Tag Archives: Agriculture

Eat a plant and spare a tree

A Paraguay cattle ranch: More meat will mean fewer forests Image: Peer V via Wikimedia Commons

A Paraguay cattle ranch: More meat will mean fewer forests
Image: Peer V via Wikimedia Commons

By Alex Kirby

A less meat-intensive diet is essential for the sake of wildlife and forests and to slow climate change, says a report by UK-based researchers.

LONDON, 31 August 2014 – Say goodbye to the steaks. Forget the foie gras. Put that pork chop away (assuming you can afford any of them). UK-based scientists say eating less meat is a vital part of tackling climate change.

A study published in Nature Climate Change says that on present trends food production on its own will reach – and perhaps exceed – the global targets for total greenhouse gas emissions in 2050.

Healthier diets – defined as meaning lower meat and dairy consumption – and reduced food waste are among the solutions needed to ensure food security and avoid dangerous climate change, the study says.

More people, with more of us wanting meat-heavy Western diets, mean increasing farm yields will not meet the demands of an expected 9.6 billion humans. So we shall have to cultivate more land.

This, the authors say, will mean more deforestation, more carbon emissions and further biodiversity loss, while extra livestock will raise methane levels.

Inefficient converters

Without radical changes, they expect cropland to expand by 42% by 2050 and fertiliser use by 45% (over 2009 levels). A further tenth of the world’s pristine tropical forests would disappear by mid-century.

All this would cause GHG emissions from food production to increase by almost 80% by 2050 – roughly equal to the target GHG emissions by then for the entire global economy.

They think halving food waste and managing demand for particularly environmentally-damaging food products – mainly from animals -  “might mitigate some” GHG emissions.

“It is imperative to find ways to achieve global food security without expanding crop or pastureland,” said the lead researcher, Bojana Bajzelj, from the University of Cambridge’s department of engineering, who wrote the study with colleagues from Cambridge’s departments of geography and plant sciences and the University of Aberdeen’s Institute of Biological and Environmental Sciences.

“The average efficiency of livestock converting plant feed to meat is less than 3%, and as we eat more meat, more arable cultivation is turned over to producing feedstock for animals… Agricultural practices are not necessarily at fault here – but our choice of food is.”

Squandered resources

This measure of efficiency is based on the units used in the study, which are grams of carbon in the biomass material, plant or meat.

The team created a model that compares different scenarios for 2050, including some based on maintaining current trends.

Another examines the closing of “yield gaps”. These gaps, between crop yields from best practice farming and actual average yields, exist everywhere but are widest in developing countries – particularly in sub-Saharan Africa. The researchers advocate closing the gaps through sustainable intensification of farming.

But even then projected food demand will still demand additional land and more water and fertilisers – so the impact on emissions and biodiversity remains.

Food waste occurs at all stages in the food chain, caused in developing countries by poor storage and transport and in the north by wasteful consumption. This squanders resources, especially energy, the authors say.

“As well as encouraging sustainable agriculture, we need to re-think what we eat”

Yield gap closure alone still shows a GHG increase of just over 40% by 2050. Closing yield gaps and halving food waste shows emissions increasing by 2%. But with healthy diets added too, the model suggests that agricultural GHG levels could fall by 48% from their 2009 level.

The team says replacing diets containing too much food, especially emission-intensive meat and dairy products, with an average balanced diet avoiding excessive consumption of sugars, fats, and meat products, significantly reduces pressures on the environment even further.

It says this “average” balanced diet is “a relatively achievable goal for most. For example, the figures included two 85g portions of red meat and five eggs per week, as well as a portion of poultry a day.”

Co-author Professor Pete Smith from the University of Aberdeen said: “Unless we make some serious changes in food consumption trends, we would have to completely decarbonise the energy and industry sectors to stay within emissions budgets that avoid dangerous climate change.

“That is practically impossible – so, as well as encouraging sustainable agriculture, we need to re-think what we eat.” – Climate News Network

Waste could fertilise food cost cuts

Waste not, want not: a maize anaerobic digester Image: Alex Marshall/Clarke Energy Ltd via Wikimedia Commons
Waste not, want not: a maize anaerobic digester on a farm in the UK
Image: Alex Marshall/Clarke Energy Ltd via Wikimedia Commons

By Alex Kirby

Scientists are developing a way to squeeze the last vestiges of value from renewable energy processes by combining their waste products to produce eco-friendly fertilisers that could help slow food price rises.

LONDON, 30 August 2014 − Researchers in the UK think they may have found a way to produce fertilisers that should cut farmers’ costs and at the same time boost some types of renewable energy.

