Tag Archives: Sahel

Climate hotspots imperil parts of Africa

FOR IMMEDIATE RELEASE Three distinct parts of Africa which are likely to face the most severe impacts of climate change have been identified by researchers in Germany. LONDON, 6 May –  We know that the effects of climate change are going to be felt unequally around the world. How useful it would be to know where the greatest risks will occur. Now, for what they say is the first time, scientists in Germany have identified three African regions which they think should prepare for multiple problems in about 20 years’ time. They are in north-east Africa, central Africa and the south-east of the continent. The scientists, from the Potsdam Institute for Climate Impact Research (PIK), report their findings in a study published online in the journal Global Change Biology. The lead author, Christoph Müller, says: “We tried to identify the places where climate change really hurts most.” The three regions expected to be among those most at risk in a couple of decades are parts of Sudan and Ethiopia; the countries surrounding Lake Victoria in central Africa; and the continent’s south-eastern corner, especially parts of South Africa, Mozambique and Zimbabwe. They are expected to see more severe dry seasons and reduced plant growth, with flooding near Lake Victoria. The three are the sub-Saharan Africa regions where by 2100 there will be a high likelihood of possibly severe climatic impacts affecting countries with relatively high populations and high poverty rates.

Good news too

The authors say that overlapping impacts of climate change – drought, for example, floods, declining crop yields or ecosystem damage – create “hotspots of risk”. They believe their approach builds a more comprehensive picture of risk. Till now, they say, most studies have addressed only one aspect of climate change impacts at a time, even though multiple stresses amplify vulnerability. As well as identifying hotspots, they say their composite picture explicitly addresses the issue of uncertainty. They acknowledge there will be uncertainties in assessing the impacts. But they think these can in fact inform development strategies, allowing an assessment of the impacts’ likelihood and potential severity, and a choice of ways to adapt. And they say there is a clear upside to their work. “The good news is that large countries such as Nigeria and the tropical forests of the Congo region are likely to be much less affected,” Müller said. “It’s all about risks,” says Hermann Lotze-Campen, co-chair of PIK’s research domain Climate Impacts and Vulnerability. “We have to live with uncertainties: we don’t have perfect data about future impacts of climate change, but computer simulations can help to understand likelihoods and possible impacts.”

Ways to adapt

Likely impacts, such as more intensive spells of drought in the southern Sahel, clearly demand the development of coping strategies for farmers and pastoralists, the study says, even if it remains uncertain how intense this change will be. It recommends possible ways of adapting to risks. These include improved access to international agricultural markets, for instance, allowing herders to sell cattle before droughts, and insurance systems to balance increased variability in crop yields from one year to another, or water storage systems such as underground cisterns. “This study provides the people on the ground with information they can hopefully use to then decide what to do,” says Lotze-Campen. “A continental scenario analysis like this can never be a blueprint for adaptation, as it lacks local expertise. Yet it can help to decide where best to put limited resources in countries most affected by climate change.” – Climate News Network

FOR IMMEDIATE RELEASE Three distinct parts of Africa which are likely to face the most severe impacts of climate change have been identified by researchers in Germany. LONDON, 6 May –  We know that the effects of climate change are going to be felt unequally around the world. How useful it would be to know where the greatest risks will occur. Now, for what they say is the first time, scientists in Germany have identified three African regions which they think should prepare for multiple problems in about 20 years’ time. They are in north-east Africa, central Africa and the south-east of the continent. The scientists, from the Potsdam Institute for Climate Impact Research (PIK), report their findings in a study published online in the journal Global Change Biology. The lead author, Christoph Müller, says: “We tried to identify the places where climate change really hurts most.” The three regions expected to be among those most at risk in a couple of decades are parts of Sudan and Ethiopia; the countries surrounding Lake Victoria in central Africa; and the continent’s south-eastern corner, especially parts of South Africa, Mozambique and Zimbabwe. They are expected to see more severe dry seasons and reduced plant growth, with flooding near Lake Victoria. The three are the sub-Saharan Africa regions where by 2100 there will be a high likelihood of possibly severe climatic impacts affecting countries with relatively high populations and high poverty rates.

Good news too

The authors say that overlapping impacts of climate change – drought, for example, floods, declining crop yields or ecosystem damage – create “hotspots of risk”. They believe their approach builds a more comprehensive picture of risk. Till now, they say, most studies have addressed only one aspect of climate change impacts at a time, even though multiple stresses amplify vulnerability. As well as identifying hotspots, they say their composite picture explicitly addresses the issue of uncertainty. They acknowledge there will be uncertainties in assessing the impacts. But they think these can in fact inform development strategies, allowing an assessment of the impacts’ likelihood and potential severity, and a choice of ways to adapt. And they say there is a clear upside to their work. “The good news is that large countries such as Nigeria and the tropical forests of the Congo region are likely to be much less affected,” Müller said. “It’s all about risks,” says Hermann Lotze-Campen, co-chair of PIK’s research domain Climate Impacts and Vulnerability. “We have to live with uncertainties: we don’t have perfect data about future impacts of climate change, but computer simulations can help to understand likelihoods and possible impacts.”

