Tag Archives: Rainfall

Ancient water-saving can help modern Peru

Ancient water-saving methods may help Lima, Peru’s capital, through its water crisis, caused by climate change and population growth.

LONDON, 2 July, 2019 − There’s plenty to learn in modern Peru from the designers of ancient water-saving methods, scientists are finding. Our forebears could even keep the capital’s taps running through the summer heat.

Lima, Peru’s desert capital, a city of 12 million people, expects to run out of water by 2025. It already faces a crisis each summer as the supply from the mountains dwindles to a trickle. Yet the quantity of rain in the wet season can be overwhelming.

Between the Andes and the Pacific ocean, Lima sits on a coastal plain where the average rainfall is a tiny 9 mm a year, and it has to rely on the snow melt from the mountains and glaciers to provide summer drinking water and the needs of industry and farming.

But with the glaciers disappearing because of climate change, and the population increasing, the city will soon become untenable for many of the poor in summer, unless water supplies can be improved.

A group of scientists has found that reviving systems developed 1,400 years ago by local people before the Inca empire existed could harvest water from the winter rainy season in the mountains to ensure Lima’s summer supplies.

“You’d be forgiven for wondering how ancient methods could apply to modern-day problems. However we have lots to learn from our ancestors’ creative problem-solving skills”

Researchers from Imperial College London and their colleagues at the Regional Initiative for Hydrological Monitoring of Andean Ecosystems studied a water system in Huamantanga, in the central Andes, one of the last of its kind.

The local people still use a method developed in 600 AD by Peruvian civilisations that created systems in the mountains to divert excess rainwater from source streams through ponds and canals onto mountain slopes and down through fissures in the rocks.

The water would take weeks or even months to trickle through the system and resurface downstream – just in time for the dry season.

The researchers used dye tracers and hydrological monitoring to study the system from the wet to dry seasons of 2014–2015 and 2015–2016. Social scientists involved also worked with Huamantanga’s local people to understand the practice and help map the landscape.

Big increase

They found the water took between two weeks and eight months to re-emerge, with an average time of 45 days. From these timescales, they calculated that, if governments upscale the systems to cater for today’s population size, they could reroute and delay 35% of wet season water, equivalent to 99 million cubic metres per year of water flowing through Lima’s natural terrain.

This could increase the water available in the dry season by up to 33% in the early months, and an average of 7.5% for the rest of the summer.

The method could essentially extend the wet season, providing more drinking water and longer crop-growing periods for local farmers.

The study, published in the journal Nature Sustainability, is the first to examine the pre-Inca system in this much detail to find answers to modern problems. The authors say their research shows how indigenous systems could complement modern engineering solutions for water security in coastal Peru.

Lead author Dr Boris Ochoa-Tocachi, from Imperial’s Department of Civil and Environmental Engineering, said: “With the advent of modern science, you’d be forgiven for wondering how ancient methods could apply to modern-day problems. However, it turns out that we have lots to learn from our ancestors’ creative problem-solving skills.”

Growing too fast

Senior author Dr Wouter Buytaert, from the same department, said: “Like many tropical cities, Lima’s population is growing fast – too fast for water reserves to keep up during dry seasons. Upscaling existing pre-Inca systems could help relieve Peru’s wet months of water and quench its dry ones.”

The seasonal variability typical of coastal Peru is worsened by human impacts. Apart from glacier melting caused by global warming, humans also contribute to erosion, which renders soil too weak to support dams big enough to hold all the water needed in the summer.

Climate change also makes wet seasons wetter, and dry seasons drier − making the need for effective water storage in Peru even more urgent.

The authors say combining pre-Inca systems with classic structures, such as smaller dams, could also help to improve adaptability and water supply in an unpredictable climate. − Climate News Network

Ancient water-saving methods may help Lima, Peru’s capital, through its water crisis, caused by climate change and population growth.

LONDON, 2 July, 2019 − There’s plenty to learn in modern Peru from the designers of ancient water-saving methods, scientists are finding. Our forebears could even keep the capital’s taps running through the summer heat.

Lima, Peru’s desert capital, a city of 12 million people, expects to run out of water by 2025. It already faces a crisis each summer as the supply from the mountains dwindles to a trickle. Yet the quantity of rain in the wet season can be overwhelming.

Between the Andes and the Pacific ocean, Lima sits on a coastal plain where the average rainfall is a tiny 9 mm a year, and it has to rely on the snow melt from the mountains and glaciers to provide summer drinking water and the needs of industry and farming.

But with the glaciers disappearing because of climate change, and the population increasing, the city will soon become untenable for many of the poor in summer, unless water supplies can be improved.

A group of scientists has found that reviving systems developed 1,400 years ago by local people before the Inca empire existed could harvest water from the winter rainy season in the mountains to ensure Lima’s summer supplies.

“You’d be forgiven for wondering how ancient methods could apply to modern-day problems. However we have lots to learn from our ancestors’ creative problem-solving skills”

Researchers from Imperial College London and their colleagues at the Regional Initiative for Hydrological Monitoring of Andean Ecosystems studied a water system in Huamantanga, in the central Andes, one of the last of its kind.

The local people still use a method developed in 600 AD by Peruvian civilisations that created systems in the mountains to divert excess rainwater from source streams through ponds and canals onto mountain slopes and down through fissures in the rocks.

The water would take weeks or even months to trickle through the system and resurface downstream – just in time for the dry season.

The researchers used dye tracers and hydrological monitoring to study the system from the wet to dry seasons of 2014–2015 and 2015–2016. Social scientists involved also worked with Huamantanga’s local people to understand the practice and help map the landscape.

Big increase

They found the water took between two weeks and eight months to re-emerge, with an average time of 45 days. From these timescales, they calculated that, if governments upscale the systems to cater for today’s population size, they could reroute and delay 35% of wet season water, equivalent to 99 million cubic metres per year of water flowing through Lima’s natural terrain.

This could increase the water available in the dry season by up to 33% in the early months, and an average of 7.5% for the rest of the summer.

The method could essentially extend the wet season, providing more drinking water and longer crop-growing periods for local farmers.

The study, published in the journal Nature Sustainability, is the first to examine the pre-Inca system in this much detail to find answers to modern problems. The authors say their research shows how indigenous systems could complement modern engineering solutions for water security in coastal Peru.

Lead author Dr Boris Ochoa-Tocachi, from Imperial’s Department of Civil and Environmental Engineering, said: “With the advent of modern science, you’d be forgiven for wondering how ancient methods could apply to modern-day problems. However, it turns out that we have lots to learn from our ancestors’ creative problem-solving skills.”

Growing too fast

Senior author Dr Wouter Buytaert, from the same department, said: “Like many tropical cities, Lima’s population is growing fast – too fast for water reserves to keep up during dry seasons. Upscaling existing pre-Inca systems could help relieve Peru’s wet months of water and quench its dry ones.”

The seasonal variability typical of coastal Peru is worsened by human impacts. Apart from glacier melting caused by global warming, humans also contribute to erosion, which renders soil too weak to support dams big enough to hold all the water needed in the summer.

Climate change also makes wet seasons wetter, and dry seasons drier − making the need for effective water storage in Peru even more urgent.

The authors say combining pre-Inca systems with classic structures, such as smaller dams, could also help to improve adaptability and water supply in an unpredictable climate. − Climate News Network

Climate change blamed as Chennai runs dry

The monsoon’s failure and government mismanagement in the Indian state of Tamil Nadu are being blamed as Chennai runs dry.

CHENNAI, 1 July, 2019 − Some of the poorest people of India’s sixth largest city are having to spend half their weekly income on water as Chennai runs dry: its four reservoirs lie empty and the government’s relief tankers cannot keep up with demand from citizens.

Despite government claims that there is no water crisis, the taps are empty and many of Chennai’s nine million people are queuing from early morning, awaiting what water the tankers can deliver.

Monsoon rains have failed for the last two years, leaving the city enduring a heat wave with no water. The government is delivering 10 million litres daily by train from 200 kilometres away in a bid to provide enough water for the poor to survive. In the richer areas private water tankers are maintaining supplies, charging double the normal rate to fill a roof tank.

Businesses, particularly restaurants, have been forced to close, and children are not attending school because they are spending all day queuing for water for their families.

Although it is clear that climate change is affecting the monsoon’s pattern and it may be October before Chennai gets enough water to restore supplies to normal, government mismanagement is also being blamed.

Contrasting views

The city’s plight has been highlighted by Leonardo DiCaprio, the American actor and environmentalist, who is a UN climate change ambassador.