Their scheme, which involves using waste material from anaerobic digesters and ash from burnt biomass, would also cut fossil fuel use and save natural resources.

The team, based at the Environment Centre at the University of Lancaster, says their fertiliser would help to slow the rise in food prices. And they believe it would work worldwide.

The three-year project has received more than £850,000 (US$1.4 m) in funding from the UK’s Natural Environment Research Council. Research, due to start this year, will take place in labs at the university and in field trials.

The project, which includes several partners working with the university, aims to produce a sustainable, environmentally-friendlier source of soil conditioner and crop fertiliser.

Potential

It builds on research originally conducted by one of the partners, Stopford Energy and Environment Ltd consultancy, which investigated using a mixture of digestates − the waste left over after material has been through an anaerobic digester − and ash, from burnt biomass, as an alternative to existing fertilisers.

Most fertilisers now in use, such as phosphorous-based and nitrate-based products, are made using energy-intensive methods that involve the consumption of oil and gas.

Phosphate-based fertiliser relies as well on the mining of phosphate, a finite and unsustainable resource, and on a production process using various toxic chemicals.

There are already projects in several countries − including the UK − that use waste from digesters to make fertiliser.

But Professor Kirk Semple, of the Lancaster Environment Centre, who leads the project, said: “It is the mixing of anaerobic digestate with biomass ash that is important. . . This would reduce pressure on natural resources and develop a new market for problematic by-products of the bio-energy industry.

“Although the project is based here in the UK, we believe there is exciting potential to produce a sustainable alternative to existing fertiliser use across the globe.”

Nutrients

A successful digestate-ash fertiliser would reduce costs and provide additional income to biomass and anaerobic digestion operators. The Lancaster team says this could make these forms of renewable energy − which could meet more than 15% of UK energy demand by 2020 − more appealing to investors, as at the moment ash has to be expensively dumped in landfills.

They say it could help to improve food security and reduce costs to farmers as production of the new fertiliser would not be linked to the global price of oil and gas.

Previous studies by Stopford show that biomass ash and digestate can be useful nutrient sources for crops in conditions which lack them.

Professor Semple told the Climate News Network that he and his colleagues were working to ensure that the new fertiliser was entirely safe. He said: “Part of the grant will be used to chemically analyse the materials, individually and together, for metals and potentially other chemicals.”

He says commercial-scale production of a successful digestate-ash fertiliser “is some way off”. But he adds: “This project offers the first detailed interrogation of this type of soil amendment. If successful, we would then look to develop this for the commercial sector.” − Climate News Network

Food security faces growing pest advance

Root knot nematode (Meloidogyne incognita) on a tomato plant Image: Courtesy of CABI

Root knot nematode (Meloidogyne incognita) on a tomato plant
Image: Courtesy of CABI

By Tim Radford

A world with more people will see more competition for food. Many of our competitors may not be human, because natural pests are spreading far and wide.

LONDON, 29 August 2014 - Coming soon to a farm near you: just about every possible type of pest that could take advantage of the ripening harvest in the nearby fields.

By 2050, according to new research in the journal Global Ecology and Biogeography, those opportunistic viruses, bacteria, fungi, blights, mildews, rusts, beetles, nematodes, flies, mites, spiders and caterpillars that farmers call pests will have saturated the world.

Wherever they can make a living, they will. None of this bodes well for food security in a world of nine billion people and increasingly rapid climate change.

Dan Bebber of the University of Exeter, UK,  and colleagues decided to look at the state of pest populations worldwide. They combed the literature to check the present status of 1,901 pests and pathogens and examined historical records of another 424 species. This research included the records made since 1822 by the agricultural development organization CABI.

Crop pests often emerge in one location, evolve and spread. That notorious potato pest the Colorado beetle, for instance, was first identified in the Rocky Mountains of the US in 1824.

Rising trend

The scientists reasoned that climate change and international traffic made transmission of pests across oceans and other natural barriers increasingly probable, and tried to arrive at a rate of spread.

They found that more than one in 10 of all pest types can already be found in half of the countries that grow the host plants on which these pests depend. Most countries reported around one fifth of the pests that could theoretically make their home there.

Australia, China, France, India, Italy, the UK and the USA already had more than half of all the pests that could flourish in those countries. The pests that attack those tropical staples yams and cassava can be found in one third of the countries that grow those crops.

This trend towards saturation has increased steadily since the 1950s. So if the trend continues at the rate it has done during the late 20th century, then by 2050 farmers in western Europe and the US, and Japan, India and China will face saturation point.

