Land Based Solutions
Land based solutions to the climate crisis include methods to use natural processes (aka Natural Carbon Capture) and resources to remove CO2 from the atmosphere. This includes Regenerative Agriculture practices and techniques, the closely related Healthy Soil principles, and reforestation and afforestation. Enhanced mineral weathering uses naturally occurring minerals that when ground can absorb CO2 from the atmosphere when spread on farms and ranches. This approach is sometimes referred to as 'Negative CO2 Emissions'. By comparison, Artificial Carbon Capture uses developing technologies to remove CO2 from the atmosphere.
IPCC Report on Climate Change and Land
The IPCC Special Report on Climate Change and Land addresses greenhouse gas (GHG) fluxes in land-based ecosystems, land use and sustainable land management in relation to climate change adaptation and mitigation, desertification, land degradation and food security. Chapter headings are:
- Summary for Policy Makers
- Technical Summary
- Framing and Context
- Land–Climate interactions
- Land Degradation
- Food Security
- Interlinkages between desertification, land degradation, food security and GHG fluxes: synergies, trade-offs and integrated response options
- Risk management and decision making in relation to sustainable development
(aka Regenerative Farming, Regenerative Annual Cropping)
From Project Drawdown:
Regenerative agricultural practices include:
- no tillage,
- diverse cover crops,
- in-farm fertility (no external nutrients),
- no pesticides or synthetic fertilizers, and
- multiple crop rotations.
Together, these practices increase carbon-rich soil organic matter. The result: vital microbes proliferate, roots go deeper, nutrient uptake improves, water retention increases, plants are more pest resistant, and soil fertility compounds. Farms are seeing soil carbon levels rise from a baseline of 1 to 2 percent up to 5 to 8 percent over ten or more years, which can add up to 25 to 60 tons of carbon per acre.
It is estimated that at least 50 percent of the carbon in the earth’s soils has been released into the atmosphere over the past centuries. Bringing that carbon back home through regenerative agriculture is one of the greatest opportunities to address human and climate health, along with the financial well-being of farmers.
Regenerative Agriculture is a system of farming including healthy soil principles and practices that increases biodiversity, enriches soils, improves watersheds, and enhances ecosystem services. Regenerative Agriculture aims to capture carbon in soil and aboveground biomass, reversing current global trends of atmospheric accumulation and loss of healthy soils. Irrigations demands are also improved with the improved water retention arising from improved soil quality.
- "Regenerative Agriculture: Solid Principles, Extraordinary Claims" - Washington State University - April 4, 2018 - a discussion
A component of Regenerative Agriculture is the practice of composting. Dr. David C. Johnson, molecular biologist and research scientist at the New Mexico State University has developed a system that brings lifeless soils back to life by reintroducing beneficial microorganisms to the soil with biologically enhanced compost from a 'bioreactor'.
Regenerative agriculture has met with success as documented in these project videos:
- "The Story of Al Baydha: A Regenerative Agriculture in the Saudi Desert" YouTube Video (19:47)
- Akira Miyawaki-type of mini forest In Holland: "Tiny Forest by IVN, Netherlands" YouTube Video (9:55)
The importance of regeneration in semi-arid regions is reported:
- "Climate model simulations suggest that planting large-scale semi-arid forests could cool the planet"
Closely allied or even part of Regenerative Agriculture, Regenerative Grazing practices using remote sensing technologies have been shown to improve ranch economics.
Conclusions from the study included:
- "The upside is that bare ground declined while cover, forage, beef production and habitat improved. Tom Sidwell explained that the resultant higher forage production, higher average stocking rate and more calves to sell – plus planning for drought and innovative marketing – means ranch revenue is better and more dependable than ever. Equally important, the increased cover and soil carbon initiated a positive cascade – capturing more water, reducing runoff, increasing forage production and lengthening the ‘green’ period – good for livestock, wildlife and the bottom line."
Healthy Soil Principles
An integral part of Regenerative Agriculture, healthy soil principles have been identified by farmers and scientists. While coming more from a farming perspective, these concepts apply similarly to rangelands, urban farming and victory gardens. The principles work in every ecosystem, on every scale, and foster a more holistic approach.
