Another climate conference; a few more tiny, acrimonious steps taken towards a global deal to cut carbon. As always, the 19th conference of the parties at Warsaw seemed like too little, too late.

But in one area there was an uncharacteristic outbreak of progress. Seven crucial decisions were approved, finalising a global framework for paying developing countries to protect their forests – otherwise known as REDD+. On top of this, the UK, Norway, the US and Germany put $280 million into the World Bank Bio-carbon fund for REDD+.

That’s not to say that everyone is happy with the outcome. The talks were marred by a dramatic walk-out of many delegates in protest at an attempt by Papua New Guinea, on behalf of the Coalition of Rainforest Nations, to re-insert an amendment that had previously been deleted.

The trouble with REDD+ is that it’s a great idea in theory, but highly controversial in practice. It offers the tantalising prospect of protecting rapidly disappearing tropical rainforests, rich in stored carbon, and achieving a vast range of co-benefits. As well as being hotspots of biodiversity, tropical forests prevent soil erosion, provide clean water, regulate regional rainfall patterns and provide homes and livelihoods for indigenous people.

But there are numerous problems in actually achieving these co-benefits in practice. For one thing, the indigenous people who should benefit most from REDD+ have often been marginalised, seeing the rights to their homeland traded away without the necessary “free, prior and informed consent.”

A further set of problems lurk in the innocent-sounding “+” at the end of the REDD+ acronym, which stands for – wait for it – “reducing emissions from deforestation and forest degradation, plus measures to conserve and enhance forest carbon stocks and promote sustainable forest management“. The bit after the “plus” refers to planting new forests, re-foresting previously cleared forests, or changing the way in which extraction of forest resources is managed. There is concern that the scheme could be used to subsidise commercial plantations, even perhaps indirectly encouraging the felling of native forests with a view to establishing subsidised oil-palm plantations on the land later.

The next barrier is the difficulty of monitoring and verifying the carbon emission reductions achieved. How do we know that a forest would have been felled if the payments were not made? And if we direct funding towards the countries where forests are most at risk of felling, are we not penalising the countries that have already taken the decision to protect their forests? What happens if the carbon stored in a REDD+ forest is lost or damaged due to fire, disease, illegal logging or climate change? How do we estimate the amount of carbon stored anyway?

Great progress has been made on all of these issues over the last decade. Satellite technology has improved monitoring and verification, and a comprehensive set of safeguards has been devised to ensure that indigenous people retain their rights and livelihoods, and that biodiversity is conserved. The rules set at Warsaw  specify that countries cannot receive money under REDD+ until they report on how social and environmental safeguards are being implemented.

The battle to strengthen REDD+ safeguards is certainly not over yet. At next year’s climate conference in Lima, delegates will decide exactly what information goes into the reports on safeguards. And despite all the progress over the last few years, one expert believes that the only truly successful REDD+ deal to date is the Surui project in Brazil, where the local indigenous tribe are leading the project.

But perhaps the greatest concern is that REDD+ will distract attention from the need to reduce carbon emissions from fossil fuels. The main source of finance is currently voluntary carbon offsets bought by companies, and opponents argue that this gives companies an excuse to carry on polluting. Even if REDD+ was incorporated into an international carbon cutting agreement, such as a cap-and-trade mechanism, some observers fear that the availability of relatively cheap forest carbon credits could drive down the price of carbon, removing the incentive to invest in low-carbon energy and energy efficiency measures. Or that without a global agreement on forest protection, deforestation could simply shift elsewhere.

This emphasises that we need a very carefully designed regulatory framework, to make REDD+ work without diminishing fossil fuel reduction policies. If we can achieve this, we can gain a vast range of co-benefits – cutting pollution, safeguarding biodiversity and protecting local livelihoods.