Scientists say that the climate crisis is real, grave and driven by human activity. However, scientific consensus doesn’t solve four challenging political equations.

First, catastrophism doesn’t help. Extreme rhetoric makes domestic and international agreement, through compromise and accommodation among different political parties and governments, even more difficult, especially when it’s not clearly or consistently backed by the evidence. Seven scientists write: ‘If damaging tipping cascades can occur and a global tipping point cannot be ruled out, then this is an existential threat to civilization’ (emphases added). This is a multicontingent, speculative assertion. If the science is robust enough, the conclusions should be stated firmly and unequivocally.

Historically, climatic warming and cooling go through extended cycles with no apparent pattern to their intensity, severity and timing. The relative potencies of the different drivers of climate variability—CO₂ emissions, solar radiation, ocean circulation patterns, volcanic eruptions, planetary orbital oscillations—are not known.

Natural disasters caused substantially higher casualties in the first six decades of the 20th century compared with the following 60 years, but more extreme weather in the second 60 years accompanied rising emissions. The deadliest disasters have been earthquakes and tsunamis. Along with growing population, encroachments on habitats, land and water use practices, pesticides and overfishing have had major adverse consequences.

Many doomsday warnings failed to eventuate. In 1982, UN Environment Programme Executive Director Mostafa Tolba warned of an irreversible catastrophe by 2000. While another UNEP official in 1989 said 2000 was the cut-off date, in 2007 IPCC Chair Rajendra Pachauri warned that 2012 was the deadline for necessary action. In 2009, NASA scientist Jim Hansen gave President Barack Obama only four years to save the world from climate catastrophe.

Alarmist predictions become stuck in the ‘cry wolf’ trap. The UNEP’s Emissions gap report 2019 says that even if all current promises are kept the world will warm by double the 1.5°C ceiling by 2100. However, 136 of the 184 Paris Agreement’s climate commitments will not meet the 1.5°C or even the 2°C goal. Why bother, then?

Second, domestic politics militate against robust action. The sacrifices demanded are immediate, real and substantial. The gains are projected, future, generalised and diffuse. The logic of individual costs and benefits clashes with the logic of collective action. Protests against rising fuel and transport prices in France in 2018 and in Chile in 2019 are a harbinger of future riots elsewhere.

The equation just doesn’t compute. Poor countries don’t want to stay poor, and sizeable numbers of working- and middle-class people in rich countries will revolt if pushed into poverty. For Africans and Asians, climbing out of poverty is critical and urgent. Drastic climate action can wait until after they’ve risen on the income ladder. Equally, Western leaders will face political extinction if they commit to drastic drops in living standards to enable income convergence with poor countries and help them to decarbonise.

Third, the international political problems are formidable. Most of the global stock of CO₂ emissions came from the industrialisation of the advanced economies, powered by fossil fuels. There’s also a vast asymmetry between aggregate and per capita emissions. China’s annual per capita emissions (7.9 tonnes) are half Australia’s (16.8 tonnes), but the two countries account for 29.3% and 1.1% of world emissions, respectively. Unable to resist the temptation of finger-pointing for domestic political gain rather than problem-solving for global benefit, Energy Minister Angus Taylor argues that Australia’s emissions have fallen by 12.9% since 2005 but China’s and India’s have increased by 67% and 77%, respectively. They would point fingers at our per capita emissions.

China’s planned expansion of coal-fired power by 147.7 gigawatts matches the EU’s entire output. China is also financing more than one-quarter of coal development in other countries. Why should the rest cut coal production? India’s annual energy consumption is 1.0 megawatt hour per person, compared with the world average of 3.2 MWh and Australia’s 10.5 MWh. India is investing heavily in renewables as well as nuclear, but coal is essential for energy grid reliability and stability and, despite falling from the current 72% of electricity production, will still account for 50% by 2030. India’s coal-fired power generation is forecast to grow by 4.6% per year over the next five years—the highest growth of any country.

Worth A$67 billion, coal was Australia’s top commodity export in 2018. It makes no economic or environmental sense, and therefore no political sense, to stop exports to India. If India is committed to increasing its coal-sourced power supply anyway, why should Australia forgo export revenue and shed mining jobs? If Australian coal is cleaner than the alternatives (as seems likely), the exports should be net global emissions-neutral.

Fourth, because climate policy is not cost-free, governments will be tempted to cheat. To prevent a cascade of breakouts from agreed targets, we need mechanisms to detect cheating and enforce compliance. That’s inconceivable in principle, as it cuts to the heart of national sovereignty, and unfeasible in practice. In the top tier by both net (13.8% of world share) and per capita (16.4 tonnes) measures, the US has disengaged from international efforts to cut emissions. Absent an effective global regime to check national industrial, energy and development policies, defection from the collective regime becomes a rational response for individual countries, even though it amounts to collective suicide globally.

Aggressive action as a policy priority can come only from the world’s political leaders. Climate policy cannot dictate all public policies. While government decisions should be informed by the scientific consensus that the world is in the gloaming zone of climate change, the key calculations will be the balance of political risks and rewards of policy options.

All governments work to balance competing priorities of economic growth, job security, cost-of-living increases, energy security, industrial competitiveness, conservation, and environmental protection. The way to search for feasible and realistic political courses of action is not to repeat the scientific facts with rising stridency, but to find a path forward through the political dynamics at play both within and among countries. What is the decarbonisation strategy that is feasible, most affordable and least disruptive?