While switching from fossil to renewables is needed for ecological, economic, and health reasons, it is no longer sufficient to stabilize the global climate, as our best scientists have repeatedly been telling us. What is required now is a direct, rapid, massive, effective, timely, verifiable and sustained carbon dioxide removal (“CDR”). Whether that is viewed as economically beneficial or detrimental depends largely on whether you are still using the economics of an earlier century or the New Climate Math.
Composing a power-point en route to the GEN-Europe meeting in Italy last month, I fashioned a slide that went something like, “Pakistan held the record for most trees planted in a single day—847,275—set in 2013 until India planted 49.3 million in one day in 2016.” India then raised their own record to 66 million in 2017. “Isn’t it time that record was broken again?” I asked.
But, by the time I got to Italy, Ethiopia had smashed India’s record with 353,633,660 tree seedlings transplanted in 12 hours. Their national pride at stake, one million Indians turned out on August 11 and put 220 million trees in the ground, a personal best, but not a new world record.
Ethiopia's goal is one billion trees and they are on track to reach that. Ethiopians don’t just produce great marathon runners. They also sprint.
I proposed to my audiences in Europe that there be a new tree planting Olympics. Wouldn’t it be great if on one day each year, or one week every four years, all nations vied to set a new world record?
In 2017, Frank Michael and I prepared a presentation at the 7th World Congress of the Society for Ecological Restoration in Foz do Iguassu, Brazil, that we called Climate Ecoforestry, in which we examined some of the main questions that come up around tree planting. Frank passed away before the conference and the trip was canceled, but here are some of our results, in Q&A format:
How many trees need to be planted to restore the atmosphere to safe concentrations of greenhouse gases?
Several trillion. The precise number will vary by region because of seasonal variation, growing conditions, and rotation potentials. Please keep in mind that most of the long-lived greenhouse gases sent skyward during the industrial era have been absorbed by the ocean, which remains in approximate equilibrium with concentrations of carbon dioxide in the atmosphere. Any attempt to thin the atmosphere of carbon dioxide will be met by ocean off-gassing, so it is necessary to approximately double the number of trees planted to achieve a specific desired drawdown. If we wish to remove all the legacy fossil-origin carbon in the atmosphere (approximately 350 gigatons), we would need to withdraw 700 gigatons.
How much land would that require?
There is no shortage of area for planting. After the last Ice Age, there were 6 trillion trees on Earth. Now there are 3 trillion. Putting those lost forests back into the landscape will be difficult in some areas that have since become degraded or desertified. Nonetheless, there are at least 1.5 billion hectares, about two Canadas or one Russia, that are already available, with suitable fertility and water, without impinging on existing farms or neighborhoods. Another 1.5 billion hectares can be added by carbon farming, integrated agroforestry, silvopasture, and greening the desert, and likely more than that could come from marine permaculture—harvesting seaweed and algae.
How quickly could that be done?
Withdrawing 700 gigatons of carbon from the atmosphere could be accomplished by as early as mid-century, assuming we stop adding more. It does no good to try to remove carbon with one hand if the other hand keeps adding it (at a steadily accelerating rate).
The United Nations Food and Agriculture Organization (FAO) defines "climate-smart agriculture" as "agriculture that sustainably increases productivity, resilience (adaptation), reduces/removes greenhouse gases (mitigation), and enhances the achievement of national food security and development goals." Our prescriptive model shows that if Climate Ecoforestry were implemented at the rates of 200-300 Mha/yr (five Spains per year) over an eventual area of 4.8 Gha (5 Brazils), it could store all current anthropogenic emissions, and achieve the goal of restoring pre-industrial CO2 atmospheric levels, while supplying many other benefits to humanity and the natural environment. It would operate over a long enough period to allow an orderly shift of financial assets to renewable energy generation, storage, and new carbon economy infrastructure development.
