Scientists think that such unseasonal temperatures are the result of both global warming and natural climate variability.

VOA: standard.2009.09.03

Plus, there are some natural metabolic variability and I'll describe that in a subsequent lecture.

另外,这里面有自然的新陈代谢差异,我会在随后的课堂上讲解

耶鲁公开课 - 关于食物的心理学、生物学和政治学课程节选