Monitoring of Geoengineering Strategies for Remediation of Global Warming Using Radiative Forcing

Wayne Evans NorthWest Research Associates, Inc.

Category: Radiation

Working Group: Aerosol Life Cycle

The importance of having an accurate monitoring system before commencing geoengineering (GEOE) projects such as SRM has been overlooked. The recent “climategate affair” has demonstrated that temperature is not adequate as the monitoring variable for global warming. Extensive debates over the accuracy of the temperature records have taken place. Ice melting has been used recently to demonstrate global warming but has a 25-year time lag. A variable with a fast response is needed to determine the current state of the global warming problem, let alone for modifications. The immediate response of adding greenhouses gases or aerosols to the atmosphere is a change in the climate radiative forcing (RF). This produces a temperature increase that lags behind RF by over 25 years due to the thermal inertia of water bodies. For GEOE the monitoring problem is more severe; the 25-year lag in temperature would make it difficult to monitor how effective a particular strategy would be. The time lag between RF and temperature response will be demonstrated. The noise in the temperature record further complicates its use to monitor the effectiveness of GEOE strategies. Similarly, water vapor lags RF by years since it is controlled by temperature. RF of gases can be measured at the surface with the AERI FTS instrument and at the top of the atmosphere with satellite instruments such as IASI. The shortwave spectral flux is also altered by aerosols. The use of current and planned satellites to monitor these changes will be described. The OSIRIS satellite results demonstrate that it would be feasible to set up an effective monitoring system for aerosol RF. GEOE should not be attempted without a monitoring system for RF in place. One might be working in the dark for 25 years without feedback from a fast-monitoring system. It is proposed to monitor the RF of global warming by GHG with a new network. The calibrated spectrum of greenhouse radiation at the surface has been measured and the RF flux from each greenhouse gas extracted. 14 AERI instruments, manufactured by ABB BOMEM, are deployed around the world. This network will provide a new experimental data set to complement the calculated RFs from climate models used for policy determination of safe levels of GHG. This network would support the U.S. DOE‘s long-term goal to deliver improved scientific data and models on the potential response of climate to increased GHG levels. The analysis of the data from ARM AERI sites would expedite a network to monitor RF. Although DOE has these valuable records of the ARM AERI data, it needs to process them into RF, a form suitable for release to the world community. The usefulness of RF over temperature is demonstrated by evaluating the present climate on the timeline of global warming. Our measurements show a total RF of 3.3 W/m2 from all GHG. Converting the 2 K Copenhagen target into RF shows that this is not achievable since only 8 years are left before RF will exceed the target.

This poster will be displayed at ASR Science Team Meeting.