Ways to adapt

Likely impacts, such as more intensive spells of drought in the southern Sahel, clearly demand the development of coping strategies for farmers and pastoralists, the study says, even if it remains uncertain how intense this change will be. It recommends possible ways of adapting to risks. These include improved access to international agricultural markets, for instance, allowing herders to sell cattle before droughts, and insurance systems to balance increased variability in crop yields from one year to another, or water storage systems such as underground cisterns. “This study provides the people on the ground with information they can hopefully use to then decide what to do,” says Lotze-Campen. “A continental scenario analysis like this can never be a blueprint for adaptation, as it lacks local expertise. Yet it can help to decide where best to put limited resources in countries most affected by climate change.” – Climate News Network

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

Geo-engineering 'could imperil Sahel'

EMBARGOED until 1700 GMT on Sunday 31 March
Attempts to tackle climate change by altering the atmosphere – geo-engineering – may have unpredictable effects. They could even trigger disaster in a drought-prone region of Africa, a study suggests.

LONDON, 31 March – Less than three weeks after two US researchers called for global agreement on the governance of geo-engineering research, British meteorologists have provided a case study in potential geo-engineering disaster.

Jim Haywood from the Met Office Hadley Centre and colleagues report in Nature Climate Change that fine particles concentrated in the stratosphere could precipitate calamitous drought in the Sahel region of Africa.

The team analysed historical observations from 1900 to 2010 and found that substantial volcanic eruptions in the Northern hemisphere – substantial enough to lift huge clouds of aerosols into the upper atmosphere – preceded three of the four driest summers in the region.

Furious volcanic blasts have been historically associated with climate change: an eruption of Mt Tambora in what is now Indonesia in 1815 was followed by Europe’s notorious “year without a summer” in 1816, along with widespread harvest failure, famine and outbreaks of disease.

The eruption of Mt Pinatubo in 1991 was followed by what climate scientists were later to call “the Pinatubo effect” – noticeable global cooling in the following years.

But what concerns Professor Haywood and others is not the random nature of volcanic eruption – difficult to predict and impossible to prevent – but the possibility of deliberate injection of aerosols into the stratosphere to moderate global warming.

The Sahel is the name given to a 1,000-kilometre band of savannah in Africa south of the Sahara, stretching from Mauretania in the west to Eritrea on the Red Sea coast.

The four driest periods in this relatively arid region – these periods bear the deadpan scientific label of negative Sahelian precipitation anomalies – were in 1913, 1972, 1983 and 1984. Three of these dry spells followed an eruption of Katmai in Alaska in 1912 and of El Chichon in Mexico in 1982.

“…a global governance agreement for geo-engineering is essential before any practical geo-engineering system is deployed…”

The extended drought between 1970 and 1990 in the Sahel region claimed 250,000 lives and created 10 million refugees: it was one of the world’s biggest humanitarian disasters.

All kinds of causes were evoked, including overgrazing, natural variability and industrial exhausts, but Professor Haywood and his colleagues think that volcanic eruptions also strongly influence the sea temperatures in the Atlantic, which are associated with Sahelian drought.

Their conclusions are provisional. Such associations are difficult to prove conclusively. They concede in their paper that “correlation does not prove causality and the sparsity of significant hemispherically asymmetric volcanic eruptions in the recent historical record hampers definitive attribution.” In other words, the jury is still out.

They simulated the impact of continued global warming into the future and found that – provided there was no geoengineering – only 11 of the 50 years between 2020 and 2070 would have negative Sahelian precipitation anomalies. Deliberate geoengineering, however, by loading aerosols into the northern hemisphere stratosphere would cause Sahelian drought.

This could possibly be countered by injecting particles into the southern hemisphere stratosphere, which might have the effect of increasing rainfall in the Sahel countries. But any good there might be countered by a consequent failure of the rains in north-east Brazil.

“Clearly, the juxtaposition of impacts leads us to believe that a global governance agreement for geo-engineering is essential before any practical geo-engineering system is deployed, and much further research is needed,” they conclude. – Climate News Network

EMBARGOED until 1700 GMT on Sunday 31 March
Attempts to tackle climate change by altering the atmosphere – geo-engineering – may have unpredictable effects. They could even trigger disaster in a drought-prone region of Africa, a study suggests.

