The need to reduce carbon emissions globally has never been more important as the climate emergency intensifies. Despite advancements in renewable energy adoption and industrial decarbonisation, persistent emissions from hard-to-abate sectors, accumulated greenhouse gases, and ongoing emission trends continue to present major obstacles. In this context, Negative Emissions Technologies (NETs) have emerged as a promising solution to remove carbon dioxide (CO₂) from the atmosphere. By complementing traditional emissions reduction strategies, NETs offer a pathway to bridge the emissions gap, meet global climate targets, and support corporate sustainability efforts to restore balance to the planet’s carbon cycle.
What are Negative Emissions Technologies (NETs)?
Negative Emissions Technologies (NETs) are innovative solutions designed to actively remove carbon dioxide from the atmosphere and store it permanently, helping to offset greenhouse gas emissions.
Negative Emissions Technologies examples:
- Direct Air Capture (DAC): Captures CO₂ directly from ambient air using chemical processes. The captured carbon can then be stored underground or used in industrial applications.
- Bioenergy with Carbon Capture and Storage (BECCS): Combines biomass energy production with carbon capture, storing emissions underground to create a net-negative carbon cycle.
- Afforestation and reforestation: Planting new forests (afforestation) or restoring degraded forests (reforestation) to absorb CO₂ through natural photosynthesis.
- Soil carbon sequestration: Enhances soil’s capacity to store carbon by adopting regenerative agricultural practices, such as reduced tillage and cover cropping.
- Biochar: Producing biochar (charcoal) by heating organic matter in low-oxygen environments and adding it to the soil to lock carbon for centuries.
- Enhanced weathering: Speeds up the natural process of minerals absorbing CO₂ by spreading finely ground minerals like basalt over large land areas.
- Ocean-based NETs: Techniques like ocean fertilisation, where nutrients are added to stimulate phytoplankton growth, and alkalinity enhancement to increase the ocean’s CO₂ uptake capacity.
The potential of NETs
Negative Emissions Technologies (NETs) hold significant potential for mitigating climate change by actively removing CO₂ from the atmosphere. These technologies complement emissions reduction efforts. They offer a pathway to address residual emissions from hard-to-abate sectors, counterbalance historical emissions, and help achieve net zero.
NETs are crucial for bridging the emissions gap between current trajectories and the Paris Agreement goals of limiting global warming to 1.5°C or 2°C. According to the IPCC, achieving these targets will require removing 5-10 gigatonnes of CO₂ annually by mid-century.
Additionally, NETs are essential for offsetting emissions from sectors like aviation, shipping, and heavy industries, which face significant challenges in fully decarbonising. By removing unavoidable emissions, NETs enable these industries to align with global net-zero targets. Another critical area where NETs contribute is reversing historical emissions.
As greenhouse gas concentrations have already destabilised the climate, NETs provide a solution to actively reduce atmospheric CO₂, slowing or reversing the effects of climate change. By enhancing natural carbon sinks through afforestation, reforestation, soil carbon sequestration, and ocean-based solutions, NETs also deliver significant co-benefits such as biodiversity restoration, improved soil fertility, and enhanced water retention.
Challenges and limitations
Negative Emissions Technologies (NETs) offer promising solutions for removing CO₂ from the atmosphere, but they face significant challenges and limitations that must be addressed to unlock their full potential. Below are some of the key issues:
High costs and energy demand
Many NETs, such as Direct Air Capture (DAC) and Bioenergy with Carbon Capture and Storage (BECCS), are costly to deploy at scale. DAC, for example, requires significant energy input to capture and store CO₂ from the atmosphere due to its low concentration. The economic feasibility of these technologies remains a major barrier, as substantial financial investments are needed to improve efficiency and reduce costs.
Competition for resources
Several NETs compete for scarce natural resources such as land, water, and biomass. Large-scale BECCS, afforestation, and reforestation can displace agricultural production, threaten food security, and impact local water availability. This competition raises concerns about sustainability and equitable resource allocation, particularly in regions already facing resource constraints.
Environmental risks
Some NETs carry unintended consequences for ecosystems. For instance, ocean fertilisation, which stimulates algae growth to sequester CO₂, can disrupt marine ecosystems. This can cause oxygen depletion, and alter food chains. Similarly, large-scale afforestation with non-native species could threaten biodiversity and degrade existing ecosystems. These risks highlight the need for careful planning and deployment to avoid exacerbating environmental problems.
Technological uncertainty and scalability
Many NETs remain in the early stages of development, with limited demonstration projects and insufficient data on long-term performance. Technologies like Enhanced Weathering and DAC are still undergoing testing, and questions remain about their ability to operate effectively and economically at the scale required to achieve meaningful climate impact.
Delayed climate action risk
NETs are sometimes seen as a fallback solution, which may lead to delayed emissions reductions. Relying too heavily on future NETs risks allowing continued greenhouse gas emissions today, potentially overshooting critical climate thresholds and locking in irreversible damage.
Storage and permanence issues
The long-term storage of sequestered carbon remains a concern. For example, CO₂ stored underground through BECCS or DAC must remain securely trapped for thousands of years. There is also the risk of leakage or re-release of carbon due to geological disturbances or improper management.
Conclusion
Negative Emissions Technologies (NETs) represent a groundbreaking step in combating climate change, offering the potential to reduce atmospheric CO₂ while complementing existing mitigation strategies. However, it is vital to recognise that NETs are not a substitute for immediate and decisive carbon reduction efforts.
Achieving global climate goals will require a dual approach: tackling emissions at their source and leveraging innovative technologies like NETs to restore balance to our planet’s ecosystems. Equip yourself with the right tools and knowledge to drive meaningful change with our Certificate in Decarbonisation: Achieving Net Zero. Our comprehensive sustainability education empowers individuals and businesses to lead the way toward a low-carbon future.