His message is in stark contrast to that from Tamil Nadu chief minister Edappadi K Palaniswami. He told the media he uses only two pots of water every day, and that his government is taking good care of its citizens. This was after local media reported that his house in Chennai was receiving two truckloads of water a day.

A senior official in the Chennai metro water board said that efforts had been made since early June to ensure residents’ minimum water needs were met: “The government has initiated plans to bring water from nearby districts. Since the monsoon rains failed consecutively for the third year, we couldn’t store any water.”

He said sources in use now included water from stone quarries, two desalination plants in the city, a local lake and some borewells in the suburbs.

The government is trying to suppress demonstrations. When a voluntary organisation, Arappor Iyakkam, sought permission from the Chennai police commissioner for a protest about the water crisis, he refused, citing what he said was the need to protect law and order and the effect on peace and tranquillity at a time when the government was already striving to provide water. So the protestors approached the Madras high court for permission to go ahead.

“The government does not stop supplying water for multi-national companies when its own people are struggling to quench their thirst’’

According to Arappor Iyakkam’s co-ordinator, Jayaraman, the court said public awareness about the crisis was important, and granted permission. Iyakkam said: “Chennai and many parts of Tamil Nadu are facing an acute water crisis, and this has arisen due to continuous neglect of water bodies, and maladministration and corruption by the ruling governments.

“The present government has been in a denial mode, acknowledging the level of water shortage and its failure to work on solutions. Our campaign would emphasise the need for action on a war footing.”

Social activist Arul Doss argues that the government is losing its focus on seeking long-term solutions and is instead spending money on desalination plants. “The rich can afford to buy water for double the price. But the poor workers are now forced to spend half of their salary for water. What kind of development are we heading to?

“The government does not stop supplying water for multi-national companies when its own people are struggling to quench their thirst,’’ he said.

“Instead of spending money on recycling water and de-silting all the water bodies before the monsoon season, the government is working hard on opening new desalination plants in Chennai. It is hard to believe this is the same city that suffered flash floods in 2015.

Getting worse

“At least by now the government should have cleaned up water bodies and ensured grey water usage in high-rise apartments in the city,’’ Arul Doss told Climate News Network.

The plight of ordinary people is growing more extreme. A Chennai resident, K Meena, a student, has to fetch water. “We have to depend on the tanker supply, because the taps in our streets have dried up. Ours is a family of five. My parents and siblings take turns to collect water for bathing and cooking. I skipped classes and went late to college because I had to wait for the lorry,” said Meena.

Cab driver A Logeswaran uses the toilet facilities at petrol stations and sleeps in his car every other night to avoid using precious water supplies at home, which are kept for his wife and three-year-old child.

“Some of my neighbours sent their children and wives back to their native villages due to the water crisis. This is a very sad state for our city. Water is a basic need and I feel the government has failed completely,’’ he said in despair. − Climate News Network

The monsoon’s failure and government mismanagement in the Indian state of Tamil Nadu are being blamed as Chennai runs dry.

CHENNAI, 1 July, 2019 − Some of the poorest people of India’s sixth largest city are having to spend half their weekly income on water as Chennai runs dry: its four reservoirs lie empty and the government’s relief tankers cannot keep up with demand from citizens.

Despite government claims that there is no water crisis, the taps are empty and many of Chennai’s nine million people are queuing from early morning, awaiting what water the tankers can deliver.

Monsoon rains have failed for the last two years, leaving the city enduring a heat wave with no water. The government is delivering 10 million litres daily by train from 200 kilometres away in a bid to provide enough water for the poor to survive. In the richer areas private water tankers are maintaining supplies, charging double the normal rate to fill a roof tank.

Businesses, particularly restaurants, have been forced to close, and children are not attending school because they are spending all day queuing for water for their families.

Although it is clear that climate change is affecting the monsoon’s pattern and it may be October before Chennai gets enough water to restore supplies to normal, government mismanagement is also being blamed.

Contrasting views

The city’s plight has been highlighted by Leonardo DiCaprio, the American actor and environmentalist, who is a UN climate change ambassador.

His message is in stark contrast to that from Tamil Nadu chief minister Edappadi K Palaniswami. He told the media he uses only two pots of water every day, and that his government is taking good care of its citizens. This was after local media reported that his house in Chennai was receiving two truckloads of water a day.

A senior official in the Chennai metro water board said that efforts had been made since early June to ensure residents’ minimum water needs were met: “The government has initiated plans to bring water from nearby districts. Since the monsoon rains failed consecutively for the third year, we couldn’t store any water.”

He said sources in use now included water from stone quarries, two desalination plants in the city, a local lake and some borewells in the suburbs.

The government is trying to suppress demonstrations. When a voluntary organisation, Arappor Iyakkam, sought permission from the Chennai police commissioner for a protest about the water crisis, he refused, citing what he said was the need to protect law and order and the effect on peace and tranquillity at a time when the government was already striving to provide water. So the protestors approached the Madras high court for permission to go ahead.

“The government does not stop supplying water for multi-national companies when its own people are struggling to quench their thirst’’

According to Arappor Iyakkam’s co-ordinator, Jayaraman, the court said public awareness about the crisis was important, and granted permission. Iyakkam said: “Chennai and many parts of Tamil Nadu are facing an acute water crisis, and this has arisen due to continuous neglect of water bodies, and maladministration and corruption by the ruling governments.

“The present government has been in a denial mode, acknowledging the level of water shortage and its failure to work on solutions. Our campaign would emphasise the need for action on a war footing.”

Social activist Arul Doss argues that the government is losing its focus on seeking long-term solutions and is instead spending money on desalination plants. “The rich can afford to buy water for double the price. But the poor workers are now forced to spend half of their salary for water. What kind of development are we heading to?

“The government does not stop supplying water for multi-national companies when its own people are struggling to quench their thirst,’’ he said.

“Instead of spending money on recycling water and de-silting all the water bodies before the monsoon season, the government is working hard on opening new desalination plants in Chennai. It is hard to believe this is the same city that suffered flash floods in 2015.

Getting worse

“At least by now the government should have cleaned up water bodies and ensured grey water usage in high-rise apartments in the city,’’ Arul Doss told Climate News Network.

The plight of ordinary people is growing more extreme. A Chennai resident, K Meena, a student, has to fetch water. “We have to depend on the tanker supply, because the taps in our streets have dried up. Ours is a family of five. My parents and siblings take turns to collect water for bathing and cooking. I skipped classes and went late to college because I had to wait for the lorry,” said Meena.

Cab driver A Logeswaran uses the toilet facilities at petrol stations and sleeps in his car every other night to avoid using precious water supplies at home, which are kept for his wife and three-year-old child.

“Some of my neighbours sent their children and wives back to their native villages due to the water crisis. This is a very sad state for our city. Water is a basic need and I feel the government has failed completely,’’ he said in despair. − Climate News Network

Very heavy rain bouts are on the way

Here is the long-term forecast. Rain will become more torrential, flash floods more frequent. Very heavy rain is a simple response to global temperatures.

LONDON, 19 June, 2019 – Canadian scientists have examined an exhaustive collection of rain records for the past 50 years to confirm the fears of climate scientists: bouts of very heavy rain are on the increase.

They have measured this increase in parts of Canada, most of Europe, the US Midwest and Northeast, northern Australia, Western Russia and parts of China.

Between 2004 and 2013, worldwide, bouts of extreme rainfall rain increased by 7%. In Europe and Asia, the same decade registered a rise of 8.6% in cascades of heavy rain.

The scientists report in the journal Water Resources Research that they excluded areas where the records were less than complete, but analysed 8,700 daily rain records from 100,000 stations that monitor rainfall worldwide. They found that from 1964 to 2013, the frequency of catastrophic downpours increased with each decade.

“Our study of records from around the globe shows that potentially devastating bouts of extreme rain are increasing decade by decade”

“By introducing a new approach to analysing extremes, using thousands of rain records, we reveal a clear increase in the frequency of extreme rain events over the recent fifty years when global warming accelerated,” said Simon Papalexiou, of the University of Saskatchewan’s college of engineering.

“This upward trend is highly unlikely to be explained by natural climate variability. The probability of this happening is less than 0.3% under the model assumptions used.”

As temperatures rise, evaporation increases. A warmer atmosphere can absorb more moisture: capacity increases by 7% with each extra degree Celsius on the thermometer. Moisture absorbed into the atmosphere will inevitably fall again.

Flash flood threat

The world has warmed by at least 1°C in the last century, thanks to ever-increasing use of fossil fuels, and hydrologists, engineers and planners have been warning  for years that human settlements and low-lying terrains have a rainfall problem, in the form of flash floods that can overwhelm sewage treatment plants and increase water contamination: rain-induced floods have claimed half a million lives since 1980.

