Greenhouse gas-guzzlers spurn extra carbon dioxide

Greenhouse gas-guzzlers spurn extra carbon dioxide

Minutely small marine plants called diatoms mitigate climate change by consuming carbon dioxide and producing oxygen. But they may reject the rising levels of the greenhouse gas.

LONDON, 1 July, 2015 – Diatoms – those tiny ocean-dwelling photosynthesisers that produce a fifth of the planet’s oxygen each year – may not gulp down more carbon dioxide more enthusiastically as greenhouse gas levels in the atmosphere continue to rise.

Instead, they may switch off and use the gas more efficiently. If so, the consequences for the rest of the planet could be uncomfortable.

Climate scientists who try to model the machinery of the atmosphere have always banked on a “fertilisation effect” from at least some of the extra CO2 pumped into the atmosphere by the human burning of fossil fuels and the clearance of the forests. They may no longer be able to do so.

The discovery – reported in Nature Climate Change – is based on laboratory experiments with one single-celled phytoplankton species called Thalassiosira pseudonana and meticulous study of its genetic mechanisms.

Rising concentrations

It may not be a sure guide to what actually happens in the crowded, complex world of climate change later this century. But all phytoplankton are survivors of the same evolutionary history, and many of them are known to be equipped with carbon-concentrating mechanisms to make the most of the available carbon dioxide in the atmosphere. So what happens to one could be true for all.

Gwenn Hennon, an oceanographer at the University of Washington in Seattle, US, and colleagues decided to work out what happened to their laboratory diatoms in atmospheres in which carbon dioxide levels continued to rise to 800 parts per million later this century.

Right now, the concentration is almost 400 parts per million, but for most of human history until the invention of the internal combustion engine, and the exploitation of fossil fuels, it has been around 280 parts per million. A third of the emissions from factory chimneys and motor exhausts is absorbed by living things in the oceans, starting with diatoms and other phytoplankton.

The Seattle team found that while many photosynthesisers do grow faster with more CO2, the oceanic diatoms did not: they responded vigorously at first, but as long as there was a normal supply of other nutrients, over 15 generations, they slowed down.

Slow response

“There are certain genes that respond right away to a change in CO2, but the change in the metabolism doesn’t actually happen until you give the diatoms some time to acclimate,” said Hennon, a doctoral student. “Instead of using that energy from the CO2 to grow faster, they just stopped harvesting as much energy from light through photosynthesis and carried out less respiration.”

Studies like this are an illustration of the intricacy and complexity of climate science. How the living world responds to greater human emissions of carbon dioxide from fossil fuels is key to all models of future climates, but researchers in general have expected the plant world to respond by consuming more, and slowing the rate of change overall.

There is some evidence that this is happening. Half of all the anthropogenic or human-made CO2 has been gulped down in the form of more lusty growth by vegetation, but this “negative feedback” effect has been countered by other factors: more greenery in the Arctic, for instance, could accelerate global warming, and anyway, as plants grow more vigorously, so do plant predators.

And increasingly, climate scientists have begun to realise that although the responses of the forests and arid lands  are vital factors, the big players could be the creatures hardly anyone ever sees: the fungi and tiny fauna in the soil  beneath the trees, and of course the phytoplankton in the oceans.

Oxygen creators

The Seattle calculation is that the evolutionary history of the diatoms explains the carbon-concentrating mechanisms in their genetic inheritance. Microbes are life’s foundation, and single-celled creatures evolved over three billion years when CO2 levels in the atmosphere were at colossal concentrations.

The diatoms and their ancestors were the creatures that created the oxygen atmosphere in which all other complex living things evolved. An enzyme evolved to help the first microbes cope with high levels of CO2, and has survived for billions of years.

“There hasn’t been another enzyme to replace it since, so plants and algae that photosynthesise have an enzyme that functions better at a higher CO2 level than we currently have,” Hennon said.

“When the CO2 remains high for a long time, however, the diatoms make a more radical metabolic shift. They decrease photosynthesis and respiration to balance the cell’s energy budget. In other words, the diatoms use less energy to grow at the same rate.” – Climate News Network

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Alaska’s glaciers melt faster as climate change speeds up

Alaska's glaciers melt faster as climate change speeds up

Climate change rather than natural causes is the main cause of Alaska’s glacier loss, which is set to speed up, US scientists say.

LONDON, 30 June, 2015 – The glaciers of Alaska are melting and retreating: the chief cause is climate change and the loss of ice is unlikely to slow, according to a new study by US scientists.

