UN Framework Convention on Climate Change (UNFCCC)
Conferences of the Parties (COP)
UNFCCC 2015: COP 21 in Paris
CO2.Earth 2015: COP 21 in Paris
UNFCCC All COPs
Humanity's response to climate change and related global environmental problems involves many participants, and many kinds of participants. And there are many inter-connected parts to the response. CO2.Earth chunks the parts together into eight steps. The aim is to give individuals an entry point for comprehending the global scale of humanity's response.
Presenting the chunks as eight steps suggests a step-by-step sequence. Some sequencing exists but the reality is not that simple. There is a lot of looping back and jumping ahead. You may find that some aspects of humanity's response are missing. It's just a simplified description that makes it easier to understand the types of elements that make up humanity's response. The steps are listed below.
STEP 1 Problem Identification
STEP 2 Set Ultimate Objective
STEP 3 Stabilization Basics
STEP 4 World Engagement
STEP 5 World Targets
STEP 6 Transformative Changes
STEP 7 Stabilization Watch
Action is not enough. To be useful, actions should help the world energy and resource systems make a timely transition to sustainability for the short and long term. To know what helps and what doesn't, learn about earth systems and conditions lead to a stabilization of CO2 in the atmosphere. Learning opens up new vistas and pathways for transformation. It is a practical and critically-important step that individuals can take in response to climate change.
This short webpage introduces a small number of ideas and concepts that were chosen so they might inspire learning about the earth system, CO2 stabilization and related matters. Regardless of which sources of learning and transformation inspire you the most, consider making a deliberate decision to pursue learning about systems and stabilization.
Innovate to Zero
In 2010, BIll Gates gave a TED Talk, "Innovating to Zero." In the talk, he acknowledges advice he received from scientists on the inevitable need for global CO2 emissions to drop to zero. And it acknowledges the need to end global climate change in order to preserve humanitarian advances that are being seen in many other fields.
Gates' talk points to a particular response: 4th generation nuclear energy. The talk is not posted to promote this single prescription. It is not to promote technology as a standalone response to global environmental problems. The purpose is to promote the idea that people and societies have the capacity to advance human ingenuity and innovation to get to zero emissions. Regardless of your thoughts on the prescription Bill Gates is presenting, consider his talk as one good example of miixing purpose and innovation to develop pathways to outcomes as difficult as 'zero CO2 emissions.' Afterall, innovation reveals many pathways, including pathways that today seem unimaginable.
Divest from Fossil Fuels
Money talks. Money matters. Individuals and groups can influence change by making deliberate investment decisions. Moving money from fossil fuel infrastructure to alternative, carbon-free energy says a lot. You might say that it helps inject wisdom and intelligence into the market system. And that's a good thing, right?
Leading the way, students and educators around the world are persuading college and university administrations to move institutional money from fossil fuel investments--and make investments that align with a prosperous future.Consider this excerpt from an open letter signed by more than 300 faculty at Stanford University in California, USA:
If a university seeks to educate extraordinary youth so they may achieve the brightest possible future, what does it mean for that university simultaneously to invest in the destruction of that future?
~ 300+ Faculty at Stanford University
Stanford Faculty Divest 2015 letter to support fossil fuel divestment
Fossil Free Stanford Students pledge disobedience unless Stanford divests
Go Fossil Free Home Page | Learn how to divest in your part of the world
Rolling Stone McKibben (2013) The case for fossil-fuel divestment
Rolling Stone McKibben (2012) Global warming's terrifying new math
About 90% of global CO2 emissions comes from burning fossil fuels. If humanity is to achieve zero CO2 emissions and create a future without non-renewable fossil fuels, the global energy system requires transformation. Energy infrastructure needs to be replaced with infrastructure for renewables.
