Browsing by Author "Porkka, Miina"

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Archetypal flow regime change classes and their associations with anthropogenic drivers of global streamflow alterations
(2024-11-01) Virkki, Vili; Sahu, Reetik Kumar; Smilovic, Mikhail; Láng-Ritter, Josias; Porkka, Miina; Kummu, Matti
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Streamflow—a key component of the water cycle—is experiencing drastic alteration due to human actions. The global extent and degree of this change have been widely assessed, but understanding of its drivers remains limited because previous global-scale approaches have largely relied on modelled hypothetical scenarios. Here, we advance this understanding by providing an observation-based association analysis of streamflow change and its drivers. We use observed streamflow data in 3,293 catchments globally and combine them with data on precipitation, evapotranspiration, water use, and damming. Building on a robust annual trend analysis covering years 1971-2010, we first determine flow regime change (FRC) classes, and then use them to investigate associations between streamflow change and its drivers. We find that 91% of all catchments are assigned to four main FRCs, which indicates globally consistent flow regime changes. By associating driver trends with the FRCs, we further characterise them by trends and changes in the four investigated drivers. We find that FRCs depicting decreasing streamflow quantity and variability are strongly associated with direct human drivers, either water use or damming. In contrast, associations with indirect drivers (precipitation and evapotranspiration) are more dominant in FRCs that depict increasing streamflow quantity and variability. Our key advance is that our comprehensive, observation-based association analysis substantiates the model-based findings of previous global-scale studies, and thus adds detail and validation to their interpretations. This may further support developing and adopting efficient measures to mitigate streamflow change and its subsequent impacts across scales.
Bringing it all together : linking measures to secure nations’ food supply
(2017-12-01) Kummu, Matti; Fader, Marianela; Gerten, Dieter; Guillaume, Joseph HA; Jalava, Mika; Jägermeyr, Jonas; Pfister, Stephan; Porkka, Miina; Siebert, Stefan; Varis, Olli
A2 Katsausartikkeli tieteellisessä aikakauslehdessä
A growing human population and changing consumption patterns threaten adequate food supply globally by increasing pressure on already scarce land and water resources. Various measures have been suggested to sustainably secure future food supply: diet change, food loss reduction and closing the yield gap of nutrients as well as water. As yet, they have been assessed separately or, if combined, at a global or macro-region level only. In this paper, we carry out a review and integration of this literature to provide a first estimate of the combined potential of these measures at country level. The overall potential increase in global food supply was estimated to be 111% and 223% at moderate and high implementation levels, respectively. Projected global food demand in 2050 could thus be met, but deficiencies in various countries in Africa and the Middle East appear inevitable without changes to trade or adapting with future innovations. Further, this analysis highlights country-level management opportunities for each intervention studied. Several potential future research opportunities are proposed to improve integration of measures.
Can we cut the water footprint of Finland by changing diet?
(2015-09-21) Ahlström, Annica
Insinööritieteiden korkeakoulu | Master's thesis
Previous studies have shown that a diet change and waste reduction have shown possibilities in reducing water consumption. By using the available resources sustainably it can result in reduced water scarcity and deliver improved food security. In this study I aim to assess how a diet change would impact on Finnish water use for food production. First the water consumption of the current Finnish diet is calculated. Then the diet was adjusted to correspond with the dietary recommendation. Thereafter, the amount of animal products is gradually reduced in three steps, 50%, 25% and 0%. In addition to this, the water footprint of two specific diets, Pale and Mediterranean is calculated. The blue water footprint increased by 3 – 23% for the animal protein scenarios compared to the recommended diet while the green water decreased by 4 – 22%. The water footprint of Paleo diet increased by a remarkable 67% and 56% for the blue and green water footprint respectively. The Mediterranean diet resulted in a high blue water foot-print (58% increase) while the green water footprint is similar to that of the current diet. The results of this study shows that changes in diets can have a clear impact on the water consumption of producing food. Studying the water consumption on a country level with local recommendations gives a deeper insight into how the diets affect the water footprints. Finland is a country with high consumption of animal products and a high daily energy intake, reducing the energy intake and amount of animal products can decrease the water footprint of a diet in Finland.
