Google answered in their adsense forum.
The changes are permanent!
Thank you google, I cant feed my children now. Bravo.
Do no evil right? A 50% cut in revenue, just like that, plenty of time for families to adapt!
"You're correct. The ad formats have changed as of Friday the 9th. Here's some quick Q&A that might help answer your questions:
Q. Why is the button no longer on my website?
A. Our systems have determined that some ad elements in text ads implemented on your site are not performing well for users, advertisers, and/or the publish network, therefore, the arrow button may not display on your ads moving forward. Different ad elements may or may not appear in text ads depending on what is deemed best performing for users, advertisers, and publishers. We believe these changes will encourage advertisers to spend more on the network, and lift earnings for our publisher clients in the long term.
Q. Why has my CTR gone down?
A. Clicks/CTR are largely a factor of ad type, ad rendering and ad placement amongst others. Depending on the performance of an ad unit we may change how ads are rendered to prevent accidental clicks. You may want to check your ad implementations as they may be causing users to take unintended actions. Please see How you can help to prevent invalid activity for more.
There's no rollback planned so I'd think about investing in a new layout if you think your layout is not optimal for the current ad styles."