Keystone Links of Anthropogenic Environmental Problems and Emergence of Interconnected Manmade Environmental Crises

Background: Environmental problems are on a hike. The study provides evidenceof the links between manmade environmental issues based on cause-and-effect relationship from real-world examples. For instance, man-made climate change is caused primarily by deforestation, draining of wetlands, intensive farming, and air pollution (greenhouse gas emission). Also, each of these problems, air pollution for instance, is caused by intensive farming, burning of fossil fuels (because of the global energy crisis), urbanization, and methane emission from solid waste dumps. Deforestation is mainly caused by increasedhuman population, poverty, overexploitation of natural resources, urbanization, mining minerals, intensive farming, the establishment of dams, wildres during El Niño, acid rain, and global warming (cyclic as cause and effect). Besides, every man-made environmental problem may cause various other environmental problems, such as air pollution causes ocean acidication, ozone depletion, acid rain, disease, and visual pollution (smog). Similarly, deforestation causes biodiversity loss, land degradation, and human-animal conict. Results: About 252 links were examined among 40 identied environmental issues. In this web, certain causative environmental problems were established as “keystone links”. Possible keystone environmental problems were identied from the concept map based on the criteria given by the following approach, when mitigating a man-made environmental problem, if it results in the permanent disappearance of one or more man-made environmental problems, then that mitigated problem can be considered as a possible keystone environmental problem in a hypothetical situation where human adaptability factors such as economic, social, and political factors are absent. Conclusions: Eight man-made environmental problems were found as keystones such as air pollution, deforestation, population explosion, overexploitation of natural resources, global energy crisis, intensive farming, water pollution-water scarcity, and urbanization-urban sprawl-settlements.


Literature Review
Environmental systems are complex and interconnected (1). Present humans are experiencing the environmental problems that have not been experienced before in this century and they are manmade (1). In 1986 United States Environmental Protection Agency (USEPA) embarked on analyzing the risk caused by more than 30 environmental issues (8, 9) and subsequently United States National Research Council (USNRC) addressed these on the same basis as risk characterization (10,11,9). A "casual model" derived from (12) gives key characteristics of environmental problems such as persistence of the pollutant in the environment, the population exposed and health impacts. Vicky and co-authors (9) have also de ned a sum of 18 speci c descriptors to measure these characters.
In the UNEP (2012) report 21 issues were categorized based on the following criteria: i. Issues that are critical to the global environment. Issues can be either positive or negative. But must be environmental in nature or environmentally related.
ii. Issues that were recognized as 'emerging' based on newness, which can be the result of new scienti c knowledge, new scales or accelerated rates of impacts, increased level of awareness and/or new ways to respond to the issues.
iii. Issues have a large spatial scale, and they should be global, continental, or 'universal' in nature (issues that occur in many parts of the world).
iv. Given priority over the next 1-3 years in the work programme of UNEP and/or other UN institutions and/or other international institutions concerned with the global environment. Man-made environmental problems are interconnected as cause and effect to one another.UNEP report gave 21 emerging environmental issues for the 21st century which were ranked based on their linkages to the various dimensions of sustainable development. These issues cut across major global environmental themes such as food production, food insecurity (E38), urbanization (E10), biodiversity (E05), freshwater (E12), marine (E13, E16, E17, and E18), climate change (E27), energy (E03), technology and waste (E19). In addition, report also concentrated on bridging the technology among countries, giving adequate funds or support to developing countries in order to combat the global environmental change and inclusive green economy. On 25th of September 2015 at United Nation's sustainable development summit, 2030 agenda for sustainable development was developed with the participation of world leaders from over 150 nations. The seventeen Sustainable Development Goals (SDG) are aiming to end poverty (E38), end hunger (E38), ascertain good health (E38) and wellbeing, quality education, gender equality, clean water (E12) and sanitation, affordable and clean energy (E03), decent work and economic growth (E38), develop industry, innovation and infrastructure, reduce inequalities, establishing sustainable cities (E10) and communities (E41), ensure responsible consumption and production (E01), climate change (E27) and disaster risk, protecting aquatic life (E05, E16,E17, E29, E06,&E18), protecting the life on land or secure the biodiversity (E05), democratic governance and peace building and establishing global partnerships to achieve these goals (13). Similarly, in the recent 2012 GEO 5 report, issues such as heavy metal toxicity (E20), invasive or alien species (E42), and water scarcity (E12) such as groundwater depletion (E15) were classi ed along with other modern issues. Two dozen of reports were reviewed by (14) At present, based on above evaluated history on the environmental challenges stated by international authors, treaties, summits and conferences including the research gaps speci ed by (1) which is based on the interconnected nature of the man-made environmental issues, the main hypothesis of this study has been derived, that "Man-made environmental problems are interconnected and complex".

