Tag Archives: Wildfires

Smoke from wildfires kills thousands annually

Smoke from wildfires, linked to climate, grows daily more of a threat. Now science can see the direct human health cost.

LONDON, 14 September, 2021− Smoke from wildfires in burning forest vegetation now claims at least 33,500 lives a year worldwide. And that’s based on data from just 749 cities in 43 countries during the years 2000 to 2016.

The true cost to humankind of wildfire pollution from tiny particles of incinerated vegetation in cardiovascular and respiratory deaths will inevitably be much larger.

And a separate study finds that the fires now blazing every year in the Brazilian Amazon send more than 48,000 Brazilians to hospital. In the same timespan − the first 15 years of this century − an estimated 755,091 Brazilians have been admitted to hospitals with respiratory and cardiovascular conditions triggered by wildfire pollution.

Both findings are based on the use of subtle statistical techniques to tease out from public records the direct causes of hospitalisation and death. In the first study, researchers report in the journal Lancet Planetary Health that they combed through records of more than 66 million deaths from all causes in a selection of cities from 43 nations and regions, and then applied sophisticated mathematics to calculate which cases would have been triggered by the inhalation of what health scientists called “fine particulate matter” − fine enough to enter the lungs, cross the walls of the lung tissue and enter the blood circulation.

Wildfire smoke is deadlier than most forms of atmospheric pollution: it’s made up of smaller particles of a different chemical composition forged in higher temperatures. It can also travel further, up to 1,000 kms (625 miles), and still be potentially sickening.

Urban penalty

And, in a world in which planetary temperatures are soaring, droughts are becoming more intense and more frequent, and human destruction of the forests more devastating, the potential dangers are increasing.

California in 2020 recorded more than 46,000 outbreaks of wildfire. In the 2019-2020 burning season, Australia lost more than 100,000 sq kms of bush, forest and parkland to wildfire.

Brazil’s Amazon forest, disfigured by an accelerating number of fire outbreaks in the last two years, has lost more than 33,000 sq kms of canopy to fire every year since 2003.

A second study in the same journal identifies the cost across the decades to the nation with the largest and most important tropical forest on the planet: Brazil.

The fires may burn in distant regions now being converted to cattle ranches, soy plantations or mining operations, but the price is paid in crowded cities.

“In a world in which planetary temperatures are soaring and human destruction of the forests more devastating, the potential dangers are increasing”

Toxic smoke from these wildfires in the Amazon region can rise to enormous heights and travel colossal distances to trigger asthma, heart attack, stroke, respiratory conditions, hospitalisation and death, in young children and the elderly in particular.

The Lancet is one of the world’s oldest and most prestige-laden medical journals: it has also paid close attention to the health costs linked in any way to climate change driven by profligate greenhouse gas emissions, as the use of fossil fuels continues to expand.

It and its sister publications have examined the global hazard to new-born children in a fast-warming world; the massive global death toll of ever-increasing extremes of heat and cold; the health costs in terms of hunger and malnutrition that will follow as harvests wither, and as energy, protein and mineral levels in staple foods begin to change with ever-higher temperatures; and even to the direct consequences to the workforce and the economy as extreme temperatures begin to rise to unprecedented levels.

So the latest finding is in part a warning to governments, municipalities, nations and above all health professionals to be prepared for greater levels of hospitalisation and death.

Although one study is a worldwide look, the second a closer look at the costs to just one nation, the problem is truly worldwide: Japan, according to data from 47 cities, loses 7,000 people a year to wildfire pollution; Mexico (10 cities) more than 3,000; and the US records more than 3,200 deaths in 210 cities each year. − Climate News Network

Smoke from wildfires, linked to climate, grows daily more of a threat. Now science can see the direct human health cost.

LONDON, 14 September, 2021− Smoke from wildfires in burning forest vegetation now claims at least 33,500 lives a year worldwide. And that’s based on data from just 749 cities in 43 countries during the years 2000 to 2016.

The true cost to humankind of wildfire pollution from tiny particles of incinerated vegetation in cardiovascular and respiratory deaths will inevitably be much larger.

And a separate study finds that the fires now blazing every year in the Brazilian Amazon send more than 48,000 Brazilians to hospital. In the same timespan − the first 15 years of this century − an estimated 755,091 Brazilians have been admitted to hospitals with respiratory and cardiovascular conditions triggered by wildfire pollution.

Both findings are based on the use of subtle statistical techniques to tease out from public records the direct causes of hospitalisation and death. In the first study, researchers report in the journal Lancet Planetary Health that they combed through records of more than 66 million deaths from all causes in a selection of cities from 43 nations and regions, and then applied sophisticated mathematics to calculate which cases would have been triggered by the inhalation of what health scientists called “fine particulate matter” − fine enough to enter the lungs, cross the walls of the lung tissue and enter the blood circulation.

Wildfire smoke is deadlier than most forms of atmospheric pollution: it’s made up of smaller particles of a different chemical composition forged in higher temperatures. It can also travel further, up to 1,000 kms (625 miles), and still be potentially sickening.

Urban penalty

And, in a world in which planetary temperatures are soaring, droughts are becoming more intense and more frequent, and human destruction of the forests more devastating, the potential dangers are increasing.

California in 2020 recorded more than 46,000 outbreaks of wildfire. In the 2019-2020 burning season, Australia lost more than 100,000 sq kms of bush, forest and parkland to wildfire.

Brazil’s Amazon forest, disfigured by an accelerating number of fire outbreaks in the last two years, has lost more than 33,000 sq kms of canopy to fire every year since 2003.

A second study in the same journal identifies the cost across the decades to the nation with the largest and most important tropical forest on the planet: Brazil.

The fires may burn in distant regions now being converted to cattle ranches, soy plantations or mining operations, but the price is paid in crowded cities.

