Climate System Science has come a long way since 1990 when the First Assessment Report concluded “emissions from human activities … will result on average in an additional warming of the Earth’s surface.” Warming was “unequivocal” by 2007 and it’s a little hard for the 5th assessment report to be clearer than that. Through this process climate models have evolved from mixed layer oceans and land surface buckets to near eddy-resolving oceans, without flux correction and land models that couple energy, water and carbon at the stomata and include nitrogen limitation.

So, where to now? What do we want our climate models to be able to do? What does the research community need to do to build this capacity? What is the balance between a model with the capacities we want, and our capacity to use the model? How does our science demands interweave with our skills and capacities and with the technical developments on the horizon?

My goal is to present one perspective on what we want from a global climate model in the framework of what we think is possible, what we think is necessary and what we think is usable. I will try to focus on the pathway to CMIP-6 highlighting those areas that might limit our ability to deliver what we want.