TREES: Plant trees in lawns, roadsides, parking spots.

Eleven percent of all global greenhouse gas emissions caused by humans are due to deforestation[i] — an amount comparable to the emissions from all passenger vehicles on the planet. We need to keep and increase our forests.

The Crowther research group in Zurich was first to count the world’s trees.[ii] They estimate that the world now has three trillion trees and that we need an extra one trillion to reduce global warming. This trillion has become a widely accepted goal, though overly optimistic. One trillion equals 1,000 billion. Canada has boldly promised to plant two billion trees, but so far, shows little progress toward that goal.

The Crowther group mapped the best global locations for trees to grow and purposely omitted planting in urban districts or farmland. Thus, most of their anticipated locations are far away from human beings, though if a tree is to have a high probability of surviving, it needs to be weeded and watered for two years after being planted. Also, Crowther expected new forests to grow in the Arctic – and, unfortunately, that prediction may be right. Trees are encroaching everywhere in the Arctic,[iii] though they have a net heating effect and therefore should be eradicated from permafrost areas, not encouraged.

So where should trees be planted, and who can tend them? It is possible for drones to do the planting, for each drone can plant thousands more trees per day than any person. However, those trees have high mortality rates, so very few drone-planted trees become mature. Unfortunately, drone-planting companies are secretive about the survival rates of their trees.[iv] Nowadays seeds are in short supply because tree-planting is popular, so scientists cannot afford to waste them on experiments in which 80 percent of the seeds might not survive. Consequently, at present it makes no sense to plant trees in remote areas by drones and expect most of them to mature.

On the other hand, deforested areas often can regenerate themselves without having any trees planted at all. Trillions of seeds are constantly being dispersed in nature, some of which, against all odds, become trees. Merely protecting a place from fires and logging will give it an opportunity for self-renewal. However, this type of spontaneous regrowth won’t yield Canada’s promised two billion on schedule and we can’t expect a trillion more trees on the planet any time soon.

But the Crowther group was wrong in omitting farms and cities from their projected sites for new forests. Indeed, those are the ideal places to plant trees because the best planters, weeders, and waterers are human, and humans mainly live in cities or travel on country roads. Also, trees directly cool cities and make them more habitable. So, how much can we increase the canopy cover over people? Here are my estimates.

According to Google, Canada has more than a million kilometers of roads, including expressways, unpaved country roads, and city streets. How many trees can we plant on both sides of those roads? Since there are obstacles (e.g. intersections, sidewalks, and already existing trees) we can plant along only, say, 500,000 of the one million kilometers.

Trees thrive best when planted close together. The Miyawaki system plants four per square meter, though not all of them survive, so let’s plant ours three feet apart. 1 km = 3280 feet.  And 3280/3= 1093 trees. But let’s plant on both sides of the road, so 1093 X 2 =2186.7 which rounds up to 2187 trees per km. Along the 500,000 km of Canadian roads, streets, and expressways we can add almost 1.1 billion trees where people can water, weed, and hug them. Hooray!

   But wait – it gets better! Within 12 or 15 years, our streets will be full of electric, driverless trucks and taxis (so cheap that you won’t want to own a vehicle). They’ll stop to pick up and unload but won’t park. Today’s parking spots and lots will be empty. Let’s plant trees in those parking spaces!

        Google says: “Canada has 71 to 97 million parking spaces: 3.2 to 4.4 parking spaces for every vehicle in Canada.” Suppose we plant just one tree per parking space in only 50 million of those spaces. That adds 50 million trees to the 1.1 billion we plant along roads, bringing our total up to 1.15 billion.

      Next: Google says that there are about 6.2 million lawns in Canada. Suppose only half of each lawn is turned into a Miyawaki forest. This space Google estimates as totalling 28,800 hectares. Miyawaki forests are extremely diverse, each small one ideally including many different species of native origin. When mature, these forests contain up to 2.5 trees of varying size per square meter,[v] but let’s set our estimate more conservatively – at 1.5 per meter. A hectare is 10,000 square meters, so a Canadian hectare of Miyawaki forest will have 15,000 mature trees, and 28,800 X 15,000 = 432 million.

      Thus, if half of Canadian lawns are converted to forests, we can add 432 million trees to the 1.150 billion that we’ll plant along roads and parking spots. That makes 1.582 billion trees, bringing Canada closer to its promise of adding two billion, while saving birds, water, fertilizer, and preventing mowers from emitting carbon.

         Google reminds us: Canada has 347 million hectares of forest (just under 900 million acres), and each hectare of mature forest can absorb about 6 tonnes of CO₂ per year, so by my calculations, the existing Canadian forests capture over two billion tonnes of COs each year. But unfortunately, forests do not just store carbon — they also release it. Millions of tonnes of CO₂ are emitted as trees die and decompose, are disturbed by insects like the mountain pine beetle, or are burned in forest fires. Fires in the boreal forest release about 170 tonnes of carbon dioxide per hectare burned. And I will leave it to others to guesstimate how much CO2 our proposed additional 1.582 billion trees will sequester.

People love trees and feel cooler when buildings are surrounded by them, so this estimate is achievable as a goal. But let’s face it: Even if each of the world’s 193 countries added two billion mature trees to the planet (which is an unrealistic goal) the result would only be 386 billion trees — not the two trillion we hope for. And drones may or may not make up the difference.

There are two conclusions: (a) Do not count on trees alone to save us, and (b) let’s plant them anyway. Trees are part of the solution, and probably the most delightful part. [vi] This much is clear: Saving existing trees can achieve greater reductions in global warming than planting new ones. But let’s do both, as much as possible.

        What is the best way to organize an urban tree-planting program across Canada? Let’s consider two very different alternatives, though in fact we can combine the two.