“In a world in which planetary temperatures are soaring and human destruction of the forests more devastating, the potential dangers are increasing”

Toxic smoke from these wildfires in the Amazon region can rise to enormous heights and travel colossal distances to trigger asthma, heart attack, stroke, respiratory conditions, hospitalisation and death, in young children and the elderly in particular.

The Lancet is one of the world’s oldest and most prestige-laden medical journals: it has also paid close attention to the health costs linked in any way to climate change driven by profligate greenhouse gas emissions, as the use of fossil fuels continues to expand.

It and its sister publications have examined the global hazard to new-born children in a fast-warming world; the massive global death toll of ever-increasing extremes of heat and cold; the health costs in terms of hunger and malnutrition that will follow as harvests wither, and as energy, protein and mineral levels in staple foods begin to change with ever-higher temperatures; and even to the direct consequences to the workforce and the economy as extreme temperatures begin to rise to unprecedented levels.

So the latest finding is in part a warning to governments, municipalities, nations and above all health professionals to be prepared for greater levels of hospitalisation and death.

Although one study is a worldwide look, the second a closer look at the costs to just one nation, the problem is truly worldwide: Japan, according to data from 47 cities, loses 7,000 people a year to wildfire pollution; Mexico (10 cities) more than 3,000; and the US records more than 3,200 deaths in 210 cities each year. − Climate News Network

Fire and flood menace parts of US and Bangladesh

Fire and flood are on the rise. Bangladesh and New York face more flooding: the American West may see more forests burn.

LONDON, 14 December, 2020 − More extreme weather is on the way for the hapless residents of Bangladesh, New York and the western US,  facing the prospect of worsening fire and flood.

There is a new future for New York. By the close of the century, thanks to sea level rise and global heating, parts of it could be swept by hurricane-driven catastrophic floods almost every year.

Things don’t look much brighter for much of Bangladesh. Scientists have recalculated the risk of flooding by the Brahmaputra river system to find that, even without the climate emergency, they had under-estimated the likelihood of devastating floods across the crowded, low-lying landscape.

And far away in the American west, US citizens face yet more and more devastating seasons of fire. The area incinerated by severe fires has increased eight-fold in the last 40 years, thanks to intensifying heat and drought. And thanks to climate change, drought will become more extended and more frequent. The temperatures, too, will go on rising.

All this emerged in just another week of routine climate science, as researchers try to gauge the difficulties to come, for national and civic authorities, for foresters and for farmers.

“The increase in these once-in-a-generation floods is so dramatic because the impact of sea-level rise will create greater flooding, even if the storms today stay the same”

In 2012, Hurricane Sandy hit the US to cause $70bn in damages, and even slammed unexpectedly into New York, to devastate parts of the city. It counted as a once-in-500 years event.

Researchers report in the journal Climatic Change that they looked at the probabilities of more flooding in Jamaica Bay, on Long Island, New York as sea levels rose, along with the sea surface temperatures that drive fiercer storm weather, through the century.

Floods that tend to happen every century could, by 2050, occur every nine years. By 2080 to 2100, they could become annual events. And 500-year events like the 2012 superstorm could by the end of the century happen perhaps once every four years.

“Future projections of the hurricane climatology suggest that climate change would lead to storms that move more slowly and are more intense than we have ever seen before hitting Jamaica Bay,” said Reza Marsooli, an environmental engineer at the Stevens Institute of Technology in Hoboken, New Jersey, a co-author.

“But the increase in these once-in-a-generation or even less frequent floods is so dramatic because the impact of sea-level rise will create greater flooding, even if the storms we are seeing today stayed the same.”

Prepare for worse

The hazard that faces Bangladesh − much of which is at sea level, on fertile floodplain created by the Ganges-Brahmaputra river system − is more insidious.

One of the great waterways of the world, it rises in the Himalayan snows and swells in the monsoon season to flood the rice paddies and replenish farmlands with nourishing sediments. Occasionally the floods become devastating: in 1998, some 70% of the nation was submerged. Floods have recurred, in 2007, 2010 and 2020.

Engineers have been monitoring the flow since the 1950s, and thought they knew the flood probabilities. But US, Australian and Chinese scientists report in the journal Nature Communications that they studied the growth rings in ancient trees to find that Bangladeshis have been living in unusual times: for much of the past 70 years, on the evidence told by old trees along the watershed, the river flow has been unusually dry − the driest in the last 700 years.

“The tree rings suggest that the long-term baseline conditions are much wetter than thought,” said Mukund Palat Rao, of the Lamont-Doherty Earth Observatory at Columbia University in New York, who led the research.

“Whether you consider climate models or natural variability, the message is the same. We should prepare for a higher frequency of flooding than we are currently predicting.”

Forests’ future threatened

In the past 40 years, thanks to global heating driven by ever-higher emissions of greenhouse gases from the combustion of fossil fuels, the state of California has experienced a series of droughts that lasted for years. The fire season too has begun earlier and lasted much longer.

Ecologists report in the journal Geophysical Research Letters that they defined high-severity fires as those that killed 95% of all trees. They then counted the most severe episodes of burning in four great regions of the western US from 1985 to 2017.

They found that by 2017, the area wiped out by severe fires had risen eight times, to more than 2,000 sq kms or 800 sq miles. Much of the tree cover of the US west is adapted to episodes of fire. But the frequency and intensity of recent blazes threatens the future of the forests altogether.

“As more area burns at high severity, the likelihood of conversion to different forest types or even to non-forest increases,” said Sean Parks of the US Forest Service Rocky Mountain Research Station, and the lead author.

