Author: Ana Gelevska

Advancing Sustainable Agriculture to Feed Earth’s Growing Population

Feeding a growing global population, sustaining global economic stability, and improving quality of life requires methodologies that effectively manage the interrelated food-energy-water (FEW) systems. Providing sustainable food, water, and energy for 9.7 billion by 2050 in a manner that does not jeopardize the environment is undoubtedly the most thought-provoking challenge of today’s society.

Increased demand for food, water, and energy in the next 30 years will increase the pressure on environmentalists and governments. The demand itself is troubling as climate change exacerbates the pressure on our resources. Storms and other severe weather occurrences increase the chances of disruptions in the food supply chain and energy distribution. Additionally, the land area required to make food production feasible is already in use. The land tat hasn’t been used includes tropical forests and grassland reserves, which sustain biodiversity and ecologically sensitive areas. Adding new land is not an option for increased food supply, therefore increasing the effectiveness and yields in the existing agriculture, and decreasing food waste globally is required to ensure sustainable food production

The Food, Energy, and Water Nexus

Successful FEW projects have a bright future with higher chances of providing effective results while using a transdisciplinary approach. The policies and practices of ecological modernization and sustainable supply chains directly impact the food-energy-water nexus from commercial and industry perspectives. Providing a sustainable supply of F-E-W while considering land-use practices, changing demands in consumer preferences, and climate variability requires the joint involvement of science, engineering, technology, industry, business, and governments.  

A transdisciplinary approach investigates a broad range of factors that address sustainability, and provides the most suitable solutions. This approach researches different phenomena based on reductive, reasoned, and detailed studies. For example, the food production capacity increased with the discovery of chemical pesticides and their implementation in agriculture. As discussed in Rachel Carson’s Silent Spring, the enormous ecological costs opened a new perspective for upgrading the U.S. environmental policy. This opens the opportunity for solving problems with global significance. The multi-level structure of the nexus provides opportunities for identifying gaps and addressing ineffective production practices.   

FOOD REVIEW  

Increasing Agricultural Yields with Reduced Environmental Impacts

Advancement of mechanization and usage of fertilizers, pesticides, plant breeding, and irrigation technology has significantly improved agricultural yields over the past century. Such advances have ensured economic benefit by generating a trade surplus in many countries. Computational science and data analysis provide opportunities for future enhancement and increase yields for the increasing population. For example, imaging sensors can detect and diagnose plant diseases, detect greenhouse gases, and reduce the potential decrease in agricultural productivity. Applications can estimate the appropriate amount of pesticides and other chemicals and minimize agrochemical use without compromising the quality and quantity of the yields. Genetic engineering has proven highly effective in developing crop varieties that provide the highest productivity under the extreme impact of climate change. The resilience and efficacy of agricultural production can be achieved with a deeper understanding of plant genetics, farm management practices, local conditions, and a complex set of sciences that will facilitate these advances.

Reducing Food Waste

The most significant opportunity to stabilize the food supply for the growing population is reducing food waste globally. It is estimated that approximately one-third of all food produced is lost or wasted. Each step of the food chain incurs certain losses such as spills in the field, transportation can cause damages or degradation to food, end consumers tend store food inadequately, or simply throw away their food. In lesser-developed countries, over 85% of food waste occurs before the food reaches end consumers, while approximately 30% of food waste occurs at the consumer level in more-developed countries.

Reducing food loss requires technologies and systems to be implemented throughout the food chain– from harvest, processing, distribution, and storage. For instance, nanotechnology-based protective films can increase the shelf life of various products. Sensors can estimate food quality and could reduce food loss. Last but not least, strategies and plans are needed to inform the end consumers about all risks and damages that food waste causes.

In addition to increasing agricultural yields and reducing food waste, shifting dietary patterns is another effective method for reaching a sustainable food supply. Considering the fact that 14.5% of greenhouse gas emissions are caused by livestock farming, the shift in dietary patterns could reduce the environmental damage and resource burden of feeding the increasing world population. According to World Resources Institute estimations, nutritional changes could provide food for approximately 30% more people with the same area of agricultural land.

WATER REVIEW  

Overcoming Water Scarcity

Surface water and groundwater resources that supply ecosystems and the human population are increasingly stressed. it is estimated that global water use will increase by 55% by the year 2055. Freshwater is a limited resource as it makes up only 0.77% of all water on Earth. While these resources remain constant, the distribution is widely impaired in different areas. When water demand exceeds the available water supply, competition for available resources occurs. This is known as water scarcity. Today, we are already facing water scarcity as 2.8 billion people worldwide face water scarcity for at least one month annually. Those who live in water-stressed regions are highly vulnerable to extreme weather events such as droughts and environmental degradation.

