It turns out that the t-shirt slogan that "plants and animals die to make room for your (and my) fat ass" is true.
A new study published in the internationally recognized journal Science by my friend Dr. Stuart Pimm and colleagues has determined that the current rate of species extinctions is more than 1,000 times greater than the background rate calculated from the fossil record and genetic data, spanning millions of years. The primary cause of this dramatic rise in the loss of species is human population growth and increased consumption, according to the study.
The study confirms that species are going extinct at a pace not seen in tens of millions of years, and unlike past extinction events, the cause is us.
We've already lost so many species, including the passenger pigeon, Ivory-billed woodpecker, Steller's sea cow, sea mink and many more. Now that the crisis is speeding up, we wait in dread for the next species to disappear. What species will it be--the polar bear, American wolverine, Hawaiian monk seal or some other unique plant or animal never to be seen again?
The study uses newly available data on species distributions and imperilment to quantify the current extinction rate, which was estimated to be at least 100 extinctions per million species-years.
The researchers then analyzed extensive data on rates of speciation and extinction over millions of years to estimate a background or natural rate of extinction of .1 extinctions per million species-years, leading to the new estimate that we have increased the rate of extinction by at least 1,000 times.
For some taxonomic groups, extinction rates are even higher. North American freshwater fish, for example, were found to be going extinct at a rate of 305 extinctions per million species-years, or more than 3,000 times greater than the background rate, and the continent's snails and slugs are going extinct at a rate nearly 10,000 times background. These high rates reflect the degree to which we have degraded rivers and lakes in North America with dams, pollution, spread of non-native species and direct destruction.
The study's estimate of the current, devastating extinction rate is considered conservative because of the large number of species still unknown to science, the fact that a majority of such species are likely to be rare and at risk, and uncertainties in predicting future extinctions given increased habitat destruction, spread of invasive species and diseases, and global warming.
On a more hopeful note, the study also found that efforts to protect areas is making a difference, finding that the rate at which mammals, birds and amphibians are moving toward extinction over the past four decades would have been 20 percent higher were it not for efforts to protect places from harmful human activities.
Clearly, if we're going to save more species, we need to protect more places, curb our population growth (right now we're adding 227,000 more every day to the more than 7 billion people already on the planet), and reduce our consumption through smarter choices. Some may ask why we would need to go on a diet of such epic proportions.
The answer is simple. The loss of species has drastic consequences for us all by degrading ecosystems that clean our air and water, pollinate our crops and moderate the climate, by limiting potential new sources of food and medicine, and by making our world less interesting and lonelier.
After all, we depend on the very same things that all of these species that are dying do--namely water to drink, air to breath and space to carry out our daily lives. The fact that we're losing species at such an alarming rate daylights the degree to which we're degrading this planet that has nurtured us and should serve as a clear warning that our own future quality of life is in danger.