LONDON, 31 March – Less than three weeks after two US researchers called for global agreement on the governance of geo-engineering research, British meteorologists have provided a case study in potential geo-engineering disaster.

Jim Haywood from the Met Office Hadley Centre and colleagues report in Nature Climate Change that fine particles concentrated in the stratosphere could precipitate calamitous drought in the Sahel region of Africa.

The team analysed historical observations from 1900 to 2010 and found that substantial volcanic eruptions in the Northern hemisphere – substantial enough to lift huge clouds of aerosols into the upper atmosphere – preceded three of the four driest summers in the region.

Furious volcanic blasts have been historically associated with climate change: an eruption of Mt Tambora in what is now Indonesia in 1815 was followed by Europe’s notorious “year without a summer” in 1816, along with widespread harvest failure, famine and outbreaks of disease.

The eruption of Mt Pinatubo in 1991 was followed by what climate scientists were later to call “the Pinatubo effect” – noticeable global cooling in the following years.

But what concerns Professor Haywood and others is not the random nature of volcanic eruption – difficult to predict and impossible to prevent – but the possibility of deliberate injection of aerosols into the stratosphere to moderate global warming.

The Sahel is the name given to a 1,000-kilometre band of savannah in Africa south of the Sahara, stretching from Mauretania in the west to Eritrea on the Red Sea coast.

The four driest periods in this relatively arid region – these periods bear the deadpan scientific label of negative Sahelian precipitation anomalies – were in 1913, 1972, 1983 and 1984. Three of these dry spells followed an eruption of Katmai in Alaska in 1912 and of El Chichon in Mexico in 1982.

“…a global governance agreement for geo-engineering is essential before any practical geo-engineering system is deployed…”

The extended drought between 1970 and 1990 in the Sahel region claimed 250,000 lives and created 10 million refugees: it was one of the world’s biggest humanitarian disasters.

All kinds of causes were evoked, including overgrazing, natural variability and industrial exhausts, but Professor Haywood and his colleagues think that volcanic eruptions also strongly influence the sea temperatures in the Atlantic, which are associated with Sahelian drought.

Their conclusions are provisional. Such associations are difficult to prove conclusively. They concede in their paper that “correlation does not prove causality and the sparsity of significant hemispherically asymmetric volcanic eruptions in the recent historical record hampers definitive attribution.” In other words, the jury is still out.

They simulated the impact of continued global warming into the future and found that – provided there was no geoengineering – only 11 of the 50 years between 2020 and 2070 would have negative Sahelian precipitation anomalies. Deliberate geoengineering, however, by loading aerosols into the northern hemisphere stratosphere would cause Sahelian drought.

This could possibly be countered by injecting particles into the southern hemisphere stratosphere, which might have the effect of increasing rainfall in the Sahel countries. But any good there might be countered by a consequent failure of the rains in north-east Brazil.

“Clearly, the juxtaposition of impacts leads us to believe that a global governance agreement for geo-engineering is essential before any practical geo-engineering system is deployed, and much further research is needed,” they conclude. – Climate News Network

Geo-engineering ‘could imperil Sahel’

EMBARGOED until 1700 GMT on Sunday 31 March Attempts to tackle climate change by altering the atmosphere – geo-engineering – may have unpredictable effects. They could even trigger disaster in a drought-prone region of Africa, a study suggests. LONDON, 31 March – Less than three weeks after two US researchers called for global agreement on the governance of geo-engineering research, British meteorologists have provided a case study in potential geo-engineering disaster. Jim Haywood from the Met Office Hadley Centre and colleagues report in Nature Climate Change that fine particles concentrated in the stratosphere could precipitate calamitous drought in the Sahel region of Africa. The team analysed historical observations from 1900 to 2010 and found that substantial volcanic eruptions in the Northern hemisphere – substantial enough to lift huge clouds of aerosols into the upper atmosphere – preceded three of the four driest summers in the region. Furious volcanic blasts have been historically associated with climate change: an eruption of Mt Tambora in what is now Indonesia in 1815 was followed by Europe’s notorious “year without a summer” in 1816, along with widespread harvest failure, famine and outbreaks of disease. The eruption of Mt Pinatubo in 1991 was followed by what climate scientists were later to call “the Pinatubo effect” – noticeable global cooling in the following years. But what concerns Professor Haywood and others is not the random nature of volcanic eruption – difficult to predict and impossible to prevent – but the possibility of deliberate injection of aerosols into the stratosphere to moderate global warming. The Sahel is the name given to a 1,000-kilometre band of savannah in Africa south of the Sahara, stretching from Mauretania in the west to Eritrea on the Red Sea coast. The four driest periods in this relatively arid region – these periods bear the deadpan scientific label of negative Sahelian precipitation anomalies – were in 1913, 1972, 1983 and 1984. Three of these dry spells followed an eruption of Katmai in Alaska in 1912 and of El Chichon in Mexico in 1982.

