From 1970 to 2010, Earth lost over 50 percent of its vertebrate wildlife population. This means we've lost over half of our birds, amphibians, reptiles, fish and mammals.
A 2014 study following the way animals that are considered important, like elephants, fish and tigers, change over time, showed there was a 52 percent decline in their numbers.
The situation is alarming, according to an emerging explorer at National Geographic. In the video below, the explorer, Shah Selbe, expands on what has caused the drop and if it were possible to reverse humans' effect on these populations.
"It's not until we see the impact that it has on the environment [and] the impact that it has on other species that we start to think twice about what we're doing," Selbe said in the YouTube video.
"You have to believe that we can make a difference," he added. "It's not a lost cause."
Cover photo credit: Gowild.wwf.org.uk