Such floods – and other studies have confirmed their increase – trigger landslides, wash away crops, overwhelm buildings and bridges, flood homes and block road transport.

And they could be expected to increase even more because of the phenomenal growth of the world’s cities, covering more ground with brick, tile, cement and tarmacadam, to reduce the available marsh, forest and grassland that usually absorbs much of any downpour.

Scientists have measured alarming increases in rainfall in urban Australia, linked the catastrophic floods delivered by Hurricane Harvey in 2017 over Houston in Texas to global warming, and warned more and worse is on the way.

Start planning now

“If global warming progresses as climate model projections predict, we had better plan for dealing with frequent heavy rain right now.

“Our study of records from around the globe shows that potentially devastating bouts of extreme rain are increasing decade by decade,” Dr Papalexiou said.

“We know that rainfall-induced floods can devastate communities, and that there are implications of increasing bouts of heavy rain for public health, agriculture, farmers’ livelihoods, the fishing industry and insurance, to name but a few.” – Climate News Network

Here is the long-term forecast. Rain will become more torrential, flash floods more frequent. Very heavy rain is a simple response to global temperatures.

LONDON, 19 June, 2019 – Canadian scientists have examined an exhaustive collection of rain records for the past 50 years to confirm the fears of climate scientists: bouts of very heavy rain are on the increase.

They have measured this increase in parts of Canada, most of Europe, the US Midwest and Northeast, northern Australia, Western Russia and parts of China.

Between 2004 and 2013, worldwide, bouts of extreme rainfall rain increased by 7%. In Europe and Asia, the same decade registered a rise of 8.6% in cascades of heavy rain.

The scientists report in the journal Water Resources Research that they excluded areas where the records were less than complete, but analysed 8,700 daily rain records from 100,000 stations that monitor rainfall worldwide. They found that from 1964 to 2013, the frequency of catastrophic downpours increased with each decade.

“Our study of records from around the globe shows that potentially devastating bouts of extreme rain are increasing decade by decade”

“By introducing a new approach to analysing extremes, using thousands of rain records, we reveal a clear increase in the frequency of extreme rain events over the recent fifty years when global warming accelerated,” said Simon Papalexiou, of the University of Saskatchewan’s college of engineering.

“This upward trend is highly unlikely to be explained by natural climate variability. The probability of this happening is less than 0.3% under the model assumptions used.”

As temperatures rise, evaporation increases. A warmer atmosphere can absorb more moisture: capacity increases by 7% with each extra degree Celsius on the thermometer. Moisture absorbed into the atmosphere will inevitably fall again.

Flash flood threat

The world has warmed by at least 1°C in the last century, thanks to ever-increasing use of fossil fuels, and hydrologists, engineers and planners have been warning  for years that human settlements and low-lying terrains have a rainfall problem, in the form of flash floods that can overwhelm sewage treatment plants and increase water contamination: rain-induced floods have claimed half a million lives since 1980.

Such floods – and other studies have confirmed their increase – trigger landslides, wash away crops, overwhelm buildings and bridges, flood homes and block road transport.

And they could be expected to increase even more because of the phenomenal growth of the world’s cities, covering more ground with brick, tile, cement and tarmacadam, to reduce the available marsh, forest and grassland that usually absorbs much of any downpour.

Scientists have measured alarming increases in rainfall in urban Australia, linked the catastrophic floods delivered by Hurricane Harvey in 2017 over Houston in Texas to global warming, and warned more and worse is on the way.

Start planning now

“If global warming progresses as climate model projections predict, we had better plan for dealing with frequent heavy rain right now.

“Our study of records from around the globe shows that potentially devastating bouts of extreme rain are increasing decade by decade,” Dr Papalexiou said.

“We know that rainfall-induced floods can devastate communities, and that there are implications of increasing bouts of heavy rain for public health, agriculture, farmers’ livelihoods, the fishing industry and insurance, to name but a few.” – Climate News Network

Siberia expects mass migration as it warms

Scientists mapping the effects of increased temperature and rainfall across Siberia say it could expect mass migration in a warmer world.

LONDON, 7 June, 2019 − Siberia, currently one of the most sparsely populated places in the northern hemisphere, could become a target for mass migration as the climate warms.

By 2080, scientists report, melting permafrost and warming summer and winter temperatures will mean that agriculture could thrive and support between five and seven times the current population.

Lands to the south are becoming far less able to feed and sustain their existing populations, as heat makes crops harder to grow and cities untenable, and mass migration northward is likely, the scientists predict.

Their study, which is produced by the Krasnoyarsk Federal Research Centre in Siberia and the US National Institute of Aerospace, says the current problem of falling population in Russia will be reversed as conditions in Siberia become much better for growing food, and both summers and winters more pleasant to live in. It is published in the journal Environmental Research Letters.

With 13 million square kilometres of land area, Asian Russia – east of the Urals, towards the Pacific – accounts for 77% of Russian territory. Its population, however, accounts for just 27% of the country’s people and is concentrated along the forest-steppe in the south, with its comfortable climate and fertile soil.

“In a future, warmer climate, food security, in terms of crop distribution and production capability, is predicted to become more favourable”

The findings have a certain irony, because at the close of the Communist era the Soviet government was not keen to take any action on climate change: it saw the warming of Siberia as a chance for the USSR to grow more wheat and challenge US dominance of the world’s grain supply.

The scientists warn, however, that mass migration will not be that simple. The melting of the permafrost threatens what little infrastructure there is in the region. Before a larger population could provide for itself, investments need to be made in new roads, railways and power supplies to support it.

They say warming in the region already exceeds earlier estimates. Depending on how much carbon dioxide humans continue to pump into the atmosphere, the scientists predict mid-winter temperatures over Asian Russia will increase between 3.4°C and 9.1°C by 2080. Increases in mid-summer will be between 1.9°C and 5.7°C, they say.

Permafrost, which currently covers 65% of the region, would fall to 40% by 2080, and crucially there will be increases in rainfall of between 60 mm and 140 mm, making the unfrozen area much more favourable for crops.

Migration ‘probable’

Using something called Ecological Landscape Potential, or ELP, to gauge the potential for land to support human populations, the scientists came to the conclusion that mass migration north was probable.

“We found the ELP would increase over most of Asian Russia, which would lead to a five- to seven-fold increase in the capacity of the territory to sustain and become attractive to human populations, which would then lead to migrations from less sustainable lands to Asian Russia during this century,” they say.

Dr Elena Parfenova, from the Krasnoyarsk centre, said: “In a future, warmer climate, food security, in terms of crop distribution and production capability, is predicted to become more favourable to support settlements in what is currently an extremely cold Asian Russia.”

She said that obviously people would flock first to the already developed areas in the south, but most of the area of Siberia and the Far East “have poorly developed infrastructure. The rapidity that these developments occur is dependent on investments in infrastructure and agriculture, which is dependent on the decisions that will be made in the near future.” − Climate News Network

Scientists mapping the effects of increased temperature and rainfall across Siberia say it could expect mass migration in a warmer world.

LONDON, 7 June, 2019 − Siberia, currently one of the most sparsely populated places in the northern hemisphere, could become a target for mass migration as the climate warms.

By 2080, scientists report, melting permafrost and warming summer and winter temperatures will mean that agriculture could thrive and support between five and seven times the current population.

Lands to the south are becoming far less able to feed and sustain their existing populations, as heat makes crops harder to grow and cities untenable, and mass migration northward is likely, the scientists predict.

Their study, which is produced by the Krasnoyarsk Federal Research Centre in Siberia and the US National Institute of Aerospace, says the current problem of falling population in Russia will be reversed as conditions in Siberia become much better for growing food, and both summers and winters more pleasant to live in. It is published in the journal Environmental Research Letters.

With 13 million square kilometres of land area, Asian Russia – east of the Urals, towards the Pacific – accounts for 77% of Russian territory. Its population, however, accounts for just 27% of the country’s people and is concentrated along the forest-steppe in the south, with its comfortable climate and fertile soil.

“In a future, warmer climate, food security, in terms of crop distribution and production capability, is predicted to become more favourable”

The findings have a certain irony, because at the close of the Communist era the Soviet government was not keen to take any action on climate change: it saw the warming of Siberia as a chance for the USSR to grow more wheat and challenge US dominance of the world’s grain supply.

The scientists warn, however, that mass migration will not be that simple. The melting of the permafrost threatens what little infrastructure there is in the region. Before a larger population could provide for itself, investments need to be made in new roads, railways and power supplies to support it.

