The scenarios illustrate that pervasive changes in economic development, energy end-use patterns, and energy supply systems take considerable time. It may take some three decades before FSU's economic restructuring is over and at least five decades before the region catches up to Western Europe's 1990 per capita GDP level. Catching up to WEU standards takes AFR and SAS even longer, extending all the way through the 21st century. And even with the ambitious efforts of Case C, it will take almost a century to restructure the global energy system away from its current dominant reliance on fossil fuels.
This was too slow for some reviewers. The CPA and SAS regional reviews, for example, argued for higher rates of both economic growth and energy intensity improvements than those considered feasible in the scenarios. Faster economic growth concurrent with faster energy intensity improvements is consistent with historical experience and the logic underlying the scenarios. The two together do not dramatically alter the evolution of energy demand as described in the scenarios, although faster economic development would mean a developing region could catch up to developed countries more quickly. As emphasized in many regional reviews, however, high growth requires a skilled population, a stable political climate, functioning institutions and markets, free trade, and access to advanced technology.
The CPA regional review also raised the possibility of switching between alternative development paths. For CPA, a preferred alternative scenario would start on a coal-intensive trajectory (Scenario A2) but, after 2020, switch to less carbon-intensive fuels (Scenario A3). Such a transition might be partially possible if carefully planned.
However, from the perspective of the global analysis, changing horses in midstream creates two principal difficulties. First, infrastructural and technological investments in coal ultimately will have to be duplicated by new investments in energy alternatives. The railway infrastructure for coal transport, the coal-fired power plants, and the work force dedicated to coal will be in place and expanding, making it ever more difficult to change course. Second, the required massive technological shift would cost more after 2020 than if less carbon-intensive fuels had been the focus of investments right from the beginning. There will not have been the same learning, experience, and cost reductions for the new technologies as would have occurred had they been the original focus of investments.