“At the same time, the post-fire climate is making it increasingly difficult for seedlings to establish and survive, further reducing the potential for forests to return to their pre-fire condition.” − Climate News Network

Fire and flood are on the rise. Bangladesh and New York face more flooding: the American West may see more forests burn.

LONDON, 14 December, 2020 − More extreme weather is on the way for the hapless residents of Bangladesh, New York and the western US,  facing the prospect of worsening fire and flood.

There is a new future for New York. By the close of the century, thanks to sea level rise and global heating, parts of it could be swept by hurricane-driven catastrophic floods almost every year.

Things don’t look much brighter for much of Bangladesh. Scientists have recalculated the risk of flooding by the Brahmaputra river system to find that, even without the climate emergency, they had under-estimated the likelihood of devastating floods across the crowded, low-lying landscape.

And far away in the American west, US citizens face yet more and more devastating seasons of fire. The area incinerated by severe fires has increased eight-fold in the last 40 years, thanks to intensifying heat and drought. And thanks to climate change, drought will become more extended and more frequent. The temperatures, too, will go on rising.

All this emerged in just another week of routine climate science, as researchers try to gauge the difficulties to come, for national and civic authorities, for foresters and for farmers.

“The increase in these once-in-a-generation floods is so dramatic because the impact of sea-level rise will create greater flooding, even if the storms today stay the same”

In 2012, Hurricane Sandy hit the US to cause $70bn in damages, and even slammed unexpectedly into New York, to devastate parts of the city. It counted as a once-in-500 years event.

Researchers report in the journal Climatic Change that they looked at the probabilities of more flooding in Jamaica Bay, on Long Island, New York as sea levels rose, along with the sea surface temperatures that drive fiercer storm weather, through the century.

Floods that tend to happen every century could, by 2050, occur every nine years. By 2080 to 2100, they could become annual events. And 500-year events like the 2012 superstorm could by the end of the century happen perhaps once every four years.

“Future projections of the hurricane climatology suggest that climate change would lead to storms that move more slowly and are more intense than we have ever seen before hitting Jamaica Bay,” said Reza Marsooli, an environmental engineer at the Stevens Institute of Technology in Hoboken, New Jersey, a co-author.

“But the increase in these once-in-a-generation or even less frequent floods is so dramatic because the impact of sea-level rise will create greater flooding, even if the storms we are seeing today stayed the same.”

Prepare for worse

The hazard that faces Bangladesh − much of which is at sea level, on fertile floodplain created by the Ganges-Brahmaputra river system − is more insidious.

One of the great waterways of the world, it rises in the Himalayan snows and swells in the monsoon season to flood the rice paddies and replenish farmlands with nourishing sediments. Occasionally the floods become devastating: in 1998, some 70% of the nation was submerged. Floods have recurred, in 2007, 2010 and 2020.

Engineers have been monitoring the flow since the 1950s, and thought they knew the flood probabilities. But US, Australian and Chinese scientists report in the journal Nature Communications that they studied the growth rings in ancient trees to find that Bangladeshis have been living in unusual times: for much of the past 70 years, on the evidence told by old trees along the watershed, the river flow has been unusually dry − the driest in the last 700 years.

“The tree rings suggest that the long-term baseline conditions are much wetter than thought,” said Mukund Palat Rao, of the Lamont-Doherty Earth Observatory at Columbia University in New York, who led the research.

“Whether you consider climate models or natural variability, the message is the same. We should prepare for a higher frequency of flooding than we are currently predicting.”

Forests’ future threatened

In the past 40 years, thanks to global heating driven by ever-higher emissions of greenhouse gases from the combustion of fossil fuels, the state of California has experienced a series of droughts that lasted for years. The fire season too has begun earlier and lasted much longer.

Ecologists report in the journal Geophysical Research Letters that they defined high-severity fires as those that killed 95% of all trees. They then counted the most severe episodes of burning in four great regions of the western US from 1985 to 2017.

They found that by 2017, the area wiped out by severe fires had risen eight times, to more than 2,000 sq kms or 800 sq miles. Much of the tree cover of the US west is adapted to episodes of fire. But the frequency and intensity of recent blazes threatens the future of the forests altogether.

“As more area burns at high severity, the likelihood of conversion to different forest types or even to non-forest increases,” said Sean Parks of the US Forest Service Rocky Mountain Research Station, and the lead author.

“At the same time, the post-fire climate is making it increasingly difficult for seedlings to establish and survive, further reducing the potential for forests to return to their pre-fire condition.” − Climate News Network

Australian forests’ smoke climbed 20 miles in 2019

Blazing Australian forests made their mark high in the stratosphere and cast a cloud that lingered for months.

LONDON, 4 November, 2020 − Australian forests, devoured by devastating wildfires in the last southern hemisphere summer, set a new high − a huge smoke cloud that soared more than 20 miles into the upper atmosphere and stayed there for months.

An international team of scientists reports in the Nature journal Communications Earth and Environment that they tracked the cloud to an altitude of 35 kilometres (21 miles).

They measured it as 1,000 kms (625 miles) across. They followed it around the planet for 66,000 kms (41,010 miles). And they confirm that it remained intact for three months.

This high-flying pollution wasn’t the first such instance: just three times the size of any observed predecessor. Until now the record was held by plumes soaring from forest fires in western Canada in 2017.

Growing intensity

“When I saw the satellite measurement of the smoke plume at 35 kms, it was jaw-dropping. I never would have expected that”, said Adam Bourassa of the University of Saskatchewan in Canada, one of the researchers.

“We’re seeing records broken in terms of the impact on the atmosphere from these fires. Knowing that they’re likely to strike more frequently and with more intensity due to climate change, we could end up with a pretty dramatically changed atmosphere.”

A blaze that can make a new cloud 35 kms above its surface is an indicator both of the potential devastation of climate change driven by profligate human use of fossil fuels and of the intricate workings of the biosphere and atmosphere.

