Findings from the latest IPCC Special Reports

by Amy Wilson

Alongside Assessment Reports (ARs), the IPCC has published 14 Special Reports (SRs) since 1990 [1]. Three SRs were published as part of Sixth Assessment Cycle (roughly 2015-2022): Global Warming of 1.5 ºC (2019), Special Report on Climate Change and Land (2019), and Special Report on the Ocean and Cryosphere in a Changing Climate (2019) [2, 3, 4]. As part of the Seventh Assessment Cycle, a Special Report on climate change and cities will be published [5].

1) IPCC Special Report: Global Warming of 1.5 °C 

This SR consisted of five chapters, which looked at the impacts of different climate pathways, the carbon budget (the CO₂ emissions permitted over a defined period of time, and if exceeded the global surface temperature will rise),  the importance of limiting warming to 1.5 °C, the dangers of going above 1.5 °C, adaptation and mitigation, and the interactions of both mitigation and adaptation with the other Sustainable Development Goals [6]. 

Key headlines from the SR [7, 8]:

• It is important to limit further global warming between 2018 and 2100. Limiting warming to only 1.5 °C by 2100 is projected to lead to a sea level rise of 0.1 m less than that of a 2 °C warming. This lower level of warming will also reduce increases in ocean temperature. This would reduce the risks to marine biodiversity, fisheries, ecosystems and provide coastal regions longer to adapt [9].
• Climate-related risks to health, livelihoods, food security, water supply, human security, and economic growth are projected to increase with global warming of 1.5°C and increase further with 2°C.
• To meet the 1.5 °C target by 2100, global man-made CO₂ emissions need to decline by about 45% from 2010 by 2030 and then meet net-zero by 2050. To limit global warming to below 2 °C climate pathways suggest CO₂ emissions need to reduce about 25% by 2030, and then become net-zero by 2070. 
• To achieve this ‘deep emissions reductions’ and ‘rapid, far-reaching and unprecedented changes in all aspects of society’ are needed. The report states that carbon dioxide removal (CDR) will need to be used to limit global warming to 1.5°C too [10]. We can limit the reliance on these technologies if we start to take rapid action on reducing emissions by 2030. 
• Meeting these goals should be done in conjunction with poverty eradication strategies and efforts to reduce inequalities. The SR emphasises the involvement of national and sub-national authorities, civil society, the private sector, indigenous people and local community involvement with the implementation of ambitious actions. 

We are currently on track for 2.7-3.1 °C of warming [11]. 

2) IPCC Special Reports: on Climate Change and Land

For the first time the IPCC looked at the whole land-climate system [4]. Aspects such as land-use, impacts of climate change on land, food security and land degradation and desertification were considered.

Key headlines from the SR [4]:

• Agriculture, forestry and other types of land use account for 23% of GHG emissions, but at the same time natural land absorbs CO₂. 
• Land must remain productive (land, vegetation and agricultural) to maintain food security as the population increases, while the negative impacts of climate change on land will continue to rise if the global surface temperature continues to increase. We also need to ensure we reduce food loss and waste to reduce GHG and improve food security. 
• We also need sustainable land management to reduce land degradation and protect communities from the impacts of soil erosion and landslides. 

3) Special Report on the Ocean and Cryosphere in a Changing Climate

Key headlines from the SR [3, 12]: 

• Over the last few decades, global warming has led to a reduction in ice mass, glaciers, snow cover and Arctic sea ice. It is also certain that the ocean has taken more than 90% of the excess heat in the climate system. Global mean sea level is also rising, with acceleration in recent decades due to ice loss. These consequences are expected to continue, as the global surface temperature continues to increase. 
• Climate related impacts will continue to cause increased extreme weather events, coastal hazards, and loss of marine species and ecosystems. 
• There are many ecological, financial, institutional and governance constraints for ocean and cryosphere-related management and adaptation approaches. 
• The report calls for urgent and ambitious emission reductions coupled with coordinated sustained and increasingly ambitious adaptation actions.

