This wouldn't be the first time Earth's species have seen such a loss - over the past 3.5 billion years, more than 95 percent of species have vanished. This die-off is alarming because of both its speed and its attribution to humans (the other five extinctions were caused by astronomical or geological events).
But scientists don't know enough about species, in general, to anticipate the effects of this die-off is that. The Nature report says that estimates of the total number of species of animals, plants and fungi alive right now vary from 2 million to more than 50 million. And the added uncertainty of the effects of climate change presents another variable, according to Nature:
Looking forward, the picture gets less certain. The effects of climate change, which are hard to forecast in terms of pace and pattern, will probably accelerate extinctions in as-yet unknown ways.
"In general, the state of biodiversity is worsening, in many cases significantly," Derek Tittensor, a marine ecologist with the United Nations Environment Programme's World Conservation Monitoring Centre, told Nature.