Innovations in Water Supply and Increased Efficiency of Water Use

Regions faced with water scarcity have devised ways to create freshwater from seawater through desalination processes. This process involves turning seawater into fresh water through reverse osmosis and distillation. As of 2015, over 18,000 desalination plants have produced nearly 23 billion gallons of freshwater per day. However, these technologies are expensive and energy-intensive, making them unsuitable for widespread solutions. Lower-energy approaches have been tested to provide a suitable alternative to desalination plants. One approach utilizes sunlight to activate a heat-absorbing membrane that is embedded with nanoparticles to distill seawater. This type of innovative technology could provide off-grid desalination at the household or community scale.

Scientists are developing technologies for water supplies through the recovery and reuse of municipal wastewater, stormwater, greywater, and contaminated groundwater. New technologies are looking for solutions to collect wastewater in cities or neighborhoods and treat it for non-potable uses, such as irrigation, street cleaning, fire-fighting, industrial processes, heating and cooling, etc.

Reduced water use is another equally important measure toward achieving water sustainability. Emerging technologies offer a variety of opportunities to increase water use effectiveness. This will provide optimal water use for the growing population and future generations as well. Agriculture would greatly benefit from these techniques as the largest water user globally. For example, engineering solutions in agriculture have utilized including precision irrigation tools, advanced ground-based sensors, and remote sensing data to gauge irrigation needs more precisely.

Redesigning and Revitalizing Water Distribution Systems

In the early and mid 20th century in high-income countries, water treatment and innovation of distribution systems contributed to significant improvements in public health. However, over time, and with the growing populations, these systems have outlived their intended lifespan. Old distribution pipes need restoration and replacement to provide water reliability and efficiently.

ENERGY REVIEW  

Providing Clean Energy to Meet Growing Global Demand

The economic growth of countries, increased productivity, and improved living standards are almost entirely dependent on the delivery of energy services. As the population grows, global energy needs are expected to increase. The U.S. Energy Information Administration projects that global energy consumption will grow by 28% between 2015 and 2040. As temperatures rise from the effects of climate change, the global energy demand from air conditioners will triple from 2016 to 2050, leading to the requirement for new electricity capacity equivalent to the capacity of the United States, the European Union, and Japan combined. 

Switching to More Sustainable Energy Sources

There are many options for producing energy with little to no carbon dioxide emissions. Solar , wind-based energy, hydropower, waves energy, and geothermal energy are the most promising renewable sources. However, governments and environmentalists have yet to determine the environmental impacts, economic costs, and benefits of renewable energy sources. For instance, wind and solar projects will reduce CO2 emissions, but, their implementation for widespread usage requires land area for installation, additional service roads, and installation of such systems can affect recreational purposes of the environment. Additionally, producing renewable energy components increases the environmental and economic costs.     

Finding Ways to Get Energy Where It Is Needed

Advances in production, transmission, and energy storage, combined with reduced costs, renewable energy technologies, and replacing traditional energy sources will provide access to reliable renewable energy supplies worldwide. A promising solution for locally-generated electricity is the usage of renewable “microgrids.” This would provide energy to remote regions that are not connected to conventional power grids through solar panels, wind, or hydropower. Alaska has been the leader in developing microgrids since the 1960s, and today, 70 microgrids contribute about 12% of the renewable energy used globally.

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Ranganathan, J., D. Vennard, R. Waite, P. Dumas, B. Lipinski, & T. Searchinger. (2016). Shifting diets for a sustainable food future. World Resources Institute. Retrieved from https://www.wri.org/research/shifting-diets-sustainable-food-future.

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Water

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van Dijk, A. I. J. M., Beck, H. E., Crosbie, R. S., de Jeu, R. A. M., Liu, Y. Y., Podger, G. M., Timbal, B., and Viney, N. R. (2013). The Millennium Drought in southeast Australia (2001–2009): Natural and human causes and implications for water resources, ecosystems, economy, and society, Water Resources Research, 49. Retrieved from https://doi.org/10.1002/wrcr.20123.