        First: The government could hire several big companies and have hard-hat wearing guys do the job with jackhammers and steam shovels. That’s normal for a modern society. That efficient approach was used when Stockholm, Sweden planted 30,000 or 40,000 trees in that city.[vii] About 1/3 of their old trees were dying and had to be removed; life is hard for urban trees because of compaction and lack of penetration by rainwater. The city’s engineers dug up pavements, laid down substrates of stones or recycled concrete chunks, filled the cracks between them with soil, and planted the root-balls of new trees into a mixture of gravel and biochar. At the top surface, each tree was surrounded by a metal grill that allowed water to flow in and, around that, covered with tiles that allow water to penetrate the cracks and be consumed by the trees instead of leaching pollution into the sea. The urban forest is flourishing. Canada could emulate Stockholm.

Second: China offers a contrasting model for the large-scale restoration of degraded land by millions of individual workers. An area in China the size of France had been barren desert for about a thousand years when the government started the project, which lifted out of poverty more than 2.5 million people. Local inhabitants were paid to do the work manually, building terraces across all the hills.[viii] 

The  filmmaker John Liu[ix] observed this process while making a documentary about it,[x] and was so impressed that he has created “ecosystem restoration camps” where volunteers create new forests in several Western societies.[xi] Some of them really are camps where summer vacationers spend a few weeks restoring nature; others are year-round communities that have organized to revive their own environment. All of them, says Liu, are places where people have fun together, developing friendships and community spirit.

Canada may benefit more from coordinating a project of this type than from Sweden’s excellent mechanized approach. School children can be taken to forest expeditions to collect seeds of native trees, then plant them in coffee cans. The government can provide the saplings, tools, instruction manuals, and organic amendments such as biochar, rock dust, and seaweed and encourage Canadians to plant trees in their own neighborhoods. Able-bodied members of churches, Parent-Teacher committees, and meditation clubs will work together enthusiastically on weekend projects to save the planet, given such an opportunity. But yes, some jackhammer crews will be needed too.

CONCRETE: Use carbon-negative concrete in all government-funded construction

Concrete is the second-most used substance in the world, after water,[xii] and is the source of eight percent of the world’s carbon emissions. CO2 is emitted both from the energy used to fire the ingredients of Portland cement and as a chemical reaction while the mixture is being heated. According to the National Ready Mixed Concrete Association, each pound of ordinary concrete releases 0.93 pounds of carbon dioxide – and the world consumes 4 billion tons of cement each year.

But only 10% to 15% of concrete is cement, whereas 60% to 75% of it is aggregate, in the form of sand and gravel. The rest is water and air. Numerous companies are using various ways of reducing the total carbon emissions from producing concrete, and the most promising company, Blue Planet, actually produces a concrete that is net carbon negative.

It is impossible to reduce the carbon footprint of the Portland cement much because the first step is to make clinker, which is typically a mixture of calcium carbonate, clay, and gypsum heated in a kiln. This heat must be very high – around 1500 degrees, and much heating inevitably creates lots of CO2 emissions while the clinker is undergoing calcination; the calcium carbonate breaks down into calcium oxide, releasing even more CO2. There is no better way of obtaining cement, though some concrete companies replace some of the cement with fly ash created by coal-powered plants or slag from the furnaces that produce steel.

However, one company, Blue Planet, makes carbon-negative concrete by producing a limestone aggregate that is far more carbon-negative than the cement is carbon-positive. It does so by capturing CO2 from a local source (e.g. emissions from a nearby smokestack, or even CO2 emitted by a cement kiln) to form a carbonate, which is combined with waste concrete to form synthetic limestone pellets – the aggregate component of Blue Planet concrete. This process subtracts CO2 from the air or a source of emission and makes it into a durable, carbon-negative concrete – a permanent carbon storage material.

I interviewed Brent Constanz,[xiii] the inventor and head of the California company, whose website [xiv] declares that its mineralization technology is

“the only known scalable method for capturing and permanently sequestering billions of tonnes of CO2. Our process can use dilute CO2 from any source, at any concentration, and turn it into valuable building materials to enable carbon capture at a profit. Each tonne of our aggregate permanently mineralizes 440 kg of CO2, preventing it from ever leaking or accumulating in the atmosphere.” 

The world is currently emitting about 35 billion tonnes of CO2 per year. However, Blue Planet’s website proudly declares: “If we replace just 16% of all aggregate used today with Blue Planet Aggregate, we could achieve the CO2 storage needed by 2050 to keep temperature rise below 1.5C.”

How much does Canada contribute to the world’s production and consumption of cement? According to Statistics Canada, in 2018 Canada produced over 13.5 million metric tonnes of cement. Of course, cement is only one component of concrete (sand, aggregate, and water are the remaining components) so this figure does not tell us how much would be sequestered if Canada’s concrete were made solely with Blue Planet’s aggregate, but the Pugwash researchers may be able to reach such an estimate with publicly available information.

Several other companies – including at least one based in Canada – are producing concrete with lower CO2 emissions than the amount from conventional concrete, though I don’t think any of them produce “net negative” concrete. However, it is useful to compare all of them when appraising the potential of concrete as a means of reducing global warming. So long as carbon-negative concrete is scarce (as may be the case for a few years), conscientious users may at best choose a low-emissions concrete instead.

The transition to carbon-negative concrete does not require government subsidies, since the concrete industry is profitable and growing, and there are plenty of financial incentives for carbon reduction. Indeed, ordinarily (depending on transportation costs) carbon negative concrete is less expensive than the conventional kind.

The best contribution of the government would be to specify that only negative carbon concrete be used, whenever available, in the construction of all publicly funded infrastructure work. This kind of governmental promotion is happening elsewhere. For example, Blue Planet is creating numerous new plants in China, and the newest terminal and runway in San Francisco’s airport were made from Blue Planet’s concrete.

