但再无冰块漂浮的北冰洋并不仅仅是全球暖化的表象，它们也将是进一步暖化的成因：须知冰和雪都是可以反射太阳光线的。
But ice-free arctic waters are more than a symptom of global warming. They are themselves a cause of further warming: ice and snow reflect the sun’s rays.