A group including a young Sami reindeer herder, a member of the Indigenous Yupiaq tribe, and Greta Thunberg are filing a complaint to the UN.
Guterres wanted world leaders to tackle subsidies for fossil fuels, implement taxes on carbon, and end new coal power beyond 2020. None of this happened.
Nations are signed up to limit global heating to well below 2°C, and to aim for 1.5°C. Limiting warming to the latter matters - the future of humanity and the living world is at stake.
As the UN's Climate Action Summit approaches, governments need to start doing more than setting targets. Here's how they can make a start.