The Rio ‘Earth’ Summit in 1992 was the “world’s biggest ever political gathering” with 108 heads of state or government. Its successes and failures on the environment and development continue to shape those debates.

In June, Rio de Janeiro will host the UN Conference on Sustainable Development, a.k.a. Rio+20. A very early draft document suggests it will cover a wide range of topics, including access to food, water and energy; marine litter and pollution; eliminating “market distorting and environmentally harmful subsidies […] including those on fossil fuels, agriculture and fisheries” (I’ll believe it when I see it); strengthening the UN Environment Programme (UNEP) and even the idea of an “Ombudsperson for Future Generations”. A set of “Sustainable Development Goals” may guide policies worldwide from 2015 to 2030.

While global warming and, indirectly, ocean acidification tend to hog the stage – even within our party – we also face many other forms of pollution, unprecedented extinction rates, harmful changes in land use, and the huge challenge of meeting the resource demands of an ever-growing and increasingly prosperous global population. Despite this, and calls from the Environmental Audit Committee and NGOs, and the summit having been postponed so as not to clash with the Queen’s jubilee, it has been reported that the PM is not intending to attend.

Why, if that proves true, should Nick Clegg not lead the delegation? Should any policy-making actually be necessary, he seems better qualified than Cameron. He once wrote a postgraduate thesis on “The Deep Green Movement and its Political Philosophy” and, more pertinently, co-wrote a paper in 2001 that discussed strengthening environmental agreements, their links to the WTO, and UNEP (all in the 2010 manifesto too).

But, admittedly, he hasn’t hugged any huskies.

His repertoire of languages would certainly serve him well and it would be good to have someone *ahem* who can build alliances with leaders from Europe and elsewhere. Do we really want Caroline Spelman as the UK’s highest representative, there to set a precedent and show the UK’s commitment to these issues? Low expectations of concrete action aren’t a reason to avoid involvement: they’re reason to strive harder.

I want Liberal Democrats – including Chris Huhne or Andrew George perhaps – there (and working in the run-up) to push for ambitious measures and internationalism; fighting poverty and ensuring markets account for externalities. The presence and input of the Deputy Prime Minister, however, would significantly raise the profile of these issues. What’s more, it would help establish that this is the greenest government ever, and that we are the greenest party of government ever.

* Adam Corlett is an economic analyst and Lib Dem member