Tag Archives: Lakes

Bolivian glaciers melt at alarming rate

glaciers
glaciers

A new study mapping the effects of dwindling glaciers on people living in Bolivia reveals rapid shrinkage and potentially dangerous glacial lakes.

LONDON, 22 October, 2016 Between 1986 and 2014 – one human generation – the glaciers of Bolivia shrank by 43%, according to new research.

This presents a problem in the long term for more than 2 million people who rely on glacial meltwater supply in the dry season, and immediate danger in the short term for thousands who might live below precarious glacial lakes.

Glaciers are in retreat as the world warms − a consequence of rising levels of carbon dioxide in the atmosphere in response to the increasing combustion of fossil fuels.

They are dwindling almost everywhere in the Andean chain, in Greenland, in Alaska and Canada, the Himalayas, across the entire mass of Central Asia, and everywhere in the tropics.

Tropical glaciers

But a new study in The Cryosphere, the journal of the European Geosciences Union, is one of the first to examine in detail precisely what this retreat could mean for the human communities in Bolivia, home to one-fifth of the world’s tropical glaciers.

Researchers from two British universities and a Bolivian colleague examined NASA satellite images of the region and found that the area of the Bolivia Cordillera Oriental normally covered by glaciers fell from 530 square kilometres in 1986 to about 300 sq km in 2014 − a shrinkage of more than two-fifths.

They then turned to the glacial lakes − bodies of water left behind as a glacier retreats. Some are in natural dips in the bedrock, some are accidentally dammed behind walls of glacial debris.

All such lakes are precarious: rockfalls, earthquakes and avalanches can breach them or tip water from them to create a dangerous downstream flow.

We mapped hundreds of lakes,” says Simon Cook, senior lecturer in physical geography at Manchester Metropolitan University, who led the study.

Some lakes are very small and pose little risk. Others are very large, but there’s little or no possibility that they would drain catastrophically. Others are large enough to create a big flood, and sit beneath steep slopes or steep glaciers, and could be dangerous.”

Studies such as these are a demonstration that climate change is happening, and that science can deliver practical help to communities in the path of potential disaster or economic stress.

Most glaciers will be gone or much diminished
by the end of the century – so where will the water come from in the dry season?”

Civil engineers, geographers, conservationists and hydraulic engineers are no longer simply warning about the hazards of climate change. They have begun to identify the communities most vulnerable to flooding, the hazards to local biodiversity as forests and grasslands begin to feel the heat, and the cities most at risk from routine coastal flooding as sea levels rise. and the US states that must start planning now for future power disruption as a consequence of drought.

Meltwater matters to mountain communities. It supplies the drive for hydroelectric power and it delivers clean drinking water to the cities and irrigation for crops in the dry season.

Reservoirs at risk

Through the year, the 2.3 million people in the Bolivian cities of La Paz and El Alto get 15% of their water from glacial supplies; in the dry season, this figure doubles. Glacial meltwater also keeps regional rivers and lakes topped up. So as the glaciers retreat and the body of surviving ice dwindles, some of these reservoirs, too, are at risk.

The researchers pinpointed 25 lakes as potentially dangerous. Even the smallest, were it to drain completely, would tip a peak flow of 600 cubic metres of water a second down the hillside. The largest could discharge 125,000 cubic metres − 50 times the volume of an Olympic swimming pool − every second.

A glacial lake outburst in 2009 killed farm animals, destroyed crops and washed away a road, leaving villagers isolated for months.

Dr Cook says: “We considered that a lake was dangerous if there were settlements or infrastructure down-valley from the lake, and if the slopes and glaciers around the lake were very steep, meaning that they could shed ice or snow or rock into the lake, which would cause it to overtop and generate a flood – a bit like jumping into a swimming pool, but on a much bigger scale.

Most glaciers will be gone or much diminished by the end of the century – so where will the water come from in the dry season?

Big cities like La Paz are partially dependent on meltwater from glaciers. But little is known about potential water resource stress in more remote areas. Much more work needs to be done on this issue.” Climate News Network

A new study mapping the effects of dwindling glaciers on people living in Bolivia reveals rapid shrinkage and potentially dangerous glacial lakes.

