Constant calls for evidence-based policy miss the underlying politics of knowledge, argues analyst Peter Bille Larsen.

How scientific knowledge is presented in public debate, by scientists or journalists, has a big influence on its impact, says David Dickson.

An ambitious strategy to create fuel cell products for export will need incentives and cross-government backing to bear fruit, says Radhika Perrot.

Although the region is not a big polluter, the threat of climate change means it should lead the way on cuts, argues Crispin Maslog.

Journalists can help the developed world take responsibility for climate change by making it relevant to readers' lives, says David Dickson.

Using the human rights framework to tackle challenging ethical questions can guide climate policy, argues political philosopher Simon Caney.

Algal biofuels, like crops, demand land, water, fertilisers, pesticides and inputs that are costly for India, says Hoysall Chanakya.

Sustainable development targets will work only if they engage with the realities of national politics, says policy expert Matthew Lockwood.

The contribution of tropical hydropower plants to global warming should be included in national inventories, say P. Fearnside and S. Pueyo.

Forecast to be underwater by 2050, the Pacific island states must plan for climate adaptation, with global support, urges Crispin Maslog.

The concept of environmental thresholds could weaken progress on sustainability at Rio+20, says global change scientist Simon L. Lewis.

Rio+20 must launch SDGs to guide countries through complex development challenges, argues Colombian ministry official Paula Caballero Gómez.

Pakistan urgently needs to refine its crop yield forecasting and estimation system to improve food production, says Ibrar ul Hassan Akhtar.

Climate change could benefit some Pacific fisheries, but tracking the success of adaptation needs effective monitoring, says Johann Bell.

Desertec, an ambitious solar power project in the Middle East and Africa, should be more transparent and participatory, argues Athar Osama.

The hydrological ecosystem services of Amazonian forests must be valued, says conservation biologist Carlos Peres.

Cities are vulnerable to climate change but can adapt with policymaking informed by sound science says Cynthia Rosenweig and colleagues.

Policymakers must find flexible plans to ensure water security despite the uncertainties of climate change, says climate scientist Mark New.

The challenge for Latin American and Caribbean governments is to combine an approach to development with low-carbon emissions, says Omar Vidal.