Reducing sectoral hard to abate emissions to limit reliance of Carbon Dioxide Removal in 1.5°C scenarios

Achieving net-zero greenhouse gas targets is often achieved by compensating residual greenhouse gas emissions in the hard to abate (HtA) sectors, with carbon dioxide removal (CDR) options. However, large-scale application of CDR may lead to environmental, technical and social concerns. The extent to which residual emissions can be reduced in the industry, agriculture, buildings and transport sector is analysed based on integrated assessment of scenarios with ambitious measures in the HtA sectors. Two scenarios that explore demand and technology-focused approaches show that by reducing residual emissions, the CDR ceiling can be significantly lowered (23-30%) compared to reference in the net-zero year. The agriculture sector plays a critical role in this given the large share of residual emissions. The additional measures allow to create a 1.5°C scenario in which crop-based bioenergy use is limited to 40 EJ/yr, therefore within sustainable limits, and afforestation can be limited to abandoned cropland and grassland

Efficiency improvement and technology choice for energy and emission reductions of the residential sector

The residential sector currently accounts for one fifth of global energy use and corresponding greenhouse gas emissions, largely driven by increasing demand for space heating and cooling. Climate change mitigation action requires these to reduce, but the exact decarbonization strategies, the contribution of demand and supply side measures, and their heterogeneity is unclear. Using a regional energy system model with an explicit representation of residential energy use and building stocks, the contribution of this sector in long-term decarbonization pathways is explored. The projections show that in a 2°C scenario, global heating demand is expected to decrease from current levels by 27% and 66% by 2050 and 2100, respectively. However, due to increasing affluence in warmer regions, cooling demand is expected to increase by 176% and 286% respectively. Yet, direct residential emissions are almost eliminated by 2100 by combining increased envelope efficiency and advanced heating technologies in a synergistic manner, where the adoption of high efficiency heating and cooling reduces the need for increased insulation, and vice versa. By combining these measures with rooftop PV, the net energy demand of many household types approaches zero. The exact residential sector strategies vary across local climate, socio-economic, and building stock characteristics

Efficiency improvement and technology choice for energy and emission reductions of the residential sector

The residential sector currently accounts for one fifth of global energy use and corresponding greenhouse gas emissions, largely driven by increasing demand for space heating and cooling. Climate change mitigation action requires these to reduce, but the exact decarbonization strategies, the contribution of demand and supply side measures, and their heterogeneity is unclear. Using a regional energy system model with an explicit representation of residential energy use and building stocks, the contribution of this sector in long-term decarbonization pathways is explored. The projections show that in a 2°C scenario, global heating demand is expected to decrease from current levels by 27% and 66% by 2050 and 2100, respectively. However, due to increasing affluence in warmer regions, cooling demand is expected to increase by 176% and 286% respectively. Yet, direct residential emissions are almost eliminated by 2100 by combining increased envelope efficiency and advanced heating technologies in a synergistic manner, where the adoption of high efficiency heating and cooling reduces the need for increased insulation, and vice versa. By combining these measures with rooftop PV, the net energy demand of many household types approaches zero. The exact residential sector strategies vary across local climate, socio-economic, and building stock characteristics