Energy

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Climate

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Wetlands are biodiverse ecosystems that provide a wide range of services from food security, climate change mitigation. Healthy and functioning wetlands are crucial for humans through ecosystem services. However, human activities can impact the quality of a wetland’s drainage pattern, pollution concentration, and disrupted flow regimes. Wetlands are estimated to cover a global area almost as large as Greenland, but their area is declining extremely fast. With over 35% losses since 1970, this puts wetland plants and animals in crisis, where a quarter of species are endangered and at risk of extinction (Gardner et al., 2015).

Despite all the ecological benefits wetlands provide, these ecosystems are often neglected and have received little attention from policy-makers, conservationists, and scientists when discussing climate change and biodiversity protection. Many areas globally, such as the mangroves of South-East Asia, the marshlands of South America, and the swamps of Central Africa, are being drained and dammed at higher rates.  

The 26th UN Climate Change Conference of the Parties (COP26) took place in Glasgow last fall. All parties involved agreed to accelerate action towards the goals of the Paris Agreement and the UN Framework Convention on Climate Change. Nations lined up to pledge an end to deforestation, and the leaders of more than 100 countries with approximately 85% of the world’s forests agreed to end deforestation by 2030. This agreement is a type of re-signing of a few equivalent promises for ending wetland loss. According to a statement by Achim Steiner, executive director of the United Nations Environment Programme, in over 100 years, human activities have contributed to destroying 50% of the world’s wetlands. A report published by Nick Davidson indicates that wetland loss may have totaled to 87% since 1700 (Davidson, 2014). There has been a much faster rate of wetland loss during the 20th and early 21st centuries, with a loss of 64–71% of wetlands since 1900 (Davidson, 2014). This loss occurs at a faster rate than for any other major ecosystem. 

In a paper supported by Intergovernmental Panel on Climate Change (IPCC), author, Hans Joosten, highlights the importance of wetlands as highly space-effective carbon stocks. For instance, peatlands cover approximately 3% of the global land area, but contain more carbon than the entire forest biomass of the world (Joosten, 2015). Drainage of these areas leads to carbon and nitrogen release as greenhouse gases to the atmosphere. Statistical data shows that as a result of 15% of the peatlands that have been drained, the global anthropogenic CO2 emissions were increased by 5% (Joosten, 2015). Additionally, the destruction of these ecosystems decreases the peatlands’ capacity for water purification, flood control, and habitat provision for specialized biodiversity. This only highlights peatlands’ vital role in national climate change mitigation policies.

Wetlands have the ability to store water and release it to maintain river flows after rain events. This sponge-like feature protects us from floods and disastrous storm events. In mid-July 2021, the Kyll river close to the German-Belgian border over-flowed into neighboring towns (Madgwick, 2022). The flooding took more than 220 lives and cost an estimated $40 billion for repairs. The rainstorm that caused the flooding was unparalleled, but there is another hidden contributor to the floods. Land use across Europe has been dramatically changed, and the destruction of natural wetlands limits the capacity to absorb heavy rains, leaving river-side towns vulnerable to flooding events (Madgwick, 2022).

Another unique ability of wetlands is protection against wildfires. Healthy peatlands have the natural ability to hold decaying moss and water to support a living rug of a unique fire-resistant moss called sphagnum. This feature enables these areas to act as a fire break and prevent fires from spreading across a wetland.

Ultimately, all water systems need protection and restoration. It would not be compelling enough if we focused on wetlands rehabilitation alone. These systems work in concert with each other and must be considered in all policies geared towards climate resilience and ecosystem protection.

Sources:

Davidson, N. C. (2014). How much wetland has the world lost? Long-term and recent trends in Global Wetland Area. Marine and Freshwater Research, 65(10), 934–941. https://doi.org/10.1071/mf14173

Gardner, R., Barchiesi, S., Beltrame, C., Finlayson, M., Galewski, T., Harrison, I., Paganini, M., Perennou, C., DE, P., Rosenqvist, A., & Walpole, M. (2015). State of the world’s wetlands and their services to people: A compilation of recent analyses. Ramsar Briefing Note No. 7. Gland, Switzerland: Ramsar Convention Secretariat. Retrieved from: http://dx.doi.org/10.2139/ssrn.2589447

Joosten, H. (2015). Peatlands, climate change mitigation and biodiversity conservation. Nordic Council of Ministers. Retrieved from: https://www.ramsar.org/sites/default/files/documents/library/ny_2._korrektur_anp_peatland.pdf

Madgwick, J. (2022). Opinion: Germany needs to invest in nature to defend against floods: Deutsche Welle. Retrieved from https://www.dw.com/en/opinion-germany-needs-to-invest-in-nature-to-defend-against-floods/a-60607186

What Is Fracking— And Why Is It So Controversial?

