According to a research report from Paris-based The Global Buildings Performance Network, the building sector has the power to paint three very different energy pictures--all of which will be determined by how ambitious our policy decisions are today.

Using scenario analysis, researcher Diana-Urge Vorsatz and a team at the Central European University reviewed 18 global and selected regional studies to assess the importance of the buildings sector in mitigating climate change and to offer policy insights on how the savings potentials can be best captured.

Among its many findings, the researchers say that first and foremost, the research confirms the widespread hypothesis that buildings represent a huge opportunity to decrease energy consumption and emissions. Based on their assessment, by 2050, it is possible to reduce absolute final thermal energy use in the building sector by almost one-third and almost halve the related CO2 emissions--even with a 127% increase in floor area. Considering that buildings account for about a third of total global final energy demand and about 30% of global energy-related CO2 emissions, that’s a fairly significant savings.

That is the encouraging news. However, on the other hand, if we were to take no policy action and continue approaching construction and retrofits like we do today, we could see energy use increase by 111% compared to 2005 levels, representing what the authors are calling the “frozen efficiency scenario.”

Perhaps the most sobering finding was that of the “moderate efficiency scenario.” Based on the analysis, even if today’s most ambitious policies were fully implemented, global building energy use could still increase by almost half (about 48%) compared to 2005. As stated in the report, this highlights “the significant gap between what is possible and where even today’s ambitious policy trends are taking us.” In other words, even today’s best efforts are not enough to make any real progress.

So what needs to be done? In order to achieve the positive energy scenario—what the authors are calling the “deep efficiency scenario”—the authors say we will have to push the efficiency lever as far as possible. “This potential can be realized by wide implementation of energy efficiency state-of-the-art solutions, which already exist on the market, including integrated sustainable design for new buildings and holistic ‘deep’ renovation of existing ones,” notes Ksenia Petrichenko, a member of the research team. This, he says, will require “strong political support.”

Specifically, the researchers found that policies will need to focus on holistic (systemic) efficiency opportunities, as opposed to the efficiency of individual building components, and that optimized mitigation over a longer period achieved higher reductions than those focused on the short term. “This points to the critical importance of strategic, long-term policy making and the stability of policy structure,” the authors state.

Another key finding was that urban-level policies will be critical. The analysis found that 85% of growth in building energy use during the projection period comes from urban areas, 70% of which is coming from developing country cities. Based on this finding, the authors contend that policies and programs that are defined and implemented by cities can play an equally important (perhaps even larger) role in curbing building thermal energy use as those by national governments.

On a regional scale, the report states that policies in the U.S. and Europe need to focus most of their efforts on retrofits, whereas policies in India and China should focus more on new construction and limiting residential per capita floor space.

The authors stress that policymakers need to act now, as any delay will result in a high cost. For example, if policy efforts are not ambitious enough (i.e., “moderate efficiency scenario”), global thermal energy use will increase 46% by 2050 and, in turn, will actually “lock in” 80% of the thermal final energy use due to the long-term presence and relatively slow major retrofit cycle of the built infrastructure. So even if ambitious climate mitigation targets become the policy targets later, the authors say it will not be possible to access much of this unlocked potential, unless only at prohibitive costs.

The analysis also concluded that energy efficiency improvements aren’t going to be enough to achieve this “deep efficiency” scenario. “Even a very ambitious proliferation of energy-efficient best practices is insufficient to achieve vital global greenhouse gas reduction targets,” Petrichenko says. “Therefore, reducing building energy demand has to be accompanied by the de-carbonization of energy supply through wide utilization of renewable energy in buildings and significant behavioral and lifestyle changes.”

Click here to read the entire report, “Best Practice Policies for Low Carbon & Energy Buildings.”