Identifying keystone environmental problems or keystone links
When solving a man-made environmental problem, if it results in the permanent disappearance of one or more man-made environmental problems, then that mitigated problem can be considered as a possible keystone environmental problem.
Based on our de nition of keystone environmental problem to be eligible for a possible keystone environmental problem, mitigation of a man-made environmental problem could solve one or more resultedman-made environmental problems. Accordingly, air pollution can be considered as a possible keystone problem, because if air pollution gets solved, the resulting acid rain and ozone depletion can also come to a halt.
The following literature-based evidence are not su cient to make a rm decision on the term keystone environmental issue because the raw data for statistical calculation is not available. And conclusions cannot be derived from the general comparison of percentile values found in the literature. Thus, the term keystone man-made environmental problems remain a hypothetical term or can be called as possible keystone manmade environmental problem.

Air pollution as a possible keystone environmental problem
Air pollution is not new for this planet because 65 million years ago, during the Cretaceous period, the earth had experienced huge air pollution due to the clouds and smoke formed after the crash of a meteorite. This event caused mass extinction led to the complete elimination of dinosaurs and various other species. Currently, pollution due to natural sources such as forest res and volcano eruption is creating several tonnes of greenhouse gases and other pollutants, which are unable to nd a human solution as they occur naturally.
However, Global emission of CO 2 reached 34.5 billion tonnes in 2012, and the yearly increase was 1.4% from that of 2011 (19). Extreme weather patterns and environmental conditions observed as anthropogenic air pollutants are continuously released to the atmosphere and are increasing in quantity and intensity with time.
In addition to global warming, acid rain and ozone depletion are well recognized for its severity. Man-made  Hubbard Brook is now 80% less than it was in the 1960s. "It has been a big success story," said Gene Likens.
Levels of SO 2 in the USA in the 1970s were 31,218 thousand tons, and the level of SO 2 in the USA in 2017 was 2,815 thousand tons (22). Thus, the reduction of SO 2 in the atmosphere in the period between 1970 and 1917 is 28,403 thousand tons, and the percentage of reduction is 91%. Thus, when it is assumed that the difference between 1960 and 1970 SO 2 levels are small and negligible, it is possible to say a 91% reduction in SO 2 air pollution caused an 80% reduction in the acidity (acid rain) in Hubbard Brook. This is a general conclusion, the raw data of each value for the reduction in the acidity was not available for statistical calculations.

Evidence 2: Air pollution causes ozone depletion
After the Montreal protocol (1987) on substances that deplete the ozone layer, the Chloro uorocarbon (CFC) ban was implemented, and the CFC refrigerators were replaced by ozone friendly product. As a result, the ozone layer is recovering. And the ozone hole is expected to heal completely by 2040-2070. Thus, solving CFC air pollution extenuate the resulted ozone depletion issue. Council (FSC) has reduced the aggregate of deforestation by 5% points, and the incidence of air pollution by 31% points. It had no statistically signi cant impact on re incidence or core areas, but increased forest perforation by 4 km 2 on average".

