Decarbonization: Doing more with less

This article demonstrates that large decreases in energy requirements per unit economic output were achieved throughout the world and that carbon emissions have also decreased per unit energy. Energy is one of the most important factor inputs so that decreases in specific energy requirements contribute toward decreasing material intensity. Carbon dioxide emissions represent one of the largest single mass flows associated with human activities. Therefore, decarbonization contributes in a large way toward dematerializaton. At the global level decarbonization occurs at about 0.3% per year, and reduction of energy intensity of value added stands at 1% per year, resulting in overall carbon intensity of value added reduction of about 1.3% per year. The pervasiveness of decarbonization in the world, is illustrated for five representative countries. The case histories show that developing countries are undergoing basically the same process of decarbonization of final energy use as do most developed ones. However, carbon intensity of primary energy is increasing in some developing countries and should a reversal not occur in the forthcoming decades, it is likely the decarbonization in the industrialized countries could be offset by this tendency. Thus, the possibility cannot be entirely excluded that carbon dioxide emissions would increase faster than economic growth. These opposing tendencies could be bridged in the future if the energy system restructures toward larger reliance on natural gas, biomass, nuclear energy, and other zero-carbon options. For example, the methane economy could lead to a greater role for energy gases (and later hydrogen) in conjunction with electricity. Such an energy system would represent a gigantic step toward decarbonization and it would also be consistent with the emergence of new technologies that hold the promise of higher flexibility, productivity, and environmental compatibility.