Hydraulic fracturing, also known as fracking, is a technique that involves the fracturing of bedrock formations by a pressurized liquid. Namely, the “fracking fluid” is a combination of water, sand, and chemicals injected underground at a very high pressure to crack open hard rock layers to release the oil and/ or gas trapped inside.

Fracking is not a new technique. In fact, this procedure began as an experiment in 1947, and its successful application followed a few years later in 1950. This technique for extracting gas and oil has become more widespread in recent years. In the mid-2000s, many companies discovered that the extraction would be cost-effective by combining fracking with methods such as horizontal drilling. This “fracking boom” has reshaped the energy landscape, especially in many states including North Dakota, Texas, and Pennsylvania. Since 2012, approximately 2.5 million jobs have been created worldwide on oil and gas wells, 1 million of those jobs are within the U.S.  

On the one side, fracking creates jobs, boosts manufacturing, and reduces the amount of coal used in other drilling processes. However, many opponents argue that this industry has lax regulations, increases air pollution, contaminates groundwater and surface water, and creates human health problems.      

How Does Fracking Work?

The procedure of hydraulic fracturing and horizontal drilling to extract oil or gas is a complex process that involves several steps. The basic fracking operation begins by drilling a hole called a “wellbore” that extends up to the layer of gas-rich shale. The shale layer can be as deep as 5000 feet (approx. 1.5 km), and drilling can last up to one month. In this step, the well is lined with a steel casing to prevent groundwater contamination in the area. Once the drill gets to the shale layer, it slowly turns and starts drilling a horizontal well along the rock. The next step involves puncturing tiny holes in the horizontal section of the shale layer with a “perforating gun” loaded with explosive charges. The fracking fluid is then pumped into the well at extremely high pressure and penetrates through the tiny holes, which cracks the shale. The sand from the mixture holds the cracks open while the chemicals extract the natural gas and allow it to travel up the pipe. Once this stage is finished, the water and chemicals flow back out of the well and are adequately removed for disposal or treatment.

Via pipe network, the gas is shipped to consumers. Typically, a well has the capacity to produce gas for 20-40 years, a period during which thousands of cubic feet of gas each day are extracted. Depending on the geology of the region and the technology used, the process of fracking has many variations.                  

How Has Fracking Changed Our Future?

As previously mentioned, natural gas can be used as a substitute for coal. But, will this procedure outweigh the gains from using a cleaner fuel and minimize environmental damage?  

Fracking is a high-risk procedure, and its benefits do not outweigh its consequences. Why? There is a common misconception that natural gas is a cleaner alternative to coal. Coal produces harmful byproducts, including large amounts of soot compared to natural gas. Still, Intergovernmental Panel on Climate Change (IPCC) reports that the carbon content of natural gas – methane is 34 times greater than that of carbon dioxide over a 100-year time scale. The Environmental Protection Agency (EPA) reported that the global warming potential of methane is 21 times greater than that of carbon dioxide over a 100-year time scale (EPA, n.d.).

Fracking also poses a threat to the environment, starting with the fracking fluid. Based on the rock type and the specifics of the site, different chemicals are added for various purposes. For example, acids are used for dissolving minerals to ease the fossil fuel flow; biocides are added to eliminate bacteria; gelling agents are used to carrying proppant into fractures; corrosion inhibitors are added to protect the steel parts of the well. EPA identified 1084 different chemicals used in the fracking process between 2005-2013, including methanol, ethylene glycol, and propargyl alcohol, most of which are hazardous or potentially hazardous to human health, or their impact is unknown (Denchak, 2019).

Fracking also poses a risk to groundwater resources. The landscape in North America has been altered by directional drilling and high-volume hydraulic fracturing (HVHF) due to increased oil and gas production. Since 2017, the Pennsylvania Department of Environmental Protection (PADEP) has issued 302 letters to homeowners documenting incidences of presumed groundwater contamination from oil and gas development (Barth-Naftilana et al., 2018). At that time, there were 10,908 unconventional wells drilled in Pennsylvania. There are disagreements regarding the causes of water-quality impairments, which require additional observations to understand and resolve the issue.

