Forcings and feedbacks by land ecosystem changes on climate change

Betts, Richard

doi:10.1051/jp4:2006139009

Cited by 20 publications

(16 citation statements)

References 3 publications

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“…Moreover, background tree mortality rates have doubled over recent decades across western NA, an increase that has been attributed to elevated temperatures (van Mantgem et al 2009). Such a widespread vegetation change over western NA has important implications for ecosystem services and feedbacks between regional-scale vegetation change, carbon storage, and climate Kurz et al 2008a,b;Betts 2006;Bonan 2008;Running 2008;Peñ uelas et al 2009;Adams et al 2010;Michaelian et al 2011). The conversion of forests from carbon sinks to sources may influence governmental decisions regarding forest management and greenhouse gas emissions policies (Kurz et al 2008a;Allison et al 2009).…”

Section: Introductionmentioning

confidence: 96%

Projected Future Changes in Vegetation in Western North America in the Twenty-First Century

et al. 2013

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Rapid and broad-scale forest mortality associated with recent droughts, rising temperature, and insect outbreaks has been observed over western North America (NA). Climate models project additional future warming and increasing drought and water stress for this region. To assess future potential changes in vegetation distributions in western NA, the Community Earth System Model (CESM) coupled with its Dynamic Global Vegetation Model (DGVM) was used under the future A2 emissions scenario. To better span uncertainties in future climate, eight sea surface temperature (SST) projections provided by phase 3 of the Coupled Model Intercomparison Project (CMIP3) were employed as boundary conditions. There is a broad consensus among the simulations, despite differences in the simulated climate trajectories across the ensemble, that about half of the needleleaf evergreen tree coverage (from 24% to 11%) will disappear, coincident with a 14% (from 11% to 25%) increase in shrubs and grasses by the end of the twenty-first century in western NA, with most of the change occurring over the latter half of the twenty-first century. The net impact is a ;6 GtC or about 50% decrease in projected ecosystem carbon storage in this region. The findings suggest a potential for a widespread shift from tree-dominated landscapes to shrub and grass-dominated landscapes in western NA because of future warming and consequent increases in water deficits. These results highlight the need for improved process-based understanding of vegetation dynamics, particularly including mortality and the subsequent incorporation of these mechanisms into earth system models to better quantify the vulnerability of western NA forests under climate change.

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Section: Introductionmentioning

confidence: 96%

Projected Future Changes in Vegetation in Western North America in the Twenty-First Century

et al. 2013

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“…Many ecosystem processes are directly or indirectly climate driven, and together with anthropogenic land cover changes (ALCCs), they determine how the land surface will evolve over time (Betts, 2006;Brovkin et al, 2006;Claussen et al, 2001). The climate system is influenced in a biophysical manner by affecting radiative forcing through a changing albedo or heat fluxes (Matthews et al, 2003;Myhre and Myhre, 2003;Davin et al, 2007) but also through biogeochemical processes by exchanging greenhouse gases (GHGs) and other gases with the atmosphere (Betts, 2006;Brovkin et al, 2006;Betts et al, 2007). All these feedbacks on land use can be either positive or negative (Claussen et al, 2001).…”