They will be confronted with potential attack from just about all the pests that, depending on the local climate and conditions, their maize, rice, bananas, potatoes, soybeans and other crops could support.

Early warning

“If crop pests continue to spread at current rates, many of the world’s biggest crop-producing nations will be inundated by the middle of the century, posing a grave threat to global food security,” Dr Bebber said.

Three kinds of tropical root knot nematode produce larvae that infect the roots of thousands of different plant species. A fungus called Blumeria graminis causes powdery mildew on wheat and other grains; and a virus called Citrus tristeza, first identified by growers in Spain and Portugal in the 1930s, had by 2000 reached 105 out of the 145 countries that grow oranges, lemons, limes and grapefruit.

Predictions such as these are intended to be self-defeating: they present a warning of what might happen if no steps are taken.

“By unlocking the potential to understand the distribution of crop pests and diseases, we’re moving one step closer to protecting our ability to feed a growing global population,” said Timothy Holmes, of CABI’s Plantwise knowledge bank, one of the authors. “The hope is to turn data into positive action.” - Climate News Network

Elections sideline São Paulo drought crisis

Drought has now hit dams on rivers such as the Paranapanema Image: José Reynaldo da Fonseca via Wikimedia Commons
Past prime: drought has now hit dams on rivers such as the Paranapanema
Image: José Reynaldo da Fonseca via Wikimedia Commons

By Jan Rocha

As South America’s biggest city suffers its worst drought in over a century, São Paulo state politicians are putting re-election prospects ahead of the need to introduce measures to address a desperate situation for millions of people.

SÃO PAULO, 25 August, 2014 − Outside the semi-arid area of the north-east, Brazilians have never had to worry about conserving water. Year in, year out, the summer has always brought rain.

But that has changed dramatically. São Paulo, the biggest metropolis in South America, with a population of almost 20 million, is now in the grip of its worst drought in more than a century − a water crisis of such proportions that reports on the daily level of the main reservoir arefollowed as closely as the football results.

The lack of rain is also affecting the dams that produce most of Brazil’s energy, highlighting the urgent need to diversify power sources.

And yet the state governor, wary of the effects on his prospects in forthcoming elections, has refused to introduce measures to ration, or even conserve, water.

Mighty rivers

Brazil is blessed not only with the mighty Amazon and all its huge tributaries, but also with dozens of other lengthy, broad rivers − once the highways for trade and slaving expeditions, but now providing waterways for cargo, power for dams, and water for reservoirs.It has at least 12% of the world’s fresh water supply.

But five of the principal rivers – the Tiete, Grande, Piracicaba, Mogi-Guaçu and Paraiba do Sul − that cross or border São Paulo, Brazil’s wealthiest state, have less than 30% of the water they should have at this time of year, according to data from the regional Hydrographic Basin Committee and from the National Electric System Operator (ONS).

Other major water sources – such as the Paraná, South America’s second biggest river, and the Paranapanema − are also suffering from the long dry period. The ruins of towns flooded for dam reservoirs have reappeared, fishermen’s boats are beached because the fish have disappeared, and navigation is at a standstill.

The transport of grain and other cargos to the port of Santos, via the river network, had to be suspended after the water level fell by up to eight metres. The equivalent of 10,000 lorryloads of cargo have been transferred by road so far.

Many industries have suspended their activities because of lack of water, and the drought has resulted in the loss of part of the coffee, sugar cane and wheat crops in one of Brazil’s most important agricultural states.

The hydrological period lasting from October 2013 to March 2014 was the driest for 123 years, according to the Agronomic Institute of Campinas, the oldest institute of its kind in Latin America .

Lowest volume

The federal government’s energy research company, EPE, found that in the first three months of 2014 the volume of rain was the third lowest since the 1930s.

It was the third consecutive year of reduction for the reservoirs of the hydroelectric dams that make up the South-east/Centre-West System, where many of Brazil’s biggest cities are located. From 88% in 2011, the volume of water in them had fallen to 38% by April 2014 – the month in which the dry season begins in this region.

By mid-August, the reservoirs of the Cantareira system, which supplies the water for almost 8.5 million of São Paulo’s inhabitants, had fallen to just 13.5% of capacity.

Yet the state government of São Paulo has so far refused even to admit that there is a crisis. The problem is the October elections, when Governor Geraldo Alkmim is running for re-election. Like most politicians, he does not want to be associated with a crisis. The word “rationing” is taboo.

