evidence: Each method can offer a slightly different estimate of current warming, depending on which data, algorithms and assumptions are used. Nonetheless, there is broad agreement on some things, such as that warming in 2022 was about 1.24 °C (with an uncertainty range between 1.0 °C and 1.6 °C), and that 1.0 °C warming was exceeded around 2011 or 2012. There have been times when the differences between methods were greater, either because the rate of warming changed rapidly so a linear trend did not represent the long-term change, or because large natural variability led to a difference between the observed warming and the human contribution. For example, there is less agreement on the year in which 0.5 °C of warming was exceeded, put at some time between 1982 and 1988. This demonstrates the potential for confusion on recognizing the crossing of 1.5 °C if a single indicator is not agreed. [...] The IPCC should examine indicators such as ours in depth. If a suitable metric is agreed, a robust and transparent process for calculating and communicating it should be developed. It should make use of well-established sources and practices as far as possible. For example, observations could come from the WMO’s State of the Global Climate report (go.nature.com/3qqngme), and projections or forecasts could use the IPCC’s assessed warming rates8 and the WMO’s decadal forecasts.