In the economy as in ecosystems, one tipping point can lead on to another. Creating cascades of change throughout the global economy is perhaps the only imaginable way we could make the transition to zero emissions at the pace required. This should be the focus of climate change diplomacy throughout this decade. If enough of the world joins in, we might just have a chance.

Important parts of the Earth’s climate and environment can change in ways that are self-reinforcing, sudden, and irreversible. The risks of such changes are under-researched, under-reported in what is communicated by scientists to governments, and underestimated. In the most authoritative science assessments, the most important policy question of all – whether the climate will be stable at low degrees of warming – is hardly even raised.

At COP26, countries representing 70 per cent of the global economy agreed to work together to cross the tipping points where clean technologies outcompete the fossils in each greenhouse-gas-emitting sector of the global economy. This could mark the start of a new era for climate change diplomacy. Success will need support from all sides.

Change in the economy, just as in the climate, can be self-reinforcing, sudden, and irreversible. The world’s fastest transitions to renewable energy and electric vehicles are happening in countries where economic tipping points have been crossed in these sectors. By deliberately targeting these thresholds, we can achieve large-scale change much more quickly than we might expect. To find these opportunities, we need to move away from traditional cost–benefit analysis and adopt a very different approach to decision-making.

New information and evidence challenge equilibrium models. Fluctuations among livestock in African rangelands and northern fur seals in the Pacific Ocean do not conform to models of competition for resources maintaining populations in equilibrium. Rather than the self-interested competition for resources predicted by the tragedy of the commons, many societies regulate resource use through cooperative arrangements. Evidence from several disciplines undermines the concept of a stable climax association that perpetuates itself indefinitely. Some so-called climax communities depend on disturbances, including natural or anthropogenic burning. Some ecosystems have multiple stable states, and some reach irreversible tipping points, which are becoming more likely because of climate change. Viewing nature as in flux rather than in balance addresses these issues, while the current scale of environmental change infuses a sense of urgency into these discussions.

To tilt the scales in favour of a faster energy transition, significant efforts to decarbonise the economy are required. This means flipping the political and economic systems that are failing to deliver deep decarbonisation and replacing them with ones built on compassion and justice. Through a cascade of regime transitions in the energy sector, mass mobilisation, and support politics, these reforms are achievable.

Civilisational collapse could occur. The cascading risks attached to climate change could happen within decades or half a century, so it is no longer the next generation that will carry the burdens of the climate emergency. Before the dominoes collapse, we must take climate risks seriously and act accordingly. If we act now, climate risks can be minimised, if not avoided.

We assault the living world from every angle, and all at the same time. As we remember this onslaught, we grieve. Reminiscing is a powerful act. In grieving, we consider the state of our natural environment and take the necessary actions to rectify our abuse of the living planet.

This chapter provides an introduction to behavioural health economics. Far from attempting to replace what we know about health economics as a discipline, behavioural health economics aims at complementing its foundations by relaxing some of its core assumptions. This implies taking a more ‘realistic depiction’ of individual motivation even though it makes it more complex work beyond simple mathematical formulation. By incorporating what are otherwise anomalies of rational decision-making (defined as purposeful decision-making), health economics can go the extra mile with this extended toolkit which we define as behavioural health economics. Our agent is constrained by the social norms of its place and suffers from status quo bias and endowment effects that introduce bias into making decision and evaluations. ‘Real individuals’ care about others and have social preferences with regard to other people’s well-being, and often suffer from self-control problems, where impulsivity and emotion translate into suffering from a specific form of short sightedness otherwise known as ‘present bias’). These problems are arguably more prominent in the health domain. Market price is not the only relevant variable guiding behaviour in health and health care, where insurance is the most common form of payment, and tangible monetary incentives are often not made salient to influence behaviour.

At COP26, countries representing 70% of the global economy agreed to work together to cross the tipping points where clean technologies outcompete the fossils in each greenhouse gas emitting sector of the global economy. This could mark the start of a new era for climate change diplomacy. Success will need support from all sides.

In the economy as in ecosystems, one tipping point can lead on to another. Creating cascades of change throughout the global economy is perhaps the only imaginable way we could make the transition to zero emissions at the pace required. This should be the focus of climate change diplomacy throughout this decade. If enough of the world joins in, we might just have a chance.

Change in the economy, just as in the climate, can be self-reinforcing, sudden, and irreversible. The world’s fastest transitions to renewable energy and electric vehicles are happening in countries where economic tipping points have been crossed in these sectors. By deliberately targeting these thresholds, we can achieve large-scale change much more quickly than we might expect. To find these opportunities, we need to move away from traditional cost–benefit analysis and adopt a very different approach to decision-making.

Important parts of the Earth’s climate and environment can change in ways that are self-reinforcing, sudden, and irreversible. The risks of such changes are under-researched, under-reported in what is communicated by scientists to governments, and underestimated. In the most authoritative science assessments, the most important policy question of all – whether the climate will be stable at low degrees of warming – is hardly even raised.

Chapter 5 considers the climate crisis, the failure of recent measures, and what must be done by the world community and by individuals.

Chapter 3 lays out in more detail the grave current impacts of global heating, including such extreme weather events as heat waves, droughts, floods, and hurricanes; the alarming projected scenarios if substantial cuts in emissions do not begin soon; and how the methods and assumptions used by many economists have contributed to the failure to cut emissions.

This is our climate change status check, and the first three things to understand are that climate change is real, anthropogenic (i.e., caused by humans), and dangerous. To drive home those points, this chapter relies heavily on the science of the landmark IPCC climate assessments and particularly the most recent AR5 report. We drill down on a key figure from the AR5 to clarify the observed data since 1850 in respect of global average surface temperatures, sea level rise, atmospheric concentrations of several greenhouse gases, and annual CO2 emissions. With a second figure we examine the sources of climate forcing since 1950 and clarify the degree to which they are caused by humanity or by nature. We then divert to key facets that we don’t yet fully understand about climate change, including tipping points, “climate sensitivity” and the likely emissions pathway that humanity will choose over the remainder of the century. We conclude with the observation that irrespective of how these mysteries play out, substantial climate change is in our future. It’s coming.

The concept of Occam’s Razor, also known as the principle of parsimony, is a motivating force in science. Galileo’s experiment of dropping objects of different weights from atop the Leaning Tower of Pisa to show that they fall at the same rate is an illustration of this principle. But the application of Occam’s Razor to climate modeling is less straightforward. Simple models of the kind used by Manabe provide qualitative insights, but they are not well-suited for quantitative predictions. To understand this, we can make an analogy between the hierarchy of climate models and the hierarchy of biological models, from fruit fly to mouse. Simple models are used to explore “climate tipping points,” where amplifying feedbacks lead to abrupt climate change, but they may not consider all the stabilizing feedbacks. It is therefore important to use a hierarchy of models, with varying degrees of complexity, to study climate phenomena.