Business on the Edge 2024

What is it? The Greenland and Antarctic ice sheets store approximately 99% of the Earth’s land ice and have a profound impact on global climate, sea levels and ecosystems. Ice sheets are in danger of collapsing in response to both atmospheric and oceanic warming, which affect their surface mass balance and ice dynamics. Mountain (extrapolar) glaciers are receding rapidly due to rising temperatures, diminishing snowfall and increased meltwater runoff. The Himalayan glaciers are invaluable sources of freshwater for approximately 800 million people. What are the implications? Loss of land ice results in sea level rise, which leads to coastal floods, coastal erosion and saltwater intrusion into groundwater. Melting of mountain glaciers causes moraine dams to fail, leading to glacial-lake outburst floods (GLOFs). Subsequent glacier retreat reduces river flows and worsens downstream droughts. Increased freshwater from land ice enters the oceans and disrupts global ocean circulation and salinity.Temperature scenario Greenland ice sheet collapse* West Antarctic ice sheet collapse East Antarctic ice sheet collapse Extrapolar glacier retreat Scientific confidenceRelated Earth system tipping points Where does it occur?0.8 – 3.0ºC 1.0 – 3.0ºC >5.0ºC 1.5 – 3.0ºCHigh High Medium Medium Greenland ice sheet loss Extrapolar glacier loss (Alps & Caucasus) Extrapolar glacier loss (Hindu Kush Himalaya) Extrapolar glacier loss (Rockies) Extrapolar glacier loss (Andes) West Antarctic ice sheet lossEast Antarctic ice sheet loss Shocking scientific fact Some of the latest estimates suggest that 630 million people may live on land below projected annual flood levels for the end of the century. The displacement of so many people could lead to a global security crisis, with increased competition for freshwater, land and other resources.What could happen? Accelerated sea level rise IPCC sea level rise projections by 2100: –0.28 – 0.55 metres (RCP2.6** scenario). –0.61 – 1.10 metres (RCP8.5 scenario). –These do not account for the full range of possible ice sheet instabilities, which could add centimetres to metres of sea level rise by 2100 and multi-metre increases towards 2300. * * RCP2.6 is the IPCC’s lowest-emissions/warming scenario; RCP8.5 is the highest-emissions/warming scenario.* See endnote on Greenland ice sheet.38 Socio-economic consequences 1 Sea level rise acts as a threat amplifier for extreme weather events in coastal areas. It could damage coastal infrastructure, compromise port operations, contaminate farmland and groundwater, and lead to increased coastal erosion. Sea level rise is among the most costly and permanent future consequences of climate change. 2 Latest estimates suggest that 630 million people may live on land below projected annual flood levels for the end of the century. This could lead to displacement, loss of property and other socio- economic challenges. 3 Loss of glaciers will lead to greater water stress during droughts, with implications for downstream communities’ municipal, industrial and agricultural sectors that rely on those water sources. 4 Glacial-lake outburst floods destroy settlements and infrastructure in mountain regions, including hydroelectric power installations and transport links.Increased GHGsGlobal warmingLand ice lossIce sheet destabilizationIncreased influx of freshwater from melting ice Mountain glaciers meltingSea level riseOcean circulation disruption Coastal erosionChanges in rainfall patternsNetwork diagramIncreased water levels and fluvial floods –The majority of Himalayan glaciers are losing mass at an accelerating rate. Peak water is likely to be reached in the Ganges, Indus, Tarim and Brahmaputra rivers by 2050. –The frequency and magnitude of glacial lake outburst floods (GLOFs) are expected to increase in the future due to climate change. Breaches of ice or moraine dams; flooding of glacier-fed rivers Progressive reduction in water volumes of glacier-fed riversLand ice Related climate hazards Fluvial flooding Water stressCoastal floodingFIGURE 8 | LANDSCAPE BRIEF Business on the Edge: Building Industry Resilience to Climate Hazards 19