“…a global governance agreement for geo-engineering is essential before any practical geo-engineering system is deployed…”

The extended drought between 1970 and 1990 in the Sahel region claimed 250,000 lives and created 10 million refugees: it was one of the world’s biggest humanitarian disasters. All kinds of causes were evoked, including overgrazing, natural variability and industrial exhausts, but Professor Haywood and his colleagues think that volcanic eruptions also strongly influence the sea temperatures in the Atlantic, which are associated with Sahelian drought. Their conclusions are provisional. Such associations are difficult to prove conclusively. They concede in their paper that “correlation does not prove causality and the sparsity of significant hemispherically asymmetric volcanic eruptions in the recent historical record hampers definitive attribution.” In other words, the jury is still out. They simulated the impact of continued global warming into the future and found that – provided there was no geoengineering – only 11 of the 50 years between 2020 and 2070 would have negative Sahelian precipitation anomalies. Deliberate geoengineering, however, by loading aerosols into the northern hemisphere stratosphere would cause Sahelian drought. This could possibly be countered by injecting particles into the southern hemisphere stratosphere, which might have the effect of increasing rainfall in the Sahel countries. But any good there might be countered by a consequent failure of the rains in north-east Brazil. “Clearly, the juxtaposition of impacts leads us to believe that a global governance agreement for geo-engineering is essential before any practical geo-engineering system is deployed, and much further research is needed,” they conclude. – Climate News Network

EMBARGOED until 1700 GMT on Sunday 31 March Attempts to tackle climate change by altering the atmosphere – geo-engineering – may have unpredictable effects. They could even trigger disaster in a drought-prone region of Africa, a study suggests. LONDON, 31 March – Less than three weeks after two US researchers called for global agreement on the governance of geo-engineering research, British meteorologists have provided a case study in potential geo-engineering disaster. Jim Haywood from the Met Office Hadley Centre and colleagues report in Nature Climate Change that fine particles concentrated in the stratosphere could precipitate calamitous drought in the Sahel region of Africa. The team analysed historical observations from 1900 to 2010 and found that substantial volcanic eruptions in the Northern hemisphere – substantial enough to lift huge clouds of aerosols into the upper atmosphere – preceded three of the four driest summers in the region. Furious volcanic blasts have been historically associated with climate change: an eruption of Mt Tambora in what is now Indonesia in 1815 was followed by Europe’s notorious “year without a summer” in 1816, along with widespread harvest failure, famine and outbreaks of disease. The eruption of Mt Pinatubo in 1991 was followed by what climate scientists were later to call “the Pinatubo effect” – noticeable global cooling in the following years. But what concerns Professor Haywood and others is not the random nature of volcanic eruption – difficult to predict and impossible to prevent – but the possibility of deliberate injection of aerosols into the stratosphere to moderate global warming. The Sahel is the name given to a 1,000-kilometre band of savannah in Africa south of the Sahara, stretching from Mauretania in the west to Eritrea on the Red Sea coast. The four driest periods in this relatively arid region – these periods bear the deadpan scientific label of negative Sahelian precipitation anomalies – were in 1913, 1972, 1983 and 1984. Three of these dry spells followed an eruption of Katmai in Alaska in 1912 and of El Chichon in Mexico in 1982.

“…a global governance agreement for geo-engineering is essential before any practical geo-engineering system is deployed…”

The extended drought between 1970 and 1990 in the Sahel region claimed 250,000 lives and created 10 million refugees: it was one of the world’s biggest humanitarian disasters. All kinds of causes were evoked, including overgrazing, natural variability and industrial exhausts, but Professor Haywood and his colleagues think that volcanic eruptions also strongly influence the sea temperatures in the Atlantic, which are associated with Sahelian drought. Their conclusions are provisional. Such associations are difficult to prove conclusively. They concede in their paper that “correlation does not prove causality and the sparsity of significant hemispherically asymmetric volcanic eruptions in the recent historical record hampers definitive attribution.” In other words, the jury is still out. They simulated the impact of continued global warming into the future and found that – provided there was no geoengineering – only 11 of the 50 years between 2020 and 2070 would have negative Sahelian precipitation anomalies. Deliberate geoengineering, however, by loading aerosols into the northern hemisphere stratosphere would cause Sahelian drought. This could possibly be countered by injecting particles into the southern hemisphere stratosphere, which might have the effect of increasing rainfall in the Sahel countries. But any good there might be countered by a consequent failure of the rains in north-east Brazil. “Clearly, the juxtaposition of impacts leads us to believe that a global governance agreement for geo-engineering is essential before any practical geo-engineering system is deployed, and much further research is needed,” they conclude. – Climate News Network