Governments of the world are now launching climate change negotiations for after 2012, when the Kyoto Protocol expires. World leaders acknowledge that civilization is on a dangerous course. Yet there is still little consensus about how to achieve stabilization of greenhouse gases.

We suffer no shortage of ideas about the instruments of action. For example, the world’s governments could impose taxes on carbon emissions that are high enough to choke off the use of fossil fuels in favor of higher-cost but cleaner alternatives. Or they could impose a system of tradable permits that would have the same effect. The problem is not mainly with the instruments but with their unknown costs and benefits. We know we need to act immediately, but because of big uncertainties regarding key technologies, we cannot precisely calibrate the costs and benefits of alternative actions.

The biggest obstacle is that the most promising scalable technologies, such as carbon capture and sequestration (CCS) and plug-in hybrid vehicles, are close to introduction but not quite there yet. China and India probably will not bet their future on CCS until the technology is proved, yet neither country has even one demonstration plant. Similarly, it is a little early to count on plug-in hybrids delivering 100 miles per gallon, a goal well within reach, until the first one rolls off the assembly line, with batteries that are safe, efficient, long-lasting and reliable.

How then can the world agree on meaningful targets and avoid a 10-year squabble or empty gestures? Rather than aiming for a single grand outcome from the new round of negotiations, we should proceed in meaningful steps, taking ground where we can at known low cost and aggressively proving the new technologies that we will need. For example, it would be possible now to seal an international agreement in which the rich countries will pay the poorest countries not to cut down their forests, because the evidence is very clear that most deforestation can be avoided at low cost (perhaps $10 per ton of avoided carbon dioxide) and with enormous global ecological benefits.

It would also be possible for the major coal-producing regions to agree to adopt several demonstration projects of CCS technology in the power sector. On average, each of these CCS power plants will require around $300 million to $500 million over 10 years beyond the cost of a conventional plant. China and India are prepared to introduce these unproved, more expensive yet cleaner technologies if the U.S., Japan and Europe help to pay for them. An agreement on financing at least two large-scale CCS projects in India and China could be achieved within the next few months.

A third area of agreement would be a worldwide public-private partnership on plug-in hybrids. A major global effort on battery design could provide the key technological breakthrough needed. A coordinated policy effort could help each region to prepare its power grid for a massive introduction of this new technology within the next five to 10 years. A fourth area would be shared, binding commitments to scale up the adoption of existing low-emissions technologies, such as hybrids, diesel automobiles and energy-efficient lighting. These can be achieved by agreeing to impose standards on industries (for example, setting maximum emissions per passenger mile on new automobile sales) while leaving the precise choice of technologies for meeting those standards to the marketplace.

It is also within our grasp today to agree on overarching principles: that the world will aim to stabilize greenhouse gas emissions at safe levels no later than 2050; that countries will work together to develop and disseminate scalable low-emissions technologies; that the rich nations will pay for the bulk of research, development and demonstration and make the technologies available for global use equitably; and that the world will agree on progressively tighter and binding targets and market prices on emissions, as scalable low-cost, low-emissions technologies are developed and demonstrated.

Such a step-by-step approach will not produce a grand bargain in a single swoop. Instead it could demonstrate concrete and meaningful actions from the very start—and without years of wrangling. Within five years, there would be an excellent chance that proved, scalable and inexpensive technologies could support even bolder targets for greenhouse gas stabilization.