Section: Introductionmentioning

confidence: 99%

Anthropogenic land use estimates for the Holocene – HYDE 3.2

Goldewijk

Beusen

Doelman

et al. 2017

Earth Syst. Sci. Data

761

624

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Abstract. This paper presents an update and extension of HYDE, the History Database of the Global Environment (HYDE version 3.2). HYDE is an internally consistent combination of historical population estimates and allocation algorithms with time-dependent weighting maps for land use. Categories include cropland, with new distinctions for irrigated and rain-fed crops (other than rice) and irrigated and rain-fed rice. Grazing lands are also provided, divided into more intensively used pasture and less intensively used rangeland, and further specified with respect to conversion of natural vegetation to facilitate global change modellers. Population is represented by maps of total, urban, rural population, population density and built-up area. The period covered is 10 000 before Common Era (BCE) to 2015 Common Era (CE). All data can be downloaded from https://doi.org/10.17026/dans-25g-gez3.We estimate that global population increased from 4.4 million people (we also estimate a lower range < 0.01 and an upper range of 8.9 million) in 10 000 BCE to 7.257 billion in 2015 CE, resulting in a global population density increase from 0.03 persons (or capita, in short cap) km −2 (range 0-0.07) to almost 56 cap km −2 respectively. The urban built-up area evolved from almost zero to roughly 58 Mha in 2015 CE, still only less than 0.5 % of the total land surface of the globe.Cropland occupied approximately less than 1 % of the global land area (13 037 Mha, excluding Antarctica) for a long time period until 1 CE, quite similar to the grazing land area. In the following centuries the share of global cropland slowly grew to 2.2 % in 1700 CE (ca. 293 Mha, uncertainty range 220-367 Mha), 4.4 % in 1850 CE (578 Mha, range 522-637 Mha) and 12.2 % in 2015 CE (ca. 1591 Mha, range 1572-1604 Mha). Cropland can be further divided into rain-fed and irrigated land, and these categories can be further separated into rice and non-rice. Rain-fed croplands were much more common, with 2.2 % in 1700 CE (289 Mha, range 217-361 Mha), 4.2 % (549 Mha, range 496-606 Mha) in 1850 CE and 10.1 % (1316 Mha, range 1298-1325 Mha) in 2015 CE, while irrigated croplands used less than 0.05 % (4.3 Mha, range 3.1-5.5 Mha), 0.2 % (28 Mha, range 25-31 Mha) and 2.1 % (277 Mha, range 273-278 Mha) in 1700, 1850 and 2015 CE, respectively. We estimate the irrigated rice area (paddy) to be 0.1 % (13 Mha, range 9-16 Mha) in 1700 CE, 0.2 % (28 Mha, range 26-31 Mha) in 1850 CE and 0.9 % (118 Mha, range 117-120 Mha) in 2015 CE.The estimates for land used for grazing are much more uncertain. We estimate that the share of grazing land grew from 5.1 % in 1700 CE (667 Mha, range 507-820 Mha) to 9.6 % in 1850 CE (1192 Mha, range 1068-1304 Mha) and 24.9 % in 2015 CE (3241 Mha, range 3211-3270 Mha). To aid the modelling community we have divided land used for grazing into more intensively used pasture, less intensively used converted rangeland and less or unmanaged natural unconverted rangeland. Pasture occupied 1.1 % in 1700 CE (145 Mha, range 79-175 Mha), 1.9 % in 1850 CE (253 Mha...

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“…In 2006, the third year after the fire, the LAI starts to increase, indicating vegetation regrowth on the surface. In 2006, the LAI values over burned area are comparable to those in unburned area, but they are generally lower.…”

Section: Discussionmentioning

confidence: 60%

“…White-sky albedos behave similarly to black-sky albedos and are not shown separately here. NIR albedo over a burned area decreases substantially in 2004 and 2005 and starts to increase in late summer of 2005 and in the year of 2006, 2008, and 2009, the burned area has a higher albedo compared to the unburned buffer area. This finding is consistent with studies mentioned previously (e.g., Amiro et al 1999).…”

Section: Discussionmentioning

confidence: 95%

Satellite-Observed Surface Temperature Changes after the 2004 Taylor Complex Fire in Alaska

2011

Earth Interactions

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Land-use and land-cover change has been recognized as a key component in global climate change. In the boreal forest ecosystem, fires often cause significant changes in vegetation structure and surface biophysical characteristics, which in turn dramatically change energy and water balances of land surface. Several studies have characterized fire-induced changes in surface energy balance in boreal ecosystem based on site observations. This study provides satellite-observed impacts of a large fire on surface climate in Alaska's boreal forest. A land surface temperature (LST) product from NASA's Moderate Resolution Imaging Spectroradiometer (MODIS) is used as the primary data. Five years after fire, surface temperature over the burned area increased by an average of 2.08C in the May-August period. The increase reached a maximum of 3.28C in the year immediately following the fire. The warm anomaly decreased slightly after the second year but remained until the fifth year of the study. These changes in surface temperature may directly affect surface net radiation and thus partition of surface available energy. By documenting continuous and synoptic surface temperature changes over multiple years, this paper demonstrates the value of Earth Observing System (EOS) observations for landclimate interaction research. The observed characteristics of surface temperature change as well as changes in key surface biophysical parameters such as albedo and leaf area index (LAI) can be used in the next generation of climate models to improve the representation of large-scale ecosystem disturbances.

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Forcings and feedbacks by land ecosystem changes on climate change

Cited by 20 publications

References 3 publications

Projected Future Changes in Vegetation in Western North America in the Twenty-First Century

Projected Future Changes in Vegetation in Western North America in the Twenty-First Century

Anthropogenic land use estimates for the Holocene – HYDE 3.2

Satellite-Observed Surface Temperature Changes after the 2004 Taylor Complex Fire in Alaska

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