Other issues tied to fracking include:

• Wastewater disposal issues;
• High water usage (EPA estimated that in 2010, approximately 70-140 billion gallons of water were used to fracture 35,000 wells in the U.S., which is equal to the annual water consumption of 40-80 cities, each with 50,000 citizens);
• Contamination of drinking water (EPA linked fracking with local contamination of drinking water in many states, including Pennsylvania, Colorado, Ohio, and Wyoming);
• Poor infant health (Science Advances published a study which found that babies born within half a mile radius of a fracking site have significantly higher chances of low birth weight and are more likely to suffer from poor health).
• Habitat destruction (creation of fracking wells takes place at the expense of the destruction of local habitats; as a result of fracking, in Wyoming, between 2001 and 2010, the reduction of mule deer’s habitat resulted in a decrease of 56% of their population);
• Earthquakes (According to the United States Geological Survey (USGS), Oklahoma has the most induced earthquakes in the U.S., and 2% can be linked to fracking. In 2018, the state of Texas experienced the largest hydraulic fracturing induced earthquake with a magnitude of 4.0).

Technologies and Methods That Can Make Fracking Cleaner 

While fracking is not the most sustainable and eco-friendly replacement for coal, some technologies and methods can make this procedure cleaner. Traditional fracking systems operate with large quantities of water; therefore, usage of water-free fracking systems can gather the same results as using water. For example, gelled fluid containing propane, uses one eighth of the liquid traditionally required and pumps the liquid at a substantially lower rate. Another option is to replace freshwater with recycled water or brine. This switch will conserve fresh water and, at the same time, will reduce the water pollution caused by traditional fracking systems.

Fracking produces high amounts of wastewater, containing chemically treated water. Although the wastewater is shipped to underground storage facilities, the introduction of wastewater purification could reduce potential pollution and allows the water to be reused in the fracking process.  

Methane leaks are one of the primary concerns of fracking. The most effective methods in reducing methane leaks are using an infrared camera to detect leaks at fracking sites and replacing traditional pressure-monitoring pneumatic controllers with lower-bleed designs. Interestingly, an article by National Geographic indicated that replacing those controllers could reduce methane leaks by up to 35 billion cubic feet annually (Kiger, 2014).

Sources:

Barth-Naftilana, E., Sohnga, J., & Saiersa, J.E. (2018). Methane in groundwater before, during, and after
hydraulic fracturing of the Marcellus Shale. Proceedings of the National Academy of Sciences, 115(27). Retrieved from: https://www.pnas.org/doi/pdf/10.1073/pnas.1720898115

Denchak, M. (2019). Fracking 101. Natural Resource Defense Council. Retrieved from: https://www.nrdc.org/stories/fracking-101

Environmental Protection Agency. (n.d.). Understanding global warming potentials. EPA. Retrieved from: https://www.epa.gov/ghgemissions/understanding-global-warming-potentials

Kiger, P. J. (2014). Green fracking? 5 technologies for cleaner shale energy. National Geographic. Retrieved from: https://www.nationalgeographic.com/science/article/140319-5-technologies-for-greener-fracking

Population change and economic development are closely linked, and the growth and expansion of cities occur mainly due to the transition from rural to urban societies. The promises of increased economic opportunities and accessible health care, education, and transportation are among the most important reasons encouraging people to move. This fundamental demographic process makes significant changes in the population of urban places, making the rural-to-urban transitions often chaotic. 

The rapidly developing urban centers, defined as megacities with a population of 10 million or more, present a unique opportunity to study the future of our planet and how to make it more resilient and sustainable. Today, the world population is concentrated in cities, and this trend will continue in the future. The predictions are that by 2030, two-thirds of the world’s population will reside in urban areas, and there will be 41 megacities, of which more than 80% will be in low and middle-income countries. On the one side, megacities are culturally, socioeconomically, and racially diverse, while environmental heterogeneity exists in those areas. Future comprehensive studies of megacities should focus on common issues and consider the complex health outcomes of the natural and built environmental landscapes (Patel & Burke, 2009).

If megacities can successfully provide safety and security, there might be several benefits of living in megacities. The declining population in rural areas will reduce the stress on natural environments, while the increasing population in cities will provide effective aggregation of the limited resources. However, the high-density population of megacities makes the citizens exposed to various threats of disasters. Traditionally, the disasters are either natural (hurricanes, floods, earthquakes, etc.) or technological disasters (radiation leaks, oil spills, infrastructure collapses, derailments, etc.). It is undeniable that great opportunities and significant challenges accompany the rise of cities around the globe. Many world regions have increased the number of city dwellers, which makes the questions about the safety and health of the dense environments paramount.

