional patterns in extreme weather events, particularly relative extremes in temperature, early warnings could be issued that include information on what people can do to protect themselves and to protect crops and ecosystems," Ebi said.

Thriving reef fisheries continue to provide food despite coral bleaching

The unexpected results of a 20-year study into reef fisheries published in the journal Nature Ecology and Evolution this week showed fisheries being maintained despite extreme coral bleaching. Remarkably, the rapid proliferation of fishes with low dependence on corals led to catches remaining stable or even increasing. But the results also showed a fishing success was 'patchy' and more dependent on fewer species. Around six million people fish on coral reefs. Each year their catch -- estimated to be between 1.4 and 4.2 million tonnes -- provides a critical source of food and income for many millions more. But climate change-driven coral bleaching events, caused by warming seas, are damaging coral habitat and depleting fish biodiversity, which has sparked fears that these vibrant ecosystems will no longer support productive fisheries. A Lancaster University-led study set out to test this, using 20 years of fish abundance, catch and habitat data to assess the long-term impacts of climate-driven coral mass mortality and changes in artisanal coral reef fisheries in Seychelles. As part of their study, they looked at more than 45,000 daily fishery landing records from 41 different sites. They also conducted 960 underwater surveys at 12 locations. After the mass coral bleaching event in 1998, which caused substantial loss of coral habitat across Seychelles, reef fish catches have either remained the same and even increased. Although many reefs became overgrown with seaweeds, increases in algal-feeding fish communities such as rabbitfish are enabling local fishers to continue harvesting food. Dr. James Robinson of Lancaster University's Environment Centre said:

"Bleaching in 1998 caused mass coral mortality, habitat collapse, and shifts to seaweed dominance on some reefs, and so we expected the fishery to be in decline. But we overlooked the potential for algal-feeding fish to benefit from higher algal productivity." "With coral bleaching events becoming more frequent and more intense as the climate warms, the unexpected news was that these fisheries continued to provide benefits for people." Calvin Gerry of the Seychelles Fishing Authority, a co-author of the study, said: "We focussed on the inshore trap fishery in this study, as it is an important sector in Seychelles and a common gear on coral reefs globally." "Most of the fish from the trap fishery are sold and consumed locally, rather than exported internationally. Therefore, changes to this fishery have the potential to influence both fishers and consumers domestically." The study focused on short- and medium-term impacts of climate change. But the researchers have warned that these fisheries may be more unpredictable and variable than before because the fishes contributing to catches were much more patchily distributed. Declines in healthy coral habitat reduced the diversity of species in catches, and fishers were more reliant on a few highly productive rabbitfish species. Professor Nicholas Graham of Lancaster University, a co-author of the study, added: "Although we saw that after coral bleaching the average fish catch rose or remained stable, fishing success was patchy. After bleaching, catches became either much larger or much smaller than the average." "These data from Seychelles forewarn of changes likely for coral reef fisheries in other countries. While the news for fishers is better than we might expect, the algal-covered reefs are in marked contrast to the complex coral habitats which once hosted myriad and diverse coral reef fishes." While the rabbitfish boost was shown to give fishers a few years of respite from the effects of widespread coral bleaching, the authors caution that the longer-term outlook for reef fisheries remains uncertain. 

