Extreme weather puts Africa’s food security at risk

Extreme weather puts Africa's food security at risk

A British government scientific panel says increasingly frequent heat waves, droughts and other extreme weather threaten more – and more severe – global food crises.

LONDON, 15 August, 2015 – Developing countries in sub-Saharan Africa which depend heavily on food imports will be worst hit by the increasingly extreme global weather, a report says, with the Middle East and North Africa also threatened, in this case by social unrest.

In contrast, the authors say the impact on the world’s biggest economies is likely to be muted. But they think a serious crisis could occur as soon as 2016, with repercussions in many countries.

They write: We present evidence that the global food system is vulnerable to production shocks caused by extreme weather, and that this risk is growing…preliminary analysis of limited existing data suggests that the risk of a 1-in-100 year production shock is likely to increase to 1-in-30 or more by 2040.”

The report was jointly commissioned by the UKs Foreign and Commonwealth Office and its Government Science and Innovation Network, with a foreword by the countrys former chief government scientist, Sir David King.

He writes: We know that the climate is changing and weather records are being broken all the time…The food system we increasingly rely on is a global enterprise. Up to now its been pretty robust and extreme weather has had limited impact on a global scale. But…the risks are serious and should be a cause for concern…

Likely scenarios

We should be looking carefully at even very low probability situations, and the likelihood of the scenarios suggested in this report are far too significant to ignore.”

The report says the UN’s Food and Agriculture Organisation estimates that by 2050 global food demand will be 60% above todays, with per capita demand also growing, and more meat-eating.

In 2007/8 a small weather-related production shock, coupled with historically low stock levels, led to rapid food price inflation in the main internationally traded grains, as measured by the FAO Food Price Index.

Prices rose by over 100%. A similar price spike occurred in 2010/11, partly driven by the weather in eastern Europe and Russia.

In 2012, the worst drought to hit the American Midwest for half a century triggered comparable spikes in international maize and soya prices. There is good evidence, the report says, that extreme weather events, from intense storms to droughts and heat waves, are increasing significantly.

Food production of the globally most important commodity crops (maize, soya, wheat and rice) comes from a small number of major producing countries.

Multiple failure

Simultaneous extreme weather events in two or more of these regions – creating a multiple bread basket failure – would represent a serious production shock. There is an urgent need to understand the driving dynamics of linked problems such as the El Niño effect – which may be becoming more extreme – the report says.

By examining production shocks in the recent past, the authors devised what they call a plausible worst case scenario” – a simultaneous drought affecting maize and soya production, and another which damages wheat and rice harvests.

More topically, they also describe what they say is a plausible worst case scenario for 2016. This involves a complex sequence, starting with a disappointing 2015 Indian monsoon, the loss of much of 2016s Black Sea winter wheat crop, and then Russian and Ukrainian export bans.

International wheat prices rise fast, prompting similar measures in south and central Asia and Argentina, and repercussions as far afield as China, Iran, Saudi Arabia and Morocco.

In late spring a persistent drought starts in North America, affecting soya and maize forecasts and prices. Then a heatwave and drought hit the European wheat crop, leading to further rises across all cereals.

Panicked markets

In early summer a second failure of the Indian monsoon unleashes panic in the rice market, where Asian households have been steadily hoarding. Myanmar, Sri Lanka, Egypt and Nepal impose export restrictions.

Major importers such as Nigeria, Malaysia and the Philippines place orders far above normal levels in a bid to calm domestic markets. The scenario ends with still more countries
– Vietnam, Cambodia and Indonesia – imposing export bans.

One of the reports recommendations is that agriculture should adapt to a changing climate.

That, it says, means productivity must be increased by reversing declines in yield growth and closing the gap between actual and attainable yields in the developing world, while also reducing agricultures environmental impact, including the depletion of fresh water and the increase in greenhouse gas emissions.

However, it says, given the increasing risk of extreme weather, this cannot come at the expense of production resilience. – Climate News Network

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Added gene can make rice more climate-friendly

Added gene can make rice more climate-friendly

Scientists discover a way to boost production of the grain that billions rely on for food – and reduce its damaging emissions of methane.

LONDON, 14 August, 2015 – An international team of scientists has found a way to make rice more productive, more nutritious and less of a greenhouse gas producer – simply by adding just one gene from the cereal, barley.

