Very few Earth System Models (ESMs) has considered phosphorus (P) as a limiting nutrient, although P limitation is widespread and is most pronounced in highly productive lowland tropical forests. In this task (land task M3.12) we will further develop and improve the existing CLM4-CNP model and integrate the improved prognostic P cycle model into the ACME land model. The objective is to examine how the inclusion of prognostic phosphorus (P) cycle affects carbon-climate feedbacks using fully coupled simulations. Here we will present results from the offline global CLM4-CNP simulations to show the role of P in affecting ecosystem responses to changes in atmospheric CO2 and climate. We will also present some preliminary results from the site-level simulations using P-enabled ACME land model.