Negative emissions represent a process removing carbon dioxide (CO₂) from the atmosphere and its permanent storage in natural or artificial reservoirs. In other words, these are negative greenhouse gas emissions that reduce the total amount of CO₂ in the atmosphere, as opposed to regular emissions that increase it.

The importance of negative emissions

– Limiting global warming: According to the Paris Agreement, the goal is to keep the increase in global average temperature well below 2°C above pre-industrial levels and to pursue efforts to limit it to 1.5°C. To achieve this goal, it is necessary not only to reduce emissions, but also to remove CO₂ that has already been released into the atmosphere.

– Compensation of unavoidable emissions: Some sectors, such as aviation or industrial processes, may have difficulty reducing emissions to zero completely. Negative emissions can help offset these unavoidable emissions.

– Reversing climate change: Removing CO₂ from the atmosphere can help mitigate or reverse some of the impacts of climate change and stabilize the climate system.

Technologies enabling negative emissions

Negative emissions can be achieved through a variety of natural and technological solutions. These methods focus on: carbon sequestration – its capture and permanent storage.

---

Nature-Based Solutions

1. Afforestation and forest restoration

– Description: Planting new trees and restoring degraded forests.

– Mechanism: Trees absorb CO₂ during photosynthesis and store carbon in biomass and soil.

– Benefits: Lower costs, improved biodiversity, ecosystem services and soil quality.

– Limitations: Need for large areas of land, risk of carbon release in fires or deforestation.

2. Agroforestry

– Description: Combining agriculture and forestry by growing trees on agricultural land.

– Mechanism: Trees in fields increase carbon sequestration and provide shade and protection to the soil.

– Benefits: Increases soil productivity, resilience to climate change and biodiversity.

3. Restoration of wetlands and peatlands

– Description: Protection and restoration of ecosystems rich in organic carbon.

– Mechanism: Wetlands and peatlands store large amounts of carbon in the soil below the water table.

– Benefits: Improves water quality, biodiversity and provides flood protection.

– Limitations: Sensitive to changes in water management, potential methane release.

4. Soil carbon sequestration

– Description: Implementing agricultural practices that increase soil organic carbon content.

– Mechanism: Conservation tillage, cover crops, and crop rotation improve carbon accumulation.

– Benefits: Improved soil fertility, water retention and erosion resistance.

– Limitations: Potential carbon saturation of soil, need for long-term maintenance of practices.

---

Technological solutions

1. Bioenergy with carbon capture and storage (BECCS)

Description: Combination of biomass energy production with technologies for capturing and storing emitted CO₂.

– Mechanism: Energy is produced by burning biomass; the released CO₂ is captured and stored underground.

– Benefits: Generating renewable energy while removing CO₂ from the atmosphere.

– Limitations: Need for large areas for biomass cultivation, competition with food production, high costs.

2. Direct Air Capture (DAC)

– Description: Technologies that remove CO₂ directly from the atmosphere using chemical processes.

– Mechanism: Air passes through filters or sorbents that bind CO₂; then the CO₂ is released and stored.

– Advantages: Can be placed anywhere, does not require large areas of land.

– Limitations: High energy requirements, technology and infrastructure costs.

3. Mineral carbonation

– Description: The process by which CO₂ reacts with certain minerals to form stable carbonates.

– Mechanism: Acceleration of natural weathering of rocks, thereby permanently depositing carbon compounds.

– Advantages: Long-term and stable carbon storage.

– Limitations: Need to extract and transport large volumes of rocks, energy consumption.

4. Biochar

– Description: Production of carbonaceous material (biochar) by pyrolysis of biomass and its application to soil.

– Mechanism: Biochar stably stores carbon in the soil and improves its properties.

– Benefits: Improved soil quality, increased crop yields, long-term carbon storage.

– Limitations: Limited availability of biomass, need for distribution and application solutions.

5. Ocean alkalinization

– Description: Adding alkaline substances to the oceans to increase their ability to absorb CO₂.

– Mechanism: Chemical changes in seawater lead to an increase in CO₂ solubility.

– Advantages: Great carbon storage potential.

– Limitations: Insufficiently researched ecological impacts, technical and logistical challenges.

---

Challenges and considerations when implementing negative emissions

– Costs and financing: Many technologies are financially demanding and require investment in research and development.

– Energy intensity: Some methods, such as DAC, require a large amount of energy, which may affect their overall benefit.

– Social and environmental impacts: Potential competition with the food industry, impact on biodiversity, need to consider ethical aspects.

– Technological limitations: Some technologies are still in the early stages of development and require further research.

– Political and public support: Successful implementation depends on regulations, incentives and societal acceptance.

Negative emissions are an important part of global efforts to reducing the concentration of CO₂ in the atmosphere and limiting global warming. Combining natural and technological solutions can help achieve the goals set out in international agreements. However, it is essential to:

– Invest in research and development of these technologies.

– Ensure sustainability and take into account the social impacts of the implemented measures.

– Integrate negative emissions into broader emission reduction and climate change adaptation strategies.

– Cooperate at the global level to achieve the effective and equitable implementation of these solutions.

Negative emissions are not a substitute for reducing existing emissions, but are a complementary tool in the fight against climate change. The combination of reducing emissions and actively removing CO₂ from the atmosphere is key to ensuring a sustainable future for future generations.