Evidence2: Deforestation causes biodiversity loss
According to Grosberg, Vermeij, & Wainwright (26), 80% of the species in the world are found in the terrestrial environment. Thus, deforestation causes habitat loss and subsequently leads to loss of biodiversity. Also, most of the human-animal con ict occurs due to the destruction of forest habitats. Increasing industries around the world demand energy, this is primarily generated by consumption of nonrenewable energy resources such as fossil fuels, coal, oil, and gas. Over 80% of current energy needs depend on fossil fuels. Further, electricity generation, transports, and various industries still depend on fossil fuels as the sole source of energy. Energy demand is expected to rise by almost half of the present demand over the next two decades but energy resources have started to run out. The potential for an energy crisis when sources of non-renewable energy get deplete is very true, however, in the past two decades available gas resources have increased by 70%, and oil reserves by 40%, and it has been estimated that we have enough for thirty years supply (32). Besides, new oil and gas elds are being discovered all the time. Advanced recovery technologies open up several unconventional sources such as tar sands, shale gas, and ultra-deepwater are been considered. Furthermore, nuclear energy and increasing usage of technologies of renewable energy sources would pacify future emerging energy needs. However, at present the usage of renewable energy is too small compared to non-renewable sources. The major cause of the energy crisis is the increasing population and their needs for a quality lifestyle which also leads to overconsumption of oil, gas, and coal. However, it is associated with several other factors as given below: -Poor infrastructure: The aging of the infrastructure of power generators is another cause, old and nonupgraded fuel engine consume more fuel than modern or upgraded generators or engines.
Unexplored renewable energy options: renewable energy remains unused in many countries, unlike fossil fuels, renewable energy does not result in greenhouse gases, thus worldwide movement towards clean energy is now a major concern.
Delay in commissioning of power plants: In many developing countries there is a delay in commissioning new power plants that can ll the gap between demand and supply of energy.
Wastage of energy: energy is wasted in many ways such as failure to switching off the electric equipment when there is no need, use of vehicles to travel short distances, not using energy-e cient lights, and fail to use the maximum from daylight (using lights in sunny days) and energy leakages.
Poor distribution system: This causes frequent tripping and break downs.
Accidents and natural calamities: accidents such as oil spills and oil burns due to tanker accidents, explosions in re neries or storage, bursting of the pipeline to mention a few. Natural calamities such as volcanoes, oods, and earthquakes cause destruction and severe loss of fuel too e.g., Fukushima Daiichi nuclear disaster following the earthquake on 11th March 2011, caused several thousand to evacuate from the area, resulted in an economic loss ranging between $250-500 billion and negative attitude towards further development of nuclear power generation.

Wars and terror attacks: Wars between countries could hamper the global energy supply if it happens in
Middle East countries, e.g., Gulf war in 1990 caused a severe rise in oil prices due to oil shortages Miscellaneous factors: tax hikes, strikes, military coup, political events, extreme climatic events may cause an increased demand for energy or affect the fuel or energy supply.
Source: (33) Pandemic -oil prices have even gone negative, uncertainty is very high, and thus production cutting happens.
Global energy crisis and burning of fossil fuels cause overexploitation of coal and other fossil fuel resources.
Further, pollution through mining activities (including fracking); deforestation through intensive farming of oil palm, also cause air pollution (carbon sinks and particle ltration activity are lost through deforestation), the establishment of dams for hydropower generation, etc. Solving the global energy crisis may eliminate several of the above-mentioned problems such as pollution through mining activities (for crude oil & gas), air pollution, and up to certain extent deforestation and intensive oil palm cultivation. It will also solve indirect links such as groundwater contamination by pollution through mining activities -fracking, and biodiversity loss because of deforestation. (see gure 7). [In the gure black circle is the problem being examined, blue circles are cause man-made environmental problems, red circles are effect man-made environmental problems, double lined circles are possible keystone man-made environmental problems, and circles with dashed lines (either single or double lined) are the manmade environmental problems that disappear when the problem being examined (black circle) is mitigated]

