Effects of Global Climate Change on Nigerian Agriculture: An Empirical Analysis

ABSTRACT

This paper presents an empirical analysis of the effects of global warming on Nigerian agriculture and estimation of the determinants of adaptation to climate change. Data used for this study are from both secondary and primary sources. The set of secondary sources of data helped to examine the coverage of the three scenarios (1971-1980; 1981-1990 and 1991-2000). The primary data set consists of 900 respondents’ but only 850 cases were useful. This study analyzed determinants of farm-level climate adaptation measures using a Multinomial choice and stochastic-simulation model to investigate the effects of rapid climatic change on grain production and the human population in Nigeria. The model calculates the production, consumption and storage of grains under different climate scenarios over a 10-year scenery. In most scenarios, either an optimistic baseline annual increase of agricultural output of 1.85% or a more pessimistic appraisal of 0.75% was used. The rate of natural increase of the human population exclusive of excess hunger-related deaths was set at 1.65% per year. Results indicated that hunger-related deaths could increase if grain productions do not keep pace with population growth in an unfavourable climatic environment. However, Climate change adaptations have significant impact on farm productivity.

INTRODUCTION

There is a growing consensus in the scientific literature that in the coming decades the world will witness higher temperatures and changing precipitation levels. The effects of this will lead to low/poor agricultural products. Evidence has shown that climate change has already affecting crop yields in many countries (IPCC, 2007; Deressa et al, 2008; BNRCC, 2008). This is particularly true in low-income countries, where climate is the primary determinant of agricultural productivity and adaptive capacities are low (SPORE, 2008; Apata et al, 2009). Many African countries, which have their economies largely based on weather-sensitive agricultural productions systems like Nigeria, are particularly vulnerable to climate change (Dinar et al, 2006). This vulnerability has been demonstrated by the devastating effects of recent flooding in the Niger Delta region of the country and the various prolonged droughts that are currently witnessed in some parts of Northern region. Thus, for many poor countries like Nigeria that are highly vulnerable to effects of climate change, understanding farmers’ responses to climatic variation is crucial, as this will help in designing appropriate coping strategies.

Evidence from literature and past studies has revealed that the recent global warming has influenced agricultural productivity leading to declining food production (Kurukulasuriya & Mendelsohn, 2006; IISD, 2007; Lobell et al, 2008). In order to meet the increasing food and non-food needs due to population increase, man now rapidly depleting fertile soils, fossil groundwater, biodiversity, and numerous other non-renewable resources to meet his needs (Abrahamson, 1989; Ehrlich & Ehrlich, 1990). This resource depletion was linked with other human pressures on the environment. Possibly the most serious of human impacts is the injection of greenhouse gases into the atmosphere. The reality of the impact of climate change on agricultural development has started showing signs (Adams et al, 1988; Fischer et al, 2002; Spore, 2008). A substantial body of research has documented these wide-ranging effects on many facets of human societies (Wolfe et al, 2005; ODI, 2007; Apata et al, 2009.).

Rough estimates suggest that over the next 50 years or so, climate change may likely have a serious threat to meeting global food needs than other constraints on agricultural systems (IPCC, 2007; BNRCC, 2008). Specifically, population, income, and economic growth could all affect the severity of climate change impacts in terms of food security, hunger, and nutritional adequacy. If climate change adversely affects agriculture, effects on human are likely to be more severe in a poorer world. Wolfe et al (2005); Stige, (2006), and Orindi et al, (2006) worry that rising demand for food over the next century, due to population and real income growth, will lead to increasing global food scarcity, and a worsening of hunger and malnutrition problems particularly in developing countries.

Recently, international tensions and concerns are heightening over what the impact of climate will have on the environment and agricultural produce (NEST, 2004; BNRCC, 2008; Apata, et al 2009). Also, how agricultural and food-distribution systems will be further stressed up by the shifting of temperatures and precipitating belts, especially if changes are rapid and not planned for (NEST, 2004). The crucial issue in this study is whether agricultural output supply can keep pace with population increase under this climate variability. This will depend; both on the scope for raising agricultural productivity (including reducing waste during distribution), availability of inputs used in the agricultural sector (land, labour, machinery, water resources, fertilizers, etc.) and having sufficient information on climatic variables for possible effective adaptation and mitigation strategies.

Consequently, attempt is being made in this study to investigate the effects of climate change on food demand and production as well as population increase in Nigeria. Past studies that have examined the impact of climate change on food production at the country, regional, or global scale (such as: Pearce et al. 1996; McCarthy et al. 2001; Parry et al. 2004; Nkomo et al, 2006; Stern 2007; Deressa, et al, 2008; BNRCC, 2008; Apata et al, 2009), have failed to provide critical insights in terms of effective and future adaptation strategies, although insights from these studies created the background for the present study.

 Studies on the impact of climate change (particularly rainfall and temperature) and climate- related adaptation measures on crop yield are very scanty. Studies by Liu et al, (2004) Mendelsoln et al, (2004), De-wit et al (2006), Kurukulasuriya & Mendelsohn, (2006), Deresa (2007), Yesuf et al (2009) and Apata et al (2009) are some of the economic studies that attempt to measure the impact of climate change on farm productivity. These studies imputed the cost of climate change as a proxy for capitalized land value and which are captured from farm net revenue. However, while these studies were conducted using sub-regional agricultural data as well as household-level it did not identify the determinants of effective adaptation methods to predict efficient adaptive measures. Also, its likely future effects on food production and population growth were not assessed. . Consequently, the objectives of this study are to examine effects of key climatic variables on food production and its likely effect on population increases and to identify the determinants of effective adaptation methods to predict efficient adaptive measures in a typical developing country, using household-specific survey data from Nigeria.