LONDON, 22 October, 2016 Between 1986 and 2014 – one human generation – the glaciers of Bolivia shrank by 43%, according to new research.

This presents a problem in the long term for more than 2 million people who rely on glacial meltwater supply in the dry season, and immediate danger in the short term for thousands who might live below precarious glacial lakes.

Glaciers are in retreat as the world warms − a consequence of rising levels of carbon dioxide in the atmosphere in response to the increasing combustion of fossil fuels.

They are dwindling almost everywhere in the Andean chain, in Greenland, in Alaska and Canada, the Himalayas, across the entire mass of Central Asia, and everywhere in the tropics.

Tropical glaciers

But a new study in The Cryosphere, the journal of the European Geosciences Union, is one of the first to examine in detail precisely what this retreat could mean for the human communities in Bolivia, home to one-fifth of the world’s tropical glaciers.

Researchers from two British universities and a Bolivian colleague examined NASA satellite images of the region and found that the area of the Bolivia Cordillera Oriental normally covered by glaciers fell from 530 square kilometres in 1986 to about 300 sq km in 2014 − a shrinkage of more than two-fifths.

They then turned to the glacial lakes − bodies of water left behind as a glacier retreats. Some are in natural dips in the bedrock, some are accidentally dammed behind walls of glacial debris.

All such lakes are precarious: rockfalls, earthquakes and avalanches can breach them or tip water from them to create a dangerous downstream flow.

We mapped hundreds of lakes,” says Simon Cook, senior lecturer in physical geography at Manchester Metropolitan University, who led the study.

Some lakes are very small and pose little risk. Others are very large, but there’s little or no possibility that they would drain catastrophically. Others are large enough to create a big flood, and sit beneath steep slopes or steep glaciers, and could be dangerous.”

Studies such as these are a demonstration that climate change is happening, and that science can deliver practical help to communities in the path of potential disaster or economic stress.

Most glaciers will be gone or much diminished
by the end of the century – so where will the water come from in the dry season?”

Civil engineers, geographers, conservationists and hydraulic engineers are no longer simply warning about the hazards of climate change. They have begun to identify the communities most vulnerable to flooding, the hazards to local biodiversity as forests and grasslands begin to feel the heat, and the cities most at risk from routine coastal flooding as sea levels rise. and the US states that must start planning now for future power disruption as a consequence of drought.

Meltwater matters to mountain communities. It supplies the drive for hydroelectric power and it delivers clean drinking water to the cities and irrigation for crops in the dry season.

Reservoirs at risk

Through the year, the 2.3 million people in the Bolivian cities of La Paz and El Alto get 15% of their water from glacial supplies; in the dry season, this figure doubles. Glacial meltwater also keeps regional rivers and lakes topped up. So as the glaciers retreat and the body of surviving ice dwindles, some of these reservoirs, too, are at risk.

The researchers pinpointed 25 lakes as potentially dangerous. Even the smallest, were it to drain completely, would tip a peak flow of 600 cubic metres of water a second down the hillside. The largest could discharge 125,000 cubic metres − 50 times the volume of an Olympic swimming pool − every second.

A glacial lake outburst in 2009 killed farm animals, destroyed crops and washed away a road, leaving villagers isolated for months.

Dr Cook says: “We considered that a lake was dangerous if there were settlements or infrastructure down-valley from the lake, and if the slopes and glaciers around the lake were very steep, meaning that they could shed ice or snow or rock into the lake, which would cause it to overtop and generate a flood – a bit like jumping into a swimming pool, but on a much bigger scale.

Most glaciers will be gone or much diminished by the end of the century – so where will the water come from in the dry season?