The single gene SUSIBA 2 – the acronym stands for sugar signalling in barley – makes all the difference. And the importance of the breakthrough is that rice feeds half the world – but, as it grows, is one of the great sources of the greenhouse gas, methane.

The world’s rice paddy fields release up to 100 million tonnes each year of methane − possibly 17% of the global total.

And although methane emissions are small compared with carbon dioxide, each molecule of methane is far more potent a global warmer. The gas is 34 times more potent than CO2 over a century, but 84 times more so over a much shorter timespan – just 20 years.

Ideal conditions

The conditions ideal for rice – warm and waterlogged, and mud, rich with nutrients − are also ideal for the generation of methane.

The scientists from China, Sweden and the US report in Nature journal that they calculated that if they could do something to encourage the conversion of sugars to starches in the rice plant, there would be more productivity in the stalk and ears, and less around the roots, where the methane-generating bacteria flourish.

In their words, this would “generate a high starch, low methane emission variety”.

They used transcription factor technology – a form of genetic modification that could soon also deliver better drought tolerance in some important crop plants – and began tests at the Fujian Academy of Agricultural Sciences in Fuzhou, China, in 2012 and 2013. Transcription factors bind to genes and turn them on or off.

“As the world’s population grows, so will rice production. And as the Earth warms, so will rice paddies, resulting in even more methane emissions”

Earlier experiments in Sweden had helped the team understand how to manage the transcription factors so they could just about dictate which parts of the plant absorbed more of the carbon taken from the atmosphere by photosynthesis.

The result was a rice variety that yielded more starch, so that it delivered more energy per spoonful for a hungry household, or that could be converted to more biofuel during times of surplus.

Japanese scientists, too, have been looking for ways to get all the value they can out of one of the world’s most vital crops. But the other important outcome, the researchers say, was a near-elimination of methane production from around the roots.

The next step is to look at what happens in the paddy fields, and try to understand what is going on and what the change could mean for methane-generating bacteria.

Test variety

The scientists also dried the whole plant once it had ripened to examine what had occurred, and to compare it with control varieties in the same fields. They found that grains of the test variety contained almost 87% starch, compared with 77% in the control sample.

The research still has a long way to go, but given that global population could sometime this century hit or even surpass 10 billion, and given that the land available for farming cannot expand, there is pressure to increase yields per field.

Ominously, research so far suggests that global warming – and the accompanying greater extremes of heat in the growing season – could reduce yields. So plant scientists must make the most of any advances in the understanding of the biology of growth.

“The need to increase starch content and to lower methane emissions from rice production is widely recognised, but the ability to do both simultaneously has eluded researchers,” says Christer Jansson, a co-author of the report, and director of plant sciences at the US Pacific Northwest National Laboratory.

“As the world’s population grows, so will rice production. And as the Earth warms, so will rice paddies, resulting in even more methane emissions. It’s an issue that must be addressed.” – Climate News Network

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Mangroves hold key to Indonesia’s emissions cuts

Mangroves hold key to Indonesia’s emissions cuts

New study says Indonesia could go a quarter of the way to reaching its 2020 target for carbon emissions reduction by ending the destruction of its vital mangrove forests.

LONDON, 27 July, 2015 – Indonesia, one of the world’s largest carbon emitters, would take a major step towards losing that tag by protecting its massive mangrove forests, according to new research.

The mangroves, which store prodigious quantities of carbon, are currently disappearing fast − often destroyed to make room for aquaculture to satisfy the wants of lucrative foreign markets.

But a team from the Centre for International Forestry Research (CIFOR) and colleagues report in the journal Nature Climate Change that protecting the mangroves could take Indonesia a quarter of the way to achieving the whole of the greenhouse gas emissions cuts it plans for 2020.

Indonesia, with the longest coastline in the tropics, has more mangroves than any other country − more than 2.9 million hectares. But it also has one of the world’s fastest rates of mangrove loss.

The main threats to the forests include conversion to shrimp ponds, logging, conversion of land to agriculture or salt pans, and degradation by oil spills and pollution.

In 2013, Indonesia’s revenue from shrimp exports was close to US$1.5bn, almost 40% of the total revenue from the country’s fishery sector.

