给定一篇文章和一个主题，要求计算文中与该主题相关的单词占总单词数的百分比。


Article: In recent years, climate change has become a pressing issue. Many scientists argue that the earth is warming at an alarming rate, and that human activity is the primary cause. Some of the effects of climate change include rising sea levels, more frequent and severe weather events, and damage to ecosystems. Theme: climate change
可以先将文章中所有单词提取出来，然后计算其中与主题「climate change」相关的单词数量，并除以总单词数，得到相关单词占总单词数的百分比。