Today, 55% of the world’s population lives in urban areas, and considering the UN predicts that by 2050, this number is expected to increase to 68%. The gradual shift from rural to urban areas, combined with the overall population growth, could add 2.5 billion people to urban areas by 2050. Approximately 90% of this increase will take place in Asia and Africa (UN, 2018).

Food security is one of the most common issues in urban-build environments. Namely, megacities are often poorly equipped and cannot provide stable food sources for sustaining massive populations. Low and middle-income megacities face severe food shortages and poverty due to increased food prices and malnutrition. Moreover, megacities face increased BMIs (body-mass index) due to sedentary lifestyles and shift toward a western diet (Saquib et al., 2016).

The extremely rapid growth of population in megacities causes significant challenges in the accommodation of the citizens, which often leads to unplanned and underserved areas. Homelessness, squatting, and slum areas are described as areas of overcrowded, poor, informal forms of substandard housing. Slums lack access to clean drinking water and sanitary facilities, and residents often don’t have the power over the land they occupy. A report by the UN shows that over 1 billion people live in slums or informal settlements, with 80% attributed to three regions: Eastern and South-Eastern Asia (370 million), sub-Saharan Africa (238 million), and Central and Southern Asia (227 million). It is estimated that by 2030, over 3 billion people will require adequate and affordable housing (UN, 2019).

Air pollution is another serious problem that affects the well-being of all people globally. Statistics show that over 92% of the global population is exposed to higher than recommended concentrations of PM2·5, which is the cause of 3 million premature deaths annually. Megacities are the areas with an extremely high concentration of these substances, and exposure can cause fatal health conditions, including stroke, chronic obstructive pulmonary disease, and lung cancer (WHO, 2016).

Urban-heat-island effect is another negative consequence of living in megacities. This atmospheric phenomenon is characterized by temperatures increasing by 40-50 °F in the city compared to surrounding areas. This vast difference in temperatures leads to higher incidents of dehydration, heatstroke, and cardiovascular and respiratory diseases. The high temperatures encourage increased use of cooling systems that release greenhouse gases into the atmosphere, further aggravating the heat-island effect (Campbell-Lendrum & Corvalán, 2007).

Megacities face a significant challenge in providing clean, running water and sewage removal, essential for disease control and decent living. Additionally, the old colonial infrastructure of some megacities makes dealing with the volume of new materials in sewer systems more complex. The lack of freshwater to meet the standard water demand occurs due to drought, leaking infrastructure, and unsustainable groundwater extraction. It is projected that from one-third of the global urban population in 2016 (933 million), by 2050, approximately one third to nearly half of the global urban population (1.693–2.373 billion people) will be affected by water-scarce urban population, with India projected to be the most severely affected (increase of 153–422 million people) (He et al., 2021).

Traffic in megacities is heavy and odious. With over 10 million residents, traffic in megacities has two problematic features. First, vehicle variation inhibits the movement. It is not uncommon for some megacities with different types of transportation to share the same roads all of which move at different speeds and have different maneuverability. As a result, the flow is blocked, and all traffic participants cannot move effectively. Moreover, as part of unsustainable urban development, traffic increases air pollution and causes health risks associated with harmful pollutants. This ultimately has severe economic and social costs. Despite the fact that many well-developed megacities have made significant progress in reducing air pollution, there are still many challenges in achieving clean and breathable air, among other issues.   

Other challenges associated with urban-built environments include overcrowding, a scarcity of open space, inadequate electricity supply due to high demand, high levels of inequality, unemployment, urban violence, etc.​

To answer the initial question: are megacities safe for a living?

If they are adequately managed, megacities have fantastic potential to reduce poverty and improve living conditions for millions of people. Still, considering all of the facts listed above, it is safe to conclude that megacities may not always be the best choice. Each individual can make most of the advantages that megacities offer and try to make the planet a better living place. Starting with small choices, we all can make megacities healthier and more tolerable.  

Sources:

Campbell-Lendrum, D., Corvalán C (2007) Climate change and developing-country cities: implications for environmental health and equity. Journal of Urban Health, 84, 109-117.

He, C., Liu, Z., Wu, J. et al. (2021). Future global urban water scarcity and potential solutions. Nature Communications 12(4667) . https://doi.org/10.1038/s41467-021-25026-3

Patel, R.B. & Burke, T.F. (2009). Urbanization—An emerging humanitarian disaster. The New England Journal of Medicine, 361, 741-743.

