Forestry based solutions, including forest restoration and avoided deforestation and degradation are vital for climate change mitigation and adaption. Thus methods to quantify changes in above-ground biomass (AGB), in the form of emissions from forest degradation and removals from forest restoration are vital. Radar data has been widely used to map and quantify changes in AGB, however mapping these subtle changes in AGB over time is challenging. Here I discuss the use of L-band Radar data in mapping AGB change, highlighting the advantages and disadvantages. I will also discuss new opportunities for AGB mapping from new spaceborne sensors, detailing some of the methods we will be testing in the 4C project.