The concrete industry has called upon the government to “prioritize strategic spending to provide a needed boost for publicly funded infrastructure projects.”[xv] They did not intend to boost carbon negative concrete, but Pugwash can propose that additional proviso.

HUDSON BAY ICE: Brighten clouds over Hudson Bay

Solar Radiation Management (SRM) can be implemented quickly at moderate cost. Because it does not reduce CO₂ levels, it will not solve such problems as ocean acidification, but it can offer immediate cooling, which may relieve local problems and give us enough time to solve other aspects of the climate crisis.

Two major types of SRM method have been proposed to date. First, some have proposed the injection of solid particles at high elevations from balloons or jet planes, to form aerosols that reflect incoming radiation. High-altitude particles can indeed affect climate. For example, for three years after 1992, when Mount Pinatubo erupted, there was a noticeable cooling of the planet.

Although this technological solution would not be too expensive, potential problems loom. Rainfall would be reduced, affecting the Asian and African monsoons. The ozone hole might expand, and it is uncertain how the effect might vary for different countries. It might even warm some countries while cooling the planet as a whole. Many people understandably oppose any plan that would emit possibly toxic materials into the upper atmosphere. Hence, I exclude that approach here, while promoting the second version of solar management of radiation: Marine Cloud Brightening (MCB).

Professor John Latham of the University of Manchester was first to propose “whitening” low-level clouds over the oceans by spraying very fine particles of saltwater. The drops composing white clouds are smaller than those composing dark clouds, and therefore white clouds have more albedo; by reflecting more incoming solar radiation they cool the land or water beneath them.

I have held numerous conversations about cloud brightening with a marine engineer, Professor Stephen Salter of Edinburgh University, who has designed systems of saltwater spraying,⁶ and with Professor Peter Wadhams of Cambridge University, a foremost authority on Arctic sea ice. There is apparently agreement among scientists that the global warming problem could solved by increasing the reflectivity of the earth by about 0.5% (1.7 watts per square metre out of 340). Canada cannot do the whole job, but it can adopt this technology and demonstrate its effectiveness within five years by preserving sea ice over part of a body of water within its own territory: Hudson Bay.

Marine cloud brightening (MCB) works by reflecting more sunlight back into space from the tops of thin, low-level clouds (marine stratocumuli, which cover about a quarter of the world’s oceanic surface). By increasing the whole planet’s reflectivity, the cooling could balance the global warming caused by increased CO₂ in the atmosphere.

Each cloud drop forms around a tiny condensation nucleus. Salt fragments from the evaporation of sea water make ideal nuclei in humid conditions, such as over oceans. When wind blows over the sea it produces turbulence and some of the spray droplets rise and evaporate, leaving the salt particles to become the nuclei of new cloud drops that remain aloft until washed out as rain. Doubling the number of cloud drops will increase reflectivity by just over 5 percent.

Thus, we can whiten the clouds by spraying a fine mist of sea water over the oceans, which will cool the water or sea ice below. This can be done from a fleet of small ships or, in the case of Hudson Bay, even from stations on shore or on islands spraying clouds over the sea ice.

The electricity required for spraying and communications can be produced by current turbines at the spraying stations or built into the ships. The essential part of the equipment is a nozzle capable of producing droplets of the required diameter that, when they evaporate, leave a tiny salt particle that becomes the nucleus of a cloud drop (26% solution) that brightens the cloud. This creates the “Twomey effect” which can be seen in photos of the oceans taken from space: Ships create brighter clouds that resemble contrails by leaving saltwater spray in their wake.

To reduce the world’s overall climate with this approach, hundreds of ships would be required. Fortunately, the plan is ecologically benign, the only raw material required being sea water. The cooling could be controlled via satellite measurements and a computer model. If an emergency arose, the system could be switched off, with conditions returning to normal within a few days. There is no danger that the clouds will block the sunshine needed for agriculture, for the only clouds that will be brightened are those over water, not land.

Not all the necessary equipment has been perfected yet, with the nozzle design being the most challenging. The size of the saltwater droplets must be very tiny and quite precise. Several organizations are already working on designing and testing nozzles, and Salter has been working with a manufacturer that he expects can produce the ideal nozzle in three or four years with a budget of about £300,000. The easiest material to start with is monocrystalline silicon, the most popular material for making micro-chips.  It is strong enough for 200 mm diameter wafers, but notch-sensitive.  One tiny crack can spread across the whole wafer.  There are lots of more expensive, less notch-sensitive materials but the cost will be learning how to use them. Salter would like to be sure that, say, £20 million (Can $30.4 million) will be available for the project if he can show he can make mono-disperse spray in small quantities.

It is possible to apply cloud brightening on a local region instead of the whole planet. The brightened clouds, if regionally targeted, can moderate hurricanes (which depend on sea surface temperature) or reduce coral reef bleaching. For example, I interviewed Daniel Harrison, a professor at the Southern Cross University in Australia, who is leading a project to spray saltwater into clouds over part of the Great Barrier reef, thereby reducing the water temperature enough to prevent further bleaching of the corals.

Peter Wadhams is addressing the urgent question of cooling the Arctic. The open water over the Arctic continental shelves in summer allows warming of the subsea permafrost and a potential methane catastrophe. But could this be prevented by bringing back the summer sea ice without necessarily having to cool the entire planet?

Wadhams was one of a group that addressed this regional question in 2014. They found that it is possible to advance Arctic sea ice significantly. Global seeding can also increase the area of Antarctic sea ice and cool the currents that now are expected to cause Antarctic glaciers to collapse and raise the global sea level by up to three meters.

