"Carbon budget" is one of the most frequently mentioned terms in the COP26 talks in Glasgow. What is it? As explained by Sven Teske, a researcher at the University of Technology Sydney (Sven Teske), "a carbon budget is the amount of carbon that we can afford to emit to keep the rise in global average temperatures below 1.5 °C". S. Teske is full of hope, believing that such opportunities still exist and global warming can be halted. He explains that 400 gigatonnes of CO2 can be emitted, and then "we must stay at 0". Otherwise, we will exceed the aforementioned 1.5 °C.