The Department of Energy and Climate Change (DECC) has been targeted by environment campaigners as the week-long Climate Camp comes to a close.

Campaigners sat in kayaks wearing arm bands and goggles outside the department's central London headquarters on Wednesday in objection to what they termed the government's "false solutions" to climate change, such as carbon trading.

Activist Jane Roberts said: "We thought that DECC's staff and [secretary of state] Ed Miliband might appreciate some goggles and floats, because if they continue with their destructive policies they will need them.

"It really is 'sink or survive' for the future of humanity now. Climate change is being caused by the same economic and political system that has caused the economic meltdown.

"Rather than getting serious about tackling climate change, DECC is simply seeking to preserve these failed systems with false solutions, such as carbon trading."

Another activist, Hassan Beg, accused the department of having a "vested interest" in the coal industry. "It is no coincidence that they are promoting unproven carbon-capture and storage technology to justify E.ON building a new dirty coal-power station at Kingsnorth and a new generation of open-cast coal mines.

"One can't help wondering whether the Vestas wind turbine factory would have been given the financial assistance necessary to stay open if it had been coal."

A DECC spokesman said: "We all value our freedoms to speak out, gather together and demonstrate. This action has not disrupted the department's work to fight climate change and safeguard the nation's energy security.

"We are the first country in the world to set out a comprehensive plan to cut our emissions - by at least a third by 2020. Our action here will help us push for an ambitious global deal at Copenhagen to tackle global warming."