They calculate that the frozen rivers of the Pacific coast of America’s northernmost state are melting fast enough to cover the whole of Alaska with 30 cms of water every seven years.

Since Alaska is enormous – it covers 1.5 million square kilometres and is the size of California, Texas and Montana put together – this adds up to a significant contribution to sea level rise.

“The Alaska region has long been considered a primary player in the global sea level budget, but the exact details of the drivers and mechanisms of Alaska glacier change have been stubbornly elusive,” said Chris Larsen, a geophysicist at the University of Alaska Fairbanks, and lead author of a study in Geophysical Research Letters.

Taxonomy of change

Scientists from the University of Alaska and the US Geological Survey analysed studies of 116 glaciers in the Alaska region over a 19-year-period to estimate the rate at which ice melted and icebergs calved.

They used airborne lidar remote sensing technology and other techniques, historical data and a global glacier inventory to establish a kind of taxonomy of glacier change.

The Columbia Glacier in Prince William Sound had retreated more than 19 kilometres because of iceberg calving and had thinned by 450 meters in height since 1980. But, unexpectedly, tidewater glaciers – those that end in the ocean – seemed to make comparatively little contribution to sea level rise.

“Instead we show that glaciers ending on land are losing mass exceptionally fast, overshadowing mass changes due to iceberg calving, and making climate-related melting the primary control on mountain glacier mass loss,” Dr Larsen said.

Big contributor

He and his colleagues calculated that Alaska is losing ice at the rate of 75 billion metric tons a year. Such research is just one more piece of careful cross-checking in the great mosaic of climate research: another systematic confirmation that overall, glaciers are not losing ice in response to some natural cycle of change of the kind that occasionally confuses the picture for climate science.

The agency at work is largely global warming as a response to the steady rise in atmospheric carbon dioxide as a consequence of the burning of fossil fuels.

Mountain glaciers represent only 1% of the total ice on the planet: the other 99% is found in Greenland – which is melting fast – and in the great frozen continent of Antarctica, where ice mass is being lost at an increasing rate.

But although the mountains of the temperate and tropic zones bear only a tiny percentage of the planet’s ice, their melting accounts for almost a third of the sea level rise currently measured by oceanographers, and this melting will go on to become a big contributor to the sea levels later this century.

“Alaska will continue to be a major driver of sea level change in the upcoming decades”

Across the border in Canada, glaciologists have warned that the country will lose a huge volume of flowing ice, and while one team has confirmed that air pollution rather than global warming long ago began to strip Europe’s Alps of their glaciers, in general mountain peaks are warming faster than the valleys and plains below them.

Geophysicists and glaciologists have established that the glaciers of the tropical Andes are at risk, and in the Himalayan mountain chain glaciers seem to be in inexorable retreat with consequences that could be devastating for the many millions in the Indian subcontinent and in China who rely on seasonal meltwater for agriculture.

Glaciers are by definition hard to study – they are high, cold and in dangerous terrain – and such research is inevitably incomplete: the scientists for instance excluded glaciers smaller than three square kilometres. But together these small patches of flowing ice account for 16% of Alaska’s glaciated landscape. The 116 glaciers in the survey together added up to only 41% of the state’s glaciated area.

But the pattern established by the Fairbanks team suggests that melting will accelerate with climate change. “Rates of loss from Alaska are unlikely to decline, since surface melt is the predominant driver, and summer temperatures are expected to increase,” said Dr Larsen.

“There is a lot of momentum in the system, and Alaska will continue to be a major driver of sea level change in the upcoming decades.” – Climate News Network

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Renewable energy redoubles its global reach

Renewable energy redoubles its global reach

As the world economy and energy use both grew in 2014, renewables continued their rapid rise but carbon emissions did not. 

LONDON, 27 June, 2015 − A significant threshold has been crossed by renewable energy as analysts report that the sectorʼs size last year reached double the level it was at just 10 years earlier.

This expansion happened in a year when the global economy and energy use both grew, but without a matching rise in emissions of carbon dioxide − the main greenhouse gas targeted in efforts to restrain global warming.

The report by REN21, a global renewable energy policy network, says the result is an example of sustainable development. Despite the worldʼs annual 1.5% increase in energy consumption in recent years and 3% GDP growth last year, 2014ʼs CO emissions were unchanged from 2013ʼs total of 32.3 billion tonnes.

