  While an astronomer's job is typically to look out from Earth, the
seriousness of the climate crisis has meant a shift in many astronomers' focus.
Astronomers are starting to consider how our resource requirements may
contribute to this crisis and how we may better conduct our research in a more
environmentally sustainable fashion. Astronomers for Planet Earth is an
international organisation (more than 1,700 members from over 70 countries as
of November 2022) that seeks to answer the call for sustainability to be at the
heart of astronomers' practices. In this article, we review the organisation's
history, summarising the proactive, collaborative efforts and research into
astronomy sustainability conducted by its members. We update the state of
affairs with respect to the carbon footprint of astronomy research, noting an
improvement in renewable energy powering supercomputing facilities in
Australia, reducing that component of our footprint by a factor of 2--3. We
discuss how, despite accelerated changes made throughout the pandemic, we still
must address the format of our meetings. Using recent annual meetings of the
Australian and European astronomical societies as examples, we demonstrate that
the more online-focussed a meeting is, the greater its attendance and the lower
its emissions.
