تجزیه و تحلیل هزینه سود از یک درخواست دسترسی به واردات

Invasive species outbreaks are often unintended side effects of trade. In this paper partial equilibrium trade models and stochastic bioeconomic impact simulation models are combined to present a benefit cost analysis template to assess market access requests. The template is used to assess the likely regional economic welfare implications of a decision by Australian biosecurity regulators to allow the Chilean table grape industry access to the national table grape market. We show that consumption benefits expected to accrue to Western Australia are exceeded by increases in likely invasive species damage resulting from grape imports, implying that insufficient consumer gains are grounds to deny market access.

As the interconnectedness of trading economies throughout the world continues to increase, so too does the damage expected from invasive species incursions. While the opening up of new and lucrative trade pathways facilitated by the World Trade Organization (WTO) increase the abundance and variety of goods available to consumers, the international community must remain mindful of the potential damage caused as a result of biological contaminations. The damage caused by invasive species has been described as “immense, insidious, increasing and irreversible” (Sandlund et al., 1996). This has been highlighted through a combination of quantitative assessments like Pimentel et al. (2002) and anecdotal “horror stories” like those provided in Bright, 1998 and Baskin, 2002. Many species included in these assessments are thought to have occurred as a result of trade (Levine and D’Antonio, 2003). While resultant environmental damage is recognised in international agreements such as the Convention on Biological Diversity (1991), topographically and demographically disperse invasive species impacts typically prevent commodity markets from capturing all the costs associated with trade. It therefore falls to individual governments to consider the tradeoff between trade benefits and invasive species risk. Although this tradeoff is readily acknowledged (Snape and Orden, 2001 and Josling et al., 2004), research has tended to focus on one or the other. Whilst internationally net welfare analyses such as Petersen and Orden (2006) have been used to inform international trade policies, invasive species production impacts have tended to receive the majority of scholarly attention in the Australian context. This is due (in part) to their inclusion in the WTO’s Agreement on the Application of Sanitary and Phytosanitary Measures (henceforth termed the SPS Agreement) as relevant economic factors to consider in import risk assessments (GATT, 1994). Economic assessments of market access requests made to Australia have largely been absent from trade decisions apart from those concerning persistent requests from high-profile sources. Examples such as Bhati and Rees, 1996, McKelvie, 1991 and McKelvie et al., 1994 have focussed on specific quarantine decisions as opposed to the broader social welfare implications of policy options (Nunn, 2001 and Roberts, 2001). In contrast James and Anderson, 1998 and Cook and Fraser, 2002 have largely focused on the increased utility of consumers resulting from cheaper imports of agricultural commodities, and have been not explored consequent invasive species outbreaks in any detail. In this paper we answer the challenge of comparing both consumption gains and potential invasive species damage associated with a trade decision. We present a case study involving table grape imports into the State of Western Australia (WA) with the potential to act as a vector for the entry of a number of harmful invasive species of grapes. We suggest that in this particular instance allowing imports may result in production losses through invasive species damage of $10.3 million, and consumption benefits of only $1.5 million. All monetary values in the paper are expressed in Australian dollars unless otherwise specified.

The continued expansion of international trade brings with it both benefits to consumers and potential losses to producers as a result of invasive species incursions. Yet, there is little evidence of direct comparisons between them having been made in the context of a trade decision. This paper has used both consumer benefits and potential invasive species losses to perform a benefit cost analysis of importing table grapes to the State of WA. In quantifying potential invasive species damage that could result from trade, three of a larger list of species were used in the assessment. Our results suggest that the expected damages from these species are more than sufficient to offset the gains to consumers resulting from cheaper table grape imports. As a result, a decision to allow table grape imports is likely to produce a net loss in social welfare over time. In interpreting these results, it is important recognise that a closed-economy situation imposes a considerable cost to the economy in terms of forgone benefits to trade. Similarly, a quarantine-restricted trade setting also forgoes trade benefits, so moving from one setting to the other involves replacing one set of costs with another. In the case of the WA table grape industry, it is estimated that a closed-economy costs WA between and $3.8 million and $5.8 million annually in terms of foregone gains from trade. A quarantine-restricted market situation forgoes between $1.8 million and $4.9 million worth of gains from trade. Therefore, liberalising trade to allow table grapes to be imported subject to quarantine restrictions is expected to increase net economic welfare by between $1.0 million and $2.1 million. However, in opening up the market to trade, the domestic table grape industry is exposed to a higher level of biosecurity risk due to the presence of potentially harmful pests and diseases in external table grape sources. An examination of production and transport costs has revealed that imported table grapes are most likely to come from producers in the eastern States of Australia rather than Chile due to prohibitive transport costs. Therefore, invasive species affecting grapes that WA is likely to have increased exposure to include Queensland fruit fly, European red mite and Grapevine fanleaf virus. Combined economic impact simulation results for these pests indicate an average increase in expected damage (assessed over a 30-year period) of approximately $10.3 million per year. These estimates lead us to conclude that a net social welfare gain is unlikely to result from a decision to import table grapes to WA. The methodology we have presented is generally applicable to any agricultural trade issue, and simply provides an estimate of likely net benefits related to a specific volume of trade and specific SPS measures. We have demonstrated how a simple comparison of benefits and costs can call into question inter-regional and international trade decisions. Yet, until such an assessment becomes the focus of a WTO dispute settlement panel it remains to be seen if consumer benefits constitute a WTO-compliant justification for SPS restrictions. Certainly in terms of interstate trade in commodities like table grapes in Australia discussions of net welfare outcomes are set to intensify.