Australia’s Kyoto Protocol ratification (KPR) in December 2007 mandates the country to reduce greenhouse gas (GHG) emissions, hence affecting firms in the highest emitting industries. We exploit the KPR as an exogenous increase in environmental risk facing the highest GHG emitters. We find that the stock market reactions to bank loan announcements significantly increase after the KPR for these emitters relative to non-emitters. The effect is stronger for borrowers with higher information asymmetry and financial constraints. The evidence suggests that banks can certify their borrowers’ environmental risk through their loan approvals, which confirms the certification role of banks.

澳大利亚于2007年12月批准了《京都议定书》（KPR），要求该国减少温室气体（GHG）排放，从而影响排放量最高的行业的公司。我们将KPR开发为面临最高温室气体排放者的环境风险的外源性增长。我们发现，与非发行人相比，这些发行人的KPR之后，股票市场对银行贷款公告的反应显着增加。对于具有更高信息不对称性和财务约束的借款人而言，这种影响更为强烈。有证据表明，银行可以通过批准贷款来证明其借款人的环境风险，从而证实了银行的证明作用。