n: the magnitude or intensity that must be exceeded for a certain reaction, phenomenon, result, or condition to occur or be manifested.
-Oxford English Dictionary
Crossing a threshold or going over a tipping point fundamentally changes a system from one stable state to another, often irreversibly. Though thresholds and tipping points are not new concepts, novel applications of the idea of “positive tipping cascades'' may offer an important shift in how we, as a global society, can frame research and policy toward solving climate change. Positive tipping cascades push us to transcend incrementalism by pursuing reinforcing positive feedback loops that provide more “bang for the buck” to reduce the greenhouse gases that cause climate change.
Abrupt shifts in dynamical systems have been described by mathematicians and engineers as early as the late 19th century. In more recent decades, ecologists and social scientists have documented linked ecological, physical, and social “regime shifts,” which are defined as large, persistent changes in the structure and function of social-ecological systems, with substantive impacts on the suite of ecosystem services provided by these systems. Examples of regime shifts range from coral bleaching, to sudden lake turbidity, to desertification, to the collapse of ancient societies. More than 100 case studies of such regime shifts have been archived by the Resilience Alliance in a Thresholds Database and Regime Shifts Database, which provide detailed accountings of abrupt shifts that have transformed natural and human systems abruptly from one state to another.
In the early 2000s, climate researchers began to document clear thresholds in the global climate system, projections for abrupt and potentially irreversible shifts under future warming scenarios. Climate tipping points, from collapsing ice sheets and thawing permafrost, to shifting monsoons and forest dieback, warn of impending points of no return. A collective scientific understanding of thresholds has been reflected in reports by the Intergovernmental Panel on Climate Change (IPCC) since at least 2007, with many examples of changes with drastic consequences. Since 2018, the global scientific community has identified 1.5°C through an IPCC Special Report as a threshold of warming beyond which the planet will experience blistering heat waves, extended megadroughts, intense storms, and sea level rise – impacts that are well underway today.
In a social context, the idea of thresholds first gained broad recognition when Canadian author Malcolm Gladwell published his bestselling book in 2006, Tipping Point: How Little Things Can Make a Big Difference. Gladwell writes, “The tipping point is that magic moment when an idea, trend, or social behavior crosses a threshold, tips, and spreads like wildfire...” These tipping point concepts are achingly familiar today, especially in the context of rapid societal changes wrought by the global COVID-19 pandemic.
Positive Tipping Points Transcend Incrementalism
Mounting scientific evidence that catastrophic climate tipping points are an inevitable part of a warming future does little to dispel a gloom and doom narrative for climate change. But a growing body of scientific research is developing a more hopeful counternarrative, one in which linked policy actions promote behavior and market changes, which in turn, help to jumpstart the same kinds of rapid changes that promote the recovery of natural systems and reverse the impacts of global warming. These scenarios outline conditions where thresholds and tipping points accelerate a transition to a climate positive future, one that includes just and equitable access to resources and representation, and deliberate action to regenerate human and social systems, providing additional benefit to people and the planet.
To date, researchers have only documented a few examples of instances where policy interventions have triggered positive tipping points at a national scale. But there is clear untapped potential for future policy interventions that accelerate threshold transitions that reverse global warming. In a recent paper in the journal Climate Policy, policymaker Simon Sharpe, Deputy Director at the UK Government's Cabinet Office COP26 Unit, and Timothy Lenton, Professor of Climate Change and Earth System Science at the University of Exeter, identify several examples of tipping cascades in human societies that could rapidly cut carbon emissions.
Electric vehicles (EVs) offer one powerful case study. According to Sharpe and Lenton’s study, Norway has already passed a national scale tipping point for the sale of electric vehicles (EVs), which is currently more than ten times higher than any other country, thanks to policies that make EVs the same price to buy as conventional cars. A global tipping point toward EVs could occur when they cost the same to manufacture as conventional cars, and a small number of key locations could help drive this change, such as China, the European Union, and state of California, which are collectively responsible for half the world's car sales and have targets to rapidly decarbonize their economies. Acting together, they could shift investment throughout the global industry, increasing EV production and decreasing costs, triggering a global tipping point to EVs. This in turn would make batteries better and cheaper, which would aid decarbonization in the power sector.
Electric vehicles offer just one example. Similar tipping cascades could be envisioned in power systems or in food systems, as the market pressure for plant-based diets grows stronger, for example. Researchers from diverse disciplines, such as ecology, climate science, economics, mathematics, and policy analysis have a unique opportunity to grow a body of evidence on potential positive tipping points, and to work with decision-makers to inform intentional policy.
Toward 2030: A Need for Systems Thinking in Science and Policy
As we approach target climate milestones in 2030 and beyond, there is great global urgency to unleash the power of these “upward scaling tipping points.” To move in this direction, however, will require collective vision and collaborative policymaking, with the power to move markets and promote behavior change. As scientists, economists, and mathematicians identify more instances where the shift in one system can drive change in others, policymakers from different regions in the world and at different levels of government will need mechanisms and incentives to coordinate policy development to rise to the challenge.
Systems thinking for policy is underway, but has not yet become mainstream or widely adopted. In 2020, the Organization for Economic Cooperation and Development (OECD), an intergovernmental economic organization with 38 member countries that works to stimulate economic progress and world trade, published a report on Systemic Thinking for Policy Making. This report asserts that to tackle planetary emergencies linked to the environment, the economy and socio-political systems, we have to understand their systemic properties, such as tipping points, interconnectedness and resilience, and offers tools to approach policies for climate, air, energy, and ecosystems through a systems-thinking lens.
Systems-thinking approaches to both science and policy can bring rapid improvement in reversing the impacts of climate change and as such, real reasons for optimism. And by applying the same thinking that sparks fear of looming dangerous climate thresholds, we can rapidly accelerate a transition to a climate positive future*. To accomplish this goal, will require true boundary spanning between science and decision-making at all levels of government, coupled with policy entrepreneurship and a bridging between sectors and scales that is so far unprecedented, but well within our collective reach.
* Note: GCSE defines a climate positive future as one where planetary warming has not exceeded 1.5 degrees, and GHG emissions are reversed, not only curbed, and replaced by measurably positive impacts (e.g., systems infrastructure to support a clean energy future, increased diversity in skills needed and jobs available).
Biggs, R., G. D. Peterson, and J. C. Rocha. 2018. The Regime Shifts Database: a framework for analyzing regime shifts in social-ecological systems. Ecology and Society 23(3):9.
Gladwell, Malcolm (2006). The Tipping Point: How Little Things Can Make a Big Difference. Little, Brown and Company.
Hynes, W., M. Lees and J.M. Müller (eds.) (2020), Systemic Thinking for Policy Making: The Potential of Systems Analysis for Addressing Global Policy Challenges in the 21st Century, New Approaches to Economic Challenges, OECD Publishing, Paris, https://doi.org/10.1787/879c4f7a-en.
Lenton, Timothy M. 2020. Tipping positive change.Phil. Trans. R. Soc. http://doi.org/10.1098/rstb.2019.0123
Resilience Alliance and Santa Fe Institute. 2004. Thresholds and alternate states in ecological and social-ecological systems. Resilience Alliance. (Online.) URL: http://www.resalliance.org/index.php/thresholds_database.
Sharpe, Simon & Timothy M. Lenton (2021) Upward-scaling tipping cascades to meet climate goals: plausible grounds for hope, Climate Policy, 21:4, 421-433, DOI: 10.1080/14693062.2020.1870097