They say warming in the region already exceeds earlier estimates. Depending on how much carbon dioxide humans continue to pump into the atmosphere, the scientists predict mid-winter temperatures over Asian Russia will increase between 3.4°C and 9.1°C by 2080. Increases in mid-summer will be between 1.9°C and 5.7°C, they say.

Permafrost, which currently covers 65% of the region, would fall to 40% by 2080, and crucially there will be increases in rainfall of between 60 mm and 140 mm, making the unfrozen area much more favourable for crops.

Migration ‘probable’

Using something called Ecological Landscape Potential, or ELP, to gauge the potential for land to support human populations, the scientists came to the conclusion that mass migration north was probable.

“We found the ELP would increase over most of Asian Russia, which would lead to a five- to seven-fold increase in the capacity of the territory to sustain and become attractive to human populations, which would then lead to migrations from less sustainable lands to Asian Russia during this century,” they say.

Dr Elena Parfenova, from the Krasnoyarsk centre, said: “In a future, warmer climate, food security, in terms of crop distribution and production capability, is predicted to become more favourable to support settlements in what is currently an extremely cold Asian Russia.”

She said that obviously people would flock first to the already developed areas in the south, but most of the area of Siberia and the Far East “have poorly developed infrastructure. The rapidity that these developments occur is dependent on investments in infrastructure and agriculture, which is dependent on the decisions that will be made in the near future.” − Climate News Network

Changing rainfall poses dilemma on dams

A changing climate usually means changing rainfall patterns. And that means a headache for dam builders.

LONDON, 23 May, 2019 − For the builders of hydro-electric schemes – usually multi-billion dollar projects involving vast amounts of complex engineering work – changing rainfall is a serious problem.

With climate change either on the horizon or already happening in many regions of the world, rainfall patterns, on which hydro schemes ultimately depend, are becoming ever more unpredictable.

Christian Rynning-Tonnesen is CEO of Statkraft AS, Norway’s biggest power producer and a major player in the international hydro power business.

In an interview with the Bloomberg news agency, Rynning-Tonnesen says his company has had to double its spending over the last 10 years to reinforce dams in order to cope with heavier rains. He says climate change is hard to ignore when you’re in the hydro-electric business.

“Depending on water as the main source of power in future when we’ll have less of this natural resource looks like an unreliable strategy”

“The general trend all over the world is areas that are dry become more dry and areas that are wet become more wet.”

Norway has seen a 5% rise in rainfall over recent years, says Rynning-Tonnesen.

Others say planning processes behind dam building have to be revised in the face of climate change.

Emilio Moran, a visiting professor at the University of Campinas in São Paulo state in Brazil, says that in one of the world’s biggest hydro-electric building programmes, a total of 147 dams have been planned in the Amazon Basin, with 65 of them in Brazil.

Output fears

In a study published in the Proceedings of the National Academy of Sciences journal, Moran and his co-authors say many of the dams in Brazil − either completed or still in the planning stages − are likely to produce far less power than anticipated, owing to climate variability.

The Amazon Basin is predicted to receive less rainfall and to be hit with higher temperatures in future.

“Depending on water as the main source of power in future when we’ll have less of this natural resource looks like an unreliable strategy”, says Moran.

“To reduce its vulnerability with regard to energy in the context of global climate change, Brazil must diversify its energy mix. It’s still too dependent on hydro-electricity. It needs to invest more in other renewable sources, such as solar, biomass and wind.”

Rainfall drops

Deforestation is expected to create further water shortage problems for hydro plants in the Amazon region. About half the area’s rainfall is due to recycling within the forest.

“Deforestation will, therefore, lead to less precipitation in the region aside from the expected decline due to global climate change”, say the study’s authors.

They say that if the building of large dams in developing countries is to continue, full consideration has to be given to their social impact, the overall cost to the environment and to climate change.

International tensions

In many cases, this doesn’t seem to be happening. Turkey is spending billions on ambitious dam building projects on the Euphrates and Tigris rivers in the south-east of the country. Climate change is predicted to alter the amounts of water available to drive the operation of these dams.

The rivers flow onwards into Syria and Iraq: already water flows downstream are severely reduced at certain times of the year, creating regional tensions and putting in jeopardy the livelihoods of millions dependent on the rivers for drinking water and for agricultural production.

One of the world’s biggest dam projects is in East Africa − the Grand Ethiopian Renaissance Dam (GERD) on the Blue Nile, which flows into the Nile itself. Ethiopia wants to sell electricity generated by the dam to neighbouring countries.

Critics of the GERD project say climate change, including reduced rainfall in the Blue Nile’s catchment area, could seriously affect the dam’s generating capability. − Climate News Network

A changing climate usually means changing rainfall patterns. And that means a headache for dam builders.

LONDON, 23 May, 2019 − For the builders of hydro-electric schemes – usually multi-billion dollar projects involving vast amounts of complex engineering work – changing rainfall is a serious problem.

With climate change either on the horizon or already happening in many regions of the world, rainfall patterns, on which hydro schemes ultimately depend, are becoming ever more unpredictable.

Christian Rynning-Tonnesen is CEO of Statkraft AS, Norway’s biggest power producer and a major player in the international hydro power business.

In an interview with the Bloomberg news agency, Rynning-Tonnesen says his company has had to double its spending over the last 10 years to reinforce dams in order to cope with heavier rains. He says climate change is hard to ignore when you’re in the hydro-electric business.

“Depending on water as the main source of power in future when we’ll have less of this natural resource looks like an unreliable strategy”

“The general trend all over the world is areas that are dry become more dry and areas that are wet become more wet.”

Norway has seen a 5% rise in rainfall over recent years, says Rynning-Tonnesen.

Others say planning processes behind dam building have to be revised in the face of climate change.

Emilio Moran, a visiting professor at the University of Campinas in São Paulo state in Brazil, says that in one of the world’s biggest hydro-electric building programmes, a total of 147 dams have been planned in the Amazon Basin, with 65 of them in Brazil.

Output fears

In a study published in the Proceedings of the National Academy of Sciences journal, Moran and his co-authors say many of the dams in Brazil − either completed or still in the planning stages − are likely to produce far less power than anticipated, owing to climate variability.

The Amazon Basin is predicted to receive less rainfall and to be hit with higher temperatures in future.

“Depending on water as the main source of power in future when we’ll have less of this natural resource looks like an unreliable strategy”, says Moran.

“To reduce its vulnerability with regard to energy in the context of global climate change, Brazil must diversify its energy mix. It’s still too dependent on hydro-electricity. It needs to invest more in other renewable sources, such as solar, biomass and wind.”

Rainfall drops

Deforestation is expected to create further water shortage problems for hydro plants in the Amazon region. About half the area’s rainfall is due to recycling within the forest.

“Deforestation will, therefore, lead to less precipitation in the region aside from the expected decline due to global climate change”, say the study’s authors.

They say that if the building of large dams in developing countries is to continue, full consideration has to be given to their social impact, the overall cost to the environment and to climate change.

International tensions

In many cases, this doesn’t seem to be happening. Turkey is spending billions on ambitious dam building projects on the Euphrates and Tigris rivers in the south-east of the country. Climate change is predicted to alter the amounts of water available to drive the operation of these dams.

The rivers flow onwards into Syria and Iraq: already water flows downstream are severely reduced at certain times of the year, creating regional tensions and putting in jeopardy the livelihoods of millions dependent on the rivers for drinking water and for agricultural production.

One of the world’s biggest dam projects is in East Africa − the Grand Ethiopian Renaissance Dam (GERD) on the Blue Nile, which flows into the Nile itself. Ethiopia wants to sell electricity generated by the dam to neighbouring countries.

Critics of the GERD project say climate change, including reduced rainfall in the Blue Nile’s catchment area, could seriously affect the dam’s generating capability. − Climate News Network

Crops at risk from changing climate

Global warming could bring yet more challenges to a hungry world. New studies have identified precise ways in which a changing climate puts crops at risk.

LONDON, 14 May, 2019 – Climate change is leaving crops at risk. Driven by global warming – and with it ever greater extremes of heat, drought and rainfall – the rising mercury can explain up to half of all variations in harvest yields worldwide.

Unusually cold nights, ever greater numbers of extremely hot summer days, weeks with no rainfall, or torrents of storm-driven precipitation, account for somewhere between a fifth to 49% of yield losses for maize, rice, spring wheat and soy beans.

And once international scientists had eliminated the effect of temperature averages across the whole growing season, they still found that heatwaves, drought and torrential downfall accounted for 18% to 43% of losses.

In a second study, US researchers have a warning for the Midwest’s maize farmers: too much rain is just as bad for the harvest as too much heat and a long dry spell.