Instead, unofficial rationing – what might be called rationing by stealth – is in operation. At night, the São Paulo Water Company, Sabesp, is reducing the pressure in the water system by 75%, leaving residents in higher areas of the city with dry taps.

Over 80% of the country’s energy comes from hydroelectric power, and dozens more giant dams are under construction or planned, mostly in the Amazon basin. The government has been strangely reluctant to invest in, or even encourage, other sources of abundant renewable energy, such as wind, solar and biomass.

The over-reliance on hydropower has already led to a distortion. The back-up system of thermo-electric plants, run on gas and diesel, and designed for emergencies, has had to increase production from 8% in 2012 to cover 25% of energy demand this year − thus contributing to higher carbon emissions.

Politics have also interfered with the special crisis committee set up to monitor the drought situation, with representatives from local and federal agencies unable to agree on what to do.

The Sao Paulo energy company, CESP, unilaterally decided this month to reduce the volume of water released from the shared Jaguari reservoir to the neighbouring state of Rio de Janeiro for electricity generation, in order to keep more for its own water needs.

Dangerous precedent

For Marcio Zimmerman, executive secretary of the Ministry of Mines and Energy, CESP’s action creates a dangerous precedent. “There will be chaos if everyone decides to rebel against the ONS,” he said.

The realisation that climate change is already leading to major changes in weather patterns has sounded alarm bells among the business community about the need to diversify energy sources and conserve water.

Early this month, at a seminar organised by the Brazilian Business Council for Sustainable Development, the chief executives of more than 20 top companies drew up a list of 22 crisis-related proposals to be put to the presidential candidates in October’s election.

Newspaper editorials are now urging the politicians to take their heads out of the sand and involve the population in a serious discussion on the crisis and its effects on the water supply, energy generation, and food production .

The Rio newspaper O Globo declared: “They belittle the potential for efficiency available in a society accustomed to waste. When they act, it might be too late.” – Climate News Network

Climate and economy fan flames in Spain

A swathe of forest destroyed by wildfire in northern Spain Image: DM Molina Terrén via Wikimedia Commons
Burn scars: a swathe of forest destroyed by wildfire in northern Spain
Image: DM Molina Terrén via Wikimedia Commons

By Tim Radford

The combined forces of climate, economic and social change are leaving Spain increasingly exposed to the damaging and costly effects of wildfires.

LONDON, 21 August, 2014 – Climate change is gradually turning Spain into a fire zone – but it’s also the change in the economic climate that is inflaming the situation.

A research group reports in the journal Environmental Science and Policy that a mix of factors is behind the rise in both the numbers of forest fires and the areas of land scorched over the last 40 years.

Vanesa Moreno, a researcher in the geography department at the University of Alcalá in Madrid, and colleagues studied the pattern of fires in Spain from 1968 to 2010.

Natural outbreaks

Although Spain, like much of southern Europe, is expected to become more arid with global warming, and although some Mediterranean vegetation is adapted to − and even benefits from − natural fire outbreaks, the picture is not a simple one.

In the moister Atlantic north-west of the country, there are two fire seasons − at the end of winter, and in the summer. In the Mediterranean region, fires are more frequent in the long, hot summer.

Climate change, with more prolonged droughts and rising temperatures, is certainly a driving force, but another factor has been the way the land is now used.

Increasingly, agriculture has intensified and old customs have withered away. Traditional shepherding practices once relied on using fire to keep pastures clear, and, as these practices were abandoned, the risk of accidental scrub and bush and forest fire fell.

But at the same time, like everywhere else in the world, people began to abandon the rural landscape and move to the cities, which in turn means more uncontrolled vegetation growth, more tinder and dried leaves to ignite, and a greater risk of forest fire once more.

Additionally, there have been new reforestation policies, and new plantations for pulp and paper, so that there is more forest to catch fire.

Woodland now covers 37% of the 493,000 square kilometres under study, and the animal population per sq km has fallen from 45 sheep, goats or cattle to a mere 12. So social change, too is fuelling the fire hazard.

Alarming number

Across the Atlantic, from Alaska to California, wildfires are on the increase. Europe, too, has this summer been hit by an alarming number of fires. But knowledge is power, and the Spanish know what to expect.

Moreno says: “Management has evolved and become more effective through the acquisition of fire suppression resources, professional training, research, the introduction of technologies and prevention − something that has got a lot of attention in recent years.” says Moreno.

But that does not mean the fire situation is under control. “The occurrence of several fires at the same time means that resources and personnel have to be split, and extinguishing fires takes more time,” Moreno says.