Intensive farming as a possible keystone environmental problem
Intensive agriculture is one of the largest contributors to man-made climate change, accounts for around 12% of total emissions, and a quarter of greenhouse gas emission. Animal agriculture accounts for 37% of methane emission and 65% of nitrous oxide. Also, runoff from farms causes eutrophication. Poor living conditions in industrial farms cause animal diseases and animals are said to be subject to cruel handling.
Agrochemicals such as pesticides, fungicides, herbicides, and chemical fertilisers lead to toxic effects on waterways and the atmosphere and affect non-targeted biotas such as insects, birds, and other animals.
Agrochemicals also affect soil micro ora and fauna, cause soil salinisation and deserti cation. A high concentration of nitrate in groundwater from chemical fertiliser causes methemoglobinemia (blue baby syndrome). Nitrate and phosphate e uents from excessive chemical fertilisers lead to eutrophication that resulted in algal blooms that clogs the sh gills, and increases the biological oxygen demand. Intensive palm oil agriculture causes deforestation in Indonesia and affects orangutan habitats. Intensive farming including slash and burn techniques causes severe biodiversity loss and a threat to indigenous people. According to the Department of agriculture, in the United States the number of factory farms increased by 230% from 1982 to 2002. Besides, in the period between 1990 and 2015, pesticide usage worldwide has increased by 73%. Antibiotics and growth hormones used in animal farming also affect humans (37).
Intensive farming results into problems, such as overexploitation of natural resources, deserti cation, deforestation, biodiversity loss, animal slaughtering and cruelty, agrochemicals, solid waste and sewage, eutrophication, groundwater contamination, the establishment of dams, water pollution-water scarcity, wetlands or draining of wetland, and hazardous waste from toxic pesticide chemicals. If intensive farming comes to an end, then problems such as resource depletion, deserti cation, deforestation, animal slaughtering and cruelty, agrochemicals, eutrophication, groundwater contamination, wetlands, and biodiversity loss (to a certain extent) get eliminated. (see gure 8)

Evidence 1: Intensive farming causes agrochemical pollution
Intensive farming with the use of chemical fertilizers and pesticides may result in several environmental issues such as eutrophication, land degradation-sedimentation-soil erosion, loss of biodiversity, overexploitation of natural resources, heavy metal contamination, water pollution, groundwater contamination, hazardous waste, deforestation, air pollution, global warming, solid waste and sewage, dam construction, coral destruction, animal slaughter, and cruelty and food insecurity diseases and poverty. However, based on the concept diagram (see Fig. 5.6) if intensive farming techniques are abandoned and replaced by organic farming or permaculture techniques then agrochemical problems get cease completely. Thus, intensive farming is a possible keystone environmental issue.
According to Feuerbacher, Luckmann, Boysen, Zikeli, &Grethe (38), the study revealed that Bhutan's largescale conversion to 100% organic agriculture by desolating the agrochemical methods resulted in 24% lower yields than conventional yields. The study also found a considerable reduction in Bhutan's GDP, substantial welfare losses, particularly for non-agricultural households, and adverse effects on food security. The reduction in agricultural yield was largely compensated by imported foods from India. And this situation also weakened the country's cereal self-su ciency. Even though soil P and K remained unchanged, soil nitrogen levels gone down by (-22.4%). Because nitrogen release from animal manure was too slow. However, the study also suggested overcoming these pitfalls Bhutan should improve fertilization management, crop protection, and integration of livestock to obtain better yield as truly holistic, organic farming. Thus, Bhutan's present agriculture policy and its implementation revealed that the absence of intensive farming brought the use of agrochemicals to a halt. Thus, it is clear that intensive farming is a possible keystone man-made environmental problem (based on the de nition). However, increasing food demand as the result of an increasing population may question Bhutan's 100% organic policy in the future and it may further increase food insecurity and poverty in the country. Thus, the population explosion acts as the precursor link of major man-made environmental problems.

Evidence 2: Intensive farming causes water pollution and scarcity
According to FAO (39) as cited in (40) "agriculture accounts for 70% of total freshwater withdrawals on average worldwide, thus, agriculture is the largest water user in the world." and "these amounts can reach as much as 95% in some developing countries" (41) as cited in (40). Besides, "agriculture is the major source of water pollution such as nutrient loading, pesticide, and other contamination" (40).

