2.2.6.6 Communities, economies and displacement

Story of one collapse: AMOC 

The following narrative explores one climate tipping event: the collapse of the AMOC. It is set in the not-too-distant future. Although judged unlikely, it is plausible that an AMOC collapse could occur this century (see Section 1). The narrative is based on the best available knowledge on the hazards arising if the AMOC were to collapse and uses expert judgement to explore the consequences for societies, as well as OECD 2021 and OECD 2022. The purpose is to ‘bring alive’ this threat, which might otherwise appear abstract when presented in more academic formats. Exploring scenarios is crucial to properly recognising, assessing and managing risks from tipping points and their effects on societies. 

Social media is awash with frightening rumours. A group of scientists and government officials gather to give a press conference about an important system of ocean currents in the North Atlantic. For years, evidence from sensors has been suggesting that the Atlantic Meridional Ocean Overturning Circulation is changing. The press conference confirms that the AMOC, which transports warm waters northwards from the tropics and is crucial to the functioning of the global climate system, has started to collapse, stalling the northward movement of heat.

The collapse plays out over the following few decades. Across Europe and the wider Atlantic region, average temperatures begin to steadily drop. Initially, this is confused as a welcome reprieve from the relentless rise in temperatures caused by climate change, though seasonal and weather extremes increase. But soon rainfall levels begin to drop, exacerbating water insecurity already made extreme by climate change. Large shifts in the monsoon rains in the tropics mean that some regions experience much less rain, and some too little, deepening what is now a profound global water emergency. 

This interacts with an increasingly dire outlook for farming. The number of places suitable for growing major staple crops are diminishing as a result of how the AMOC collapse has affected the climate. Ultimately, the land across the world suitable for wheat and maize – which are critical to global food supply – falls by nearly a half in each case. Europe is particularly hit, with arable farming largely lost in the British Isles. The pace and scale of these changes outstrips the ability to diversify which crops are grown  and where. Shortages of food and higher prices cascade through connected food systems, driving hunger, malnutrition and social and economic instability globally. 

This is a common problem: changes are happening faster and more severely than systems – whether food, financial, economic or social – are adapted to or able to keep up with. There is general anger and resentment at the failure to foresee such risks, which feeds into a wider sense of betrayal, resentment and fear, with repercussions for cooperation and political stability. 

The impacts of AMOC collapse combine with the ongoing effects of climate change, biodiversity loss and other environmental problems, with catastrophic consequences. The conditions that make for good health and economic development are severely affected across large parts of the world, while the conditions for conflict are growing. Societies struggle to cope with the multitude and pace of problems impacting all facets of life. Some are simply unable to cope. The escalating instability gets in the way of decarbonisation, leading to higher temperatures, more instability and less decarbonisation and this vicious cycle further degrades the prospects for civilization.