scare·mon·ger (skâr′mŭng′gər, -mŏng′-) n.
One who spreads frightening rumors; an alarmist.
scare′mon′ger·ing n. (from: the Free Dictionary.)
Example of usage:
"The leaders of the local protest group spent a significant amount of efforts to galvanise local opposition, using rhetoric which pro-development stakeholders might call ‘scaremongering’ (it should be pointed out that we noted comparable ‘scaremongering’ tactics coming from a developer; Borders Biofuel first tried to ‘sell’ their fast pyrolysis plant in Wales on the basis of new employment, but when public opposition became stronger, they began to argue that jobs in the existing sawmill were likely to disappear if the proposal was not accepted).
It would be hard to prove that the initiators of the local protest do not fully believe their own rhetoric when they start off, but as they learn about the novel technology, these protest leaders must review this list of potential impacts and decide which ones are more ‘scientifically robust’ and/or more consistent with planning regulations, thus providing more powerful arguments in the formal planning debate.
However, these arguments may not be as powerful in the continued harnessing of public support to put pressure on elected local councillors. These leaders may thus end up in a situation where they are singing from two different hymn sheets." (van der Horst, 2007: 2711)
van der Horst, D. (2007). NIMBY or not? Exploring the relevance of location and the politics of voiced opinions in renewable energy siting controversies. Energy policy, 35(5), 2705-2714.
There you go.