Carbon Neutral by 2050? Can It Be Done?
A carbon capture pilot plant in Wisconsin tested an advanced chilled ammonia process demonstrating more than 90% capture of carbon dioxide (CO2) from the flue stream of a coal-fueled power plant.
A new NASA analysis of global surface temperature shows 2009 tied for the second warmest year in modern record, according to the Goddard Institute for Space Studies in New York City. At the same time, a new public opinion poll confirms that the American public believes in climate change less.
Yale and George Mason universities released a survey last month showing that just 57% of people said global warming "is happening." ("Global warming" was the term used in the study.) That's down 14 percentage points, from 71%, in October 2008. Only 50% of people said they were "very" or "somewhat" worried about global warming, down 13 points from 2008.
The Intergovernmental Panel on Climate Change (IPCC), however, has made a definitive case for action. The IPCC says that stabilizing atmospheric CO2 concentrations will require a reduction of global greenhouse gas (GHG) emissions by as much as 80% by 2050… and that's just to avoid temperature increases of more than 2.5º C. The Minnesota state legislature adopted that strategic goal with its 2007 Next Generation Energy Act establishing reduction goals of 15% by 2015, 30% by 2025, and 80% by 2050 compared with 2005 levels.
Politics and "public resolve" aside, can it be done? Could we cut emissions to 80% of 2005 levels, or even become completely carbon neutral by 2050?
A tall order, but that's what the Ecosystem Science and Sustainability Initiative at the University of Minnesota looked at, understanding that such efforts will inform policy. In JR546, Olabisi et.al., in Reducing Greenhouse Gas Emissions for Climate Stabilization: Framing Regional Options (2009), offered a portfolio of strategies that would reach or surpass that goal.
To accomplish it, researchers say, policymakers would need to take aggressive conservation measures. But the answer to our initial question is yes, it can be done, and likely with negative net costs—meaning it'll actually save money.
State GHG Levels Are High
Minnesota, a cold-weather state, emits a disproportionate share of the world's greenhouse gas (GHG).
In 2003, per capita GHG emissions were four times the global average. The total emissions growth rate (1990-2003) was 56% higher than global rates. Under business as usual, GHG emissions in Minnesota would rise 49% over 2005 levels to 223 million metric tons of CO2 by 2050.
Sectors that contribute three-quarters of Minnesota's GHG emissions are: electricity, fuel for personal vehicles, agricultural, and energy used in residential and commercial buildings.
Olabisi et al. (2009)
According to the study, a combination of strategies and technologies can help us reach the 80% goal, though not all are politically or economically feasible.
In Minnesota, driving is more carbon-intensive than electricity consumption. Reducing vehicle miles traveled in the state to 1999 levels (by 2050), would mitigate the need for Minnesota to adopt as many other carbon-saving strategies. Reducing vehicle miles driven in Minnesota, however, might lead to spillover effects such as increased bus traffic, which were not analyzed in this study.
Also, if the state's transportation and electricity needs were met entirely through biomass production by 2050, the land footprint of these fuels—especially if grown in monocultures—would affect nutrient loss, water cycling, and aquatic/terrestrial wildlife habitat, and would overlap with lands currently used for producing food and forest products. Wind energy would have a much lower impact.
Unexpected technological innovations were not included in this study, but even so, the implementation of renewable and sequestration technologies, combined with strong conservation efforts, can result in major GHG reductions, even in carbon-intensive states like Minnesota.
To view the full report, log on to: http://pubs.acs.org/doi/abs/10.1021/es801171a.
|Scenarios that would get us there … or almost.|
|Reduction Potential below 2005 levels||Scenario (Technical Combination)|
|95% or virtually
|Convert all Minnesota electricity to poplar biomass with sequestering of carbon emitted at the plants; plus reduce vehicle-miles-driven by half; also improve fuel efficiency to 55 miles per gallon (m.p.g.); and reforest 5% of Minnesota's land.|
|90%||Convert all Minnesota electricity to poplar biomass with sequestering of carbon emitted at the plants; plus adopt 55-m.p.g. fleet fuel efficiency (fleet = cars and light trucks).|
|90%||Convert all Minnesota electricity to poplar biomass with sequestering of carbon emitted at the plants; plus convert all motor gasoline vehicles to switchgrass ethanol.|
|43%||Convert fossil-fuel electricity to wind electricity and switch from motor gasoline to cellulosic ethanol for personal vehicles. [This beats the Kyoto protocol, but is still well below the 80% goal.]|
|18%||Reduce commercial and residential electricity use; improve vehicle fleet fuel efficiency to 55 m.p.g.; and reduce vehicles-miles-driven by half. [18% below 2005 levels is still 45% below business-as-usual trajectory.]|
By Nancy Hoene