碳邊境稅之引力──台灣是否應課徵碳稅以應對歐盟碳邊境調整機制（CBAM）？

THE GRAVITY OF CARBON BORDER ADJUSTMENT TAXES: SHOULD TAIWAN IMPOSE A CARBON TAX IN RESPONSE TO EU CARBON BORDER ADJUSTMENT MECHANISM (CBAM)?

歐盟已開始試行碳邊境調整機制（Carbon Border Adjustment Mechanism，CBAM），其目的是透過貿易手段防止碳排放洩漏至環境標準較低的國家，從而推動全球氣候目標的實現。台灣作為全球貿易和供應鏈的核心，CBAM相關政策對於台灣的影響尤為關鍵。為了應對這一挑戰，台灣政府正加速推動碳定價政策。本研究建立了一個涵蓋多國、多產業的結構性引力模型，在模型中，碳定價與碳邊境稅會直接影響中間財的價格，且透過國際貿易與供應鏈引導資源配置，並進一步影響各國的碳排放。本文分析CBAM對台灣及全球各國經濟和環境的影響。模型運用了各國現行的碳定價，並結合CBAM實務上的執行方式，全面探討了CBAM的短期經濟效果、對國際市場價格的影響，以及其對資源配置、貿易趨勢、所得以及碳排放的引導作用。根據模型結果，我們計算出在應對CBAM衝擊時，使台灣全國實質所得損失最小的碳定價為每公噸二氧化碳16美元，這一數字遠高於目前環境部提出的每公噸二氧化碳10美元的碳費費率。然而，每公噸二氧化碳16美元應被視為台灣政府設定碳定價的最低標準，因為本研究的分析未涵蓋碳排放的外部性、長期影響以及能源轉型等其他因素。綜合考慮這些額外因素後，台灣需要課的碳價將高於每公噸二氧化碳16美元。

The European Union's Carbon Border Adjustment Mechanism (CBAM) aims to use trade measures to prevent carbon leakage to countries with lower environmental standards to achieve global climate goals. Taiwan, being a central hub in global trade and supply chains, could be particularly affected by CBAM-related policies. The Taiwanese government is thus accelerating the implementation of carbon pricing policies. We construct a structural gravity model with multiple countries and industries, where carbon pricing and border carbon adjustments directly affect prices of intermediate goods, which guides resource allocation through international trade and supply chains, further impacting carbon emissions across countries. We analyze the economic and environmental impacts of CBAM on Taiwan and other countries. Our model incorporates current carbon pricing across countries and integrates implementation of CBAM in practice to examine its economic effects on international prices and how it guides resource allocation, trade patterns, income, and carbon emissions. We reckon that the carbon price that minimizes Taiwan's national income loss in response to CBAM is USD 16 per tonne of CO2, significantly higher than the current carbon price of USD 10 per tonne discussed by Taiwan's Ministry of Environment. However, USD 16 per tonne should be considered a minimum for Taiwan's carbon pricing, as this analysis does not cover the externalities of carbon emissions, long-term impacts, and energy transition. Considering these additional factors, the appropriate carbon pricing for Taiwan should be higher.