Recent trends show that we will almost certainly exceed 1.5°C by the early 2030s, even if efforts to rapidly reduce emissions increase. In climate science, there is increasing discussion of “overshoot” – exceeding 1.5°C and then returning to it by the end of the century. Our factsheet by Andy Reisinger explains what the temporary temperature overshoot means for (ir)reversible consequences, what is needed to get back to 1.5°C and what needs to be done now to achieve this.