Cooperation by numerous countries is required to save the Arctic or Antarctic ice, but no initiative is underway toward such an ambitious project. Fortunately, however, Hudson Bay lies entirely within Canada’s borders and this country can keep some of its ice from melting in the summers within five years if the government authorizes a prompt start.

Hudson Bay is a shallow bay of the Arctic Ocean the size of Texas. It is completely covered by ice in the winter but usually all of the sea ice melts between June and August. The white sea ice and snow reflect light and heat, thereby limiting global warning, whereas the open water is dark and absorbs light and heat. Here are satellite photos taken 16 days apart in July 2020.[xvi]

The Arctic is warming at more than three times the average global rate.[xvii] The sea ice is thinner nowadays and the loss of Hudson Bay’s sea ice can affect climate in the southern part Canada too. Moreover, as ocean temperatures rise and the ice melts, the methane clathrate crystals from the bottom of the ocean are released to the atmosphere, increasing global heating even more; as a greenhouse gas measured over a 20-year period, methane is 84-86 times more powerful than carbon dioxide.

Very new research shows that shallow deposits of frozen methane beneath oceans may be more vulnerable to thawing than previously known. Many models predict a warming of 1 to 3 degrees Celsius, which would not thaw the methane hydrates. However, the new research shows how waters at middle level in the ocean could warm up regionally beyond expected average changes. Although projections by the Intergovernmental Panel on Climate Change, do not expect intermediate-depth ocean temperatures to cross the threshold of hydrate instability, the new paleoclimate study deems a very low-probability, high-impact event on hydrate destabilization more likely.[xviii] Given the amount of methane in such Arctic deposits, this release would be catastrophic for life on earth. And, as Bob Berwyn notes,

“such events have happened in the distant past. The trigger for such warming and thawing, according to the study, is a large inflow of fresh, frigid water from melting Arctic ice, which can disrupt the Atlantic Meridional Overturning Current, a slow ocean heat pump, pushing cold water in the Arctic deep down and southward, and warm water to the surface and northward.

“Temperature, density and salinity contrasts drive the pump. But in recent decades, the influx of water from rapidly melting Arctic ice, especially the Greenland Ice Sheet, appears to be weakening the current, which could warm the ocean at depths of 300 to 1,300 meters to destabilize methane hydrates buried 20 to 30 feet deep in the seabed.”[xix]

Arctic ice must be retained in all locations in order to prevent this calamity, and the most sea ice within Canada’s sovereign control is on Hudson Bay, which is already suffering from the loss of it.

In the four provinces and territories bordering Hudson Bay about 39,000 Inuit and First Nations people live in 41 settlements near the shores. The lives and livelihood of Inuit hunters are being endangered by the loss of Hudson Bay sea ice. A survey in 2017 found that more than a third of the adults have no paid employment and fully 85 percent of them depend on the land for their sustenance, regularly hunting, fishing, trapping and gathering wild plants.[xx]

Polar bears in western Hudson Bay are starving. When sea ice breaks up one month earlier than usual, 75 percent of pregnant polar bears will not give birth, so the polar bears may be extinct by 2050.[xxi]

Megan Sheremata, a U of Toronto graduate student who was studying the region, reported that global warming is harming the indigenous population:

“In the more southern areas of the region hunters immediately noticed the ice was more brittle … and some described seeing it literally break behind their snowmobiles. Seals, which normally float when killed in seawater and can be retrieved, were less buoyant in water with reduced salinity, and began sinking out of reach. People say that 15 or 20 years ago, winds of 150 kilometres per hour or more would only occur in the fall. Now you can have windstorms at any time of year. That’s a concern for hunters travelling by snowmobile or boat and also for communities, where high winds can damage buildings and services such as electricity and water supply.”[xxii]

These disasters can be prevented with the following measures, as I learned from Salter and Wadhams, who will gladly contribute their expertise to such a project.

The University of Manitoba has a new and superbly equipped research station, the Churchill Marine Observatory, on Hudson Bay. (See these photos and their website, https://umanitoba.ca/earth-observation-science/facilities-labs-vessels/churchill-marine-observatory.) It would be the ideal headquarters for the operation. In addition, at least one station can be erected in each of the four provinces and possibly on one of the islands. Each such station can simply consist of a shipping container and spray equipment, powered by a wind turbine and monitored by a trained indigenous person.

During the summer, there is more sunshine in the north than at the equator because of the long hours of daylight, and that is when the stations will spray sea water over the Bay, cooling the water and retaining ice that would otherwise melt. Results will be visible from the first season. Some northern regions such as Baffin Bay will also benefit somewhat from the cooling of Hudson Bay.

With about 50 or 60 such stations, it would be possible to save all the Hudson Bay ice, but that would be expensive and take too long. A better investment is Canada’s own partial saving of Hudson Bay ice within five years with only four stations, for this will likely stimulate a larger, international project to save the entire Arctic Ocean with a fleet of about 200 small ships or unmanned drones spraying sea water each summer. Such vessels can be built in the spacious workshop at the Churchill Marine Observatory.

The project can begin right away, though it will probably take three years or so for the nozzles to be ready. Salter is confident he can design and have them manufactured in Britain, where he now runs a company pursuing this idea. In the meantime, the stations can be established, local Inuit personnel trained,[xxiii] and local environments studied more closely. Salter estimates that the entire Canadian project, including the development of the nozzles, requires a budget of C$30 million. It will greatly benefit the inhabitants of the region and make Canada into the world’s leader in solving the climate crisis of the Arctic. Fortunately, if deleterious side effects emerge, the negative effects can be stopped within days.

The preliminary Pugwash investigation should inspect previous research findings and estimate both the financial implications and the potentially negative environmental effects of the project (e.g. the possibility of reducing the rainfall in Africa and Pakistan and/or increasing ozone production).