“While Africa’s share of global maize production may be small, the largest part of that production goes to human consumption … making it critical for food security”

In a third study, British researchers have identified a new climate hazard for one of the tropical world’s staples: climate change has heightened the risk of a devastating fungal infection that is already ravaging banana plantations in Latin America and the Caribbean.

The impact of climate change driven by global warming fuelled by profligate fossil fuel use had been worrying ministries and agricultural researchers for years: more carbon dioxide should and sometimes could mean a greener world.

More warmth and earlier springs mean a longer growing season with lower risks of late frost. A warmer atmosphere can hold more moisture, which means ultimately more rainfall.

But the average rise in temperature worldwide of just 1°C in the last century is exactly that: an average. What cities and countryside have observed is an increase both in the number and intensity of potentially lethal heatwaves, of longer and more frequent parching in those landscapes that are normally dry, with heavier downpours in places that can depend on reliable rainfall.

Knowledge allows preparation

In Europe, the US and Africa, researchers have started to measure the cost to the grains, pulses and tubers that feed 7.7 billion people now, and will have to feed 9bn later this century.

Scientists in Australia, Germany, Spain, Switzerland and the US report in the journal Environmental Research Letters that they developed a machine-learning algorithm to make sense of climate data and harvest data collected worldwide from 1961 to 2008.

The aim was to isolate the factors within climate change that might affect harvests, on the principle that if farmers know the hazards, they can prepare.

“Interestingly, we found that the most important climate factors for yield anomalies were related to temperature, not precipitation, as one could expect, with average growing season temperature and temperature extremes playing a dominant role in predicting crop yields,” said Elisabeth Vogel of the University of Melbourne, who led the study.

Big picture reached

Nowhere was this more visible than in the figures for maize yield in Africa. “While Africa’s share of global maize production may be small, the largest part of that production goes to human consumption – compared to just 3% in North America – making it critical for food security in the region.”

Dr Vogel and her colleagues looked at crop yields, mean seasonal temperatures, extremes and regions to arrive at their big picture. But impacts of extremes vary according to region, soil, latitude and other factors too.

US scientists report in the journal Global Change Biology that yield statistics and crop insurance data from 1981 to 2016 on the Midwest maize harvest told them a slightly different story. In some years excessive rain reduced the corn yield by as much as 34%; drought and heat in turn could be linked to losses of 37%. It depended on where the crop was grown.

“As rainfall becomes more extreme, crop insurance needs to evolve to better meet planting challenges faced by farmers,” said Gary Schnitkey of the University of Urbana-Champaign, one of the authors.

Bananas in danger

And British scientists report in the Philosophical Transactions of the Royal Society B that changes in temperature and moisture linked to global warming could be bad for the banana crop.

These have increased the risk of infection by the fungus Pseudocercospora fijiensis, or Black Sigatoka disease, by more than 44% in Latin America and the Caribbean. The disease can reduce yield in infected plants by up to 80%.

“Climate change has made temperatures better for spore germination and growth, and made crop canopies wetter, raising the risk of Black Sigatoka infection in many banana-growing areas of Latin America,” said Daniel Bebber, of the University of Exeter.

“While fungus is likely to have been introduced to Honduras on plants imported from Asia for breeding research, our models indicate that climate change over the past 60 years has exacerbated its impact.” – Climate News Network

Global warming could bring yet more challenges to a hungry world. New studies have identified precise ways in which a changing climate puts crops at risk.

LONDON, 14 May, 2019 – Climate change is leaving crops at risk. Driven by global warming – and with it ever greater extremes of heat, drought and rainfall – the rising mercury can explain up to half of all variations in harvest yields worldwide.

Unusually cold nights, ever greater numbers of extremely hot summer days, weeks with no rainfall, or torrents of storm-driven precipitation, account for somewhere between a fifth to 49% of yield losses for maize, rice, spring wheat and soy beans.

And once international scientists had eliminated the effect of temperature averages across the whole growing season, they still found that heatwaves, drought and torrential downfall accounted for 18% to 43% of losses.

In a second study, US researchers have a warning for the Midwest’s maize farmers: too much rain is just as bad for the harvest as too much heat and a long dry spell.

“While Africa’s share of global maize production may be small, the largest part of that production goes to human consumption … making it critical for food security”

In a third study, British researchers have identified a new climate hazard for one of the tropical world’s staples: climate change has heightened the risk of a devastating fungal infection that is already ravaging banana plantations in Latin America and the Caribbean.

The impact of climate change driven by global warming fuelled by profligate fossil fuel use had been worrying ministries and agricultural researchers for years: more carbon dioxide should and sometimes could mean a greener world.

More warmth and earlier springs mean a longer growing season with lower risks of late frost. A warmer atmosphere can hold more moisture, which means ultimately more rainfall.

But the average rise in temperature worldwide of just 1°C in the last century is exactly that: an average. What cities and countryside have observed is an increase both in the number and intensity of potentially lethal heatwaves, of longer and more frequent parching in those landscapes that are normally dry, with heavier downpours in places that can depend on reliable rainfall.

Knowledge allows preparation

In Europe, the US and Africa, researchers have started to measure the cost to the grains, pulses and tubers that feed 7.7 billion people now, and will have to feed 9bn later this century.

Scientists in Australia, Germany, Spain, Switzerland and the US report in the journal Environmental Research Letters that they developed a machine-learning algorithm to make sense of climate data and harvest data collected worldwide from 1961 to 2008.

The aim was to isolate the factors within climate change that might affect harvests, on the principle that if farmers know the hazards, they can prepare.

“Interestingly, we found that the most important climate factors for yield anomalies were related to temperature, not precipitation, as one could expect, with average growing season temperature and temperature extremes playing a dominant role in predicting crop yields,” said Elisabeth Vogel of the University of Melbourne, who led the study.

Big picture reached

Nowhere was this more visible than in the figures for maize yield in Africa. “While Africa’s share of global maize production may be small, the largest part of that production goes to human consumption – compared to just 3% in North America – making it critical for food security in the region.”

Dr Vogel and her colleagues looked at crop yields, mean seasonal temperatures, extremes and regions to arrive at their big picture. But impacts of extremes vary according to region, soil, latitude and other factors too.

US scientists report in the journal Global Change Biology that yield statistics and crop insurance data from 1981 to 2016 on the Midwest maize harvest told them a slightly different story. In some years excessive rain reduced the corn yield by as much as 34%; drought and heat in turn could be linked to losses of 37%. It depended on where the crop was grown.

“As rainfall becomes more extreme, crop insurance needs to evolve to better meet planting challenges faced by farmers,” said Gary Schnitkey of the University of Urbana-Champaign, one of the authors.

Bananas in danger

And British scientists report in the Philosophical Transactions of the Royal Society B that changes in temperature and moisture linked to global warming could be bad for the banana crop.

These have increased the risk of infection by the fungus Pseudocercospora fijiensis, or Black Sigatoka disease, by more than 44% in Latin America and the Caribbean. The disease can reduce yield in infected plants by up to 80%.

“Climate change has made temperatures better for spore germination and growth, and made crop canopies wetter, raising the risk of Black Sigatoka infection in many banana-growing areas of Latin America,” said Daniel Bebber, of the University of Exeter.

“While fungus is likely to have been introduced to Honduras on plants imported from Asia for breeding research, our models indicate that climate change over the past 60 years has exacerbated its impact.” – Climate News Network

Human impact on climate is 100 years old

When did the human impact on climate begin? At least a century ago, with the arrival of the bi-plane, the chauffeur-driven car and the Jazz Age.

LONDON, 2 May, 2019 − Our influence on the Earth’s environment has lasted for a century: the human impact on droughts and moisture patterns began at least 100 years ago, researchers now say.

US scientists used new analytic techniques and almost a thousand years of tree-ring data to build up a picture of drought and rainfall worldwide for the last century. And they report in the journal Nature that they have identified the human fingerprint upon climate variation as far back as the first days of the motor car and the infant aircraft industry.

The pattern of change, in which regions prone to drought such as the western US became more arid, grew visible between 1900 and 1949. The researchers saw the same pattern of drying in those decades in Australia, Europe, the Mediterranean, western Russia and southeast Asia.

At the same time more rain and snow fell in western China, much of central Asia, the Indian subcontinent, Indonesia and central Canada.

Clear signal apparent

Kate Marvel of the Nasa Goddard Institute for Space Studies, who led the research, said: “It’s mind-boggling. There really is a clear signal of the effects of greenhouse gases on the hydroclimate.”

And Benjamin Cook of both the Nasa Institute and the Lamont-Doherty Earth Observatory at Columbia University, said: “We asked, does the real world look like what the models tell us to expect? The answer is yes.

