Earth lost 10 percent of its pristine wilderness since 1993

How much wilderness is left on planet Earth? The answer to that question could determine a lot about how the globe bounces back from the effects of climate change, but the results of a new study do not paint a promising picture. While most conservation studies specifically document losses such as deforestation, conservation biographer James Watson has looked at the vanishing "wilderness" on the planet, which is "defined as pristine landscapes mostly free from human disturbances, including roads," Science writes.

Excluding "rock and ice" regions like Antarctica as well as oceans and lakes, Watson and his fellow researchers concluded that about 23 percent of the Earth was still wilderness by 2009, and most of that land is in North America, North Africa, North Asia, and Australia. Unfortunately, when comparing those numbers to 1993, researchers found that 10 percent of the Earth's wilderness areas have been destroyed in just two decades. Some regions have seen an even more devastating loss of pristine land, with South America losing 30 percent and Africa losing 14 percent of its wilderness in the 20-year period.

"This is the first time that anyone has put a number on the loss," Tim Newbold, a conservation biologist at University College London, told Science.

Part of the reason is because of the expansion of crop lands, pastures, night lighting, cities and urban areas, and railways; roadways and navigable waterways also take away from land, but haven't expanded significantly between the 1990s and 2000s. Although governments tend to protect severely threatened land, most wilderness on Earth is simply remote and not necessarily noticeably valuable, making it vulnerable to invasion by farmers or miners.

Watson's work is a startling "wake-up call," Robin Chazdon, an ecologist at the International Institute for Sustainability in Brazil, told Science.