The Solutions Project (USA) Transition to 100% clean, renewable energy
Rising CO2 and other global environmental challenges involve complex earth and human systems. To comprehend the challenges and effective responses, it helps to think in systems. Many schools, teachers and resources are available to assist people while learning about systems. A very short, introductory list of resources is offered below. It is sure to grow over time.
Centre for EcoLiteracy Seven lessons for leaders in systems change
University of Oslo Transformation 2013 Conference Video & Proceedings
Pathways for Decarbonization
Rome wasn't built in a day. The development of any new system takes time. There are so many details, it is impossible to make all the decisions in advance. In these complex situations, a clear direction enhances effectiveness. Defining a pathway enables a shared sense of how advances are made. Climate response pathways are commonly discussed, and many options exist.
Aiming to mix ambition and practicality, the Deep Decarbonization Pathways Project (DDPP) is introduced as an approach that deserves consideration.
The DDPP is a collaborative initiative to understand and show how individual countries can transition to a low-carbon economy. It shows that the world can meet the internationally-agreed target of limiting global average surface temperature to less than 2°C. Avoiding this threshold means global net GHG emissions need to approach zero by the second half of the century. This will take a profound transformation of energy systems between now and 2050 through steep declines in carbon intensity throught the economy. The researchers call this transmortation “deep decarbonization.”
The DDPP publishes pathways for the world and 15 countries. The single link below takes you to the DDPP site and host of publications and tools for designing a tranformative pathway to decarbonization.
Deep Decarbonization Pathways Project DDPP Website
What environmental conditions must exist for earth's climate system to stabilize? CO2.earth presents a few basic concepts for understanding climate stabilization in an earth systems context. Consider the links here at Step 3 a possible starting place. It is far from comprehensive or finished.
Global Before Local
"We have a clearer picture of future climate changes on a global scale than of the local consequences associated with a global warming. And we know why."
~ Rasmus E. Benestad 2015 [info]
Local data is more variable and potentially at odds with overall global trends. It can tell us a lot, but global data can signal a planetary trend that can be clearer and more reliable than local signals.
RealClimate 2015 Climate change is coming to a place near you
CO2 Stabilization Prerequisites
The IPCC published a 'Frequently Asked Question' in 2007 that quantifies the changes in atmospheric stabilization for different greenhouse gasess based on the percentage of cuts made in global emissions from human sources. Based largely on that resource, the relationship between changes in CO2 emissions and changes in atmospheric CO2 is summarized below.
Emissions Changes vs. Atmospheric Changes
A 10% cut in global CO2 emissions will result in about a 10% cut in the growth rate for atmospheric CO2 concentrations. To stabilize atmospheric CO2 in either the short or long term, much deeper cuts are needed.
"A 50% reduction would stabilise atmospheric CO2, but only for less than a decade. After that, atmospheric CO2 would be expected to rise again as the land and ocean sinks decline owing to well-known chemical and biological adjustments. Complete elimination of CO2 emissions is estimated to lead to a slow decrease in atmospheric CO2 of about 40 ppm over the 21st century."
~ IPCC (2007, p. 824)
Short Term Stabilization
To understand why emissions need to be cut in half to achieve atmospheric stabilization, you will be learning about the airborne fraction for CO2 emissions from human sources. See the next tab for an introduction to this concept.
Long Term Stabilization
The reference above to "complete elimination of CO2 emissions" is not simply an idealized scenario. It is a prerequisite for long-term stabilization of CO2 concentrations in the atmosphere.
"Only in the case of essentially complete elimination of emissions can the atmospheric concentration of CO2 ultimately be stabilised at a constant level. All other cases of moderate CO2 emission reductions show increasing concentrations because of the characteristic exchange processes associated with the cycling of carbon in the climate system."
~ IPCC (2007, p. 824)
This information is critical for comprehending the level of emissions cuts needed to stabilize atmospheric CO2 and, practically speaking, global temperature and global climate as well.
Consequences of Delay
The Fifth Assessment report also states that cumulative CO2 emissions over time increase damages and possibilities of irreversible impacts.