After months of desperate drought in 2019, eastern Australia effectively caught fire. Around 110,000 sq kms of bush, forest and grassland went up in smoke: with them went thousands of homes and millions of wild and domestic animals. Altogether 33 people died.

“We’re seeing records broken in terms of the impact on the atmosphere from these fires … we could end up with a pretty dramatically changed atmosphere”

So huge and sustained were the fires, and so dense the smoke, that the fires began to generate their own thunderstorms, known as pyrocumulonimbus, to create powerful updrafts to carry the aerosols and soot far above the flight paths of the highest jet airliners.

Researchers from France, the UK and Canada used sensitive satellite readings to track the sustained smoke signal from a part-incinerated island: at altitude, it was still dense enough to absorb, scatter and weaken the sunlight falling on the Earth below.

“What was also really amazing was that as the smoke sits in the atmosphere, it starts to absorb sunlight and so it starts to heat up,” Professor Bourassa said.

“And then, because it’s getting hotter, it starts to rise in a swirling vortex bubble, and it just rose higher and higher through the atmosphere.” − Climate News Network

Blazing Australian forests made their mark high in the stratosphere and cast a cloud that lingered for months.

LONDON, 4 November, 2020 − Australian forests, devoured by devastating wildfires in the last southern hemisphere summer, set a new high − a huge smoke cloud that soared more than 20 miles into the upper atmosphere and stayed there for months.

An international team of scientists reports in the Nature journal Communications Earth and Environment that they tracked the cloud to an altitude of 35 kilometres (21 miles).

They measured it as 1,000 kms (625 miles) across. They followed it around the planet for 66,000 kms (41,010 miles). And they confirm that it remained intact for three months.

This high-flying pollution wasn’t the first such instance: just three times the size of any observed predecessor. Until now the record was held by plumes soaring from forest fires in western Canada in 2017.

Growing intensity

“When I saw the satellite measurement of the smoke plume at 35 kms, it was jaw-dropping. I never would have expected that”, said Adam Bourassa of the University of Saskatchewan in Canada, one of the researchers.

“We’re seeing records broken in terms of the impact on the atmosphere from these fires. Knowing that they’re likely to strike more frequently and with more intensity due to climate change, we could end up with a pretty dramatically changed atmosphere.”

A blaze that can make a new cloud 35 kms above its surface is an indicator both of the potential devastation of climate change driven by profligate human use of fossil fuels and of the intricate workings of the biosphere and atmosphere.

After months of desperate drought in 2019, eastern Australia effectively caught fire. Around 110,000 sq kms of bush, forest and grassland went up in smoke: with them went thousands of homes and millions of wild and domestic animals. Altogether 33 people died.

“We’re seeing records broken in terms of the impact on the atmosphere from these fires … we could end up with a pretty dramatically changed atmosphere”

So huge and sustained were the fires, and so dense the smoke, that the fires began to generate their own thunderstorms, known as pyrocumulonimbus, to create powerful updrafts to carry the aerosols and soot far above the flight paths of the highest jet airliners.

Researchers from France, the UK and Canada used sensitive satellite readings to track the sustained smoke signal from a part-incinerated island: at altitude, it was still dense enough to absorb, scatter and weaken the sunlight falling on the Earth below.

“What was also really amazing was that as the smoke sits in the atmosphere, it starts to absorb sunlight and so it starts to heat up,” Professor Bourassa said.

“And then, because it’s getting hotter, it starts to rise in a swirling vortex bubble, and it just rose higher and higher through the atmosphere.” − Climate News Network

Wildfire risk can be reduced with agroforestry

As Australia struggles to recover from months of wildfires, farmers and foresters say agroforestry could help to protect the country.

LONDON, 28 January, 2020 – Researchers in Europe have found that simply adopting a way of managing land to support animals, crops and trees – a system known as agroforestry – can help significantly to cut the risk of wildfires breaking out in areas around the Mediterranean.

As uncontrolled wildfires threaten natural vegetation, biodiversity, communities and economies – and lives – and release large amounts of carbon dioxide, contributing to global temperature rise, the pressure to find ways of controlling them is urgent.

Studying ten years’ worth of data, the researchers analysed the relationship between the incidence of fire and several different uses of land (for agroforestry, forests, shrublands and grasslands). Agroforestry, occupying 12% of the land area, was linked to just 6% of the fires, while shrubland, which occupied 16%, suffered from 41% of the fires (these figures are based on two European Union documents – LUCAS, its Land use and land cover survey, and the European Forest Fire Information System, EFFIS, 2008-17.

Paul Burgess, reader in crop ecology and management at Cranfield University, UK, said: “Areas of shrubland were at particular risk of wildfire – where the land is not proactively managed or used, there is a build-up of dry vegetation and shrubs creating fuel.

Work boost

“Agroforestry is shown to reduce wildfire risk by encouraging rural employment and removing part of the dry ground-level vegetation through livestock grazing. Taking into account the effect of climate change in this region, it is a land management option that can successfully reduce fires, protect the environment and improve human well-being.”

Combining livestock and trees on agroforestry land can create habitats rich in a variety of species that provide an annual income for farmers through livestock products. For clearing vegetation, agroforestry uses less machinery and fossil fuel.

Dr Burgess, who is secretary of the Farm Woodland Forum, told the Climate News Network that agroforestry could help countries like Australia and Portugal to cut the extreme fire risk they have been facing.

He said: “Compared with unmanaged shrubland areas, agroforestry can provide three benefits. Firstly, it encourages local employment and management on the ground which can allow for more rapid initial responses. Then, in most agroforestry systems, the understorey, the vegetation between the forest canopy and the floor, is managed, and this reduces the store of fuel. Third, in many agroforestry systems there are breaks between the trees, which can also help to limit fire spread.”