“In this regard, the economic crisis has caused the workforce to be cut, which could reduce fire extinguishing ability.” – Climate News Network

Climate change heralds end of civilisations

Arid land in the former Fertile Crescent area of south-west Syria Image; Simone Riehl/Tübingen University
Arid landscape in the former ‘Fertile Crescent’ area of south-west Syria
Image; Simone Riehl/Tübingen University

By Paul Brown

New research supports the growing body of evidence that many past civilisations have collapsed because of climate change. So is history repeating itself?

LONDON, 13 August, 2014 –  Scientists looking at what is known as the “Fertile Crescent” of ancient Mesopotamia have found new evidence that drought caused by climate change brings an end to civilisations.

It is the latest study that confirms the threat posed to present civilisations in Africa, Asia and parts of the United States by changes in rainfall pattern that could lead to the abandonment of once-fertile areas − and the cities that once were fed by them.

The focus of research by a team from Tübingen University, Germany, is the area currently part of Iraq and the Persian Gulf where the development of ancient agriculture led to the rise of large cities.

Evidence from grain samples up to 12,000 years old shows that while the weather was good, the soil fertile and the irrigation system well managed, civilisation grew and prospered. When the climate changed and rainfall became intermittent, agriculture collapsed and the cities were abandoned.

Analysed grains

Dr Simone Riehl, of the Institute for Archaeological Sciences and the Senckenberg Center for Human Evolution and Palaeoenvironment at Tübingen University, analysed grains of barley up to 12,000 years old from 33 locations across the Fertile Crescent to find out if they had had enough water while growing and ripening.

The 1,037 ancient samples were between 12,000 and 2,500 years old. They were compared with modern samples from 13 locations in the former Fertile Crescent.

Dr. Riehl and her team measured the grains’ content of two stable carbon isotopes.

When barley grass gets insufficient water while growing, the proportion of heavier carbon isotopes deposited in its cells will be higher than normal. The two isotopes 12C and 13C remain stable for thousands of years and can be measured precisely – giving Riehl and her colleagues reliable information on the availability of water while the plants were growing.

They found that many settlements were affected by drought linked to major climate fluctuations. “Geographic factors and technologies introduced by humans played a big role and influenced societies’ options for development, as well as their particular ways of dealing with drought,” Riehl says.

Her findings indicate that harvests in coastal regions of the northern Levant, at the eastern end of the Mediterranean Sea, were little affected by drought. But further inland, drought led to the need for irrigation or, in extreme cases, abandonment of the settlement.

The findings give archaeologists clues as to how early agricultural societies dealt with climate fluctuations and differing local environments. “They can also help evaluate current conditions in regions with a high risk of crop failures,” Riehl adds.

The study is part of a project, backed by the German Research Foundation, looking into the conditions under which Ancient Near Eastern societies rose and fell.

Scientists carrying out similar research in the Indus Valley, in present Pakistan and north-west India, home to the Harappan Civilisation, also believe that drought was the cause of the civilisation’s demise.

It was characterised by large, well-planned cities with advanced municipal sanitation systems and a script that has never been deciphered. But the Harappans seemed to slowly lose their urban cohesion, and their cities were gradually abandoned.

Cities abandoned

According to an article in Nature in March, a 200-year drought, caused by the failure of the monsoon, led to the abandonment of the cities and the end of the civilisation.

Across the Atlantic, another puzzle was the loss of the Mayan cities and culture in Central America. This was a people that had the time, money and manpower to build massive temples and cities for a population estimated at 13 million.

Many theories have been put forward as to why, over a period of about 200 years from 750 to 950AD, the Mayans abandoned their way of life. Research on the subject by Sigma Xi, The Scientific Research Society, says that a series of droughts caused by local climate change was the cause.

With the latest report of the Intergovernmental Panel on Climate Change predicting a faltering of the monsoon that is vital for the Indian sub-continent’s ability to feed itself, it seems as though history could repeat itself. Certainly, some people in India believe it could happen unless action to curb climate change is taken.

Environmental refugees in Africa are also seen as victims of changing weather patterns, and California is suffering a three-year drought that is badly affecting water supplies in this most prosperous of American states. – Climate News Network

New rules could block biofuel’s alien invaders

The invasive giant reed (Arundo donax) has been approved in the US as a biofuel crop Image: H Zell via Wikimedia Commons
The US approved the invasive giant reed (Arundo donax) as a biofuel crop
Image: H Zell via Wikimedia Commons

By Alex Kirby

Producing biofuel from plants can help to reduce fossil fuel use and climate change emissions, but scientists warn of risks that some species may become unwelcome and damaging invaders.

