In terms of medicine, our most important modern pharmaceuticals, including quinine, morphine, aspirin, penicillin, and many other antibiotics, are derived from microbes, plants, and animals found in tropical and marine environments. The first comprehensive scientific treatise on our reliance on other species, Sustaining Life: How Human Health Depends on Biodiversity, published in 2008, confirmed the importance of genetic variety, describing groups of threatened organisms crucial to agriculture and human medicine. Predictably, our close relatives, primates, make up a key group. Contributing to work on smallpox, polio, and vaccine development, primates allow research on potential treatments for hepatitis C and B, Ebola and Marburg viruses, and HIV/AIDS.
The list of threatened plants and animals we rely on is weird and varied, including amphibians, bears, gymnosperms (the family of plants that includes pine trees), cone snails, sharks, and horseshoe crabs. Cone snails, a large genus of endangered marine mollusks, inject their prey with paralyzing toxins that are prized in medical research for their use in developing pain medications for cancer and AIDS patients who are unresponsive to opiates. The blood of the horseshoe crab, which carries antimicrobial peptides that kill bacteria, is being tested in treatments for HIV, leukemia, prostate cancer, breast cancer, and rheumatoid arthritis; it also yields cells crucial in developing tests to detect bacteria in medical devices, and its eyes have allowed Nobel Prize–winning researchers to unravel the complexities of human vision.
Cone snails and horseshoe crabs are exactly the kinds of species that people tend to dismiss, seeing no utility in them, no connection to human need. This was the attitude expressed in 1990 by Manuel Lujan Jr., secretary of the interior during the George H. W. Bush administration, who asked in exasperation, “Do we have to save every subspecies?” It was the attitude expressed in 2008 by presidential candidate John McCain, who repeatedly declared his opposition to the funding of research on grizzly bear DNA. He got a cheap laugh whenever he said, “I don’t know if that was a paternity issue or a criminal issue.” Medical researchers were not laughing: bears, too, are essential to human medicine. Bear bile yields ursodeoxycholic acid, now used in treating complications during pregnancy, gallstones, and severe liver disease. Denning bears enter a period of lethargy during the winter and recycle body wastes in a process unique in mammals; this process is studied for insights in treating osteoporosis, renal disease, diabetes, and obesity.
If species are crucial to medicine, ecosystems are indispensable to the health of the planet. Ecosystems provide the most basic provisioning services— food, firewood, and medicines—along with the so- called regulating services of a fully functional environment, which include cleaning the air, purifying water, controlling floods and erosion, storing carbon, and detoxifying pollutants in soils. When ecosystems are lost, as they have been through felling of forests and conversion of landscape to agriculture on a vast scale, havoc ensues, triggering human and natural catastrophe on an unprecedented scale.
Gradually, we are realizing that the environment is the economy. The planet’s rain forests currently function as a “giant ‘utility,’ ” according to Andrew Mitchell, director of the Global Canopy Program. He points out that the Amazon alone releases twenty billion tons of water into the atmosphere daily, providing free air-conditioning, free irrigation, free hydropower. With more tracts of rain forest lost every day, what will it cost to provide artificially the services we currently get for free? A recent study commissioned by the European Union calculates that those lost services, along with the massive release of carbon as forests go up in smoke (accounting for 20 percent of carbon emissions worldwide), add up to 7 percent of global GDP, or two to five trillion dollars annually— the equivalent of the total cost of the Iraq War every year.