Estimates of earlier temperatures made from data such as ice cores and tree rings, though not as reliable as thermometers, suggest the decade may have been the warmest in the past millennium.

• 早期的气温数据是根据冰芯和树木年轮估算出来的，虽然不如温度计那么准确，但我们依然可看到，过去的十年是一千年来气温最高的十年。