Wire the thermometers up to trigger off an alarm bell if the temperature drops.
把温度计的电线连接上，当温度下降时，就会触发警报。
《柯林斯英汉双解大词典》
2
Nobody knows for sure what might trigger it, but preventing a global temperature increase of more than 2 degrees Celsius is considered essential.
没有人确切知道哪些因素可能触发它，但防止全球气温上升超过2摄氏度被认为至关重要。
3
From the scientific perspective, the total of all these offers falls far short of what is required to keep the temperature rise below 2c and the catastrophic changes that could trigger.