How biodiversity loss is quietly eroding the potential for life-saving drug discovery
Even our ancient ancestors had medicines to turn to when they felt under the weather. The Egyptians, for example, would strip the leaves and bark from willow trees to ease their aching joints. Drawing on nature to cure ailments stretches back further than this, but with our destruction of the environment continuing apace some are concerned how much of it we'll have to depend on in the future.
The reason the Egyptians kept turning to the willow tree for healing was because of an active ingredient within it called salicylic acid, later noted by the Greek physician Hippocrates for its ability to relieve fevers and pain. Fast forward two or three thousand years and humans still rely on salicylic acid to make themselves feel better, but in the form of a synthetic adaptation called acetylsalicylic acid, better known as aspirin.
Modern science gives us the ability to tweak the chemistry of compounds like this in search of more powerful drugs, and even build them from scratch, but nature continues to be a huge source of drug discovery. In fact, the World Wildlife Fund says that of all small molecule drugs introduced in the last 25 years, at least 70 percent were derived natural sources.
Many come from plants, fungi and bacteria, but the animal kingdom also has a part to play. Within the last year alone, we've found a compound in the venom of the funnel-web spider that ruthlessly killed off skin cancer cells in the lab, an antibiotic candidate in rattlesnake venom that could prove vital in the fight against superbugs, and learned lessons in pest control from a parasitic vine. Just last week, scientists discovered a compound in a rare moss called liverwort with hugely promising anti-inflammatory properties.
Then there's the great potential of insects, which creep and crawl over every kind of terrain on the planet and could teach us how to build better hearing aids or cure Parkinson's disease. And mussels, with a tendency to bind to underwater surfaces that can inspire advanced surgical glues, and the ability of porcupine quills to easily penetrate a victim's skin, inspiring research into new kinds of hypodermic needles.
You get the idea.
Thank you and goodbye
This week the World Wildlife Fund (WWF) released its Living Planet report, an assessment of humanity's impact on the health of the Earth. The most striking figures relate to a remarkable decline in global wildlife populations over the past four decades. Human activity, driven largely by a growing demand for energy and food, has wiped out 60 percent of all mammals, birds, fish and reptiles since 1970.
Scientists contend that we are in the midst of a mass extinction event, the sixth in our planet's history, only this time around it is us, homo sapiens, that is to blame. Because we don't know how many million species are out there, it is difficult to calculate how many go extinct each year, but experts say the rate of loss is between 1,000 and 10,000 times higher than it would be if humans weren't around.
Consider this. In 1980 scientists studying a set of 19 trees in Panama were surprised to discover 1,200 different beetle species living within them, 80 percent of which were previously unknown to science. Meanwhile, we've chopped down 20 percent of the Amazon in the last 30 years.
Simon Elsässer is a research fellow in the Department of Medical Biochemistry and Biophysics at Sweden's Karolinska Institutet, and last year co-authored an article in the Journal of Global Health outlining the threats brought on by diminishing biodiversity. He says that, while the loss of animal species described in the WWF report is "alarming," it is only a taste of what we're really losing out on through environmental degradation.
"For each thousand of animal and plant species well-assessed to date, there are millions of single-cell organisms populating our planet, from the deepest sea to the highest mountain," he tells New Atlas. "We have not even a rough estimate of the diversity that lies in these simple but important organisms, and we must assume it is in extremely rapid decline given the widespread severe pollution of water and air."
Of all the global health problems we face heading into the future, antibiotic resistance is as big as they come. This refers to the ability for bacteria to evolve resistance to our very best antibiotics, effectively rendering them useless. Some experts worry that if no action is taken, superbugs could kill 10 million people a year by 2050, in essence returning us to the dark ages of medicine. For Elsässer, the looming threat of superbugs is reason enough to protect our bounty of yet-to-be-discovered natural molecules.
"We absolutely rely on the ingenuity of millions of years of evolution manifested in the millions of small organisms that coexist and compete with each other," says Elsässer. "Only a systematic research in the molecular biodiversity of our planet will provide us with new drug families that may be able to avoid an antibiotic resistance crisis."
Dr Ross Piper is an author, zoologist, BBC wildlife presenter and research fellow at the UK's Royal Geographical Society. He writes of a hormone in the saliva of a venomous lizard called the gila monster, which produces insulin to keep the animal's blood glucose levels in check.
A synthetic version of this hormone called exenatide is now used to treat type 2 diabetes and hauled in US$767 million worth of sales in 2014. The gila monster, meanwhile, is classified as near-threatened as a result of climate change and habitat loss stemming from real estate development in the American southwest. No money from the sale of exenatide has made its way back to the conservation of the species.
There are countless examples of how nature can contribute to the health and well-being of humans, but how many gila monsters, willow trees and liverwort mosses will we lose before we even get a chance to know them? Backed by millions of years of evolutional problem-solving, nature holds in front of us a molecular catalog that we're yet to even start turning the pages on – but we're tearing them out and burning them to keep warm instead.
"We've barely scraped the surface because there are so many species out there, probably billions of species alone," Piper tells New Atlas. "Historically it's been very difficult to obtain sufficient quantities of the material to allow characterization, and we have the arrogance to assume that combinatorial chemistry can do better than more than three billion years of evolution."
Safeguarding the future?
All of this paints a disconcerting picture of how rapid diversity loss is depleting our future stocks of life-saving medicines. Technology and science is improving all the time, but the way things are going we simply won't have the same pool of resources to draw inspiration from, or the same variety of natural mechanisms to study in our efforts to overcome illness and disease.
Unsurprisingly, scientists like Piper and Elsässer argue for greater efforts to protect biodiversity, through more funding for research programs that return money to human communities in biodiversity hotspots, in effect encouraging a sustainable relationship between us and particularly vital swathes of the Earth.
"We believe that the public, policy makers and entrepreneurs have to realize the enormous societal costs associated with rapid loss of biodiversity," says Elsässer. "We must acknowledge that climate change, global loss of diversity and the antibiotic resistance crisis are not three isolated risks, but, in fact, are symptoms of the same global problem, the irresponsible and unsustainable exploitation of natural resources."
In the view of Piper, nothing short of a dramatic rethink on how we approach things like food will really be effective in solving the problem of biodiversity loss.
"The biosphere is in a lot of trouble," he says. "The evidence is everywhere, from precipitous declines in insect diversity to enormous coral-bleaching events. In the short term we must end industrial agriculture and the enormous inputs of fertilizers and pesticides it requires. This will require breaking the grip of the agro-chemical companies. We need to create huge protected zones in the ocean that are completely off-limits to fishing and mining. In the medium term we need to drastically reduce our consumption of meat. In particular, beef production is a woefully inefficient use of land and causes huge amounts of habitat loss. Likewise, the soya production to feed all of these domesticated animals is a huge issue."
There are many threads tying the well-being of the environment to that of the human species, from the preservation of freshwater supplies, to the maintenance of fertile soil, to the carbon-sucking and air cleansing capabilities of forests. But is there a more explicit connection with environmental destruction and our own mortality than destroying the massive stores of medicines that might one day save our lives?