Causes and trends of water scarcity in food production
(2016-01) Porkka, Miina; Gerten, Dieter; Schaphoff, Sibyll; Siebert, Stefan; Kummu, Matti
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
The insufficiency of water resources to meet the needs of food production is a pressing issue that is likely to increase in importance in the future. Improved understanding of historical developments can provide a basis for addressing future challenges. In this study we analyse how hydroclimatic variation, cropland expansion and evolving agricultural practices have influenced the potential for food self-sufficiency within the last century. We consider a food production unit (FPU) to have experienced green-blue water (GBW) scarcity if local renewable green (in soils) and blue water resources (in rivers, lakes, reservoirs, aquifers) were not sufficient for producing a reference food supply of 3000 kcal with 20% animal products for all inhabitants. The number of people living in FPUs affected by GBW scarcity has gone up from 360 million in 1905 (21% of world population at the time) to 2.2 billion (34%) in 2005. During this time, GBW scarcity has spread to large areas and become more frequent in regions where it occurs. Meanwhile, cropland expansion has increased green water availability for agriculture around the world, and advancements in agronomic practices have decreased water requirements of producing food. These efforts have improved food production potential and thus eased GBW scarcity considerably but also made possible the rapid population growth of the last century. The influence of modern agronomic practices is particularly striking: if agronomic practices of the early 1900s were applied today, it would roughly double the population under GBW scarcity worldwide.
Diet change - a solution to reduce water use ?
(2014) Jalava, Mika; Kummu, Matti; Porkka, Miina; Siebert, Stefan; Varis, Olli
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Water and land resources are under increasing pressure in many parts of the globe. Diet change has been suggested as a measure to contribute to adequate food security for the growing population. This paper assesses the impact of diet change on the blue and green water footprints of food consumption. We first compare the water consumption of the current diets with that of a scenario where dietary guidelines are followed. Then, we assess these footprints by applying four scenarios in which we gradually limit the amount of protein from animal products to 50%, 25%, 12.5% and finally 0% of the total protein intake. We find that the current water use at the global scale would be sufficient to secure a recommended diet and worldwide energy intake. Reducing the animal product contribution in the diet would decrease global green water consumption by 6%, 11%, 15% and 21% within the four applied scenarios, while for blue water, the reductions would be 4%, 6%, 9% and 14%. In Latin America, Europe, Central and Eastern Asia and Sub-Saharan Africa, diet change mainly reduces green water use, while in the Middle East region, North America, Australia and Oceania, both blue and green water footprints decrease considerably. At the same time, in South and Southeast Asia, diet change does not result in decreased water use. Our results show that reducing animal products in the human diet offers the potential to save water resources, up to the amount currently required to feed 1.8 billion additional people globally; however, our results show that the adjustments should be considered on a local level.
Diet change and food loss reduction: What is their combined impact on global water use and scarcity?
(2016-03) Jalava, Mika; Guillaume, Joseph H. A.; Kummu, Matti; Porkka, Miina; Siebert, Stefan; Varis, Olli
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
There is a pressing need to improve food security and reduce environmental impacts of agricultural production globally. Two of the proposed measures are diet change from animal-based to plant-based foodstuffs and reduction of food losses and waste. These two measures are linked, as diet change affects production and consumption of foodstuffs and consequently loss processes through their different water footprints and loss percentages. This paper takes this link into account for the first time and provides an assessment of the combined potential contribution of diet change and food loss reduction for reducing water footprints and water scarcity. We apply scenarios in which we change diets to follow basic dietary recommendations, limit animal-based protein intake to 25% of total protein intake, and halve food losses to study single and combined effects of diet change and loss reduction. Dietary recommendations alone would achieve 6% and 7% reductions of blue and green water consumption, respectively, while changing diets to contain less animal products would result in savings of 11% and 18%, respectively. Halving food loss would alone achieve 12% reductions for both blue and green water. Combining the measures would reduce water consumption by 23% and 28%, respectively, lowering water scarcity in areas with a population of over 600 million. At a global scale, effects of diet change and loss reduction were synergistic with loss reductions being more effective under changed diet. This demonstrates the importance of considering the link between diet change and loss reduction in assessments of food security and resource use.
