Business on the Edge 2024

In the ocean, the Atlantic’s dominant heat- transferring current, known as the Atlantic Meridional Overturning Circulation (AMOC), has slowed by 15% since 1950 and is in its weakest state for more than a millennium.32 It is showing signs of destabilization on a trajectory towards collapse, partly due to the weakening of the Labrador & Irminger Seas convection current, itself part of the wider North Atlantic Subpolar Gyre and a driver of the bigger AMOC. This vast AMOC current can be likened to an air conditioning system for the planet. It has collapsed in the past. If it were to collapse again, a cold spot in the North Atlantic would emerge while the remainder of the Atlantic Ocean heated. One effect would include shifting the rain belt back to the equator. Tropical forests reliant on this rain would experience unprecedented droughts. As many tropical forests have not evolved the capacity to deal with systemic droughts and their consequential fires, forest systems like the Amazon would be at risk. For more information on risks to Atlantic Ocean circulation, the chain of reactions its failure would unlock geographically, and the global consequences of their decline and tipping, refer to Figure 10. At 1.5°C of global heating, 99% of the world’s coral reefs will experience heatwaves that are too frequent for them to recover from.33 Coral reefs offer an effective barrier to extreme weather from coastal storm surges – so the loss of these ecosystems propels higher costs from extreme weather for many seaboard towns and cities. As a quarter of all marine life are dependent on coral reefs at some point in their life cycle, their loss also affects the composition of ocean ecosystems and coastal food security. Coral reef die-off impacts the livelihoods and food security of half a billion people dependent on the ocean for readily accessible protein.34 For more information on risks to coral reefs, the chain of reactions their destruction unlocks geographically and the global consequences of their decline and tipping, refer to Figure 11. Permafrost could be considered the climate crisis wildcard. By definition, permafrost is ground that remains completely frozen (0°C or less) for at least two years in a row. Permafrost accounts for nearly half of all organic carbon stored within the planet’s soil.35 Northern permafrost soils contain approximately twice as much organic carbon as is currently contained in the atmosphere today.36 With heating in the Arctic, these landscapes are thawing – releasing carbon dioxide and methane into the atmosphere. Permafrost emissions could be anywhere from 30-150 billion tonnes of carbon by 2100 – with upper estimates on a par with cumulative emissions from the US economy at its current rate.37 These “natural” emissions speed up global warming. For more information on risks to permafrost, the chain of reactions its thawing unlocks geographically and the global consequences of its decline and tipping, refer to Figure 12. The figures in this chapter offer briefs for business on the dynamics at play in five critical landscapes: land ice, sea ice, ocean circulation, coral reefs and permafrost. The briefs include: definitions, Earth system tipping points, the way warming leads to climate hazards, select implications, future projections, shocking scientific facts and socio- economic consequences. Inevitably, these briefs simplify the complex nature of Earth systems and the interdependencies between them to explain the primary drivers of relevant tipping points to non-technical readers. They do not aim to be exhaustive. However they do give corporate decision-makers a sense of the scale of emerging and cascading risks involved, as well as primary considerations to inform credible and appropriate responses, in light of those risks. At 1.5°C of global heating 99% of the world’s coral reefs will experience heatwaves that are too frequent for them to recover from, impacting the food security of half a billion people. Business on the Edge: Building Industry Resilience to Climate Hazards 18