Evidence 3: Intensive farming causes deforestation
According to the report 'Agriculture is the direct driver for worldwide deforestation' (42), "agriculture is estimated to be the direct drive for deforestation. 80% of deforestation worldwide is due to agriculture or intensive farming".
[In the gure black circle is the problem being examined, blue circles are cause man-made environmental problems, red circles are effect man-made environmental problems, double lined circles are possible keystone man-made environmental problems, and circles with dashed lines (either single or double lined) are the manmade environmental problems that disappear when the problem being examined (black circle) is mitigated] 5.1.6 Water pollution-water scarcity as a possible keystone environmental problem According to "www.worldwildlife.org" (43), about 1.1 billion people all over the world lack access to freshwater, and 2.7 billion people nd water scarcity for at least one month of the year. Inadequate sanitation is a problem for 2.4 billion people in the world, where diseases such as cholera, typhoid, and diarrhoea affect. Furthermore, 2 million people, mostly children, die each year from diarrhoeal disease alone. It has been predicted by 2025 two-third of the world population will face water shortages (43). Also, agriculture accounts for 70% of the global freshwater access, but 60% of this water used in irrigation are wasted through leaky irrigation.
In the wastewater, decomposing waste material could produce malodorous gases, sewage consumes dissolved oxygen in the water bodies for its decomposition and raises the Biological Oxygen Demand (BOD) which lead to the sh kills, wastewater rich in nutrients can accelerate the algal blooms and causing eutrophication, as wastewater contains pathogens, toxic chemicals, and heavy metals. The purpose of the development of water treatment plants was initially to satisfy the environmental and health standards. As cities become larger and as the development of industrial processing zones created a huge amount of wastewater every day it increased the amount of wastewater exceeding the natural self-puri cation capacity of streams, ponds, and rivers. See gure 9.

Sources of pollution
Municipal wastewater, industrial wastewater, agriculture runoff, and storm water Evidence 1: Water pollution causes disease and food insecurity According to the Cornell University study (44); (45) as cited in (46), "water-related diseases responsible for 80% of all infectious diseases worldwide, and 90% of all diseases in developing world." Thus, if water pollution is solved completely, we can get rid of 80% of infectious diseases. This is a statistically signi cant solution. Thus, water pollution can be considered as a possible keystone issue.
[In the gure black circle is the problem being examined, blue circles are cause man-made environmental problems, red circles are effect man-made environmental problems, double lined circles are possible keystone man-made environmental problems, and circles with dashed lines (either single or double lined) are the manmade environmental problems that disappear when the problem being examined (black circle) is mitigated] 5.1.7 Urbanization-urban sprawl-settlements as a possible keystone environmental problem According to United Nations (47), today 55% of the world population lives in urban areas, and by 2050 68% of the world population is projected to live in urban areas. The human population has utilized lands for various developmental needs; intense urbanization converts rural and untouched wild habitat areas into more intense use areas such as towns and cities. However, every human occupational role such as agriculture, sheries, hunting, gathering, poultry, dairy, food, and beverage industry, textiles, bre, leather, steel, energy, product manufacturing, transportation, and waste management faces the environmental challenges which cannot be combated in the absence of biodiversity and ecosystem services. Anthropogenic urban sprawl results, nuclear proliferation, war, global warming, coral mining, poaching, ozone depletion, acid rain, overexploitation (e.g. over shing), ocean acidi cation, heavy metal pollution, noise pollution, generation of toxic gases and chemicals, garbage generation, and improper dumping, sewage, oil spills, heavy metal pollution, spreading of According to UN-Habitat, 60% of the global greenhouse emission is from urban cities (48) Agriculture is the direct driver for worldwide deforestation, 80% of deforestation worldwide are due to agriculture or intensive farming (42).
According to FAO (39) as cited in (40), agriculture accounts for 70% of total freshwater withdrawals on average worldwide.
According to "OECD report" (36), fossil fuel combustion accounted for 84% of global greenhouse gas emissions in 2009.
According to International Energy Agency (IEA) WEO-2016b. Special Report Energy and Air Pollution (34) as cited in (35)  E.g., removing deforestation is not possible due to economic needs. And some government policies can in uence severe deforestation (politics).
Thus, creative and intelligent way of nding an adaptable solution to the existing environment is required. And this can be achieved by regenerative solutions, for instance establishing oating wetland is a regenerative solution for eutrophication (see gure 14). Here, no source problem is mitigated as in sustainable solutions. But a bridge link is made by solving another environmental issue (draining of wetlands). Wetland plants absorb the excess nutrients from the intensive agricultural systems, and they can also adapt in density according to the changes in the nutrient ow.
The following concept diagram explains the scenario in a nutshell.
N.B.: -Each problem in the rectangles is connected to many other problems on the basis of cause and effect, and they are not shown here.
In addition, regenerative solutions require less energy compare to sustainable solutions (62). Thus, study provides a way to suggest sustainable to regenerative solutions to the environmental issues. In addition, discovery of keystone environmental problems (e.g. intensive farming in Fig. 2) further simpli es the solution of major environmental problem based on their cause -effect interconnections i.e. when intensive farming is mitigated all other resulted problems such as eutrophication, agrochemical contamination, groundwater contamination, water pollution and scarcity, dams, hazardous agrochemical wastes, deforestation, land degradation and soil erosion (salinization of soil), agricultural solid waste, wetlands (paddy elds), loss of biodiversity (due to mono culture & habitat loss), global warming (methane from cattle farms) and animal cruelty may get disappeared or reduced.
On the whole, the project has several bene ts, such as studying the interconnected nature of the crisis may facilitate the Environmental Impact Assessment (EIA) process and enable us to identify all possible linkages and resulted problems, problem analysis based on the links helps to nd the hidden environmental issues and problem that could emerge when solving another, and concept map also supports the scientists to predict future environmental problems based on the links.

