Shrinking harvests likely as heat increases

A warmer world could mean shrinking harvests and a more meagre diet for millions of people, according to two new studies.

LONDON, 19 June, 2018 – A hotter world could also be a hungrier one, with shrinking harvests and poorer quality plants. As planetary temperatures rise in response to ever more profligate combustion of fossil fuels, climate change could lower the yield of  vegetable and legume crops – and at the same time reduce their nutritional content.

And the same high end-of-the-century temperatures could raise the risk of massive, near-global losses for the world’s most widely grown cereal, maize.

This double blow comes close upon the evidence – from field trials over many years – that another global staple, rice, is likely to become less rich in protein and vitamins as temperatures increase.

British researchers report in the Proceedings of the National Academy of Sciences that they studied 174 research papers based on 1,540 experiments in 40 countries between 1975 and 2016, on the probable effect of changes in water supplies, ozone, atmospheric carbon dioxide and ambient temperatures, on vegetables and legumes.

They found that on the basis of changes predicted for later this century, average yields of vegetables could fall by 35%, and legumes by 9%. There has been evidence that more atmospheric carbon dioxide could fertilise more plant growth, but other accompanying changes – greater extremes of heat, drought, flood and so on – could cancel out any such gains.

“As the planet warms, it becomes more likely for different countries to simultaneously experience major crop losses”

Pauline Scheelbeck, of the London School of Hygiene and Tropical Medicine, who led the study, called the finding “a real threat to global agricultural production, with likely impacts on food security and population health.”

Scientists have been warning for at least five years of the potential impact of climate change on agriculture and food supply: other studies have shown that fruit and vegetable supplies could be at risk.

There has also been evidence that heat extremes could damage wheat yields while endangering food supplies across the whole of Africa, and at the very least test the capacity of global markets to cope with sudden harvest failures across whole regions.

US researchers report – once again, in the Proceedings of the National Academy of Sciences – that they took a fresh look at the response of markets to what they call “volatility” in the global crop of just one cereal: maize, or corn.

Heavy dependence

This is grown widely: it is a staple for humans and fodder for livestock; it provides oil for cooking and has even been turned into fuel for motor cars. It is traded worldwide, but four countries – the US, Brazil, Argentina and Ukraine – account for more than 85% of all exports. The chance that all four exporters would have bad harvests in the same year right now is almost zero.

But under a warming of 2°C – a level which 195 nations agreed in Paris in 2015 to keep well below – this risk would rise to 7%. If global temperatures rise by 4°C, which is what will happen if humans go on burning ever more fossil fuels, the chance that all four maize exporters would have harvest failures at the same time rises to 86%. And, if that happened, corn prices would rise dramatically.

“When people think about climate change and food, they initially think about drought, but it’s really extreme heat that’s very detrimental for crops,” said Michelle Tigchelaar of the University of Washington, who led the research.

“We find that as the planet warms, it becomes more likely for different countries to simultaneously experience major crop losses, which has big implications for food prices and food security.” – Climate News Network

Light from plant growth shows carbon budget

Invisible flickering detected by satellite could throw new light from plant growth on the mysteries of the planet’s carbon budget.

LONDON, 18 June, 2018 – For the first time, light from plant growth may let humans see – almost at a glance – how greedily the planet’s vegetation sucks carbon dioxide from the atmosphere.

US-based researchers have confirmed that they can detect the same glow – invisible to the human eye – from trees, grasslands, crops, mangroves, marches and desert plants as the green things put chlorophyll to work and photosynthesise leaves, flowers, fruits and roots from atmospheric carbon.

The pay-off is simple: an easier and potentially more accurate way of calculating the global carbon budget and assessing the climate cost of human exploitation of fossil fuels.

But the same information will help biologists and geoscientists advance what is sometimes called earth system science: how carbon-based lifeforms make their living from sunlight, water and carbon dioxide in a continuous trafficking that has fuelled 3bn years of evolution.

And at the heart of the study is a new realisation that images from an orbiting satellite deliver better information in a reliable fashion.

“This is a big step towards being able to solely rely on satellite measurements”

Researchers have exploited data from orbiting earth observation satellites to measure the diminishing thickness of the polar ice caps and their dwindling extent, as human-induced global warming warms the oceans and raises the sea levels.

They have helped measure the response of different kinds of forest to global warming, and changes to ocean chemistry as ever greater levels of greenhouse gas enter the atmosphere, as humans burn ever more fossil fuels.

