scholarly journals Global analysis of river systems: from Earth system controls to Anthropocene syndromes

2003 ◽  
Vol 358 (1440) ◽  
pp. 1935-1955 ◽  
Author(s):  
Michel Meybeck

Continental aquatic systems from rivers to the coastal zone are considered within two perspectives: (i) as a major link between the atmosphere, pedosphere, biosphere and oceans within the Earth system with its Holocene dynamics, and (ii) as water and aquatic biota resources progressively used and transformed by humans. Human pressures have now reached a state where the continental aquatic systems can no longer be considered as being controlled by only Earth system processes, thus defining a new era, the Anthropocene. Riverine changes, now observed at the global scale, are described through a first set of syndromes (flood regulation, fragmentation, sediment imbalance, neo–arheism, salinization, chemical contamination, acidification, eutrophication and microbial contamination) with their related causes and symptoms. These syndromes have direct influences on water uses, either positive or negative. They also modify some Earth system key functions such as sediment, water, nutrient and carbon balances, greenhouse gas emissions and aquatic biodiversity. Evolution of river syndromes over the past 2000 years is complex: it depends upon the stages of regional human development and on natural conditions, as illustrated here for the chemical contamination syndrome. River damming, eutrophication and generalized decrease of river flow due to irrigation are some of the other global features of river changes. Future management of river systems should also consider these long–term impacts on the Earth system.

Science ◽  
2021 ◽  
Vol 373 (6550) ◽  
pp. 51-55
Author(s):  
Aron Stubbins ◽  
Kara Lavender Law ◽  
Samuel E. Muñoz ◽  
Thomas S. Bianchi ◽  
Lixin Zhu

Plastic contamination of the environment is a global problem whose magnitude justifies the consideration of plastics as emergent geomaterials with chemistries not previously seen in Earth’s history. At the elemental level, plastics are predominantly carbon. The comparison of plastic stocks and fluxes to those of carbon reveals that the quantities of plastics present in some ecosystems rival the quantity of natural organic carbon and suggests that geochemists should now consider plastics in their analyses. Acknowledging plastics as geomaterials and adopting geochemical insights and methods can expedite our understanding of plastics in the Earth system. Plastics also can be used as global-scale tracers to advance Earth system science.


Author(s):  
Tim Lenton

Could the Earth system be on the brink of another revolutionary change, thanks to human activities? We humans are very recent products of evolution, yet already we are transforming the planet at a global scale. The recognition that humans are now a key component of the Earth system was encapsulated in the Bretherton diagram. More recently, the term ‘Anthropocene’ has been coined to describe a new geological epoch in which human activities are transforming the Earth system at a global scale. ‘Anthropocene’ introduces how human evolution was shaped by changes in the Earth system and how we have gone on to transform the Earth system—tracing the key events on a timeline.


2021 ◽  
Vol 13 (15) ◽  
pp. 8161
Author(s):  
Nick King ◽  
Aled Jones

Human civilisation has undergone a continuous trajectory of rising sociopolitical complexity since its inception; a trend which has undergone a dramatic recent acceleration. This phenomenon has resulted in increasingly severe perturbation of the Earth System, manifesting recently as global-scale effects such as climate change. These effects create an increased risk of a global ‘de-complexification’ (collapse) event in which complexity could undergo widespread reversal. ‘Nodes of persisting complexity’ are geographical locations which may experience lesser effects from ‘de-complexification’ due to having ‘favourable starting conditions’ that may allow the retention of a degree of complexity. A shortlist of nations (New Zealand, Iceland, the United Kingdom, Australia and Ireland) were identified and qualitatively analysed in detail to ascertain their potential to form ‘nodes of persisting complexity’ (New Zealand is identified as having the greatest potential). The analysis outputs are applied to identify insights for enhancing resilience to ‘de-complexification’.


