Species across land, rivers, and seas decimated as humans kill for food in unsustainable numbers and destroy habitats
- The Guardian, Monday 29 September 2014 18.00 EDT
Creatures across land, rivers, and the seas are being decimated as humans kill them for food in unsustainable numbers, while polluting or destroying their habitats, the research by scientists at World Wildlife Fund and the Zoological Society of London found.
“If half the animals died in London zoo next week it would be front page news,” said Professor Ken Norris, ZSL’s director of science. “But that is happening in the great outdoors.
This damage is not inevitable but a consequence of the way we choose to live.” He said nature, which provides food and clean water and air, was essential for human wellbeing.
“We have lost one half of the animal population and knowing this is driven by human consumption, this is clearly a call to arms and we must act now,” said Mike Barratt, director of science and policy at WWF.
He said more of the Earth must be protected from development and deforestation, while food and energy had to be produced sustainably.
The number of animals living on the land has fallen by 40% since 1970.
From forest elephants in central Africa, where poaching rates now exceed birth rates, to the Hoolock gibbon in Bangladesh and European snakes like the meadow and asp vipers, destruction of habitat has seen populations tumble.
Marine animal populations have also fallen by 40% overall, with turtles suffering in particular.
Hunting, the destruction of nesting grounds and getting drowned in fishing nets have seen turtle numbers fall by 80%.
A second index in the new Living Planet report calculates humanity’s “ecological footprint”, ie the scale at which it is using up natural resources.
Currently, the global population is cutting down trees faster than they regrow,
catching fish faster than the oceans can restock,
pumping water from rivers and aquifers faster than rainfall can replenish them,
and emitting more climate-warming carbon dioxide than oceans and forests can absorb.
The report concludes that today’s average global rate of consumption would need 1.5 planet Earths to sustain it.
But four planets would be required to sustain US levels of consumption, or 2.5 Earths to match UK consumption levels.
The fastest decline among the animal populations were found in freshwater ecosystems, where numbers have plummeted by 75% since 1970.
“Rivers are the bottom of the system,” said Dave Tickner, WWF’s chief freshwater adviser. “Whatever happens on the land, it all ends up in the rivers.” For example, he said, tens of billions of tonnes of effluent are dumped in the Ganges in India every year.
As well as pollution, dams and the increasing abstraction of water damage freshwater systems. There are more than 45,000 major dams – 15m or higher – around the world.
“These slice rivers up into a thousand pieces,” Tickner said, preventing the healthy flow of water.
While population has risen fourfold in the last century, water use has gone up sevenfold. “We are living thirstier and thirstier lives,” he said.
“If humanity wishes to preserve a planet similar to that on which civilization developed and to which life on Earth is adapted, paleoclimate evidence and ongoing climate change suggest that CO2 will need to be reduced from its current levels of 398 ppm to at most 350 ppm…” – Dr. James Hansen
Since Dr. James Hansen, a leading climatologist, warned in 2008 that we need to reduce the amount of CO2 in the Earth’s atmosphere to 350 parts-per-million (ppm) in order to preserve life on Earth, little has been done to get us there.
It’s getting late. If we’re going to preserve a livable Earth we, the global grassroots, must do more than mitigate global warming.
We must reverse it.
Hint number one: not by politely asking out-of-control corporations and politicians to please stop destroying the planet.
Hint number two: not by pinning our hopes for survival and climate stability on hi-tech, unproven and dangerous, “solutions” such as genetic engineering, geoengineering, or carbon capture and sequestration for coal plants.
Hint number three: not by naively believing that soon (or soon enough) ordinary consumers all over the planet will spontaneously abandon their cars, air travel, air conditioning, central heating, and fossil fuel-based diets and lifestyles just in time to prevent atmospheric concentrations of greenhouse gases from moving past the tipping point of 450 ppm or more of CO2 to the catastrophic point of no return.
We can reverse climate change by sequestering several hundred billion tons of excess CO2 using the “tools” we already have at hand: regenerative, organic farming, ranching and land use.
And we can make this world-changing transition by mobilizing a vast green corps of farmers, ranchers, gardeners, consumers, climate activists and conservationists to begin the monumental task of moving the Carbon Behemoth safely back underground.
Ithaca, N.Y.—It may not kill them outright, but low-level PCB contamination is disrupting the way some birds sing their songs. So conclude the authors of a seven-year Cornell University study published today in the science journal PLOS ONE.
Before the chemicals were banned in the United States in 1979, polychlorinated biphenyls, or PCBs, were widely used in the manufacture of electrical devices because they can withstand extremely high temperatures.
“PCBs are changing behavior in subtle but important ways that we’re only beginning to recognize,” says lead author Sara DeLeon. “The Black-capped Chickadees and Song Sparrows we studied ingest PCBs when they eat contaminated insects. The chemicals appear to mimic hormones and interfere with development in the part of the bird’s brain that governs song and song structure.”
Key among the findings is that song disruption is tied to specific types of PCBs—there are 209 variations, differentiated by the positioning and number of chlorine atoms. DeLeon tested 41 of these variations to isolate their effects.
DeLeon chose five study sites in New York State, including two along the Hudson River that were heavily polluted by PCBs dumped illegally from 1947 to 1977. The other sites were not known to have PCB contamination and tests at an Adirondack Mountains site eliminated mercury as a factor in song changes. At each site she collected and tested blood samples from males of the two bird species, recorded their songs over several field seasons, and analyzed those songs.
“The songs of Black-capped Chickadees and Song Sparrows are very well studied,” DeLeon says. “For example, we know that it’s normal for there to be very, very little variation in the way all Black-capped Chickadees deliver their fee-bee song and the interval between the two notes.
We found the greatest variation among birds in areas with higher levels of certain types of PCBs—their songs just were not coming out right. Since dominant males produce the most consistent songs, this variation could have important biological consequences.”
It took about three years just to complete the chemical analyses.
The next logical step, Dhondt notes, would be to use this method to study low-level PCB effects elsewhere to learn how the pollutants are being spread through ecosystems and the effects they could be having.
Other co-authors include research associate Ralph S. Hames; assistant professor of ecology and evolutionary biology André Kessler; and Timothy DeVoogd, professor of psychology, all from Cornell.
This study was funded by: New York Sea Grant; Cornell University Biogeochemistry and Environmental Biocomplexity Small Grant; Cornell Travel Grant; Mellon Grant; Kieckhefer-Adirondack Grant; State University of New York Fellowship; SLOAN Fellowship; and a Tibor T. Polgar Fellowship.
Joseph Decker (1853 – 1924)