 So I thought the Earth system rate of change is something good because we can look at this. It's something we can measure the various components of the biodiversity as part of the Earth system, changes to the ice sheets, changes to the oceans, changes to biogeochemistry, changes to the atmospheric concentrations of greenhouse gases, the key components of the Earth system that keep it functioning. We can measure the rate of change there for each one of those and compare that to Earth.