Article

Climatic Change

, 109:77

First online:

Open Access This content is freely available online to anyone, anywhere at any time.

RCP4.5: a pathway for stabilization of radiative forcing by 2100

  • Allison M. ThomsonAffiliated withJoint Global Change Research Institute, Pacific Northwest National Laboratory and the University of Maryland Email author 
  • , Katherine V. CalvinAffiliated withJoint Global Change Research Institute, Pacific Northwest National Laboratory and the University of Maryland
  • , Steven J. SmithAffiliated withJoint Global Change Research Institute, Pacific Northwest National Laboratory and the University of Maryland
  • , G. Page KyleAffiliated withJoint Global Change Research Institute, Pacific Northwest National Laboratory and the University of Maryland
  • , April VolkeAffiliated withJoint Global Change Research Institute, Pacific Northwest National Laboratory and the University of Maryland
  • , Pralit PatelAffiliated withJoint Global Change Research Institute, Pacific Northwest National Laboratory and the University of Maryland
  • , Sabrina Delgado-AriasAffiliated withJoint Global Change Research Institute, Pacific Northwest National Laboratory and the University of Maryland
  • , Ben Bond-LambertyAffiliated withJoint Global Change Research Institute, Pacific Northwest National Laboratory and the University of Maryland
  • , Marshall A. WiseAffiliated withJoint Global Change Research Institute, Pacific Northwest National Laboratory and the University of Maryland
    • , Leon E. ClarkeAffiliated withJoint Global Change Research Institute, Pacific Northwest National Laboratory and the University of Maryland
    • , James A. EdmondsAffiliated withJoint Global Change Research Institute, Pacific Northwest National Laboratory and the University of Maryland

Abstract

Representative Concentration Pathway (RCP) 4.5 is a scenario that stabilizes radiative forcing at 4.5 W m−2 in the year 2100 without ever exceeding that value. Simulated with the Global Change Assessment Model (GCAM), RCP4.5 includes long-term, global emissions of greenhouse gases, short-lived species, and land-use-land-cover in a global economic framework. RCP4.5 was updated from earlier GCAM scenarios to incorporate historical emissions and land cover information common to the RCP process and follows a cost-minimizing pathway to reach the target radiative forcing. The imperative to limit emissions in order to reach this target drives changes in the energy system, including shifts to electricity, to lower emissions energy technologies and to the deployment of carbon capture and geologic storage technology. In addition, the RCP4.5 emissions price also applies to land use emissions; as a result, forest lands expand from their present day extent. The simulated future emissions and land use were downscaled from the regional simulation to a grid to facilitate transfer to climate models. While there are many alternative pathways to achieve a radiative forcing level of 4.5 W m−2, the application of the RCP4.5 provides a common platform for climate models to explore the climate system response to stabilizing the anthropogenic components of radiative forcing.