In December 2020 the IUCN World Heritage Outlook 3 found that climate change is now the biggest threat to natural World Heritage globally. This report, IUCN World Heritage Outlook 3, builds on three cycles of Conservation Outlook Assessments undertaken since 2014. It presents the main results for 2020, but also some longer-term trends based on a comparison of three data sets now available. As such, it can serve as an indicator of the effectiveness of protected and conserved areas at a time when the international community seeks to measure progress towards global biodiversity targets and defines the Post-2020 Global Biodiversity Framework.

The IUCN World Heritage Outlook includes two equally-impor tant components: a website
( providing detailed assessments for each site, and a regular report – which we present here – summarising global and regional results.