What is the fine-grained topic of the following text: The theme of this year’s academy was “Sustainability at the Crossroads: Integrating Technologies, Policies and Strategies for a Sustainable Economy” – and it focused on the sustainability challenges facing us in the 21st century such as climate change, and solutions to address them such as renewable technologies, sharing economy, sustainable management of fisheries and food systems, and corporate sustainability policies. Only return the topic.
Sustainability challenges and solutions in the 21st century