Sunday, December 26, 2021

The meaning of net zero and how to get it right

Nature Climate Change (2021)Cite this article

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Abstract

The concept of net-zero carbon emissions has emerged from physical climate science. However, it is operationalized through social, political and economic systems. We identify seven attributes of net zero, which are important to make it a successful framework for climate action. The seven attributes highlight the urgency of emission reductions, which need to be front-loaded, and of coverage of all emission sources, including currently difficult ones. The attributes emphasize the need for social and environmental integrity. This means carbon dioxide removals should be used cautiously and the use of carbon offsets should be regulated effectively. Net zero must be aligned with broader sustainable development objectives, which implies an equitable net-zero transition, socio-ecological sustainability and the pursuit of broad economic opportunities.

Main

Climate policy has a new focus: net-zero emissions. Historically, climate ambition has either been formulated as a stabilized level of atmospheric concentrations (for example, in the 1992 United Nations Framework Convention on Climate Change) or as a percentage emissions reduction target (for example, in the 1997 Kyoto Protocol). Now climate ambition is increasingly expressed as a specific target date for reaching net-zero emissions, typically linked to the peak temperature goals of the Paris Agreement. Almost two-thirds of global emissions and a slightly higher share of global gross domestic product are already covered by net-zero targets1.

Net zero is intrinsically a scientific concept. If the objective is to keep the rise in global average temperatures within certain limits, physics implies that there is a finite budget of carbon dioxide that is allowed into the atmosphere, alongside other greenhouse gases. Beyond this budget, any further release must be balanced by removal into sinks.

The acceptable temperature rise is a societal choice, but one informed by climate science. Under the Paris Agreement, 197 countries have agreed to limit global warming to well below 2 °C and make efforts to limit it to 1.5 °C. Meeting the 1.5 °C goal with 50% probability translates into a remaining carbon budget of 400–800 GtCO2. Staying within this carbon budget requires CO2 emissions to peak before 2030 and fall to net zero by around 20502.

However, net zero is much more than a scientific concept or a technically determined target. It is also a frame of reference through which global action against climate change can be (and is increasingly) structured and understood.

Achieving net zero requires operationalization in varied social, political and economic spheres. There are numerous ethical judgements, social concerns, political interests, fairness dimensions, economic considerations and technology transitions that need to be navigated, and several political, economic, legal and behavioural pitfalls that could derail a successful implementation of net zero.

Getting net zero, the frame of reference, right is therefore essential. This Perspective recapitulates the scientific logic behind net zero and sets out the attributes we believe are important to turn it into a successful framework for climate action across countries.

The seven attributes complement an emerging set of operational principles and criteria, which have been put forward to govern specific net-zero decisions, such as country-level target setting3, the design of institution-level net-zero commitments (https://racetozero.unfccc.int/, https://sciencebasedtargets.org/ and ref. 4), the management and disclosure of climate risks5, and the use of carbon offsets6.

Net zero as a scientific concept

Net zero is just a number, begging the question ‘net zero what?’ For CO2, the answer emerged in the late 2000s from understanding what it would take to halt the increase in global average surface temperature due to CO2 emissions. A series of papers noted the longevity of the impact of fossil carbon emissions7,8,9 and the monotonic, near-linear (so far) relationship between cumulative net anthropogenic CO2 emissions and CO2-induced surface warming10,11,12,13. The corollary of this result is that CO2-induced warming halts when net anthropogenic CO2 emissions halt (that is, CO2 emissions reach net zero), with the level of warming determined by cumulative net emissions to that point.

Unless net CO2 emissions then go below zero, CO2-induced surface warming is expected to remain elevated at this level for decades to centuries14. This occurs because for, and only for, time intervals of 40–200 years, the rate of atmospheric CO2 uptake by the deep oceans (acting to reduce warming) occurs at a rate similar to the thermal adjustment of the deep oceans to raised atmospheric CO2 (acting to increase warming)9,15.

Total anthropogenic warming is a function not only of CO2, but also of a range of other greenhouse gases and forcings16. These have different efficacies and lifetimes of influence on climate, generally shorter-lived than that of CO2. Non-CO2 anthropogenic warming is therefore better determined not by cumulative emissions, but by the present-day emission rate plus a small correction for the long-term climate response to the average non-CO2 forcing over a multi-decade to century time interval17. Hence, the IPCC statement “reaching and sustaining net-zero global anthropogenic CO2 emissions and declining net non-CO2 radiative forcing would halt anthropogenic global warming on multi-decadal timescales2.”