Conclusions
All man-made environmental problems are interconnected based on cause-and-effect relationships. Study was conducted using qualitative content analysis methodology. When mitigating a man-made environmental problem, if it results in the permanent disappearance of one or more man-made environmental problems, then that mitigated problem can be considered as a keystone environmental problem, in a hypothetical situation where human adaptability factors such as economic, social and political factors are absent.
Following eight man-made environmental problems were identi ed as keystone environmental crises by the study, such as air pollution, deforestation, population explosion, overexploitation of natural resources, global energy crisis, intensive farming, water pollution-water scarcity, and urbanization-urban sprawl-settlements. The Gaia hypothesis rst proposed by James Lovelock in 1969 stated "all living things on earth function as one super organism that changes its environment to create conditions that best meet its needs". In addition, hypothesis further justi es, that all living things (super organism) poses the ability to self-regulate the system by successfully adapting to the changes or by overcoming the changes by its natural resilience. This cooperative not competitive process ascertains the continuity of life on this planet through evolution. However, in this Anthropocene era man-made environmental problems severely affect this natural self-regulating and co-operative phenomenon. Man-made environmental problems are the human caused changes in the environment that alters the surrounding and makes it unfavourable for life existence. According to (1), in the early days environmental issues gained public attention due to either their impacts on communities or prediction of such problems by scientists and others on likely effects of certain issues before these problems capture the wide recognition. According to (1), early environmental issues such as sh kill in contaminated surface waters, smog hazes over many American cities, the effects of DDT and other pesticides on wildlife, effects of acid rain on ecosystems, effects of lead on infants and children, effects of tributyl tin on marine environment were considered as environmental problems and increased public concern on these issues caused US EPA to pass few laws in order to protect the environment and people such as clean air act, clean water act and safe drinking water act. As a result, problems such as lead poisoning, air and water pollution were successfully mitigated in the period between 1978 and 1995. In addition, international treaties such as Montreal protocol (1987) which led to take measures to protect stratospheric ozone layer by banning CFC and related products globally and enabled us to recover from the impacts of UV radiation. It is further stated in the (1), that environmental systems are complex and interconnected.