SOIL: Amend much Canadian agricultural soil by applying mixtures of rock dust, biochar, and seaweed biostimulants.

The most dangerous threats to humankind are inter-dependent as a system. We cannot resolve one without also reducing several others. A conspicuous example of this is the link between the climate crisis and global famine. Extreme weather can defeat farmers, hunters, and fishermen, and bring unemployment, hunger, and migration.

Fortunately, when dealing with a system, we can find interventions that “kill two birds with one stone.” Thus, when we reduce global warming by moving carbon from the atmosphere into soil, the soil becomes fertile again and can feed humankind. This is a win-win solution. We simply need to find optimum ways to move the carbon. Fortunately, two promising approaches are open to Canadians right now to do so simultaneously. These methods involve rocks and trees respectively – in the form of powder and charcoal.

For the first time there is a prospect of worldwide famine. Since 2019 the number of people in the world experiencing food insecurity has risen from 135 million to 345 million.[xxiv] But food is abundant in Canada and indeed, about 40 percent of the food produced in Canada is wasted. There doesn’t seem to be much to worry about here – except perhaps our fertilizer.

The current global food shortage results mainly from the high price of energy and fertilizer. About half of the food in the world could not have been produced without fertilizer; when farmers cannot afford it, their output falls and people go hungry. Russia and Ukraine are the main suppliers and the war has interrupted the exports and raised the prices worldwide. When considering how to feed humankind, we must pay special attention to soil fertility, which of course varies from place to place.

Ironically, Canada’s farms are threatened, not by the lack but the excess of fertilizer. In fact, Canadian soil could yield better and more food without any synthetic fertilizers whatever. Organic and regenerative farmers have proved it and a government report on Canada’s farm soil supports that conclusion. The report describes improvements between 1981 and 2011 and rates Canada’s overall agricultural environment as “good,” though it mentions serious shortcomings: the risk of water contamination from pesticides and the surplus of nitrogen and phosphorus because of the application of fertilizer.[xxv]

Fertilizer is a wicked problem. Half the human population would have starved without it, but it could kill most of us in the long run. The so-called Green Revolution in the second half of the twentieth century brought chemical fertilizers, pesticides, and herbicides to the whole world and made possible the “population boom.” Synthetic fertilizers consist of nitrogen, potassium, phosphorus and “micronutrients,” such as zinc and other metals that are necessary for plant growth.

We’re experiencing the negative effects of these chemicals: the pollution of streams, rivers, ponds, lakes and even coastal areas, as they run off into waterways. There they cause massive algal blooms that sink to the bottom when they die. Their decomposition removes oxygen from the water and creates “dead zones” where fish and other species cannot survive. Humans who eat the diseased fish can themselves become ill.[xxvi]

Regular overuse of chemical fertilizers depletes the soil nutrients and minerals. In addition to eutrophication of waterways, the phosphorus may cause hardening of soil. Soil fertility requires a balanced supply of essential nutrients and minerals, so overuse of specific nutrients may impair the plants’ immune system or disrupt the fungi and other microorganisms that keep soil rich.

When nitrogen is absorbed by soil too quickly; it will dry up the plant. Nitrogen fertilizers contaminate groundwater and can remain in that water for decades. [xxvii] Part of the nitrogen added to soil is emitted into the atmosphere as nitrous oxide (N₂O), a greenhouse gas with global warming potential 265 times higher than that of carbon dioxide. It is the gas most responsible for stratospheric ozone depletion. The agriculture sector is responsible for 66% of gross anthropogenic N₂O emission. Worse yet, by 2050, anthropogenic N₂O emissions are expected to be twice that of today.[xxviii]

For these reasons, agricultural scientists now advocate the replacement of synthetic fertilizers with organic amendments, such as aged animal manure, leaf mold, fish emulsion, blood meal, oyster shells, and compost. All of these are excellent for specific purposes, but wouldn’t it be better to use soil amendments that also capture lots of carbon dioxide from the atmosphere and transfer it into the soil, sequestering it and feeding the roots of the plants that we’ll eat? For those dual purposes we can use biochar and rock dust.

a) Biochar made from trees

Charcoal is made by burning wood or other carbon-containing wastes in the absence of oxygen. Biochar is a synonym for charcoal. In South America there are areas of rich, black soil ten feet deep where Indians buried biochar 7,000 years ago. That charcoal still retains the sequestered carbon.

In land applications biochar can effectively capture three times its applied weight in CO2, measurably adding water-holding capacity.[xxix] And anyone can make biochar from wood as well as other biomass (corncobs, say, old cardboard boxes, or turkey feathers) and bury it, thereby subtracting huge amounts of carbon from the atmosphere and, in most cases, greatly improving the soil (which is degrading globally) and the nutritional quality of the food.

Under an electron microscope, biochar appears to be mostly millions of holes. In fact, because of those holes, biochar is an amazing sponge that will hold huge amounts of water that otherwise would just flow away from the field, eroding some topsoil with it. Moreover, the holes in biochar also are perfect spaces for beneficial soil microbes to live.

Plants prefer soil with a neutral pH of about 6.5 to 7, but many soils now are acid to very acid: 4 to 5.5. In such acidic soils, plants cannot take up nutrients from the soil. But if you add biochar, the pH will rise as much as a whole point higher, making more nutrients available to crops.

Because biochar is so absorbent, every nutrient in the vicinity will stick to it and be released only slowly. That explains the superiority of plants grown in biochar-enriched soil: Nutrients remain more available to them because the biochar keeps the minerals from leaching away too quickly.