These observations have an immediate policy implication: it makes little sense to apply the net-zero concept on timescales shorter than decades. Achieving net zero through an unsustainable combination of fossil-fuel emissions and short-term removals is ultimately pointless. Carbon emissions and removals must balance over multi-decadal timescales (Fig. 1).

Fig. 1: Net-zero balance of carbon emissions and removals.

We must also accept that net-zero emissions may still be associated with some further very slow warming or cooling on longer timescales, and that the temperature implications of the net-zero concept when applied to non-CO2 climate drivers are less clear than they are for CO2 alone, depending on the specific mix of drivers18.

There are alternative interpretations of net zero. Sometimes, net zero is used simply to describe emissions trajectories consistent with 1.5 °C (https://sciencebasedtargets.org/). While a helpful shorthand, this obscures the fact that halting global warming, at whatever temperature level, requires net-zero CO2 emissions and declining non-CO2 radiative forcing.

Alternatively, net zero is often understood to mean net-zero CO2-equivalent emissions aggregated using the 100-year ‘global warming potential’ metric. This cannot be related unambiguously to any temperature outcome, but is generally seen as more ambitious, and hence preferable, than ‘just’ halting human-induced global warming19. It may, of course, be necessary to aim for a long-term decline in global temperature. If so, the above empirical relationship remains applicable to determine what needs to be net zero to deliver this more ambitious goal. However, as we see it, the concept of net zero emerged from our understanding of what it would take to achieve a temperature goal, not vice versa.

The importance of these differences in interpretation should not be overstated: the fact that net zero needs to apply to a state of balance that can be maintained over multiple decades, meeting additional environmental and social criteria, limits the scope for compensation among different climate drivers. It also limits the scope for compensatory exchanges between different carbon pools in the atmosphere, biosphere, oceans and lithosphere.

The adoption of net-zero targets

The carbon budgets calculated by scientists apply to the global atmosphere, rather than individual entities. To turn net zero into a useful frame of reference for decision-makers, the global carbon constraint needs to be translated into individual decarbonization pathways for nation states, sub-national entities, companies and other organizations.

Setting such entity-level targets and defining how they interact requires judgement. There are many ways in which the remaining carbon budget can be managed. Although there is a considerable literature on this subject18,20,21,22,23, in practice defining the scope, timing, fairness and relevance of entity-level net-zero targets has been left to individual emitters and self-regulated voluntary codes. This leaves open the question of how a diverse set of voluntary pledges adds up to national targets and national targets add up to the global carbon budget.

The Paris Agreement leaves it to its parties to define their own emissions pathways or nationally determined contributions to global net zero. There is no official yardstick against which the adequacy, ambition or fairness of nationally determined contributions is measured. Instead, the Paris Agreement relies on process. Regular stocktakes are intended to catalyse ambitious action and ensure that national emissions pathways will gradually converge to a global net-zero state consistent with the long-term temperature goals.

More than 120 countries have now pledged to reach net zero in some shape or form around mid-century, consistent with the objectives of the Paris Agreement. They include China, the European Union and the United States, the world’s three largest greenhouse gas emitters.

Individual organizations are effectively accounted for in the carbon targets of the countries in which they operate, but many have made their own individual net-zero pledges. In doing so, they are guided by voluntary schemes, such as Cities Race to Zero, the Net Zero Asset Owners Alliance and the Science-based Target Initiative, which encourage entities to bring down their emissions as fast as reasonably practicable and many of which are partners of the United Nations’ Race to Zero campaign (https://racetozero.unfccc.int/). Progress is measured and assessed by frameworks such as CDP (https://www.cdp.net/en) and the Transition Pathway Initiative (https://www.transitionpathwayinitiative.org/).

At the time of writing, more than 100 regional governments, 800 cities and 1,500 companies have adopted organizational net-zero targets, often considerably earlier than mid-century1. One in five corporations in the Forbes Global 2,000 list have set a voluntary net-zero target.

