Liberal Democrat leader Sir Menzies Campbell has accused Gordon Brown of showing "complacency" towards the environment in his Budget.
In his Budget response he also said Mr Brown had failed to tackle "unfair tax" or deal with pensions problems.
Sir Menzies said that, "with low inflation and stable employment", the chancellor had had the opportunity "to show his worth".
But he had "declined" to deal with any of his major problems.
'Help not deserved?'
In his Budget speech, Mr Brown said he wanted to encourage energy efficiency in the business sector through an increase in the climate change levy rate, in line with inflation from 1 April next year.
He announced a further £50m to help boost the installation of microgeneration technologies, including micro wind turbines and solar heating in homes, schools, businesses, public buildings and social and local authority housing.
A £1bn energy and environmental research institute was being set up, Mr Brown said.
Meanwhile, a quarter of a million extra homes would be insulated over the next two years.
However, Sir Menzies criticised the chancellor for not imposing higher taxes on polluters.
He said: "This Budget was an opportunity. In a period of relative stability with low inflation and stable employment, the chancellor had an opportunity to show his worth.
"He could have tackled the unfair tax system. He could have made the environment a priority.
"He could have faced up to the pensions crisis. He could have addressed the problem of personal debt.
"He's declined to do any of these. This is a legacy from which it will be difficult for him to escape."
Sir Menzies asked why last year's £200 council tax rebate for pensioners had not been repeated this year.
He said: "Why was it they deserved help before a general election but don't deserve it a year later?"
Sir Menzies said the issues of personal debt and the pensions crisis were glaring omissions from the Budget.
He said: "Consumer debt is now approaching £1.2 trillion, practically identical to the gross domestic product of the UK as a whole.
"Consumer debt has underpinned the economic boom, but the legacy for so many families will be disaster. Nearly a fifth of all income is now being used to service debt.
"That means it is back to the level it was when the economy crashed under the Conservatives in the early 1990s."