Big cities like La Paz are partially dependent on meltwater from glaciers. But little is known about potential water resource stress in more remote areas. Much more work needs to be done on this issue.” Climate News Network

Saving lives via mobile phone weather warnings

FOR IMMEDIATE RELEASE As extreme weather events become more common because of climate change, the mobile phone is increasingly being recognised as an important tool for warnings that can not only save lives – but also, in Brazil, the coffee crop. SAO PAULO, 19 June – Over the last few years, violent storms, leading to flooding and mudslides, have become more frequent in Brazil.   In 2011, violent rainstorms wreaked havoc in and around Rio. Houses built on steep hillsides were swept away by devastating mudslides. An entire shantytown built on top of a former rubbish dump in Niteroi collapsed, killing over 50 inhabitants. In Novo Friburgo, a mountainous town settled by 265 Swiss families in 1820, and the surrounding region, over 1000 people died in January 2011, after several days of violent rains. Sirens had sounded to warn people to evacuate, but many people either did not hear them, or ignored them. The permanent solution of course, would be to provide better housing in safer areas, but that is still many years away. Now a scheme successfully tried on the other side of the Atlantic is to be launched in the region. The scheme was piloted on Lake Victoria, a giant lake the size of Ireland, which is shared by three countries, Uganda, Kenya and Tanzania.   Five thousand die Its size makes it large enough to create its own weather, and conditions can change suddenly, with winds quickly whipping up six-foot waves capable of capsizing ferries and fishing boats.  Up to five thousand of the Lake’s estimated 200,000 fishermen were dying every year due to these freak storms. The African scheme is a joint initiative between the UK’s Met Office, the Ugandan Department of Meteorology, and the telecommunications company Ericsson. Text messages are sent to the mobile phones of local fishermen, warning them of changes in the weather. Before, there were no forecasting services relevant to fishermen in the region, making access to weather information almost impossible. To capture more accurate information about the local weather conditions, the Met Office set up a 4 km resolution weather forecast model over Lake Victoria. Tom Butcher, External Relations Manager at the Met Office explained:  “A lot of the weather patterns on the lake happen on quite a small scale and are driven by the difference in temperature between the lake’s water and the surrounding land. You get warm moist air at night, rising above the lake and sucking in colder air from over the land surface – a convective process that creates a lot of storms.”   Red means danger To get round the problem of illiteracy among the fishermen, the forecasters at Uganda`s Department of Meteorology adopted the Met Office’s traffic light system of colour-coded weather warnings. Green means winds of less than five knots and no significant weather conditions predicted, therefore a very low hazard threshold, no advice needed. Red means a high likelihood of 20 knots+ winds, or severe thunderstorms, therefore a high hazard threshold and advice to ‘take action’. The project was enthusiastically received by the fishermen and within a few weeks it was saving lives. In Rio, the scheme involves attaching rain gauges (pluviometers) to mobile phone masts to give warnings in real time of extreme weather and high rainfalls to mobile phone users with 3G, via their providers. The scheme will eventually be extended to 19 Brazilian states, with the attachment of rain gauges to 1500 masts.  Experience has shown that sirens are often ignored, or not heard, but a direct message aimed at a phone user personally is much more effective.   Four hours warning This is the first scheme to use a direct link between rain gauges and the mobile phone users.  A small-scale scheme, based on information collected via satellite and from a network of meteorological radars maintained by the administration, is already in use, under a partnership between the Rio city authorities, the Civil Defence department and four major mobile phone operators. The warnings of high rainfall are transmitted by SMS about four hours before they are due. The Civil Defence also has a special warning programme for 3,500 health agents who work in 117 risk areas. The agents, each responsible for about 100 families, are then expected to spread the warnings by word of mouth. When the rainfall tops 40mm in an hour, or 125 mm in 24 hours, then the agents receive messages telling them to evacuate people. Mobile phone weather warnings are not only being used for rainfall. It may surprise some readers, who think of Brazil only as a tropical country, to know that in the southern state of Paraná, frost alerts for the region’s coffee farmers are also being sent by SMS to mobile phones. The initiative, which began in 2012, is the result of a partnership between IAPAR, Parana’s Agricultural Institute and the state’s meteorological system, SIMEPAR. Paulo Henrique Caramori, coordinator of Iapar’s Agrometeorology department, said: “the SMS service is direct and very quick and enables the coffee growers to speed up protection measures for their trees”. – Climate News Network  

