Link between black carbon, fires, climate change, and human activity during the Holocene period shown in the loess-paleosol sequence from Henan, China

2017 ◽  
Vol 87 (2) ◽  
pp. 288-297
Author(s):  
Yan Mu ◽  
Xiaoguang Qin ◽  
Lei Zhang ◽  
Bing Xu

AbstractHenan was the site of development for several ancient cultures during the Holocene. In this study, black carbon (BC) in the Holocene sediment is compared with known climatic changes and cultural events to provide information concerning the link between fire, climatic changes, and human activity in Xiangcheng. Prior to 8000 cal yr BP, the occurrence of fires was low under cold and dry climatic conditions. The BC content in 8000–1000calyrBP indicates a gradual increase in fire, with two peak values at 7500calyrBP and 3500 cal yr BP. The first peak correlates to the development of the Peiligang culture, and the second peak correlates to the development of wet and warm climate conditions along with the appearance of the Xia–Shang dynasties. Increases in fire activity could therefore be attributed to climate change and the development of human civilization in the region. Another sharp increase in fires around 1000calyrBP was consistent with a sharp increase in population during the Tang dynasty.

2019 ◽  
Vol 22 (1) ◽  
pp. 343-360 ◽  
Author(s):  
Vally Koubi

The link between climate change and conflict has been discussed intensively in academic literature during the past decade. This review aims to provide a clearer picture of what the research community currently has to say with regard to this nexus. It finds that the literature has not detected a robust and general effect linking climate to conflict onset. Substantial agreement exists that climatic changes contribute to conflict under some conditions and through certain pathways. In particular, the literature shows that climatic conditions breed conflict in fertile grounds: in regions dependent on agriculture and in combination and interaction with other socioeconomic and political factors such as a low level of economic development and political marginalization. Future research should continue to investigate how climatic changes interact with and/or are conditioned by socioeconomic, political, and demographic settings to cause conflict and uncover the causal mechanisms that link these two phenomena.


2021 ◽  
pp. 145-156
Author(s):  
Manzoor Hussain ◽  
Ljupcho Jankuloski ◽  
M. Habib-ur-Rahman ◽  
Massoud Malek ◽  
Md. Kamrul Islam ◽  
...  

Abstract Cotton, being a leading commercial fibre crop, is grown on 20.5 million hectares in three major cotton-producing countries: China, India and Pakistan. Wide differences in yield per hectare exist among these countries and these are being aggravated by changing climate conditions, i.e. higher temperatures and significant seasonal and regional fluctuation in rainfall. Pakistan is one of the countries most affected by climate change. The disastrous effects of extreme periods of heat stress in cotton were very prominent in Pakistan during the growing seasons 2013-2014 (40-50% fruit abortion) and 2016-2017 (33% shortfall), which posed an alarming threat to the cotton-based economy of Pakistan. Poor resilience of the most commonly grown cotton varieties against extreme periods of heat stress are considered to be major factors for this drastic downfall in cotton production in Pakistan. Using the approach of induced mutation breeding, the Nuclear Institute for Agriculture and Biology (NIAB), Faisalabad, Pakistan, has demonstrated its capabilities in developing cotton mutants that can tolerate the changed climatic conditions and sustain high yields under contrasting environments. The results of studies on the phenological and physiological traits conferring heat tolerance are presented here for thermo-tolerant cotton mutants (NIAB-878, NIAB-545, NIAB-1048, NIAB-444, NIAB-1089, NIAB-1064, NIAB-1042) relative to FH-142 and FH-Lalazar. NIAB-878 excelled in heat tolerance by maintaining the highest anther dehiscence (82%) and minimum cell injury percentage (39%) along with maximum stomatal conductance (27.7 mmol CO2/m2/s), transpiration rate (6.89 μmol H2O/m2/s), net photosynthetic rate (44.6 mmol CO2/m2/s) and physiological water use efficiency (6.81 mmol CO2/μmol H2O) under the prevailing high temperatures.


2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Dan-Dan Yu ◽  
Shan Li ◽  
Zhong-Yang Guo

The evaluation of climate comfort for tourism can provide information for tourists selecting destinations and tourism operators. Understanding how climate conditions for tourism evolve is increasingly important for strategic tourism planning, particularly in rapidly developing tourism markets like China in a changing climate. Multidimensional climate indices are needed to evaluate climate for tourism, and previous studies in China have used the much criticized “climate index” with low resolution climate data. This study uses the Holiday Climate Index (HCI) and daily data from 775 weather stations to examine interregional differences in the tourist climate comfortable period (TCCP) across China and summarizes the spatiotemporal evolution of TCCP from 1981 to 2010 in a changing climate. Overall, most areas in China have an “excellent” climate for tourism, such that tourists may visit anytime with many choices available. The TCCP in most regions shows an increasing trend, and China benefits more from positive effects of climate change in climatic conditions for tourism, especially in spring and autumn. These results can provide some scientific evidence for understanding human settlement environmental constructions and further contribute in improving local or regional resilience responding to global climate change.