References

[1] IPCC. Available at https://www.ipcc.ch/reports/ (accessed 01/03/2021)
[2] IPCC, 2018: Global warming of 1.5°C. An IPCC Special Report on the impacts of global warming of 1.5°C above pre-industrial levels and related global greenhouse gas emission pathways, in the context of strengthening the global response to the threat of climate change, sustainable development, and efforts to eradicate poverty [V. Masson-Delmotte, P. Zhai, H. O. Pörtner, D. Roberts, J. Skea, P.R. Shukla, A. Pirani, W. Moufouma-Okia, C. Péan, R. Pidcock, S. Connors, J. B. R. Matthews, Y. Chen, X. Zhou, M. I. Gomis, E. Lonnoy, T. Maycock, M. Tignor, T. Waterfield (eds.)]. In Press. Available at: https://www.ipcc.ch/sr15/
[3] IPCC, 2019: IPCC Special Report on the Ocean and Cryosphere in a Changing Climate [H.-O. Pörtner, D.C. Roberts, V. Masson-Delmotte, P. Zhai, M. Tignor, E. Poloczanska, K. Mintenbeck, A. Alegría, M. Nicolai, A. Okem, J. Petzold, B. Rama, N.M. Weyer (eds.)]. In press. Available at: https://www.ipcc.ch/srocc/
[4] IPCC, 2019: Climate Change and Land: an IPCC special report on climate change, desertification, land degradation, sustainable land management, food security, and greenhouse gas fluxes in terrestrial ecosystems [P.R. Shukla, J. Skea, E. Calvo Buendia, V. Masson-Delmotte, H.-O. Pörtner, D. C. Roberts, P. Zhai, R. Slade, S. Connors, R. van Diemen, M. Ferrat, E. Haughey, S. Luz, S. Neogi, M. Pathak, J. Petzold, J. Portugal Pereira, P. Vyas, E. Huntley, K. Kissick, M. Belkacemi, J. Malley, (eds.)]. In press. Available at: https://www.ipcc.ch/srccl/
[5] IPCC, Future Work. Available at https://www.ipcc.ch/about/future-work/#:~:text=The%20Special%20Report%20on%20Climate,Changing%20Climate%20in%20September%202019.&text=The%20IPCC%20also%20decided%2C%20at,cities%20in%20the%20AR7%20cycle (accessed 01/03/2021)
[6] United Nations: https://sdgs.un.org/goals (accessed 01/03/21)
[7] IPCC, 2018: Summary for Policymakers. In: Global Warming of 1.5°C. An IPCC Special Report on the impacts of global warming of 1.5°C above pre-industrial levels and related global greenhouse gas emission pathways, in the context of strengthening the global response to the threat of climate change, sustainable development, and efforts to eradicate poverty [Masson-Delmotte, V., P. Zhai, H.-O. Pörtner, D. Roberts, J. Skea, P.R. Shukla, A. Pirani, W. Moufouma-Okia, C. Péan, R. Pidcock, S. Connors, J.B.R. Matthews, Y. Chen, X. Zhou, M.I. Gomis, E. Lonnoy, T. Maycock, M. Tignor, and T. Waterfield (eds.)]. World Meteorological Organization, Geneva, Switzerland, 32 pp.
[8] K. Levin, 8 Things You Need to Know About the IPCC 1.5?C Report, World Resources Institute, (2018). Available at https://www.wri.org/blog/2018/10/8-things-you-need-know-about-ipcc-15-c-report (accessed 04/03/2021)
[9] Carbon Brief (2018). Available at https://interactive.carbonbrief.org/impacts-climate-change-one-point-five-degrees-two-degrees/?utm_source=web&utm_campaign=Redirect, (accessed 04/03/2021)
[10] The Institute for Carbon Removal Law and Policy, Carbon Removal Fact Sheet, (2018): https://www.american.edu/sis/centers/carbon-removal/upload/icrlp_fact_sheet_what-is-carbon-removal_181009.pdf (accessed 04/03/2021)
[11] Climate Action Tracker (2020): https://climateactiontracker.org/global/temperatures/ (accessed 04/03/2021)
[12] IPCC (2019). Available at https://www.ipcc.ch/site/assets/uploads/sites/3/2019/09/SROCC_SPM_HeadlineStatements.pdf, (accessed 04/03/2021)

Credits for featured image: IPCC.