A Decade of the Paris Agreement: Unequal Heat Burdens and Urban Resilience

The Paris Agreement marked a historic step toward a safer and more equitable world, establishing a shared legal and political framework for addressing climate change. Yet, a decade on, current nationally determined contributions (NDCs) and pledges— even if fully implemented—are projected to lead to around 2.6°C of global warming above pre-industrial levels, leaving the planet dangerously hot.Since 2015, heat early warning systems and action plans have increased across the globe, demonstrating growing recognition of extreme heat as a major climate risk. However, progress remains uneven and slow, particularly due to limited financing for heat adaptation at the local level, mainly in rapidly urbanizing cities of the Global South. The costs of inaction are escalating faster than the pace of adaptation: health systems are being overwhelmed, productivity and labour capacity are declining, infrastructure is under stress, and the world’s most vulnerable populations risk being left unprepared for intensifying heat extremes..Here, we show how six recent, highly impactful extreme heat events across the globe have changed in both likelihood and intensity under historical warming levels (since the signing of the Paris Agreement; ~1.0°C and 1.3°C) and under future warming conditions (2.6°C and 4°C), alongside the distribution of impacts and progress in heat action plans.