1 Trillion Tonnes
The remaining global carbon budget – the limit of what we can still emit in the future – must be well below 1000 Gt CO2 to have a reasonable chance to hold the 2°C line. Humankind has already emitted around 2000 Gt CO2 since the beginning of industrialization. Respecting the global carbon budget means leaving at least three quarters of all known fossil fuel reserves in the ground. With current emissions trends, the remaining 1000 Gt CO2 would be used up within the next 25 years.