Changes in carbon storage since the pre-industrial era: A national scale analysis

Victoria Janes-Bassett,Richard Bassett,Jessica Davies,Ed C Rowe,Edward Tipping,Dmitry Yumashev

doi:10.1016/j.ancene.2021.100289

Victoria Janes-Bassett, Richard Bassett + Show 4 more

Open Access

https://doi.org/10.1016/j.ancene.2021.100289

Copy DOI

Abstract

• N14CP model applied across the UK simulates soil and biomass C from 1700 to 2020. • N deposition increased C in natural land offsetting C loss from arable expansion. • Natural and improved grassland show increases in C whilst arable areas decrease. • Terrestrial carbon storage in the UK has increased by 6.9 % from 1700 to 2020. • Land use change is a key mechanism for C sequestration. Carbon stores in the terrestrial biosphere globally represent over 50 % of present-day organic carbon reservoirs and have significantly altered over the last three centuries owing to anthropogenic disturbances. Conversion of natural land to agricultural uses often results in a loss of soil carbon, whilst atmospheric deposition of pollutants such as nitrogen has increased carbon storage in both soil and biomass. Terrestrial carbon storage underpins a range of ecosystem services, including climate regulation, food production, and water services. This storage is crucial for sustainable land management. Quantification of terrestrial carbon cycling at regional and national scales, and understanding how human-induced drivers have impacted present-day carbon stores is therefore required to inform sustainable land use policy. This study applies the N14CP model, an integrated soil-plant biogeochemistry carbon-nitrogen-phosphorus model, across the United Kingdom to simulate changes in terrestrial carbon storage from 1700 to 2020. The analysis shows that change in anthropogenic terrestrial carbon storage is a complex picture comprising of gains in natural areas due to nitrogen deposition and afforestation, and losses in arable areas. We observed an overall net increase in total terrestrial carbon storage of 6.9 %. We note, however, that continued increases in carbon storage cannot be assumed due to (i) reduced influence of future nitrogen deposition as these systems become limited by other nutrients, (ii) the need to continue enhanced nitrogen inputs to maintain carbon sequestered, and (iii) carbon declines in arable areas continuing alongside diminishing gains in other land use types. This research provides a full picture of anthropogenic impacts on terrestrial organic carbon storage, accounting for changing nutrient cycles at a national scale.

Highlights

Carbon stored within the terrestrial biosphere plays a key role in the global carbon cycle, representing over 50 % of global organic carbon reservoirs, with relatively rapid turnover times of decades to millennia (Ciais et al, 2013)
The NATMAP carbon dataset indicated greater variability of soil carbon concentration across grid cells compared to the model output
Total topsoil organic carbon simulated by the model over the area of the dataset deviated by +12.5 %

Summary

Introduction

Carbon stored within the terrestrial biosphere plays a key role in the global carbon cycle, representing over 50 % of global organic carbon reservoirs, with relatively rapid turnover times of decades to millennia (Ciais et al, 2013). Biogeochemical cycling has significantly altered as a result of human activities due to the combined effects of land use changes and atmospheric pollution. Agricultural land use has been widely observed to deplete soil organic carbon stores as a result of decreased plant matter inputs and management practices such as tillage (Smith et al, 2016; Wei et al, 2014). As a result of these human-induced changes, the cycling and storage of terrestrial carbon has significantly altered over the last three centuries. Despite the extent of these changes, a fairly static understanding of terrestrial carbon stores exists at regional and national scales, since this knowledge is often underpinned by survey evidence that is necessarily limited in spatial resolution and in the length of time-series. Understanding how extensive humaninduced changes on Earth affect the current state of terrestrial carbon storage is limited

Methods

Results

Discussion

Conclusion