By addressing the social inertia component of the problem we can enter upon a virtuous cycle of solutioneering that might enable us to go beyond mere survival. Stabilizing the climate and regreening the planet could redirect the role of humans from top polluters and predators to instead become protectors, partners, and stewards.
What would need to be done after the planting to assure the result is as we want?
It is in the establishment phase, dominated by young plants, that plant ecosystems sequester the most carbon. This is one reason some, like the Savory Institute, argue for rotationally grazed grasslands—they essentially remain juvenile and continue along at peak sequestration. But the same can be accomplished, to greater effect, with managed forests, in a pattern Frank termed “step-harvest,” a part of our Climate Ecoforestry strategy. That strategy also recommends:
- Use naturally-charged biochar soil plugs to grow mixed-species seedlings. Add biochar to the soil at the root level when planting saplings in the field.
- Include sun-loving, fast-growing, and water-pump taproot pioneer species saplings, spaced to shade and protect other saplings.
- Patch harvests will consist of non-surviving saplings first, and poorly-thriving trees next.
- Trees clustered in beneficial microbiomes will be identified and protected, and the mother trees will be preserved.
- Biochar manufacture will take no more than 50% of the harvested biomass.
- Forest products will have limits that depend on a) the biome's productivity; b) the climate requirements; c) the health of the stand; d) the amount of disturbance that logging would inflict on the ecology; and e) a 100-year embodied carbon standard for lumber use or furniture design.
At its essence, ecoforestry envisions a systemic blending of humans with natural systems that can include forest product biorefineries, biochar production and use, ecovillages, and fulfillment of most of the 17 Sustainable Development Goals. But let me go back to the point about step harvest first because it not only keeps the largest sequestration engine—mixed-age, mixed species forest ecosystems—running at top speed, it also provides the financial underpinning to make the whole system attractive enough to get buy-in at the grassroots.
A step-harvest system functions much in the same way the traditional milpa system developed by indigenous peoples does: a patch of forest is cleared and widely diverse new growth springs up or is densely planted. In a natural system it may be birds and wandering mammals doing the planting or in a cultivated area it may be farmers, but the result is similar. As the canopy begins to close, layers of dappled light form and some individual plants may be thinned out to benefit others. These thinnings, if left on the forest floor, would release greenhouse gases. Instead, humans can intervene and use those thinnings to produce value-added products—leaf protein; bio-oils; roundwood; lumber; and biochar, for instance (the number of products is limited only by the imagination). Making biochar also co-produces energy and oils and the carbon takes on a hard, almost mineral form that will not decompose quickly—on the order of centuries to millennia. Having biochar as part of the cycle preserves your gains, like cashing in after you have just won a large poker pot and thereafter hazarding only a small portion of your winnings.
The tree-planting cycle can in principle be repeated indefinitely by beginning again on the same land, harvesting the oldest trees, and densely replanting saplings in the same forest cells with biochar-amended soil. Also, relatively marginal land can be restored, allowing mixed-use forest expansion into previously unsuitable territories.
Because these step-harvest/biorefinery systems benefit rural communities, essentially creating microenterprise hubs, it is thought that large numbers of people will mobilize and allow more parts of their landholdings and more populated areas to host trees. The city of Stockholm, Sweden is a good example of this. By mid-century we could reach the required 4.8 billion hectares (6 times the area of Brazil) needed by our estimate to restore pre-industrial equilibrium.
What are the big unknowns?
After a few more decades of business-as-usual, extreme climate volatility could make forestry and agriculture difficult and no longer cost-effective over large regions of the world [Solomon et al. 2011]. Furthermore, at the current atmospheric CO2 concentration of over 415 ppm, the planet has passed a threshold into a region in which a methane-emissions-driven runaway climate is more likely, and where even more severe amplifying climate feedbacks are possible. One example is the giant seaweed bloom now forming off of Africa and Brazil, which, as that material decays, will send massive plumes of methane and other greenhouse gases to the atmosphere. Another example is the gigantic release of methane from melting permafrost, now running decades ahead of schedule.
