Tag Archives: Air pollution

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Where on Earth will the waste go?

FOR IMMEDIATE RELEASE As the world’s population continues to grow, so too the collective rubbish dump of human waste increases – and according to a recent report, it might not be until sometime next century that it begins to recede. LONDON, 2 November – Human waste production has multiplied tenfold in the last century. Rubbish – plastic bags, pizza boxes, empty beer cans, tinfoil, bubble wrap, old mattresses, rusty machinery, broken bottles, spent batteries, stale sandwiches, wilting salads and abandoned newsprint – is being generated faster than any other environmental pollutants, including greenhouse gases. And the problem will go on getting bigger until some time in the next century. Daniel Hoornweg of the University of Ontario and Chris Kennedy of the University of Toronto in Canada and Perinaz Bhada-Tata of Dubai in the United Arab Emirates argue in Nature that the combination of urban growth and material affluence is creating a throwaway problem that won’t go away. The average person in the US throws away his (or her) own body weight in rubbish every month. The detritus linked to modern living has not only grown tenfold in a century; by 2025 it will double again. Solid waste disposal has become one of any modern city’s biggest costs. Landfill sites near Shanghai, in Rio de Janeiro, and in Mexico City typically receive 10,000 tonnes of waste a day.  The world now has more than 2,000 waste incinerators, some able to burn 5,000 tonnes a day, creating attendant problems of ash and air-polluting fumes. Landfill waste is of course also a notorious source of methane – a potent greenhouse gas – but the authors are primarily concerned with the simple problems posed by the increasing volume of affluent society’s rejected stuff. It’s a city thing, they say. Country dwellers don’t buy so much packaged food, don’t have factories and don’t throw so much food away. City dwellers on average generate twice as much waste; the more affluent urbanites throw away four times as much. The three researchers – an expert in energy systems, a civil engineer and an urban waste consultant – say that in 1900 there were 220 million people in the cities. That was 13% of the planet’s population, and these townsfolk produced 300,000 tonnes of discarded stuff every day. By 2000, there were 2.9 billion people in cities – 49% of the world’s population – creating more than three million tonnes of solid waste per day. By 2025, it will be twice that = enough to fill a line of rubbish trucks 5,000 kilometres long every day.

International idiosyncrasies

Some countries are more profligate than others. Japan’s citizens produce about one third less, per person, than US citizens, even though the gross domestic product per capita is about the same. China’s solid waste generation is expected to go from 520,550 tonnes per day to 1.4 million by 2025. “As a country becomes richer, the composition of its waste changes,” the authors say. “With more money comes more packaging, imports, electronic waste and broken toys and appliances. The wealth of a country can readily be measured, for example, by how many mobile phones it discards.” Hoornweg and Bhada-Tata are the authors of a 2012 World Bank report in which they projected a world dustbin collection of 6 million tonnes a day by 2025. They calculate that under a business-as-usual scenario waste will grow with population and affluence as the century wears on, with increasing growth in South Asia and sub-Saharan Africa, and by 2100 it will exceed 11 million tonnes a day and peak sometime in the next century. But this scenario is not inevitable. “With lower populations, denser, more resource-efficient cities and less consumption (along with higher affluence) the peak could come forward to 2075 and reduce in intensity by more than 25%,” they say. This would save around 2.6 million tonnes per day. – Climate News Network

