At the direction of Congress, NOAA is leading a new, multi-year research initiative to investigate natural and human activities that might alter the chemistry and reflectivity of the stratosphere or the reflectivity of the marine boundary layer through the addition of aerosols, and to understand the potential impacts on the Earth system. These activities include proposed climate intervention approaches to influence climate warming by reflecting sunlight from the atmosphere, which require extensive scientific research and assessment.
During the initial year of the initiative, NOAA has established three primary research goals:
Improving our understanding of the energy balance of the Earth system
Establishing a capability to observe and monitor stratospheric conditions
Detecting and accurately simulating the impacts of natural and human-caused aerosol injections in the stratosphere and troposphere on Earth’s radiation balance, weather and climate patterns, and other Earth systems
Funding for Fiscal Year 2020 supported three types of research projects:
Illustration [Eastham, S., S. Doherty, D. Keith, J. H. Richter, and L. Xia, Improving models for solar climate intervention research, Eos, 2021] of proposed methods for climate intervention that would affect climate by modifying either incoming or outgoing solar radiation.
The first is to develop observational methods to understand baseline aerosol conditions in the stratosphere.
Initial observations using instrumented balloons have already started
New instruments are being developed for future stratospheric aircraft campaigns
Laboratory studies will be initiated to investigate potential stratospheric solar radiation management (SRM) materials
Second, models of stratospheric and tropospheric responses to increases in stratospheric aerosol loading are being developed and improved.
Third, model investigations are also exploring the potential for aerosol injections to increase the reflectivity, or brighten, low-altitude marine clouds.
The research is designed to support improved observation and assessment of stratospheric processes and Earth's radiation budget as a part of NOAA's mission to support public safety and environmental sustainability. These projects are geared both towards producing immediate results and building a foundation for future research.
Potential work in subsequent years could include:
Expansion of balloon observations
Field mission deployment of stratospheric aircraft instruments
Further lab testing of possible SRM materials
Model studies taking advantage of improvements in the representation of aerosols developed with FY20 funds