Distance and diversity: Exploring the minimum distances to fulfil current food supply diversity
(2023-03-20) Saukkonen, Sara
Insinööritieteiden korkeakoulu | Master's thesis
Diversity of food supply is essential to both human nutrition and resilience of food systems. Globalisation of food systems and trading has led to increases in food security and food supply diversity. However, trade dependency can also lead to vulnerability, such as vulnerability to market shocks. This issue has given rise to local food discourse and assessments, but they have been more focused on sufficiency of calorific or nutrient production while diversity of food has gained less attention. This thesis highlights the aspect of the missing diversity and aims to find country-specific minimum distances to similar diet as their current food supply both in terms of calories and diversity. The analysis expands food production areas from each country one country at a time to find a production area which meets both the calorific and diversity conditions set by the origin country’s food supply. While 50% of world population in 2013 lived in countries where the local production was self-sufficient in terms of calories, only 5.5% lived in countries where the same was true for diversity. While calorific self-sufficiency is more common and diversity requirement leads to expansion of food production areas, all countries find a food production area with similar diversity but the same is not true for calories. In fact, the calorie condition is more restrictive for finding a food production area with similar diet when both conditions must be met at the same time. In 2013, 37% of the world population lived in countries whose diets could not be sustained with global food production if everyone in the world were to eat as them when both calories and diversity is considered. Of the remaining countries, 50% have a distance to similar diet of 2600 km or less and for 75%, the distance is 4500 km or less. The share of the world population in countries where a distance to similar diet was found has increased from 53% in 1995 to 63% in 2013. While more people are living in countries where a distance to similar diets is found, the distances have increased. The results highlight the impact that globalisation and trading have had on the food supply diversity where increases have been achieved more with trade instead of increases in local food production diversity. Diversity of food supply and local production are important elements when researching the level of localness in food systems.
Earth beyond six of nine planetary boundaries
(2023-09-15) Richardson, Katherine; Steffen, Will; Lucht, Wolfgang; Bendtsen, Jørgen; Cornell, Sarah E.; Donges, Jonathan F.; Drüke, Markus; Fetzer, Ingo; Bala, Govindasamy; von Bloh, Werner; Feulner, Georg; Fiedler, Stephanie; Gerten, Dieter; Gleeson, Tom; Hofmann, Matthias; Huiskamp, Willem; Kummu, Matti; Mohan, Chinchu; Nogués-Bravo, David; Petri, Stefan; Porkka, Miina; Rahmstorf, Stefan; Schaphoff, Sibyll; Thonicke, Kirsten; Tobian, Arne; Virkki, Vili; Wang-Erlandsson, Lan; Weber, Lisa; Rockström, Johan
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
This planetary boundaries framework update finds that six of the nine boundaries are transgressed, suggesting that Earth is now well outside of the safe operating space for humanity. Ocean acidification is close to being breached, while aerosol loading regionally exceeds the boundary. Stratospheric ozone levels have slightly recovered. The transgression level has increased for all boundaries earlier identified as overstepped. As primary production drives Earth system biosphere functions, human appropriation of net primary production is proposed as a control variable for functional biosphere integrity. This boundary is also transgressed. Earth system modeling of different levels of the transgression of the climate and land system change boundaries illustrates that these anthropogenic impacts on Earth system must be considered in a systemic context.
Exploring the Modifiable Areal Unit Problem in Spatial Water Assessments: A Case of Water Shortage in Monsoon Asia
(2015) Salmivaara, Aura; Porkka, Miina; Kummu, Matti; Keskinen, Marko; Guillaume, Joseph H.A.; Varis, Olli
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Water shortage (availability per capita) is a key indicator of vulnerability to water scarcity. Spatial datasets enable the assessment of water shortage on multiple scales. The use of river basins and subbasins as analysis and management units is currently commonplace. An important but less acknowledged fact is that spatial assessments are strongly influenced by the choice of the unit of analysis due to the Modifiable Areal Unit Problem (MAUP). Climate conditions, agricultural activities, and access to groundwater also influence water availability and demand. In this study, a total of 21 different criteria were used to define areal units of analysis, i.e., zonings, for which water shortage was calculated. Focusing on Monsoon Asia, where water scarcity is a pressing problem, we found that zoning had a considerable impact, resulting in up to three-fold differences in the population under high water shortage (<1000 m3/cap/year), ranging from 782 million to 2.11 billion. In most zonings, however, the Indus and Yellow River Basins and northwest parts of India and China are under high water shortage. The study indicates that a multizonal and multiscale analysis is needed to minimize skewed or even misleading information that might be produced when using only one zoning.
