A green arrow at the bottom of an ECAM E/WD memo section indicates:

A green arrow appearing at the bottom of the ECAM E/WD (Engine/Warning Display) memo section signifies that there is more than one page of alert messages available for display. This indicator is important for pilots, as it prompts them to scroll through the messages to ensure they are fully aware of all relevant information regarding the aircraft's status and any potential alerts that may affect operations.

The ability to scroll through additional messages is crucial for situational awareness, allowing pilots to respond appropriately to any ongoing issues or alerts. It is a vital part of managing the aircraft's systems effectively and ensuring safety.

The other options do not accurately represent what the green arrow indicates. For instance, descending due to a malfunction or being low on fuel does not necessitate additional pages of information in this context. Similarly, while there is indeed additional information available on the lower ECAM screen, this is not what the green arrow specifically denotes. The arrow's purpose is to alert the pilot to the availability of further messages on the existing display.