The reportʼs authors say this decoupling of economic and CO growth is due to Chinaʼs increased use of renewables and to efforts by OECD countries to promote more sustainable growth, including by increased energy efficiency and use of renewable energy.

“Renewable energy and improved energy efficiency are key to limiting global warming to 2°C and avoiding dangerous climate change,” says Arthouros Zervos, who chairs REN21.

Distorting subsidies

Solar, wind and other technologies, including large hydro-electric schemesused in 164 countries added another 135 Gigawatts last year to bring the worldʼs total installed renewable energy power capacity to 1,712 GW. This was 8.5% up on 2013, and more than double the 800 GW of capacity recorded in 2004. One GW can power between 750,000 and one million typical US homes.

The authors say the sectorʼs growth could be even greater were it not for more than US$550 bn paid out in annual subsidies for fossil fuels and nuclear energy. They say the subsidies keep the prices for energy from these fuels artificially low, encouraging wasteful use and hindering competition.

Infographic: REN21

Christine Lins, executive secretary of REN21, says: “Creating a level playing field would strengthen the development and use of energy efficiency and renewable energy technologies. Removing fossil fuel and hidden nuclear subsidies globally would make it evident that renewables are the cheapest energy option.”

By the end of 2014, renewables comprised an estimated 27.7% of the worldʼs power generating capacity − enough to supply an estimated 22.8% of global electricity demand.

The amount of electricity available from renewables worldwide is now greater than that produced by all coal-burning plants in the US. Coal supplied about 38% of US electricity in 2013, compared with around 50% in the early 2000s.

Solar photovoltaic capacity has had a rapid 68-fold growth, from 2.6 GW in 2004 to 177 GW in 2014, while wind power capacity has increased eightfold, from 48 GW in 2004 to 370 GW in 2014. Employment in the sector is also growing fast, with an estimated 7.7m people worldwide working directly or indirectly on renewable energy last year.

Outpacing fossil fuels

New investment globally in renewable power capacity was more than twice that of investment in net fossil fuel power capacity, continuing the trend of renewables outpacing fossil fuels in net investment for the fifth year running.

Investment in developing countries was up 36% from the previous year, to $131.3 bn. It came closer than ever to overtaking the investment total for developed economies, which reached $138.9 bn in 2014 − up only 3% from 2013.

China accounted for 63% of developing country investment, with Chile, Indonesia, Kenya, Mexico, South Africa and Turkey each investing more than $1bn. By dollars spent, the leading countries for investment were China, the US, Japan, the UK and Germany. Leading countries for investments relative to per capita GDP were Burundi, Kenya, Honduras, Jordan and Uruguay.

But REN21 points out that more than a billion people − 15% of humanity − still lack access to electricity, and the entire African continent has less power generation capacity than Germany.

The report says that off-grid solar PV has “a significant and growing market presence”, and other distributed renewable energy technologies are improving life in remote off-grid areas.

However, it stresses that this growth rate is still not enough to achieve the Sustainable Energy for All (SE4ALL) goals of doubling renewable energy and energy efficiency, and providing universal access for all by 2030. − Climate News Network

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Prospect of warmer winters doesn’t mean fewer deaths

Prospect of warmer winters doesn’t mean fewer deaths

New scientific study pours cold water on the theory that mortality rates will drop in winter months as the climate warms.

LONDON, 26 June, 2015 − Global warming is unlikely to mean that fewer people in northern latitudes will die from cold during the winter, according to a study by scientists in the US.

Despite arguments that an increase in death rates caused by global warming and increased summertime temperatures will be offset by a matching drop in mortality as winter temperatures also rise, the study cautions against assuming any such link as research suggests otherwise.

The study, carried out over several years, looked at temperature-related seasonal mortality rates, particularly among elder people, in a total of 39 cities – the majority in the US, and three in France.

It concludes: “Our findings suggest that reductions in cold-related mortality rates under a warming climate may be much smaller than some have assumed.”

The research, carried out by a team led by Professor Patrick Kinney, a specialist in public health at the Columbia University Earth Institute in the US, is published in the Environmental Research Letters journal.

Temperature range

“We found that excess winter mortality did not depend on seasonal temperature range and was no lower in warmer vs colder cities, suggesting that temperature is not a key driver of winter excess mortality,” the study says.

Although the researchers acknowledge that seasonal temperature patterns can have an effect on health, many other factors influence mortality rates in winter among elderly people.

Diseases such as influenza – often transmitted when younger generations of families meet up with their elders at family celebrations – play a far greater role in mortality than the cold.