From food insufficiency towards trade dependency: a historical analysis of global food availability
(2013) Porkka, Miina; Kummu, Matti; Siebert, Stefan; Varis, Olli
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Achieving global food security is one of the major challenges of the coming decades. In order to tackle future food security challenges we must understand the past. This study presents a historical analysis of global food availability, one of the key elements of food security. By calculating national level dietary energy supply and production for nine time steps during 1965–2005 we classify countries based on their food availability, food self-sufficiency and food trade. We also look at how diets have changed during this period with regard to supply of animal based calories. Our results show that food availability has increased substantially both in absolute and relative terms. The percentage of population living in countries with sufficient food supply (>2500 kcal/cap/d) has almost doubled from 33% in 1965 to 61% in 2005. The population living with critically low food supply (<2000 kcal/cap/d) has dropped from 52% to 3%. Largest improvements are seen in the MENA region, Latin America, China and Southeast Asia. Besides, the composition of diets has changed considerably within the study period: the world population living with high supply of animal source food (>15% of dietary energy supply) increased from 33% to over 50%. While food supply has increased globally, food self-sufficiency (domestic production>2500 kcal/cap/d) has not changed remarkably. In the beginning of the study period insufficient domestic production meant insufficient food supply, but in recent years the deficit has been increasingly compensated by rising food imports. This highlights the growing importance of food trade, either for food supply in importing countries or as a source of income for exporters. Our results provide a basis for understanding past global food system dynamics which, in turn, can benefit research on future food security.
Future trends in freshwater planetary boundary transgressions
(2023-06-12) Mäkelä, Juho
Insinööritieteiden korkeakoulu | Master's thesis
Changes in the global freshwater cycle have become increasingly common around the world since mankind’s industrialization. The concept of planetary boundaries (PBs) is a framework defining safe limits for human activity in terms of changes in Earth subsystems, freshwater being one of the boundaries. Here the goal was to use the recently proposed new method for the freshwater change PB to determine the status of and changes in it during this century under two climate change scenarios (RCP2.6 and RCP6.0). Additionally, local changes were determined to identify areas where freshwater changes are likely to cause potential risks, especially to the agricultural sector. The impact of climate change was assessed by comparing the two chosen scenarios. Data from ISIMIP2b was used to determine global and local changes in discharge and root-zone soil moisture. Changes were calculated as the frequency of monthly discharge or root-zone soil moisture values exiting variability based on pre-industrial conditions on each 0.5-degree grid cell. Each grid cell has its local variability bounds calculated from preindustrial data (1691-1860), with values below 5th percentile being considered a dry exit, and values above 95th percentile being wet exits. Additionally, dry exit frequency values were used in conjunction with crop yield and land-use data to determine risk to the agricultural sector by calculating a risk index. The freshwater change planetary boundary has already been transgressed, and the trend continues upward in the future, especially in the higher-emissions RCP6.0 climate scenario where the share of global land area where discharge or root-zone soil moisture exits preindustrial variability bounds keeps rising through-out the century. In RCP2.6 this trend stabilizes around the 2050s. Discharge changes have fewer differences between climate scenarios than root-zone soil moisture. Notable regions with a high dry exit frequency include the Mediterranean, China, and India, while Canada, Russia, Northern Europe, and India have a high wet exit frequency. The agricultural sectors of some of the largest global crop producers are at risk in the future due to drying conditions, including the North American Corn Belt, Western Europe, Northern China, and India. Mitigating climate change to reduce water cycle changes, as well as sustainable irrigation practices to cope with decreasing water resources, are key to ensuring continued food and water supply for humanity. The results of the thesis are valuable, as they help in identifying the potential areas where adaptation to change is most critical.