Growing pile of human and animal waste harbors threats, opportunities

Now researchers at Georgia Institute of Technology and the Centers for Disease Control and Prevention are highlighting another effect from animals raised for food and the humans who eat them: the waste they all leave behind. In a paper published November 13 in Nature Sustainability, the research team put forth what they believe is the first global estimate of annual recoverable human and animal fecal biomass. In 2014, the most recent year with data, the number was 4.3 billion tons and growing, and waste from livestock outweighed that from humans five to one at the country level. "Exposure to both human and animal waste represent a threat to public health, particularly in low-income areas of the world that may not have resources to implement the best management and sanitation practices," said Joe Brown, an assistant professor in Georgia Tech's School of Civil and Environmental Engineering. "But estimating the number of recoverable feces in the world also highlights the enormous potential from a resource perspective." Metals, phosphorus, nitrogen, and potassium are all among the resources that could be recovered from human and animal waste. The researchers pointed to an earlier analysis that estimated the value of recoverable metals alone reaches $13 million a year from the waste of one million people. The researchers looked at data from 2003 to 2014 as well as projections through 2030. The study combined global animal population data from the United Nations, human population data from the World Bank as well as earlier research on animal-specific estimates of fecal production. From 2003 to 2014, the amount of waste biomatter produced grew annually by more than 57 million tons as both human and livestock populations grew. The researchers estimated that by 2030, the total amount of global fecal biomass produced each year would reach at least five billion tons, with livestock waste outweighing that from humans six to one at the country level. "This paper demonstrates that building more latrines in developing parts of the world isn't going to solve all of our waste management problems," Brown said. "Animal waste has the potential to negatively impact health in many of the same ways as with human waste, from spreading enteric infections to hurting growth and cognitive development of the humans exposed." While chickens were the most plentiful livestock globally, cattle, with their larger body mass, produced the most fecal waste on the planet. As a result, countries with high numbers of cattle, such as those in the Americas, produced the most waste by mass. The researchers estimated that by 2030, the planet's total annual fecal and urinary biomass could contain as much as 100 million tons of phosphorus, 30 million tons of potassium, 18 million tons of calcium, and 5.5 million tons of magnesium, to name a few recoverable materials. While much of the attention on reducing disease transmission has focused through the decades on pathogens associated with human waste, much less attention has been given to animal waste, the researchers wrote, despite livestock accounting for 80 percent of the global fecal biomass generated. "Ultimately, shining a light on the amount of waste that we produce is the first step toward shaping policies and regional planning geared toward maximizing public health and resource recovery," Brown said. "This is an area where there's a huge need for attention and investment -- to help develop next-generation waste management innovations, for both large-scale and small-scale animal husbandry operations, that will enable us to maximize human health and meet the global demand for natural resources." As demand for meat and dairy products increases across the world, much attention has landed on how livestock impact the environment, from land usage to greenhouse gas emissions. Now researchers at Georgia Institute of Technology and the Centers for Disease Control and Prevention are highlighting another effect from animals raised for food and the humans who eat them: the waste they all leave behind. In a paper published November 13 in Nature Sustainability, the research team put forth what they believe is the first global estimate of annual recoverable human and animal fecal biomass. In 2014, the most recent year with data, the number was 4.3 billion tons and growing, and waste from livestock outweighed that from humans five to one at the country level.

Climate change and air pollution damaging health and causing millions of premature deaths

IIASA researchers have contributed to a major new report in The Lancet medical journal looking at the effects of climate change on human health, and the implications for society. The 2018 Report of the research coalition The Lancet Countdown: Tracking Progress on Health and Climate Change shows that rising temperatures as a result of climate change are already exposing us to an unacceptably high health risk and warns, for the first time, that older people in Europe and the East Mediterranean are particularly vulnerable to extremes of heat, markedly higher than in Africa and SE Asia. The risk in Europe and the Eastern Mediterranean stems from aging populations living in cities, with 42% and 43% of over-65s respectively vulnerable to heat. In Africa, 38% are thought to be vulnerable, while in Asia it is 34%. The report also states that ambient air pollution resulted in several million premature deaths from ambient fine particulate matter globally in 2015, a conclusion from IIASA researchers confirming earlier assessments. Since air pollution and greenhouse gases often share common sources, mitigating climate change constitutes a major opportunity for direct human health benefits. Leading doctors, academics and policy professionals from 27 organizations have contributed analysis and jointly authored the report. Alongside IIASA, the partners behind the research include the World Bank, World Health Organization (WHO), University College London and Tsinghua University, among others. IIASA researcher Gregor Kiesewetter led a team from the Air Pollution and Greenhouse Gase's research program that estimated the dangers of air pollution to human health. A new and important finding this year was the global attribution of deaths to a source. Kiesewetter and the team found that coal alone accounts for 16% of pollution-related premature deaths, around 460,000, which they state makes phasing out coal-use a "crucial no-regret intervention for public health." Kiesewetter and the team used the GAINS Model, developed at IIASA, which calculates the emissions of precursors of particulate matter based on a detailed breakdown of economic sectors and fuels used. Large contributions to ambient air pollution come from the residential sector, mostly from solid fuels like biomass and coal. Industry, electricity generation, transport, and agriculture are also important contributors. While coal should be a key target for early phase-out in households and electricity generation as it is highly polluting, it is not all that should be done. "The attribution shows that unfortunately, an approach targeting a single sector or fuel won't solve the problem -- air pollution is a multi-faceted issue that needs integrated strategies cutting across many sectors, which will differ from country to country. This is what we typically do with the regional and local GAINS model: giving advice to policymakers on the most effective approaches to tackle air pollution in their specific settings," says Kiesewetter.

