This week and next, diplomats from around the world gather once again to discuss global warming. With commitments under the Kyoto Protocol ending this year (see page 653), one key goal of the United Nations meeting in Doha is to make progress towards the 2015 signing of a new global climate treaty, to take effect by 2020. The world is on track for a temperature increase of up to 4 °C by the end of the century, but the UN hopes to limit that to just 2 °C.

Unfortunately, diplomacy and global warming operate on incompatible schedules. An eight-year wait for action would seem to put the warming goal firmly out of reach. But there are ways to buy time for global diplomacy, and energy efficiency is at the top of the list.

The World Energy Outlook 2012 report from the International Energy Agency (IEA) suggests that the global infrastructure could lock in enough carbon emissions by 2017 to exceed the 2 °C goal, unless facilities such as power plants, factories and buildings are expensively retrofitted or prematurely retired. But the IEA found that improving energy efficiency could give the world another five years to change course and begin the transition to renewables and other low-carbon energies.

Globally, energy use is projected to increase by more than one-third by 2035, despite promises by Japan, Europe, China and the United States to curb demand. In an ‘efficient world’ scenario, with more countries embracing bigger efficiency goals, the projected energy demand could be cut by half. For perspective, the IEA estimates that the modest efficiency increases achieved between 1980 and 2010 reduced global energy demand by 35% — roughly equivalent to the energy currently consumed by China and the United States combined.

The IEA suggests that more-aggressive efficiency measures, such as a broad shift toward efficient appliances, vehicles, homes and factories, would cost an extra US$11.8 trillion between now and 2035. But the pay-off would be substantial: direct fuel expenditures would fall by $17.5 trillion, and investments in energy infrastructure by nearly $5.9 trillion. Those savings would be reinvested elsewhere, helping to increase global economic output by some $18 trillion. Unfortunately, the potential gains are dispersed throughout a complex marketplace that tends to reward short-term thinking.

Improving energy efficiency could give the world another five years to change course.

Governments must pursue solutions at all levels, and not wait until the next global treaty. Reducing subsidies on fossil fuels would cut energy consumption, for instance, as would increasing consumption taxes. High energy taxes help to explain why Japan and Europe are leaders in energy efficiency, just as increasing oil prices on the global market have encouraged Americans to reduce their oil consumption.

But playing with the price won’t work if the signals aren’t reaching the right people. Buildings are responsible for roughly one-third of global greenhouse-gas emissions, but builders have no incentive to invest in energy-efficient technologies if tenants and owners will foot the energy bill. To change that, governments can strengthen building codes for new construction and create financial incentives that reduce the up-front costs of retrofitting. They can also require energy audits when properties are sold; this encourages buyers and sellers alike to consider long-term operating costs.

In Doha and beyond, negotiators must look for opportunities for the world to embrace new and more ambitious climate goals. At the same time, governments must do everything they can to follow through with their own climate commitments, reduce carbon footprints at home and lay the groundwork for future steps. Stabilizing the climate will require monumental efforts on all fronts, and governments should recognize that money spent now on curbing greenhouse-gas emissions is a long-term investment that will pay off down the road. Nowhere is this clearer than in the arena of energy efficiency.