在認定農業能生產出農產品之外的其他各式多元有價值的舒適美質之前提下,「綠色給付」或許是一個能使農業此一產業達到福利最大的工具。在本文,我論述的主要重點是,如果沒有得到正確的綠色價格將帶來福利的損失,同時也會產生貿易扭曲。而無法監控綠色生產所造成貿易扭曲的惡化,將全面反應在農民對便宜的棕色與昂貴的綠色生產技術之間做選擇。因此,獲得正確的綠色價格與有效監控綠色生產是極其重要的。然而,價格評估工作必須能區分不同型態之美質舒適、品質及可親近性的需求者,而評估之架構要能由單一面向之美質擴及多面向,且要由區域擴及全國的空間範疇。當前,環境評估社群原則上可為農業所產生之相關舒適美質的願付價值提供良好的估計,但未來努力的方向應擴大過去所嘗試過的層面。最後,為達成福利最大,同時使貿易扭曲最小,需要將綠色價值之目標鎖定在農場上。
Given that agriculture produces a broad array of valuable amenities in addition to commodity outputs, ”green payments” might be a tool for maximizing welfare from the agricultural enterprise. Here, I argue that getting the green prices wrong would entail welfare losses and trade distortions; and that failure to monitor green production would exacerbate trade distortions in the all-too-common case where farmers are choosing between two commodity production technologies, brown and cheap or green and more expensive. So, it is important to get the green prices right and to monitor green production. The valuation task requires making some fine distinctions in terms of amenity type, quality, and accessibility to demanders; and the valuation framework must be consistent as we move from single to multiple amenities and from local to continental spatial scales. The environmental valuation community is able in principle to provide good estimates of WTP for agriculturally-produced amenities, but the valuation task requires an effort on a larger scale than has yet been attempted. Finally, to approach the welfare optimum while minimizing trade distortions will require targeting green prices down to the farm level.