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The meaning of net zero and how to get it right | Nature Climate Change

BC
District of North Van council calls for end of fossil fuels
Brent Richter Dec 20, 2021

District of North Vancouver council has joined a coalition of governments calling for a transition away from fossil fuels. (via Getty Images)

The District of North Vancouver has joined a growing coalition of local governments calling for an end to all new oil and gas infrastructure.

At their final council meeting of the year Dec. 13, district council voted to endorse the Fossil Fuel Non-Proliferation Treaty, a call for the rapid transition away from carbon-based fuels.

The motion from Coun. Megan Curren cites the hundreds of deaths from June’s heat dome, flooding, extreme forest fire risk and wildfire smoke, and sea level rise as consequences of the climate emergency.

The motion directs council to formally petition Premier John Horgan and Prime Minister Justin Trudeau to support the treaty.

“While there is much we can and must do at the local government level to keep DNV residents safe and healthy, local governments can also use our collective voices to drive system change at other orders of government,” Curren’s report states.

Along with the treaty, Curren’s motion affirms the district’s commitment to reduce community-wide carbon pollution emissions by 45 per cent, over 2007 levels, by 2030.

Advocacy group Force of Nature persuaded West Vancouver council to sign the treaty last month.

Because of particularly busy final council meeting of the year, Mayor Mike Little opted to move the vote to the consent agenda, meaning it was passed unanimously without any discussion along with several other agenda items.

Eight new substances added to U.S. carcinogen report

Christy Somos

CTVNews.ca Writer
Sunday, December 26, 2021

Chemotherapy is administered to a cancer patient via intravenous drip at Duke Cancer Center in Durham, N.C., on Thursday, Sept. 5, 2013.

THE CANADIAN PRESS/AP-Gerry Broome

A chronic bacterial infection, a flame retardant and some byproducts of water treatment processes have been added to a list of carcinogens identified in the U.S.

Eight entries have been added to the U.S. Report on Carcinogens, a cumulative report mandated by U.S. Congress to list substances that are known or are reasonably anticipated to cause cancer in humans.

In the 2021 15th Report on Carcinogens, the new entries added bring the total list up to 256 substances, according to a Dec. 23 news release.

The report is prepared by the U.S. National Toxicology Program for the Secretary of the U.S. Department of Health and Human Services. This year’s report coincides with the 50th anniversary of the U.S. National Cancer Act of 1971, signed into law by then-President Richard Nixon.

The report identifies environmental factors, chemicals, infectious agents, physical agents – such as X-rays -- and exposure scenarios but does not include estimates of cancer risk because of the many variables that can affect whether or not a person will develop cancer.

In the latest report, chronic infection with the bacterium known as Helicobacter pylori, or H. pylori, has been listed as known to be a human carcinogen.

H. pylori is a spiral bacteria that can enter the body through food, water or utensils, lives in the digestive tract and is behind most stomach ulcers. It is thought to penetrate the mucous lining of the stomach to establish infection and can lead to stomach cancer. It is more commonly found in countries with less established infrastructures surrounding clean water and sewage systems, but spread from one person to another is possible through saliva or other bodily fluids.

Another new entry to the report is the flame-retardant chemical called antimony trioxide, which in Canada is used for household items such as mattress covers, furniture and carpets.

It is also used in the manufacturing of the plastic material polyethylene terephthalate, or PET. Antimony trioxide is both manufactured and imported into Canada, according to Health Canada’s website.

Health Canada states that Canadians are “expected to be exposed to low levels of antimony trioxide from environmental media (soil, drinking water, ambient air) from food and from contact with household items.”

The agency says it conducted a screening assessment and “concluded that antimony trioxide is not harmful to the health of the general population at current levels of exposure.”

The final entries into the latest report include six haloacetic acids (HAAs), found as water disinfection byproducts, that are listed as reasonably anticipated to be a human carcinogen.

They are:
Bromochloroacetic acid (BCA)
Bromodichloroacetic acid (BDCA)
Chlorodibromoacetic acid (CDBA)
Dibromoacetic acid (DBA)
Dichloroacetic acid (DCA)
Tribromoacetic acid (TBA)

The HAAs are formed during the water treatment process, when chlorine-based disinfection agents react with organic matter in the source water.

