Planetary boundaries is the central concept in an Earth system framework proposed by a group of Earth system and environmental scientists led by Johan Rockström from the Stockholm Resilience Centre and Will Steffen from the Australian National University. In 2009, the group proposed a framework of “planetary boundaries” designed to define a “safe operating space for humanity” for the international community, including governments at all levels, international organizations, civil society, the scientific community and the private sector, as a precondition for sustainable development. This framework is based on scientific research that indicates that since the Industrial Revolution, human actions have gradually become the main driver of global environmental change. The scientists assert that once human activity has passed certain thresholds or tipping points, defined as “planetary boundaries”, there is a risk of “irreversible and abrupt environmental change”. The scientists identified nine Earth system processes which have boundaries that, to the extent that they are not crossed, mark the safe zone for the planet. However, because of human activities some of these dangerous boundaries have already been crossed, while others are in imminent danger of being crossed.
The nine boundaries are
- Climate change *
- Biodiversity loss *
- Biogeochemical - nitrogen and phosphorous
- Ocean acidification
- Land use
- Ozone depletion
- Atmospheric aerosols
- Pollution *
Assessing the Environmental Impacts of Consumption and Production United Nations Environment Programme; 2010
Environmental impacts are the unwanted byproduct of economic activities. Inadvertently, humans alter environmental conditions such as the acidity of soils, the nutrient content of surface water, the radiation balance of the atmosphere, and the concentrations of trace materials in food chains. Humans convert forest to pastureland and grassland to cropland or parking lots intentionally, but the resulting habitat change and biodiversity loss is still undesired. The environmental and health sciences have brought important insights into the connection of environmental pressures and ecosystem damages. Well-known assessments show that habitat change, the overexploitation of renewable resources, climate change, and particulate matter emissions are amongst the most important environmental problems. Biodiversity losses and ill health have been estimated and evaluated. This report focuses not on the effects of environmental pressure, but on its causes. It describes pressures as resulting from economic activities. These activities are pursued for a purpose, to satisfy consumption. Environmental pressures are commonly tied to the extraction and transformation of materials and energy. This report investigates the production-materials-consumption nexus.
World Scientists’ Warning to Humanity: A Second Notice William J. Ripple, Christopher Wolf, Thomas M. Newsome, Mauro Galetti, Mohammed Alamgir, Eileen Crist, Mahmoud I. Mahmoud, William F. Laurance, 15,364 scientist signatories from 184 countries; BioScience; 1 Dec 2017
Twenty-five years ago, the Union of Concerned Scientists and more than 1700 independent scientists, including the majority of living Nobel laureates in the sciences, penned the 1992 “World Scientists’ Warning to Humanity” (see supplemental file S1). These concerned professionals called on humankind to curtail environmental destruction and cautioned that “a great change in our stewardship of the Earth and the life on it is required, if vast human misery is to be avoided.” In their manifesto, they showed that humans were on a collision course with the natural world. They expressed concern about current, impending, or potential damage on planet Earth involving ozone depletion, freshwater availability, marine life depletion, ocean dead zones, forest loss, biodiversity destruction, climate change, and continued human population growth. They proclaimed that fundamental changes were urgently needed to avoid the consequences our present course would bring.
The authors of the 1992 declaration feared that humanity was pushing Earth's ecosystems beyond their capacities to support the web of life. They described how we are fast approaching many of the limits of what the biosphere can tolerate without substantial and irreversible harm. The scientists pleaded that we stabilize the human population, describing how our large numbers—swelled by another 2 billion people since 1992, a 35 percent increase—exert stresses on Earth that can overwhelm other efforts to realize a sustainable future (Crist et al. 2017). They implored that we cut greenhouse gas (GHG) emissions and phase out fossil fuels, reduce deforestation, and reverse the trend of collapsing biodiversity.
On the twenty-fifth anniversary of their call, we look back at their warning and evaluate the human response by exploring available time-series data. Since 1992, with the exception of stabilizing the stratospheric ozone layer, humanity has failed to make sufficient progress in generally solving these foreseen environmental challenges, and alarmingly, most of them are getting far worse (figure 1, file S1). Especially troubling is the current trajectory of potentially catastrophic climate change due to rising GHGs from burning fossil fuels (Hansen et al. 2013), deforestation (Keenan et al. 2015), and agricultural production—particularly from farming ruminants for meat consumption (Ripple et al. 2014). Moreover, we have unleashed a mass extinction event, the sixth in roughly 540 million years, wherein many current life forms could be annihilated or at least committed to extinction by the end of this century.
15,000 Scientists From 184 Countries Are Warning Humankind We Are Screwed Stephen Leahy; Vice / Motherboard; 13 Nov 2017
More than 15,000 scientists from 184 countries warn the evidence is clear: Current and future human health and wellbeing are at serious risk from climate change, deforestation, loss of access to freshwater, species extinctions, and human population growth.
Eminent scientists Jane Goodall, E.O. Wilson, and James Hansen are among those who have cosigned the warning, published Monday in the journal BioScience. The article, titled “World Scientists' Warning to Humanity: A Second Notice,” has 15,372 signatories in total, from a range of scientific disciplines. It is thought to be the largest-ever formal support by scientists for a journal article.
The “Second Notice” article updates the original “World Scientists' Warning to Humanity” document released in 1992, 25 years ago this month. Signed by 1700 scientists, including most of the living Nobel Prize science winners, it warned that human impacts on the environment were putting “at serious risk the future that we wish for human society” and detailed several worrisome trends.