The report contains a number of other headline findings: -

• 157m more vulnerable people were subjected to a heatwave in 2017 than in 2000, and 18m more than in 2016.
• 153bn hours of work were lost in 2017 due to extreme heat as a result of climate change. China alone lost 21bn hours, the equivalent of a year's work for 1.4% of their working population. India lost 75bn hours, equivalent to 7% of their total working population.
• Heat greatly exacerbates urban air pollution, with 97% of cities in low- and middle- income countries not meeting WHO air quality guidelines.
• Heat stress, an early and severe effect of climate change, is commonplace and we and the health systems we rely on are ill-equipped to cope.
• Rising temperatures and unseasonable warmth are responsible for cholera and dengue fever spreading, with vectorial capacity for their transmission increasing across many endemic areas.
• The mean global temperature change to which humans are exposed is more than double the global average change, with temperatures rising by 0.8°C versus 0.3°C.

Hugh Montgomery, co-chair of The Lancet Countdown on Health and Climate Change and director of the Institute for Human Health and Performance, University College London says: "Heat stress is hitting hard -- particularly amongst the urban elderly, and those with underlying health conditions such as cardiovascular disease, diabetes or chronic kidney disease. In high temperatures, outdoor work, especially in agriculture, is hazardous. Areas from Northern England and California, to Australia, are seeing savage fires with direct deaths, displacement, and loss of housing as well as respiratory impacts from smoke inhalation." The report, which looks at 41 separate indicators across a range of themes, says urgent steps are needed to protect people now from the impacts of climate change. In particular, stronger labor regulations are needed to protect workers from extremes of heat and hospitals and the health systems we rely on the need to be better equipped for extreme heat so they are able to cope. But the report also stresses that there are limits to adapting to the temperature increases, and if left unabated, climate change and heat will overwhelm even the strongest of systems, so the need for reducing greenhouse gas emissions is critical.

2018 has been an even hotter year in many parts of the world and the World Weather Attribution Study for northern Europe showed this summer's heat wave was twice as likely to have happened as a result of man-made climate change. Of the 478 global cities surveyed in the report, 51% expect climate change to seriously compromise their public health infrastructure.

"The world has yet to effectively cut its emissions. The speed of climate change threatens our, and our children's lives. Following current trends, we exhaust our carbon budget required to keep warming below two degrees, by 2032. The health impacts of climate change above this level above this level threaten to overwhelm our emergency and health services," says Anthony Costello, co-chair of The Lancet Countdown.

Other findings of the report include a new indicator mapping extremes of precipitation that identify South America and Southeast Asia among the regions most exposed to flood and drought and, on food security, the report points to 30 countries experiencing downward trends in crop yields, reversing a decade-long trend that had previously seen global improvement. Yield potential is estimated to be declining in every region as extremes of weather become more frequent and more extreme.