“Most older people who die over the winter don’t die from cold – they die from complications related to ’flu and other respiratory diseases,”  Kinney says.

Most previous studies investigating the links between temperature rises and death rates have focused on the impact of summer heat.

“Most older people who die over the winter don’t die from cold – they die from complications
related to respiratory diseases”

A prolonged heatwave across Europe in 2003 – which many scientists say can be attributed to climate change – is believed to have caused between 30,000 and 50,000 deaths. Elderly people in urban areas – often left stranded in their baking apartment blocks – were particularly badly hit.

A lot of media attention has also been given recently to the high rates of death among migrant workers from Nepal working in high temperatures in Qatar and other countries in the Gulf region.

The Columbia study looked at winter death rates among elderly people in cities in different climate zones and with differing demographics – from Paris and New York to Miami and Marseilles.

Opposite effect

It found that most of the elderly people living in the cities from which data was gathered were not exposed to the winter cold for long periods as the majority had access to a warm indoor environment.

Kinney says that rather than decreasing mortality, warmer winters could have the opposite effect.

“We see mosquito-borne diseases emerging in new territories because warmer winter temperatures enable the insects to over-winter in more northerly regions,” he says.

“Warmer temperatures can also enable an insect-borne virus to replicate inside the insect vector to be transmitted and cause disease in a human or animal.

“Sadly, this research tells us that an increase in summer deaths due to climate change is unlikely to be counteracted by a reduction in winter deaths.” – Climate News Network

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Court tells Dutch government it must cut back emissions

Court tells Dutch government it must cut back emissions

In a landmark ruling, the law has stepped in to demand that the Netherlands does more to tackle the imminent danger of climate change.

LONDON, 25 June, 2015 – A Dutch court has made history by ordering the Netherlands government to make deeper cuts than it is planning in its emissions of greenhouse gases.

The district court in The Hague − in its landmark legal requirement that a state should take precautions against climate change − said the government must “do more to avert the imminent danger caused by climate change”.

The court ruled that the Netherlands should, by 2020, reduce its CO2 emissions by at least 25% on their 1990 levels. The government is planning cuts of around 16%, but Denmark and Germany are already on course to cut their CO2 emissions by 40% by 2020.

The case was brought by the Urgenda Foundation – an NGO focused on the transition towards a sustainable society using only renewable energy − and nearly 900 co-plaintiffs.

Already suffering

Marjan Minnesma, director of Urgenda, said: “Millions of people who are already suffering the consequences of climate change are hoping that we, the people that have caused the emissions and have the means to reduce them, will intervene while there is still time.”

Comparable legal cases are being prepared in Belgium, Norway, the Philippines and Peru.

Urgenda says its arguments are supported by the Oslo Principles, which say that states have the legal obligation to avert dangerous climate change.

Carroll Muffett, the president and CEO of the Centre for International Environmental Law, said: “At the heart of this landmark case lies a simple, terrible truth: in failing to take ambitious action to confront climate change, the government of the Netherlands is threatening the lives, the well-being and the human rights of its own citizens.”

He added: “The case reflects a growing awareness among people worldwide that the failure to act on climate change violates fundamental principles of human rights.”

It is a precedent-setting judgement, though I think in a year or so it will not seem at all exceptional

Professor Muffett told the Climate News Network that the judgement was especially significant for what the court had said about human rights, and about the responsibility the Dutch government owed to future generations.

“A decision of this kind from any court sends an important signal,” he said. “States and polluters should take careful note.

“There is a growing movement of climate litigation around the world, a challenge to inertia. Climate change cannot wait.

Extremely careful

“The ruling is extremely careful, thoughtful − and narrow. It says the risks of acting to mitigate climate change are less than the risks of trying to adapt to it, and it insists that the Dutch government has a duty to mitigate it.

“It is a precedent-setting judgement, though I think in a year or so it will not seem at all exceptional.”

Some thought the court had not gone far enough. Wendel Trio, director of Climate Action Network Europe, said: “The task specified by the ruling is not too challenging. The target should be much higher than 25% in order to be truly in line with what is needed to tackle climate change.”

However, Professor Muffett thinks the judgement will be hugely influential. He said: “Governments, especially in Europe, will be going to the UN’s Paris climate negotiations in November very cognisant of what this court has said. The context on the road to Paris is changing fast.” – Climate News Network

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Global warming is accelerating loss of species

Global warming is accelerating loss of species

Human-induced climate change adds to threats vertebrates face from hunting and habitat loss as researchers warn that modern extinction rates are exceptionally high.

