Contribution of forcings to Holocene climate evolution

2021 ◽  
Author(s):  
Peter Hopcroft ◽  
Paul Valdes
Keyword(s):  
Land Use ◽  
Land Use Change ◽  
General Circulation ◽  
Volcanic Eruptions ◽  
Reconstruction Method ◽  
Major Advance ◽  
Model Ensemble ◽  
The Holocene ◽  
The Past ◽  
Climate Evolution

<p>The climate evolution of the past few thousand years is essential for understanding the context in which civilisation arose and for understanding the natural background of anthropogenic influence. Proxy-inferred records show a complex picture of earlier warming and later cooling during the Holocene depending on region and reconstruction method. In contrast climate model simulations almost uniformly show warming throughout the past 10,000 years and for example also fail to reproduce a major advance of rainbelt over the Sahara.  These discrepancies raise questions about the reliability of climate models on longer-time scales.</p><p>We present a suite of four new transient Holocene simulations covering the last 8500 years using the HadCM3B-M21aD coupled general circulation. We use an optimised version of this model which is able to replicate the greening of the Sahara through changes to the atmospheric convection and vegetation schemes. We apply transient changes in Earth’s orbit, ice-sheets and sea-level and greenhouse gases, and optionally solar output, volcanic eruptions and anthropogenic land-use change.  The simulations without land-use show a warming throughout the Holocene, albeit with significantly higher variability once volcanic eruptions are included. With the inclusion of land-use change temperature trends in Northern Hemisphere are reversed from around 4000 years before present.</p><p>We explore the contribution of different forcings to the regional trends in the model ensemble and we compare the simulations against the Holocene reconstructions to evaluate the relative importance of each forcing. We also use the model ensemble to quantify the terrestrial coverage of proxy locations that is required to reliably infer global mean temperature variations.</p>

THE AFFECT OF LAND USE CHANGE ON STABLE ISOTOPE (δ13C AND δ15N) VALUES IN CONNECTICUT WETLANDS DURING THE HOLOCENE

2016 ◽  
Author(s):  
Caitlin T. McManimon ◽  
◽  
David P. Gillikin ◽  
William B. Ouimet ◽  
Michael T. Hren ◽  
...  
Keyword(s):  
Land Use ◽  
Stable Isotope ◽  
Land Use Change ◽  
Δ13c And Δ15n ◽  
The Holocene

scholarly journals Estimating historical land use patterns in Amazonia for hydrological studies

2017 ◽  
Vol 8 (4) ◽  
pp. 189-197
Author(s):  
Christiane Cavalcante Leite ◽  
Marcos Heil Costa ◽  
Ranieri Carlos Ferreira de Amorim
Keyword(s):  
Land Use ◽  
Water Resources ◽  
Land Use Change ◽  
Census Data ◽  
Land Use Patterns ◽  
Use Patterns ◽  
The Past ◽  
The World ◽  
Historical Land Use ◽  
Past Land Use

The evaluation of the impacts of land-use change on the water resources has been, many times, limited by the knowledge of past land use conditions. Most publications on this field present only a vague description of the past land use, which is usually insufficient for more comprehensive studies. This study presents the first reconstruction of the historical land use patterns in Amazonia, that includes both croplands and pasturelands, for the period 1940-1995. During this period, Amazonia experienced the fastest rates of land use change in the world, growing 4-fold from 193,269 km2 in 1940 to 724,899 km2 in 1995. This reconstruction is based on a merging of satellite imagery and census data, and provides a 5'x5' yearly dataset of land use in three different categories (cropland, natural pastureland and planted pastureland) for Amazonia. This dataset will be an important step towards understanding the impacts of changes in land use on the water resources in Amazonia.

scholarly journals The past, present and future impacts of climate and land use change on snowshoe hares along their southern range boundary

2020 ◽  
Vol 249 ◽  
pp. 108731
Author(s):  
Evan C. Wilson ◽  
Benjamin Zuckerberg ◽  
M. Zachariah Peery ◽  
Jonathan N. Pauli
Keyword(s):  
Land Use ◽  
Land Use Change ◽  
Range Boundary ◽  
The Past ◽  
Snowshoe Hares

scholarly journals Potential Changes of Annual-Averaged Nutrient Export in the South Saskatchewan River Basin under Climate and Land-Use Change Scenarios

Water ◽  
2018 ◽  
Vol 10 (10) ◽  
pp. 1438 ◽  
Author(s):  
Luis Morales-Marín ◽  
Howard Wheater ◽  
Karl-Erich Lindenschmidt
Keyword(s):  
Water Quality ◽  
Land Use ◽  
Land Use Change ◽  
General Circulation ◽  
Large Scale ◽  
Land Use Changes ◽  
General Circulation Models ◽  
Nutrient Export ◽  
The South ◽  
South Saskatchewan River

Climate and land-use changes modify the physical functioning of river basins and, in particular, influence the transport of nutrients from land to water. In large-scale basins, where a variety of climates, topographies, soil types and land uses co-exist to form a highly heterogeneous environment, a more complex nutrient dynamic is imposed by climate and land-use changes. This is the case of the South Saskatchewan River (SSR) that, along with the North Saskatchewan River, forms one of the largest river systems in western Canada. The SPAtially Referenced Regression On Watershed (SPARROW) model is therefore implemented to assess water quality in the basin, in order to describe spatial and temporal patterns and identify those factors and processes that affect water quality. Forty-five climate and land-use change scenarios comprehended by five General Circulation Models (GCMs) and three Representative Concentration Pathways (RCPs) were incorporated into the model to explain how total nitrogen (TN) and total phosphorus (TP) export could vary across the basin in 30, 60 and 90 years from now. According to model results, annual averages of TN and TP export in the SSR are going to increase in the range 0.9–1.28 kg km − 2 year − 1 and 0.12–0.17 kg km − 2 year − 1 , respectively, by the end of the century, due to climate and land-use changes. Higher increases of TP compared to TN are expected since TP and TN are going to increase ∼36% and ∼21%, respectively, by the end of the century. This research will support management plans in order to mitigate nutrient export under future changes of climate and land use.

