Every so often we will post chunks of sociological/political theory.  Don’t worry if you’re allergic to ‘em – we will flag up what we are doing.  This below is from a recent book called “Social Movements” by Suzanne Staggenborg, Oxford University Press 2008

Public interest in the environment and membership in environmental organizations has ebbed and flowed over the years, as has media attention to environmental issues. Anthony Downs (1972) argues that there is an “issue attention cycle” whereby the public becomes alarmed about a problem and very concerned with its amelioration. Once the public comes to realize the cost of significant progress, however, enthusiasm for solutions to the problem dampens. Eventually, a decline in public interest is followed by a ‘post-problem phase’ during which the problem may sporadically recapture public interest. In 1972 Downs wrote that the public was already starting to realize the enormity of the social and financial costs involved in cleaning up the environment.
Page 106

The graph at the top of the quote comes, I think, from the following article.