LONDON, 10 August, 2014 − Researchers in the US have warned those anxious to cut greenhouse emissions to make quite sure that the cure they choose will not turn out worse than the disease.

They have developed a tool that should help to avoid the danger that efforts to address climate change could allow invasive plant species to spread where they are not wanted.

Making fuel from plants avoids using fossil fuels − although it does use land that could otherwise grow crops. But scientists are concerned that plants grown for their energy could damage their new environment.

If a plant grown as a biofuel crop is approved solely on the basis of reducing greenhouse gas emissions, the scientists from the University of Illinois warn that its potential as the next invasive species may not be discovered until it’s too late. So they have drawn up a set of regulatory definitions and provisions.

White list

They also assessed 120 potential bioenergy feedstock taxa (biological classifications of related organisms) and came up with a “white list” of 49 low-risk biofuel plants − 24 native and 25 non-native − from which growers can choose.

Lauren Quinn, an invasive plant ecologist at the university’s Energy Biosciences Institute, and her colleagues set out to create a list of low-risk biofuel crops that can be safely grown for conversion to ethanol. But in the process of doing that, they recognised that regulations were needed to instill checks and balances in the system.

“There are not a lot of existing regulations that would prevent the planting of potentially invasive species at the state or federal levels,” Dr Quinn says.

In approving new biofuel products, she says, the US Environmental Protection Agency (EPA) does not formally consider invasiveness at all – just greenhouse gas emissions related to their production.

“Last summer, the EPA approved two
known invaders . . . despite public criticism”

The report’s co-author, A. Bryan Endres, professor of agricultural law at the university, says: “Last summer, the EPA approved two known invaders, Arundo donax [giant reed] and Pennisetum purpurem [napier grass], despite public criticism.”

The researchers say there is no clear and agreed scientific definition of what “invasive” means, although the UN Convention on Biological Diversity has made a brave attempt, while also broadening the category. It says: “Invasive alien species have devastating impacts on native biota, causing decline or even extinctions of native species, and negatively affecting ecosystems.”

Dr Quinn says: “Our definition of invasive is ‘a population exhibiting a net negative impact or harm to the target ecosystem’ . . . We want to establish guidelines that will be simple for regulators, and informed by the ecological literature and our own knowledge.

“We also need to recognise that some native plants can become weedy or invasive. It’s complicated, and requires some understanding of the biology of these plants.

High risk

“Some of the biofeedstocks currently being examined by the EPA for approval, like pennycress, have a high risk for invasion. Others have vague names such as jatropha, with no species name, which is problematic.

“For example, there are three main Miscanthus species, but only sterile hybrid Miscanthus giganteus types are considered low risk. However, the EPA has approved “Miscanthus” as a feedstock, without specifying a species or genotype.

“That’s fine for the low-risk sterile types, but could mean higher-risk fertile types could be approved without additional oversight.”

Dr Quinn thinks the team’s list of  low-risk feedstock plants will serve to clear up the confusion about plant names. It was developed using an existing weed risk assessment protocol, which includes an extensive list of 49 questions that must be asked about a particular species − based on its biology, ecology, and its history of being invasive in other parts of the world.

Although a plant may be native to a part of the US, it could be considered invasive if it is grown in a different region, Dr Quinn says. “For example, Panicum virgatum is the variety of switchgrass that is low risk everywhere except for the three coastal states of Washington, Oregon and California.

“But future genotypes that may be bred with more invasive characteristics, such as rapid growth or prolific seed production, may have higher risk.” − Climate News Network

Warming threatens to cut crop yields

Food for thought: a heap of maize harvested in Vietnam Image: Bùi Thụy Đào Nguyên via Wikimedia Commons
Food for thought: a heap of newly-harvested maize in Vietnam
Image: Bùi Thụy Đào Nguyên via Wikimedia Commons

By Kieran Cooke

The odds on food production being unable to meet the needs of an expanding population are hard to predict, but a new study shows that the risk increases dramatically when man-made climate change is factored in.

LONDON, 2 August, 2014 − Projecting the impact of climate change on global food production is no easy task. A warming climate might result in better crop yields in one region, but cause drought and crop failure in another.

A new US study, published in the journal Environmental Letters, assesses the odds of a major slowdown in global food production over the next 20 years.

Overall, the study’s authors say, the likelihood of a sharp drop in yields of crops vital to food supply, such as wheat and maize, is “not very high” − but global warming does markedly increase the chance of such events happening. The risk to global food supplies is about 20 times greater when man-made climate change is taken into account.