“The big thing we learned is that climate change started affecting global patterns of drought in the early 20th century. We expect this pattern to keep emerging as climate change continues.”

For four decades it has been a given of climate change research that average planetary warming will intensify all the extremes of weather: in particular, drought and flood.

“All the models are projecting that you should see unprecedented drying soon, in a lot of places”

The problem has been that droughts and floods have always happened. But could scientists identify the signature of human change – the clearing of the forests, the intensification of agriculture, the growth of the cities and the ever-increasing use of fossil fuels to dump ever more carbon dioxide in the atmosphere – in any one flood or drought? Until this century, researchers were unwilling to name the guilty party.

No longer. In recent years researchers have done more than just blame overall warming on human activity, and in particular the increasing hazard of extremes of heat, drought and flood.

They have linked human behaviour with drought in California and with record temperatures in 2013 in Australia.

The Nasa-led research is not quite the first to claim to have detected very early evidence of climate change. A team led by Chinese scientists reported in April in the journal Nature Sustainability that tree ring evidence from the Tibetan plateau suggested that humans may have begun altering the pattern of seasonal temperatures – that is, the differences between winter and summer – as early as the 1870s, at least in the northern hemisphere.

Puzzle solved?

But the latest study from Dr Marvel and colleagues identifies such evidence on a wider scale, and may even have resolved the puzzle of the extremes that did not happen.

The research found three distinct periods of change. The first was marked by more drought in some places, more precipitation in others in the first half of the 20th century. But by the height of the Cold War, and the space race mid-century, it became harder to see a pattern, and climate events seemed more random, and climates cooler.

The researchers now think the huge volumes of aerosols from power stations, factory chimneys and vehicle exhausts between 1950 and 1975 altered weather patterns in different ways, affecting cloud formation, rainfall and temperature, to mask the effect of greenhouse gas increases.

These were the years of choking smog, grime and soot, sulphurous droplets, acid rain, corroding historic buildings and urban respiratory disease on an epidemic scale.

Stronger patternn expected

And then developed nations started introducing clean air legislation and other pollution controls. Round about 1981, tentative evidence of the impact of human-driven greenhouse gas emissions began to show again in the climate record, although not as boldly as in the first half of the century.

If the researchers have got it right, the pattern of increasing drought, matched elsewhere by increasing precipitation, will continue to become stronger.

“If we don’t see it coming in stronger in, say, the next 10 years, we might have to wonder whether we are right,” Dr Marvel said. “But all the models are projecting that you should see unprecedented drying soon, in a lot of places.”

And the researchers warn that the consequences for humankind, especially in North America and Eurasia, could be severe. − Climate News Network

When did the human impact on climate begin? At least a century ago, with the arrival of the bi-plane, the chauffeur-driven car and the Jazz Age.

LONDON, 2 May, 2019 − Our influence on the Earth’s environment has lasted for a century: the human impact on droughts and moisture patterns began at least 100 years ago, researchers now say.

US scientists used new analytic techniques and almost a thousand years of tree-ring data to build up a picture of drought and rainfall worldwide for the last century. And they report in the journal Nature that they have identified the human fingerprint upon climate variation as far back as the first days of the motor car and the infant aircraft industry.

The pattern of change, in which regions prone to drought such as the western US became more arid, grew visible between 1900 and 1949. The researchers saw the same pattern of drying in those decades in Australia, Europe, the Mediterranean, western Russia and southeast Asia.

At the same time more rain and snow fell in western China, much of central Asia, the Indian subcontinent, Indonesia and central Canada.

Clear signal apparent

Kate Marvel of the Nasa Goddard Institute for Space Studies, who led the research, said: “It’s mind-boggling. There really is a clear signal of the effects of greenhouse gases on the hydroclimate.”

And Benjamin Cook of both the Nasa Institute and the Lamont-Doherty Earth Observatory at Columbia University, said: “We asked, does the real world look like what the models tell us to expect? The answer is yes.

“The big thing we learned is that climate change started affecting global patterns of drought in the early 20th century. We expect this pattern to keep emerging as climate change continues.”

For four decades it has been a given of climate change research that average planetary warming will intensify all the extremes of weather: in particular, drought and flood.

“All the models are projecting that you should see unprecedented drying soon, in a lot of places”

The problem has been that droughts and floods have always happened. But could scientists identify the signature of human change – the clearing of the forests, the intensification of agriculture, the growth of the cities and the ever-increasing use of fossil fuels to dump ever more carbon dioxide in the atmosphere – in any one flood or drought? Until this century, researchers were unwilling to name the guilty party.

No longer. In recent years researchers have done more than just blame overall warming on human activity, and in particular the increasing hazard of extremes of heat, drought and flood.

They have linked human behaviour with drought in California and with record temperatures in 2013 in Australia.

The Nasa-led research is not quite the first to claim to have detected very early evidence of climate change. A team led by Chinese scientists reported in April in the journal Nature Sustainability that tree ring evidence from the Tibetan plateau suggested that humans may have begun altering the pattern of seasonal temperatures – that is, the differences between winter and summer – as early as the 1870s, at least in the northern hemisphere.

Puzzle solved?

But the latest study from Dr Marvel and colleagues identifies such evidence on a wider scale, and may even have resolved the puzzle of the extremes that did not happen.

The research found three distinct periods of change. The first was marked by more drought in some places, more precipitation in others in the first half of the 20th century. But by the height of the Cold War, and the space race mid-century, it became harder to see a pattern, and climate events seemed more random, and climates cooler.

The researchers now think the huge volumes of aerosols from power stations, factory chimneys and vehicle exhausts between 1950 and 1975 altered weather patterns in different ways, affecting cloud formation, rainfall and temperature, to mask the effect of greenhouse gas increases.

These were the years of choking smog, grime and soot, sulphurous droplets, acid rain, corroding historic buildings and urban respiratory disease on an epidemic scale.

Stronger patternn expected

And then developed nations started introducing clean air legislation and other pollution controls. Round about 1981, tentative evidence of the impact of human-driven greenhouse gas emissions began to show again in the climate record, although not as boldly as in the first half of the century.

If the researchers have got it right, the pattern of increasing drought, matched elsewhere by increasing precipitation, will continue to become stronger.

“If we don’t see it coming in stronger in, say, the next 10 years, we might have to wonder whether we are right,” Dr Marvel said. “But all the models are projecting that you should see unprecedented drying soon, in a lot of places.”

And the researchers warn that the consequences for humankind, especially in North America and Eurasia, could be severe. − Climate News Network

Heat makes ocean winds and waves fiercer

The seas are rising. Ocean winds and waves are growing in speed and force. The oceans could be feeling the heat.

LONDON, 1 May, 2019 − The great swells of the Pacific are beginning to swell even more as fiercer ocean winds and waves leave their mark. The breakers that crash on the storm beaches now do so with greater force. The white horses are gathering pace.

A 33-year-study of data from 31 satellites and 80 ocean buoys has confirmed suspicions. The extreme ocean winds are now fiercer, and the waves are getting measurably higher.

It is a given of global warming that as average planetary temperatures rise, then more energy is available for storm, rainfall and drought.

In the past century, because of ever-increasing combustion of fossil fuels that release growing quantities of greenhouse gases, average global temperatures have crept higher by 1°C and in three decades the speed of extreme winds in the Southern Ocean has increased by 8%, or 1.5 metres per second. Extreme waves have increased by 30cms, or 5%, over the same period.

“These changes have impacts that are felt all over the world. Storm waves can increase coastal erosion, putting coastal settlements and infrastructures at risk”

“Although increases of 5 and 8% might not seem like much, if sustained into the future such changes to our climate will have major impacts,” said Ian Young, an engineer at the University of Melbourne in Australia

He and a colleague report in the journal Science that they reached their conclusion on the basis of 4 billion observations made between 1985 and 2018.

“Flooding events are caused by storm surge and associated breaking waves. The increased sea level makes these events more serious and more frequent,” said Professor Young. “Increases in wave height, and changes in other properties such as wave direction, will further increase the probability of coastal flooding.”

Sea levels have been creeping ever higher, in large part because of the retreat of most of the planet’s great glaciers and the ever-increasing meltwater from Greenland and West Antarctica, and also as a simple matter of physics: as the oceans warm, the waters become less dense and sea levels rise.

Difficult measurements

Surfers and pleasure-seekers began to worry about the impact of global warming and climate change on wave patterns years ago. But seemingly simple phenomena such as the effects wave height and wind speed have in the open oceans on a world-wide basis are harder to measure.

