"This study concludes we better not exceed the 50 per cent mark of wholesale transformation of Earth’s surface or we won’t be able to delay, never mind avert, a planetary collapse. We’ve already reached the 43 per cent mark through our conversion of landscapes into agricultural and urban areas, making Earth increasingly susceptible to an environmental epidemic."
I'm guessing this really means the land surface of the Earth, rather than the Earth's surface as a whole, as ~70% of the Earth's surface is water. Without access to the paper itself, I can't say whether or not this is an issue with the "media release" or the research itself, of course.