In tricky seats where constituents are getting in touch to complain about fracking, many MPs are getting understandably nervous.
Could fracking be one of the biggest casualties of the 2015 general election? Absolutely not, Lib Dems in Government insist.
This argument was shut down decisively at the party's autumn conference in Glasgow last year, they argue.
Well, up to a point, Lord Copper. It's true that delegates attracted scornful headlines by - the reports stated - decisively embracing both fracking and nuclear power.
The latest betrayal?
It's also true that the conference vote was viewed by many green-tinged observers as the latest betrayal from a party which had once placed environmental concerns at its core.
Actually, though, that's what ministers wanted you to think. The Lib Dem energy and climate change secretary, Ed Davey, is desperately keen to diversify Britain's energy mix by encouraging shale gas.
What he's not telling you about is the deep scepticism that's enduring among his party's grassroots.
A 'huge amount of disquiet' in the party
Now the Lib Dems are in the government, so the joke goes, they have taken to leaving their sandals in the cupboard at home when it comes to conference time.
That doesn't mean they've left behind the green credentials Lib Dems in government seem to have forgotten about. They are still very much there as far as voters are concerned, and that forces MPs to take them seriously as well.
"It wasn't a blanket 'yes' to fracking at all", says one prominent Lib Dem backbencher, Martin Horwood. "There is a huge amount of disquiet about fracking within the party."
What about the water?
Horwood has raised questions about the impact of fracking on the water cycle - the concern being that the vast quantities of water which are pumped into the earth as part of the hydraulic fracturing process doesn't return to normal circulation quickly enough.
The answers he's received from ministers so far have been completely inadequate, making it hard for him to by sympathetic to his colleagues in government.
"I'm trying not to have a knee-jerk anti reaction to fracking - despite all my instincts telling me I should. We have to be evidence-based about this."
Tim Farron: fracking's biggest Lib Dem enemy
But the highest-profile opponent of shale gas extraction within the party is the party's outgoing president, Tim Farron. He is as determined as Horwood to avoid getting into "utterly dogmatic support or opposition for any particular form of electricity generation".
But his opposition to shale gas, as he reaffirmed in his interview with The Ecologist, is uncompromising.
"We need to massively reduce our carbon footprint. Whilst I accept shale has a lesser carbon output than heavy coal, it's still a very large contributor to greenhouse gases.
"This issue is we're boxing ourselves in as a country to options which means we definitely won't meet our climate change targets, and we should take that very seriously."
In tricky seats where constituents are getting in touch to complain about fracking, many MPs are getting understandably nervous.
A radical shift to renewables
Like many Lib Dem activists, Farron wants a radical, rapid shift to renewables - and is frustrated by the small-scale approach of many green advocates.
He supports massive tidal schemes built in Britain's estuaries, like the Kent estuary in his Westmorland and Lonsdale constituency.
"The environment lobby have to understand there are no perfect solutions. We will have to destroy some ecosystems if we want to build tidal schemes. If you're going to be against fracking, you've got to be prepared to have tidal schemes built."
Different kinds of pragmatism
But something has happened to Liberal Democrats in government to blunt their commitment to all things green.
One minister I spoke to, not in Davey's department, shrugged his shoulders when I asked about fracking: "I've not got a problem with it - we've got to get our energy from somewhere."
That attitude prevails at DECC, too. "We need a lot of gas in this country for a long time", one senior departmental adviser to Davey said.
"Either we continue to increase the amount of gas we import, and that has an obvious carbon footprint, or you look at homegrown gas. There's a positive carbon footprint argument to be made there."
Maybe it's pressure from civil servants. Perhaps they have assimilated a more Conservative mindset from their coalition partners. Or perhaps it's down to fear that if the proverbial lights go out, they will pay a heavy electoral price.
But whatever it is, something has made Lib Dems in Government forget that taking any more fossil fuel out of the ground will imperil the 2C target.
An electoral price to pay
But the change in atttitude has not filtered through to the Lib Dem backbenches. In Whitehall, winning over disgruntled Lib Dems is put in the same category as winning over the general public to fracking's charms.
They don't understand, the minister added, that the Environment Agency is putting in place "extremely tight world-leading regulations". All that's needed, he maintained, is a big "comms job".
But Lib Dems aren't like the general public. This is a party which has been deeply committed to the environment for years. And its MPs know there will be an electoral price to pay if it abandons its green credentials now.
Their jobs are on the line
Most of Nick Clegg's backbenchers, unable to rely on their 'protest vote' status, now find themselves in marginal seats which they will be hard-pressed to hold on to.
The tuition fees betrayal was bad enough. In tricky seats where constituents are getting in touch to complain about fracking, many MPs are getting understandably nervous.
While the Government is thinking long-term about our future energy supply, Lib Dem MPs are worried that their jobs are on the line - because their voters are thinking even longer-term about this planet's future.
Fracking endangered?
The paper-thin support for shale gas extraction among the Lib Dem grassroots is a long way from the solid approval projected by the party's ministers.
In the 2013 Lib Dem party conference in Glasgow, fracking's opponents say, Lib Dems didn't want to "make life difficult" for Davey - and so they let the fracking motion go through.
A survey for Lib Dem Voice of party members found only 46% backed fracking - with 36% against it and 17% undecided.
The website's editor, Stephen Tall, says the party is taking a "pragmatic" view of shale gas extraction - neither embracing nor rejecting it outright.
"More than a third of members (36%) are opposed. Clearly as a relatively new technology, pretty much untested at scale within the UK, there is much more caution."
Will the green light turn to red?
It begs the question: if the Lib Dems are thrown into turmoil by a disappointing election result in 2015, could the current green light for shale gas extraction turn red?
"Conference probed itself to be agnostic on nuclear and shale gas - OK", Farron says. "The problem is in difficult economic times being green is seen as ludicrous ... it's a question of having the will to do it."
Farron is hotly tipped by many to be the next Lib Dem leader. If the party stumbles in the 2015 elections and Clegg is forced out of power, his successor could be ready to make a decisive move away from fracking.
And as the Tories and Labour slog it out, the Lib Dems appear likely once again likely to play a critical role after the 2015 election - even if they have many fewer seats than the 56 they have now.
There is a better than sporting chance that the UK's 'frack baby, frack' policy may not survive 2015.
Alex Stevenson is parliamentary editor of politics.co.uk.
