The main alarmist assertion has been rebutted by @Botanygeek on twitter. I tend to turn to him whenever a newspaper reports on any environmental story, the same way we have to show scepticism every time a newspaper reports on any "x cures y" story.

Here are his thoughts in The New Scientist:

[1]: https://www.newscientist.com/article/mg24232291-100-the-idea...