scholarly journals Land Use Projections Under Alternative Policies: A Transition Matrix Approach

1979 ◽  
Vol 8 (2) ◽  
pp. 87-99 ◽  
Author(s):  
Bruce E. Lindsay ◽  
Daniel L. Dunn
Keyword(s):  
Land Use ◽  
Land Use Change ◽  
Land Use Planning ◽  
Current Trend ◽  
Land Use Policy ◽  
Decision Makers ◽  
Policy Makers ◽  
The Past ◽  
Accelerated Growth ◽  
Insight Into

As a result of accelerated growth during the past decade, land use change over time and its accompanying problems represents a policy area germane to New Hampshire. Accurate projections of the future pattern of land use would be helpful to decision makers responsible for land use policy. Such projections could assist policy makers either directly in formulating land use plans or indirectly in justifying the need (or lack of need) for overt land use planning. Future projections, based upon various alternative land use policy scenarios, will increase the quantitative supply of information to decision makers in a two-fold manner. First, such estimates provide an insight into the current trend in land use mix and, secondly, give an overview of what impacts various policies directly have upon land use change.

Agricultural land use change and associated driving forces over the past 180 years in two municipalities of the Brazilian Cerrado

GeoJournal ◽  
2018 ◽  
Vol 84 (3) ◽  
pp. 555-570 ◽  
Author(s):  
Murilo Rodrigues de Arruda ◽  
Maja Slingerland ◽  
José Zilton Lopes Santos ◽  
Ken E. Giller
Keyword(s):  
Land Use ◽  
Land Use Change ◽  
Agricultural Land ◽  
Driving Forces ◽  
Agricultural Land Use ◽  
Brazilian Cerrado ◽  
The Past

scholarly journals The changing face of southern New Zealand farming: opportunities of land use change

2012 ◽  
pp. 1-6
Author(s):  
R.J. Copland ◽  
D.R. Stevens
Keyword(s):  
Land Use ◽  
New Zealand ◽  
Land Use Change ◽  
Dairy Cows ◽  
Social Influences ◽  
Family Ownership ◽  
Marginal Land ◽  
Dairy Sheep ◽  
The Past ◽  
Potential Land

Southern New Zealand has seen major changes in land use in the past 20 years with the rise in dairy cows in milk from 149 000 in 1994 to 682 000 in 2010, while breeding ewe numbers have declined from 11.2 million to 7.3 million over the same period. The development of milking platforms with a significant need for winter dairy grazing has opened up many opportunities for sheep, beef and deer farmers in the region. The need to remain profitable, displacement of sheep to more marginal land, and social influences such as retaining family ownership have encouraged farmers to make the most of potential land-use change opportunities. Three case studies outline the changes made and potential profitability increases in dairy conversion, flexible sheep and beef operations and improved deer production, with cash surplus after expenses being more than doubled in each case. Keywords: land use, profit, dairy, sheep, beef, deer.

scholarly journals The impact of nitrogen and phosphorous limitation on the estimated terrestrial carbon balance and warming of land use change over the last 156 yr

2013 ◽  
Vol 4 (1) ◽  
pp. 507-539 ◽  
Author(s):  
Q. Zhang ◽  
A. J. Pitman ◽  
Y. P. Wang ◽  
Y. Dai ◽  
P. J. Lawrence
Keyword(s):  
Land Use ◽  
Land Use Change ◽  
Nutrient Limitation ◽  
Co2 Emissions ◽  
Carbon Sink ◽  
Terrestrial Carbon ◽  
The Past ◽  
The Difference ◽  
Terrestrial Carbon Sink ◽  
The Impact

Abstract. We examine the impact of land use and land cover change (LULCC) over the period from 1850 to 2005 using an Earth System Model that incorporates nitrogen and phosphorous limitation on the terrestrial carbon cycle. We compare the estimated CO2 emissions and warming from land use change in a carbon only version of the model with those from simulations including nitrogen and phosphorous limitation. If we omit nutrients, our results suggest LULCC cools on the global average by about 0.1 °C. Including nutrients reduces this cooling to ~ 0.05 °C. Our results also suggest LULCC has a major impact on total land carbon over the period 1850–2005. In carbon only simulations, the inclusion of LULCC decreases the total additional land carbon stored in 2005 from around 210 Pg C to 85 Pg C. Including nitrogen and phosphorous limitation also decreases the scale of the terrestrial carbon sink to 80 Pg C. In particular, adding LULCC on top of the nutrient limited simulations changes the sign of the terrestrial carbon flux from a sink to a source (12 Pg C). The CO2 emission from LULCC from 1850 to 2005 is estimated to be 130 Pg C for carbon only simulation, or 97 Pg C if nutrient limitation is accounted for in our model. The difference between these two estimates of CO2 emissions from LULCC largely results from the weaker response of photosynthesis to increased CO2 and smaller carbon pool sizes, and therefore lower carbon loss from plant and wood product carbon pools under nutrient limitation. We suggest that nutrient limitation should be accounted in simulating the effects of LULCC on the past climate and on the past and future carbon budget.

Sign in / Sign up

Export Citation Format

Share Document