Giving legs to handprint thinking : foundations for evaluating the good we do
(2020-06-01) Guillaume, Joseph H. A.; Sojamo, Suvi; Porkka, Miina; Gerten, Dieter; Jalava, Mika; Lankoski, Leena; Lehikoinen, Elina; Lettenmeier, Michael; Pfister, Stephan; Usva, Kirsi; Wada, Yoshihide; Kummu, Matti
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
In environmental management and sustainability there is an increasing interest in measurement and accounting of beneficial impact-as an incentive to action, as a communication tool, and to move toward a positive, constructive approach focused on opportunities rather than problems. One approach uses the metaphor of a "handprint," complementing the notion of environmental footprints, which have been widely adopted for impact measurement and accounting. We analyze this idea by establishing core principles of handprint thinking: Handprint encourages actions with positive impacts and connects to analyses of footprint reductions but adds value to them and addresses the issue of what action should be taken. We also identify five key questions that need to be addressed and decisions that need to be made in performing a (potentially quantitative) handprint assessment, related to scoping of the improvement to be made, how it is achieved, and how credit is assigned, taking into account constraints on action. A case study of the potential water footprint reduction of an average Finn demonstrates how handprint thinking can be a natural extension of footprint reduction analyses. We find that there is a diversity of possible handprint assessments that have the potential to encourage doing good. Their common foundation is "handprint thinking."
A global analysis of potential self-sufficiency and diversity displays diverse supply risks
(2023-06) Wassénius, Emmy; Porkka, Miina; Nyström, Magnus; Søgaard Jørgensen, Peter
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
International trade plays a fundamental role in today's globalized food system, however, trade-related disruptions to national food supply have become increasingly prevalent. Although national food self-sufficiency and the resilience of domestic food production are both increasingly discussed, they are rarely investigated in tandem. This hinders our understanding of the diversity of risks to national food supply. In this article we investigate the contribution of production to these risks, through the compilation of a comprehensive national production dataset and a multi-indicator assessment of self-sufficiency and diversity. Our results show that most of the world (127 countries and territories, 87% of the global population) achieves high levels of potential self-sufficiency (≥6 nutrients fulfilled), however only 33% of the world population (41 countries) are fully self-sufficient. Of countries with high levels of self-sufficiency, fruit and vegetable production (a proxy for many micronutrients) is the most common “missing” sufficiency. 66 countries (6% of population) have a low degree of self-sufficiency, highlighting potential vulnerability to trade-related disruptions. The relationship between sufficiency and diversity is not homogeneous, highlighting that some production systems are reliant on very few products.
Globally widespread and increasing violations of environmental flow envelopes
(2022-07-01) Virkki, Vili; Alanärä, Elina; Porkka, Miina; Ahopelto, Lauri; Gleeson, Tom; Mohan, Chinchu; Wang-Erlandsson, Lan; Flörke, Martina; Gerten, Dieter; Gosling, Simon N.; Hanasaki, Naota; Müller Schmied, Hannes; Wanders, Niko; Kummu, Matti
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Human actions and climate change have drastically altered river flows across the world, resulting in adverse effects on riverine ecosystems. Environmental flows (EFs) have emerged as a prominent tool for safeguarding the riverine ecosystems, but at the global scale, the assessment of EFs is associated with high uncertainty related to the hydrological data and EF methods employed. Here, we present a novel, in-depth global EF assessment using environmental flow envelopes (EFEs). Sub-basin-specific EFEs are determined for approximately 4400 sub-basins at a monthly time resolution, and their derivation considers the methodological uncertainties related to global-scale EF studies. In addition to a lower bound of discharge based on existing EF methods, we introduce an upper bound of discharge in the EFE. This upper bound enables areas to be identified where streamflow has substantially increased above natural levels. Further, instead of only showing whether EFs are violated over a time period, we quantify, for the first time, the frequency, severity, and trends of EFE violations during the recent historical period. Discharge was derived from global hydrological model outputs from the ISIMIP 2b ensemble. We use pre-industrial (1801-1860) quasi-natural discharge together with a suite of hydrological EF methods to estimate the EFEs. We then compare the EFEs with recent historical (1976-2005) discharge to assess the violations of the EFE. These violations most commonly manifest as insufficient streamflow during the low-flow season, with fewer violations during the intermediate-flow season, and only a few violations during the high-flow season. The EFE violations are widespread and occur in half of the sub-basins of the world during more than 5% of the months between 1976 and 2005, which is double compared with the pre-industrial period. The trends in EFE violations have mainly been increasing, which will likely continue in the future with the projected hydroclimatic changes and increases in anthropogenic water use. Indications of increased upper extreme streamflow through EFE upper bound violations are relatively scarce and dispersed. Although local fine-tuning is necessary for practical applications, and further research on the coupling between quantitative discharge and riverine ecosystem responses at the global scale is required, the EFEs provide a quick and globally robust way of determining environmental flow allocations at the sub-basin scale to inform global research and policies on water resources management.