Saquib, J., Saquib, N., Stefanick, M. L., Khanam, M. A., Anand, S., Rahman, M., Chertow, G. M., Barry, M., Ahmed, T., & Cullen, M. R. (2016). Sex differences in obesity, dietary habits, and physical activity among urban middle-class Bangladeshis. International journal of health sciences, 10(3), 363–372.

United Nations. (2019). Sustainable development goals- 2019 report. UN Department of Economic and Social Affairs, Statistics Department. Retrieved from: https://unstats.un.org/sdgs/report/2019/goal-11/.

United Nations. (2018). World urbanization prospects: The 2018 revisions. UN Department of Economic and Social Affairs, Population Department. Retrieved from: https://population.un.org/wup/publications/Files/WUP2018-Report.pdf.

World Health Organization. (2016). Ambient air pollution: a global assessment of exposure and burden of disease. World Health Organization. Retrieved from: https://apps.who.int/iris/handle/10665/250141.

What Is the Greenhouse Effect?

The greenhouse effect is a natural phenomenon that helps maintain the average temperature level of 15°C on the Earth’s surface. In this process, the thermal radiation from Earth’s surface is reabsorbed by greenhouse gases and then radiated in all directions, which provides thermal regulations for all living species on Earth. Namely, the greenhouse effect is indispensable for life because, in its absence, the average temperature would be minus 18°C.

The Earth’s atmosphere is a gaseous layer that surrounds the planet and is retained by the Earth’s gravity. The light from the Sun, invisible ultraviolet and infrared wavelengths penetrate the planetary atmosphere, and oceans and land naturally absorb approximately 70% of this solar radiation. The rest is reflected in space, but the real issue is the radiation absorbed in our atmosphere. Greenhouse gases retain the radiation in the atmosphere, thus increasing the planet’s average temperature. 

While the natural greenhouse effect is essential for the Earth’s climate and all living creatures, the increased amount of greenhouse gases in the atmosphere is a global issue that affects all living species. The CO2 released from the burning of fossil fuels, over time, accumulates and creates a so-called “insulating blanket” around the Earth, which traps the Sun’s heat in the Earth’s atmosphere and ultimately increases the average temperature. In other words, the release of CO2 contributes to the current intensified greenhouse effect.     

Which Gases Cause the Greenhouse Effect?

Greenhouse gases and the balance of the greenhouse effect depend on three factors: how much heat is absorbed, how much of the heat is re-radiated, and how much of it is in the Earth’s atmosphere. Gases that contribute most to the greenhouse effect are water vapor (H2O), carbon dioxide (CO2), nitrous oxide (N2O), methane (CH4), and ozone (O3).

The gases mentioned above have different power of absorption and re-radiation, also known as global warming potential (GWP). The greenhouse gas’s ability to trap extra heat in the atmosphere relative to carbon dioxide (CO2) is most often calculated over 100 years and is called the 100-year GWP. Interestingly, methane is 23 times more effective, and nitrous oxide is 296 times more effective than carbon dioxide. Still, there is a substantially higher amount of carbon dioxide in the Earth’s atmosphere than methane or nitrous oxide.

The greenhouse gases emitted into the atmosphere do not remain there indefinitely. For instance, the amount of carbon dioxide released into the atmosphere and the amount of carbon dioxide dissolved in the water surface of oceans are in constant equipoise because air and water mix well at the surface.

Anthropogenic Greenhouse Gases 

Since the start of the Industrial Revolution, human activities have changed the environment considerably. This includes increased concentrations of greenhouse gases in the atmosphere. The primary sources of anthropogenic greenhouse gases are burning fossil fuels, agriculture and forestry, cement manufacture, and aerosol emissions.  

• Burning fossil fuels

Scientists at NOAA Climate stated that carbon dioxide levels are considerably higher than in the last 800,000 years. Human activities add more carbon dioxide annually into the atmosphere than the natural processes can remove each year. For instance, in the 1960s, the global growth rate of atmospheric carbon dioxide was roughly 0.6 ± 0.1 ppm per year, and only half a century later, between 2009-18, the growth rate was 2.3 ppm per year (Blunden & Boyer, 2020). In a period of 60 years, the annual rate of increase is approximately 100 times faster than in previous natural increases, such as at the end of the last ice age 11,000-17,000 years ago.