Trees and the natural understory form microbiomes of mutual support and reciprocity. In desert or mountainous regions, the more severe the environment, the smaller the microbiomes, but these tree and plant communities have shown much greater resilience to all kinds of stresses.
It should also be noted that while we now have four centuries of experience warming the planet, we have almost no experience cooling it (although two historic examples have been described here before). Large unknowns are lurking in our best calculations.
The model is unable to predict uncertainties that may propagate through global resource depletion, financial collapses, wars, and human population expansions, especially in vulnerable regions. Climate Ecoforestry's benefits could be nullified, for instance, if the world's population continues to grow at present rates. More people require more food and more land, adding to the burden.
How would all of this be paid for?
Financial returns for planters, managers, and landholders are obtained by selective harvest in regularized steps. Forests are managed by holistic, regenerative design. The periodicity of step-harvests is a function of growth rates of the various species, local conditions, and climate. So, for instance, fast-growing Bambuseae such as Phyllostachys aureasulcata will double in biomass annually in both temperate and tropical climates within a range of known latitudes and elevations [Hidalgo 2003]. Plantations can take 3 to 5 years to establish before harvest commences, and then harvest is regulated to neither harm the grove nor hinder grove expansion if expansion is desired. A harvest of, for instance, 30 percent of the grove — the oldest culms — would be sustainable if soil fertility is replenished as the method contemplates.
A second example would be a hardwood temperate forest, seeded with diverse species, including those that favor ground cover and understory. Depending on seeding density, the canopy may take 1- 20 years to close, but in the interim, poorly developing, thickly sown, and less desirable varieties can be removed at regular intervals, opening space and increasing nutrient flows for the more desired varieties and diversities. The biomass being removed annually is approximately the same each year following establishment. At full maturity, the forest can either be left alone to continue its somewhat slower sequestration work, or it can be “patch harvested” and reseeded to recover its high juvenile growth rate.
Agroforestry provides many useful products and services to modern economies but is often outcompeted in the marketplace by other methods of production. It can financially succeed or fail based on site selection, local markets, and other factors that raise or lower risks. [Haugh 2006] To reach the global scale of response required by the pace of climate change may require added entrepreneurial incentives. Biochar can supply many of these.
Biochar can be used as a carbon fertilizer; a compensatory fertilizer for trace elements; a compost accelerator; a substitute for peat or vermiculite in potting soil; a silage moderator; a feed additive/digestive supplement; a robiotic/nutriceutical; a litter additive; a slurry treatment; for manure composting; for water treatment in fish farming; as insulation; for air decontamination; for decontamination of earth; as humidity regulation; as dust and pollen scrubber; as electromagnetic radiation screen; as a barrier preventing pesticides getting into surface water; for oil spill remediation; for biogas slurry treatment; as active carbon filter for smoke and exhaust; as pre-rinse additive; as a media for composting toilets; for carbon fiber; for electronic semiconductors; for batteries; for metal reduction; for alloys; for cosmetics; for soaps; for skin-cream; for therapeutic bath additives; for paints and stains; for food colorants; for energy pellets; for poisoning control; for detoxification; as a carrier for active biopharmaceuticals; for functional deodorant underwear, socks, shoes and fabrics; for thermal insulation for clothing; for filling for mattresses and pillows; in cement, concrete, asphalt and steel; and as an avenue for greenhouse gas mitigation. [Schmidt 2014]
In each of these transformations of forest products reside opportunities for microenterprise. Merely managing a forest for carbon sequestration would not provide adequate returns to attract investment of capital or labor. By cascading forest products, the system can finance itself without the imposition of regulatory incentives and disincentives or by the diversion of funds from other sources.
The startup phase of tree-planting requires that a modest quantity of biochar (~5 ton/ha) be made available for the initial plantings. After the first three step-harvests in years 1-4, the projects generate their own biochar for forestry, plus a considerable surplus for agricultural use.
What odds do you give that we will actually do this?
About one percent.
And if we don’t?
We will all die.
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