2020 ◽  
Author(s):  
Sabrina Prochazka ◽  
Marta Luciani ◽  
Christopher Lüthgens

<p>The arid regions of the world occupy 46% of the total surface area, providing a habitat for 3 billion people. More than 630 million people are directly affected by desertification. Extreme events like droughts and flash floods increase the pressure on plants, animals and above all, humans and their settlements. In the context of a climate change with such far-reaching consequences, historical oases settlements stand out as best practice examples, because their water supply systems must have been adapted to the changing climate during the Holocene to guarantee the viability of the oases and their inhabitants. I will focus on the ancient oasis Qurayyah, located in the northwest of the Arabian Peninsula, a unique example in this context. Recent research has proven that, lacking a groundwater spring, the formation of a permanent settlement in Qurayyah was made possible mainly by surface-water harvesting, with local fracture springs potentially only providing drinking water. First numerical dating results for the water harvesting system from optically stimulated luminescence (OSL) dating of quartz confirm that the system was erected in a period characterized by changing climatic conditions from the Holocene climate optimum to the recent arid phase. This study aims to determine parameters and chronology of this sustainable irrigation system and intends to learn and understand how ancient settlers accomplished the construction of such a highly developed water supply system. To reach this research aim the irrigation system was reconstructed using field mapping and remote sensing techniques. It was shown that the reconstructed irrigation system worked as a flood irrigation system. Dams and channels were built to maximize the flooded area and at the same time to prevent catastrophic flooding under high discharge conditions. Contemporaneous historical irrigation systems in comparable size and complexity are known from Mesopotamia or Egypt. In addition to the system’s reconstruction, a new reverse engineering approach based on palaeobotany was developed for Qurayyah to reconstruct the climate conditions during the time of its operation. Compared to today’s precipitation of 32 mm per year in the research area, our results imply that the irrigation system was constructed in a time of significant climate change, because significantly higher amounts of precipitation would have been necessary to enable the cultivation of olive trees (reference plant for the reverse engineering approach), with a sufficient amount of water.</p>


2020 ◽  
Author(s):  
Matti Kummu ◽  
Matias Heino ◽  
Maija Taka ◽  
Olli Varis ◽  
Daniel Viviroli

<p>The majority of global food production, as we know it, is based on agricultural practices developed within stable Holocene climate conditions. Climate change is altering the key conditions for human societies, such as precipitation, temperature and aridity. Their combined impact on altering the conditions in areas where people live and grow food has not yet, however, been systematically quantified on a global scale. Here, we estimate the impacts of two climate change scenarios (RCP 2.6, RCP 8.5) on major population centres and food crop production areas at 5 arc-min scale (~10 km at equator) using Holdridge Life Zones (HLZs), a concept that incorporates all the aforementioned climatic characteristics. We found that if rapid growth of GHG emissions is not halted (RCP 8.5), in year 2070, one fifth of the major food production areas and one fourth of the global population centres would experience climate conditions beyond the ones where food is currently produced, and people are living. Our results thus reinforce the importance of following the RCP 2.6 path, as then only a small fraction of food production (5%) and population centres (6%) would face such unprecedented conditions. Several areas experiencing these unprecedented conditions also have low resilience, such as those within Burkina Faso, Cambodia, Chad, and Guinea-Bissau. In these countries over 75% of food production and population would experience unprecedented climatic conditions under RCP 8.5. These and many other hotspot areas require the most urgent attention to secure sustainable development and equity.</p>


2015 ◽  
Vol 61 (4) ◽  
pp. 669-689 ◽  
Author(s):  
Pamela D. Noyes ◽  
Sean C. Lema

Abstract Global climate change is impacting organisms, biological communities and ecosystems around the world. While most research has focused on characterizing how the climate is changing, including modeling future climatic conditions and predicting the impacts of these conditions on biodiversity, it is also the case that climate change is altering the environmental impacts of chemical pollution. Future climate conditions are expected to influence both the worldwide distribution of chemicals and the toxicological consequences of chemical exposures to organisms. Many of the environmental changes associated with a warming global climate (e.g., increased average – and possibly extreme – temperatures; intense periods of drier and wetter conditions; reduced ocean pH; altered salinity dynamics in estuaries) have the potential to enhance organism susceptibility to chemical toxicity. Additionally, chemical exposures themselves may impair the ability of organisms to cope with the changing environmental conditions of the shifting climate. Such reciprocity in the interactions between climate change and chemicals illustrates the complexity inherent in predicting the toxicological consequences of chemical exposures under future climate scenarios. Here, we summarize what is currently known about the potential reciprocal effects of climate change and chemical toxicity on wildlife, and depict current approaches and ongoing challenges for incorporating climate effects into chemical testing and assessment. Given the rapid pace of new man-made chemistries, the development of accurate and rapid methods to evaluate multiple chemical and non-chemical stressors in an ecologically relevant context will be critical to understanding toxic and endocrine-disrupting effects of chemical pollutants under future climate scenarios.


