Green bonds are a relatively new financial product that offers investors a variety of alternatives. However, many individuals continue to be suspicious about its long-term returns and risks. To clarify this issue, this study employed two global environment events—COP26 and COP27—to influence investor attention and investor yield of green bonds and conventional bonds. The data are collected from 15,188 bonds, including 779 green bonds and 14,409 conventional bonds issued from 2021 to 2023 worldwide. The event study method has been conducted with pre- and post-event data to estimate the impact of green bond issuance before and after COP26 and COP27 on investor returns, as well as the impact of investor attention on investment returns. The research results show that investors should buy shares of companies that issue green bonds after major environmental events to benefit from the higher CAR of these companies. Investors can also use the S&P 1200 index as a measure to assess risk and abnormal returns when making short-term investments in shares of organizations that issue green bonds.