Biochar is also good for mycorrhizal fungi, which act as straws for the plants, allowing them to suck nutrients out of inaccessible places in the soil. In return, plants feed the fungi. Overuse of fertilizer breaks this connection because the plants don’t need the fungi, which now must be restored in the soil. Biochar can be filled with nutrients, which will be slowly released in the soil. The fungi will help get these nutrients to the plants. Certain biostimulants (organic fertilizers) will also increase the uptake of these nutrients by the plants. Biochar will also hold onto free phosphorus so that it does not become a pollutant in our freshwater ecosystems.

Chemical or manure fertilizers can guarantee large yields to farmers ­ especially yields of corn, wheat and soy, so farmers need good substitutes for those fertilizers. Though it is not a fertilizer (most of the nitrogen in the wood has escaped during the pyrolysis) biochar solves their problem by holding onto and conserving whatever nitrogen and phosphorus is near.[xxx]

If you drive through the Rocky Mountains, you’ll see hundreds of miles of red forests where the trees have been killed by pine beetles. Most of them will rot and release all their carbon back to the atmosphere, but here is one way to keep that from happening:  Cut the dead trees down, put them in trenches, cover them with soil to keep the oxygen out, and burn them, making biochar and leaving it right there underground. That will sequester a gazillion tonnes of carbon. (Is a gazillion the amount that the tar sands are emitting now?)

But here’s a better plan: Sell the biochar to farmers to enrich their fields. For that, you need pyrolizers to produce the biochar – but that is not difficult. You could just take a dumpster, drill a small hole near the bottom, create a snug lid so the smoke cannot escape and oxygen cannot get in, and voila! – a pyrolizer! You could add some equipment to capture volatile gas that will otherwise escape, but that may not be worth the expense. Any garbage truck could lift your dumpster-pyrolizer and take it to and from the forest. When the wood is baked inside, any lingering pine beetles will be cooked too, and the biochar can be sold or mixed with other amendments such as rock dust for fertilizing soil harmlessly.

How much carbon can biochar remove from the atmosphere? Project Drawdown gives this estimate for the whole world:

“Biochar can reduce carbon dioxide emissions 1.36–3.00 gigatons by 2050. The net cost of implementing the solution would be US$123.54 –244.94 billion, and the lifetime operational cost would be US$333.20–663.11 billion. This analysis draws on total life-cycle assessments of the many ways biochar prevents and sequesters greenhouse gases, while assuming the nascent biochar industry is limited by the availability of biomass feedstocks.”

I think Project Drawdown has underestimated biochar’s potential, for they reassure us that this plan allocates “feedstock to biochar only after demand by all other bio-based solutions has been satisfied.” That is reasonable; we should not turn anything into biochar that might be more useful in other ways. However, Drawdown seems not take account of those millions of dead trees that should be burned anyway if we want to limit the spread of the beetle infestation. In addition, there are plenty of trees in Canadian cities that have been killed by the Emerald Ash Borer.

Indeed, almost every household, small business, and factory regularly produces dry biomass waste that could be made into biochar.[xxxi] When we make biochar from dead wood, we permanently remove carbon from the atmosphere. The biochar that remains is 40 percent of the total carbon contained in the wood – and it will never again enter the atmosphere. For every pound of biochar we make, we remove three pounds of CO2 from the atmosphere.[xxxii]

It is easy to make, so why not enable that? We can set up a few pyrolizers in every neighborhood park (one big one made from a dumpster and a few made from metal barrels) and train a local person to be the “biochar-master.” On Saturdays people can bring woody trash to the park and take home a box of biochar made the previous week to scatter on their gardens. They call that the “circular economy.”

And Canada can use biochar on an even larger scale by using it, mixed with other amendments, to substitute for the harmful synthetic fertilizers that are otherwise essential to the productivity of our agriculture. A uniquely promising component of the mixture is rock dust.

b) Rock Dust Carbon Sequestration

Why is Earth cooler than Venus? According to Google, Venus is surrounded by CO2, so temperatures reach 462 degrees Celsius there.  But we Earthians can thank our Mother Earth, who removes carbon from the atmosphere by eroding rocks. For this, Mama uses rain, which becomes carbonic acid (much weaker than sparkling water) as it contacts CO2 in the air. When this weak carbonic acid falls on certain rocks, including basalt and olivine, a chemical reaction occurs, producing bicarbonate and cations. Cations are transferred into the plants and the soil. If the soil lacks cations, then eventually that carbon will just escape back into the atmosphere. It’s the cations that keep dissolved carbon dioxide (bicarbonate) in the water until it flows into the ocean, where eventually it becomes sediment at the bottom. It remains there for millions of years, until perhaps turned over by a tectonic plate upheaval and eventually spewed out as lava again from a volcano. The cycle continues.

We can speed up nature’s method by pulverizing the rocks; the more surface area a rock has, the more CO2 it can capture, so we grind the rock into powder, which has far more surface area than a stone. When farm soil is sprinkled with the rock powder, it absorbs CO2 and the microbes make the minerals into nutrients, including nitrogen, which regenerates the fertility of degraded soil.[xxxiii] So, soil treated with rock dust does not require chemical fertilizers. And, since agriculture accounts for nearly a quarter of the world’s carbon dioxide emissions, Canadian farmers can help solve global warming and hunger simultaneously.

On a large scale, that process, nowadays called “enhanced rock weathering,” can capture vast amounts of the carbon dioxide from the atmosphere and lock it up for hundreds of thousands of years. The powdered rock absorbs two to four tons of atmospheric carbon dioxide per hectare over the course of five years.[xxxiv]

We are interested in rock dust for dual purposes: (a) to enhance the productivity of the soil and (b) to remove carbon from the atmosphere and cool our planet. But does it really improve soil? And does it sequester carbon?

