A new research has suggested that reducing global emissions of carbon dioxide (CO2) over the coming century will be more challenging than society has been led to believe.
The research was carried out by scientists from the University of Colorado at Boulder, the National Center for Atmospheric Research (NCAR) in Boulder, and McGill University in Montreal.
According to them, the technological challenges of reducing CO2 emissions have been significantly underestimated by the Intergovernmental Panel on Climate Change (IPCC).
The study said that the IPCC is overly optimistic in assuming that, even without action by policymakers, new technologies that will result in dramatic reductions in the growth of future emissions will be developed and implemented.
"The IPCC plays a risky game in assuming that business-as-usual advances in technological innovation will carry most of the burden of achieving future emissions reductions, rather than focusing on those conditions that are necessary and sufficient for those innovations to occur," said Cliff Jacobs of the National Science Foundation (NSF)'s Division of Atmospheric Sciences.
Atmospheric CO2 levels are currently about 390 parts per million. A commonly cited goal is to stabilize concentrations at roughly 500 parts per million or less.
Because technical innovation is ongoing, the IPCC authors assume that most of the needed reductions will occur automatically.
According to calculations, the IPCC assumes that 57 to 96 percent of the total carbon removed from the energy supply will occur automatically through such routine technological progress.
The reason for the IPCC's underestimate of carbon intensity changes lies partly in the way the IPCC emissions scenarios partition future emissions changes into those that will occur spontaneously and those that are policy-driven, according to the scientists.
This partitioning underestimates the full magnitude of the technology challenge associated with stabilizing the amount of carbon dioxide in the atmosphere.
"According to the IPCC report, the majority of the emission reductions required to stabilize CO2 concentrations are assumed to occur automatically," said scientist Roger Pielke.
"Not only is this reduction unlikely to happen under current policies, but we are moving in the opposite direction right now. We believe these kinds of assumptions in the analysis blind us to reality and could potentially distort our ability to develop effective policies," he added.
According to Tom Wigley of NCAR, "Stabilization is a more daunting challenge than many realize and requires a radical 'decarbonization' of energy systems."
"Global energy demand is projected to grow rapidly, and these huge new demands must be met by largely carbon-neutral energy sources - sources that either do not use fossil fuels or that capture and store any emitted CO2," he added.