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To limit global warming to 1.5 °C, vast amounts of CO 2 will have to be removed from the atmosphere via Carbon Dioxide Removal (CDR). Enhancing the CO 2 sequestration of ecosystems will require not just one approach but a portfolio of CDR options, including so-called nature-based approaches alongside CDR options that are perceived as more technical. Creating a CDR "supply curve" would however imply that all carbon removals are considered to be perfect substitutes. The various co-benefits of nature-based CDR approaches militate against this. We discuss this aspect of nature-based solutions in connection with the enhancement of blue carbon ecosystems (BCE) such as mangrove or seagrass habitats. Enhancing BCEs can indeed contribute to CO 2 sequestration, but the value of their carbon storage is low compared to the overall contribution of their ecosystem services to wealth. Furthermore, their property rights are often unclear, i.e. not comprehensively defined or not enforced. Hence, payment schemes that only compensate BCE carbon sequestration could create tradeoffs at the expense of other important, often local, ecosystem services and might not result in socially optimal outcomes. Accordingly, one chance for preserving and restoring BCEs lies in the consideration of all services in potential compensation schemes for local communities. Also, local contexts, management structures, and benefit-sharing rules are crucial factors to be taken into account when setting up international payment schemes to support the use of BCEs and other nature- or ecosystem-based CDR. However, regarding these options as the only hope of achieving more CDR will very probably not bring about the desired outcome, either for climate mitigation or for ecosystem preservation. Unhalted degradation, in turn, will make matters worse due to the large amounts of stored carbon that would be released. Hence, countries committed to climate mitigation in line with the Paris targets should not hide behind vague pledges to enhance natural sinks for removing atmospheric CO 2 but commit to scaling up engineered CDR. [ABSTRACT FROM AUTHOR]

Enhancing and conserving carbon pools in vegetation is a major climate change mitigation strategy. The dynamics of carbon in terrestrial ecosystems depend on processes like photosynthesis, respiration, decomposition and combustion, anthropogenic activities like emission of greenhouse gases and climatic variations in rainfall and temperature, and is stored as biomass in different forms. The quantification of biomass is necessary to understand the productivity of forests, carbon sink and source dynamics and recommend ways to aid sequestration through supply side interventions like afforestation and demand side measures that check wood consumption. In this study, carbon sequestration based on the change in total carbon in two different scenarios using Markov chain and InVEST model is evaluated for the years 2000, 2018 and predicted for 2035. The results show that 1.351 Tg carbon has already been lost from 2000 to 2018 in the forest area of Sariska Tiger Reserve and another 0.107 Tg of carbon is expected to be lost in the predicted future, when we compare the land use land cover of the year 2035 with the present scenario. The local communities extract fuelwood by cutting down tree branches illegally, which leads to carbon loss into the atmosphere. The lower release of carbon in 2035 as compared to 2018 is because of forest management practices e.g., plantations done in the range Tehla-Talabberi, Sariska- Ganeshpura, Alwar buffer-Shoydanpura, Talvriksh-Manavaas, Akbarpur-Kalikhol, Ajabgarh-Jatwana. The study shows that the economic value of carbon lost from 2000 to 2018 is million $ 214.57 and if we see the economic value of the predicted year 2035, carbon sequestration is worth million $ 17.19. Outputs demonstrate the potential for restoration/reforestation and afforestation as the most practical carbon loss mitigation strategy and calls for improved access to cleaner energy sources where the renewable energy industry and government may pitch in. Image 1 • Markov chain and InVEST model were used to predict carbon sequestration. • Prediction maps revealed that open forest will be decreased in future. • Total carbon sequestration decreased 1.351 Tg during 2000–18. • It is predicted that −0.107 (Tg) carbon to be sequestered from 2018 to 35. [ABSTRACT FROM AUTHOR]

Urbanisation and the associated growing climate change burdens pose risks to urban and global climate resilience. Urban greenhouse gas emissions fluctuate over time in response to energy demand, which is influenced by government programmes, economic activity, and demographics. In this research, we investigate the influence of policy on urban energy demand and its consequences on mitigating climate change impacts. Using a case study of Lisbon, Portugal from 2008 to 2016, we illustrate a combined use of an urban energy metabolism assessment coupled with a logarithmic mean Divisia index to isolate the changes in energy-related carbon emissions associated with policy changes. We then link these energy flows to life cycle emissions factors to build a multi-level assessment between local and non-local global warming potential. We find that in 2016 Lisbon's energy flows generated more than 2 Mt of CO 2 -equivalent emissions over their life cycles, 48% of which were direct emissions within the city. This corresponds to a decrease of around 37% in greenhouse gas emissions from 2008. Additionally, we estimate the potential of Lisbon's urban forests to sequester these emissions to understand the potential for climate change mitigation. Results show that Lisbon's urban forest can meet less than 1% of the emissions throughout the assessment period. We discuss the changes, concluding that urban forests are insufficient in size to meet the sequestration demands of the urban energy metabolism, and therefore the focus must be more attuned to reducing fossil fuel use in the urban trade and transport activities. • Carbon emissions from Lisbon's urban energy metabolism are dominated by diesel use in the trade and transportation sectors. • Carbon emissions from Lisbon's urban energy metabolism have decreased following energy policy interventions. • Less than 1% of Lisbon's energy-related carbon emissions are sequestered by urban forests. • Urban forests are insufficient in size to mitigate the demand for carbon sequestration. • Energy policy must focus on reducing urban demand for diesel and petrol by transport activities. [ABSTRACT FROM AUTHOR]

We use a dynamic global forest model to examine how U.S. tax reform could influence forest stocks and carbon sequestration. Scenario analysis estimates several impacts from adjusting current policies that affect timberland investment, area, harvests, and carbon. First, increases in tax rates faced by timberland owners cause timber assets to be revalued downward even though the physical forest is initially unchanged, resulting in substantial declines in both regeneration and management. Second, timber stocks fall over time, reflecting a decrease in investment. Third, tax revenues could increase by nearly $3.4 billion/yr compared to baseline, but at the expense of increasing trade deficits by up to $3.3 billion/yr. Fourth, timberland area could decrease by 12 million hectares. Last, cumulative carbon sequestration over the next 50 years could be reduced by more than 3 billion tCO2e, −22% from the current policy baseline if forestland tax incentives are removed. Fifth, maintaining the existing tax policies in perpetuity incentivizes carbon sequestration levels equivalent to imposing a price of $70/tCO2e on the forest sector, highlighting the ecosystem service benefits of maintaining current tax policy. Finally, we estimate that current US forest tax policy provides about $8 billion/yr in climate change mitigation benefits by 2050. • We model the impact of current forest taxation policy on the U.S. timber sector. • Tax provisions incentivize management, conservation, and carbon sequestration. • U.S. forest carbon could be reduced by 22% if tax provisions are removed. • Current policy equates to a carbon price of $70/tCO 2 e without tax incentives. [ABSTRACT FROM AUTHOR]