Grave threat

The researchers say the Indonesian mangroves, some of which grow to 50 metres in height, store 3.14 billion tonnes of carbon, which amounts to one-third of the carbon stored in Earth’s coastal ecosystems.

But they are under grave threat. In the last 30 years, 40% of these coastal forests have gone, and the annual rate of loss now is about 52,000 hectares, causing substantial greenhouse gas emissions.

The current rate of destruction means that 190 million tonnes of CO2-equivalent (CO2e) are emitted annually. That is 42% of the world’s annual emissions from the destruction of coastal ecosystem services − marshes, mangroves and sea grasses.

Put more graphically, Indonesia’s destruction of its mangroves emits as much greenhouse gas as if every car in the country was driven around the world twice.

“We hope that these numbers help policymakers see mangroves as a huge opportunity for climate change mitigation,” says Daniel Murdiyarso, principal scientist at CIFOR and lead author of the paper.

“It is time to acknowledge that mangroves must be part of the solution to climate change”

“But to make progress, it is crucial that mangroves are protected and managed sustainably. It is time to acknowledge that mangroves must be part of the solution to climate change.”

Dr Murdiyarso is also co-author of a CIFOR guide on climate change adaptation and mitigation in Indonesia’s wetlands.

In a separate study, published in the Royal Society Proceedings A, further light is shed on the crucial role mangroves play in protecting coastal areas from sea level rise caused by climate change.

The study, by researchers at the University of Southampton, UK, and colleagues from the universities of Auckland and Waikato in New Zealand, used mathematical simulations to discover how mangrove forests respond to elevated sea levels.

Mesh-like roots

When sea levels rise, they found, areas in estuaries and river deltas without mangroves are likely to widen from erosion, and more water will encroach inwards. But mangrove regions prevent this effect, probably because of soil building up around the trees’ mesh-like roots and acting to reduce energy from waves and tidal currents.

Dr Barend van Maanen, a coastal systems researcher in the department of engineering and environment at the University of Southampton, explains: “As a mangrove forest begins to develop, the creation of a network of channels is relatively fast. Tidal currents, sediment transport and mangroves significantly modify the estuarine environment, creating a dense channel network.

“Within the mangrove forest, these channels become shallower through organic matter from the trees . . . and sediment trapping (caused by the mangroves), and the sea bed begins to rise, with bed elevation increasing a few millimetres per year until the area is no longer inundated by the tide.”

In modelling of sea level rise in the study, the ability of mangrove forest to gradually create a buffer between sea and land occurs even when the area is subjected to potential sea level rises of up to 0.5mm per year.

“These findings show that mangrove forests play a central role in estuarine and salt marsh environments,” says Giovanni Coco, associate professor in the school of environment at the University of Auckland.

“As we anticipate changes caused by climate change, it’s important to know the effect sea level rise might have, particularly around our coasts.” − Climate News Network

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Climate threat as grave a risk as nuclear war

Climate threat as grave a risk as nuclear war

An international scientific report commissioned by the UK government says the risks of climate change are comparable to those posed by nuclear conflict.

LONDON, 18 July, 2015 – The UK government says that climate change poses risks that demand to be treated as seriously as the threat  of nuclear war.

Scientists from the UK, US, India and China say in a report commissioned by the UK that deciding what to do about climate change depends on the value we put on human life, both now and in years to come.

One of the lead authors of the report is Sir David King, formerly the UK government’s chief scientist, who last month co-authored a report on the scale of investment that should be made to move from fossil fuels to renewable energy by 2025. 

In a foreword to the latest report, Baroness Anelay, a minister at the British foreign office, writes that assessing the risks surrounding nuclear disarmament and non-proliferation means understanding inter-dependent elements − including what science says is possible, what other countries may intend, and systemic factors such as regional power dynamics.

“The risk of climate change demands a similarly holistic assessment,” she says.

Value human life

She concludes: “How much do we care about the effects of climate change? How important is it that we act to avoid them? What probability of their occurrence can we tolerate?…The answers to these questions depend in part on how we value human life – both now, and in the future.”

The report is not the first to put climate chaos and nuclear devastation in the same category of risk, but its sponsorship by one of the world’s nuclear powers is eloquent.

