Mass Extinctions Change the Rules of Evolution
EXTRACT: Enough pieces have come together for Alroy to speculate on his findings’ implication for the future, given that Earth is now experiencing another mass extinction. Starting with extinctions of large land animals more than 50,000 years ago that continued as modern humans proliferated around the globe, and picking up pace in the Agricultural and Industrial ages, current extinction rates are far beyond levels capable of unraveling entire food webs in coming centuries. Ecologists estimate that between 50 and 90 percent of all species are doomed without profound changes in human resource use.
See Also:
9 Environmental Boundaries We Don’t Want to Cross
EXTRACT: Also exceeded are limits for species loss, which the scientists set at 10 per year per million species, and nitrogen use, pegged at 35 million tons per year. The current extinction rate is ten times higher than advised, ostensibly compromising the ability of ecosystems to process nutrients. The use of nitrogen — which is needed for fertilizer, but causes oxygen-choking algae blooms — is nearly four times higher than recommended.