FOR IMMEDIATE RELEASE As the world’s population continues to grow, so too the collective rubbish dump of human waste increases – and according to a recent report, it might not be until sometime next century that it begins to recede. LONDON, 2 November – Human waste production has multiplied tenfold in the last century. Rubbish – plastic bags, pizza boxes, empty beer cans, tinfoil, bubble wrap, old mattresses, rusty machinery, broken bottles, spent batteries, stale sandwiches, wilting salads and abandoned newsprint – is being generated faster than any other environmental pollutants, including greenhouse gases. And the problem will go on getting bigger until some time in the next century. Daniel Hoornweg of the University of Ontario and Chris Kennedy of the University of Toronto in Canada and Perinaz Bhada-Tata of Dubai in the United Arab Emirates argue in Nature that the combination of urban growth and material affluence is creating a throwaway problem that won’t go away. The average person in the US throws away his (or her) own body weight in rubbish every month. The detritus linked to modern living has not only grown tenfold in a century; by 2025 it will double again. Solid waste disposal has become one of any modern city’s biggest costs. Landfill sites near Shanghai, in Rio de Janeiro, and in Mexico City typically receive 10,000 tonnes of waste a day.  The world now has more than 2,000 waste incinerators, some able to burn 5,000 tonnes a day, creating attendant problems of ash and air-polluting fumes. Landfill waste is of course also a notorious source of methane – a potent greenhouse gas – but the authors are primarily concerned with the simple problems posed by the increasing volume of affluent society’s rejected stuff. It’s a city thing, they say. Country dwellers don’t buy so much packaged food, don’t have factories and don’t throw so much food away. City dwellers on average generate twice as much waste; the more affluent urbanites throw away four times as much. The three researchers – an expert in energy systems, a civil engineer and an urban waste consultant – say that in 1900 there were 220 million people in the cities. That was 13% of the planet’s population, and these townsfolk produced 300,000 tonnes of discarded stuff every day. By 2000, there were 2.9 billion people in cities – 49% of the world’s population – creating more than three million tonnes of solid waste per day. By 2025, it will be twice that = enough to fill a line of rubbish trucks 5,000 kilometres long every day.

International idiosyncrasies

Some countries are more profligate than others. Japan’s citizens produce about one third less, per person, than US citizens, even though the gross domestic product per capita is about the same. China’s solid waste generation is expected to go from 520,550 tonnes per day to 1.4 million by 2025. “As a country becomes richer, the composition of its waste changes,” the authors say. “With more money comes more packaging, imports, electronic waste and broken toys and appliances. The wealth of a country can readily be measured, for example, by how many mobile phones it discards.” Hoornweg and Bhada-Tata are the authors of a 2012 World Bank report in which they projected a world dustbin collection of 6 million tonnes a day by 2025. They calculate that under a business-as-usual scenario waste will grow with population and affluence as the century wears on, with increasing growth in South Asia and sub-Saharan Africa, and by 2100 it will exceed 11 million tonnes a day and peak sometime in the next century. But this scenario is not inevitable. “With lower populations, denser, more resource-efficient cities and less consumption (along with higher affluence) the peak could come forward to 2075 and reduce in intensity by more than 25%,” they say. This would save around 2.6 million tonnes per day. – Climate News Network

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Plants wilt as heat increases ozone

FOR IMMEDIATE RELEASE Plants are significantly less able to absorb low-level ozone during a heatwave, researchers have found, with implications for human health. LONDON, 20 July – Rising temperatures could be bad news for people with bad lungs. Two new lines of research are bleak reminders of the link between air quality and human health. A study from the University of York in the UK reports that ozone levels soar during heat waves – perhaps because the capacity of plants to absorb ozone is curtailed as the mercury goes up. When the ground is dry and the temperatures rise, plants become stressed: they shut their stomata – those tiny pores in their leaves – to conserve moisture. It means they can survive the high ozone levels that tend to follow traffic fumes and factory exhausts in hot weather.  But it also means they cannot react to the ozone. “Vegetation can absorb as much as 20% of the global atmospheric ozone production, so the potential impact on air quality is substantial”, said Dr Lisa Emberson of the university’s Stockholm Environment Institute. She and colleagues report in the journal Atmospheric Chemistry and Physics that they studied the European heat wave of June and July 2006, and modelled the hazard to human health under conditions of both perfect and minimal ozone absorption. They calculate that the extra ozone not absorbed by plants during the heat wave – and for 16 days, levels of ozone would have been above the threshold for human safety – accounted for 460 extra deaths in the UK.