Health Canada states that the maximum acceptable concentration for total HAAs in drinking water is 0.08 milligrams per litre, based on a locational running annual average of a minimum of quarterly samples taken in distribution systems.

“Cancer affects almost everyone’s life, either directly or indirectly,” said Rick Woychik, Director of the U.S. National Institute of Environmental Health Sciences and NTP, in the release. “As the identification of carcinogens is a key step in cancer prevention, publication of the report represents an important government activity towards improving public health.”

SEE

Bookchin M. Our Synthetic Environment.pdf (libcom.org)

A seed for all seasons: can ancient methods future-proof food security in the Andes?

In Peru’s remote villages, farmers have used diverse crops to survive unpredictable weather for millennia. Now they are using this knowledge to adapt to the climate crisis

Men in Ccachin, a village near Cusco, Peru, meet to drink chicha, made from fermented maize, before working in the fields. Photograph: Dan Collyns/The Guardian

Global development is supported by

Dan Collyns in Choquecancha

Sat 25 Dec 2021 10.01 GMT

In a pastoral scene that has changed little in centuries, farmers wearing red woollen ponchos gather on a December morning in a semicircle to drink chicha, made from fermented maize, and mutter an invocation to Pachamama – Mother Earth – before sprinkling the dregs on the Andean soil.

Singing in Quechua, the language spread along the vast length of the Andes by the Incas, they hill the soil around plants in the numerous small plots terraced into a patchwork up and down the Peruvian mountainside.

The Andes sustains one of the most diverse food systems in the world. Through specially adapted farming techniques, these farmers conserve a great variety of maize, also known as corn, and other biodiverse crops that could be key to food security as global heating causes a more erratic climate. Maize has been grown in Lares, near Cusco, for thousands of years, in one of the highest farming systems in the world. Choquecancha and Ccachin communities specialise in more than 50 varieties of the cereal in a myriad of different sizes and colours.

It would be difficult to produce one variety of one crop. In one year you have frosts, hail, droughts or torrential rainJavier Llacsa Tacuri, agrobiodiversity expert

“In the old days, the Incas grew these ecotypes and now we continue the path set down by our ancestors,” says Juan Huillca, a conservationist in Choquecancha, a tiny mountainside village.

On a blanket are ears of corn ranging in colour from faintly yellowed white to deep purple. All have thick kernels and evocative names. Yellowish corncobs with red tinted kernels are called yawar waqaq (blood crier). White cobs flecked with grey, whose toasted kernels are served as crunchy canchita with Peru’s flagship dish ceviche, are more prosaically called chuspi sara (small corn).

Historians believe what is now the world’s most widely grown cereal crop was first domesticated by people in modern-day Mexico about 10,000 years ago and subsequently spread south down the spine of the Andes to reach Peru about 6,000 years ago.

Maize from Lares province near Cusco, where the crop has been grown for thousands of years. Photograph: Dan Collyns/The Guardian

Long before the climate crisis, these farmers’ ancestors adapted to growing crops in different niche ecosystems, from icy mountain peaks to sunny valleys.
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“In this landscape it would be difficult to produce just one variety of one crop, because in one year you can have frosts, hail, droughts or torrential rain,” says Javier Llacsa Tacuri, an agrobiodiversity expert who manages a project to safeguard the farming techniques, which have been identified as one of a handful of globally important agricultural heritage systems.

“With a few varieties, you could not face a farming year, so the response is to have many varieties. The frosts and hailstorms have always occurred and their ancestors knew how to face them,” he says.

With more than 180 native domesticated plant species and hundreds of varieties, Peru has one of the world’s richest diversity of crops.

Backed by the UN’s Food and Agriculture Organization, the project supports the farmers to preserve the native species, and Llacsa Tacuri and colleagues help find markets for the multicoloured corns.

“Peru is one of eight places in the world which is considered a centre of origin for agriculture,” says Llacsa Tacuri. “The first inhabitants and their descendants – the peasant farmers who are here – started their adaptation to this landscape more than 10,000 years ago.”

Huillca says his village and its neighbours are already feeling the climate crisis.

“Diseases like stem rust or blight arrive, sometimes we get frost or hail. That’s why we have our seed bank in order not to lose our maize ecotypes, so we can recover what we’ve lost and resow those varieties,” he says.

