"Thanks for the pitch. It’s an interesting idea but unfortunately I have to decline. With current resources we’re only able to publish a small minority of the pitches we receive and while this idea has merit I’ve reluctantly decided there are others with stronger content."
Here are some of the topics they have not thought of sufficient interest. They have a common theme; limits to growth, existential risk to civilization, regional overload, the "fortress world" and philanthrocapitalism and planetary health.
The most recent rejection concerned existential risk. My paper (Climate change, health and existential risks to civilization: A comprehensive review (1989–2013)) showed that while the risk to civilization, and thus to global public health, from climate change has grown, the willingness to discuss this in the health literature has fallen considerably.
I know that the budget for the Conversation has fallen a lot in recent years.