Spanish oceanographers reported earlier this year that they were sure that ocean waves were gathering in force and strength, and European engineers have warned of the impact of more intense storms backed up by rising seas on the Atlantic ports and coastlines of the continent.

But there are problems: precision measurements have been made only recently. Oceanographers cannot be sure that they are not witnessing a natural cycle of ocean change, in which storm intensities slowly vary over a pattern of decades.

Since 1985 earth observation satellites have been equipped with altimeters to measure wave height and wind speed, radiometers to measure wind speed, and scatterometers to record wind speed and direction. The next problem has been calibrating data from a range of different satellites, and indeed the slightly different stories told by instruments on the same satellite.

Worse to come

But the Australian engineers report that they are now 90% confident that they can measure ocean change: violent storms now arrive with higher wave crests and more dangerous winds than they did in 1985, and although this is true worldwide, the effect is most pronounced in the great ocean that swirls around Antarctica.

The next challenge is to make estimates of how much more violent the worst sea storms are likely to become later in the century, as planetary average temperatures – and sea levels – continue to rise.

“These changes have impacts that are felt all over the world. Storm waves can increase coastal erosion, putting coastal settlements and infrastructures at risk,” Professor Young said.

“We need a better understanding of how much this change is due to long-term climate change, and how much is due to multi-decadal fluctuations or cycles.” − Climate News Network

The seas are rising. Ocean winds and waves are growing in speed and force. The oceans could be feeling the heat.

LONDON, 1 May, 2019 − The great swells of the Pacific are beginning to swell even more as fiercer ocean winds and waves leave their mark. The breakers that crash on the storm beaches now do so with greater force. The white horses are gathering pace.

A 33-year-study of data from 31 satellites and 80 ocean buoys has confirmed suspicions. The extreme ocean winds are now fiercer, and the waves are getting measurably higher.

It is a given of global warming that as average planetary temperatures rise, then more energy is available for storm, rainfall and drought.

In the past century, because of ever-increasing combustion of fossil fuels that release growing quantities of greenhouse gases, average global temperatures have crept higher by 1°C and in three decades the speed of extreme winds in the Southern Ocean has increased by 8%, or 1.5 metres per second. Extreme waves have increased by 30cms, or 5%, over the same period.

“These changes have impacts that are felt all over the world. Storm waves can increase coastal erosion, putting coastal settlements and infrastructures at risk”

“Although increases of 5 and 8% might not seem like much, if sustained into the future such changes to our climate will have major impacts,” said Ian Young, an engineer at the University of Melbourne in Australia

He and a colleague report in the journal Science that they reached their conclusion on the basis of 4 billion observations made between 1985 and 2018.

“Flooding events are caused by storm surge and associated breaking waves. The increased sea level makes these events more serious and more frequent,” said Professor Young. “Increases in wave height, and changes in other properties such as wave direction, will further increase the probability of coastal flooding.”

Sea levels have been creeping ever higher, in large part because of the retreat of most of the planet’s great glaciers and the ever-increasing meltwater from Greenland and West Antarctica, and also as a simple matter of physics: as the oceans warm, the waters become less dense and sea levels rise.

Difficult measurements

Surfers and pleasure-seekers began to worry about the impact of global warming and climate change on wave patterns years ago. But seemingly simple phenomena such as the effects wave height and wind speed have in the open oceans on a world-wide basis are harder to measure.

Spanish oceanographers reported earlier this year that they were sure that ocean waves were gathering in force and strength, and European engineers have warned of the impact of more intense storms backed up by rising seas on the Atlantic ports and coastlines of the continent.

But there are problems: precision measurements have been made only recently. Oceanographers cannot be sure that they are not witnessing a natural cycle of ocean change, in which storm intensities slowly vary over a pattern of decades.

Since 1985 earth observation satellites have been equipped with altimeters to measure wave height and wind speed, radiometers to measure wind speed, and scatterometers to record wind speed and direction. The next problem has been calibrating data from a range of different satellites, and indeed the slightly different stories told by instruments on the same satellite.

Worse to come

But the Australian engineers report that they are now 90% confident that they can measure ocean change: violent storms now arrive with higher wave crests and more dangerous winds than they did in 1985, and although this is true worldwide, the effect is most pronounced in the great ocean that swirls around Antarctica.

The next challenge is to make estimates of how much more violent the worst sea storms are likely to become later in the century, as planetary average temperatures – and sea levels – continue to rise.

“These changes have impacts that are felt all over the world. Storm waves can increase coastal erosion, putting coastal settlements and infrastructures at risk,” Professor Young said.

“We need a better understanding of how much this change is due to long-term climate change, and how much is due to multi-decadal fluctuations or cycles.” − Climate News Network

Cloud forests risk drying out by 2060

For the world’s cloud forests, the future is overcast. Some face fiercer storm and flood: they could even lose their unique clouds.

LONDON, 23 April, 2019 – Planet Earth may be about to lose a whole ecosystem: the cloud forests – those species-rich, high altitude rainforests found mostly in Central and South America – could be all but gone in 40 years.

Researchers warn that within 25 years, global warming driven by ever increasing use of fossil fuels could dry up 60-80% of the misty mountain forests of Mexico, Puerto Rico, Costa Rica, Ecuador and Peru, simply by dispersing the clouds that keep them ever moist, and rich with plant, insect and bird life.

And as the habitat alters, that could be it for the Monarch butterflies that migrate in their millions to the mountains of Mexico, the elfin woods warbler found only in Puerto Rico, and the other creatures that make their homes in forests so rich and wet that even the trees are home to yet more green habitat: ferns, lichens, mosses and other epiphytes nourished by year-round water and water vapour.

And the reason? The clouds will have dispersed, or moved uphill, or simply been blown away as greenhouse gas ratios in the atmosphere continue to grow and temperatures creep ever higher, according to new research in the Public Library of Science journal PLOS One.

“Maria is more extreme in its precipitation than anything else the island has ever seen. I just didn’t expect that it was going to be so much more than anything else that has happened in the last 60 years”

And if nations go on burning ever greater quantities of coal, oil and natural gas to power economic growth, then the cloud and frost that keep the equatorial cloud forests unique homes to living things will have gone.

Nine-tenths of the cloud forests in the Western Hemisphere will have been lost by 2060, if the calculations funded by the US Department of Agriculture’s Forest Service are correct.

Researchers mapped cloud forest across the Western Hemisphere with data collected over the last 60 years and then used climate simulations to see how the habitat would change with time.

They found that indeed some regions would become even more immersed in cloud: this however would only add up to perhaps 1%. For the most part the clouds would thin, the steady supply of moisture would thin, and the forests would begin to change inexorably.

Trees head uphill

This is not the first research to suggest that ever higher temperatures would affect cloud patterns. Scientists using a different approach reported earlier this year that tropical cloud formation of the kind that damps down equatorial temperatures could be at risk.

Other researchers have used historic data to record the steady uphill march of characteristic trees in the Andean forests in response to average global temperature increases of 1°C in the past century.

And yet another team has warned that the increasingly violent winds that arrived in Puerto Rico with Hurricane Maria in 2017 would in any case change the make-up of forest species.

Devastating winds that uproot forest giants at all altitudes won’t be the only problem for the climate-hit forests and the region. Hurricane Maria dumped an unprecedented 1.029 mm of rain in a day on Puerto Rico.

Recurrence likely

A second study from the American Geophysical Union has confirmed that the extreme rainfall that accompanied Maria was not only the worst in the last 60 years, but has become much more likely to happen again.

Thanks to global warming, which increased the capacity of the atmosphere to absorb moisture, such floods are now five times more likely, they write in the journal Geophysical Research Letters.

“Maria is more extreme in its precipitation than anything else the island has ever seen,” said David Keellings of the University of Alabama, one of the authors.

“I just didn’t expect that it was going to be so much more than anything else that has happened in the last 60 years.” – Climate News Network

For the world’s cloud forests, the future is overcast. Some face fiercer storm and flood: they could even lose their unique clouds.

LONDON, 23 April, 2019 – Planet Earth may be about to lose a whole ecosystem: the cloud forests – those species-rich, high altitude rainforests found mostly in Central and South America – could be all but gone in 40 years.

Researchers warn that within 25 years, global warming driven by ever increasing use of fossil fuels could dry up 60-80% of the misty mountain forests of Mexico, Puerto Rico, Costa Rica, Ecuador and Peru, simply by dispersing the clouds that keep them ever moist, and rich with plant, insect and bird life.

And as the habitat alters, that could be it for the Monarch butterflies that migrate in their millions to the mountains of Mexico, the elfin woods warbler found only in Puerto Rico, and the other creatures that make their homes in forests so rich and wet that even the trees are home to yet more green habitat: ferns, lichens, mosses and other epiphytes nourished by year-round water and water vapour.