It says the most important political decision is how much effort to exert on countering climate change, taking into account what we are doing to the climate, how it may respond, what that could do to us, and what we might then do to each other.

The authors’ best guess, based on current policies and trends, is that greenhouse gas emissions will keep going up for another few decades, and then either level off or slowly decline.

“Uncertainty is not our friend. There is much more scope to be unlucky than there is to be lucky”

This, they say, is for two reasons: governments are not making maximum use of the technologies already available; and technology is not yet progressing fast enough to give governments the policy options they will need. In the worst case, emissions could keep on rising throughout the century.

They warn that how the climate may change, and what that could do to us, are both highly uncertain. “The important thing to understand is that uncertainty is not our friend,” the report says. “There is much more scope to be unlucky than there is to be lucky.”

High emissions pathway

The report foresees wide ranges of possible global temperature and sea level increase. On a high emissions pathway, it says, where the most likely temperature rise is estimated at 5°C by 2100, anything from 3°C to 7°C may be possible.

On this pathway, the chances of staying below 3°C will become “vanishingly small”, but the chances of exceeding 7°C will increase and could become more likely than not within the next century.

The authors see very little chance that global sea level rise will slow down, and every chance that it will accelerate. The only question is by how much.

“While an increase of somewhere between 40cm and 1m looks likely this century, the delayed response of huge ice-sheets to warming means we may already be committed to more than 10m over the longer term. We just do not know whether that will take centuries or millennia.”

A temperature increase of 4°C or more could pose very large risks to global food security, and to people.

Humans have limited tolerance for combinations of high temperature and humidity. Their upper limits of tolerance are rarely if ever exceeded by climatic conditions alone, but with temperature increase somewhere between 5°C and 7°C, it starts to become likely that hot places will experience conditions that are fatal even for people lying down in the shade.

Population growth alone is also likely to double the number of people living below a threshold of extreme water shortage by mid-century.

Sea level thresholds

Coastal cities, according to the report, probably have thresholds in terms of the rate and extent of sea level rise that they can deal with, but we have very little idea where those thresholds are.

The authors say that even the 0.8°C of climate change experienced so far is now causing us significant problems, and that “it seems likely that high degrees of climate change would pose enormous risks to national and international security” − for example, through extreme water stress and competition for productive land.

In a highly topical passage, they say migration from some regions may become more a necessity than a choice, and could happen on a historically unprecedented scale.

“The capacity of the international community for humanitarian assistance, already at full stretch, could easily be overwhelmed,” the report warns.

The risks of state failure could rise significantly, affecting many countries simultaneously, and even threatening those currently considered developed and stable.

But the report is not relentlessly downbeat. “An honest assessment of risk is no reason for fatalism,” it says. “Just as small changes in climate can have very large effects, the same can be true for changes in government policy, technological capability, and financial regulation… the goal of preserving a safe climate for the future need not be beyond our reach.” – Climate News Network

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Warming planet heightens plight of the bumblebee

Warming planet heightens plight of the bumblebee

Scientists warn that human intervention may be needed to protect bees as climate change overheats their southern habitat range.

LONDON, 10 July, 2015 − The humble bumblebee is feeling the squeeze from climate change. Research shows that its southern range is being reduced as the planet warms − and yet it seems to show no sign of migrating northwards to safety.

This unwillingness to head for cooler climes could prove disastrous, and has prompted some scientists to suggest that humans may need to intervene by creating refuges for the bees away from the heat.

Jeremy Kerr, a biologist at the University of Ottawa, Canada, and colleagues report in the journal Science that they generated a database of 423,000 local observations of 36 European and 31 North American species of the genus Bombus and mapped the patterns of change.

They found that in recent, increasingly warmer decades, bumblebees tended to disappear from the southernmost and hottest parts of their range, but did not shift north. In some cases, the insects’ range had shrunk by as much as 300 kilometres.

Dramatic losses

“Global warming has trapped bumblebee species in a kind of climate vice,” Professor Kerr says. “The result is dramatic losses of bumblebee species from the hottest areas across two continents.

“For species that evolved under cool conditions, like bumblebees, global warming might be the kind of threat that causes many of them to disappear for good.

