The economic damages of 3°C warming for SIDS and LDCs

The current round of national emission reduction pledges (Nationally Determined Contributions/NDCs) will lead to about 3°C of warming by the end of the century. This tool shows the additional economic damages Small Island Developing States (SIDS) and Least Developed Countries (LDCs) face in a 3°C world compared with 1.5°C, the limit set out in the Paris Agreement.

Current Nationally Determined Contributions (NDCs) set us on track to about 3°C of global warming, which could result in substantially larger reductions in GDP per capita compared to limiting the warming to 1.5 degrees. Based on the methodology of Burke et al. (2018), we estimate projected GDP per capita associated with a current warming trajectory of 3°C, compared to a Paris compatible 1.5°C pathway.

Map: The percentage difference in GDP per capita between the two temperature pathways for mid- and end of century.

Bar plots: Percentage difference between GDP per capita under a 1.5 (3) degrees pathway and GDP under a no climate change scenario for mid-century and end-of-century.

Methods:

  • The relationship between GDP and temperature variability is examined through a probabilistic framework that accounts for uncertainty. The estimates obtained from that historical response functions are used to project future trajectories of GDP growth, by combining them with the Intergovernmental Panel on Climate Change (IPCC) projections of future climate. The impacts on GDP are calculated for the mid-century (2046-2065) and end-of-century (2081 – 2100). We calculated projected changes in GDP per capita under two temperature pathways based on the Representative Concentration Pathways (RCPs) 2.6 and 6.0. Based on the estimates of the Warming Attribution Calculator, in mid-century RCP 2.6 (6.0) results in 1.67°C (1.87°C) higher temperature compared to the preindustrial period, and for end-of-century temperatures reach 1.66°C and 2.92°C higher temperatures for the two RCPs respectively.
  • The bar plots show damages for GDP per capita derived relative to GDP in a counterfactual no-warming scenario, informed by projections from the Shared Socioeconomic Pathways (SSPs).
  • Missing data for some countries was proxied by the estimates for their closest neighbor with similar geographical and socio-economic characteristics.
Acknowledgements: We thank Marshall Burke and co-authors for providing their analysis openly available on https://github.com/wmadavis/BDD2018. This has allowed us to replicate their results to provide the country-level analysis.