New system could provide detailed images — even of soft tissue — from a lightweight, portable device.
Regulations alone will not stabilize climate or curb global warming, says an international team of climate and technology experts that includes an MIT engineer. What's needed is the development of advanced technologies for alternative sources of energy that allow both climate stabilization and economic development.
In a paper published in the Nov. 1 issue of Science, the researchers evaluate several advanced energy technologies for their ability to supply carbon-emission-free energy and their potential for large-scale commercialization. They found that no existing alternative energy source or combination of sources could adequately replace the energy produced by fossil fuels.
The team's conclusion: massive research commitments are needed to develop these technologies to effectively slow global warming.
"To reduce greenhouse gas emissions from our energy systems while maintaining energy prices at comparable levels to today will take revolutionary change as opposed to evolutionary change," said Howard J. Herzog, a principal research engineer at MIT's Laboratory for Energy and the Environment and co-author of the Science paper.
The study's call for prompt and aggressive energy research and development distinguishes it from the Bush administration's energy plan, which focuses on domestic oil exploration, and the recent United Nations Intergovernmental Panel on Climate Change "Mitigation" report, which indicates that existing technologies can stabilize human-induced adverse climate change.
During the last century, the concentration of atmospheric carbon dioxide has increased from about 275 parts per million to about 370 parts per million. Unchecked, it will pass 550 parts per million by the end of this century, the report says. Climate models and paleoclimate data indicate that 550 parts per million of carbon dioxide, if sustained, could eventually produce global warming comparable in magnitude (but opposite in direction) to the global cooling of the last Ice Age.
"What our research clearly shows is that scientific innovation can only reverse this trend if we adopt an aggressive global strategy for developing alternative fuel sources that can produce up to three times the amount of power we use today," said Martin Hoffert, a professor of physics at New York University and the leader of the research team. "Currently, these technologies simply don't exist, either operationally or as pilot projects."
The team focused on alternative energy sources including terrestrial solar, wind, biomass, nuclear fission, nuclear fusion and fission-fusion hybrids. The team also explored non-primary power technologies that could contribute to climate stability and slowing down global warming, such as conservation, hydrogen production, superconducting global electric grids and geoengineering.
Another possible approach that could help buy time is sequestration - where carbon dioxide emitted from fossil fuels would be collected and stored in trees, underground formations, oceans and other potential reservoirs.
"Carbon capture and storage technologies can provide a bridge from today's fossil fuel based energy systems to the climate-friendly systems of the future. The technology exists today, but will not be adopted until there are economic incentives to reduce greenhouse gas emissions," said Herzog.
The team's analysis clearly delineates the advantages and limitations of each alternative power source. For example, replacing combustion engines with fuel-cell engines seems promising in cutting down the CO2 emissions from vehicles, but the study shows that the current process of producing the hydrogen required to power fuel cells actually creates more CO2 emissions than the combustion engines would create.
The report concludes: "Combating global warming by radical restructuring of the global energy system could be the technology challenge of the century ? Although regulation can play a role, the fossil fuel greenhouse effect is an energy problem that cannot be simply regulated away."
Other researchers collaborating on the project were from Columbia University, Exxon Mobil Research and Engineering Co., Lawrence Livermore National Laboratory, McGill University in Canada, NASA, the National Center for Atmospheric Research, the Naval Research Laboratory, the University of Arizona, the University of California at Irvine, the University of Houston and the University of Illinois at Urbana-Champaign. The project was funded in part by the U.S. Department of Energy.
A version of this article appeared in MIT Tech Talk on November 6, 2002.