How does climate change affect river flow and impact of climate change on water resources?
Warmer temperatures increase the rate of evaporation of water into the atmosphere, in effect increasing the atmosphere's capacity to "hold" water. Increased evaporation may dry out some areas and fall as excess precipitation on other areas. Additional runoff will be compounded by lower flows and rising temperatures. More frequent droughts and shifting precipitation patterns lower water levels in rivers, lakes and streams, leaving less water to dilute pollutants. Climate change affects the social and environmental determinants of health clean air, safe drinking water, sufficient food and secure shelter. Between 2030 and 2050, climate change is expected to cause approximately 250 000 additional deaths per year, from malnutrition, malaria, diarrhoea and heat stress
We did a book covering aspects of this topic with one chapter per HKH country https://books.emeraldinsight.com/page/detail/Climate-Change-Modelling-for-Local-Adaptation-in-the-Hindu-Kush-Himalayan-Region/?K=9781780524863
This research sheds insights into the organic relationship between climate change and water resources future. Ojija, F., & Nicholaus, R. (2023). Impact of Climate Change on Water Resources and its Implications on Biodiversity: A Review. East African Journal of Environment and Natural Resources, 6(1), 15-27. Available on: Article Impact of Climate Change on Water Resources and its Implicat...
The deepening of knowledge in this field covers important issues with regard to the development of adaptation strategies that preserve water security, particularly in the arid region. The conclusion of the paper is in this respect remarkably relevant, where one may read: "Where one may read within the discussion conclusion "...There is now a fair fight between rival interpretations of the economic implications of greenhouse gas emission reductions. The use of the present tense is also more common in climate coverage, as is the presentation of language related to risk. Climate discourse is increasingly focused on the risk posed by inaction and the here and now. To the extent that citizens may not be informed of the gravity of the risk posed by uncontrolled greenhouse gas emissions, or discount threats that appear to be far in the future, these are welcome developments"
The research findings align with the holistic approach to National Water Security in water-scarce countries, which considers the comprehensive national water balances.
See also:
https://www.researchgate.net/post/Water_Footprint_Water_Colors_Blue_Water_Green_Water_Grey_Water_Virtual_Water
Progress in understanding Climate Change and its effects needs advances in modeling Climate Phenomena. "IPCC Models" "Climate Models" "General Circulation Models", appellations are of no importance. It is in all cases Physics-Driven Models developed within multi-disciplinary scientific teams worldwide to describe the evolution of weather phenomena (at short time scales) and climate phenomena that involve long time-scale processes, more complex to analyze, as part of these phenomena are not yet well understood.
This is why, despite the enormous progress already achieved, the predictability of Climate Models (The Earth System Models, ESMs), are not yet sufficiently accurate. The standard deviations between the different models remain of the same order of magnitude as the mean values and huge biases on regional levels are noticed and well documented in technical and scientific references of each of the models.
This should lead us to admit that more research is needed to improve our knowledge of the driving forces that control the climate in order to build more accurate predictive climate models, as scientists do well for weather prediction
See also:
https://www.researchgate.net/post/Climate_Change_and_Climate_Models_Progress_and_Limits
Additional runoff will be compounded by lower flows and rising temperatures. More frequent droughts and shifting precipitation patterns lower water levels in rivers, lakes and streams, leaving less water to dilute pollutants. For a start, rapid melting of glaciers will increase flow in rivers, causing floods, and as glaciers melt away, glacier fed rivers will gradually run dry. In the Indian Himalaya, small glaciers of less than 1 sq km have been retreating quickly. India is prone to droughts as well as floods even as climate change is increasing unpredictability in weather patterns and leading to more extreme weather events. Reservoirs can help mitigate these extreme events by storing water and releasing it when needed. Climate change is disrupting weather patterns, leading to extreme weather events, unpredictable water availability, exacerbating water scarcity and contaminating water supplies. Such impacts can drastically affect the quantity and quality of water that children need to survive. A warmer atmosphere can hold more moisture. In fact, for every degree of warming the atmosphere can hold around 7% more moisture. More moisture can then mean that more rainfall comes in short, intense downpours. This can increase the risk of flash flooding.Climate change can affect the intensity and frequency of precipitation. Warmer oceans increase the amount of water that evaporates into the air. When more moisture-laden air moves over land or converges into a storm system, it can produce more intense precipitation. Climate change could have significant impacts on water resources around the world because of the close connections between the climate and hydrological cycle. Rising temperatures will increase evaporation and lead to increases in precipitation, though there will be regional variations in rainfall. Climate change exacerbates water stress areas of extremely limited water resources leading to increased competition for water, even conflict. By 2040, almost 1 in 4 children will live in areas of extremely high water stress. In India, a decline in monsoon rainfall since the 1950s has already been observed. The frequency of heavy rainfall events has also increased. An abrupt change in the monsoon could precipitate a major crisis, triggering more frequent droughts as well as greater flooding in large parts of India. In addition to sea level rise, climate change is causing more floods and droughts to occur globally. As the temperature on the surface level of the Earth increases, so does the rate of evaporation. This causes the soil to dry out faster, creating harder and less permeable soil.