‘We continue the path set down by our ancestors,’ says Juan Huillca, farmer and maize conservationist, Choquecancha, near Cusco.

Photograph: Dan Collyns/The Guardian

In a simple farmhouse in Ccachin lies the genetic heritage of thousands of years of crop domestication and variation. Dozens of types of dried kernels are stored in plastic containers for rainy days.

“But many young people migrate to the city because this doesn’t generate much income,” Huillca adds. “What we do doesn’t bring enough income to sustain the family, so they move to the city.”

‘Hidden pandemic’: Peruvian children in crisis as carers die

Sonia Quispe, a maize conservationist in Choquecancha, says the harvest is half what it would normally be.

“With the climate crisis, there’s less harvest, but we substitute our diet with potatoes,” she says. “It’s important to work with the different varieties of maize for our food security. With global heating, there are varieties that are more resistant to illnesses and pests.”

Quispe can identify the variety of three-month-old maize shoots from the stalks. She explains that the ones with red at the base will produce red-tinted cobs with a bitter taste that repels pests, which are moving further up the mountain as the sun becomes more intense.

Maize is collected and stored in a seed bank in Ccachin to prevent varieties being lost. Photograph: Dan Collyns/The Guardian

Julio Cruz Tacac, 31, a yachachiq, or farming teacher, who returned to Ccachin after studying in Cusco, has seen weather patterns change.

“When I was little, the sun didn’t shine with such intensity, the temperature was mild,” he says.

“It’s as if we live in an Eden in terms of food products, we have everything to hand,” he says of his childhood home. This is in contrast to city life, where “everything is money”, he says, and which became even harder during the Covid-19 pandemic – Peru had the world’s highest Covid mortality rate.

The custom of ayni, reciprocal communal work, remains in these remote villages, but a bartering form of exchange, known as trueque, has been hit by the pandemic’s economic impact.

‘With the pandemic the people don’t want to barter, they want money,’ says Genara Cárdenas, a farmer in Ccachin, Cusco.

Photograph: Jorge De La Quintana

“We go to the market and we trade with the fruit and coca from the farmers in the valley,” says Genara Cárdenas, 55, from Ccachin. “But now with the pandemic the people don’t want to barter, they want money.”

Financial pressures have affected the village’s traditional way of life, but their crops have helped them remain self-sufficient despite the economic problems.

Even so, the climate crisis presents new challenges, says 55-year-old farmer Victor Morales.

“When I was young, the rains, the frost, all had their time. But today everything has changed. We had many types of potatoes and maize, now we have varieties which are more resistant to climate change.”

IRELAND

Eco-friendly farmer hails wrapping fields in cover crop ‘blankets’ over winter

Eugene Ryan, right, with son Eoghan and father Hugh on the family farm in Portlaoise

26/12/2021
BY DAVID YOUNG, PA

An eco-friendly Irish farmer who was recognised with a new sustainability award says he is reaping the environmental benefits of wrapping his fields in colourful “blankets” every winter.

Eugene Ryan (49) from Portlaoise, is the third generation of his family to make barley used to brew Guinness.

He is one of a group of tillage farmers in Ireland who have adopted the use of cover crops in fields that would have previously laid bare during the winter months after the cash crops have been harvested for the year.

Eugene Ryan’s son Eoghan and the family’s dog Brandy

in the cover crops. Photo: Eugene Ryan/PA

The practice has been credited with reducing the farmers’ carbon footprint while improving soil fertility and limiting erosion caused by heavy rainfall.

Mr Ryan, a married father-of-two, plants a range of winter flowers and vegetables in his fields that grow through autumn and winter and create a thick barrier from the harsh elements.

The colourful mix of plants has also created a new habitat for insects and wildlife, with bees and pheasants particularly fond of the dense vegetation.

“The cover crops do a number of things to protect the soil over the winter,” Mr Ryan said.

“They soak up any nutrients that might be left in the soil once a crop has been harvested and they help to create organic matter that we then reincorporate into the soil and they also help protect the soil from heavy rainfall.

“So, it’s like having a large blanket on the soil.”

Eugene Ryan with his sustainability award. Photo: Diageo/PA

He added: “I’m certainly a lot happier to have a green cover on the field rather than bare soil which would have been the traditional way.”

