National greenhouse gas (GHG) mitigation strategy can benefit from information on the technical and economic viability of abatement options. The life-cycle-analysis (LCA) and marginal abatement cost curve (MACC) approaches provide a good, although partial, indication for the potential of existing technologies to mitigate GHG emissions. The input-output (IO) approach has advantages in capturing the indirect impacts of technology adoption from shifts in economic structure and linkages between sectors. It is therefore ideal to develop an integrated approach to more accurately assess the overall economic and environmental impacts of climate policy. In this study, we aim to develop such an approach that extends the assessment of viability to include indirect economic and environmental effects of resulting structural shifts in the economy. The new approach is applied to technological GHG mitigation measures in Northern Ireland’s cattle sectors. The main findings indicate there is a marked difference (even reversal under some conditions) in the overall impact of technical reductions in emission-intensity on national output and emissions when adjustments in economic structure are taken into account.