“Agroforestry is a land management option that can successfully reduce fires, protect the environment and improve human well-being”

The proportion of burnt land in the area studied by the team over 10 years ranged from 0.1% of the area of France to 1-2% of the area of Greece, Cyprus, Italy and Spain, and to 14% of the area of Portugal. The researchers report their study in the journal Agroforestry Systems.

Land abandonment is an important element in the risk of wildfires. In many parts of the Mediterranean, an ageing population and the end of traditional farming and forestry activity have led to extensive unmanaged lands.

This results in an increase in decayed biomass, plant material which readily serves as fuel in shrublands that can be easily ignited by natural events such as thunderstorms, or by human activity.

Other suggestions for reducing wildfires include using sunlight to replace fossil fuel-derived kerosene with a synthetic version, and cutting fossil fuel reliance through wide use of new generation batteries. – Climate News Network

As Australia struggles to recover from months of wildfires, farmers and foresters say agroforestry could help to protect the country.

LONDON, 28 January, 2020 – Researchers in Europe have found that simply adopting a way of managing land to support animals, crops and trees – a system known as agroforestry – can help significantly to cut the risk of wildfires breaking out in areas around the Mediterranean.

As uncontrolled wildfires threaten natural vegetation, biodiversity, communities and economies – and lives – and release large amounts of carbon dioxide, contributing to global temperature rise, the pressure to find ways of controlling them is urgent.

Studying ten years’ worth of data, the researchers analysed the relationship between the incidence of fire and several different uses of land (for agroforestry, forests, shrublands and grasslands). Agroforestry, occupying 12% of the land area, was linked to just 6% of the fires, while shrubland, which occupied 16%, suffered from 41% of the fires (these figures are based on two European Union documents – LUCAS, its Land use and land cover survey, and the European Forest Fire Information System, EFFIS, 2008-17.

Paul Burgess, reader in crop ecology and management at Cranfield University, UK, said: “Areas of shrubland were at particular risk of wildfire – where the land is not proactively managed or used, there is a build-up of dry vegetation and shrubs creating fuel.

Work boost

“Agroforestry is shown to reduce wildfire risk by encouraging rural employment and removing part of the dry ground-level vegetation through livestock grazing. Taking into account the effect of climate change in this region, it is a land management option that can successfully reduce fires, protect the environment and improve human well-being.”

Combining livestock and trees on agroforestry land can create habitats rich in a variety of species that provide an annual income for farmers through livestock products. For clearing vegetation, agroforestry uses less machinery and fossil fuel.

Dr Burgess, who is secretary of the Farm Woodland Forum, told the Climate News Network that agroforestry could help countries like Australia and Portugal to cut the extreme fire risk they have been facing.

He said: “Compared with unmanaged shrubland areas, agroforestry can provide three benefits. Firstly, it encourages local employment and management on the ground which can allow for more rapid initial responses. Then, in most agroforestry systems, the understorey, the vegetation between the forest canopy and the floor, is managed, and this reduces the store of fuel. Third, in many agroforestry systems there are breaks between the trees, which can also help to limit fire spread.”

“Agroforestry is a land management option that can successfully reduce fires, protect the environment and improve human well-being”

The proportion of burnt land in the area studied by the team over 10 years ranged from 0.1% of the area of France to 1-2% of the area of Greece, Cyprus, Italy and Spain, and to 14% of the area of Portugal. The researchers report their study in the journal Agroforestry Systems.

Land abandonment is an important element in the risk of wildfires. In many parts of the Mediterranean, an ageing population and the end of traditional farming and forestry activity have led to extensive unmanaged lands.

This results in an increase in decayed biomass, plant material which readily serves as fuel in shrublands that can be easily ignited by natural events such as thunderstorms, or by human activity.

Other suggestions for reducing wildfires include using sunlight to replace fossil fuel-derived kerosene with a synthetic version, and cutting fossil fuel reliance through wide use of new generation batteries. – Climate News Network

Thinning clouds increase California’s wildfires

Southern California’s wildfires are likely to increase as a protective layer of cloud is driven away by the warmer climate and urban growth.

LONDON, 4 June, 2018 – Southern California’s wildfires are posing a growing risk, as the Sunshine State threatens to become too sunny for its own good. In many southern coastal areas, rising summer temperatures caused by spreading urbanisation and the warming climate are driving off formerly common low-lying morning clouds and increasing the prospect of worse wildfires, US scientists say.

Park Williams, a bioclimatologist at Columbia University’s Lamont-Doherty Earth Observatory, is lead author of their study. He says: “Cloud cover is plummeting in southern coastal California. And as clouds decrease, that increases the chance of bigger and more intense fires.” This conclusion reinforces earlier research which found that low-level clouds could help to cause some cooling.

What is happening is a neat example of a process known by climate scientists as a positive feedback, a way in which climate change contrives to feed on itself to worsen the situation still further (negative feedbacks, by contrast, cool things down). Another example is Arctic melting.

“People in these areas are very good at putting out fires, so the area burned hasn’t gone up. But the dice are now loaded…the fires should be getting more intense and harder to contain”

Professor Williams says the decrease is driven mainly by urban sprawl, which increases near-surface temperatures, but that overall warming climate is contributing too. Increasing heat drives away clouds, admitting more sunlight to heat the ground further, leading to dryer vegetation and higher fire risk. The team’s research is published in the journal Geophysical Research Letters.

It follows a 2015 study in which Williams first documented a decrease in cloud cover around Los Angeles and San Diego. Urban road surfaces and buildings absorb more solar energy than open countryside does, and that heat is radiated back out into the air – a major part of the so-called heat-island effect.