Mr Ryan has also experimented with eco-friendly ways of clearing the cover crops ahead of sowing season, rather than relying on herbicides.

One method is to wait for a heavy frost and then drive over the fields with a roller.

“Because the crop is frozen solid it just shatters when you drive over it and that kills the crop and it breaks down,” he explained.

The farm, which has been in the Ryan family for more than 100 years, grows barley, wheat, oats and oil seed rape for market.

It is the spring barley that is used to brew Guinness. The farmer’s work with cover crops helped him scoop the inaugural Guinness Sustainability Award at this month’s Irish Malting Barley Excellence Awards.

Mr Ryan said he had to take a long-term view when justifying the effort to sow a crop that made no immediate profit.

The tillage industry has a huge role to play in sequestering carbon. We're not quite carbon neutral, but we’re very, very close to it. So the protection of the tillage industry is of vital importance going forward

Eugene Ryan

“The benefits can be somewhat hard to quantify or put an exact monetary figure on it,” he said. “Certainly, I’ve seen the difference and I would say my soil has become a lot healthier.”

The farmer said his fields had also become a bit of local attraction for people in the area.

“I suppose if you’ve a field of wheat or barley it all looks the same, as it looks the perfect height and it’s nice and even, whereas this can look maybe a little bit ungainly because there are big plants and small plants and all sorts of colours in it,” he said.

“It’s certainly eye-catching but the benefits are huge from it.”

Mr Ryan insists that tillage farming in particular is one of the most carbon efficient industries in Ireland.

“The tillage industry has a huge role to play in sequestering carbon,” he said.

“We’re not quite carbon neutral, but we’re very, very close to it. So the protection of the tillage industry is of vital importance going forward.”

Plant protein revolution is shaking up agriculture

Plant protein growing

Sylvain Charlebois - Dec 26, 2021 / 11:00 am | Story: 355208

Photo: Contributed

The global plant protein market could double by 2026, reducing the need for meat

While there are those who demand greater access to agricultural land for city dwellers, especially since COVID-19 has pushed many to seek space far from major cities, others want to protect our land from real estate speculators.

It’s a real point of tension and an important debate. But beyond this, our approach to protecting farmland may have to change forever.

Two reasons often motivate governments to protect farmland.

First, many loudly proclaim the impossibility of creating agricultural land. While true to a certain extent, technologies allow us to repurpose land and make our acreage more efficient. And there are vertical farms. The greenhouse industry allows increased efficiency of our spaces and is expanding rapidly in Canada and elsewhere.

Also, our debate on farmland protection is based on the premise that consumers will continue to consume in the same way for years to come. But consumers’ habits are changing – slowly, but they’re changing. With our collective craze for plant-based proteins and the eventual arrival of emerging technologies like precision fermentation and cultivated meat that will shake up our plates, protein will mean something quite different in a few decades.

A real transition to plant proteins is shaping up. Most Canadians will continue to consume meat, but in smaller quantities for all kinds of reasons. According to a report by the Market Data Forecast group, the global plant protein market could double by 2026. This market is estimated at around $23 billion now, so it could exceed $46 billion in a few years.

That huge progression is just the start of a new trend. And don’t let Beyond Meat’s current slide fool you. The younger generations are interested in protein that’s more sustainable, simpler and less expensive. Given higher meat prices, retail price differences between vegetable and animal proteins are much less significant than a few years ago.

In Canada and around the world, agricultural land devoted to food production for livestock is substantial.

Major field crops include all varieties of wheat, barley, corn, oats, rye, canola, flax, soybeans, dried peas, lentils, dried beans, chickpeas, mustard seeds, canary seed and sunflower seeds. Our grain output is massive.

According to the Animal Nutrition Association of Canada, 80 per cent of the barley, 60 per cent of the corn and 30 per cent of the wheat crops grown in Canada are used to feed livestock. And according to Statistics Canada, about 15 million acres are used to produce these three crops for livestock in Canada – and 15 million acres is almost the size of New Brunswick.

Some of the land will obviously be repurposed and given over to other crops since the pressure to grow crops for livestock could drop significantly over time.

Cultured meat is also on the horizon, along with other technologies that require fewer resources. For example, the aquaculture production of fish and seafood could double in the next few years, giving more protein options to consumers.