“Climate change has substantially increased the prospect that crop production will fail to keep up with rising demand in the next 20 years,” says Claudia Tebaldi, a research scientist at the National Center for Atmospheric Research and a co-author of the study.

Climate trends

Tebaldi, together with David Lobell, an associate director of the Center on Food Security and the Environment at California’s Stanford University, used computer models of global climate trends, together with data on weather patterns and crops, to calculate the odds of a major downturn in food supplies.

“I’m often asked whether climate change will threaten food supply, as if it’s a simple yes or no answer,” Lobell says.

“The truth is that, over a period of 10 or 20 years, it depends largely on how fast the Earth warms, and we can’t predict the pace of warming very precisely. So the best we can do is try to determine the odds.”

Yields of crops such as maize and wheat have typically increased by between one and two per cent a year over recent decades. This trend, says the study, needs to be maintained to cope with population growth, greater per capita food consumption, and the increased use of crops for biofuels.

The authors of the study – which was funded by the US government’s National Science Foundation and the US Department of Energy − found that under what they term natural climate shifts, the odds on that trend slowing up to 2030 were only 1 in 200.

Global food supplies

However, when human-induced global warming is taken into account, the odds shorten to one in 10 for a slowing in yields of maize and one in 20 for wheat production. Such cutbacks, says the study, would have a major impact on global food supplies at a time when demand is growing sharply.

Tebaldi and Lobell say an increase of 1˚C in temperature is capable of slowing maize yields by 7% and wheat yields by 6%, although there are regional variations to these figures.

The study says a slowdown in yields of maize and wheat could, in theory, be offset by shifting planting to cooler regions, but there is little sign that such shifts are happening – at least not quickly enough to take account of warmer temperatures.

“We can’t predict whether a major slowdown in crop growth will actually happen, and the odds are still fairly low,” says Tebaldi.

“But climate change has increased the odds to the point that organisations concerned with food security or global stability need to be aware of this risk.” − Climate News Network

New seeds of hope for Nepal’s farmers

Growing concern: in Nepal, 50% of arable land is planted with rice Image: Sigismund von Dobschütz via Wikimedia Commons
Growing concern: in Nepal, 50% of arable land is planted with rice
Image: Sigismund von Dobschütz via Wikimedia Commons

By Om Astha Rai

Climate-resilient varieties of rice could help to protect crop yields from the ravages of droughts and floods caused by the increasingly erratic weather patterns in South Asia.

KATHMANDU, 30 July, 2014 − Farmers badly affected by changing weather patterns in South Asia now have the opportunity to improve food security by planting new varieties of rice capable of withstanding the impact of both severe droughts and floods.

This is particularly good news for countries such as Nepal, where around 65% of its more than 26 million people are involved in agriculture. Rice is the country’s most important crop, planted on more than 50% of its arable land.

And it comes at a time when new research using satellite imaging has highlighted the growing need to change agricultural practices in South Asia as higher average temperatures cause the reduction of crop yields on the Indo-Gangetic plain.

Scientists say the new seeds, developed by the International Rice Research Institute in the Philippines and approved by the Nepal Agricultural Research Council (NARC), are vital in order to deal with changing weather patterns − in particular, the increasingly erratic behaviour of the all-important South Asia monsoon.

“These new varieties can really change the future of the country’s farmers,” says Dr Dil Bahadur Gurung, NARC’s executive director. “The new rice can, in most cases, beat the effects of droughts and floods.

Reduce impact

“All these varieties have been tested in Nepal’s soil and climate over and over again. If all the country’s farmers replace their traditional varieties with these new ones, the impact of climate change on our agriculture could be reduced considerably.”

Local scientists say the timing of the South Asia monsoon − the only source of irrigation for the majority of Nepali farmers − is changing.

“Each year, we see the monsoon arriving later,” says Mani Ratna Shakya, a leading meteorologist in Nepal. “The duration of the monsoon is also getting shorter as each year passes.”

According to Nepal’s Meteorological Forecasting Division, the monsoon − which usually arrives in Nepal during the first week in June − came 10 days late this year.

Droughts are becoming more frequent. This year, the monsoon is generally judged to be very weak, leaving a vast area of arable land parched, particularly in western parts of Nepal. And often, when the rains eventually do arrive, they are torrential, causing flash floods.

So far, NARC has approved six drought-tolerant varieties of rice, under the name Sukkha − meaning dry.

