Humans are ‘eating away at our own life support systems’ at a rate unseen in the past 10,000 years, two new research papers say
Oliver Milman The Guardian 15 Jan 15;
Humans are “eating away at our own life support systems” at a rate unseen in the past 10,000 years by degrading land and freshwater systems, emitting greenhouse gases and releasing vast amounts of agricultural chemicals into the environment, new research has found.
Two major new studies by an international team of researchers have pinpointed the key factors that ensure a livable planet for humans, with stark results.
Of nine worldwide processes that underpin life on Earth, four have exceeded “safe” levels – human-driven climate change, loss of biosphere integrity, land system change and the high level of phosphorus and nitrogen flowing into the oceans due to fertiliser use.
Researchers spent five years identifying these core components of a planet suitable for human life, using the long-term average state of each measure to provide a baseline for the analysis.
They found that the changes of the last 60 years are unprecedented in the previous 10,000 years, a period in which the world has had a relatively stable climate and human civilisation has advanced significantly.
Carbon dioxide levels, at 395.5 parts per million, are at historic highs, while loss of biosphere integrity is resulting in species becoming extinct at a rate more than 100 times faster than the previous norm.
Since 1950 urban populations have increased seven-fold, primary energy use has soared by a factor of five, while the amount of fertiliser used is now eight times higher. The amount of nitrogen entering the oceans has quadrupled.
All of these changes are shifting Earth into a “new state” that is becoming less hospitable to human life, researchers said.
“These indicators have shot up since 1950 and there are no signs they are slowing down,” said Prof Will Steffen of the Australian National University and the Stockholm Resilience Centre. Steffen is the lead author on both of the studies.
“When economic systems went into overdrive, there was a massive increase in resource use and pollution. It used to be confined to local and regional areas but we’re now seeing this occurring on a global scale. These changes are down to human activity, not natural variability.”
Steffen said direct human influence upon the land was contributing to a loss in pollination and a disruption in the provision of nutrients and fresh water.
“We are clearing land, we are degrading land, we introduce feral animals and take the top predators out, we change the marine ecosystem by overfishing – it’s a death by a thousand cuts,” he said. “That direct impact upon the land is the most important factor right now, even more than climate change.”
There are large variations in conditions around the world, according to the research. For example, land clearing is now concentrated in tropical areas, such as Indonesia and the Amazon, with the practice reversed in parts of Europe. But the overall picture is one of deterioration at a rapid rate.
“It’s fairly safe to say that we haven’t seen conditions in the past similar to ones we see today and there is strong evidence that there [are] tipping points we don’t want to cross,” Steffen said.
“If the Earth is going to move to a warmer state, 5-6C warmer, with no ice caps, it will do so and that won’t be good for large mammals like us. People say the world is robust and that’s true, there will be life on Earth, but the Earth won’t be robust for us.
“Some people say we can adapt due to technology, but that’s a belief system, it’s not based on fact. There is no convincing evidence that a large mammal, with a core body temperature of 37C, will be able to evolve that quickly. Insects can, but humans can’t and that’s a problem.”
Steffen said the research showed the economic system was “fundamentally flawed” as it ignored critically important life support systems.
“It’s clear the economic system is driving us towards an unsustainable future and people of my daughter’s generation will find it increasingly hard to survive,” he said. “History has shown that civilisations have risen, stuck to their core values and then collapsed because they didn’t change. That’s where we are today.”
The two studies, published in Science and Anthropocene Review, featured the work of scientists from countries including the US, Sweden, Germany and India. The findings will be presented in seven seminars at the World Economic Forum in Davos, which takes place between 21 and 25 January.
Humans push planet beyond boundaries towards "danger zone": study
Chris Arsenault PlanetArk 16 Jan 15;
Human activity has pushed the planet across four of nine environmental boundaries, sending the world towards a "danger zone", according to a study published on Thursday in the journal Science.
Climate change, biodiversity loss, changes in land use, and altered biogeochemical cycles due in part to fertilizer use have fundamentally changed how the planet functions, the study said.