Abbreviations
Interestingly, man-made environmental issues are on a hike. During 1960s people aware on pesticide pollution as they read on Rachel Carson's Silent Spring but none had ever heard the term plastic pollution and e-waste issue. Even global climate change, ocean acidi cation, ozone depletion and acid rain are not so prominent at that time. Similarly, Aldo Leopold's "The Land Ethic" referred his work in forestry and wildlife, and "Sand country Almanac" was a literature on environmental movement. In addition, "State of the world" series by world watch institute discussed about trends in sustainable development and issues such as population, energy, agriculture, health, and trade policy. In 1970's the book named "Soft energy paths" by Amory B. Lovins discussed about renewable energy sources such as solar, wind, geothermal, biofuel, etc. A book named "Natural capitalism" authored by Paul Hawken, Amory B. Lovins, et al. noted issues related to natural capitalism, brings out ecologically smart choices for business on natural resources. "The Ecology of commerce" authored by Paul Hawken proposes a business culture in which natural world is allowed to ourish while the planet's needs are considered. "Steady state economics" ( rst published in 1977) is a widely accepted book in economics of sustainability authored by Herman Daly. The book "Population bomb" by Paul R. Ehrlich (1968) on population explosion predicted the possibility of mast starvation in the period between 1970 and 1980 and also called immediate action to this problem, "Our stolen future" authored by Theo Colborn advocated the impact of chemical pollution on human health as well as on the environment and it evidenced that birth defects, sexual abnormalities and reproductive failures occur due to the intense chemical usage, and the book "Scarcity and growth" by Harold J. Barnett and Chandler Morse expressed that the resource depletion does not affect the economic growth. I personally felt the need of more up-to-date knowledge on present status of the world environmental crisis, the same also mentioned in the GEO 6 report (Global Environmental Outlook of UNEP). Therefore, I also published several books on each environmental issue; books are available on amazon.com (or www.envo.yolasite.com). The games such as 'Enviropoly' and 'Green master's playing cards are designed not only as awareness air but also as a teaching tool for environmental education. In addition, I also have investigated the interconnected nature of man-made environmental problems. It is quite obvious that man-made environmental problems are interconnected as causes and effects. For instance, intensive farming causes agrochemicals, agrochemicals cause eutrophication. Similarly, greenhouse gas air pollution causes man-made global warming. I would like to examine the interconnected nature of the man-made environmental problems. The research can be designed as literature survey in order to demonstrate the existence of each links or the work that can be extended using a research on any identi ed man-made environmental problem. However, based on my six years of work experience as an environmental o cer at Environmental Impact Assessment unit, Central Environmental Authority, Sri Lanka, I have come across several site inspections such as sanitary land lls, industrial sewage treatment, Air pollution control, eutrophication, deforestation and agroforestry, etc. (please see my resume).
My current research interest falls on remediation and restoration of degraded environmental systems, as my pilot study on interconnected nature of environmental crisis may lead to the identi cation of keystone manmade environmental problems for the rst time in the world. I have conducted research works in most important environmental issues in Sri Lanka such as impact of use of inorganic fertilizer for tobacco cultivation on groundwater nitrate problem in Jaffna peninsula and study on distribution and abundance of beach trash in Colombo district, as Sri Lanka is ranked in the 5 th place among world's most ocean trash producing countries.
Thus, my interest in man-made environmental problems is not just a greed for a Ph.D. title but my life itself. However, I have successfully completed my Ph.D. on the same. I'm living with this broad inspiring mission, and participated in several environmental awareness programmes such as awareness march and awareness beach cleanups on Ocean pollution on world Ocean day (8 th of June) and programmes on world biodiversity day (22 nd of May) etc. I swear if this paper selected for publication, it will ignite the spark throughout the world through this new discovery of keystone man-made environmental problems. Funding:

Not Applicable
Authors' contributions Sivaramanan S: This paper is the outcome of the doctoral research. The data collection, literature writing, documentation for results, construction of concept map, analysis, nding key links and de ning keystone environmental problems, drafting discussion and conclusion done by this author. This interconnected environmental problem was initiated with the development of a board game 'Enviropoly' (2017) then author converted the concept of his own game into a study with the support of the supervisor.
Kotagama SW: Professor guided and supervised the study. He played a major role as time to time discussed with the researcher (Sivaramanan S) and suggested ways for improvements, professor also proof read and ameliorated the entire thesis document at the end of the study. Many grammatical and theoretical errors were corrected by him before the acceptance. All authors have read and approved the manuscript, and ensured that this is the case.