WE’VE CHANGED A LIFE-GIVING NUTRIENT INTO A DEADLY POLLUTANT. HOW CAN WE CHANGE IT BACK? Elizabeth Grossman; ENSIA; 25 Mar 2016
Coastal dead zones, global warming, excess algae blooms, acid rain, ocean acidification, smog, impaired drinking water quality, an expanding ozone hole and biodiversity loss. Seemingly diverse problems, but a common thread connects them: human disruption of how a single chemical element, nitrogen, interacts with the environment.
Nitrogen is absolutely crucial to life — an indispensable ingredient of DNA, proteins and essentially all living tissue — yet it also can choke the life out of aquatic ecosystems, destroy trees and sicken people when it shows up in excess at the wrong place, at the wrong time, in the wrong form. And over the past century, people have released so much of this type of nitrogen — known as reactive nitrogen — that scientists say we’ve passed the limit of what the planet can safely handle.
Can the World Find Solutions to the Nitrogen Pollution Crisis? Fred Pearce; Yale Environment 360; 6 Feb 2018
The world is using nitrogen fertilizer less and less efficiently. A greater proportion than ever before is washing into rivers and oceans. An environmental catastrophe looms, nitrogen scientists say, and the world urgently needs to develop strategies to prevent it.
Post-war physicists fearing nuclear apocalypse came up with the Doomsday Clock. In the 1980s, biologists contemplating ecological meltdown began talking about “biodiversity” loss as a way to tag and measure the crisis. Soon after, climate scientists recast concern over global warming with a warning that within a century it would lead to temperatures greater than any in human history.
Now, it is nitrogen’s turn.
Last month, in a seminar room at New York University, a score of nitrogen experts from around the world began drawing up scenarios of what a future nitrogen-soaked planet might look like – and to devise simple metrics for encouraging a global effort to head off disaster.
They met as part of the International Nitrogen Management System, a five-year, $60-million research project from the UN Environment Programme and the Global Environment Facility, that is intended, says its chief Mark Sutton, as nitrogen’s equivalent to the Intergovernmental Panel on Climate Change.
The bottom line, many there concluded, was that we must halve the amount of nitrogen we dump into the environment by mid-century or our ecosystems will face epidemics of toxic tides, lifeless rivers, and dead oceans. And that to do that will require, among other things, almost doubling the efficiency of nitrogen use on the world’s farms.
Freeze-thaw effects on phosphorus loss in runoff from manured and catch-cropped soils Bechmann ME, Kleinman PJ, Sharpley AN, Saporito LS; Journal of Environmental Quality; Nov 2005
Concern over nonpoint source P losses from agricultural lands to surface waters in frigid climates has focused attention on the role of freezing and thawing on P loss from catch crops (cover crops). This study evaluated the effect of freezing and thawing on the fate of P in bare soils, soils mixed with dairy manure, and soils with an established catch crop of annual ryegrass (Lolium multiflorum L.). Experiments were conducted to evaluate changes in P runoff from packed soil boxes (100 by 20 by 5 cm) and P leaching from intact soil columns (30 cm deep). Before freezing and thawing, total P (TP) in runoff from catch-cropped soils was lower than from manured and bare soils due to lower erosion. Repeated freezing and thawing significantly increased water-extractable P (WEP) from catch crop biomass and resulted in significantly elevated concentrations of dissolved P in runoff (9.7 mg L(-1)) compared with manured (0.18 mg L(-1)) and bare soils (0.14 mg L(-1)). Catch crop WEP was strongly correlated with the number of freeze-thaw cycles. Freezing and thawing did not change the WEP of soils mixed with manures, nor were differences observed in subsurface losses of P between catch-cropped and bare soils before or after manure application. This study illustrates the trade-offs of establishing catch crops in frigid climates, which can enhance P uptake by biomass and reduce erosion potential but increase dissolved P runoff.
Leading Ocean Scientists Recommend Immediate, Coordinated Action Plan to Combat Changes to West Coast Seawater Chemistry Scripps Institution of Oceanography; 6 Apr 2016
Global carbon dioxide emissions are triggering permanent changes to ocean chemistry along the North American West Coast that require immediate, decisive action to combat.
That action includes development of a coordinated regional management strategy, concluded a panel of scientific experts including Andrew Dickson, a professor of marine chemistry at Scripps Institution of Oceanography at UC San Diego.
A failure to adequately respond to this fundamental change in seawater chemistry, known as ocean acidification, is anticipated to have devastating ecological consequences for the West Coast in the decades to come, the 20-member West Coast Ocean Acidification and Hypoxia Science Panel warned in a comprehensive report unveiled April 4.
NASA Satellites Unlock Secret to Northern India's Vanishing Water NASA; 12 Aug 2009
Beneath northern India’s irrigated fields of wheat, rice, and barley ... beneath its densely populated cities of Jaiphur and New Delhi, the groundwater has been disappearing. Halfway around the world, hydrologists, including Matt Rodell of NASA, have been hunting for it.
Where is northern India’s underground water supply going? According to Rodell and colleagues, it is being pumped and consumed by human activities -- principally to irrigate cropland -- faster than the aquifers can be replenished by natural processes. They based their conclusions -- published in the August 20 issue of Nature -- on observations from NASA’s Gravity Recovery and Climate Experiment (GRACE).
"If measures are not taken to ensure sustainable groundwater usage, consequences for the 114 million residents of the region may include a collapse of agricultural output and severe shortages of potable water," said Rodell, who is based at NASA’s Goddard Space Flight Center in Greenbelt, Md.