We disagree strongly with the suggestion by Jim Lynch and colleagues that the outputs of the Global Observation of Forest and Land Cover Dynamics panel and the Global Forest Observations Initiative “lack ambition and an understanding of the potential of satellites” (Nature 496, 293–294; 2013).

As participants in these programmes and in the United Nations Programme on Reducing Emissions from Deforestation and Forest Degradation (UN-REDD), we aim to show how remote sensing can help systematic global monitoring to make REDD+ a reality in the context of wider societal engagement. (REDD+ is a climate-mitigation initiative under the UN Framework Convention on Climate Change (UNFCCC).)

We also question the feasibility of Lynch and colleagues' call for rapid-response satellite monitoring of deforestation to be enshrined in international law under the UNFCCC, given national sovereignty concerns and the fact that we are not yet in a position to mitigate the problems of cloud cover. Although radar can penetrate cloud, the technology cannot yet capture changes in forest ecosystems in a systematic and repeatable way.