The effects of climate change for the next century are fairly well predicted as far as temperature is concerned. The hydrologic effects are much more uncertain. Nevertheless, the current prediction is that the temperature increase will generate a significant acceleration of the water cycle, with more evaporation. The global rainfall will thus increase, but its spatial distribution is much more uncertain.
See also: https://www.researchgate.net/publication/226652110_Changing_Water_Resources_and_Food_Supply_in_Arid_Zones_Tunisia [accessed Mar 29 2022].
Article Predictability of water resources with global climate models...
Climate change is disrupting weather patterns, leading to extreme weather events, unpredictable water availability, exacerbating water scarcity and contaminating water supplies. Such impacts can drastically affect the quantity and quality of water that children need to survive. In India, a decline in monsoon rainfall since the 1950s has already been observed. The frequency of heavy rainfall events has also increased. An abrupt change in the monsoon could precipitate a major crisis, triggering more frequent droughts as well as greater flooding in large parts of India. In addition to sea level rise, climate change is causing more floods and droughts to occur globally. As the temperature on the surface level of the Earth increases, so does the rate of evaporation. This causes the soil to dry out faster, creating harder and less permeable soil. Also droughts can alter the total amount of freshwater and cause a decline in groundwater storage, and reduction in groundwater recharge. Deterioration in water quality due to extreme events can also occur. Faster melting of glaciers can also occur.Additional runoff will be compounded by lower flows and rising temperatures. More frequent droughts and shifting precipitation patterns lower water levels in rivers, lakes and streams, leaving less water to dilute pollutants. So how is climate change affecting our rivers, and through rivers, us? For a start, rapid melting of glaciers will increase flow in rivers, causing floods, and as glaciers melt away, glacier fed rivers will gradually run dry. In the Indian Himalaya, small glaciers of less than 1 sq km have been retreating quickly. Climate change will likely lead to increases in summer temperatures, resulting in an increased demand for water resources, such as for crop irrigation. More frequent extreme low flows will impact on our water supply, water quality and the ecological health of our rivers. Lower flows, reduced velocities and, hence, higher water residence times in rivers and lakes will enhance the potential for toxic algal blooms and reduce dissolved oxygen levels.
Findings of his research [1] "Three Gorges Dam: friend or foe of riverine greenhouse gases?" put into question some prejudices and should imply further deepening of the scientific community knowledge. "These findings suggest that ‘large-dam effects’ are far beyond our previous understanding spatiotemporally, which highlights the fundamental importance of whole-system budgeting of GHGs under the profound impacts of huge dams". The question remains what comprehensive environmental impacts of such huge changes of hydrologic systems on all the components of the earth system as well as on associated modification of population activities (agriculture, industries, production...)? Then what would be the impacts of these changes on the different budgets of GHE, water cycle, and other exchanges at the interfaces of the earth system?