But one satellite, launched specifically to answer questions about the traffic between living things and the carbon dioxide in the atmosphere, has delivered information with even greater precision that anyone expected.

Researchers from the University of New Hampshire report in the journal Global Change Biology that years of observation of solar-induced fluorescence – a glow from plants that no human could expect to see, but an instrument can detect – have confirmed that there is a direct relationship between gross primary productivity and the amount of fluorescence registered by the eye in the sky.

No exceptions

It means that what is true for the canopy of tropical forests in the Congo would also be true for a landscape of maize in the American mid-West, or the grasses and wildflowers of the savannah, the dusty maquis of the Mediterranean, or the swamps of the Louisiana bayous.

Up till now, researchers have tried to make accurate and reliable estimates on the ground, playing with air temperature, sunlight, rainfall and other factors to arrive at their conclusions about what they like to call carbon “sinks.” The message from OCO-2, the NASA orbiting carbon observatory, is that the gleam from the foliage below provides an answer more swiftly, and perhaps more surely.

“The importance of these results is that rather than look at several different types of data and computer-based models from information collected on the ground to monitor plant photosynthesis across the globe, using the satellite observations will provide a near real-time option that is simple, reliable and fast,” said Jingfeng Xiao, of the University of New Hampshire, the chief investigator.

“This is a big step towards being able to solely rely on satellite measurements.” – Climate News Network

Slowing tropical cyclones bring more mayhem

Tropical cyclones are slowing down. Hurricanes have lost their hurry. Paradoxically, this is bad news: they have more time to work their mischief.

LONDON, 15 June, 2018 – Tropical cyclones are moving more slowly. As temperatures rise, the pace at which a hurricane storms across a landscape has slowed perceptibly in the last 70 years. But the slowdown means each hurricane has more time to do more damage and deliver more flooding.

“Tropical cyclones over land have slowed down 20% in the Atlantic, 30% in the northwestern Pacific and 19% in the Australian region,” said James Kossin, of the US National Oceanic and Atmospheric Administration’s national centres for environmental information.

“These trends are almost certainly increasing local rainfall totals and freshwater flooding, which is associated with a very high mortality risk.”

He reports in the journal Nature that thanks to atmospheric warming as a consequence of the profligate combustion of fossil fuels in the last century, the summer tropical circulation has slowed and, along with it, hurricane and typhoon speeds. Overall, since 1940, cyclone movements have slowed by 10%; over some land areas, they have slowed much more.

But as the temperature goes up, the capacity of the atmosphere to hold moisture increases – by at least 7% with each degree Centigrade. That means a tropical cyclone – a whirling system of terrifying winds bearing huge quantities of water – has both more water, and more time to drop it over land.

Harvey’s warning

And Dr Kossin cites the example of Hurricane Harvey which in 2017 dumped more than 1.25 metres of water on Houston, Texas and the surrounding countryside in just five days. Devastating floods displaced 30,000 people, and 89 died. Economic losses were assessed at more than $126bn.

This shift in what researchers call the translation speed is new – and is only the latest study in a procession of alarming findings about the response of the winds in a warming world.

Researchers have already established that hurricanes are gaining in ferocity – that is, becoming more intense – at a faster rate than they did decades ago. They have warned that windstorms’ capacity to damage the world’s economy is on the increase directly because of global warming and consequent climate change, and they have identified a trend in hurricane geography: the storms are moving further north, in the northern hemisphere.

The combination of rising sea levels and fiercer storms could create, some argue, a new class of climate refugee in the US. And they have bad news for Texas: more storms like Harvey could be on the way.

“These trends are almost certainly increasing local rainfall totals and freshwater flooding, which is associated with a very high mortality risk”

In the course of the last century, global average temperatures have, as a consequence of the notorious greenhouse effect, gone up by around 1°C. Around 195 nations agreed in Paris in 2015 to attempt to contain global warming to 1.5°C in total by 2100, but gloomy forecasts suggest that unless action becomes urgent, temperatures will rise much higher.

And that means that hurricanes will go on slowing, to deliver ever more damage as they linger over coastal cities and farmlands.

“The observed 10% slowdown occurred in a period when the planet warmed by 0.5°C, but this does not provide a true measure of climate sensitivity, and more study is needed to determine how much more slowing will occur with continued warming,” Dr Kossin said.

