Note that forcing HTTPS will reduce your ad revenue. Google itself warns about it: "Some important things to know about the SSL-compatible ad code: HTTPS-enabl

Note that forcing HTTPS will reduce your ad revenue. Google itself warns about it: "Some important things to know about the SSL-compatible ad code: HTTPS-enabled sites require that all content on the page, including the ads, be SSL-compliant. As such, AdSense will remove all non-SSL compliant ads from competing in the auction on these pages. If you do decide to convert your HTTP site to HTTPS, please be aware that because we remove non-SSL compliant ads from the auction, thereby reducing auction pressure, ads on your HTTPS pages might earn less than those on your HTTP pages."