Protest and direct action could be the only way to tackle soaring carbon emissions, a leading climate scientist has said.

James Hansen, a climate modeller with Nasa, told the Guardian today that corporate lobbying has undermined democratic attempts to curb carbon pollution. "The democratic process doesn't quite seem to be working," he said.

Speaking on the eve of joining a protest against the headquarters of power firm E.ON in Coventry, Hansen said: "The first action that people should take is to use the democratic process. What is frustrating people, me included, is that democratic action affects elections but what we get then from political leaders is greenwash.

"The democratic process is supposed to be one person one vote, but it turns out that money is talking louder than the votes. So, I'm not surprised that people are getting frustrated. I think that peaceful demonstration is not out of order, because we're running out of time."

Hansen said he was taking part in the Coventry demonstration tomorrow because he wants a worldwide moratorium on new coal power stations. E.ON wants to build such a station at Kingsnorth in Kent, an application that energy and the climate change minister Ed Miliband recently delayed. "I think that peaceful actions that attempt to draw society's attention to the issue are not inappropriate," Hansen said.

He added that a scientific meeting in Copenhagen last week had made clear the "urgency of the science and the inaction taken by governments".

Officials will gather in Bonn later this month to continue talks on a new global climate treaty, which campaigners have called to be signed at a UN meeting in Copenhagen in December. Hansen warned that the new treaty is "guaranteed to fail" to bring down emissions.

Hansen said: "What's being talked about for Copenhagen is a strenghening of Kyoto [protocol] approach, a cap and trade with offsets and escape hatches which will be gauranteed to fail in terms of getting the required rapid reduction in emissions. They talk about goals which sound impressive, but when you see the actions are such that it will be impossible to reach those goals, then I can understand the informed public getting frustrated."

He said he was growing "concerned" over the stance taken by the new US adminstration on global warming. "It's not clear what their intentions are yet, but if they are going to support cap and trade then unfortunately i think that will be another case of greenwash. It's going to take stronger action than that."