Climate talks in Doha last week highlighted the weakness of carbon targets as a tool to limit climate change while a lack of international financial and political support may equally undermine an alternative, technology-led approach.
The talks achieved no new targets to cap emissions, which was no surprise given the complexity of agreeing responsibility for climate action between countries and chiefly between China and the United States.
A negotiator from Belarus on Monday threatened to pull out of a second, limited round of the Kyoto Protocol agreed just 48 hours earlier after belatedly realising the constraint on the country's emissions, underlining the problem with a carbon caps approach that is onerous and divisive.
Pending an agreement on global emissions targets, which may never happen, one potentially less contentious alternative is to agree mandatory global benchmarks for residential, automotive and industrial efficiency, among other technology policies and measures.
Global minimum standards could apply, for example, to the adoption of standby power policies; the phase out of inefficient lighting; minimum energy performance requirements for appliances and equipment; vehicle tyre rolling resistance; and the carbon emissions of passenger cars.
The range of vehicle fuel economy standards worldwide illustrates the scope for progress, where the European Union leads, followed by Japan, the United States, the Republic of Korea, Canada, Australia and then emerging economies.
A voluntary approach is supported by multiple initiatives including a "clean energy ministerial" collaboration between major economies, and by the International Organisation for Standardisation (ISO), the world's largest developer and publisher of international standards.
Barriers to a more formal or mandatory approach include a lack of financial backing for such multilateral efforts.
The benefits of energy efficiency are obvious: it boosts energy security and the environment; can be achieved at negative cost and offers big industrial energy savings in developing countries and in residential consumption in advanced economies.
Global adoption by 2030 of IEA efficiency recommendations would cut annual global carbon emissions by nearly a quarter of today's levels, the energy adviser estimates.
That is far greater than the impact of Kyoto's first round of targets which only limited industrialised countries, aiming to cut their carbon by 5.2 percent compared with 1990 levels.
Efficiency upgrades can be done at negative cost because the lifetime energy savings outweigh the upfront cost.
In advanced economies, home appliances and electronics are the fastest growing source of residential energy consumption, as illustrated by U.S. Energy Information Administration data, rising faster than space and water heating and cooling.
In former communist and emerging economies industrial efficiency offers the main opportunity.
According to the IEA, if Russia had used energy as efficiently as Canada (with its equivalent climate) in 2008 it would have cut the country's energy consumption by one third that year.
There have been few trade disputes regarding the unilateral adoption of efficiency and fuel economy standards, because the World Trade Organisation's (WTO) 1995 Agreement on Technical Barriers to Trade (TBT) explicitly allows these.
"No country should be prevented from taking measures necessary to ensure the quality of its exports, or for the protection of human, animal or plant life or health, of the environment, or for the prevention of deceptive practices, at the levels it considers appropriate," it says.
Agreeing global benchmarks is another matter, however.
In general, large multinational companies are in favour of globally harmonised standards to simplify production and cut red tape, but such standards may hurt smaller producers with more limited resources.
An IEA paper in 2005 sought to quantify the consumer cost of improving the energy efficiency of air conditioning, in China versus Japan, finding a clear rise in purchase price with improved efficiency.
That acted as a disincentive coupled with weak national s tandards and poor R&D resources among smaller Chinese manufacturers, the report found.
The main barrier against multilateral efforts on efficiency centres on financial backing.
The United States launched the "clean energy ministerial" process in 2009, arising from the U.N. climate talks, involving regular meetings of some 23 countries. The talks included the United States, Canada, major EU countries, Japan, China, India and Brazil in a good example of cooperation, which contrasts with the rich-poor standoff in climate negotiations.
The initiative's web page says it is presently seeking international technical cooperation on standards and labelling in refrigeration, computing, distribution transformers, televisions, standby modes and efficient lighting.
But that five-year "Super-Efficient Equipment and Appliance Deployment" initiative has just $20 million backing.
That contrasts with massive domestic backing, such as $4.5 billion for U.S. state-level electricity efficiency programmes in 2010, and is feeble support for a centrepiece in multilateral cooperation.
As the World Energy Council said in a review of efficiency measures in 2008: "Although some convergence can be observed in the policy measures across countries, there are still many differences. In general, co-ordination at international level could be reinforced to help overcome obstacles to the implementation of both standards and price signals."
Gerard Wynn is a Reuters columnist.