今年二月二十九日，美國普渡大學發表的一項研究表明，如果轉基因生物GMO在美國被禁止，結果將會是：食品價格升高，改變土地使用用途引起溫室氣體排放量的顯著增加，以及森林和牧場土地的主要喪失。

農業經濟學教授Tyner說 “這不是一個要還是不要轉基因的爭論，這其實是一個簡單的問題：如果沒有轉基因世界將會怎樣？”

根據他們收集的數據進行的研究結果顯示，2014年在全世界28個國家有1800萬的農民種植了約1億8100萬公頃 （注：1公頃=2.471英畝=10000平方米）的轉基因作物，其中大約40% 的轉基因作物在美國種植。

他們使用用來檢測農業，能源，貿易和環境政策的改變對經濟影響的模型GTAPBIO分析這些資料。

模型顯示在美國去除GMO，玉米產量平均下降11.2%，黃豆減產5.2%，棉花減產18.6%。要彌補這些損失，必須將大約102000公頃的美國森林和牧場改變成耕地和全球平均1.1百萬公頃。

由於較低的作物產量，必須從牧場和森林轉換更多的土地用於農業生產，溫室氣體排放量會顯著增加。

換句話說，這些如果在美國限製GMO導致的溫室氣體排放量的增加將會超過創造足夠的土地以達到聯邦強製的關於150億生物燃料的需求量。

“一些同樣反轉基因食品組織要求減少溫室氣體的排放以減低全球變暖的可能，”Tyner說。“我們得到的結果是二者不能兼得。如果你想要在農業方麵減少溫室氣體排放，一個重要的工具就用是轉基因來達到。”

根據研究，如果沒有轉基因導致作物產量降低，商品價格上升。玉米價格將會增加28%，黃豆價格增加22%。預計每年的食品價格增加140-240億美元。

在美國每年種植轉基因產品幾乎占所有玉米（89%）、大豆（94%）和棉花（91%）。一些國家已經禁止轉基因產品，有些國家正在考慮禁止。農業經濟學教授Tyner和農業經濟學研究副教授 Taheripour說他們將繼續他們的研究以搞清楚在全球範圍內擴大和減少GMO作物會如何影響經濟和環境。

詳細信息可參考：

http://www.purdue.edu/newsroom/releases/2016/Q1/study-eliminating-gmos-would-take-toll-on-environment,-economies.html

原文摘要：

Evaluation of Economic, Land Use, and Land Use Emission Impacts of Substituting Non-GMO Crops for GMO in the US

Farzad Taheripour, Harry Mahaffey, and Wallace E. Tyner

Farzad Taheripour is Research Associate Professor, Harry Mahaffey is a MS student, and Wallace E. Tyner is James and Lois Ackerman Professor in the Department of Agricultural Economics at Purdue University

The main objective of this study was to evaluate what would be the economic and environmental consequences of losing the GMO traits in the U.S. for the major crops of corn, soybeans and cotton. The first step was to obtain from the literature a range of estimates of the yield losses if we move away from GMO traits in the U.S. The second step was to introduce the yield losses obtained in the first step into a well known CGE model, GTAP-BIO, to quantify the land use and economic impacts of banning GMO traits in the U.S. Our analysis confirms that if we do not have access to the GMO technology, a significant amount of land would need to be converted from other crops, cropland pasture, pasture and forest to meet the global food demand. The land expansion likely is similar to the entire U.S. ethanol program. Furthermore, induced land use emissions were significantly larger that the corresponding figure for corn ethanol. The price changes for corn were as high as 28% and for soybeans as high as 22%. In general, the price increases for the reference and average cases were higher than those observed previously for biofuel shocks. Food price changes in the U.S. amount to $14-$24 billion per year. As expected, welfare falls both in the U.S. and globally.