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.

Humanity’s situation with climate change is sometimes compared to that of a frog in a slowly boiling pot of water. Most of our climate science takes the form of prediction: telling the frog that in five minutes’ time he will be a little bit warmer. We need more risk assessment: telling the frog that the worst that could happen is he could boil to death, and that this is becoming increasingly likely over time. This approach can give a much clearer picture of the risks of climate change to human health, food security, and coastal cities.

The year 2021 saw extreme weather events outside the range of what experts had thought possible, signs of a growing acknowledgement among scientists of the need to take risk assessment more seriously, and the launch of a new initiative that might finally tell heads of government what they need to know.

The UK’s desire to prove its international relevance after Brexit, together with the COVID pandemic, produced a unique opportunity: a two-year Presidency of the UN climate talks for the country that has long been the most active in climate change diplomacy. A chance to test a new approach – after thirty years of slow progress, better late than never.

A movement is gathering to overthrow the intellectual incumbents of economics. Started by students, advanced by academics, and funded by philanthropists, until recently it has remained largely unnoticed by governments. Now the world’s largest emerging economies are starting to take an interest. For the sake of avoiding dangerous climate change, the revolution cannot come too soon.

The first twenty years of international negotiation on climate change took an approach that was guaranteed to fail: attempting to solve an immensely complex issue through a single, legally binding agreement. The history of diplomacy in trade and security shows that success requires a different approach: breaking a problem up into manageable parts, and growing agreement gradually, strengthening it as parties’ interests increasingly converge.

Neither scientists, nor economists, nor insurers, nor military planners have assessed the risks of climate change in full. Heads of government are left to guess. A clear understanding of the scale of the risks will not on its own guarantee a proportionate response. But unless we have such an understanding, we can hardly be surprised if our response is inadequate.

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.

Estimates of the economic costs of climate change rely on guesswork in the face of huge uncertainties, and arbitrary judgements about what is important. The models can produce any number their creators want them to; and typically, they trivialise the risks. Despite being described as ‘worse than useless’ by leading academics, economic analysis of this kind has been credited with a Nobel Prize, and it continues to inform government policy.

Most research into the impacts of climate change concentrates on what would happen at low degrees of change. We know a great deal about best-case scenarios. Thanks to wilful ignorance among policymakers, and the cultural preferences of scientists, worst-case scenarios are much less considered. We know the least about what matters most.

People often assume that to give ourselves a fighting chance of avoiding catastrophic climate change, we need either inspired political leadership, or a moral revolution in society. Both would be nice to have, but there are more plausible ways to make faster progress. They involve thinking differently. We need science that gives us risk assessment instead of prediction; economics that understands change instead of assuming stability; and diplomacy that focusses on international collaboration instead of unilateral national action.

The trade that destroys forests is worth a hundred times the money that is spent on protecting them. This will only change if the top producer and consumer countries of forest-risk commodities agree steps to shift global markets towards sustainability. We brought these countries together for the first time, to see if it could be done.

The Paris Agreement on climate change has been widely hailed as a diplomatic triumph, but it commits its signatories only to a process, not to anything of substance. It represents a gamble: that if enough governments say they will act, they will believe each other and have the confidence to move forward – and that businesses and investors will believe them too. Six years later, the gamble appears to be succeeding, but despite this, progress is nowhere near fast enough. Global emissions of greenhouse gases are still going up.

I open the book with the political struggle that took place between parties at COP24, over whether the IPCC Special Report on 1.5°C should be noted or welcomed. This provides the context for exploring the IPCC as a central site in and producer of climate politics. In the chapter, I take the reader back to where this study began, with the question, who has the power to define climate change for collective response and what constitutes this power? The answer the book offers is the practice of writing. The actors, activities and forms of authority framework provides the analytical framework for exploring the asymmetries in power to effect how climate change is written. This approach has developed from interviews, observation and extensive data collection from IPCC documentation. The resulting book takes the reader on a journey into the intricate details of writing an assessment, the social order through which it is written and how climate change is known and acted upon through the process.

This chapter sets out to identify key conceptual resources available for exploring power in the social construction of global environmental degradation for collective response. The chapter begins with the epistemic community model, which illuminates the role that transnational communities of scientists have in identifying issues like climate change and informing political action. This approach has been important for documenting the origins and establishment of the IPCC in 1988. However, empirical accounts informed by discursive and normative frameworks in other issue areas challenge the centrality of scientists in treaty formation. The studies reviewed identify the emergence of environmental issues as the source of new institutions; however, they also highlight how problem diagnosis has to converge with prevailing political and economic orders. Revisiting the IPCC’s emergence through the idiom of co-production at the end of the chapter, reveals how climate change had to be transformed into a global problem to fit with the existing remit of international organisation.