Sending 65 emails releases approximately the same carbon emissions as driving 1km in your car. (Science Focus)
The point in writing this isn't to push you to stop communicating - we need to keep messaging - especially in these isolated times. However... make it count, and delete your rubbish too!
This article - Pointless Emails (the Guardian) - explains a little more about how and why your email is not so green.
To combat this - spend a bit of time filtering through your emails and deleting those ones that you just don't need (and empty your 'trash' after), and unsubscribe from emails that you are not interested in or not getting around to reading. Those emails sitting in storage 'in the cloud' are using up a server's energy somewhere in the world and chomping through electricity. Delete it and that ends.
Here's a song for you to enjoy while you delete all those cc's... Stop Copying Me Show of Hands