At the same time, overall temperatures have been rising in California thanks to global warming driven by prodigal human combustion of fossil fuels, and this has boosted the effect. In the new study, Williams and his colleagues have found a 25 to 50% decrease in low-lying summer clouds since the 1970s in the greater Los Angeles area.

Normally stratus clouds form over coastal southern California during early morning within a thin layer of cool, moist ocean air sandwiched between the land and higher air masses that are too dry for cloud formation.

Burning off

The stratus zone’s altitude varies with weather, but sits at roughly 1,000 to 3,000 feet (305-915 metres). But heat causes clouds to dissipate, and decades of intense urban growth plus global warming have been damaging the stratus layer’s base, causing it to thin and clouds to burn off earlier in the day or disappear altogether.

Cloud bases have risen 150 to 300 feet since the 1970s, says the study. “Clouds that used to burn off by noon or one o’clock are now gone by 10 or 11 AM, if they form at all,” said Williams.

He and his colleagues have shown a strong link between a warming climate and an increase in wildfires in the western US. But in southern California the link is more subtle, and clouds are a rarely studied part of the system.

However, many of California’s airports have been collecting hourly cloud observations since the 1970s, not for research, but rather for navigational safety. Williams and his colleagues used this data to develop a fine-grained picture of changing cloud cover over the region.

Telling comparison

They then compared it to a separate large database kept by the US Wildland Fire Assessment System, whose researchers have for decades regularly measured vegetation moisture in the hills outside Los Angeles. By comparing the two data sets they found that periods of less cloud cover during the summer correlated neatly with lower vegetation moisture, and thus more danger of fire.

But the study has not found that the total area burned in summer has increased because of decreases in cloud shading. There are too many other factors at play, says Professor Williams, including yearly rainfall variations, winds, the places where fires start, and – perhaps most of all – decreases in burnable area as urban districts have grown, together with the increased effectiveness of fire-fighting.

“Even though the danger has increased, people in these areas are very good at putting out fires, so the area burned hasn’t gone up,” he said. “But the dice are now loaded, and in areas where clouds have decreased, the fires should be getting more intense and harder to contain. At some point, we’ll see if people can continue to keep up.”

The California-wide fires in the autumn of 2017 were probably not strongly affected by the reductions in summer cloud cover, he said. They were driven mainly by extreme winds and a late onset of the autumn rainy season. But he expects to see California’s overall fire danger increase, as long as there is adequate vegetation to burn. – Climate News Network

Southern California’s wildfires are likely to increase as a protective layer of cloud is driven away by the warmer climate and urban growth.

LONDON, 4 June, 2018 – Southern California’s wildfires are posing a growing risk, as the Sunshine State threatens to become too sunny for its own good. In many southern coastal areas, rising summer temperatures caused by spreading urbanisation and the warming climate are driving off formerly common low-lying morning clouds and increasing the prospect of worse wildfires, US scientists say.

Park Williams, a bioclimatologist at Columbia University’s Lamont-Doherty Earth Observatory, is lead author of their study. He says: “Cloud cover is plummeting in southern coastal California. And as clouds decrease, that increases the chance of bigger and more intense fires.” This conclusion reinforces earlier research which found that low-level clouds could help to cause some cooling.

What is happening is a neat example of a process known by climate scientists as a positive feedback, a way in which climate change contrives to feed on itself to worsen the situation still further (negative feedbacks, by contrast, cool things down). Another example is Arctic melting.

“People in these areas are very good at putting out fires, so the area burned hasn’t gone up. But the dice are now loaded…the fires should be getting more intense and harder to contain”

Professor Williams says the decrease is driven mainly by urban sprawl, which increases near-surface temperatures, but that overall warming climate is contributing too. Increasing heat drives away clouds, admitting more sunlight to heat the ground further, leading to dryer vegetation and higher fire risk. The team’s research is published in the journal Geophysical Research Letters.

It follows a 2015 study in which Williams first documented a decrease in cloud cover around Los Angeles and San Diego. Urban road surfaces and buildings absorb more solar energy than open countryside does, and that heat is radiated back out into the air – a major part of the so-called heat-island effect.

At the same time, overall temperatures have been rising in California thanks to global warming driven by prodigal human combustion of fossil fuels, and this has boosted the effect. In the new study, Williams and his colleagues have found a 25 to 50% decrease in low-lying summer clouds since the 1970s in the greater Los Angeles area.

Normally stratus clouds form over coastal southern California during early morning within a thin layer of cool, moist ocean air sandwiched between the land and higher air masses that are too dry for cloud formation.

Burning off

The stratus zone’s altitude varies with weather, but sits at roughly 1,000 to 3,000 feet (305-915 metres). But heat causes clouds to dissipate, and decades of intense urban growth plus global warming have been damaging the stratus layer’s base, causing it to thin and clouds to burn off earlier in the day or disappear altogether.

Cloud bases have risen 150 to 300 feet since the 1970s, says the study. “Clouds that used to burn off by noon or one o’clock are now gone by 10 or 11 AM, if they form at all,” said Williams.

He and his colleagues have shown a strong link between a warming climate and an increase in wildfires in the western US. But in southern California the link is more subtle, and clouds are a rarely studied part of the system.

However, many of California’s airports have been collecting hourly cloud observations since the 1970s, not for research, but rather for navigational safety. Williams and his colleagues used this data to develop a fine-grained picture of changing cloud cover over the region.

Telling comparison

They then compared it to a separate large database kept by the US Wildland Fire Assessment System, whose researchers have for decades regularly measured vegetation moisture in the hills outside Los Angeles. By comparing the two data sets they found that periods of less cloud cover during the summer correlated neatly with lower vegetation moisture, and thus more danger of fire.

