Atmospheric Sciences & Global Change Division
Weaving a Common Thread
Research points to lowest-cost strategies to limit the effects of greenhouse gas emissions
Climate modeling research shows that society’s lowest cost option to reduce the heat-trapping effect of greenhouse gases is to use every available means to reduce emissions, including greater reliance on nuclear and renewable energy-generated electricity and expanding forests to naturally absorb and store carbon. Enlarge Image
Results: The least costly way to manage the heat-trapping effect of greenhouse gases in the atmosphere is to pursue every available option to reduce emissions, according to a study by Pacific Northwest National Laboratory, published in the journal Climatic Change. The study's authors point to a future with greater reliance on nuclear and renewable energy, reducing emissions through new technologies that capture and store carbon dioxide, and expanding forests to naturally absorb and store carbon.
Why it matters: The climate change decisions made by policy makers today will have significant consequences for future generations. The longer it takes to reduce greenhouse gas emissions, the more expensive it will be in terms of dollars and quality of life. This research is designed to identify society's most cost-effective strategy for dealing with climate change.
Methods: A global collaboration of scientists responded to a request from the Intergovernmental Panel on Climate Change, and generated a set of four scenarios to represent future greenhouse gas emissions and land use change. One of the four simulations was produced by scientists at the Joint Global Change Research Institute, a partnership of PNNL and the University of Maryland. All of the scenarios are now being applied by climate modelers around the world to understand how climate may respond to different levels of greenhouse gas emissions from human activities.
"It's very important that the climate community has a common thread of scenarios as a resource so that model results are comparable. It will help researchers collaborate in studies of how to respond to climate change," said Dr. Allison Thomson, PNNL scientist and the lead research author.
To better understand the range of possible futures, scientists modeled greenhouse gas generated from energy use and agricultural activities to the year 2100. PNNL's model scenario limits the heat-trapping effect of greenhouse gases in the atmosphere to levels only 65 percent of what they would reach if no future emissions controls are implemented.
Scientists used PNNL's Global Change Assessment Model to generate its scenario. GCAM uses market forces to reach a specified greenhouse gas emission target by allowing global economics to put a price on carbon. The model helps reveal the least costly way to achieve targets. Unlike other models, GCAM includes carbon stored in forests, causing forest acreage to increase even as energy systems change to include fuels generated from bioenergy crops and crop waste. The scenario began with 2005 conditions of greenhouse gas emissions, land use and technologies, and then allowed the model to simulate greenhouse gas emissions and land use changes until 2100.
In the PNNL scenario, the price of carbon stimulates growth in nuclear and renewable energy use. Also, it becomes cost-effective to implement technologies that capture and store emissions from fossil- and bio-fuel based electricity in underground reservoirs when carbon dioxide emissions to the atmosphere carry a cost. Buildings and industry become more energy efficient. From today's carbon dioxide emissions of 30 gigatons per year, levels will peak around the year 2040 at 42 gigatons annually. Emissions will then decrease steadily and level out after 2080 at around 15 gigatons per year.
For more information on this report, see PNNL's press release
What's next: PNNL scientists are now collaborating with international researchers to develop a common set of socio-economic scenarios. These will be used with the greenhouse gas emissions scenarios to provide a consistent data set for assessing how climate change may impact societies, and what can be done to adapt.
Acknowledgments: This research was funded by the Department of Energy Office of Science, Office of Biological & Environmental Research Integrated Assessment Research Program.
Reference: Thomson A, K Calvin, S Smith, P Kyle, A Volke, P Patel, S Delgado-Arias, B Bond-Lamberty, M Wise, L Clarke, and J Edmonds. 2011. "RCP 4.5: A Pathway for Stabilization of Radiative Forcing by 2100." Climatic Change. DOI: 10.1007/s10584-011-0151-4.