AdSense earnings decrease on https pages
Most people switched to https pages when Google anounced that they will display warnings in Google Chrome browser if pages don't start with https. It turns out this change is not very good for webmasters.
My AdSense earnings kept dropping each day to a point where in 2-3 months it got to 50% of what it was, I started looking around more into this, having AdSense on more than 10 sites it is kind of easy to look at what changed when the income drop started.
My conclusion ... the sites starting earning much less when https pages were enabled, the https vs http have more implications that you might be aware of, some of them are obvious, some of them I learned from other reports and I concluded they were valid.
On https pages AdSense only posts https compliant advertisers, images, links and other media that are valid for https pages, so on https there are less advertisers and competition can be lower, resulting in less ads (maybe less accurate to users) and paying less per click (because of less competition).
When you redirect all your site links from http to https that has an impact on search engine rankings, even if Google can properly follow a 301 permanent redirect, it will still need to re-index some of your pages and from my tests it shows that rankings and total amount of indexed pages ARE affected, at least temporary (weeks, months). Make sure you use Google Webmaster Tools and see the total amount of pages indexed, rankings and possible crawl errors.
https sites are usually slower, when servers need to encrypt traffic that results in a slower response to your visitors, that can cause fewer pages visited per user and also a decrease in search rankings.