Greenhouse gas 'detergent' recycles itself in atmosphere

A simple molecule in the atmosphere that acts as a "detergent" to break down methane and other greenhouse gases has been found to recycle itself to maintain a steady global presence in the face of rising emissions, according to new NASA research. Understanding its role in the atmosphere is critical for determining the lifetime of methane, a powerful contributor to climate change. The hydroxyl (OH) radical, a molecule made up of one hydrogen atom, one oxygen atom with a free (or unpaired) electron is one of the most reactive gases in the atmosphere and regularly breaks down other gases, effectively ending their lifetimes. In this way, OH is the main check on the concentration of methane, a potent greenhouse gas that is second only to carbon dioxide in contributing to increasing global temperatures. With the rise of methane emissions into the atmosphere, scientists historically thought that might cause the number of hydroxyl radicals to be used upon the global scale and, as a result, extend methane's lifetime, currently estimated to be nine years. However, in addition to looking globally at primary sources of OH and the amount of methane and other gases it breaks down, this new research takes into account secondary OH sources, recycling that happens after OH breaks down methane and reforms in the presence of other gases, which has been observed on regional scales before. "OH concentrations are pretty stable over time," said atmospheric chemist and lead author Julie Nicely at NASA's Goddard Space Flight Center in Greenbelt, Maryland. "When OH reacts with methane it doesn't necessarily go away in the presence of other gases, especially nitrogen oxides (NO and NO₂). The breakdown products of its reaction with methane react with NO or NO₂ to reform OH. So OH can recycle back into the atmosphere." Nitrogen oxides are one set of several gases that contribute to recycling OH back into the atmosphere, according to Nicely's research, published in the Journal of Geophysical Research: Atmospheres. She and her colleagues used a computer model informed by satellite observations of various gases from 1980 to 2015 to simulate the possible sources for OH in the atmosphere. These include reactions with the aforementioned nitrogen oxides, water vapor, and ozone. They also tested an unusual potential source of new OH: the enlargement of the tropical regions on Earth. OH in the atmosphere also forms when ultraviolet sunlight reaches the lower atmosphere and reacts with water vapor (H₂O) and ozone (O₃) to form two OH molecules. Over the tropics, water vapor and ultraviolet sunlight are plentiful. The tropics, which span the region of Earth to either side of the equator, have shown some evidence of widening farther north and south of their current range, possibly due to rising temperatures affecting air circulation patterns. This means that the tropical region primed for creating OH will potentially increase over time, leading to a higher amount of OH in the atmosphere. This tropical widening process is slow, however, expanding only 0.5 to 1 degree in latitude every 10 years. But the small effect may still be important, according to Nicely. She and her team found that, individually, the tropical widening effect and OH recycling through reactions with other gases each comprise a relatively small source of OH, but together they essentially replace the OH used up in the breaking down of methane. "The absence of a trend in global OH is surprising," said atmospheric chemist Tom Hanisco at Goddard who was not involved in the research. "Most models predict a 'feedback effect' between OH and methane. In the reaction of OH with methane, OH is also removed. The increase in NO₂ and other sources of OH, such as ozone, cancel out this expected effect." But since this study looks at the past thirty-five years, it's not guaranteed that as the atmosphere continues to evolve with global climate change that OH levels will continue to recycle in the same way into the future, he said. Ultimately, Nicely views the results as a way to fine-tune and update the assumptions that are made by researchers and climate modelers who describe and predict how OH and methane interact throughout the atmosphere. "This could add clarification on the question of will methane concentrations continue rising in the future? Or will they level off, or perhaps even decrease? This is a major question regarding future climate that we really don't know the answer to," she said.

New catalyst produces cheap hydrogen fuel

Professor Anthony O'Mullane said the potential for the chemical storage of renewable energy in the form of hydrogen was being investigated around the world. "The Australian Government is interested in developing a hydrogen export industry to export our abundant renewable energy," said Professor O'Mullane from QUT's Science and Engineering Faculty. "In principle, hydrogen offers a way to store clean energy at a scale that is required to make the rollout of large-scale solar and wind farms as well as the export of green energy viable. "However, current methods that use carbon sources to produce hydrogen emit carbon dioxide, a greenhouse gas that mitigates the benefits of using renewable energy from the sun and wind. "Electrochemical water splitting driven by electricity sourced from renewable energy technology has been identified as one of the most sustainable methods of producing high-purity hydrogen." Professor O'Mullane said the new composite material he and Ph.D. student Ummul Sultana had developed enabled electrochemical water splitting into hydrogen and oxygen using cheap and readily available elements as catalysts. "Traditionally, catalysts for splitting water involve expensive precious metals such as iridium oxide, ruthenium oxide, and platinum," he said. "An additional problem has been stability, especially for the oxygen evolution part of the process. "What we have found is that we can use two earth-abundant cheaper alternatives -- cobalt and nickel oxide with only a fraction of gold nanoparticles -- to create a stable bi-functional catalyst to split water and produce hydrogen without emissions. "From an industry point of view, it makes a lot of sense to use one catalyst material instead of two different catalysts to produce hydrogen from water." Professor O'Mullane said the stored hydrogen could then be used in fuel cells. "Fuel cells are a mature technology, already being rolled out in many makes of vehicle. They use hydrogen and oxygen as fuels to generate electricity -- essentially the opposite of water splitting. "With a lot of cheaply 'made' hydrogen we can feed fuel cell-generated electricity back into the grid when required during peak demand or power our transportation system and the only thing emitted is water."