And the reason? The clouds will have dispersed, or moved uphill, or simply been blown away as greenhouse gas ratios in the atmosphere continue to grow and temperatures creep ever higher, according to new research in the Public Library of Science journal PLOS One.

“Maria is more extreme in its precipitation than anything else the island has ever seen. I just didn’t expect that it was going to be so much more than anything else that has happened in the last 60 years”

And if nations go on burning ever greater quantities of coal, oil and natural gas to power economic growth, then the cloud and frost that keep the equatorial cloud forests unique homes to living things will have gone.

Nine-tenths of the cloud forests in the Western Hemisphere will have been lost by 2060, if the calculations funded by the US Department of Agriculture’s Forest Service are correct.

Researchers mapped cloud forest across the Western Hemisphere with data collected over the last 60 years and then used climate simulations to see how the habitat would change with time.

They found that indeed some regions would become even more immersed in cloud: this however would only add up to perhaps 1%. For the most part the clouds would thin, the steady supply of moisture would thin, and the forests would begin to change inexorably.

Trees head uphill

This is not the first research to suggest that ever higher temperatures would affect cloud patterns. Scientists using a different approach reported earlier this year that tropical cloud formation of the kind that damps down equatorial temperatures could be at risk.

Other researchers have used historic data to record the steady uphill march of characteristic trees in the Andean forests in response to average global temperature increases of 1°C in the past century.

And yet another team has warned that the increasingly violent winds that arrived in Puerto Rico with Hurricane Maria in 2017 would in any case change the make-up of forest species.

Devastating winds that uproot forest giants at all altitudes won’t be the only problem for the climate-hit forests and the region. Hurricane Maria dumped an unprecedented 1.029 mm of rain in a day on Puerto Rico.

Recurrence likely

A second study from the American Geophysical Union has confirmed that the extreme rainfall that accompanied Maria was not only the worst in the last 60 years, but has become much more likely to happen again.

Thanks to global warming, which increased the capacity of the atmosphere to absorb moisture, such floods are now five times more likely, they write in the journal Geophysical Research Letters.

“Maria is more extreme in its precipitation than anything else the island has ever seen,” said David Keellings of the University of Alabama, one of the authors.

“I just didn’t expect that it was going to be so much more than anything else that has happened in the last 60 years.” – Climate News Network

Half a degree may make heat impact far worse

Half a degree of warming doesn’t sound like much. But there is fresh evidence that it could make a huge difference to rainfall and drought.

LONDON, 4 April, 2019 − Japanese scientists have found new evidence that a global average temperature rise as small as half a degree could have a drastic effect.

They conclude that the world cannot afford to delay action to reduce greenhouse gas emissions and slow global warming to 1.5°C by 2100 – the “ideal target” enshrined in the promise by 195 nations to limit warming to well below 2°C above the long-term average for most of human history.

The evidence is this: a shift of even 0.5°C could make a dramatic difference to the risks of devastating droughts and calamitous floods.

If governments keep to the letter of the Paris Agreement of 2015 but not the spirit, and let warming rise to the maximum of 2°, then there will be more intense rainfall across North America, Europe and Asia, and more intense droughts around the Mediterranean.

And although the average intensity of each flood or drought would increase measurably, the intensity of the most extreme event could be even more intense: 10 times greater. That is: the worst imaginable floods 80 years from now would be ten times worse than the worst today.

“Such drastic changes between flood and drought conditions pose a major challenge . . . risks could be substantially reduced by achieving a 1.5°C target”

At the heart of research like this is a new way of looking at future climate projections devised – by researchers all over the world – on a range of possible outcomes for a planet that has recognised climate change, vowed to respond, but failed to take sufficiently energetic steps.

The planet is already warmer by 1°C on average than it was a century ago. Since the Paris Agreement researchers have warned that on present form, and with the present state of commitment nationally and internationally, global average temperatures will top an increase of at least 3°C by the century’s close.

This would be catastrophic. But since then, a slew of fresh studies has defined fresh shades of potential catastrophe even at 2°C maximum, and delivered evidence that a limit of overall warming to the target of 1.5°C would save not just economic damage but even lost lands.

They have demonstrated that just half a degree more would see sea levels rise by 10cms, to threaten the existence of already vulnerable small island states and low-lying coastal floodplains, to put at risk the survival of the coral reefs, and the Arctic ice.

The latest study simply addressed a phenomenon known in the scientific language as the event-to-event hydrological intensification index. This awkward mouthful of syllables masks the crude consequence of average warming: if the overall temperature rises, then so do the extremes of temperature. That is what is meant by average: the mean of all the extremes.

Harder rain

But if average temperatures rise, so does the capacity of the air to hold moisture, which means that when it does rain, then it will rain harder. And when it doesn’t, the groundwater will evaporate more easily.

So landscapes such as the US south-west, already prone to heat and drought, can expect more heat waves, more forest fires and more intense and prolonged drought, while the northeast could see more flooding.

And the latest study in the journal Scientific Reports, by researchers at the University of Tokyo, looked at the difference of outcomes between 1.5°C and 2°C in an already rapidly-warming world, to find that when it came to rainfall – and the attendant floods, droughts, mudslides, harvest failures and water shortages – even half a degree beyond the ideal could make the very bad 10 times worse.

“The high damage potential of such drastic changes between flood and drought conditions poses a major challenge to adaptation,” the researchers conclude, “and the findings suggest that risks could be substantially reduced by achieving a 1.5°C target.” − Climate News Network

Half a degree of warming doesn’t sound like much. But there is fresh evidence that it could make a huge difference to rainfall and drought.

LONDON, 4 April, 2019 − Japanese scientists have found new evidence that a global average temperature rise as small as half a degree could have a drastic effect.

They conclude that the world cannot afford to delay action to reduce greenhouse gas emissions and slow global warming to 1.5°C by 2100 – the “ideal target” enshrined in the promise by 195 nations to limit warming to well below 2°C above the long-term average for most of human history.

The evidence is this: a shift of even 0.5°C could make a dramatic difference to the risks of devastating droughts and calamitous floods.

If governments keep to the letter of the Paris Agreement of 2015 but not the spirit, and let warming rise to the maximum of 2°, then there will be more intense rainfall across North America, Europe and Asia, and more intense droughts around the Mediterranean.

And although the average intensity of each flood or drought would increase measurably, the intensity of the most extreme event could be even more intense: 10 times greater. That is: the worst imaginable floods 80 years from now would be ten times worse than the worst today.

“Such drastic changes between flood and drought conditions pose a major challenge . . . risks could be substantially reduced by achieving a 1.5°C target”

At the heart of research like this is a new way of looking at future climate projections devised – by researchers all over the world – on a range of possible outcomes for a planet that has recognised climate change, vowed to respond, but failed to take sufficiently energetic steps.

The planet is already warmer by 1°C on average than it was a century ago. Since the Paris Agreement researchers have warned that on present form, and with the present state of commitment nationally and internationally, global average temperatures will top an increase of at least 3°C by the century’s close.

This would be catastrophic. But since then, a slew of fresh studies has defined fresh shades of potential catastrophe even at 2°C maximum, and delivered evidence that a limit of overall warming to the target of 1.5°C would save not just economic damage but even lost lands.

They have demonstrated that just half a degree more would see sea levels rise by 10cms, to threaten the existence of already vulnerable small island states and low-lying coastal floodplains, to put at risk the survival of the coral reefs, and the Arctic ice.

The latest study simply addressed a phenomenon known in the scientific language as the event-to-event hydrological intensification index. This awkward mouthful of syllables masks the crude consequence of average warming: if the overall temperature rises, then so do the extremes of temperature. That is what is meant by average: the mean of all the extremes.

Harder rain

But if average temperatures rise, so does the capacity of the air to hold moisture, which means that when it does rain, then it will rain harder. And when it doesn’t, the groundwater will evaporate more easily.

So landscapes such as the US south-west, already prone to heat and drought, can expect more heat waves, more forest fires and more intense and prolonged drought, while the northeast could see more flooding.

And the latest study in the journal Scientific Reports, by researchers at the University of Tokyo, looked at the difference of outcomes between 1.5°C and 2°C in an already rapidly-warming world, to find that when it came to rainfall – and the attendant floods, droughts, mudslides, harvest failures and water shortages – even half a degree beyond the ideal could make the very bad 10 times worse.

“The high damage potential of such drastic changes between flood and drought conditions poses a major challenge to adaptation,” the researchers conclude, “and the findings suggest that risks could be substantially reduced by achieving a 1.5°C target.” − Climate News Network