LONDON, 24 June, 2015 – Biologists have once again confirmed their own worst fears – that humans have launched a new phase of mass extinction.

There have been five catastrophic episodes in the 500 million-year history of complex life, and humanity has now precipitated a sixth, according to a new study.

Gerardo Ceballos, a researcher in the Department of Ecology Biodiversity at the National Autonomous University of Mexico, and colleagues report in the journal Science Advances that their calculations are based on the most conservative possible estimates of extinction in recent human history.

They compared those with the calculated “background”, or normal, rate of extinction throughout evolution, and came to the conclusion that vertebrate species are slipping away into the eternal night at least 114 times faster than they would if there were no humans around to hunt them, destroy their habitats or change the climates in which they had evolved.

Potentially calamitous

All such stories fall into the “stop me if youʼve heard this one” category. For more than two decades, zoologists in particular have repeatedly warned of potential calamitous extinction rates.

They have reasoned that the pressures already driving down animal populations are likely to be made worse by global warming due to the burning of fossil fuels – either by moving the climatic zones to which the creatures are adapted faster than they can migrate, or by simply becoming too warm overall, which is something that happened 55 million years ago.

One recent study even linked atmospheric levels of carbon dioxide with the worst event of all, the “Great Dying” of the Permian period 252 million years ago.

“We can confidently conclude that modern extinction rates . . . suggest a mass extinction
is under way”

But there has always been a problem of numbers – in fact, two problems of numbers. Biologists have no sure idea of how many species inhabit the planet today, and they have great difficulty establishing that any particular animal is really extinct, as opposed to just rare and difficult to identify.

So Dr Ceballos and his co-researchers went back and did the sums again, working from a recent estimate of the background rate of extinction of two mammal extinctions per 10,000 species per century.

They looked at all the written evidence for recent extinctions – the dodo of Mauritius, Steller’s sea cow, the Rodrigues giant tortoise, and all the other amphibians, birds, reptiles, fish and mammals that have slipped away to oblivion, first since 1500 and then since 1900. And the researchers then chose conservative and highly conservative calculations of loss.

Creatures vanishing

They found that, even using the most generous estimates of “normal” extinction, and the most highly conservative calculations of present loss, based on data from the 2014 International Union for Conservation of Nature’s Red Listthey had evidence that creatures are now vanishing at more than 100 times the background rate.

Almost all human health and wealth is based on what grows in the ground or grazes upon it. If the loss goes on, then within as little as three human lifetimes, humanity as a species could be deprived, the researchers warn, of “many biodiversity benefits”.

With this research, they say they have placed a “lower bound” on humanity’s impact on all other living things.

They conclude: “Although biologists cannot say precisely how many species there are, or exactly how many have gone extinct in any time interval, we can confidently conclude that modern extinction rates are exceptionally high, that they are increasing, and that they suggest a mass extinction is under way – the sixth of its kind in Earth’s 4.5 billion years of history.” – Climate News Network

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Combating climate dangers is seen as medical emergency

Combating climate dangers is seen as medical emergency

International experts say the last 50 years of health advances worldwide will be jeopardised unless urgent steps are taken to confront climate change.

LONDON, 23 June, 2015 – The threat that climate change poses to human health is so great that it could undermine the last half-century of gains in development and global health, says an international commission of medical experts.

One author, fiercely critical of international efforts to confront the problem, says it is a medical emergency that demands an emergency response.

More hopefully, though, the group’s report says that international efforts to tackle climate change – “the defining challenge of our generation” – represent one of the greatest opportunities to improve health worldwide this century.

The report, published in The Lancet medical journal, is the work of the 2015 Lancet Commission on Health and Climate Change.

Unparalleled chance

It says many responses to climate change have direct and indirect health benefits – from reducing air pollution to improving diet – and so efforts to reduce the threat offer an unparalleled chance for far-reaching gains in health.

But the commission is under no illusions about what is at stake. The authors say the potentially catastrophic risk to human health posed by climate change has been underestimated

They add – in a familiar refrain – that while the technologies and finance required to address the problem do exist, the global political will to implement them is lacking.

Professor Hugh Montgomery, one of the commission’s co-chairs and director of the University College London (UCL) Institute for Human Health and Performance, UK, says: “Climate change is a medical emergency. It thus demands an emergency response, using the technologies available right now.