“Still, it’s entirely plausible that local rainfall increases could actually be dominated by this slowdown rather than that the expected rain-rate increases due to global warming”. – Climate News Network

Cost of fossil fuel investment is too high

Fossil fuel investment is not just bad for the global climate. It could also be dangerous for investors, and for national economies.

LONDON, 12 June, 2018 – European and Chinese scientists have identified a simple new way to become poor: fossil fuel investment. Not only could it leave you without a penny to your name. It could perhaps precipitate a global financial crash within one generation.

Coal, oil and natural gas are already huge investments. The International Energy Agency foresees price rises until 2040, and investor confidence is high. But researchers from the Netherlands, the UK and Macao don’t see it that way.
They warn in the journal Nature Climate Change that, whatever the markets think, and whatever governments do, change is on the way.

Other forces are now driving global power and transportation in directions that suggest a dramatic decline in demand for fossil reserves. These will become what the money markets call “stranded assets”, and their value will slump some time before 2035.

And this bursting of what researchers call “the carbon bubble” – a reference to a three-centuries old financial disaster known to historians as the South Sea Bubble – could wipe between one and four trillion US dollars off the global economy. The financial crash of 2008  was triggered by a loss of a mere $0.25 trillion.

“Our analysis suggests that, contrary to investor expectations, the stranding of fossil fuel assets may happen even without new climate policies”

The scientists base their conclusion on a computer simulation known by the migraine-inducing acronym E3ME-FTT-GENIE, which is short for Energy-Environment-Economy Macroeconomic-Future Technology Transformations Grid Enabled Integrated Earth. They say it is the only such model that looks at the big picture: the macroeconomy, energy, the environment and global energy and transport systems according to both sector and geography.

Their argument is that the world is heading towards greater fuel efficiencies, renewable energy and low carbon technologies, whatever governments and the money markets may think.

In 2015, in Paris, 195 nations vowed to contain global warming – driven by greenhouse gases emitted from fossil fuel combustion – to “well below” 2°C above the historic levels. Economists and climate scientists have repeatedly warned that fossil fuels would be a bad bet. There has been evidence since the Paris Agreement that national and international action so far taken is not enough: the world could be heading for at least a 3°C rise this century.

The implication of the latest study is that, unless the world faces this reality, and switches to low-carbon investments, the global economy could suddenly collapse.
“Our analysis suggests that, contrary to investor expectations, the stranding of fossil fuel assets may happen even without new climate policies. This suggests a carbon bubble is forming and is likely to burst,” said Jorge Viñuales, of the University of Cambridge, and one of the authors.

“Individual nations cannot avoid the situation by ignoring the Paris Agreement or burying their heads in coal and tar sands. For too long, global climate policy has been seen as a prisoner’s dilemma game, where some nations can do nothing and get a free ride on the efforts of others. Our results show this is no longer the case.”

$4tn time-bomb

There is a catch: suppose nations become aware of the danger. A sudden push to fulfil the 2°C promise, combined with declines in fossil fuel demand but continued high output of fossil fuels, could trigger a collapse that would wipe $4 trillion off the global balance sheets.

Canada, Russia and the US would see their fossil fuel industries collapse. Fuel-importing nations such Japan, China and most EU countries might gain, especially if they had invested in low-carbon technologies to create jobs and boost gross domestic product.

“If we are to defuse this time-bomb in the global economy, we need to move promptly but cautiously. The carbon bubble must be deflated before it becomes too big, but progress must also be carefully managed,” said Hector Pollitt, of the University of Cambridge, and another of the authors.

“If countries keep investing in equipment to search for, extract, process and transport fossil fuels, even though their demand declines, they will end up losing money on these investments on top of their losses due to limited exports,” said Jean-François Mercure of Radboud University at Nijmegen in the Netherlands, and of Cambridge, who led the study. “Divestment from fossil fuels is both a prudent and necessary thing to do.” – Climate News Network

Extinction may silence advanced civilisations

ET hasn’t been in touch. Enduring silence may be the real message from distant and ancient galaxies, if advanced civilisations destroy the conditions for their own survival.

LONDON, 11 June, 2018 – US scientists have calculated the conditions for the survival of a civilisation – all advanced civilisations across the vast universe. Their calculations may explain why, so far, extraterrestrial beings have failed to get in touch.

They may also help explain why climate change driven by global warming could be both inevitable and potentially calamitous.

