There are a number of papers that support the idea that reflecting solar energy back out into space would offset the warming effect of atmospheric CO2. For a high-level overview of how it works and the state of the research, check out this GCCA Issue Brief. GCCA regularly publishes Issue Briefs on hot topics covering cool roofs and urban heat islands. This recent article in the San Francisco Chronicle also does a nice job summarizing the opportunity.
If you really want to dig into the details, check out the following papers in our Knowledge Base:
Global Cooling Updates
The Long Term Impact of Increasing Albedo in Urban Areas
Global and Local Effect of Increasing Land Albedo
Regional Climate Consequences of Large-Scale Cool Roof and PV Deployment
Effects of Urban Surfaces and White Roofs on Global and Regional Climate
LBNL Response to Jacobsen and Ten Hoeve (2011)