“Under such circumstances, no doctor would consider a series of annual case discussions and aspirations adequate, yet this is exactly how the global response to climate change is proceeding.”

“Now is the time for us to lead the way in responding to another great threat to the human and environmental health of our generation

Lancet Commission on Health and Climate Change

Image: The Lancet Commission on Health and Climate Change

Professor Anthony Costello, another of the commission’s co-chairs and director of the UCL Institute for Global Health, says: “Climate change has the potential to reverse the health gains from economic development that have been made in recent decades – not just through the direct effects on health from a changing and more unstable climate, but through indirect means such as increased migration and reduced social stability.”

The report says the direct health impacts of climate change come from the increasing frequency and intensity of extreme weather events, especially heatwaves, floods, droughts and storms. Indirect impacts result from changes in infectious disease patterns, air pollution, food insecurity and malnutrition, involuntary migration, displacement and conflicts.

It says there are many ways in which action on climate change brings immediate health gains. For example, burning fewer fossil fuels reduces respiratory diseases, and what doctors call “active transport” (walking and cycling) cuts pollution and traffic accidents, and reduces rates of obesity, diabetes, coronary heart disease and stroke. There are also health benefits from changes to diet, such as eating less red meat.

Entrenched interests

The commission is an extensive collaboration between experts from Europe and China. Its other co-chair, Professor Peng Gong, from Tsinghua University, Beijing, says: “The health community has responded to many grave threats to health in the past.

“It took on entrenched interests such as the tobacco industry, and led the fight against HIV/AIDS. Now is the time for us to lead the way in responding to another great threat to the human and environmental health of our generation.”

The report provides a set of recommendations for policy-makers, and the authors propose the formation of a new global independent body on climate change and health − to be called Countdown to 2030: Climate Change and Health Action − to monitor and report every two years on the health impacts of climate change. – Climate News Network

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Rise in CO2 could restrict growing days for crops

Rise in CO2 could restrict growing days for crops

While plants in temperate zones may benefit from higher temperatures, global warming’s impact in the tropics threatens catastrophe for food security.

LONDON, 20 June, 2015 − The positive consequences of climate change may not be so positive. Although plants in the colder regions are expected to thrive as average global temperatures rise, even this benefit could be limited.

Some tropical regions could lose up to 200 growing days a year, and more than two billion rural people could see their hopes wither on the vine or in the field. Even in  temperate zones, there will be limits to extra growth.

Plants quicken, blossom and ripen as a response to moisture, warmth and the length of daylight. Global warming will clearly change the temperatures and influence the patterns of precipitation, but it won’t make any difference to the available hours of sunlight at any point on the globe.

Scientists at the University of Hawaii at Mānoa report in the Public Library of Science journal PLOS Biology that they looked at the big picture of complex change. Higher concentrations of atmospheric carbon dioxide – the greenhouse gas from car exhausts, forest fires and factory chimneys – are expected overall to aid crop and forest growth.

Extended season

Average global warming of less than 1°C in the last 30 years has extended the northern hemisphere growing season by up to 11 days, but plants are still limited by radiation.

“Those that think climate change will benefit plants need to see the light, literally and figuratively,” says Camilo Mora, lead author of the report and assistant professor in the Department of Geography at the University of Hawaii.

“A narrow focus on the factors that influence plant growth has led to major underestimations of the potential impacts of climate change on plants, not only at higher latitudes but more severely in the tropics, exposing the world to dire consequences.”

Professor Mora has made a career of thinking about global consequences. He and colleagues recently tried to calculate the possible dates at which local climates could shift inexorably in different parts of the world, and tried also to build a picture of how ocean warming and acidification would affect incomes everywhere.

“Many plants will not be able to take advantage of those warmer temperatures because there will not be enough sunlight to sustain their growth”

His team is not the first to try to calculate the potential impact of catastrophic global warming on global food supply. Cereals are vulnerable to extremes of heat, and climate change may already be affecting yields in Europe.

But the Hawaiian scientists tried a simple theoretical approach, by first identifying the ranges of temperature, soil moisture and light that drive 95% of the world’s plant growth today.

They then tried to calculate the number of days in a year in which these growth conditions could be expected at various latitudes in the future, as carbon dioxide levels – and average temperatures – climb.

They found that, nearer the poles, the number of days above freezing would increase by 7%.

“But many plants will not be able to take advantage of those warmer temperatures because there will not be enough sunlight to sustain their growth,” says Iain Caldwell, of the Hawaii Institute of Marine Biology.