Entirely theoretical research of this kind is the basis of astrobiology: the attempt to understand why life exists in a seemingly hostile universe, and why, if it exists on Earth, it is not visible everywhere. For practical data, astrobiologists have only one instance of life, and one of intelligent advanced civilisation to work with: planet Earth.

Adam Frank, of the University of Rochester, New York, and colleagues report in the journal Astrobiology that they considered the evidence of a vanished civilisation on Earth – the mysterious culture that flourished on Easter Island in the Pacific and then vanished by about 1500AD.

Better insight

“If we’re not the universe’s first civilisation, that means there are likely to be rules for how the fate of a young civilisation like our own progresses,” said Professor Frank.

“The point is to recognise that driving climate change may be something generic. The laws of physics demand that any young population, building an energy-intensive civilisation like ours, is going to have feedback on its planet. Seeing climate change in this cosmic context may give us better insight into what’s happening to us now and how to deal with it.”

The principle is that any civilisation must change its planet, and the most obvious way would be by exploiting resources in ways that might affect average planetary temperatures.

Under such circumstances the population could reach a peak – and then die off, leaving a few survivors. Or it could foresee the problems and go for sustainability rather than ever more growth. Or population and temperature could reach a peak, at which point the civilisation would collapse. Or – disconcertingly – the threatened civilisation could identify the looming disaster but fail to act in time.

Fatal delay

“The last scenario is the most frightening,” said Professor Frank. “Even if you did the right thing, if you waited too long, you could still have your population collapse.”

Geoscientists have already identified a new phase of Earth history: the planet has now entered an epoch informally called the Anthropocene. They have already established that, in principle, the build-up of greenhouse gases in the atmosphere as a consequence of the exploitation of fossil fuels could raise temperatures to a point that would make civilisation, and perhaps even life on Earth, unsustainable.

Professor Frank himself has explored these questions in earlier studies. In 2014, he and colleagues asked themselves how long an alien civilisation that had discovered fossil fuels, and therefore changed the conditions in which it evolved, could sustain itself.

Earlier this year he returned to the theme and asked how modern humans could ever know if some intelligent non-human civilisation had once ruled the planet and then obliterated itself. Easter Island’s vanished overlords, the people who built the vast stone statues that now stand in enigmatic silence over an impoverished landscape, become in such a case an object lesson.

“If we’re not the universe’s first civilisation, that means there are likely to be rules for how the fate of a young civilisation like our own progresses”

Archaeological evidence suggests that a culture emerged perhaps 1600 years ago, population grew to a peak, resources were over-exploited, population collapsed and, with it, all memory of what once had been. If an isolated island had a maximum carrying capacity, then so ultimately would an isolated planet. Professor Frank sees global climate change as a planet’s response to civilisation.

“If you go through really strong climate change, then your carrying capacity may drop, because, for example, large-scale agriculture might be strongly disrupted. Imagine if climate change caused rain to stop falling in the Midwest. We wouldn’t be able to grow food, and our population would diminish,” he said.

“If you change the Earth’s climate enough, you might not be able to change it back. Even if you backed off and started to use solar or other less impactful resources, it could be too late, because the planet has already been changing.

“These models show we can’t just think about a population evolving on its own. We have to think about our planets and civilisations co-evolving.” – Climate News Network

Global green vision is do-able, with an effort

The global green vision can become reality, with warming held to 1.5°C. Energy efficiency, radical changes to diet, and renewable energy can together save the planet.

LONDON, 7 June, 2018 – The world could be about to change, turning the ambitious global green vision into fact. Even as the poorest nations go on developing, the population climbs and demand for food increases, energy-efficient technologies could make the world a better place, an international team of scientists says.

Innovations already in use could expand to reduce energy demand in buildings and transport, and new smart technologies – together with a shift in diets worldwide – could reduce global energy demand by 40% by 2050.

That would mean a switch from fossil fuels and towards the goal of global warming of no more than 1.5°C above historic averages, without the use of as-yet-unproven technologies to draw down carbon dioxide from the atmosphere and store it in deep caverns.

And – entirely separately – two independent studies in two other journals support hope for the globe: British and Swiss researchers have taken a detailed look at food and farming choices that could – if nations selected the best and adopted them wholeheartedly – reduce the total of global agricultural land by more than 70%, to release more space for natural ecosystems that support all the teeming species on the planet.

And European scientists have taken a fresh look at an old question – can renewable energies such as wind and solar power actually supply 100% of the world’s energy needs? They have delivered a firm answer: yes, they could.