[1] Ni, J., Wang, H., Ma, T., Huang, R., Ciais, P., Li, Z., ... & Borthwick, A. G. (2022). Three Gorges Dam: friend or foe of riverine greenhouse gases?. National Science Review, 9(6), nwac013: Available on:
https://academic.oup.com/nsr/article-pdf/9/6/nwac013/45053354/nwac013.pdf
See also:
https://www.researchgate.net/post/Climate_Change_Water_Resources/18
The paper [1] by Besbes et al.,2023, "Predictability of water resources with global climate models. Case of Northern Tunisia" analyzes the long-term effects of climate change using the predictions from CMIP6 on Northern Tunisia’s water resources, including blue and green water. The region represents the essential source of surface water, which gives it the qualifier “water tower” of Tunisia. It is also the cereal region of the country, mainly cultivated in rain-fed: it is its “attic”. Based on hydrological modeling, the analysis aims at determining the foreseeable climate-change effect on the overall water resources of the northern region of Tunisia.
[1] Besbes, M., & Chahed, J. (2023). Predictability of water resources with global climate models. Case of Northern Tunisia. Comptes Rendus. Géoscience, 355(S1), 1-22. Available on:
Article Predictability of water resources with global climate models...
See Also:
https://www.researchgate.net/post/Climate_Change_Water_Resources
https://www.researchgate.net/post/Climate_Change_and_Climate_Models_Progress_and_Limits
The paper [1] by Peiris & Döll (released 4 days ago) "Improving the quantification of climate change hazards by hydrological models " arrives at a conclusion that deserves to be highlighted concerning the impacts of climate change on the predetermination of water resources. It says: "Application of standard equations for estimating PET in hydrological models, such as the Penman–Monteith or Priestley–Taylor-type equations, was shown to lead to an overestimation of future PET for many regions of the globe, mainly due to neglecting the impact of vegetation responses to changing atmospheric CO2 concentrations and climate. As a result, future decreases in renewable water resources may be overestimated or future increases may be underestimated. With the proposed method for PET computation in hydrological models that do not simulate vegetation processes , future PET changes occur only in response to changes in net radiation."
[1] Peiris, T.A., & Döll, P. (2023). Improving the quantification of climate change hazards by hydrological models: a simple ensemble approach for considering the uncertain effect of vegetation response to climate change on potential evapotranspiration. Hydrology and Earth System Sciences, 27(20), 3663-3686.
Available on:
https://hess.copernicus.org/articles/27/3663/2023/hess-27-3663-2023.html
See also:Article Predictability of water resources with global climate models...
Chapter: Fifty Years of Water Policies, 1960–2010. In: National Water Security. Springer, Cham, by Besbes, M., Chahed, J., Hamdane, A. (2019).
Tunisia has implemented a network of hydraulic facilities allowing to ensure safety about drinking water supply of the whole urban population and a large part, although unequally, of rural regions. Irrigation has been developed on 420,000 ha, or 8% of arable land which contribute nearly a third of the agricultural production value. The water facilities are involved, in addition, to mitigate the flood-related damage and droughts. Urban sanitation has also developed favorably in large cities, but yet very unevenly in rural areas. All these achievements have contributed to improve food and health conditions. However, this development admits an objective limit which is the threshold of exploitable resource. The policy of increasing supply of conventional resources begins to reach its limits and corollaries of accelerated water resources development were clearly identified since the early 1990s: overexploitation of many shallow and deep aquifers, water salinization in some of them, soil salinization in some irrigated areas. In this context, integrated management of the resource including demand management, is introduced to meet the growing needs expressed by various sectors. Important changes are taking place and reforms are being implemented to protect water resources, control production and use of non conventional water resources, better manage hydrological risks, anticipate conflicting sectoral interests by mobilizing all stakeholders, modernize the regulatory framework and develop appropriate plannings
Besbes, M., Chahed, J., Hamdane, A. (2019), National Water Security, Case Study of an Arid Country: Tunisia, Edition Springer. Book presentation from SpringerLink,
Book National Water Security, Case Study of an Arid Country: Tunisia
French Edition of the book: Sécurité Hydrique de la Tunisie, Gérer l'eau en conditions de pénurie. L'Harmattan, 2014, Paris.
Chapters Available on:
Chapter Sécurité Hydrique de la Tunisie : Préface & Introduction
Chapter Les Problèmes de l’Eau dans le Monde
Chapter Cinquante ans de politiques de l’eau, 1960-2010
Chapter Le Bilan Hydrique National
Chapter Le bilan Hydrique Intégral : Eau Bleue, Eau Verte et Eau Virtuelle
Chapter La gestion de la demande en eau et les ressources non conventionnelles
Chapter Sécurité Hydrique de la Tunisie, les questions en débat.
