The Impacts of Freight Trade on Carbon Emission Efficiency: Evidence from the Countries along the “Belt and Road”
Table 2
Variable and definition.
Variable
Name
Definitions
Desired output
GDP
GDP of each country, converted to GDP calculated at the 1990 price using the GDP deflator
Undesired output
CO2
CO2 published by the World Bank
Input variable
Capital
Capital formation, converted to capital at 1990 prices using PPI
Labor
Average annual employment
Energy
Total energy consumption
Dependent variable
LCTCEI
Take natural logarithm after adding 1 to CTCEI
LITCEI
Take natural logarithm after adding 1 to ITCEI
LGTCEI
Take natural logarithm after adding 1 to GTCEI
LBPR
Take natural logarithm after adding 1 to BPR
LTGR
Take natural logarithm after adding 1 to TGR
Core Variable
LIFT
Take the natural logarithm after adding 1 to the ratio of total import and export volume to the current year’s freight volume (air freight volume and rail traffic volume)
Intermediary variable
LFDI
Take the natural logarithm after adding 1 to the ratio of FDI stock to GDP that year
Control variable
LRED
Take the natural logarithm after adding 1 to the ratio of government expenditure to GDP
LRFE
The ratio of the fossil energy consumption (coal, oil and natural gas) to the total energy consumption is increased by 1 to take the natural logarithm
LPatent
Take the natural logarithm after adding 1 to the ratio of the total number of patent applications to the number of employees in that year
LRID
Take the natural logarithm after adding 1 to the ratio of industrial added value to GDP