First: Yes, as a soil amendment it does enhance fertility, eliminating the need for chemical fertilizers. The research that I have found give consistently favorable reports, noting that rock dust contains micronutrients and trace elements that enable beneficial microbes to flourish and contribute to the life cycle of plants. No report mentions any harmful effects.

There are improvements in plant structure, increases in resistance to pests and disease, and more flavorful vegetables. Rock dust does all this with its minerals and trace elements, such as calcium, iron and manganese, which are difficult to replace after being depleted from the soil. It releases these elements when interacting with soil microorganisms and plant material. According to Yale Environment, “Field tests on corn and alfalfa show increases in crop yields; the rock dust releases other essential nutrients, including phosphorous and potassium.” Some yields are 30 percent higher. Remineralization with rock dust is a low-cost, high-impact way to produce healthier people and a healthier planet.[xxxv]

Second: Yes, rock dust does remove carbon from the air.  According to the U.N. Intergovernmental Panel on Climate Change (IPCC), rocks naturally remove one billion tons of carbon dioxide a year from the atmosphere. Rock dust could theoretically, if applied to croplands around the world, remove two to four billion tons of carbon dioxide from the air every year. That amount is between 34 percent and 68 percent of the global greenhouse gas emissions produced by agriculture annually.[xxxvi]

The most frequently cited study of rock dust’s carbon removal value, by David Beerling et al, compares the carbon removal potential and costs among nations in relation to business-as-usual energy policies and policies consistent with limiting future warming to 2 degrees Celsius. These researchers assert that

“China, India, the USA and Brazil have great potential to help achieve average global CDR goals of 0.5 to 2 gigatonnes of carbon dioxide (CO₂) per year with extraction costs of approximately US$80–180 per tonne of CO₂. These goals and costs are robust, regardless of future energy policies. Deployment within existing croplands offers opportunities to align agriculture and climate policy. However, success will depend upon overcoming political and social inertia to develop regulatory and incentive frameworks.”[xxxvii]

Other papers seem to support the same conclusion, including one by Johannes Lehmann that declares, “It now seems that this approach is as promising as other strategies, in terms of cost and CO₂-removal potential.”[xxxviii]

For every ten tons of rock applied to Canadian fields, one ton of  CO2 will be locked away. Globally, rock dust now permanently locks away between two and four million tons of atmospheric carbon per hectare over a five-year period.[xxxix] Let’s average it at three million tons when estimating how much Canadian farms might sequester. In 2016 Canada had 93.4 million acres (37.4 million hectares) of cropland. If rock dust were applied to all of that Canadian land, it would remove 112 million tons of carbon over a five-year period.

That sounds impressive, but according to Google, Canadian agricultural activities (minus fossil fuel use) emit 50 million tonnes of CO2 per year — or 250 million tonnes over that five-year period. So, that 112-million-ton reduction is only 45 percent as much as agriculture emits — and even that is overly hopeful, since we cannot really expect every farm in Canada to spread rock dust. Half of them may be an optimistic guess. (A tonne is a little more than a ton.)

But to make the estimate fair, we should subtract the amount of carbon emitted by the processes of grinding, transporting, and spreading the rock dust. The amount will vary, but we must reduce the estimate by 10-20 percent in some cases. It is generally costly transport rock dust, but long-distance rail shipments are affordable. Fortunately, however, the aggregate industry already produces powdered rock as a by-product, so plenty of rock dust is already available, often nearby.[xl] So, let’s set a realistic goal for Canada: to remove 50 million tons of CO2 from the atmosphere over a five-year period by spreading rock dust.

Mine tailings are cheaper than newly ground basalt and can cost as little as $15 per tonne of carbon removed. David Demarey, a Massachusetts farmer and chemical engineer, is even more enthusiastic about Black Lime, an ordovician shale that can be obtained in Vermont about ten miles from the Canadian border. Demarey has produced some useful estimates for me:

“I looked at the offsets to the cost of applying the Black Lime to agricultural soils in commercial quantities of one to eleven tons per acre. The tonnage isn’t entirely critical to the analysis because piling on more of it at one time does not multiply the beneficial effect beyond a certain baseline. The number of tons per acre does have a bearing on the rate and quantity of carbon dioxide that can be sequestered into the soil.

“The analysis is complex and therefore I will only summarize the results for now:

“The Black Lime generates about twice its cost in benefit to agricultural yield, trace element supply, limestone equivalence (The Black Lime has significant carbonate) and interestingly, carbon capture.

“I predicated the valuation using conservative values of:

“Trace Element sources at $3.5 per pound 

“Limestone Equivalence at $37/ton for lime.

“Enhanced crop yield of 7%.

“Carbon Capture Equivalence at $150/ton CO2.

“It is clear that these estimations are on the very low end of what is possible, but the literature has numerous examples near these values. 

“Carbon capture averages around one tenth ton CO2 per ton of Black rock – or ten tons of rock to capture a ton of CO2.

This is somewhat lower than some basalt types, but the Black Rock carries a higher and more uniform array of trace metals as well as significant short-term alkalinity, both of which matter in agricultural soils.

“In short, Black Lime or similar rock dusts can be applied to soil at no net cost for the application but still achieve carbon capture. No other material, biochar included, can make that claim.

“Biochar can be combined with rock dust to lower the number of tons needed to achieve one ton of carbon dioxide absorption but the costs of doing this climb as you increase the amount of biochar. You trade cost/profit for quantity of application. The analysis predicts a zero point in cost/profit at around 30% biochar.”

Thomas Vanacore[xli] told me that the Black Lime also manages phosphorus. His team demonstrated cost effective potentials for use of the Black Lime (with and without biochar) on land and also for engineered applications to control point source phosphorus in wastewater and fish hatcheries.