Chapter Sécurité Hydrique de la Tunisie : Conclusion & Postface
Chapter: The National Water Balance. In: National Water Security. Springer, Cham, by Besbes, M., Chahed, J., Hamdane, A. (2019).
Tunisia’s rainfall resource is 36 km3/year, generating flows for 4.8 km3/year as blue water. Groundwater withdrawals are 2 km3, and many aquifers are overexploited: the national groundwater overexploitation is 20%. The chapter presents updated information on water facilities: large dams, hill lakes and hill dams, water-table and deep aquifers, with a focus on weakly renewable resources and exploitable resources taking into account the water salinity criterion. The water resource of rainfed agriculture (green water), is 13 km3/year, increasing to 19 km3/year when including rangelands. The total blue water withdrawals are 3.0 km3, of which 0.64 km3 for municipalities and 2.2 km3 for irrigation. Coastal areas are more populated and require water from other better-endowed regions: the whole country is marked by large water transfers from West to East. The infrastructure includes comprehensive resource monitoring, in relation to groundwater whose exploitation increased 3.5 times over the past 40 years. A specific section is devoted to the anthropogenic water cycle, where a precise assessment of all water uses is provided: from withdrawals, through allocations and actual uses, to consumptive uses and returns to the receiving environment. The last part establishes the complete water balance of Tunisia, with a first prognosis of all rainfall resources processing.
Besbes, M., Chahed, J., Hamdane, A. (2019), National Water Security, Case Study of an Arid Country: Tunisia, Edition Springer. Book presentation from SpringerLink,
Book National Water Security, Case Study of an Arid Country: Tunisia
French Edition of the book: Sécurité Hydrique de la Tunisie, Gérer l'eau en conditions de pénurie. L'Harmattan, 2014, Paris.
Chapters Available on:
Chapter Sécurité Hydrique de la Tunisie : Préface & Introduction
Chapter Les Problèmes de l’Eau dans le Monde
Chapter Cinquante ans de politiques de l’eau, 1960-2010
Chapter Le Bilan Hydrique National
Chapter Le bilan Hydrique Intégral : Eau Bleue, Eau Verte et Eau Virtuelle
Chapter La gestion de la demande en eau et les ressources non conventionnelles
Chapter Sécurité Hydrique de la Tunisie, les questions en débat.
Chapter Sécurité Hydrique de la Tunisie : Conclusion & Postface
The Water Security and Sustainable Development Hub is a five-year project improving water security for a resilient future. Water security – a sustainable and adequate quantity and quality of water – is essential to human life, food and energy security, health and well-being, and economic prosperity. Yet nearly eighty percent of the world’s population live in areas where water security is thwarted by pressures such as climate change, conflict, ecosystem damage, extreme weather, gender inequalities, land degradation, over-abstraction, pollution, poor governance and uncontrolled urbanisation. The Hub brings together an international team to address these threats and contribute towards achieving the UN’s Sustainable Development Goal 6 (Clean Water and Sanitation).
See more on:
https://www.watersecurityhub.org/
Iceland volcano erupts on Reykjanes peninsula (BBC, 4 hours ago). Volcanic eruptions, always Fascinating in Beauty and Majesty, remind us in a spectacular way of essential factors in the heat balance of the globe: the transfers at the Visible Lithosphere-Atmosphere Interface in the form of Seismic and Volcanic Activities and the transfers at the Lithosphere-Hydrosphere interface, Invisible because they occur at the bottom of the oceans. Unlike the GHE, the effects of these activities on Climate Change are not well analyzed, at least in Climate Models, including those used in IPCC projections.
Illustration Source: ICELANDIC MET OFFICE:
https://www.bbc.com/news/world-europe-67756413
See Also:
https://www.researchgate.net/post/Adaptation_and_Resilience_to_Climate_Change_Temporal_Paradox_versus_Chronology_Protection_Conjecture
https://www.researchgate.net/post/Climate_Change_and_Climate_Models_Progress_and_LimitsArticle Predictability of water resources with global climate models...
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