A September 2009 study published by the Bank analyzes the factors responsible for transport sector CO2 emissions growth in selected developing Asian countries during 1980–2005.

The report, by Govinda R. Timilsina & Ashish Shrestha, can be downloaded from the Bank web site and is entitled “Why Have CO2 Emissions Increased in the Transport Sector in Asia? Underlying Factors and Policy Options” 

The analysis splits the annual emissions growth into components representing economic development; population growth; shifts in transportation modes; and changes in fuel mix, emission coefficients, and transportation energy intensity.

The study also reviews existing government policies to limit CO2 emissions growth, particularly various fiscal and regulatory policy instruments.

National CO2 emissions in Vietnam have increased from 14 million tons of C in 1980 to 80 in 2005 and the transport sector’s share of those emissions has almost doubled from 14% to 25%.

In 2005, looking at different transportation modes, road transport accounted for the bulk of C emissions with 91.95%; other modes were air (2.5%), water (4.8%), and rail (0.8%).

The study finds that of the six factors considered, three—economic development, population growth, and transportation energy intensity—are responsible for driving up transport sector CO2 emissions in Vietnam.

This was also true for Bangladesh and the Philippines.

Transportation energy efficiency is the ratio of total fuel consumption for transportation in an economy to its gross domestic product.

This value has slowly started to decline in Vietnam starting in about 1996, i.e., fuel consumption for transportation has declined per unit of economic output.

However, of the 11 countries in southeast Asia for which data are presented, Vietnam has the second highest transportation energy inefficiency, trailing only Malaysia.

In effect, the high inefficiency of fuel consumption relative to economic output in Vietnam contributes to its rapid growth in CO2 emissions from the transport sector.

In contrast, only economic development and population growth are responsible in the case of China, India, Indonesia, Republic of Korea, Malaysia, Pakistan, Sri Lanka, and Thailand.

CO2 emissions exhibit a downward trend in Mongolia due to decreasing transportation energy intensity.

The study also finds that some existing policy instruments help reduce transport sector CO2 emissions, although they were not necessarily targeted for this purpose when introduced.

This paper—a product of the Environment and Energy Team, Development Research Group—is part of a larger effort to study climate change and clean energy issues.