Business on the Edge 2024

Shocking scientific fact Approximately one quarter of all marine species depend on coral reefs in some way, making these ecosystems cornerstones of marine biodiversity. What is it? Coral reefs are underwater ecosystems, which serve as natural barriers against storm surges and extreme wave events. Reefs are threatened by multiple stressors at a range of scales. Local human impacts on reefs include overfishing and destructive fishing, nutrient pollution and urban runoff, and coastal development. On a global scale, climate change threatens coral reefs via marine heatwaves (which cause coral bleaching), tropical storms (which damage coral structure) and ocean acidification (which reduces coral growth). Ocean warming has already triggered multiple global coral bleaching events and it is estimated that 50% of coral cover has already been lost. What are the implications? Loss of coral reef 3D structure could lead to increased coastal erosion and damage from tropical storms, particularly as sea levels rise. The loss of reef-building corals could lead to the collapse of marine ecosystems, significantly impacting food security.Temperature scenario Warm water coral reef die-offScientific confidenceRelated Earth system tipping points Where does it occur?1.0 – 1.5ºC High Warm water coral reef die-offWarm water coral reef die-offWarm water coral reef die-off What could happen? Severe coral reef loss –At 1.5°C of warming 99% of the world’s reefs will experience heatwaves that are too frequent for them to recover from. –70% – 90% loss of tropical and subtropical coral reefs at 1.5°C. –Near total coral reef loss at 2°C. Flooding risk amplification –Future sea level rise paired with coral reef loss will amplify flooding risks.  –By 2100, land flooded under a 100-year storm event increases by 64% under continued high emissions with no reef loss. –In the same scenario with a 1m loss in reefs, land flooded increases by 116%.Coral reefs Related climate hazards Coastal flooding Socio-economic consequences 1 One billion people globally live within 100km of a coral reef and depend on coral reefs for their food and livelihoods. This includes one quarter of small-scale fishers globally. 2 Shorelines would be vulnerable to erosion, while rising sea levels would push coast-dwelling communities out of their homes. 3 From the Great Barrier Reef to the Caribbean Sea, coral reefs attract tourists to over 100 countries and territories worldwide. Coral reef tourism is estimated to generate $36 billion in economic revenue per year, from both on-reef (e.g. diving) and reef-adjacent activities (e.g. hotel stays). Each hectare of coral reef habitat also provides an average of $350,000 in ecosystem services per year. 4 By researching corals’ natural chemical defences, scientists are able to develop medicines to treat all sorts of human diseases, from cancer and arthritis to Alzheimers and heart disease.Network diagram Increased GHGsGlobal warmingElevated sea temperaturesLoss of underwater species Spread of coral diseasesCoral bleaching  Coral reef die-off Loss of coastal protectionMore powerful storm surges and wavesBreaking or displacing coral colonies Ocean acidificationHindering coral calcification and growthFIGURE 11 | LANDSCAPE BRIEF Business on the Edge: Building Industry Resilience to Climate Hazards 22