Special Report 1.5

Special Report 1.5 (formally Global Warming of 1.5°C, often abbreviated SR15) is a landmark report published by the Intergovernmental Panel on Climate Change (IPCC) in October 2018. It was commissioned at the request of the United Nations Framework Convention on Climate Change (UNFCCC) in 2015, when Parties adopting the Paris Agreement invited the IPCC to assess the feasibility and consequences of limiting global average temperature rise to 1.5°C above pre-industrial levels, alongside the broader 2°C goal.

The report was prepared by 91 authors from 40 countries and synthesised more than 6,000 scientific references. It was formally approved by governments at the IPCC's 48th Session in Incheon, South Korea, in October 2018.

Key findings include:

• Human activities had already caused approximately 1.0°C of warming above pre-industrial levels as of 2017, with current trends pointing toward 1.5°C between 2030 and 2052 if emissions continued at their then-current rate.
• Limiting warming to 1.5°C requires global net anthropogenic CO₂ emissions to fall by about 45% from 2010 levels by 2030 and reach net zero around 2050.
• The difference between 1.5°C and 2°C of warming is substantial for coral reefs (70–90% loss at 1.5°C versus more than 99% at 2°C), Arctic sea ice, sea-level rise, species loss, and risks to food security and human health.
• All assessed 1.5°C pathways rely on some degree of carbon dioxide removal (CDR), including afforestation and bioenergy with carbon capture and storage (BECCS).

SR15 reshaped climate diplomacy by giving political weight to the 1.5°C target, which had previously been seen as aspirational. It directly informed campaigns such as Fridays for Future and underpinned the net-zero by 2050 commitments later adopted by the EU, UK, Japan, and others. The report was followed by SR Ocean and Cryosphere and SR Climate Change and Land in 2019, and fed into the AR6 cycle completed in 2023.