The burning of fossil fuels has increased carbon dioxide levels from an atmospheric concentration of approximately 280 parts per million (ppm) in pre-industrial times to over 400 ppm in 2018. In other words, since the start of the Industrial Revolution, human activities have led to a 40 % increase in the atmospheric concentration of carbon dioxide. With the current rate of about 2–3 ppm/year, by the end of the 21st century, carbon dioxide concentrations are estimated to exceed 900 ppm.

Suppose this trend of substantially increased carbon dioxide emissions, methane, and other greenhouse gases continues by 2100. In that case, the average surface temperature at the global level could increase by up to 4.8°C compared to pre-industrial levels (Lindsey, 2020). To stop this temperature rise, scientists suggest projects limiting the concentrations and keeping the temperature change as low as possible, preferably below +2°C. The limitations include cuts in anthropogenic greenhouse gas emissions and extensive changes in the energy systems at global levels.     

According to the new International Energy Agency (IEA) analysis, the global energy-related carbon dioxide emissions rose by 6% in 2021, to 36,3 billion tonnes (IEA, 2022). This is the highest ever level, and the main reason for it is the strong rebound of the world economy after the Covid-19 crisis, which mainly relied on coal to power the growth and demand.

• Land use 

Significantly increased land use for agriculture, deforestation and other purposes are accounted for one-quarter of anthropogenic greenhouse gas emissions (IPCC, 2019). The primary sources of emissions are feed production (45 %), greenhouse gas outputs during digestion by cows (39 %), and manure decomposition (10 %). Also, the production and transport of animal products contribute to total greenhouse gas emissions. Moreover, the increased utilization of wetlands and landfill emissions lead to increased methane concentration in the atmosphere.  

• Cement manufacture

Cement is the second most-consumed resource in the world, right behind water. Globally, more than 4 billion tons of material are produced every year. The process of manufacturing cement includes the heating of calcium carbonate, which results in the production of lime and carbon dioxide. As such, this industry is one of the major global emitters of carbon dioxide, emitting approximately 8 % of global carbon monoxide emissions (Lehne & Preston, 2018).

• Aerosols

The burning of fossil fuels has several side effects on the planet, including the small particles suspended in the atmosphere called aerosols. Aerosols can be released from chlorofluorocarbons (CFCs) used in refrigeration systems and halons used in fire suppression systems. Along with the aerosols produced by human activities, several natural processes, including forest fires, volcanoes, and isoprene emitted from plants produce aerosols.

While the greenhouse gases lead to increased temperatures on the Earth’s surface, aerosol pollution can counteract the warming effect. For instance, sulfate aerosols are the product of fossil fuel combustion. This aerosol reduces the amount of sunlight that reaches the Earth’s surface and thus causes a cooling effect.

Benefits of the Greenhouse Effect

While greenhouse gases contribute to global warming, at the same time, they are sustaining life on this planet. Besides regulating the temperature on the Earth’s surface, greenhouse gases offer a myriad of other benefits. Greenhouse gases block the harmful solar radiation from reaching the Earth’s surface. These gases act as a shield that makes the unwanted damaging energy reflect back into space. One of the most important greenhouse gas, ozone, absorbs the Sun’s harmful ultra-violet (UV) rays by 97-99 %. Without the ozone layer, the UV rays would penetrate the Earth’s surface, and long-term exposure to a high level of it can severely damage both animal and plant cells. The greenhouse effect also enables the planet to maintain water levels when it comes to water surfaces.

Sources:

Blunden, J. & Boyer, T. Eds. (2020). State of the climate in 2020. Bull.

Intergovernmental Panel on Climate Change. (2019). Land is a critical resource, IPCC report says. Intergovernmental Panel on Climate Change. Retrieved from: https://www.ipcc.ch/2019/08/08/land-is-a-critical-resource_srccl/.

International Energy Agency. (2022). Global CO2 emissions rebounded to their highest level in history in 2021. International Energy Agency. Retrieved from: https://www.iea.org/news/global-co2-emissions-rebounded-to-their-highest-level-in-history-in-2021.

Lehne, J. & Preston, F. (2018). Making concrete change: Innovation in low-carbon cement and concrete. Chatham House. Retrieved from: https://www.chathamhouse.org/2018/06/making-concrete-change-innovation-low-carbon-cement-and-concrete-0/about-authors.

Lindsey, R. (2020). Climate change: Atmospheric carbon dioxide. National Oceanic and Atmospheric Administration. Retrieved from: https://www.climate.gov/news-features/understanding-climate/climate-change-atmospheric-carbon-dioxide.