“Ordinary rice varieties dry out and die in droughts,” says Hari Krishna Uprety, a paddy expert at NARC. “The new seeds survive droughts even in the early stage of growth. And uncertainty about the onset of monsoon has made these varieties even more important.”

Hari Krishna Uprety, NARC paddy expert, with new rice seed varieties Image: Om Astha Rai
Hari Krishna Uprety, NARC paddy expert,
with the new rice seed varieties
Image: Om Astha Rai

The new varieties still need water, of course, but they become more drought tolerant by being able to store energy during the early stages of their growth.

Two rice varieties capable of surviving flood conditions for up to two weeks have also been approved by NARC.

Erratic climate

Although the experts are backing the introduction of the new seeds in order to combat an increasingly erratic climate, persuading farmers to change their cultivation methods is a difficult task.

Farmers are often reluctant to replace traditional rice varieties, which in Nepal tend to be specific to each part of the country, depending on soil conditions, elevation, and other factors.

The new seeds are no more expensive than the traditional ones, and farmers even get a 30% discount on seeds approved by NARC, but a factor that could hamper uptake is that distribution is through the National Seed Company, which is not yet reaching out to farmers in every village.

But scientists warn that the new varieties must be planted – not only to combat changes in climate, but also to feed growing populations. – Climate News Network

• Om Astha Rai is a reporter with Nepalese national newspaper, Republica Daily.

Rising heat hits Indian wheat crop

 

Feeling the heat: crop harvests in India yielding less Image: Yann via Wikimedia Commons
Feeling the heat: the yield from wheat harvests in India is falling
Image: Yann via Wikimedia Commons

By Alex Kirby

Satellite imaging highlights the growing need to change agricultural practices in South Asia as higher average temperatures cause the reduction of crop yields on the Indo-Gangetic plain.

LONDON, 28 July, 2014 − Researchers in the UK have established a link between changing climate and agriculture that could have significant consequences for food supplies in South Asia.

They have found evidence of a relationship between rising average temperatures in India and reduced wheat production, which was increasing until about a decade ago but has now stopped.

The researchers, Dr John Duncan, Dr Jadu Dash and Professor Pete Atkinson, all geographers at the University of Southampton, say an intensification is predicted for the recent increases in warmth in India’s main wheat belt that are damaging crop yields.

The greatest impact that the hotter environment has on wheat, they say, comes from a rise in night-time temperatures.

Vulnerability

Dr Dash said: “Our findings highlight the vulnerability of India’s wheat production system to temperature rise. We are sounding an early warning to the problem, which could have serious implications in the future and so needs further investigation.”

The team is the first to use satellite imagery to establish the link between warming and crop yields. The images were taken at weekly intervals, from 2002 to 2007, of the wheat-growing seasons to measure the “vegetation greenness” − an indicator of crop yield.

The imagery, of the north-west Indo-Gangetic plain, was taken at such a high resolution that it was able to capture variations in local agricultural practices. The plains stretch over much of northern and eastern India, and into parts of Pakistan, Nepal and Bangladesh.

The data was then compared with climate and temperature information for the area to examine the effect on growth and development of the crop.

The study, published in the journal Global Change Biology, found that warmer temperatures reduced crop yield. Greater warmth during the reproductive and ripening periods, in particular, had “a significant negative impact on productivity”. But it was the warmer nights that did the greatest harm.

In some parts of the Indian wheat belt, growers have been advancing their growing season to make sure that the most sensitive point of the crop growth cycle falls within a cooler period. But in the long term, the researchers say, this will not help, because of the high average temperature rises predicted.

Dr Dash said farmers would have to think seriously about changing to more heat-tolerant wheat varieties. “Currently in India, 213 million people are food insecure and over 100 million are reliant on the national food welfare system, which uses huge quantities of wheat,” he said.

Regular data

“We hope that soon we will be able to examine agricultural practices in even greater detail, with the launch of the European Space Agency’s Sentinel satellites, which will provide regular data at even higher spatial resolution.”

In 2012, India was the world’s second largest wheat producer, with 94.9 million tonnes. It was self-sufficient and able to sell some wheat overseas, although the government has now limited exports.

India’s production was exceeded only by China’s. But China is building up its reserves of wheat, and is now widely seen as working more energetically than many developing countries for an ambitious global climate change agreement.

Dr Dash told the Climate News Network: “Ten years ago, India’s yield of wheat was increasing. Today, it’s stagnant − and the predictions are that, by 2050, average temperatures will be 5% higher than they are now. This is a wake-up call for the whole of South Asia.” − Climate News Network