1. Keep soil covered
In nature, bare soil is an anomaly. Soil cover is critical to protect soil from wind and water erosion, provide food and habitat for macro- and microorganisms, and to prevent moisture evaporation and germination of weed seeds in farm fields. The best way to keep soil covered is to grow a dense and diverse carpet of plants or grasses, offering microbes both food and shelter. Protecting soil with a layer of mulch or litter holds in moisture, buffers soil temperature, cuts down on evaporation and makes the most out of New Mexico’s scarce water resources.
2. Minimize soil disturbance on cropland & minimize external inputs
Tilling, chemical fertilizers, herbicides and pesticides harm the web of life in the soil and should be avoided as much as possible. Alternatively, compost boosts soil health, promoting stronger plants and resilience towards disease, and supporting microbes that feed directly on parasites.
3. Maximize biodiversity
Greater diversity above and below the ground creates more resilient and productive working lands. Each plant, insect or animal has something different to offer and each of them plays a role in maintaining soil health. Together they provide a varied diet for soil microorganisms, with additional benefits such as breaking of disease cycles and creation of habitat for wildlife and pollinators. Nature does not know monocultures, instead diversity enhances ecosystem function.
4. Maintain living roots
Soil organisms cluster around roots, where they exchange nutrients with plants. Those living roots provide their basic food source: carbon. In turn, the soil biology fuels the plant nutrient cycle. Encouraging a variety of warm and cool season grasses through planned grazing, replacing annuals with perennials, or planting multi-species cover crops are some of the strategies to ensure continuous roots year-round.
5. Integrate animals
A healthy farm ecosystem provides habitat for animals large and small, including pollinators, earthworms, and all of the soil microbiology. Planned grazing, which mimics migratory herds of ungulates, is essential for soil health on rangeland: animals are moved quickly through pastures in one compact herd, giving grasses adequate time to recover in between grazing periods. Animals can also be used to graze cover crops or post harvest. Hedgerows or pollinator strips provide food and habitat for beneficial insects and earthworms thrive in healthy soil.
New Mexico has a number of agricultural examples on how to apply the Healthy Soil Principles.
Bioenergy with carbon capture and storage
Bioenergy with carbon capture and storage – better known by the acronym “BECCS” – may be one of the more viable and cost-effective negative emissions technologies. There are many attractive features, since this technology could provide energy – thus reducing our need for fossil fuels – and remove CO2 from the atmosphere at the same time.
However, the full carbon-cycle impacts of large-scale deployment of BECCS are not well studied. No studies have looked at these impacts specifically for a scenario that could meet the 1.5°C target.
- "Why BECCS might not produce ‘negative’ emissions after all" - Carbon Brief - Dr. Anna Harper - August 14, 2018
Reforestation and Afforestation
From Nature4Climate website...
Afforestation (growing new forests) and reforestation (restoring existing forests), combined with a variety of land management and conservation practices, could remove around 1-2bn tonnes of carbon from the atmosphere per year. There is a potential warming effect of forests as well, especially in high-latitude areas where adding trees can warm the climate since their albedo is lower than snowy ground or agricultural land.
Around the world, huge swaths of temperate and tropical forests have been cleared for human activity. Many of those lands are being used productively to grow food and raise livestock that we need and, with yet better practices, can sustainably yield even more food. Yet many other deforested lands are degraded, produce less than one cow per hectare, and are good candidates for reforestation.
- "Reforestation" - Nature for Climate
Enhanced Rock Weathering & Mineralization
Still under development, some processes add minerals to the seas, others distribute dust on the land:
- "Removal of atmospheric CO2 by rock weathering holds promise for mitigating climate change" - Nature - July 8, 2020
- "Enhanced Weathering for Carbon Capture" - Earth.org - February 2020
- "CO2 Removal With Enhanced Weathering and Ocean Alkalinity Enhancement: Potential Risks and Co-benefits for Marine Pelagic Ecosystems" - Frontiers in Climate - October 2019
- "Enhanced Weathering" - The Azimuth Project - undated - includes some chemistry
For an in depth review of mineralization processes to capture CO2 see this report from the American Association for the Advancement of Science:
- "Industrial waste can turn planet-warming carbon dioxide into stone" - AAAS - September 3, 2020