But the study has not found that the total area burned in summer has increased because of decreases in cloud shading. There are too many other factors at play, says Professor Williams, including yearly rainfall variations, winds, the places where fires start, and – perhaps most of all – decreases in burnable area as urban districts have grown, together with the increased effectiveness of fire-fighting.

“Even though the danger has increased, people in these areas are very good at putting out fires, so the area burned hasn’t gone up,” he said. “But the dice are now loaded, and in areas where clouds have decreased, the fires should be getting more intense and harder to contain. At some point, we’ll see if people can continue to keep up.”

The California-wide fires in the autumn of 2017 were probably not strongly affected by the reductions in summer cloud cover, he said. They were driven mainly by extreme winds and a late onset of the autumn rainy season. But he expects to see California’s overall fire danger increase, as long as there is adequate vegetation to burn. – Climate News Network

Temperature rise will fan forest flames

FOR IMMEDIATE RELEASE The forest fires raging through states in the western US are among the worst on record, but latest research indicates that they will get even worse in future as temperatures rise. LONDON, 2 September − As fire crews battle to control the forest fires that have been devastating areas of the western US, a bleak warning has been issued that such fires in future are likely to break out over longer periods and wider areas each year, and create up to twice as much smoke. Forest wildfires are a regular event in California and other states in the western US, but this year’s conflagrations are being described as some of the worst on record. One fire, which has threatened California’s Yosemite National Park, was at one stage spread over nearly 200,000 acres, or more than 300 square miles. Environmental scientists at Harvard School of Engineering and Applied Sciences (SEAS) fed data into a number of models to come up with predictions about how such fires will behave in future. The data included not only historical records of fires but also seasonal temperatures, relative humidity levels, and amounts of brush and dry fuel on the forest floor over six “ecoregions” in the western states. The models were matched with data from the fourth Intergovernmental Panel on Climate Change (IPCC) report on possible future atmospheric and climatological conditions for the year 2050. Based on this multi-model approach, the Harvard team was then able to calculate the likely extent of fires in mid-century, and to gauge areas that would be burned. “We weren’t altogether certain what we would find when we started this project,” says Loretta J Mickley, the study’s co-author and a senior research fellow in atmospheric chemistry at Harvard SEAS.

Conducive to fires

“In the future, we expect warmer temperatures, which are conducive to fires, but it’s not apparent what the rainfall and relative humidity will do. Warmer air can hold more water vapour, for instance, but what does this mean for fires? “It turns out that, for the western US, the biggest driver for fires in the future is temperature, and that result appears robust across models. When you get a large temperature increase over time, as we are seeing, and little rainfall, fires will increase in size.” Among the study’s forecasts for fires in the western US in 2050 are:

  • Areas burned in the month of August could increase by 65% in the Pacific Northwest, nearly double in the Eastern Rocky mountains, and quadruple in the Rocky Mountains Forest region.
  • Probability of large fires could increase by factors of two or three.
  • The start dates of the “fire season” could be earlier (late April instead of mid-May) and the end date could be later (mid-October instead of early October).

During the last 40 years, air quality has improved considerably over much of the US, mainly due to government efforts on regulating emissions. However, the study predicts that, due to more fires, smoke levels could increase by between 20% and 100% by 2050. “I think what people need to realise is that embedded in those curves showing the tiny temperature increases year after year are more extreme events that can be quite serious,” Mickley  says.  “It doesn’t bode well.” − Climate News Network

FOR IMMEDIATE RELEASE The forest fires raging through states in the western US are among the worst on record, but latest research indicates that they will get even worse in future as temperatures rise. LONDON, 2 September − As fire crews battle to control the forest fires that have been devastating areas of the western US, a bleak warning has been issued that such fires in future are likely to break out over longer periods and wider areas each year, and create up to twice as much smoke. Forest wildfires are a regular event in California and other states in the western US, but this year’s conflagrations are being described as some of the worst on record. One fire, which has threatened California’s Yosemite National Park, was at one stage spread over nearly 200,000 acres, or more than 300 square miles. Environmental scientists at Harvard School of Engineering and Applied Sciences (SEAS) fed data into a number of models to come up with predictions about how such fires will behave in future. The data included not only historical records of fires but also seasonal temperatures, relative humidity levels, and amounts of brush and dry fuel on the forest floor over six “ecoregions” in the western states. The models were matched with data from the fourth Intergovernmental Panel on Climate Change (IPCC) report on possible future atmospheric and climatological conditions for the year 2050. Based on this multi-model approach, the Harvard team was then able to calculate the likely extent of fires in mid-century, and to gauge areas that would be burned. “We weren’t altogether certain what we would find when we started this project,” says Loretta J Mickley, the study’s co-author and a senior research fellow in atmospheric chemistry at Harvard SEAS.

Conducive to fires

“In the future, we expect warmer temperatures, which are conducive to fires, but it’s not apparent what the rainfall and relative humidity will do. Warmer air can hold more water vapour, for instance, but what does this mean for fires? “It turns out that, for the western US, the biggest driver for fires in the future is temperature, and that result appears robust across models. When you get a large temperature increase over time, as we are seeing, and little rainfall, fires will increase in size.” Among the study’s forecasts for fires in the western US in 2050 are:

  • Areas burned in the month of August could increase by 65% in the Pacific Northwest, nearly double in the Eastern Rocky mountains, and quadruple in the Rocky Mountains Forest region.
  • Probability of large fires could increase by factors of two or three.
  • The start dates of the “fire season” could be earlier (late April instead of mid-May) and the end date could be later (mid-October instead of early October).