"Substantial cuts in GHG emissions over the next few decades can substantially reduce risks of climate change by limiting warming in the second half of the 21st century and beyond. Cumulative emissions of CO2 largely determine global mean surface warming by the late 21st century and beyond. Limiting risks across RFCs would imply a limit for cumulative emissions of CO2. Such a limit would require that global net emissions of CO2 eventually decrease to zero and would constrain annual emissions over the next few decades."
~ IPCC (2014, p. 19)
To identify emissions prerequisites for stabilizing other greenhouse gases, see the IPCC's 2007 FAQ 10.3.
Scientific information about the stabilization of CO2 concentrations point to zero global CO2 emissions from human sources as a prerequisite for achieving and sustaining stabilized atmospheric CO2 levels for the long term.
Humanity has some choices to make.
One is whether or not it wishes to achieve stabilization. The signatures of 195 countries adopting the UN Framework Convention on Climate Change, Article 2 in particular, indicates that humanity made that choice in the 1990s. Our institutions opted to achieve stabilization.
The next choices are these:
- By what date or atmospheric levels will humanity achieve initial stabilization of CO2 and other GHGs (including a rapid global cut in human CO2 emissions of about 50%)?
- By what date or atmospheric levels will humanity achieve long-term stabilization of CO2 and other GHGs (via the elimination of human CO2 emissions).
Science Daily Stabilizing climate requires near-zero carbon emissions
Carbon Tracker Fossil fuels are dead. The rest is just detail.
See the next tab for an introduction to "airborne fraction."
IPCC. (2014). Climate change 2014: Synthesis report. Contribution of working groups I, II and III to the fifth assessment report of the Intergovernmental Panel on Climate Change. (Core Writing Team, R. K. Pachauri, & L. A. Meyer Eds.). Geneva, Switzerland: IPCC. [web + .pdf + Chinese + Korean]
Meehl, G. A., Stocker, T. F., Collins, W. D., Friedlingstein, P., Gaye, A. T., Gregory, J. M., . . . Zhao, Z.-C. (2007). Global climate projections. Frequently asked question 10.3: If emissions of greenhouse gases are reduced, how quickly do their concentrations in the atmosphere decrease? In S. Solomon, D. Qin, M. Manning, Z. Chen, M. Marquis, K. B. Averyt, M. Tignor, & H. L. Miller (Eds.), Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (pp. 824-825). Cambridge, UK and New York, USA: Cambridge University Press.
CO2 Airborne Fraction
Science Daily '09 Is the airborne fraction of anthropogenic CO2 increasing?
CO2.earth Global carbon emissions
Biogeosciences '15 Sitch et al. | Recent trends, regional CO2 sources and sinks [.pdf]
Nature Geoscience '09 Le Quéré et al. | Trends in the sources and sinks of CO2 [.pdf via GCP]
Canadell JG et al. (2007) Contributions to accelerating atmospheric CO2 growth from
economic activity, carbon intensity, and efficiency of natural sinks. PNAS 104:
Friedlingstein P, Houghton RA, Marland G, Hackler J, Boden TA, Conway TJ,
Canadell JG, Raupach MR, Ciais P, Le Quéré C. Update on CO2 emissions. Nature
Geoscience, Online 21 November 2010.
Le Quéré, C., Moriarty, R., Andrew, R. M., Canadell, J. G., Sitch, S., Korsbakken, J. I., . . . Zeng, N. (2015). Global carbon budget 2015. Earth System Science Data, 7(2), 349-396. doi:10.5194/essd-7-349-2015
Raupach MR et al. (2007) Global and regional drivers of accelerating CO2 emissions.
Proceedings of the National Academy of Sciences 14: 10288-10293.
Climate Change Inertia
Inertia in the climate system means that climate change and climate change impacts will continue for decades to centuries after source factors responsible for the changes are removed. Three types of inertia affecting the climate system are introduced below, along with the masking effect of aerosols.
