Nathan Rive

Costs and global impacts of black carbon abatement strategies

Abatement of particulate matter has traditionally been driven by health concerns rather than its role in global warming. Here we assess future abatement strategies in terms of how much they reduce the climate impact of black carbon (BC) and organic carbon (OC) from contained combustion. We develop global scenarios which take into account regional differences in climate impact, costs of abatement and ability to pay, as well as both the direct and indirect (snow-albedo) climate impact of BC and OC. To represent the climate impact, we estimate consistent region-specific values of direct and indirect global warming potential (GWP) and global temperature potential (GTP). The indirect GWP has been estimated using a physical approach and includes the effect of change in albedo from BC deposited on snow. The indirect GWP is highest in the Middle East followed by Russia, Europe and North America, while the total GWP is highest in the Middle East, Africa and South Asia. We conclude that prioritizing emission reductions in Asia represents the most cost-efficient global abatement strategy for BC because Asia is (1) responsible for a large share of total emissions, (2) has lower abatement costs compared to Europe and North America and (3) has large health cobenefits from reduced PM10 emissions.

Carbon capture and storage deployment rates: needs and feasibility

Carbon capture and storage (CCS) may become a key technology to limit human-induced global warming, but many uncertainties prevail, including the necessary technological development, costs, legal ramifications, and siting. As such, an important question is the scale of carbon dioxide abatement we require from CCS to meet future climate targets, and whether they appear reasonable. For a number of energy technology and efficiency improvement scenarios, we use a simple climate model to assess the necessary contribution from CCS to ‘fill the gap’ between scenarios’ carbon dioxide emissions levels and the levels needed to meet alternative climate targets. The need for CCS depends on early or delayed action to curb emissions and the characteristics of the assumed energy scenario. To meet a 2.5°C target a large contribution and fast deployment rates for CCS are required. The required deployment rates are much faster than those seen in the deployment of renewable energy technologies as well as nuclear power the last decades, and may not be feasible. This indicates that more contributions are needed from other low-carbon energy technologies and improved energy efficiency, or substitution of coal for gas in the first half of the century. In addition the limited availability of coal and gas by end of the century and resulting limited scope for CCS implies that meeting the 2.5°C target would require significant contributions from one or more of the following options: CCS linked to oil use, biomass energy based CCS (BECCS), and CCS linked to industrial processes.