“Now let’s get back to the business of modelling low-cost scenarios to eliminate fossil fuels from our energy system”

The first study, in the journal Nature Energy, outlines a global scenario in which energy demand becomes low: it does so because a number of shifts in thinking have begun to drive change.

One of these is a worldwide push for higher living standards, cleaner local environments and widely accessible services. Another push for change is the trend towards urbanisation: more than half of all people now live in cities, and the proportion will rise.

A third is the increasing sophistication of technologies, as instanced by the smartphone – in which communications, entertainment, navigation, news and other services are all managed in one low-energy handheld device. Another is the change in the way people – traders, consumers, producers, designers, citizens and so on – now use energy.

These together could within the next three decades direct the world to the 1.5°C maximum target agreed in Paris in 2015 – with a global final energy demand around 40% lower than today, despite a dramatic increase in global population and in global income.

Individual changes

“Changes in the ways that we as the final users of energy go about our daily lives have knock-on effects on the ways that goods are manufactured and transported around, offices and malls are built, and food is grown,” said Arnulf Grübler of the International Institute for Applied Systems Analysis in Austria, who led the study.

Such changes would require unprecedented action by policymakers, as well as sweeping changes in individual appetites: even so, a switch to much less use of red meat could, the researchers argue, return agricultural land to the wild forests over an area the size of Italy and Bangladesh together.

“The global community from world leaders and multinational corporations down to individual consumers and citizens need to act in concert to avoid dangerous climate change while improving human wellbeing. Our scenario offers a roadmap as to how this can be achieved,” Professor Grübler said.

And while the IIASA team were considering global energy demand, a team from Oxford were testing the rewards of potential changes in human appetite. They report in the journal Science that they analysed 570 studies of around 38,000 farms and 1,600 food processors, packers and retailers in 123 countries to take the measure of the environmental impact of 40 different food products.

Plant-based diets

They found huge differences: to deliver 100 grams of beef protein, some producers released more than 105 kilograms of greenhouse gases and required 370 square metres of land; other beef producers could do the same with 50 times less impact on the environment.

But the “efficient” beef producers still used 36 times more land and produced six times more emissions than it took to put 100 grams of peas on the dinner table.

“Two things that look the same in the shops can have very different impacts on the planet. We don’t currently know this when we make choices about what to eat. Further, this variability isn’t recognised in strategies and policy aimed at reducing the impacts of farmers,” said Joseph Poore, a zoologist at the University of Oxford, who led the Science study.

This is a case that has been made before. But Poore and his Swiss colleague suggest new and more ambitious rewards: they have calculated that plant-based diets could cut greenhouse gas emissions by up to 73%, and reduce up to 3.1 billion hectares of global agricultural land, a cut of 76%. “This could take pressure off the world’s tropical forests and release land back to nature,” said Joseph Poore.

Renewable energy delivers

But even as humankind reduces greenhouse gas emissions by dietary change, German, Finnish, Danish and South African scientists have returned to an argument that has continued at national and international levels for years.

They write in the journal Renewable and Sustainable Energy Reviews  – which publishes both sides of this debate – that energy systems based on renewables “are not only feasible, but already economically viable and decreasing in cost every year.”

One of the researchers, Brian Vad Mathiesen of Aalborg University in Denmark, said: “There are some persistent myths that 100% renewable systems are not possible. Our contribution deals with these myths one by one, using all the latest research.

“Now let’s get back to the business of modelling low-cost scenarios to eliminate fossil fuels from our energy system, so we can tackle the climate and health challenges they pose.” – Climate News Network

World’s great cities hold key to fossil fuel cuts

The great cities, hotspots of global wealth creation, are great emitters of greenhouse gases. Civic leaders could be among those best placed to save the planet.

LONDON, 6 June, 2018 – Governments anxious to reduce the national use of fossil fuels and limit climate change now know where to start: in the great cities. New research has confirmed what with benefit of hindsight should have been obvious – that the 54% of humanity that lives in the cities now accounts for more than 70% of global energy use.

And a new study of the so-called “carbon footprint” of 13,000 of the world’s urban areas has identified the most effective places to start. “The top 100 highest footprint cities worldwide drive roughly 20% of the global carbon footprint,” said Daniel Moran, of the Norwegian University of Science and Technology.

“This means concerted action by a small number of local mayors and governments can significantly reduce national carbon footprints.”