This tab considers the following:
- committed CO2 emissions of existing infrastructure
- committed temperature and sea level increases from GHG emissions 'already in the atmosphere'
- prior warming masked by the cooling effect of aerosols that may decline
Even if humanity commits to a near-elimination of human-caused CO2 emissions, energy and transportation infrastructure have long lifespans that represent substantial CO2 emissions commitments for the next 50 years (Davis et al., 2010). This infrastructural inertia "may be the primary contributor to total future warming commitment" (p. 330).
In a hypothetical example where future CO2 emissions are limited to CO2-emitting devices that exist now, researchers estimate that those emissions (from 2010 to 2060) would allow a stabilization of atmospheric CO2 below 430 ppm and an average warming to reach about 1.3°C above pre-industrial levels. For comparison, scenarios that allow CO2-emitting infrastructure to expand resulted in warming of 2.4°C to 4.6°C by 2100 and atmospheric CO2 of more than 600 ppm.
Warming Locked In
Globally, warming of close to 1.5°C above pre-industrial times (up from about 0.8°C in 2014), is already locked into the earth system by past and predicted greenhouse gases (World Bank, 2014).
Need for Alternatives
The researchers note that CO2-emitting infrastructure that existed in 2010 was not enough to push atmospheric CO2 and global warming beyond guardrail targets of 450 ppm CO2 and 2°C. They caution that it is the CO2-emitting infrastucture not yet built that exposes the world to the most threatening climate impacts. Avoidance of this scenario requires extraordinary efforts to develop alternatives (Davis et al., 2010).
Climate Change Commitment
A number of climate studies have used models to run simulations that identify and quantify delayed climate changes and impacts in hypothetical stabilization scenarios. These studies enable scientists to learn how the earth can be expected to respond to a cessation of GHG emissions that warm the climate system, and of aerosols that mask some of the GHG warming. They show that the greatest inertia (delayed response) is found the oceans, and that some inertia is found global temperature levels.
For example, Meehl and his co-investigators (2006) created a hypothetical scenario where greenhouse gas concentrations in 2000 remained the same for the next 100 years. The multiple simulations they ran showed that "we are already committed to 0.4°C more global warming by the year 2100 compared to 0.6°C observed warming realized by the end of the twentieth century" (p. 2603). Further, temperature shows signs of levelling off 100 years after atmospheric GHG levels stabilize.
Sea level shows greater inertia than global temperature. Sea level increases rose more than double observed increases in the prior 100 years (1901 to 2000). By 2100, the 'Meehl simulations' show a continuing upward trend.
If the world suddenly stopped burning fossil fuels the first of January next year, atmospheric CO2 would quickly stabilize. But temperature and sea level would continue to increase increase long after. Scientists refer to this delayed stabilization of temperature and other climate impacts as "climate commitment."
A large fraction of climate change is largely irreversible on human time scales, unless net anthropogenic CO2 emissions
were strongly negative over a sustained period. See IPCC AR5, Ch 12, p. 1033.
Matthews and Zickfeld (2012) estimated that full elimination of aerosols results in warming of between 0.25°C and 0.5°C in the decade after their elimination.
Delayed responses already in the system heighten the urgency for taking immediate action to build and implement alternatives for CO2 and GHG-emittig infrastructure that are in use now.
Nature '05 Oceans extend effects of climate change
Davis, S. J., Caldeira, K., & Matthews, H. D. (2010). Future CO2 emissions and climate change from existing energy infrastructure. Science, 329(5997), 1330-1333. doi:10.1126/science.1188566
Friedlingstein, P., & Solomon, S. (2005). Contributions of past and present human generations to committed warming caused by carbon dioxide. Proceedings of the National Academy of Sciences of the United States of America, 102(31), 10832-10836.