“Unlike so many other species, bumblebees generally haven’t expanded into more northern areas. We may need to help these species establish new colonies to the north, and at continental scales.”

The finding is a clear indication that some naturally mobile species may not be able to adapt to climate change.

In recent decades, biologists have used animal and even plant migration to monitor climate change. Alpine species in Switzerland have been observed moving uphill, and in the UK, the butterfly range has tended to shift northwards.

In the latest study, the scientists looked at a range of factors that might limit bumblebee migration − things such as changes in land use, and pesticide prevalence, create problems for all wild species. But these factors seemed to play no significant part in limiting the creature’s range.

“Bumblebees are at risk, and the services
they provide are increasingly threatened
by human-caused climate change”

There is evidence that, where they can do, some species are moving uphill by as much as 300 metres, while still staying in the same latitude. But researchers do know that bumblebees don’t thrive in the extremes of heat that have been an increasing feature of recent decades.

“We don’t know for sure what is causing a stagnation at the northern end of things,” says Paul Galpern, a landscape ecologist at the University of Calgary, and a co-author of the report.

“Bees should be able to start new colonies in places they did not historically occupy. But we don’t know why this is happening so slowly that it looks like the ranges are not moving at all

“This all points to the fact that bumblebees are at risk, and the services that they provide are increasingly threatened by human-caused climate change.”

Important role

Such creatures play an important role in temperate zone ecosystems. “Bumblebees pollinate many plants that provide food for humans and wildlife,” says Leif Richardson, a biologist at the University of Vermont, and also a co-author of the report.

“If we don’t stop the decline in the abundance of bumblebees, we may well face higher food prices, diminished varieties, and other troubles.”

Professor Kerr reinforces the message. “Pollinators are vital for food security and our economy, and widespread losses of pollinators due to climate change will diminish both,” he says.

“We need to figure out how we can improve the outlook for pollinators at continental scales, but the most important thing we can do is begin to take serious action to reduce the rate of climate change.” – Climate News Network

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Stress on water resources threatens lives and livelihoods

Stress on water resources threatens lives and livelihoods

Satellite data raises red-flag warning about the draining of underground aquifers to meet the demands of expanding populations.

LONDON, 29 June, 2015 – The planet’s great subterranean stores of water are running out – and nobody can be sure how much remains to supply billions of people in the future.

Satellite instruments used to measure the flow from 37 underground aquifers between 2003 and 2013 have revealed that at least one-third of them were seriously stressed – with little or almost no natural replenishment.

The research was conducted by scientists from California and the US space agency NASA, who report in the journal Water Resources Research that they used data from NASA’s Gravity Recovery and Climate Experiment (GRACE) satellites to calculate what is happening to aquifers.

The two satellites measure variations in the gravitational pull of the planet’s surface, and have already revealed changes in the mass of ice sheets on the planetary surface. But buried water, too, has mass, and changes in the mass of bedrock in known aquifer regions would therefore offer a guide to depletion.

Driest regions

Not surprisingly, the researchers found that those regions that are already driest were drawing most heavily on the groundwater below the surface.

The Arabian aquifer system, − the principal water source for 60 million people − is the worst stressed, followed by the Indus Basin of north-west India and Pakistan, and then the Murzuk-Djado basin in northern Africa.

The scientists warn that climate change – a consequence of increasing atmospheric carbon dioxide emissions from the human combustion of fossil fuels – and population growth will make things worse.

“What happens when a highly-stressed aquifer is located in a region with socioeconomic or political tensions that can’t supplement declining water supplies fast enough?” asks Alexandra Richey, who conducted the research as a University of California Irvine doctoral student. “We’re trying to raise red flags now to pinpoint where active management today could protect future lives and livelihoods.”

“We can no longer tolerate this level of uncertainty, especially since groundwater
is disappearing so rapidly”

Her colleague, hydrologist James Famiglietti, identified his own home state of California as a cause for concern because it is in the grip of an extended drought that threatens agriculture.

“As we’re seeing in California right now, we rely much more heavily on groundwater during drought,” he says. “When examining the sustainability of a region’s water resources, we absolutely must account for that dependence.”

Groundwater accumulates slowly in the underlying bedrock over millennia. There is no problem if it is withdrawn slowly, but human population has exploded threefold in one human lifetime, and water use has risen even faster.