Acute effect on south-east Asia

Ozone in the stratosphere is vital to human health: it screens out dangerous wavelengths of ultraviolet light. Ozone in the lower atmosphere though is a toxin, and a dangerous irritant that can lead to increased asthma attacks and lung inflammation. Pinning individual deaths to this or that environmental cause is very difficult, but using statistical logic, epidemiologists have been comfortably calculating notional extra deaths because of air pollution for decades. Worldwide, according to a report in Environmental Research Letters, more than two million people die because of human-caused outdoor air pollution. Researchers report that, so far, climate change has had only a minimal effect on death rates. Around 470,000 people die each year because of ozone pollution, and around 2.1 million deaths are caused by fine particulate matter – tiny particles that become trapped in the lungs. Once again, the research is based on climate model simulations. Jason West of the University of North Carolina, US, one of the authors, said: “Our estimates make outdoor air pollution among the most important environmental risk factors for health. Many of these deaths are estimated to occur in East Asia and South Asia, where population is high and air pollution is severe.” – Climate News Network

FOR IMMEDIATE RELEASE Plants are significantly less able to absorb low-level ozone during a heatwave, researchers have found, with implications for human health. LONDON, 20 July – Rising temperatures could be bad news for people with bad lungs. Two new lines of research are bleak reminders of the link between air quality and human health. A study from the University of York in the UK reports that ozone levels soar during heat waves – perhaps because the capacity of plants to absorb ozone is curtailed as the mercury goes up. When the ground is dry and the temperatures rise, plants become stressed: they shut their stomata – those tiny pores in their leaves – to conserve moisture. It means they can survive the high ozone levels that tend to follow traffic fumes and factory exhausts in hot weather.  But it also means they cannot react to the ozone. “Vegetation can absorb as much as 20% of the global atmospheric ozone production, so the potential impact on air quality is substantial”, said Dr Lisa Emberson of the university’s Stockholm Environment Institute. She and colleagues report in the journal Atmospheric Chemistry and Physics that they studied the European heat wave of June and July 2006, and modelled the hazard to human health under conditions of both perfect and minimal ozone absorption. They calculate that the extra ozone not absorbed by plants during the heat wave – and for 16 days, levels of ozone would have been above the threshold for human safety – accounted for 460 extra deaths in the UK.

Acute effect on south-east Asia

Ozone in the stratosphere is vital to human health: it screens out dangerous wavelengths of ultraviolet light. Ozone in the lower atmosphere though is a toxin, and a dangerous irritant that can lead to increased asthma attacks and lung inflammation. Pinning individual deaths to this or that environmental cause is very difficult, but using statistical logic, epidemiologists have been comfortably calculating notional extra deaths because of air pollution for decades. Worldwide, according to a report in Environmental Research Letters, more than two million people die because of human-caused outdoor air pollution. Researchers report that, so far, climate change has had only a minimal effect on death rates. Around 470,000 people die each year because of ozone pollution, and around 2.1 million deaths are caused by fine particulate matter – tiny particles that become trapped in the lungs. Once again, the research is based on climate model simulations. Jason West of the University of North Carolina, US, one of the authors, said: “Our estimates make outdoor air pollution among the most important environmental risk factors for health. Many of these deaths are estimated to occur in East Asia and South Asia, where population is high and air pollution is severe.” – Climate News Network

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Pollution in the north shrank Lake Chad