Gillett, N. P., Arora, V. K., Zickfeld, K., Marshall, S. J., & Merryfield, W. J. (2011). Ongoing climate change following a complete cessation of carbon dioxide emissions. Nature Geoscience, 4(2), 83-87. doi:10.1038/ngeo1047
Meehl, G. A., Washington, W. M., Santer, B. D., Collins, W. D., Arblaster, J. M., Aixue, H., . . . Strand, W. G. (2006). Climate change projections for the twenty-first century and climate change commitment in the CCSM3. Journal of Climate, 19(11), 2597-2616.
Matthews, H. D., & Zickfeld, K. (2012). Climate response to zeroed emissions of greenhouse gases and aerosols. Nature Climate Change, 2(5), 338-341. doi:10.1038/nclimate1424
Wigley, T. M. L. (2005). The climate change commitment. Science, 307(5716), 1766-1769.
Cumulative carbon budget
IPCC on budget
Link to zickfeld on time for budget.
Link to GCP about budget used.
Policy choice = how much left to use
Huffington Post '15 Mann | How close are we to dangerous warming?
Source Image UNFCCC
Humanity has an ultimate objective to guide its response to climate change. The United Nations Framework Convention on Climate Change came into force on March 21, 1994 (UNFCCC). The 195 countries that ratified the UNFCCC are Parties to the Convention. By ratifying the UNFCCC, they each adopted an ultimate objective that is set out in Article 2:
The ultimate objective of this Convention and any related legal instruments that the Conference of the Parties may adopt is to achieve, in accordance with the relevant provisions of the Convention, stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system. Such a level should be achieved within a time-frame sufficient to allow ecosystems to adapt naturally to climate change, to ensure that food production is not threatened and to enable economic development to proceed in a sustainable manner.
The world has an ultimate objective, but is it clear what is needed? The simple conclusion is that 195 countries have agreed to stabilize the concentration of greenhouse gases at some point. But what is dangerous interference with the climate system?
The International Panel on Climate Change addressed this question in 2007 when it published its 4th Assessment Report. They review the findings of expert groups that asssociate uppper limits of risk at global average temperature increases of between 1ºC and 2ºC, and greehouse gas concentrations as high as 550 parts per million CO2-equivalent. The IPCC's AR4 focusses on key vulnerabilities that relate to Article 2: biological systems, social systems, geophysical systems, extreme events and regional systems. The IPCC article, What is dangerous interference with the climate system?, discusses the compleixities of this question in more detail.
Since 2007, some scientists have identified 350 ppm CO2 as an upper boundary, although increased radiative forcing of 1 watt per square meter of the earth is more comprehensive because it includes other greenhouse gases and all other human-caused factors (Hansen et al., 2008; Rockström et al., 2009; Steffen et al., 2015).
UNFCCC Text of the Convention (English) [PDF]
UNFCCC. First steps to a safer future: Introducing The United Nations Framework Convention on Climate Change. Retrieved October 5, 2015, from http://unfccc.int/essential_background/convention/items/6036.php [link]
Rio 1992 Earth Summit (Context)
Source UN Photo | Michos Tzavaros
The 1992 United Nations Conference on Environment and Development (UNCED)--commonly known as the Earth Summit--"was a watershed event in the history of international negotiations, laying, as it did, the foundation for a new global partnership to achieve sustainable development for all the world's peoples" (Cicin-Sain, 1996, p. 123). The conference resulted in five major agreements:
- Rio Declaration of Principles
- UN Framework Convention on Climate Change
- Convention on Biological Diversity
- Agenda 21
- A 'Statement on Forest Principles'
These agreements set out a vision for a more sustainable and equitable global society. They also pointed toward a road map for getting there. That is, they combined legal obligations for nations in the two conventions with a variety of 'soft law' principles, guidelines and prescriptions to guide nation-states and others on a wide range of environment and development issues.