Matching information

Dr Moran and colleagues from Japan, the US and Sweden report in the journal Environmental Research Letters that they defined cities as densely populated, contiguously built-up urban areas, often straddling administrative boundaries. From space, Manchester and Salford in the UK would look like one city; Manhattan and Brooklyn, in the US, or Tokyo and Yokohama in Japan, would fade into each other.

The researchers then matched all the information they could find about existing carbon footprints – estimates of energy consumption – with national statistics on spending patterns, regional purchasing power data and a population map.

Cities – historic concentrations of people, business, industry, government, legislation, learning and inventiveness – are also concentrations of economic growth: 600 urban centres are thought to account for about 60% of global gross domestic product.

Cities may drive climate change, but they are also concentrations of people who will be most at risk, not just because cities are hotter than the surrounding countryside, but because, as the world warms, more people in more cities become increasingly vulnerable to extremes of heat and flood.

“Concerted action by a small number of local mayors and governments can significantly reduce national carbon footprints”

The message of the study is simple: when it comes to reducing fossil fuel use, carbon footprint and emissions of greenhouse gas, mayors, governors, councils and city bosses have as much opportunity as national governments – and more direct influence.

The scientists assembled their list of 13,000 cities from data from 187 of the world’s nations. Altogether 195 nations in 2015 in Paris agreed to work together to contain global warming, driven by fossil fuel use and consequential increases in atmospheric carbon dioxide, to, if possible, no more than 1.5°C above historic levels by 2100.

In fact, the world has already warmed by around 1°C on average in the last century: the challenge is to act in time to stop global warming rising to catastrophic levels.

Several surprises

And the new study delivers some useful places to begin. The top 100 cities are home to only 11% of the world’s population but drive 18% of the global carbon footprint.

The top three – Seoul in Korea, Guangzhou in China and New York in the US – are no surprise, but other metropolitan areas with unexpectedly large carbon footprints include Cologne in Germany, Manchester in the UK and Montreal in Canada.

Of the top 200, 41 cities – and these include Cairo in Egypt, Dhaka in Bangladesh and Lima in Peru – are in countries where both total emissions and emissions per head are low. But many of the world’s most carbon-intensive cities are in the world’s richest nations: that is, their civic authorities have the resources with which to act.

“The fact that carbon footprints are highly concentrated in affluent cities means that targeted measures in a few places and by selected coalitions can have a large effect covering important consumption hotspots,” said Dr Moran. – 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

China’s trade plan may cause lasting harm

China’s trade plan could cause  environmental catastrophe, scientists warn, because of its voracious appetite for natural resources and its climate impact.

LONDON, 1 June, 2018 – Possibly the most ambitious and far-reaching development scheme ever launched, China’s trade plan, the Belt and Road Initiative (BRI), may pose an unacceptable risk to the environment, scientists say.

Launched in 2013, the BRI plans a huge expansion of trade routes linking Asia, Africa and Europe, involving China itself and 64 other countries, and affecting about two thirds of the world’s people and one third of its economy. There will be new ports on the Pacific and Indian Ocean coasts, new roads, and a rail network linking China to north-west Europe.

But an international group of scientists, writing in the journal Nature Sustainability, expresses serious doubts about the possibility of completing the scheme without causing permanent environmental damage.

Economy vs. environment

The scientists write: “Economic development aspirations under the BRI may clash with environmental sustainability goals, given the expansion and upgrading of transportation infrastructure in environmentally sensitive areas, and the large amounts of raw material needed to support that expansion…

“If not properly addressed, the negative environmental impacts of the BRI are likely to disproportionately affect the world’s poor, hence putting at risk the wellbeing of the very people it aims to help.”

Some of the scientists’ comments are positive. They say, for instance, that the BRI includes “examples of well-planned road developments” with negligible impacts on wildlife and protected areas.

They cite the proposed Serengeti Highway in Tanzania, which would go round the national park, not through it. An alternative route for Nigeria’s planned Cross River Superhighway will cause far less environmental harm than the original scheme, and the Bangladesh Railway is improving the protection of elephants by building five overpasses across the tracks for them at well-used crossing points.

“In biodiversity and environmental terms, it’s the worst thing we’ve seen anywhere  –  and in the past forty years, I and my colleagues have seen some pretty horrific stuff”

To improve the BRI’s research and monitoring, Beijing has announced its intention to build a Digital Silk Road with the Chinese Academy of Sciences, a potential boost to environmental research elsewhere in Asia.

