Abstract
The global temperature could increase over 1.5 or even 2 °C by the middle of 21st century due to massive emissions of greenhouse gases (GHGs) — of which carbon dioxide (CO2) is the largest component1. Human activities emit more than 10 PgC (1PgC=1015gC) per year into the atmosphere1, which is regarded as the primary reason for increased atmospheric CO2 concentration and global warming2. Global vegetation sequesters 112–169 PgC each year3, about half of which is released back into the atmosphere through autotrophic respiration while the rest, termed as net primary production (NPP), is for balancing the CO2 emissions from human activities, microbial respiration, and decomposition4. Carbon sequestration from vegetation varies under different environmental conditions5 and could also be significantly altered by land management practices (LMPs)6. Adopting optimal land management practices (OLMPs) helps sequester more CO2 from the atmosphere and mitigate climate changes. Understanding the extra carbon sequestration with OLMPs, or termed as carbon gap, is an important scientific topic that is rarely studied. Here we propose an integrated method to identify the location-specific OLMPs and assess the carbon gap by using remotely sensed time-series of NPP dataset, segmented landscape-vegetation-soil (LVS) zones and distance-constrained zonal analysis. The findings show that the carbon gap from global land plants totaled 13.74 PgC per year with OLMPs referenced from within a 20km neighborhood, an equivalent of ~1/5 of the total sequestered net carbon at the current level; half of the carbon gap clusters in only ~15% of vegetated area. The carbon gap flux rises with population density and the priority for implementing OLMPs should be given to the densely populated areas to enhance the global carbon sequestration capacity.
Carbon stewardship: land management decisions and the potential for carbon sequestration in Colorado, USA
