Hard forks don't require any particular adoption percentage (unlike soft forks). The network simply splits in two chains. If one of the chains is obviously weak

Hard forks don't require any particular adoption percentage (unlike soft forks). The network simply splits in two chains. If one of the chains is obviously weaker, it usually dies quickly, as it's no longer economically viable. In this case the sentiment among actual ETH holders is ~ 85% in favor of the hard fork. Check http://carbonvote.com/ http://carbonvote.com/ (it's not a binding vote, just an indication showing which way the wind blows).