But despite these expected benefits from the BRI, doubts remain. The scientists say a recent report by the World Wildlife Fund found “a clear risk of severe negative environmental impacts from infrastructure developments”.

These include the scheme’s gargantuan appetite for natural resources, including sand and limestone for making the immense quantities of concrete and cement that it will demand. Global sand extraction, the scientists say, has already passed its natural renewal rate, causing severe damage to deltas and coastal ecosystems.

And with China already responsible for one-third of global greenhouse gas emissions, the vast pipeline network planned under the BRI, and the infrastructure construction involved, will mean further and faster exploitation of fossil fuel reserves.

Riskiest scheme ever

One of the authors of the commentary in Nature Sustainability is Bill Laurance, of James Cook University, Australia. In an interview with Nexus Media he had more to say about his concerns – and he didn’t pull his punches.

Professor Laurance thinks the BRI “environmentally, the riskiest venture ever undertaken”, which “simply blows out of the water anything else that’s been attempted in human history…In biodiversity and environmental terms, it’s the worst thing we’ve seen anywhere  –  and in the past forty years, I and my colleagues have seen some pretty horrific stuff in the Amazon, Africa, Southeast Asia and the South Pacific.”

On climate change, he holds out little hope that the Initiative can offer anything much: “If you also consider everything China is doing or promoting overseas in terms of extractive industries and large-scale infrastructure, they utterly overwhelm any other nation as climate changers.

“In real terms – digging through a great deal of greenwashing – I don’t see anything in the BRI that squares with China’s stated climate goals.” – Climate News Network

US economy risks China’s climate impact

In this globalised world China’s climate impact could hit America’s economy, as one country’s calamities indirectly harm other nations. The losses could grow.

LONDON, 30 May, 2018 – German scientists have shown once again that climate change remains a global problem, with China’s climate impact, for instance, hurting the economy of the United States. Disastrous flooding – likely to increase as the world warms, and ever more water enters the atmosphere – in one country could reverberate in ways that could harm another nation’s economy.

More precisely, China alone could experience a total of $380bn in economic losses over the next 20 years: this adds up to about 5% of the nation’s annual economic output.

About $175 billion of total losses could be attributed to future climate change – and as these losses are passed down the global trade and supply network, the US and the European Union could be most affected.

If so, river flooding in China alone – aside from the ever-greater extremes of heat and windstorm that are predicted to arrive with higher temperatures – could bring US losses of up to $170 billion in the next 20 years.

“Trump’s tariff sanctions are likely to leave the US economy even more vulnerable to climate change”

“The EU will suffer less from indirect losses caused by climate-related flooding in China due to its even trade balance. They will suffer when flooded regions in China temporarily fail to deliver for instance parts that European companies need for their production, but on the other hand Europe will profit from filling climate-induced production gaps in China by exporting goods to Asia.

“This yields the European economy currently more climate-prepared for the future,” said Sven Norman Willner, of the Potsdam Institute for Climate Impact Research, who led the study.

“In contrast, the US imports much more from China than it exports to this country. This leaves the US more susceptible to climate-related risks of economic losses passed down along the global supply and trade chain.”

He and his co-authors report in the journal Nature Climate Change that they took a look at the economic challenge for the world as a whole in the limited case of river flooding: damage caused by human-induced climate change, as a consequence of the combustion of fossil fuels at a rate that has already begun to change the chemistry of the atmosphere, could become a significant factor in the global economy, and river flooding has always been a problem.

Heat rises by 1°C

But as temperatures rise – and they have already risen by a global average of about 1°C in the last century, as ever more greenhouse gases have reached the atmosphere – so does evaporation, and so does the capacity of the atmosphere to hold moisture, which must eventually fall as rain.

The researchers looked at projections of near-future flood hazards on a regional scale that humans could expect to see on the basis of greenhouse gases already emitted. They then incorporated what is already known about economic network response to river flooding and its effects, taking into account the dynamics of international trade.

In research of this kind, the Potsdam Institute has what racing tipsters call “form.” One of the researchers, Anders Levermann, has already warned that greenhouse gases are forcing up sea levels; that warming carries with it global economic threats; and that the numbers of humans at risk from the worst of the future floods are rising.

The news is not all bad: climate change could also bring more rain to the countries of the African Sahel, but the same changes could mean ever higher levels of hurricane damage in the US.

