Final answer:
Current rates of extinction are significantly higher than those experienced in the past 100,000 years, with current estimates indicating a rate that is 500-1000 times the background extinction rate.
Step-by-step explanation:
Current rates of extinction may be higher than those of the past 100,000 years. Biologists have estimated that present-day extinction rates are 500-1000 times higher than the background rate of extinction. This alarming increase is attributed to human activities and is projected to cause significant declines in global biodiversity, threatening many species with extinction, including those not yet described by science. The background extinction rate is estimated at 1 per million species years (E/MSY), but recent estimates suggest a contemporary rate closer to 100 E/MSY, and this may rise to 1500 E/MSY by the end of the century.