A new report finds climate change responsible for the same number of deaths as an Indian Ocean tsunami every single year. It is already responsible for 300,000 deaths a year and by 2030 this number could climb to as many as half a million.

The report is written by former UN Secretary General Kofi Annan’s organisation, the Global Humanitarian Forum, and is the first comprehensive study of the human impact of global warming.

Climate change is threatening lives and livelihoods through increased frequency and intensity of hazardous weather, water shortages, changes in agricultural patterns, and reduced sanitation.