The same warming at the lowest latitudes could be devastating: in some tropical regions, conditions could become too hot and dry for any growth.

Overall, the planet could see an 11% reduction in the number of days suited to growth, and some places in the tropics could lose 200 growing days a year.

Although some regions in China, Russia and Canada will see an improvement, around 2.1 billion people who rely on forests and agriculture for food and revenue could lose 30% of the days they now bank on for plant growth.

But rising levels of carbon dioxide could also affect the quality of plant growth, according to a new study in Global Change Biology.

Zhaozhong Feng, of the Department of Biological and Environmental Sciences at the University of Gothenburg, Sweden, and colleagues looked at the results of eight experiments in four continents on crops, grasslands and forests, and found that as carbon dioxide levels go up, the nitrogen content of the crop is lowered. In the case of wheat and rice, this would also mean lower protein levels.

Negative effect

“Furthermore, we can see that this negative effect exists regardless of whether or not the plants’ growth increases, and even if fertiliser is added,” says Johan Uddling, a plant physiologist at Gothenburg, and a co-author of the report. “This is unexpected and new.”

In the same week, a team of scientists at the University of Alaska Fairbanks produced evidence that climate change has already begun to alter the forests of the far north.

They report in the journal Forest Ecology and Management that in the interior of Alaska, already at the optimum temperature range for white spruce, tree growth slowed as summer temperatures rose.

In Western Alaska, once at the low end of the ideal temperature range for the same species, trees are now growing more rapidly.

“For the first time across a major forest region, we have real data showing that biome shift has started”, said Glenn Juday, professor of forest ecology at the university’s School of Natural Resources.

“This is not a scenario model, or a might, or a maybe. The boreal forest in Interior Alaska is very near dying from unsuitably warm temperatures. The area in Western Alaska where the forest transitions to tundra is now the productive heart of the boreal forest.” − Climate News Network

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Climate change offers rare respite for African farmers

Climate change offers rare respite for African farmers

A surprise effect of greenhouse gases is that changes in air temperature and wind patterns are increasing rainfall and crop yields in the drought-prone Sahel region.

LONDON, 18 June, 2015 − A wide belt of tropical Africa is enjoying higher rainfall than for decades past, boosting harvests and keeping the threat of drought at bay. And the main factor, according to new research, is climate change.

Drought killed at least 100,000 people in the Sahel region south of the Sahara desert over a period of about 15 years from the late 1960s, but scientists in the UK report that summer rainfall was 0.3 mm (0.01 inches) a day higher from 1996-2011 than from 1964 to 1993.

“Amounts of rainfall have recovered substantially, and it was a surprise that the increase in greenhouse gases appears to have been the dominant factor,” Professor Rowan Sutton, director of climate research at the University of Reading’s National Centre for Atmospheric Science, UK, told Reuters news agency.

The scientists report in Nature Climate Change that greenhouse gas (GHG) emissions accounted for three-quarters of the recovery in rainfall, rather than other possible factors such as changes in sea temperature or air pollution from acid rain. Air warmed by GHGs can hold more moisture − which releases more rain − and can also affect wind patterns.

Welcome sign

Not surprisingly, the report comes with qualifications, and no one is hailing it as anything more than a welcome sign that one part of Africa is gaining more than it is losing from global warming − for the moment, at least.

Prof Sutton, co-author of the study, stressed that the change in Sahelian rainfall was only local, and that warming is still affecting many parts of Africa through desertification, floods and rising sea levels.

“It would be naïve to conclude that this is a good thing for Africa,” he said. “And, in future, there are other effects. The rise in temperatures can be detrimental to crops.”

But whatever climate change may bring, the people of the Sahel are working for a better future.

The World Resources Institute (WRI), based in Washington DC, has researched the role that the region’s farmers are playing, and has produced a report containing practical guidance and examples of how to scale up “regreening”.

This is a restoration technique that hundreds of thousands of farmers in three Sahelian countries − Burkina Faso, Ethiopia and Niger − and in Malawi are already using to make their land more productive.

“It would be naïve to conclude that this is a good thing for Africa. In future . . . the rise in temperatures can be detrimental to crops”

Regreening uses a range of agroforestry and sustainable land management practices, and the WRI report focuses on one in particular that it says is “particularly promising”: farmer-managed natural regeneration (FMNR).

