Written by Sig Silber
With the big play from the White House tonight about an aggressive new program to combat climate change, it seems that the climate science community is taking a broader view of how to react to reduce global warming. Two new book length reports earlier this year reviewed existing data in a way that has not been done previously. These have not been widely noted and should be. The two reports:
- Carbon Dioxide Removal and Reliable Sequestration
- Reflecting Sunlight to Cool Earth
I was surprised when I saw this recent announcement from the The National Academies of Sciences - Engineering - Medicine:
"Climate intervention is no substitute for reductions in carbon dioxide emissions and adaptation efforts aimed at reducing the negative consequences of climate change. However, as our planet enters a period of changing climate never before experienced in recorded human history, interest is growing in the potential for deliberate intervention in the climate system to counter climate change. This study assesses the potential impacts, benefits, and costs of two different proposed classes of climate intervention: (1) carbon dioxide removal and (2) albedo modification (reflecting sunlight). Carbon dioxide removal strategies address a key driver of climate change, but research is needed to fully assess if any of these technologies could be appropriate for large-scale deployment. Albedo modification strategies could rapidly cool the planet's surface but pose environmental and other risks that are not well understood and therefore should not be deployed at climate-altering scales; more research is needed to determine if albedo modification approaches could be viable in the future."
In the process of doing this work two important decisions were made:
- One was to change the name of the activity to "Climate Intervention" for a number of reasons (it had been originally titled "Geoengineering Climate" ;
- The second was to avoid the idea that the level of existing knowledge was sufficient to describe it as an engineering discipline and to divide the work into two categories, as seen in the two reports. The reasons for the division are several but among them "there are vast differences in the research needs, and the extent of the environmental and social risks associated with the two classes of approaches".
There is an excellent summary "Report in Brief":
The full reports are well worth reading as they not only provide information on the two categories of approaches but also much information which or may not be in the IPCC AR5 WG1 but even if in there is better organized in these two reports: information that relates to measurement issues both with respect to Climate Change and assessing and monitoring the possible approaches that might be used to respond to Climate Change.
This is the first time that I have seen much discussion about approaches in addition to mitigation - which is actions to reduce emissions. It has seemed as if there was a concern that acknowledging that there are potential interventions might reduce the pressure to mitigate emissions. But apparently it is now believed that mitigation alone may not be sufficient.
The two full reports: