Century‐scale patterns and trends of global pyrogenic carbon emissions and fire influences on terrestrial carbon balance

Abstract

Fires have consumed a large amount of terrestrial organic carbon and significantly influenced terrestrial ecosystems and the physical climate system over the past century. Although biomass burning has been widely investigated at a global level in recent decades via satellite observations, less work has been conducted to examine the century-scale changes in global fire regimes and fire influences on the terrestrial carbon balance. In this study, we investigated global pyrogenic carbon emissions and fire influences on the terrestrial carbon fluxes from 1901 to 2010 by using a process-based land ecosystem model. Our results show a significant declining trend in global pyrogenic carbon emissions between the early 20th century and the mid-1980s but a significant upward trend between the mid-1980s and the 2000s as a result of more frequent fires in ecosystems with high carbon storage, such as peatlands and tropical forests. Over the past 110 years, average pyrogenic carbon emissions were estimated to be 2.43 Pg C yr À1 (1 Pg = 10 15 g), and global average combustion rate (defined as carbon emissions per unit area burned) was 537.85 g C m À2 burned area. Due to the impacts of fires, the net primary productivity and carbon sink of global terrestrial ecosystems were reduced by 4.14 Pg C yr À1 and 0.57 Pg C yr À1 , respectively. Our study suggests that special attention should be paid to fire activities in the peatlands and tropical forests in the future. Practical management strategies, such as minimizing forest logging and reducing the rate of cropland expansion in the humid regions, are in need to reduce fire risk and mitigate fire-induced greenhouse gases emissions.

Contributions of wildland fire to terrestrial ecosystem carbon dynamics in North America from 1990 to 2012

“…When combining the direct carbon emissions, the ecosystem recovery, with the legacy effects from historical fires, the net ecosystem carbon source was 26.09 ± 5.22 Tg C/yr during 1990–2012, which accounts for only about 5.53% of the mean annual terrestrial carbon uptake rate, indicating a small impact on the overall, long‐term net terrestrial ecosystem carbon balance in North America. Yang et al [] estimated a significantly higher fire‐caused carbon source (140 Tg C/yr) during 1900–2010 as compared to our study and several previous estimates (Table ), which was primarily due to the lack of consideration of the large fire legacy effects, which assumed no fire occurrence before 1900. This implies the importance of fire legacy effects and using the long‐term fire records in simulating ecosystem carbon dynamics.…”

“…Many studies have been conducted over the past two decades to estimate fire behavior and ecological impacts in North America based on remote sensing [e.g., Wiedinmyer and Neff , ], field observations [ French et al , ; Kasischke and Hoy , ; de Groot et al , ], and modeling simulation [e.g., Balshi et al , , ; Zhuang et al , ; Yue et al , ; Yang et al , , ]. To date, these studies have focused on (a) fire‐caused direct carbon emissions rather than net ecosystem carbon budget, (b) smaller subregions of North America rather than the continental scale, (c) use of book‐keeping approaches with fixed parameter assignments for C budget assessment, and/or (d) short‐term analyses instead of making use of the full time periods of available fire records.…”

Integrating Herbivore Population Dynamics Into a Global Land Biosphere Model: Plugging Animals Into the Earth System

“…The DLEM is driven by changes in atmospheric chemistry (i.e., nitrogen deposition, tropospheric ozone concentration, and atmospheric CO 2 concentration), climate, land‐use and land cover (LULC), and disturbances (i.e., fire and timber harvest). The model has been extensively used to quantify carbon stocks (i.e., vegetation carbon and soil carbon) and fluxes (i.e., net primary productivity and net ecosystem productivity) and the exchange of methane and nitrous oxide between multiple terrestrial ecosystems and the atmosphere (Lu & Tian ; Pan et al, ; Ren et al, ; Tian et al, ; Yang et al, ). Detailed descriptions of the processes for simulating vegetation dynamics and biogeochemical cycles are available in our previous studies (Pan et al, ; Tian et al, ).…”

The status and challenge of global fire modelling

“…Li et al (2013) also include cropland management fires, prescribing seasonal timing based on satellite observations but allowing the amount of burning to depend on the amount of post-harvest waste, population density, and gross domestic product, and fires in peatlands, depending on a prescribed area fraction of peatland distribution, climate, and area fraction of soil exposed to air. The Li et al scheme has been the basis for the fire development in the Dynamic Land Ecosystem Model (DLEM; Yang et al, 2015). A sim-ple representation of peat fires is also present in the IAP RAS CM (Eliseev et al, 2014).…”