We must limit global warming to 1.5 °C rather than the previously agreed cap of 2 °C to avoid extreme heat, drought, floods, and poverty, according to a landmark climate report released this morning.

The warning: Governments need to take “rapid, far-reaching, and unprecedented changes in all aspects of society” to avoid the disastrous effects of global warming, the report says. Given current trends the 1.5 °C threshold could be reached as early as 2030. Human-produced carbon dioxide emissions would have to drop by 45% from 2010 levels by 2030, reaching “net zero” by 2050, according to the report.

The report: It was written by 91 authors from 40 countries and approved by the Intergovernmental Panel on Climate Change on Saturday. The conclusions are based on an analysis of more than 6,000 separate climate studies. It will be one of the main items discussed at a global conference in Poland in December, when governments will review the Paris agreement (which the US announced plans to withdraw from in June 2017).

A role for tech? It will be very difficult to meet the ambitious carbon dioxide targets without technological innovations such as solar energy, wind energy, and electricity storage, the report says. On the plus side, these technologies are becoming increasingly viable, it adds. That’s one small ray of hope in an otherwise hair-raising read.