Presentation Information
[O07-01]Changes in surface radiation budget due to global warming★Invited Papers
*Michio Kawamiya1 (1.Japan Agency for Marine-Earth Science and Technology)
Keywords:
global warming,radiation budget,feedback,carbon dioxide
The radiation balance at the Earth's surface is maintained by an equilibrium between the incoming solar energy and the outgoing energy emitted by the Earth. Around 30% of solar energy is reflected by clouds, ice and snow on the surface, while the remaining 70% is absorbed by the atmosphere and the Earth's surface, thereby heating the planet. The warmed surface then emits infrared radiation. While some of this radiation escapes directly into space, much of it is absorbed by greenhouse gases, such as carbon dioxide, in the atmosphere and re-emitted towards the Earth's surface or into space. In a steady state, the incoming and outgoing radiation balances out. However, the current increase in greenhouse gases reduces the amount of energy finally escaping into space, creating an energy imbalance whereby heat accumulates at the Earth's surface — this is global warming. The presentation will also introduce various feedback processes, such as water vapour feedback, whereby increased carbon dioxide concentrations trigger an increase in atmospheric water vapour, thereby accelerating warming. It is hoped that the presentation will enhance understanding of the fundamental processes underlying global warming.