The Kyoto Protocol, the developed world's effort to reduce greenhouse gas emissions relative to their 1990 levels, has largely failed. Only the UK and Germany have managed to reduce their emissions, in part due to the implementation of market mechanisms via a cap-and-trade system.
The US has increased emissions 16% since 1990 and China and India, while not precisely covered by the Kyoto Protocol, have been increasing emissions and are together with the US the biggest three polluters. The International Energy Agency predicts that China will surpass the US as the world's largest carbon dioxide emitter in 2009.
What is the lowest handing fruit in the US for reducing emissions?
Petroleum is responsible for the majority of worldwide greenhouse gas emissions. Of the four energy-using sectors; transportation, industrial, commercial and residential, transportation contributes a disproportionately large share of the US's carbon dioxide emissions. The chart below from the US Department of Energy shows expected emissions by sector and fuel type.
Industrial and Commercial Sectors not appropriate to address
According to Stanford energy economist and policy advisor, James Sweeney, the industrial sector has a complex energy usage mix and is not the best area to address first. Commercial energy use, with an emphasis on fluorescent lighting, is also not an obvious area for initial pursuit since the sector is one of the most efficient.
Transportation restructuring - the biggest impact
The single biggest impact on reducing US carbon dioxide emissions would be a redesign of motor vehicles, in particular, incorporating more stringent fuel efficiency requirements and redefining “truck” to not apply to passenger vehicles such as PT Cruisers, SUVs, etc.
Residential sector - additional gains
In the residential segment, a substantial improvement in energy efficiency can be gained by switching from incandescent bulb lighting to compact fluorescent bulb lighting. It appears likely that California and other forward-thinking states will pass compact fluorescent lighting legislation and that more efficient mercury-free bulbs will be introduced in the next few years.