Recently UNEP released a report underlying the emission gap and policing in countries. Here we are discussing the role of negative emission technologies in emission controlling, as seen from the report uploaded in the Safety4Sea website.
CDR technology
Carbon dioxide removal (CDR) refers to various approaches to reducing atmospheric concentrations of carbon dioxide by removing it from the air. In addition to land-use changes such as afforestation, reforestation, and ecological restoration, technological
methods currently under investigation include using bioenergy with carbon capture and storage (BECCS) and direct air capture (DAC).
How CDR can help?
Using CDR can make it possible to exceed the carbon budget in the near-term and make up for it by later removing CO2 from the atmosphere. It can allow for a slower and more orderly winding down of fossil fuel production, while taking pressure off sectors, such as aviation, where mitigation is particularly costly or otherwise challenging (Creutzig et al. 2015).
Reflecting these potential benefits, Integrated Assessment Models (IAMs) have introduced CDR technologies as mitigation options, along with assumptions about future cost competitiveness. Practically all IAMs rely heavily upon carbon dioxide removal to
achieve net negative CO2 emissions in the second half of the century (van Vuuren et al. 2017).
Nonetheless, the IPCC Special Report on Global Warming of 1.5°C underscores that “CDR deployed at scale is unproven, and reliance on such technology is a major risk in the ability to limit warming to 1.5°C” owing to “multiple feasibility and sustainability concerns” (Rogelj et al. 2018, p. 96).
Risks include:
- Negative emission options may not ultimately prove technically or biophysically achievable or affordable. Scenarios rely most heavily on BECCS for power plants, which has not yet been demonstrated (Fuss et al. 2018; van Vuuren et al. 2013).
- The large-scale deployment of CDR may involve unacceptable ecological and social impacts. CDR could, for example, compete with food production or habitat areas for available land, with the potential for adverse impacts on biodiversity, food security, water resources, and human rights (Dooley et al. 2018).
- BECCS is inherently land-intensive: IAM scenarios assembled for the IPCC Fifth Assessment Report assumed that between 245 million hectares and about 1.5 billion hectares of agricultural land would be dedicated to bioenergy crops, compared to the approximately 1.5 billion hectares currently devoted to agriculture (Popp et al. 2017)
- Negative emissions activities could prove less effective than hoped. Land-based carbon stocks are vulnerable to release through human action or natural forces.
And as noted in the Special Report, “carbon cycle and climate system understanding is
still limited about the effectiveness of net negative emissions to reduce temperatures after they peak” (IPCC 2018, p. 19).
CDR Limiting Climate Change
If CDR proves feasible and sustainable at large scale, then it could prove an important tool for limiting climate change. Scenarios that use CDR have been included here, but none that exceed the upper end of the range of estimates by Fuss et al. (2018) (as cited in the IPCC 1.5°C Special Report) for sustainable global potentials for BECCS (5 GtCO2/year) and afforestation and reforestation (3.6 GtCO2/year). That said, it is a relatively modest constraint, as even such limits are subject to “a heavy caveat of uncertainty” and hence do pose significant risks (Fuss et al. 2018).
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Source: Safety4Sea
