Central banks might more often encounter the zero lower bound on nominal rates, which would imply less room to maneuver the policy rate to counteract deflationary shocks. The economy would be less resilient to negative shocks. Central banks might have to increasingly resort to what we call unconventional policies.
But we do not know how effective these tools are as a normal business cycle stabilizer, and what macroeconomic risks they might entail. Let me conclude signaling another risk. Economic policies became exceptionally accommodative after the financial crisis in order to save the world from another Great Depression.