As Demarey notes, far better results occur when biochar and rock dust are combined. Nowadays, some biochar producers are enriching the biomass by adding rock dust before the pyrolysis. This reduces carbon loss during pyrolysis, thereby reducing the cost of CO2 removal by 17 percent to US$ 80–150 t−1 CO2, with as much as 30 percent savings at higher biomass costs.[xlii] Also, if the rock dust is rich with potassium, the process makes available more of it and phosphorus. Thus, the combination of rock dust with biochar makes the addition of chemical fertilizers unnecessary, though organic fertilizers are beneficial – especially seaweed.

Fortunately, I met a group of rock dust experts who had already been working together to develop a mixture of biochar, rock dust, and seaweed. Seaweed actually captures more carbon from the atmosphere than trees do but it does not long sequester carbon, for it decomposes in the soil, returning its carbon to the atmosphere. However, it is an excellent amendment to stimulate plant growth, as I learned from the group. David Demarey introduced me to the foremost rock dust expert Thomas Vanacore, who introduced me to longtime biochar expert Tadeusz Wysocki, Halifax seaweed expert John Sewuster, and Ontario agronomist Ryan Brophy. They all participated in one of my talk shows, available as https:tosavetheworld.ca/episode-497-rocks-biochar-seaweed.

I was surprised to learn that Brophy owns a company called “V6 Agronomy,” which has received approximately 14,000 tons of basalt rock dust in Saskatchewan and Ontario via rail transport from the US as well as several truckloads and rail car shipments of the Black Lime.  He has initial support from the Canadian Development Bank to build a fertilizer compounding facility in Eastern Ontario which will integrate rock dust and biomass at scale. That compound is immediately available for use by Canadian farmers, if the government responds favorably to the Pugwash proposal and subsidizes the first adopters.

Vanacore is the leader in this group, which recently has been using seaweed and seaweed extracts as plant biostimulants. They had already used the raw plant in feed, food and soil amendment applications for many years. He and Sewuster hope to develop the seaweed supplies of kelp farms along the shorelines.

I was surprised to learn that kelp forests are now flourishing in Hudson Bay, even as they are disappearing in western Australia, northern California, and the coastline of North America. Cool water species can survive freezing, long periods of darkness, and even grow under sea ice. Possibly the Inuit communities around Hudson Bay could supplement their income by harvesting some of these seaweeds, drying them on rocks (as practiced in Asia), and shipping them by rail from Churchill to be added to the rock dust-biochar mixture and applied to crops in Manitoba and Saskatchewan.

Many farms worldwide are already equipped for adding rock dust to soils (their fertilizer-spreading equipment serves that purpose equally well) so it is entirely feasible for Canadian farms to adopt the practice immediately if the financial incentives are attractive.[xliii] Already scientists are spreading basalt on cornfields in Illinois and on sugarcane in Australia. In Ontario, researchers are applying wollastonite from a nearby mine on soybean and alfalfa fields.

Despite all the aforementioned advantages, the Canadian government has given more support to mechanical inventions for capturing and sequestering carbon.[xliv] This irks some experts, such as Professor Willem Langenberg, who concluded his presentation comparing the two approaches with this exhortation:

“The reduction of 363 MT of CO2 emission per year for Canada by 2030 is difficult to achieve. Reaching the goal of zero emissions by 2050 is even more difficult. To rely on only one means of reducing emissions, and one that has not been proven to be reliable, safe, and cost-effective, is shortsighted. For these reasons, Canada needs to increase funding for research on other processes that are more efficient, effective, and financially viable, such as the uptake of CO2 by vegetation, soils, and water, and the natural geological processes of CO2 capture by weathering (mineral carbonation).”[xlv]

Government financial support may be required to incentivize the adoption of this innovation within two years. However, the first adopter farmers will soon find the innovation highly profitable. Their real payoff will come when they sell their product. The rock dust-biochar-seaweed mixture will pay for itself over and over again. The payoff for Canadians will be a cooler planet and more abundant and nutritious food.

Yet the changing climate means that it is urgently necessary to familiarize Canadians with the possibilities of these soil amendments. The Pugwash report may propose to the government two possible ways of promoting the change. The first, and probably best, way is to subsidize the first use of the compounds. However, parliament might find the second approach simpler: enact legislation requiring all fertilizers sold in Canada to contain minimum specified proportions of rock dust, biochar, and seaweed.

 APPENDIX

LINKS TO A FEW SELECTED PROJECT SAVE THE WORLD TALK SHOW VIDEOS

1. Plant trees in lawns, roadsides, parking spots

https://tosavetheworld.ca/49-can-drones-plant-a-trillion-trees/

https://tosavetheworld.ca/80-miyawaki-forests/

https://tosavetheworld.ca/86-arctic-permafrost-and-trees/

https://projectsavetheworld.libsyn.com/328-urban-trees-and-climate

2. Use carbon-negative concrete in all government-funded projects

https://tosavetheworld.ca/episode-383-making-carbon-negative-concrete/

3. Brighten Canadian Arctic clouds

https://tosavetheworld.ca/103-arctic-changes/

https://tosavetheworld.ca/185-the-methane-threat/

https://tosavetheworld.ca/episode-434-help-the-ice-is-melting

https://tosavetheworld.ca/272-brighten-the-clouds/

https://tosavetheworld.ca/episode-374-saving-the-corals/

4. Improve soil by sequestering carbon with rock dust and biochar.

https://tosavetheworld.ca/123-the-carbon-underground/

https://tosavetheworld.ca/358-why-you-need-a-market-for-biochar/#video

https://tosavetheworld.ca/367-your-food-and-things-that-fall-from-the-sky/

https://tosavetheworld.ca/355-fertilizer/

https://tosavetheworld.ca/episode-497-rocks-biochar-seawee