But political action has fallen well behind the pace of scientific progress, and despite growing public support to limit greenhouse gas emissions, the U.S. Senate failed early this month to approve landmark legislation that would have begun to do so.
Dr. Hansen's latest research indicates that greenhouse gas concentrations have already reached damaging levels and the climate is nearing a dangerous tipping point that will unleash far-reaching changes in the atmosphere and oceans that could take millennia to reverse. In his latest paper, Dr. Hansen calls for deep reductions in carbon dioxide emissions, beginning almost immediately, with a focus on phasing out the uncontrolled combustion of coal by 2030.1
As the world moves toward a new climate agreement in 2009, decision makers must understand the tremendous risks we face and the urgency of action in the year ahead.
Although many still argue that such a transition to a low-carbon energy system will be enormously expensive and difficult, our research has shown that it would open up vast economic opportunities, spur innovation and job creation, assist efforts to reduce poverty, and increase energy security.
The transition to a low-carbon economy should be based on sustainable use of renewable sources of energy, including wind, solar, geothermal, and biomass, together with major advances in energy efficiency. The world can achieve a tipping point at which renewables are less expensive than fossil energy-allowing economic momentum to accelerate the transition.
The United States and other industrial nations must work collaboratively with developing countries to increase their capacity to respond to the challenges presented by climate change and to pursue a more viable energy development path. Brazil, China, Europe, India, and the United States together account for 60 percent of global greenhouse gas emissions.
Following Dr. Hansen's recommendations, policymakers should adopt a policy that puts a price on carbon dioxide emissions, halts the construction of uncontrolled coal-fired power plants, and promotes agriculture and forestry practices that will sequester large amounts of carbon.
Achieving the needed energy transformation will require profound changes in government policies, strengthened global governance in the form of a new international climate agreement, and the mobilization of the private sector to develop and deploy a host of new technologies.
'We applaud Jim Hansen for his leadership on this critical issue,' said Worldwatch President Christopher Flavin. 'His warnings show how essential it is that 2008 become a turning point for climate policy as well as climate science-launching the post-fossil fuel economy the world so desperately needs.'