You can understand where this is all going. A greater plurality of proteins will require more modest agricultural production.

As for milk, the darling of Eastern Canadian agriculture, precision fermentation could wipe out Canada’s dairy industry within 15 to 20 years, according to reports.

So protecting farmland isn’t the only issue we need to worry about. We also need to think about land occupancy in rural communities.

Despite this, the threat of running out of farmland to feed the planet by 2050 continues to be expressed. Certain groups are worried about the possibility of running out of food to feed our 10 or 11 billion people by 2050.

But according to the United Nations, 40 million square km, or 77 per cent of agricultural land in the world, is dedicated to animal production. It’s a safe bet that we won’t run out of agricultural land – just the opposite could happen. Experts even say climate change can give Canada new land in the North to cultivate crops.

We will have to find new ways of occupying our rural territory, not just protect it. The management of our agricultural heritage and the support offered to rural economies will undergo a major upheaval. Farmland management in Canada will change, and it needs to, for the sake of our rural communities.

Sylvain Charlebois is senior director of the agri-food analytics lab and a professor in food distribution and policy at Dalhousie University.

‘Near impossible’ plant-growing technique could revolutionise farming

For the first time, grafting has been made to work in monocots, a type of plant including oats, wheats and bananas – and it might improve disease tolerance among these important crops

ENVIRONMENT 22 December 2021

By Alex Wilkins

**A date palm two-and-a-half years after grafting. Inset shows a region at the base of the plant,**
**with the arrowhead pointing to the graft site**
Julian Hibberd

A new technique for grafting plants could increase production and eliminate diseases for some of the world’s most imperilled crops, such as bananas and date palms.

Plant grafting, where the root of one plant is attached to the shoot of another, has been used in agriculture for thousands of years to improve crop growth and eradicate diseases, in plants such as apples and citrus fruits. But this technique wasn’t thought to work for a major group of plants: the monocotyledons (or monocots). This group includes all grasses like wheat and oats, as well as other high-value crops like bananas and date palms. These plants lack a tissue called vascular cambium, which helps grafts heal and fuse in many other plants.

Now, Julian Hibberd at the University of Cambridge and his colleagues have found an approach that allows monocots to be grafted. They extracted a form of embryonic plant tissue from inside a monocot plant seed and applied it to the potential graft site between two monocot specimens belonging to the same species – wheat, for instance.

The tissue stimulated growth and fused the two plant halves together. The research team used fluorescent dyes to verify that the root and shoots had fused and could transport liquids and nutrients up and down the stem.

“I have written on the record that I thought it was near impossible. So, as a science breakthrough, it’s pretty amazing,” says Colin Turnbull at Imperial College London.

The method appeared to work on a wide range of monocot plant families, including important crops such as pineapple, banana, onion, tequila agave, oil palm and date palm. The team’s preliminary studies in the lab also suggest that the grafting can work between species. They grafted a wheat shoot to disease-resistant oat roots. This may protect the wheat from soil-borne disease, although it is still unclear whether this protection would be feasible in the real world

Hibberd, who worked on the research after a proposal from his colleague Greg Reeves, was initially hesitant. “Everyone said you can’t do it, so I didn’t want [Reeves] to dedicate a PhD to trying something that everyone says you can’t do,” says Hibberd. ”It’s a beautiful thing. It’s science at its best, where you find something out even though everyone says it’s not possible, and he proved me wrong.”

The technique could be especially useful for combating disease in vulnerable species like the Cavendish banana, which forms the vast majority of the world’s supply. Unable to reproduce sexually, the Cavendish is only reproducible by cloning, meaning the crop is highly genetically uniform and so vulnerable to diseases like Panama disease, which is caused by a soil-borne fungus.

By grafting more disease-resistant stems (or rootstocks) with the banana plant, the Cavendish could avoid Panama disease.

The procedure may not be feasible for grasses like wheat and oat, as the process would have to be repeated millions of times for a single harvest. But for large plants that live for many years and generate high-value produce, like date palm or tequila agave, the method could prove to be cost-effective.

One of the most immediate uses for the procedure could be in research labs, where grafting is already used regularly to understand how dicots transport material up and down the stem.

Journal reference: Nature, DOI: 10.1038/s41586-021-04247-y

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