2011 ◽  
Vol 8 (5) ◽  
pp. 8793-8830 ◽  
Author(s):  
M. Renner ◽  
R. Seppelt ◽  
C. Bernhofer

Abstract. Long term average change in streamflow is a major concern in hydrology and water resources management. Some simple analytical methods exist for the assessment of the sensitivity of streamflow to climatic variations. These are based on the Budyko hypothesis, which assumes that long term average streamflow can be predicted by climate conditions, namely by annual average precipitation and evaporative demand. Recently, Tomer and Schilling (2009) presented an ecohydrological concept to distinguish between effects of climate change and basin characteristics change on streamflow. We provide a theoretical foundation of this concept by showing that it is based on a coupled consideration of the water and energy balance. The concept uses a special condition that the sum of the ratio of annual actual evapotranspiration to precipitation and the ratio of actual to potential evapotranspiration is constant, even when climate conditions are changing. Here we apply this assumption and derive analytical solutions to the problem of streamflow sensitivity on climate. We show how climate sensitivity is influenced by different climatic conditions and the actual hydrological response of a basin. Finally, the properties and implications of the new method are compared with established Budyko sensitivity methods.


Author(s):  
Abha Laddha

Global climatic changes because of human activities have become a major threat to life on Earth. Changing climatic conditions are the result of man-made activities and are continuously leading to a serious deterioration in the earth’s atmosphere. Basically it is leading to erratic climate and weather extremes, altered ecosystems and habitats and risks to human health and society. This problem can be solved only if some judicious steps are taken, including improvements to energy efficiency and vehicle fuel economy, increases in wind and solar power, hydrogen produced from renewable sources, biofuels (produced from crops), natural gas, and nuclear power.


Forests ◽  
2020 ◽  
Vol 11 (6) ◽  
pp. 684
Author(s):  
Yang Liu ◽  
Juan Shi

Climate change is predicted to alter the geographic distribution of a wide variety of taxa, including insects. Icerya aegyptiaca (Douglas) and I. purchasi Maskell are two polyphagous and invasive pests in the genus Icerya Signoret (Hemiptera: Monophlebidae) and cause serious damage to many landscape and economic trees. However, the global habitats suitable for these two Icerya species are unclear. The purpose of this study is to determine the potentially suitable habitats of these two species, then to provide scientific management strategies. Using MaxEnt software, the potential risk maps of I. aegyptiaca and I. purchasi were created based on their occurrence data under different climatic conditions and topology factors. The results suggested that under current climate conditions, the potentially habitable area of I. aegyptiaca would be much larger than the current distribution and there would be small changes for I. purchasi. In the future climate change scenarios, the suitable habitats of these two insect species will display an increasing trend. Africa, South America and Asia would be more suitable for I. aegyptiaca. South America, Asia and Europe would be more suitable for I. purchasi. Moreover, most of the highly habitat suitability areas of I. aegyptiaca will become concentrated in Southern Asia. The results also suggested that “min temperature of coldest month” was the most important environmental factor affecting the prediction models of these two insects. This research provides a theoretical reference framework for developing policies to manage and control these two invasive pests of the genus Icerya.


2021 ◽  
Author(s):  
Matti Kummu ◽  
Matias Heino ◽  
Maija Taka ◽  
Olli Varis ◽  
Daniel Viviroli

<p>The majority of food production is based on agricultural practices developed for the stable Holocene climatic conditions, which now are under risk for rapid change due to climate change. Although various studies have assessed the potential changes in climatic conditions and their projected impacts on yields globally, there is no clear understanding on the climatic niche of the current food production. Nor, which areas are under risk of falling outside this niche.</p><p>In this study we aim first at defining the novel concept Safe Climatic Space (SCS) by using a combination of three key climatic parameters. SCS is defined here as the climate conditions to which current food production systems (here crop production and livestock production separately) are accustomed to, an analogue to Safe Operating Space (SOS) concepts such as Planetary Boundaries and human climate niche. We use a combination of selected key climatic factors to define the SCS through the Holdridge Life Zone (HLZ) concept. It allows us to first define the SCS based on three climatic factors (annual precipitation, biotemperature and aridity) and to identify which food production areas would stay within it under changed future climate conditions. </p><p>We show that a rapid and unhalted growth of GHG emissions (SSP5-8.5) could force 31% (25-37% with 5th-95th percentile confidence interval) of global food crop production and 34% (26-43%) of livestock production beyond the SCS by 2081-2100. Our results underpin the importance of committing to a low emission scenario (SSP1-2.6), whereupon the extent of food production facing unprecedented conditions would be a fraction: 8% (4-10%) for crop production and 4% (2-8%) for livestock production. The most vulnerable areas are the ones at risk of leaving SCS with low resilience to cope with the change, particularly South and Southeast Asia and Africa’s Sudano-Sahelian Zone. </p><p>Our findings reinforce the existing research in suggesting that climate change forces humanity into a new era of reduced validity of past experiences and dramatically increased uncertainties. Future solutions should be concentrated on actions that would both mitigate climate change as well as increase resilience in food systems and societies, increase the food production sustainability that respects key planetary boundaries, adapt to climate change by, for example, crop migration and foster local livelihoods especially in the most critical areas.</p>


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