A major new study in the polar ice sheets has discovered that the rate of melting has accelerated in the past 20 years. David Shukman is our science correspondent.

有关极地冰原的重大研究表明，冰原的融化速度在过去20年间已经加速。科学记者David Shukman报道。

Warming above this point increases the risk of triggering major tipping points, including the death of coral reefs and the melting of polar ice sheets, which will add to sea level rise, devastating coastal communities.

全球变暖超过 1.5 度会增加多个重要临界点被触发的风险，包括珊瑚礁死亡和极地冰原融化，这会令海平面升高，给海岸居民带来毁灭性后果。