In the decades since the 1992 Earth Summit in Rio de Janerio, follow-up actions and agreement have varied. As we look at the current landscape and future actions, it may be helpful to consider earlier perspectives and contexts that led to mechanisms like the UN Framework Convention on Climate Change. That is it is within this larger context that countries adopted the ultimate objective articulated in Article 2 of the UNFCCC.
Earth Summit (General)
Rio Declaration on the Environment
UNEP Agenda 21
IISD Agenda 21
Statement of Forest Principles
UN Framework Convention on Climate Change
UN Convention on Biological Diversity
Voice of a Child Delegate
"If you don’t know how to fix it, please stop breaking it!"
~ Severn Cullis-Suzuki (Age 12 at the 1992 Earth Summit)
Source YouTube / We Canada
ssjothiratnam.com Full text of Severn Suzuki's speech to UN Earth Summit
Cicin-Sain, B. (1996). Earth summit implementation: Progress since Rio. Marine Policy, 20(2), 123-143. doi:10.1016/S0308-597X(96)00002-4 [journal]
Sustainable Development Goals
On September 25, 2015, 193 member states of the United Nations unanimously adopted the new Sustainabe Development Agenda (2030 Agenda). At its core, this new agreement has 17 sustainable development goals.
SDG 'Goal 13' lends support for work undertaken through the UNFCCC by agreeing "to take urgent action to combat climate change and its impacts.*" SDG13 sets out the following targets:
13.1 Strengthen resilience and adaptive capacity to climate-related hazards and natural disasters in all countries
13.2 Integrate climate change measures into national policies, strategies and planning
13.3 Improve education, awareness-raising and human and institutional capacity on climate change mitigation, adaptation, impact reduction and early warning
13.a Implement the commitment undertaken by developed-country parties to the United Nations Framework Convention on Climate Change to a goal of mobilizing jointly $100 billion annually by 2020 from all sources to address the needs of developing countries in the context of meaningful mitigation actions and transparency on implementation and fully operationalize the Green Climate Fund through its capitalization as soon as possible
13.b Promote mechanisms for raising capacity for effective climate change-related planning and management in least developed countries and small island developing States, including focusing on women, youth and local and marginalized communities
* Acknowledging that the United Nations Framework Convention on Climate Change is the primary international, intergovernmental forum for negotiating the global response to climate change.
This and the other 16 SDGs extend and expand the 8 Millenium Development Goals (MDGs) that established a global partnership to reduce extreme poverty between 2000 and 2015.
UN UN General Assembly resolution adopted 25 September 2015 [.pdf]
Source graphic Stockholm Reslience Centre
Planetary boundaries research includes greenhouse gas concentrations and their temperature effects. And, it adds 8 other boundaries to offer a more holistic set of suggested environmental markers for humankind to develop within or risk disasterous consequences and irriversible environmental change that may be detrimental for human development.
This is a research framework, not a policy framework that has been adopted by UN member states. The use of this framework implies an objective that human activities minimize pressure on the earth system in order for human development to be sustainable at the planetary level for the long term.
Researchers acknowledge that signficant uncertainty exists for quantifying boundaries and identifying the implact of one transgressed boundary on other earth system boundaries. The research appraoch is cautionary in its methods and offers advance warnings where human pressures put human development at risk.
The framework is introduced as a way of broadening the focus on climate system issues to include the broader context of earth system change.
Scientists created the "planetary boundaries" concept as a research framework to help identify and quantify a safe zone or operating space in which humanity can thrive for generation after generation. Johan Rockström and other leading academics (2009) first proposed nine tightly-interlinked biophysical thresholds that, if crossed, "could see human activities push the earth system beyond the stable environmental state of the Holocene, with consequences that are detrimental or even catastrophic for large parts of the world" (p. 472). Tentatively, they suggested quantified markers for seven of the boundaries as "best first guesses."
