Did you know that forests cover around 4 billion hectares or around 30% of the Earth's total land area? But did you also know that the world's forests are disappearing rapidly due to continued demand for timber and agricultural land as well as urban development? Forests are significant sinks of carbon. When destroyed, they emit carbon dioxide into the atmosphere. Dealing with the destruction of forests is therefore critical to combat and climate change. This is especially true for tropical forests such as the Amazon and those in Papua New Guinea and Indonesia which are amongst the most carbon dense and at-risk ecosystems in the world. Traditional approaches to halting forest loss, such as the establishment of protected areas, have been largely unsuccessful due to a lack of consideration of the socio-economic aspects of forest use. Now protected areas are important, but their effectiveness is limited if the needs of communities that derive their livelihoods from forest resources aren't addressed. Therefore new complementary mechanisms are needed if we are to create an incentive to keep forests intact. Enter REDD or RED which stands for reduced emissions from deforestation and degradation. REDD is a voluntary approach to climate change mitigation developed by the United Nations Framework Convention on Climate Change. It provides a framework that financially rewards developing countries for achieving emissions reductions through a decrease in deforestation. So how does REDD work? Well, having identified current and projected rates of deforestation and degradation, a country takes remedial action, for example by giving up logging rights. That country will then be financially rewarded for the resulting avoided emissions. To date, the funding for REDD projects has mainly come from national or local governments, nonprofit organisations and the private sector. An example is the Norwegian Government's International Climate and Forests Initiative which has pledged around $500 million US dollars per year to initiatives that reduce emissions from deforestation. It's worth noting that REDD-type projects have also been undertaken using market-based carbon offset mechanisms, such as the verified carbon standard. So that's REDD in a nutshell. You may also hear people talking about REDD+. The PLUS means that a REDD project also involves the enhancement of forest carbon stocks and not just stopping deforestation. Proponents emphasise that the REDD PLUS programme has the potential to contribute to important co-benefits in parallel with climate change mitigation. These co-benefits include poverty alleviation, biodiversity conservation, and sustaining vital ecosystem services such as water purification through erosion prevention. Now, REDD was first proposed in 2005, but despite many REDD projects having commenced since then, a standardised REDD framework is not yet in place nor operating at scale. The major roadblocks to this relate to the concepts of additionality, monitoring, reporting and verification, or MRV, and leakage. Firstly, it's important that any REDD payments are made for emissions reductions that are additional compared to businesses usual. After all, why would you pay for a forest to not be cleared if it was not going to be cleared in the first place? However, proving that a landholder would have logged a forest without receiving REDD payments is difficult. Monitoring, reporting and verification, or MRV, has also been an issue. The availability of robust data is key to ensuring REDD actually reduces carbon dioxide emissions. However, establishing how much carbon is currently stored by a forest, how much is stored annually, and how much would be released if the forest was cleared is challenging and often expensive, especially in remote areas. Data is also needed on an ongoing basis to monitor unexpected forest loss due to wildfire and illegal logging. There have also been concerns as to how carbon leakage should be addressed. That is, if logging is foregone in one location for the establishment of a REDD project, will it happen in a different location anyway? If leakage is to be avoided, REDD projects must also provide alternative and sustainable livelihood opportunities for local communities. So it's clear that significant challenges remain. Despite this, there's a concerted effort by governments and working groups to put in place a global REDD plus mechanism that plays a key role in forest conservation and reducing emissions from deforestation and degradation.