These changes destabilize complex interactions between people, oceans, land and the atmosphere, said the paper "Planetary Boundaries: Guiding human development on a changing planet" by 18 leading international researchers.
Passing the boundaries makes the planet less hospitable, damaging efforts to reduce poverty or improve quality of life.
"For the first time in human history, we need to relate to the risk of destabilizing the entire planet," Johan Rockstrom, one of the study's authors and an environmental science professor at Stockholm University told the Thomson Reuters Foundation.
Scientists in 2009 identified and quantified the nine planetary boundaries within which humanity can develop and thrive.
The five other boundaries - ozone depletion, ocean acidification, freshwater use, microscopic particles in the atmosphere and chemical pollution - have not been crossed.
Passing the boundaries does not cause immediate chaos but pushes the planet into a period of uncertainty.
Scientists consider climate change the most serious crossed boundary.
The amount of carbon dioxide in the atmosphere, a gas causing the planet to warm, has exceeded 350 parts per million to the present 395 parts per million, crossing the boundary of what scientists think to be acceptable.
"We are at a point where we may see abrupt and irreversible changes due to climate change," Rockstrom said, as warming could cause Arctic ice sheets to melt releasing more greenhouse gases and creating a vicious feedback loop.
The study results are set to be incorporated into the new global development goals that will be finalised in September at the United Nations in New York to replace the Millennium Development Goals on poverty alleviation expiring this year.
Scientists hope the new study will help balance competing demands for economic growth and environmental sustainability which are likely to arise during the conference.
Despite a steady drumbeat of grim warnings, food prices have declined the past four years, indicating that wild weather linked to climate change is not destroying harvests worldwide.
Commodity prices, a measure of scarcity for energy and other basic goods, are also falling, leading some economists to question warnings from climate scientists and environmentalists.
"Just because we are not seeing a collapse today doesn't mean we are not subjecting humanity to a process that could lead to catastrophic outcomes over the next century," Rockstrom said.
(Editing by Alisa Tang.)
Climate change, extinctions signal Earth in danger zone: study
Alister Doyle Reuters Yahoo News 15 Jan 15;
OSLO, Jan 15 (Reuters) - - Climate change and high rates of extinctions of animals and plants are pushing the Earth into a danger zone for humanity, a scientific report card about mankind's impact on nature said on Thursday.
An international team of 18 experts, expanding on a 2009 report about "planetary boundaries" for safe human use, also sounded the alarm about clearance of forests and pollution from nitrogen and phosphorus in fertilisers.
"I don’t think we've broken the planet but we are creating a much more difficult world," Sarah Cornell, one of the authors at the Stockholm Resilience Centre which led the project as a guide to human exploitation of the Earth, told Reuters.
"Four boundaries are assessed to have been crossed, placing humanity in a danger zone," a statement said of the study in the journal Science, pointing to climate change, species loss, land-use change and fertilizer pollution.
Of a total of nine boundaries assessed, freshwater use, ocean acidification and ozone depletion were judged to be within safe limits. Others, including levels of airborne pollution, were yet to be properly assessed.
The report defined climate change and loss of species as two core areas of concern. Each "has the potential on its own to drive the Earth System into a new state should they be substantially and persistently transgressed," the authors wrote.
Rising concentrations of carbon dioxide, the main greenhouse gas, are about 397 parts per million in the atmosphere, above 350 ppm that the study set as the boundary for safe use.
Almost 200 governments will meet in Paris in late 2015 to try to agree a deal to limit global warming to avert floods, droughts, heatwaves and rising sea levels blamed on rising emissions of greenhouse gases.
The study said that rates of extinctions of animals and plants, caused by factors ranging from pollution to deforestation, were 10 to 100 times higher than safe levels.
"Transgressing a boundary increases the risk that human activities could inadvertently drive the Earth System into a much less hospitable state," said lead author Will Steffen, of the Stockholm Resilience Centre and the Australian National University, Canberra.
The report expanded definitions of the planetary boundaries set in 2009, making it hard to compare trends.
(Reporting by Alister Doyle; Editing by Mark Trevelyan)