Complicated prospect

The latest study has its own complexities: much depends on the course of international trade and the capacity of those countries not flooded to make good the shortfalls that follow flood disasters in one river system. In essence, international relations and natural hazard vulnerabilities have become entangled.

The entanglement remains, even though America’s President Trump has imposed tariffs to protect US industry. Unless nations adapt further, climate change will accelerate flood losses worldwide by about 15%, to a global total of $600bn within the next two decades. China’s losses could increase by 82%. America will still feel the shock, the researchers say.

“We find that the intensification of the mutual trade relation with China leaves the EU better prepared against production losses in Asia than the US. The prospect that the US will be worse off can be traced back to the fact that it is importing more products from China than it is exporting,” said Professor Levermann.

“Interestingly, such an unbalanced trade relation might be an economic risk for the US when it comes to climate-related economic losses. In the end, Trump’s tariffs might impede climate-proofing the US economy.”

He went on: “Trump’s tariff sanctions are likely to leave the US economy even more vulnerable to climate change. As our study suggests, under climate change, the more reasonable strategy is a well-balanced economic connectivity, because it allows to compensate economic damages from unexpected weather events – of which we expect more in the future.” – Climate News Network

Warming world makes noses run

Summer is the worst time for many allergies that make noses run and sufferers feel below par. They’re causing widespread misery just now.

LONDON, 29 May, 2018 – Eyes streaming in the warm weather? Does your nose run; does it itch? Do your ears hurt, do you have a general feeling of malaise?

Climate change is likely to be one of the causes of what is considered to be among the most difficult years ever in North America for those who suffer from a range of spring and summertime allergies.

An abundance of pollen in the air – leading to what specialists term an “allergy explosion” in many regions – is causing widespread discomfort and, for some, serious health problems. Severe sinusitis and what’s generally referred to as hay fever are the most common manifestations of pollen allergy.

Areas in the south of the US, in the states of Louisiana and Georgia, and in central regions such as Nebraska and Kansas, are said to be worst affected.

“Warmer temperatures caused by climate change are really causing longer growing seasons and more intense release of pollen”, says Kenny Mendez, president of the Asthma and Allergy Foundation of America. Pollen from various grasses, plants and trees can all cause big problems for allergy sufferers.

“The influence of climate change on plant behaviour exacerbates or adds an additional factor to the number of people suffering from allergy and asthma”

Pollen from ragweed or Ambrosia artemisiifolia, a weed native to the US and found throughout the country, is considered to be one of the main reasons for a big upsurge in allergies.

US plant specialists say that, mainly because of changes in climate, including warmer, wetter winters, the pollen-producing season of ragweed increased by nearly a month in the 20-year period to 2015.

This is very bad news for allergy sufferers: one ragweed plant can produce a billion grains of pollen in one growing season, and the pollen can be blown on the wind for hundreds of miles.

Other parts of the world are also on ragweed alert. The plant has been spreading across warmer regions of Europe for the past 50 years.

Twelve-fold increase

Researchers at the University of Leicester in the UK found ragweed pollen levels on some days over a recent summer in the English Midlands were enough to cause severe hay fever and asthma attacks.

EU scientists who worked on the Atopica project, examining the relationship between land use, air quality and climate, found that a combination of warmer winters due to climate change and the spread of invasive ragweed could result in a twelve-fold increase in pollen levels in some parts of Europe by mid-century.

A comprehensive Europe-wide ragweed eradication programme – and action to combat climate change – are vital in order to tackle the ragweed problem, say plant specialists.

Increased allergy rates are due not only to changes in climate and the worldwide spread of various plant species.

Too protective

Air pollution – much of it caused by  climate-changing greenhouse gases from power stations and other industrial facilities – is another factor leading to more allergies. Health professionals say a tendency in the developed world to over-protect children and “over-sanitise” their environments is also to blame; such protective behaviour means immune systems fail to be strengthened.

But scientists are becoming increasingly aware of the critical impact climate change is having on the growing cycle of plants – and on health.

“The influence of climate change on plant behaviour exacerbates or adds an additional factor to the number of people suffering from allergy and asthma”, says Lewis Ziska, a weed ecologist at the US Department of Agriculture, quoted by the Union of Concerned Scientists in the US.

Left unchecked, says Ziska, rising carbon dioxide levels and further warming pose serious risks for allergy sufferers. – Climate News Network