Analysis
The **IPCC’s 2018 Special Report on 1.5°C** confirms that warming beyond 1.5°C would severely exacerbate risks for small island states and coastal nations, including catastrophic sea-level rise, coral reef die-offs, and extreme weather (e.g., cyclones in Barbados, flooding in Mozambique). However, 'death sentence' is hyperbolic: while 2°C would cause **irreversible damage** (e.g., loss of 99%+ coral reefs, displacement from sea-level rise), adaptation measures (e.g., seawalls, managed retreat) could mitigate *some* impacts. The claim conflates **probabilistic risks** (e.g., increased mortality from heat/ storms) with **certain annihilation**, which lacks empirical precision.
Background
The **1.5°C threshold** was enshrined in the 2015 Paris Agreement after lobbying by vulnerable nations, including those Mottley named (e.g., Maldives, where 80% of land is <1m above sea level). These countries contribute **<1% of global emissions** but face disproportionate climate impacts. The **IPCC AR6 (2021–23)** reaffirmed that 2°C warming would double the population exposed to **multi-sector climate risks** compared to 1.5°C.
Verdict summary
Mia Mottley’s claim about the existential threat of **1.5°C vs. 2°C warming** to vulnerable nations is **largely supported by climate science**, though the framing as an absolute 'death sentence' oversimplifies complex, region-specific impacts.