FOR IMMEDIATE RELEASE As extreme weather events become more common because of climate change, the mobile phone is increasingly being recognised as an important tool for warnings that can not only save lives – but also, in Brazil, the coffee crop. SAO PAULO, 19 June – Over the last few years, violent storms, leading to flooding and mudslides, have become more frequent in Brazil.   In 2011, violent rainstorms wreaked havoc in and around Rio. Houses built on steep hillsides were swept away by devastating mudslides. An entire shantytown built on top of a former rubbish dump in Niteroi collapsed, killing over 50 inhabitants. In Novo Friburgo, a mountainous town settled by 265 Swiss families in 1820, and the surrounding region, over 1000 people died in January 2011, after several days of violent rains. Sirens had sounded to warn people to evacuate, but many people either did not hear them, or ignored them. The permanent solution of course, would be to provide better housing in safer areas, but that is still many years away. Now a scheme successfully tried on the other side of the Atlantic is to be launched in the region. The scheme was piloted on Lake Victoria, a giant lake the size of Ireland, which is shared by three countries, Uganda, Kenya and Tanzania.   Five thousand die Its size makes it large enough to create its own weather, and conditions can change suddenly, with winds quickly whipping up six-foot waves capable of capsizing ferries and fishing boats.  Up to five thousand of the Lake’s estimated 200,000 fishermen were dying every year due to these freak storms. The African scheme is a joint initiative between the UK’s Met Office, the Ugandan Department of Meteorology, and the telecommunications company Ericsson. Text messages are sent to the mobile phones of local fishermen, warning them of changes in the weather. Before, there were no forecasting services relevant to fishermen in the region, making access to weather information almost impossible. To capture more accurate information about the local weather conditions, the Met Office set up a 4 km resolution weather forecast model over Lake Victoria. Tom Butcher, External Relations Manager at the Met Office explained:  “A lot of the weather patterns on the lake happen on quite a small scale and are driven by the difference in temperature between the lake’s water and the surrounding land. You get warm moist air at night, rising above the lake and sucking in colder air from over the land surface – a convective process that creates a lot of storms.”   Red means danger To get round the problem of illiteracy among the fishermen, the forecasters at Uganda`s Department of Meteorology adopted the Met Office’s traffic light system of colour-coded weather warnings. Green means winds of less than five knots and no significant weather conditions predicted, therefore a very low hazard threshold, no advice needed. Red means a high likelihood of 20 knots+ winds, or severe thunderstorms, therefore a high hazard threshold and advice to ‘take action’. The project was enthusiastically received by the fishermen and within a few weeks it was saving lives. In Rio, the scheme involves attaching rain gauges (pluviometers) to mobile phone masts to give warnings in real time of extreme weather and high rainfalls to mobile phone users with 3G, via their providers. The scheme will eventually be extended to 19 Brazilian states, with the attachment of rain gauges to 1500 masts.  Experience has shown that sirens are often ignored, or not heard, but a direct message aimed at a phone user personally is much more effective.   Four hours warning This is the first scheme to use a direct link between rain gauges and the mobile phone users.  A small-scale scheme, based on information collected via satellite and from a network of meteorological radars maintained by the administration, is already in use, under a partnership between the Rio city authorities, the Civil Defence department and four major mobile phone operators. The warnings of high rainfall are transmitted by SMS about four hours before they are due. The Civil Defence also has a special warning programme for 3,500 health agents who work in 117 risk areas. The agents, each responsible for about 100 families, are then expected to spread the warnings by word of mouth. When the rainfall tops 40mm in an hour, or 125 mm in 24 hours, then the agents receive messages telling them to evacuate people. Mobile phone weather warnings are not only being used for rainfall. It may surprise some readers, who think of Brazil only as a tropical country, to know that in the southern state of Paraná, frost alerts for the region’s coffee farmers are also being sent by SMS to mobile phones. The initiative, which began in 2012, is the result of a partnership between IAPAR, Parana’s Agricultural Institute and the state’s meteorological system, SIMEPAR. Paulo Henrique Caramori, coordinator of Iapar’s Agrometeorology department, said: “the SMS service is direct and very quick and enables the coffee growers to speed up protection measures for their trees”. – 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

