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