Illuminating water cycle modifications and Earth system resilience in the Anthropocene
(2020-04-01) Gleeson, Tom; Wang‐Erlandsson, Lan; Porkka, Miina; Zipper, Samuel C.; Jaramillo, Fernando; Gerten, Dieter; Fetzer, Ingo; Cornell, Sarah E.; Piemontese, Luigi; Gordon, Line J.; Rockström, Johan; Oki, Taikan; Sivapalan, Murugesu; Wada, Yoshihide; Brauman, Kate A.; Flörke, Martina; Bierkens, Marc F. P.; Lehner, Bernhard; Keys, Patrick; Kummu, Matti; Wagener, Thorsten; Dadson, Simon; Troy, Tara J.; Steffen, Will; Falkenmark, Malin; Famiglietti, James S.
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Fresh water—the bloodstream of the biosphere—is at the center of the planetary drama of the Anthropocene. Water fluxes and stores regulate the Earth's climate and are essential for thriving aquatic and terrestrial ecosystems, as well as water, food, and energy security. But the water cycle is also being modified by humans at an unprecedented scale and rate. A holistic understanding of freshwater's role for Earth system resilience and the detection and monitoring of anthropogenic water cycle modifications across scales is urgent, yet existing methods and frameworks are not well suited for this. In this paper we highlight four core Earth system functions of water (hydroclimatic regulation, hydroecological regulation, storage, and transport) and key related processes. Building on systems and resilience theory, we review the evidence of regional-scale regime shifts and disruptions of the Earth system functions of water. We then propose a framework for detecting, monitoring, and establishing safe limits to water cycle modifications and identify four possible spatially explicit methods for their quantification. In sum, this paper presents an ambitious scientific and policy grand challenge that could substantially improve our understanding of the role of water in the Earth system and cross-scale management of water cycle modifications that would be a complementary approach to existing water management tools.
Integrating the Water Planetary Boundary With Water Management From Local to Global Scales
(2020-02) Zipper, Samuel C.; Jaramillo, Fernando; Wang-Erlandsson, Lan; Cornell, Sarah E.; Gleeson, Tom; Porkka, Miina; Häyhä, Tiina; Crepin, Anne-Sophie; Fetzer, Ingo; Gerten, Dieter; Hoff, Holger; Matthews, Nathanial; Ricaurte-Villota, Constanza; Kummu, Matti; Wada, Yoshihide; Gordon, Line
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
The planetary boundaries framework defines the "safe operating space for humanity" represented by nine global processes that can destabilize the Earth System if perturbed. The water planetary boundary attempts to provide a global limit to anthropogenic water cycle modifications, but it has been challenging to translate and apply it to the regional and local scales at which water problems and management typically occur. We develop a cross-scale approach by which the water planetary boundary could guide sustainable water management and governance at subglobal contexts defined by physical features (e.g., watershed or aquifer), political borders (e.g., city, nation, or group of nations), or commercial entities (e.g., corporation, trade group, or financial institution). The application of the water planetary boundary at these subglobal contexts occurs via two approaches: (i) calculating fair shares, in which local water cycle modifications are compared to that context's allocation of the global safe operating space, taking into account biophysical, socioeconomic, and ethical considerations; and (ii) defining a local safe operating space, in which interactions between water stores and Earth System components are used to define local boundaries required for sustaining the local water system in stable conditions, which we demonstrate with a case study of the Cienaga Grande de Santa Marta wetlands in Colombia. By harmonizing these two approaches, the water planetary boundary can ensure that water cycle modifications remain within both local and global boundaries and complement existing water management and governance approaches.
