Xinghua Cheng explains how medium spatial resolution satellite observations, such as Landsat and Sentinel-2, are used to estimate and forecast crop yields over large scales.
Biochar soil application has been widely promoted as an option for carbon dioxide removal; however, its effects on crop productivity remain uncertain. In this Review, we synthesize evidence from global field experiments to identify the key drivers of biochar-promoted crop productivity change. Biochar increased crop productivity by an average of 12.8% globally, with the productivity of tap-root crops (32%) being substantially greater than staple cereals with fibrous-root systems (8%). Productivity increases are generally application-rate-dependent and are most pronounced in warm, acid, clay-rich soils. Biochar enhances crop productivity through nutrient enhancement and soil conditioning effects. Biochar improves soil structure, water retention and biological functioning via its porous architecture and reactive surfaces. Although productivity benefits decline over time, the positive effects can persist for more than 3 years after application. As biochar ages, interactions between clay minerals and organic matter further enhance soil aggregation, resource retention and acquisition and crop tolerance to drought and salinity. Future research should examine biochar-mediated resilience across diverse soil–crop systems and expand field testing to under-represented crops and regions to guide the effective deployment of biochar for sustainable food production. Improving crop production is essential to meet the rising food demand of the increasing global population. This Review synthesizes global evidence that biochar enhances crop productivity, explores the underlying mechanisms and considers how biochar can contribute to sustainable food production.
The blue carbon capacity of mangroves is an important contributor to climate change mitigation. Southeast Asia holds one-third of the world’s mangroves, although these ecosystems have previously experienced substantial loss and degradation, with large areas now available for restoration. We describe the distribution of mangrove carbon across Southeast Asia and the threats mangroves face, estimate their climate change mitigation potential, and synthesize progress and challenges in using mangroves as a regional natural climate solution. Mangrove conservation in Southeast Asia can avoid 13.53 Tg CO2e per year of emissions from land use change and sequester 0.96 Tg CO2e per year through restoration. Progress is being made in the implementation of blue carbon projects, with most countries incorporating mangroves into National Greenhouse Gas Inventories and Paris Agreement targets, and multiple commercial carbon credit schemes registered or under evaluation. However, socio-economic and governance constraints limit mangrove blue carbon strategies, potentially allowing only 5.5–34.2% of biophysically suitable restoration to be realized. Constraints include national and local enabling conditions, double counting of carbon for national and commercial offsetting, ambiguity in land tenure and carbon rights, financial barriers and capacity gaps. Overall, the mangroves of Southeast Asia have the potential to contribute to climate change mitigation, but substantial constraints to their conservation and restoration must first be overcome. This Review examines the climate change mitigation potential of mangroves in Southeast Asia. The authors quantify emissions avoidance and restoration benefits, and discuss the socio-economic, governance and financial barriers that constrain large-scale implementation of mangrove-based blue carbon conservation and restoration.