FOR IMMEDIATE RELEASE The bad habits of the locals have been blamed for the decline of Lake Chad in Africa but it was pollution from people far away that caused rain patterns to shift. LONDON, 16 June – American scientists have a new explanation for one of the great ecological disasters of the 1980s. The alarming near-disappearance of Lake Chad – a giant body of water that nourished crops in the Sahel region – was, they say, caused by air pollution: old-fashioned smog and soot from factory chimneys and coal-burning power plants in Europe and America. The initial explanation had been a much simpler one, and pinned the guilt on the locals. Lake Chad, which extended over 25,000 square kilometres in the 1960s, shrank to a 20th of its former area by the end of the last century, all because of overgrazing and too great a demand for water for irrigation, geographers had once argued. The consequences for the local peoples of Nigeria, Chad, Cameroon and Niger were devastating, and triggered global concern, especially as the summer rains repeatedly failed and the lake was not seasonally replenished. Another culprit Later, Lake Chad became an awful example of the possible consequences of global warming. In the latest twist in the story, scientists at the University of Washington in the US have pointed to another culprit: the sulphate aerosol. Aerosols pumped from chimneys and exhaust pipes in the developed world scattered in the atmosphere and reflected sunlight back into space, to cool the entire northern hemisphere, the region with the greatest land mass, the highest economic development and the most factory chimneys. In response to a small change in overall conditions the tropical rain belt shifted southwards with a steady decrease in precipitation in the Sahel from the 1950s onward. The lowest ever recorded rainfall in the region was during the early 1980s, “perhaps the most striking precipitation change in the 20th century observational record,” say Yen-Ting Hwang and colleagues in Geophysical Research Letters. In fact, the authors are careful to say this is “in part” an explanation of the drought in the Sahel: complex natural changes have complex causes, and both global climate change and pressure from human population growth remain implicated. Hwang’s study used six decades of continuous data from rain gauges to link the drought to a global shift in tropical rainfall, and then used 26 different climate models to make the link between hemisphere temperatures and the pattern of rainfall. The Sahel was not the only region affected: northern India and parts of South America experienced drier decades, while places at the southern edge of the tropical rain belt, such as north-east Brazil and the African Great Lakes, were wetter than normal. Rain shifts again As clean air legislation passed both in the US and Europe slowly cleared the skies, the northern hemisphere began to warm faster than the southern hemisphere, and the tropical rain belt began to shift north again. A team at the University of California, Berkeley, in April reported in the Journal of Climate, published by the American Meteorological Society, that temperature differences measured over a century coincided with changes in the pattern of tropical rainfall. The largest difference – a drop of about half a degree Celsius in the northern hemisphere in the late 1960s, coincided with a 30-year drought in the Sahel, the growth of the deserts in the Sahara and the failures of the monsoons in India and east Asia. The research is a reminder that climate patterns are sensitive to even very small average shifts in temperature on a very large scale; that what happens in one region can quite dramatically affect conditions in another part of the globe; and that human actions in some of the richest regions of the planet can have cruel consequences for those trying to make a living in the poorest places. Meanwhile, although the rains have returned, Lake Chad is still very much diminished. – Climate News Network