For one of the boundaries, climate change, they propose an alternative to the 2°C guardrail approach and propose boundaries consisent with an earlier finding by James Hansen and colleagues (2008). That is, they suggest, atmospheric CO2 concentrations should not exceed 350 parts per million and radiative forcing should not exceed 1 watt per square metre above pre-industrial levels (in 1750). They warn that most climate models do not include long-term feedback processes that can push temperatures far higher than projected (i.e. to 6°C where 3°C was projected). "This," they wrote, "would threaten the eological life-support systems that have developed in the late Quaternary environment ad would severely challenge the viability of contemporary human societies" (Rockström et al., 2009, p. 473).
By proposing nine boundaries, the framework offers a more comprehensive perspective for learning about and responding to global environmental challenges. The 2009 paper acknowledges greenhouse gases other than carbon by proposing 'radiative forcing' as a quantified threshold--a measure affected by all greenhouse gases.
Signficantly, it broadens the perspective to include critical environmental threshold that related directly to the global carbon cycle (atmospheric CO2 and ocean acidification) and those that have less of an overlap. For those latter type of thresholds, examples include nitrogen and phosphorus cycles affected by agriculture, unprecedented rates of extinction, changes in freshwater use, and the accumulation of persistent chemical pollutants.
Researchers highlighted three planetary boundaries--climate change, biodiversity loss and enhanced nitrogen cycles--where the rapid changes "cannot continue without significantly eroding the resilience of major components of earth-system functionning" (p. 473).
In 2015, Will Steffen and many of the original researchers (2015) published an update to the planetary boundaries framework. The update responded to input from relevant scientific communities and general scientific advances. They introduced a two-tier approach that identifies the signficance of particular boundaries. That is, climate change and biosphere integrity were identified as the "two core boundaries...each of which has the potential on its own to drive the earth system into a new state should they be substantially and persistently transgressed" (p. 1).
The researchers responded to accumulated evidence that has narrowed the "zone of uncertainty" for CO2 as a climate change marker. As a result, they narrowed the range for atmospheric CO2 from 350-550 ppm to 350-450 ppm. They retained the range of uncertainy for radiative forcing of between +1.0 and +1.5 W/m2, noting that radiative forcing was +2.3 W/m2 in 2011 relative to 1750.
Planetary boundaries research responds to a common assumption that "world development within the biophysical limits of a stable earth system has always been a necessity" (p. 7). The researchers claim to take a precautionary approach that takes uncertainty into account and "also allows society time to react to early warning signs that it may be approaching a threshold and consequent abrupt or riskky change" (p. 2). Emphasis is placed on the need to account for inertia of slow earth system processes, for example, in climate change.
SRC Planetary boundaries research [This page has many additional links]
Hansen, J., Kharecha, P., Sato, M., Masson-Delmotte, V., Ackerman, F., Beerling, D. J., . . . Parmesan, C. (2013). Assessing “dangerous climate change”: Required reduction of carbon emissions to protect young people, future generations and nature. PloS one, 8(12), 1-26. [link]
Hansen, J., Sato, M., Kharecha, P., Beerling, D., Berner, R., Masson-Delmotte, V., . . . Zachos, J. C. (2008). Target atmospheric CO2: Where should humanity aim? arXiv preprint arXiv:0804.1126. [link]
IPCC. Climate Change 2007. Working Group III: Mitigation of Climate Change. Section 1.2.2: What is dangerous interference with the climate system? Retrieved October 5, 2015, from https://www.ipcc.ch/publications_and_data/ar4/wg3/en/ch1s1-2-2.html [link]
Rockström, J., Steffen, W., Noone, K., Persson, A., Chapin, F. S., Lambin, E. F., . . . Foley, J. A. (2009). A safe operating space for humanity. Nature, 461(7263), 472-475. [link via NASA Goddard]
Steffen, W., Richardson, K., Rockström, J., Cornell, S. E., Fetzer, I., Bennett, E. M., . . . Sörlin, S. (2015). Planetary boundaries: Guiding human development on a changing planet. Science. doi:10.1126/science.1259855 [purchase]