Programme  OS1d Tropical zones  abstract 613

Environmental Kuznets Curve for Irrigation and its Implications for Future Water Demands:

Author(s): a 20-years of Cross-Country Analysis for 65 Tropical countries
Contact address of the corresponding author Dr. Madhusudan Bhattarai Agricultural Economist P. O. Box 42, Shanhua, Tainan, Taiwan 74199, ROC Phone: (+886-6) 583-7801 Fax : (+886-6) 583- 0009 Email:

Keyword(s): Environmental Kuznets Curve for Irrigation, Irrigation Demand, Population Growth, Economic Development, Global Irrigation Modelling, Asia, Africa, Latin America, Cross-countries Analysis

Article: abs613_article.pdf
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Session: OS1d Tropical zones

This paper verifies an existence of the

Environmental Kuznets Curve (EKC) hypothesis for irrigation. The EKC hypothesis suggests for an inverse U-

shaped (or concave) relationship between the level of environmental degradation and income in a given society. It

also implies that some form of environmental deterioration appears inevitable during the initial stage of development,

but subsequent increases in the social income would generate enough incentives to improve the environmental quality.

In line with this reasoning, the EKC relationship for irrigation (referred to here as Irrigation Kuznets Curve, or IKC)

is hypothesized suggesting that the demand for irrigation is greater at the initial stage of development and that

irrigation demand declines as social income increases. This process subsequently gives rise to an inverted U-shaped

relationship between the level of irrigation and the level of income. This information on EKC for irrigation has large

implications on policy planning for irrigation and for analyzing demand for irrigation, and water uses and water

reallocations across sectors.


The major objective of this study is to empirically verify the

presence of the EKC relationship for irrigation and to illustrate its policy implications. Subsequently, it also evaluates:

i) the impact of selected macroeconomic policy, structural and governance related factors (population,

energy use, technological change) affecting the irrigation-income relationship across the countries;
ii) analyze

policy implications of the empirical findings on EKC for future demand for irrigation and demand for water

resources, in general.


In this study, the EKC hypothesis for irrigation (i.e., IKC) is examined

across 66 tropical countries from Asia, Africa and Latin America using national-level annual data from 1972 to

1991. The IKC model is once estimated for 66 tropical countries, and separately for 13 countries from Asia where

more than two-thirds of the global irrigated land is located. Two measures of irrigation are used, “percentage of crop

area irrigated” and “relative change in net irrigated area.” In addition to estimating irrigation and income relationship,

effects of other broad-level institutions and policy factors on irrigation are also analyzed such as governance (sum

total of political and civil liberty indices), cereal yield, agricultural value added, manufacturing value added growth,

rural population density, economic growth rate, and per capita electricity use.

Results, Conclusions, and

Policy Implications

The empirical results provide strong evidence for the existence of an EKC relationship for

the two measures of irrigation used, and for both the tropical-global and the Asia EKC models. This means that the

pace of irrigation development is faster at the initial stage of a country’s development and that it will be at a slower

rate at the later stage of development. The empirical findings also imply that there is no leapfrogging in the process of

irrigation and agricultural development and management of natural resources in an economy.
The non-linear

relationship (elasticity value) estimated between irrigation and a nation’s income has profound impacts for better

forecasting irrigated-area (and water demand) in an economy, as opposed to the zero-income elasticity of irrigation

assumed in most past studies. Irrigation area and water-demand analyses are so far mostly based upon per capita

requirement type of forecast-modeling technique, which ignores the underlying income effects and societal

substitutional behavior over resources use decisions as shown in IKC modeling here. The study findings contribute

significantly in global debates on water and assessment on future water needs.

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