The oxidation in the self - portrait was probably caused by extreme humidity or a closed environment — consistent with the documented history of the piece. (newscientist.com)
«We know that our temperatures are rising; we're going to be experiencing more hot days but also more extreme humidity days, which tend to be a major driver of our extreme heat events,» Kelly Muellman, sustainability program coordinator at the city of Minneapolis, told GreenBiz. (pearltrees.com)