【正确答案】 B

【答案解析】原文：For the first time ever, scientists have recorded the heart rate of the world’s largest creature: the blue whale. To get this reading, they attached an electrocardiogram device to the body of a whale. They found that the mammal’s heart rate can slow to just two beats a minute as the animal searches for food below the surface of the ocean. The highest heart rate they recorded was 37 beats a minute after the whale returned to the surface for air.题目问根据报道,是什么导致了气候紧急情况。新闻最后提到“It warns that the world would face‘untold human suffering’if it does not make deep and lasting shifts in human activities that influence climate change”，即科学家们发出警告,表示如果不深刻和持久地改变影响气候变化的人类活动,世界将面临“无尽的人类痛苦”。由此可见，人类活动造成了气候紧急情况，故选B。