By Oliver Hayes
Climate change - the issue David Cameron described a year ago as "one of the most serious threats that this country and this world faces" and on which all three leaders signed an important pledge as recently as February – has been studiously avoided in this campaign. Green issues recently topped a list of issues the public feels have been too much ignored.
That leaves people interested in the environment only having the party manifestos to turn to as their sole indication of what each party plans.
So what do the 2015 manifestos reveal of parties' plans to tackle emissions, restore nature or use precious natural resources more wisely? Here's a run-down of their highs and lows.
Conservatives: More of the same
The Conservatives have a poor record on the environment in office, launching a dash for fossil fuels including massive tax breaks for fracking and North Sea oil and gas. Their manifesto shows they offer more of the same.
The party promises a "significant expansion in new gas" including support for fracking, rules out a target for carbon free power and pledges to "halt the spread of subsidised onshore wind farms". To be clear, banning onshore wind farms means ruling out the cheapest form of renewable energy, which somewhat undermines their very next pledge - a commitment to cut carbon emissions "as cheaply as possible".
On the plus side, David Cameron's commitment to end the use of unabated coal for power generation is very welcome. He should make clear that this dirty fossil fuel will be off our system by 2023 in line with Department of Energy and Climate Change projections.
Labour: Hooked on fossil fuels
The Labour party manifesto includes some good environmental commitments but Labour is still too supportive of fossil fuels.
A legal target to remove carbon from our electricity supply by 2030 is great, as is the commitment to a million new green jobs. And a Lord Stern-style review of the economic impact of resource use (and misuse) to be led by the Treasury could be a game-changer.
But the boost for offshore oil and gas ("a long-term strategy for the industry, including more certainty on tax rates") signals continued and worrying backing for fossil fuel extraction.
Labour's position on fracking has strengthened since the manifesto publication, with Caroline Flint ruling out any fracking until all of their 13 regulatory conditions are on the statute books. If they're serious about going green though, Labour should promise to ban fracking altogether. The accepted need to keep 80% of known fossil fuels in the ground is not compatible with a fracking boom, however tough the regulations.
Liberal Democrats: Talk doesn't match actions
Despite their green talk, Liberal Democrats failed to sufficiently stand up to the Conservatives in office. Their manifesto has some bold environmental commitments but they are still too wedded to fossil fuels.
Like the Labour party, Lib Dems have done the right thing by promising a 2030 "decarbonisation target" (even though they voted against it in the 2013 Energy Bill) and pledging to ditch dirty coal.
Perhaps their most striking announcement is on aviation: "No expansion of Heathrow, Stansted or Gatwick and any new airport in the Thames Estuary" and "no net increase in runways across the UK" is good news for the climate and air pollution.
The Lib Dems were first out of the blocks with a "Stern for resources" report, and deserve much credit for it. It could be improved by being Treasury-led, as Labour has pledged.
Significant downsides remain though, notably the party's unqualified support for fracking and the EU-US free trade deal TTIP.
SNP: Jekyll and Hyde
Their likely status as Britain's third biggest party on May 8th means the SNP could have a big say in shaping the next government's green outlook.
They appear no less prone to the Jekyll and Hyde approach to green issues than other parties, with a 100% renewables pledge, and a ban on fracking, sitting incongruously alongside a promise to "keep the pressure on the UK Treasury to do all it can to protect… investment in the oil and gas industry".
Others: From one extreme to the other
At opposite ends of the spectrum, it's not surprising that the Greens have an excellent and comprehensive suite of environment policies, while Ukip offer measures that, if implemented, would spell disaster for the planet.
So despite the enviro-silence of the national campaigns, it's clear that parties offer substantially different approaches. Only the Greens, however, come anywhere close to meeting the standard we believe necessary to address the greatest environmental challenges we face.
Of the big two, there is no doubt that Labour's manifesto is much greener than the Conservatives', although the party remains too committed to fossil fuels and high carbon infrastructure.
Whoever's in charge come May 8th, unless they put climate change at the heart of their programme for office the UK will be building up huge economic and ecological problems for the future.
Oliver Hayes is a political campaigner at Friends of the Earth
The opinions in Politics.co.uk's Comment and Analysis section are those of the author and are no reflection of the views of the website or its owners.