Interplay of trade and food system resilience : Gains on supply diversity over time at the cost of trade independency
(2020-03-01) Kummu, Matti; Kinnunen, Pekka; Lehikoinen, Elina; Porkka, Miina; Queiroz, Cibele; Röös, Elin; Troell, Max; Weil, Charlotte
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Rapidly increasing international food trade has drastically altered the global food system over the past decades. Using national scale indicators, we assess two of the resilience principles that directly reflect the effects of global trade on food systems – namely, maintaining diversity and redundancy, and managing connectivity. We perform our analysis for four nutritional components: dietary energy, proteins, fat, and quantity of vegetables & pizza – the key pillars of the WHO dietary recommendations. Our results indicate that, between 1987 and 2013, food supply diversity increased significantly for most of the world's population at the cost of an elevated dependency upon food imports. Food production diversity, particularly in terms of dietary energy and vegetables & pizza, increased for a large proportion of the world population, with the exception being major exporting countries, where it decreased. Of particular note is our finding that, despite a growing number of people being heavily dependent upon imports, the number of import partners decreased more often than it increased, except for the case of vegetables & pizza. This combination of increased dependency on imports and a reduced number of import partners indicates a potential vulnerability to disruptions in linked food systems. Additionally, it is alarming that we found many countries where the studied resilience aspects systematically declined, elevating their exposure to future shocks in the food system.
Is wetter better? Exploring agriculturally-relevant rainfall characteristics over four decades in the Sahel
(2021-03) Porkka, Miina; Wang-Erlandsson, Lan; Destouni, Georgia; Ekman, Annika; Rockström, Johan; Gordon, Line Josefin
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
The semi-arid Sahel is a global hotspot for poverty and malnutrition. Rainfed agriculture is the main source of food and income, making the well-being of rural population highly sensitive to rainfall variability. Studies have reported an upward trend in annual precipitation in the Sahel since the drought of the 1970s and early '80s, yet farmers have questioned improvements in conditions for agriculture, suggesting that intraseasonal dynamics play a crucial role. Using high-resolution daily precipitation data spanning 1981–2017 and focusing on agriculturally-relevant areas of the Sahel, we re-examined the extent of rainfall increase and investigated whether the increases have been accompanied by changes in two aspects of intraseasonal variability that have relevance for agriculture: rainy season duration and occurrence of prolonged dry spells during vulnerable crop growth stages. We found that annual rainfall increased across 56% of the region, but remained largely the same elsewhere. Rainy season duration increased almost exclusively in areas with upward trends in annual precipitation (23% of them). Association between annual rain and dry spell occurrence was less clear: increasing and decreasing frequencies of false starts (dry spells after first rains) and post-floral dry spells (towards the end of the season) were found to almost equal extent both in areas with positive and those with no significant trend in annual precipitation. Overall, improvements in at least two of the three intraseasonal variables (and no declines in any) were found in 10% of the region, while over a half of the area experienced declines in at least one intraseasonal variable, or no improvement in any. We conclude that rainfall conditions for agriculture have improved overall only in scattered areas across the Sahel since the 1980s, and increased annual rainfall is only weakly, if at all, associated with changes in the agriculturally-relevant intraseasonal rainfall characteristics.
Konceptet virtuellt vatten som verktyg för förvaltande av vattenresurser
(2012) Andersson, Axel
Insinööritieteiden korkeakoulu | Bachelor's thesis
Kumulatiivisten vaikutusten arviointi Mekongin valuma-alueella
(2008) Porkka, Miina
Insinööritieteiden ja arkkitehtuurin tiedekunta | Bachelor's thesis