Warming bad for life in freshwater lakes and rivers

For immediate release On both sides of the Atlantic scientists studying lakes have discovered they are warming – and this is bad news both for water quality and the fish. London, 14 June – The Alpine lakes of Austria are warming up. By 2050, their surface waters could be up to 3°C warmer, according to new research in the journal Hydrobiologia. Martin Dokulil of the Institute for Limnology at the University of Innsbruck studied data from nine lakes larger than 10km2. The largest, Bodensee or Lake Constance, touches Austria’s border with Germany and Switzerland to the west; 800 kms to the east, Neusiedler See borders Germany and Hungary. The nine lakes range from 254 to 1.8 metres maximum depth and they are vital to Austria’s tourist industry: they play powerful roles in the Alpine ecosystem and they are of course reservoirs of water. But the Alpine valleys are warming: between 1980 and 1999 the region warmed at three times the global average and by 2050 the median temperatures for the region could have risen by 3.5°C. The challenge has been to anticipate the impact of global warming on the lakes. “The predicted changes in surface water temperatures will affect the thermal characteristics of the lakes,” says Dr Dokulil. “Warmer water temperatures could lead to enhanced nutrient loads and affect water quality by promoting algal blooms and impairing the biological functions of aquatic organisms. “Significant increases in summer temperatures will affect the carbon cycling in the lakes, with potential consequences on atmospheric carbon dioxide levels and the Earth’s climate.”  Next, the fish The Austrian research so far is concerned only with freshwater temperatures. Peter Moyle, a biologist at the University of California Davis, has been more concerned with the freshwater fish that make their homes in, or migrate to, California’s rivers and lakes. He and colleagues report in the journal PLOS One – the Public Library of Science – that if current climate trends continue, then 82 per cent of California’s native fish could be extinct, and their native homes colonized by invasive species. The scientists looked at 121 native species and found that four fifths of them were likely to be driven to extinction or at least to very low numbers. These include prized sporting fish such as the Klamath River summer steelhead and other trout, the Central Valley Chinook salmon, the Central Coast coho salmon and many others that depend on cold water. “These fish are part of the endemic flora and fauna that makes California such a special place,” said Prof Moyle. “As we lose these fishes, we lose their environments and are much poorer for it.” – Climate News Network        

For immediate release On both sides of the Atlantic scientists studying lakes have discovered they are warming – and this is bad news both for water quality and the fish. London, 14 June – The Alpine lakes of Austria are warming up. By 2050, their surface waters could be up to 3°C warmer, according to new research in the journal Hydrobiologia. Martin Dokulil of the Institute for Limnology at the University of Innsbruck studied data from nine lakes larger than 10km2. The largest, Bodensee or Lake Constance, touches Austria’s border with Germany and Switzerland to the west; 800 kms to the east, Neusiedler See borders Germany and Hungary. The nine lakes range from 254 to 1.8 metres maximum depth and they are vital to Austria’s tourist industry: they play powerful roles in the Alpine ecosystem and they are of course reservoirs of water. But the Alpine valleys are warming: between 1980 and 1999 the region warmed at three times the global average and by 2050 the median temperatures for the region could have risen by 3.5°C. The challenge has been to anticipate the impact of global warming on the lakes. “The predicted changes in surface water temperatures will affect the thermal characteristics of the lakes,” says Dr Dokulil. “Warmer water temperatures could lead to enhanced nutrient loads and affect water quality by promoting algal blooms and impairing the biological functions of aquatic organisms. “Significant increases in summer temperatures will affect the carbon cycling in the lakes, with potential consequences on atmospheric carbon dioxide levels and the Earth’s climate.”  Next, the fish The Austrian research so far is concerned only with freshwater temperatures. Peter Moyle, a biologist at the University of California Davis, has been more concerned with the freshwater fish that make their homes in, or migrate to, California’s rivers and lakes. He and colleagues report in the journal PLOS One – the Public Library of Science – that if current climate trends continue, then 82 per cent of California’s native fish could be extinct, and their native homes colonized by invasive species. The scientists looked at 121 native species and found that four fifths of them were likely to be driven to extinction or at least to very low numbers. These include prized sporting fish such as the Klamath River summer steelhead and other trout, the Central Valley Chinook salmon, the Central Coast coho salmon and many others that depend on cold water. “These fish are part of the endemic flora and fauna that makes California such a special place,” said Prof Moyle. “As we lose these fishes, we lose their environments and are much poorer for it.” – Climate News Network