During the last 40 years, air quality has improved considerably over much of the US, mainly due to government efforts on regulating emissions. However, the study predicts that, due to more fires, smoke levels could increase by between 20% and 100% by 2050. “I think what people need to realise is that embedded in those curves showing the tiny temperature increases year after year are more extreme events that can be quite serious,” Mickley  says.  “It doesn’t bode well.” − Climate News Network

Alaska's forest fires burn more fiercely

FOR IMMEDIATE RELEASE
Some recent fires in the forests of Alaska have been the worst for 10,000 years, researchers say – and they could happen elsewhere in this warming world.

LONDON, 26 July – There have always been fires in the cold forests of Alaska. Periods of burning are part of the ecological regime, and fires return to black spruce stands of the Yukon Flats at intervals of tens to hundreds of years.

But recent evidence suggests that fire is about to come back with a vengeance – or, in the language of science, “a transition to a unique regime of unprecedented fire activity”.

Ryan Kelly and Feng Sheng Hu, two biologists at the University of Illinois, Urbana, have examined charcoal records from 14 lakes in Yukon Flats to reconstruct the history of burning for the last 10,000 years.

They and colleagues report in the Proceedings of the National Academy of Sciences that during the Medieval Climate Anomaly – the warm period that brought monastery vineyards to Britain a thousand years ago – the dry conditions favoured what they call “peak biomass burning”.

But this apparent limit has, they report, been surpassed during recent decades, characterised by “exceptionally high fire frequency and biomass burning.”

Their warning came during a week in which, on just one day, the US space agency Nasa published satellite images of burning scrub and forest in the states of California and Idaho, in the Irkutsk region of south-eastern Siberia, and of illegal slash-and-burn fires to clear land in Indonesia.

This last led to unprecedented levels of air pollution in Malaysia and Singapore: schools were closed and aircraft grounded, and the Government of Malaysia issued gas masks.

Potential for ‘dramatic impacts’

The fires in the northern forests matter, because the boreal forests cover about a tenth of the planet’s land surface, and they store about 30% of the planet’s terrestrial carbon.

So they are vulnerable to global warming, climate change and wildfire: wetlands, too, are likely to dry up, and permafrost continues to melt, all of which makes the forests more vulnerable. When they burn, the stands of timber release huge amounts of carbon into the atmosphere.

The slow return to normal has its own knock-on effects, say the authors: it has an impact on biogeochemical cycles, on the energy balance and the hydrology of the region, all of which can in turn feed back into climate change.

So to understand the possible global consequences for the northern forests, the authors reasoned, it would pay dividends to make a case study of one sustained natural experiment in one easily accessible landscape.

The researchers found that, after bouts of burning in centuries past, the area was colonised by more fire-resistant species, and the same has begun to happen after the most recent fires. They report that Yukon Flats is now a fragmented mosaic of “lower flammability vegetation” which ought to keep the place safe for a while.

But the fires of recent years have been the worst for 10,000 years and, they warn, things are likely to get worse: what happened to the conifers of Alaska could happen in other places as the world warms and the sub-Arctic begins to dry, with a change to deciduous trees. “Such dynamics”, they say, “have potentially dramatic ecological impacts.” – Climate News Network

FOR IMMEDIATE RELEASE
Some recent fires in the forests of Alaska have been the worst for 10,000 years, researchers say – and they could happen elsewhere in this warming world.

LONDON, 26 July – There have always been fires in the cold forests of Alaska. Periods of burning are part of the ecological regime, and fires return to black spruce stands of the Yukon Flats at intervals of tens to hundreds of years.

But recent evidence suggests that fire is about to come back with a vengeance – or, in the language of science, “a transition to a unique regime of unprecedented fire activity”.

Ryan Kelly and Feng Sheng Hu, two biologists at the University of Illinois, Urbana, have examined charcoal records from 14 lakes in Yukon Flats to reconstruct the history of burning for the last 10,000 years.

They and colleagues report in the Proceedings of the National Academy of Sciences that during the Medieval Climate Anomaly – the warm period that brought monastery vineyards to Britain a thousand years ago – the dry conditions favoured what they call “peak biomass burning”.

But this apparent limit has, they report, been surpassed during recent decades, characterised by “exceptionally high fire frequency and biomass burning.”

Their warning came during a week in which, on just one day, the US space agency Nasa published satellite images of burning scrub and forest in the states of California and Idaho, in the Irkutsk region of south-eastern Siberia, and of illegal slash-and-burn fires to clear land in Indonesia.

This last led to unprecedented levels of air pollution in Malaysia and Singapore: schools were closed and aircraft grounded, and the Government of Malaysia issued gas masks.

Potential for ‘dramatic impacts’

The fires in the northern forests matter, because the boreal forests cover about a tenth of the planet’s land surface, and they store about 30% of the planet’s terrestrial carbon.

So they are vulnerable to global warming, climate change and wildfire: wetlands, too, are likely to dry up, and permafrost continues to melt, all of which makes the forests more vulnerable. When they burn, the stands of timber release huge amounts of carbon into the atmosphere.

The slow return to normal has its own knock-on effects, say the authors: it has an impact on biogeochemical cycles, on the energy balance and the hydrology of the region, all of which can in turn feed back into climate change.

So to understand the possible global consequences for the northern forests, the authors reasoned, it would pay dividends to make a case study of one sustained natural experiment in one easily accessible landscape.

The researchers found that, after bouts of burning in centuries past, the area was colonised by more fire-resistant species, and the same has begun to happen after the most recent fires. They report that Yukon Flats is now a fragmented mosaic of “lower flammability vegetation” which ought to keep the place safe for a while.

But the fires of recent years have been the worst for 10,000 years and, they warn, things are likely to get worse: what happened to the conifers of Alaska could happen in other places as the world warms and the sub-Arctic begins to dry, with a change to deciduous trees. “Such dynamics”, they say, “have potentially dramatic ecological impacts.” – Climate News Network