FOR IMMEDIATE RELEASE The bad habits of the locals have been blamed for the decline of Lake Chad in Africa but it was pollution from people far away that caused rain patterns to shift. LONDON, 16 June – American scientists have a new explanation for one of the great ecological disasters of the 1980s. The alarming near-disappearance of Lake Chad – a giant body of water that nourished crops in the Sahel region – was, they say, caused by air pollution: old-fashioned smog and soot from factory chimneys and coal-burning power plants in Europe and America. The initial explanation had been a much simpler one, and pinned the guilt on the locals. Lake Chad, which extended over 25,000 square kilometres in the 1960s, shrank to a 20th of its former area by the end of the last century, all because of overgrazing and too great a demand for water for irrigation, geographers had once argued. The consequences for the local peoples of Nigeria, Chad, Cameroon and Niger were devastating, and triggered global concern, especially as the summer rains repeatedly failed and the lake was not seasonally replenished. Another culprit Later, Lake Chad became an awful example of the possible consequences of global warming. In the latest twist in the story, scientists at the University of Washington in the US have pointed to another culprit: the sulphate aerosol. Aerosols pumped from chimneys and exhaust pipes in the developed world scattered in the atmosphere and reflected sunlight back into space, to cool the entire northern hemisphere, the region with the greatest land mass, the highest economic development and the most factory chimneys. In response to a small change in overall conditions the tropical rain belt shifted southwards with a steady decrease in precipitation in the Sahel from the 1950s onward. The lowest ever recorded rainfall in the region was during the early 1980s, “perhaps the most striking precipitation change in the 20th century observational record,” say Yen-Ting Hwang and colleagues in Geophysical Research Letters. In fact, the authors are careful to say this is “in part” an explanation of the drought in the Sahel: complex natural changes have complex causes, and both global climate change and pressure from human population growth remain implicated. Hwang’s study used six decades of continuous data from rain gauges to link the drought to a global shift in tropical rainfall, and then used 26 different climate models to make the link between hemisphere temperatures and the pattern of rainfall. The Sahel was not the only region affected: northern India and parts of South America experienced drier decades, while places at the southern edge of the tropical rain belt, such as north-east Brazil and the African Great Lakes, were wetter than normal. Rain shifts again As clean air legislation passed both in the US and Europe slowly cleared the skies, the northern hemisphere began to warm faster than the southern hemisphere, and the tropical rain belt began to shift north again. A team at the University of California, Berkeley, in April reported in the Journal of Climate, published by the American Meteorological Society, that temperature differences measured over a century coincided with changes in the pattern of tropical rainfall. The largest difference – a drop of about half a degree Celsius in the northern hemisphere in the late 1960s, coincided with a 30-year drought in the Sahel, the growth of the deserts in the Sahara and the failures of the monsoons in India and east Asia. The research is a reminder that climate patterns are sensitive to even very small average shifts in temperature on a very large scale; that what happens in one region can quite dramatically affect conditions in another part of the globe; and that human actions in some of the richest regions of the planet can have cruel consequences for those trying to make a living in the poorest places. Meanwhile, although the rains have returned, Lake Chad is still very much diminished. – Climate News Network

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Soot fingered as climate threat

FOR IMMEDIATE RELEASE A study has found that black carbon, often called soot, is damaging the climate more than researchers had realised, and that cutting emissions could help to lower global temperatures. LONDON, 16 January – Climate scientists have just conceded that they may have been wrong about one aspect of man-made climate change – they have underestimated the dangerous impact of fumes from diesel exhausts and other sources of soot. Black carbon, as soot is also known, could be twice as bad as previously estimated as an agent of global warming. The news comes in an exhaustive, 232-page study published in the Journal of Geophysical Research – Atmospheres, written by 31 scientists from the US, Europe, Japan, China and India. They calculate that, in various ways, black carbon has a warming effect of 1.1 watts per square metre. This makes it two-thirds as influential as the principal man-made greenhouse gas, carbon dioxide. So the second biggest contributor to the global atmospheric crisis is soot. Soot has, say the scientists of the International Global Atmospheric Chemistry Project, “a unique combination of physical properties.” It strongly absorbs visible light, it is insoluble in water and it sticks around for a long time. It comes from the burning of coal and wood and dung in Africa and Asia, while diesel engines provide most of the black carbon in the air above Europe, North America and Latin America. The researchers reckon that 7.5 million tonnes a year of black carbon could be dumped in the atmosphere from power stations, cooking stoves, diesel engines and forest fires, although they also concede that total emissions are difficult to measure precisely. Black carbon was blamed for a sudden, dramatic melting of Greenland’s ice in the summer of 2012: the source of the soot was wildfires in the Arctic tundra.

“…we need to tackle air pollution and climate change as one joined-up problem.”