2020 ◽  
Vol 3 (1) ◽  
Author(s):  
Dantong Liu ◽  
Cenlin He ◽  
Joshua P. Schwarz ◽  
Xuan Wang

Abstract Light-absorbing carbonaceous aerosols (LACs), including black carbon and light-absorbing organic carbon (brown carbon, BrC), have an important role in the Earth system via heating the atmosphere, dimming the surface, modifying the dynamics, reducing snow/ice albedo, and exerting positive radiative forcing. The lifecycle of LACs, from emission to atmospheric evolution further to deposition, is key to their overall climate impacts and uncertainties in determining their hygroscopic and optical properties, atmospheric burden, interactions with clouds, and deposition on the snowpack. At present, direct observations constraining some key processes during the lifecycle of LACs (e.g., interactions between LACs and hydrometeors) are rather limited. Large inconsistencies between directly measured LAC properties and those used for model evaluations also exist. Modern models are starting to incorporate detailed aerosol microphysics to evaluate transformation rates of water solubility, chemical composition, optical properties, and phases of LACs, which have shown improved model performance. However, process-level understanding and modeling are still poor particularly for BrC, and yet to be sufficiently assessed due to lack of global-scale direct measurements. Appropriate treatments of size- and composition-resolved processes that influence both LAC microphysics and aerosol–cloud interactions are expected to advance the quantification of aerosol light absorption and climate impacts in the Earth system. This review summarizes recent advances and up-to-date knowledge on key processes during the lifecycle of LACs, highlighting the essential issues where measurements and modeling need improvement.


Daedalus ◽  
2015 ◽  
Vol 144 (3) ◽  
pp. 94-109 ◽  
Author(s):  
Charles J. Vörösmarty ◽  
Michel Meybeck ◽  
Christopher L. Pastore

Water is an essential building block of the Earth system and a nonsubstitutable resource upon which humankind must depend. But a growing body of evidence shows that freshwater faces a pandemic array of challenges. Today we can observe a globally significant but collectively unorganized approach to addressing them. Under modern water management schemes, impairment accumulates with increasing wealth but is then remedied by costly, after-the-fact technological investments. This strategy of treating symptoms rather than underlying causes is practiced widely across rich countries but leaves poor nations and many of the world's freshwater life-forms at risk. The seeds of this modern “impair-then-repair” mentality for water management were planted long ago, yet the wisdom of our “water traditions” may be ill-suited to an increasingly crowded planet. Focusing on rivers, which collectively satisfy the bulk of the world's freshwater needs, this essay explores the past, present, and possible future of human-water interactions. We conclude by presenting the impair-then-repair paradigm as a testable, global-scale hypothesis with the aim of stimulating not only systematic study of the impairment process but also the search for innovative solutions. Such an endeavor must unite and cobalance perspectives from the natural sciences and the humanities.


PAGES news ◽  
2010 ◽  
Vol 18 (2) ◽  
pp. 55-57 ◽  
Author(s):  
Cathy Whitlock ◽  
Willy Tinner
Keyword(s):  

2017 ◽  
Author(s):  
Caroline A. Masiello ◽  
◽  
Jonathan J. Silberg ◽  
Hsiao-Ying Cheng ◽  
Ilenne Del Valle ◽  
...  

2021 ◽  
Vol 13 (9) ◽  
pp. 1716
Author(s):  
Ankur Srivastava ◽  
Jose F. Rodriguez ◽  
Patricia M. Saco ◽  
Nikul Kumari ◽  
Omer Yetemen

Atmospheric transmissivity (τ) is a critical factor in climatology, which affects surface energy balance, measured at a limited number of meteorological stations worldwide. With the limited availability of meteorological datasets in remote areas across different climatic regions, estimation of τ is becoming a challenging task for adequate hydrological, climatic, and crop modeling studies. The availability of solar radiation data is comparatively less accessible on a global scale than the temperature and precipitation datasets, which makes it necessary to develop methods to estimate τ. Most of the previous studies provided region specific datasets of τ, which usually provide local assessments. Hence, there is a necessity to give the empirical models for τ estimation on a global scale that can be easily assessed. This study presents the analysis of the τ relationship with varying geographic features and climatic factors like latitude, aridity index, cloud cover, precipitation, temperature, diurnal temperature range, and elevation. In addition to these factors, the applicability of these relationships was evaluated for different climate types. Thus, empirical models have been proposed for each climate type to estimate τ by using the most effective factors such as cloud cover and aridity index. The cloud cover is an important yet often overlooked factor that can be used to determine the global atmospheric transmissivity. The empirical relationship and statistical indicator provided the best performance in equatorial climates as the coefficient of determination (r2) was 0.88 relatively higher than the warm temperate (r2 = 0.74) and arid regions (r2 = 0.46). According to the results, it is believed that the analysis presented in this work is applicable for estimating the τ in different ecosystems across the globe.


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