IPCCThe Working Group 1 (WG1) contribution to the Intergovernmental Panel on Climate Change (IPCC) 6th Assessment Report (AR6) is now well underway. It is important to note that the cutoff date for literature submission for inclusion in AR6 WG1 is 31st December 2019.

At the Global Climate Observing System (GCOS) Joint Planning Meeting in Marrakech this week, key observational needs were highlighted. The WG1 contribution includes a range of thematic chapters that require consideration of closure of important budgets and cycles such as the energy budget and the carbon and hydrological cycles. The WCRP Grand Challenges can clearly contribute substantially to these assessment activities.

Of particular importance is a need to better understand the distinction between global mean surface temperatures and global surface air temperatures. That is to say, the distinction between sea surface temperatures and near-surface air temperatures over the oceans. This has important implications for the global stocktake, the remaining carbon budget, and for where we stand today relative to pre-industrial times. There is no doubt that global surface air temperature change is greater than that of the global mean surface temperature. However, significant questions remain regarding the appropriate scaling factor to apply, at what scales it would be applicable, whether it is invariant with time, and its uncertainty. Literature contributions addressing this specific challenge would be most welcome.

To contribute please contact one of the authors listed under an appropriate chapter heading on the IPCC WG1 AR6 author list.