Supply problem

Research like this is a demonstration of ways to address a supply problem − but there is more work to be done.

In a second study in Water Resources Research, the same team examined the challenge of trying to calculate the rates at which aquifers are being emptied, and the uncertainties as to how much might remain in them.

In the Northwest Sahara, for instance, estimates of the projected “time to depletion” varied from 10 years to 21,000 years. “In a water-scarce society,” Richey says, “we can no longer tolerate this level of uncertainty, especially since groundwater is disappearing so rapidly.”

Professor Famiglietti concludes: “I believe we need to explore the world’s aquifers as if they had the same value as oil reserves. We need to drill for water in the same way that we drill for other resources.” – 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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India blames heatwave deaths on climate change 

India blames heatwave deaths on climate change 

Fierce temperatures in India doubled the heat-related deaths normally recorded in May − and the government insists natural causes are not to blame.

CHENNAI, 19 June, 2015 − India, one of the key players in the efforts to reach an international agreement on global warming, has no doubt of its malign effects. It was, says a government minister, the warming climate that caused last month’s devastating heatwave.

From mid-April till the end of May, nearly 2,200 people were killed by the heat − 1,636 of them in Andhra Pradesh, the worst-affected state. The normal May figure for the whole of India is about 1,000 heat-related deaths.

Dr Harsh Vardhan, India’s Minister of Science and Technology and Earth Sciences, has blamed the heat deaths squarely on climate change.

Improve understanding

Launching a supercomputer at the National Centre for Medium Range Weather Forecasting to improve understanding of climatic changes, he said: “It’s not just another unusually hot summer − it is climate change.

“Let us not fool ourselves that there is no connection between the unusual number of deaths from the ongoing heatwave and the certainty of another failed monsoon.”

Dr Vardhan said that May’s heatwave, followed by the delay to the start of the monsoon, on which nearly half of India’s farmlands depend, was a definite manifestation of climate change.

Jejabba, a 63-year-old farmer in Andhra Pradesh state, was one of those who lost their lives because of this year’s scorching heat.

He took his cows out to graze in a mango grove near his house around 11am, but was tired and dehydrated when he returned home four hours later. After he began vomiting, and then fainted, he was rushed to the small government hospital 5km from his village, but died on the way.

“In my 17 years of service, I have not
come across such an alarming number
of deaths due to a heatwave”

“Summer is severe, and many people have been affected by the heatwave in our village,” says Jejabba’s distant cousin, Pindigi Ramamurthi, who runs a grain store in the village. “Just the previous day, we took our two children to hospital after they began vomiting. The doctor admitted them for a few hours to administer fluids, and luckily that revived them.”

Local officials recorded Jejabba as “the latest of the summer deaths”. But when his widow asked for compensation − the state government pays 100,000 rupees (US$1,570) to the family of a victim − the local panchayat (civic) official, who has to recommend the payment, told her she must get a certificate from the hospital doctor.

“The doctor told the family he could not give the certificate because Jejabba did not die in his hospital,” Ramamurthi recalls. “Why couldn’t the poor fellow have stayed alive just an hour or so longer till we reached the hospital? Now the widow must suffer this red tape.”

In parts of southern India, daytime temperatures reached between 45° and 47°C during this year’s heatwave − up to 7°C above normal.

Alarming number

Dr Srihari Rao, resident medical officer at the government general hospital in Tirupati, about 45km from Jejabba’s home, says: “In my 17 years of service, I have not come across such an alarming number of deaths due to a heatwave.

“Almost every day in May there was a death in the district from sunstroke. The majority of the dead were in the 65 to 80 age group, but there was also a case of a 19-year-old girl dying from dehydration.”

Dr Rao said infants, aged people and farmers had been particularly severely affected.

The Intergovernmental Panel on Climate Change reported last year that there would be significant changes in the frequency and intensity of extreme weather events, including heatwaves in India. Its report was based on weather records from 1906 to 2005.

Researchers at the India Meteorological Department, after conducting a study of heatwaves over the last 50 years, have called for public information campaigns to be launched on the dangers, and also stressed the importance of using social care networks to reach vulnerable sections of the population. − 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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