The research is a reminder that alarm about atmospheric pollution by human action is not new: soot was a component of notorious urban smog that ultimately claimed hundreds of thousands of lives in the great European cities each year before the introduction of clean air legislation. According to the World Health Organisation, the smoke just from cooking stoves in the developing world probably contributes to two million deaths from respiratory diseases every year. So there have always been reasons for worrying about black carbon.  But its role as a component of global warming has not been seriously and publicly addressed until now. The tiny spheres of dark carbon absorb the heat from the sun, can affect cloud formation, and smear and darken the surface of snow and ice, to accelerate warming and melting. Black carbon is now seen as a significant cause of rapid warming in the mid- to high latitudes of the northern hemisphere, but it can also trigger changes in the patterns of monsoon rainfall in the tropics. So the reduction of emissions could reduce both the risk of respiratory diseases and the rate of climate change in a large region of the globe. “If we did everything we could to reduce these emissions we could buy ourselves up to half a degree (Celsius) less warming – or a couple of decades of respite,” said Piers Forster of the University of Leeds in the UK, one of the co-authors. But, he warned, the solution was not straightforward: black carbon is not the only product from fire, and some discharges from burning vegetation might instead have a cooling effect. Alastair Lewis, an atmospheric chemist at the University of York, UK, who is not one of the research team, said: “This new study helps us see the bigger picture: that we need to tackle air pollution and climate change as one joined-up problem.” – Climate News Network

FOR IMMEDIATE RELEASE A study has found that black carbon, often called soot, is damaging the climate more than researchers had realised, and that cutting emissions could help to lower global temperatures. LONDON, 16 January – Climate scientists have just conceded that they may have been wrong about one aspect of man-made climate change – they have underestimated the dangerous impact of fumes from diesel exhausts and other sources of soot. Black carbon, as soot is also known, could be twice as bad as previously estimated as an agent of global warming. The news comes in an exhaustive, 232-page study published in the Journal of Geophysical Research – Atmospheres, written by 31 scientists from the US, Europe, Japan, China and India. They calculate that, in various ways, black carbon has a warming effect of 1.1 watts per square metre. This makes it two-thirds as influential as the principal man-made greenhouse gas, carbon dioxide. So the second biggest contributor to the global atmospheric crisis is soot. Soot has, say the scientists of the International Global Atmospheric Chemistry Project, “a unique combination of physical properties.” It strongly absorbs visible light, it is insoluble in water and it sticks around for a long time. It comes from the burning of coal and wood and dung in Africa and Asia, while diesel engines provide most of the black carbon in the air above Europe, North America and Latin America. The researchers reckon that 7.5 million tonnes a year of black carbon could be dumped in the atmosphere from power stations, cooking stoves, diesel engines and forest fires, although they also concede that total emissions are difficult to measure precisely. Black carbon was blamed for a sudden, dramatic melting of Greenland’s ice in the summer of 2012: the source of the soot was wildfires in the Arctic tundra.

“…we need to tackle air pollution and climate change as one joined-up problem.”

The research is a reminder that alarm about atmospheric pollution by human action is not new: soot was a component of notorious urban smog that ultimately claimed hundreds of thousands of lives in the great European cities each year before the introduction of clean air legislation. According to the World Health Organisation, the smoke just from cooking stoves in the developing world probably contributes to two million deaths from respiratory diseases every year. So there have always been reasons for worrying about black carbon.  But its role as a component of global warming has not been seriously and publicly addressed until now. The tiny spheres of dark carbon absorb the heat from the sun, can affect cloud formation, and smear and darken the surface of snow and ice, to accelerate warming and melting. Black carbon is now seen as a significant cause of rapid warming in the mid- to high latitudes of the northern hemisphere, but it can also trigger changes in the patterns of monsoon rainfall in the tropics. So the reduction of emissions could reduce both the risk of respiratory diseases and the rate of climate change in a large region of the globe. “If we did everything we could to reduce these emissions we could buy ourselves up to half a degree (Celsius) less warming – or a couple of decades of respite,” said Piers Forster of the University of Leeds in the UK, one of the co-authors. But, he warned, the solution was not straightforward: black carbon is not the only product from fire, and some discharges from burning vegetation might instead have a cooling effect. Alastair Lewis, an atmospheric chemist at the University of York, UK, who is not one of the research team, said: “This new study helps us see the bigger picture: that we need to tackle air pollution and climate change as one joined-up problem.” – Climate News Network