In FMNR systems, farmers protect and manage the growth of trees and shrubs that regenerate naturally in their fields from root stock or from seeds dispersed through animal manure. It can be an easy, low-cost way for farmers to increase the number of trees in the fields – and it is producing results in the Sahel.

In Burkina Faso, farmers are using water-harvesting techniques such as building stone lines and improved planting pits, known locally as zai. These help trap rainfall on crop fields, increasing average cereal yields from 400kg to around 900kg (880-1,984 lbs) per hectare.

Important food crops

One farmer in Burkina Faso said he had not needed to plant a single tree since 1979, because they grew naturally. Others said that FMNR had improved their yield from important food crops, such as millet.

In neighbouring Niger, the increased density of trees on cropland has reduced the time women spend collecting firewood from 2.5 hours each day to an average of half an hour.

Robert Winterbottom, a senior fellow with WRI’s forests programme, made a radical suggestion in a recent blog. He said that regreening the Sahel could enable people to stay at home, instead of joining the current tide of migration by refugees risking their lives to cross the Sahara and the Mediterranean to escape to Europe.

“Farmers have already demonstrated their ability to innovate and adopt practices that restore degraded land and provide a means to secure their futures,” he said.

“Perhaps citizens throughout Africa can prosper in their home countries, eliminating the need to take to the sea to pursue a better quality of life.” − Climate News Network

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Pope calls for moral campaign on climate crisis

Pope calls for moral campaign on climate crisis

Hard-hitting message from the Vatican warns of the threat global warming poses to the world’s ecosystems − and to everyone on the planet.

LONDON, 17 June, 2015 – Pope Francis has challenged climate change deniers by declaring that the destruction of the ecosystem is a moral issue that has to be tackled, or there will be grave consequences for us all.

Pointing to human activity as the main cause for the increasing concentrations of climate-warming greenhouse gases, he praises ecological movements – and, in exceptionally strong language, rounds on those who are obstructing progress in the fight against climate change.

“The attitudes that stand in the way of a solution, even among believers, range from negation of the problem to indifference, to convenient resignation or to blind faith in technical solutions,” the Pope says.

Meant for everyone

His message is contained in an encyclical, a document on Catholic teaching that is traditionally addressed to bishops. But, in this case, he says his words are aimed not only at an estimated 1.2 billion Catholics around the world − they are meant for everyone.

“Faced with the global deterioration of the environment, I want to address every person who inhabits the planet,” the Pope says.

The encyclical − entitled Laudato Si, or Be Praised, and nearly 200 pages long − is the first such document issued by the Vatican dealing specifically with the environment.

It was due to have been released tomorrow, but parts of a draft appeared early in the Italian magazine, L’Espresso − much to the annoyance of Vatican officials.

“Humanity is called to take note of the need
for changes in lifestyle and changes in methods
of production and consumption
to combat this warming”

Unlike many of his predecessors, Pope Francis has shown a desire, since he became pontiff in 2013, to enter into debate about economic and environmental matters, as well as spiritual issues.

“If we destroy Creation, Creation will destroy us – never forget that,” he told a gathering in St. Peter’s Square, Rome, earlier this year.

The Pope says in the draft of the encyclical that the poor are trapped by environmental and financial degradation, and that the world’s resources cannot continue to be looted by humankind.

“Humanity is called to take note of the need for changes in lifestyle and changes in methods of production and consumption to combat this warming, or at least the human causes that produce and accentuate it,” he says.

The impact of the Pope’s message is likely to be considerable. Although the number of church-going Catholics has dropped in Europe and many other parts of the industrialised world, the influence of the church is growing in many areas, particularly in Africa.

The encyclical is also likely to give added momentum to the need for a climate agreement at the UN Conference on Climate Change in Paris at the end of the year.

John Grim, who lectures in world religions at the School of Forestry and Environmental Studies at Yale University in the US, says the Pope’s teachings give a significant moral voice to climate change issues.

He says: “What we have lacked in many settings is the moral voice of religious leadership informing congregations, denominations and different religions of the depth of the science and the impact on human communities of widespread climate change.”

Repeated warnings

The encyclical is likely to attract criticism from sceptics seeking to deny that there is any such thing as climate change, and who in the past have accused the Pope of straying into areas he knows little about.

Conservatives in the US have branded the Pope’s repeated warnings about growing inequality as the talk of a communist and a Marxist.

In September, Pope Francis is due to go to New York to address the United Nations, and will also speak to the US Congress in Washington.

Vatican officials say the pontiff will continue to speak out on issues linked to poverty and climate change. – Climate News Network

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