At the most conservative estimate, climate change is already killing hundreds of thousands of people every year, but the true number may be in the millions. As the world heats up, the number of people dying from climate-related causes such as heatstroke, flooding and malnutrition caused by failing crops will increase. The Intergovernmental Panel on Climate Change has modelled various scenarios for how warming of 1.5°C and 2°C would affect the world. Limiting warming to 1.5°C would mean that around 420 million fewer people will regularly be exposed to extreme heatwaves. It will also significantly reduce the risk of drought and extreme weather events such as cyclones. Unfortunately, even if we keep warming to 1.5°C, the changing climate is likely to endanger 6% of insects, 8% of plants and 4% of vertebrates. But allowing warming to hit 2°C would make the damage much greater: 18% of insects, 16% of plants and 8% of vertebrates would be endangered. The more species decimated, the greater the likelihood of problems with the food chain for humans.