Which animals could go extinct by 2050?

Five mass extinctions have happened in Earth’s history, and numerous experts have warned that a sixth mass extinction could already be underway as a result of human activity since the Age of Exploration. Some scientists have even suggested that nearly 40% of the species (opens in new tab) currently residing on our planet could be extinct as early as 2050.

But is this just a worst-case scenario? Is such a dramatic decline in Earth‘s species likely to happen?