Appendix: Climate risks associated with 1.5°C and 2°C warming
1)The figures below contain summaries by the Committee on Climate Change and the Intergovernmental Panel on Climate Change relating to the risks associated with 1.5°C and 2°C global heating.
Figure 8: The Committee on Climate Change’s summary of climate risks below 2°C and 1.5°C of global heating
Source: Committee on Climate Change, Net Zero: The UK’s contribution to stopping global warming, (2019) p.31
Figure 9: IPCC’s depiction of how the level of global heating affects impacts and/or risks associated with the Reasons for Concern, and selected natural, managed and human systems
Source: IPCC, Global Warming of 1.5°C: Summary for Policymakers, (2018), p.13
2)In the above figure the five integrative Reasons for Concern (RFC) provides a framework for summarising key impacts and risks across sectors and regions, based on IPCC’s assessment of the new literature that has appeared.236 IPCC defines the RFCs as follows:
- RFC1 Unique and threatened systems: Ecological and human systems that have restricted geographic ranges constrained by climate-related conditions and have high endemism or other distinctive properties. Examples include coral reefs, the Arctic and its indigenous people, mountain glaciers and biodiversity hotspots;
- RFC2 Extreme weather events: Risks/impacts to human health, livelihoods, assets and ecosystems from extreme weather events such as heat waves, heavy rain, drought and associated wildfires, and coastal flooding;
- RFC3 Distribution of impacts: Risks/impacts that disproportionately affect particular groups due to uneven distribution of physical climate change hazards, exposure or vulnerability;
- RFC4 Global aggregate impacts: Global monetary damage, global-scale degradation and loss of ecosystems and biodiversity; and
- RFC5 Large-scale singular events: Are relatively large, abrupt and sometimes irreversible changes in systems that are caused by global warming. Examples include disintegration of the Greenland and Antarctic ice sheets.237
3)In relation to the impacts and risks for selected natural, managed and human systems, the IPCC report emphasises that this selection is “illustrative and not intended to be fully comprehensive.”238
236 IPCC, Global Warming of 1.5°C: Summary for Policymakers, (2018), p.13
237 Ibidem.
238 Ibidem.
Published: 10 June 2019