Since the end of the last ice age, humans have developed tools and machines and have modified the land for agriculture and long-term settlement. As the population has grown and new technologies have spread across cultures and continents, more and more of the planet’s resources have been pressed into serving the species. In the process, human activities have disrupted the natural order of the environment by depopulating and eliminating species and adding harmful chemicals to the air, water, and soil—activities that are changing the climate and the structure and function of ecosystems, as well as the biological communities they contain. Solving the critical environmental problems of global warming, water scarcity, pollution, and biodiversity loss are perhaps the greatest challenges of the 21st century.
Pollution, also called environmental pollution, the addition of any substance (solid, liquid, or gas) or any form of energy (such as heat, sound, or radioactivity) to the environment at a rate faster than it can be dispersed, diluted, decomposed, recycled, or stored in some harmless form. The major kinds of pollution, usually classified by environment, are air pollution, water pollution, and land pollution. Modern society is also concerned about specific types of pollutants, such as noise pollution, light pollution, and plastic pollution. Pollution of all kinds can have negative effects on the environment and wildlife and often impacts human health and well-being. History of pollution
Although environmental pollution can be caused by natural events such as forest fires and active volcanoes, use of the word pollution generally implies that the contaminants have an anthropogenic source—that is, a source created by human activities. Pollution has accompanied humankind ever since groups of people first congregated and remained for a long time in any one place. Indeed, ancient human settlements are frequently recognized by their wastes—shell mounds and rubble heaps, for instance. Pollution was not a serious problem as long as there was enough space available for each individual or group. However, with the establishment of permanent settlements by great numbers of people, pollution became a problem, and it has remained one ever since.
“By the middle of the 20th century, an awareness of the need to protect air, water, and land environments from pollution had developed among the general public”.
Cities of ancient times were often noxious places, fouled by human wastes and debris. Beginning about 1000 CE, the use of coal for fuel caused considerable air pollution, and the conversion of coal to coke for iron smelting beginning in the 17th century exacerbated the problem. In Europe, from the Middle Ages well into the early modern era, unsanitary urban conditions favoured the outbreak of population-decimating epidemics of disease, from plague to cholera and typhoid fever. Through the 19th century, water and air pollution and the accumulation of solid wastes were largely problems of congested urban areas. But, with the rapid spread of industrialization and the growth of the human population to unprecedented levels, pollution became a universal problem.
By the middle of the 20th century, an awareness of the need to protect air, water, and land environments from pollution had developed among the general public. In particular, the publication in 1962 of Rachel Carson’s book Silent Spring focused attention on environmental damage caused by improper use of pesticides such as DDT and other persistent chemicals that accumulate in the food chain and disrupt the natural balance of ecosystems on a wide scale. In response, major pieces of environmental legislation, such as the Clean Air Act (1970) and the Clean Water Act (1972; United States), were passed in many countries to control and mitigate environmental pollution.
The presence of environmental pollution raises the issue of pollution control. Great efforts are made to limit the release of harmful substances into the environment through air pollution control, wastewater treatment, solid-waste management, hazardous-waste management, and recycling. Unfortunately, attempts at pollution control are often surpassed by the scale of the problem, especially in less-developed countries. Noxious levels of air pollution are common in many large cities, where particulates and gases from transportation, heating, and manufacturing accumulate and linger. The problem of plastic pollution on land and in the oceans has only grown as the use of single-use plastics has burgeoned worldwide. In addition, greenhouse gas emissions, such as methane and carbon dioxide, continue to drive global warming and pose a great threat to biodiversity and public health.
Water scarcity, insufficient freshwater resources to meet the human and environmental demands of a given area. Water scarcity is inextricably linked to human rights, and sufficient access to safe drinking water is a priority for global development. However, given the challenges of population growth, profligate use, growing pollution, and changes in weather patterns due to global warming, many countries and major cities worldwide, both wealthy and poor, faced increasing water scarcity in the 21st century.
In places with low rainfall or limited access to surface water, reliance on aquifers is commonplace. The exploitation of groundwater resources can threaten future water supplies if the rate of withdrawal from the aquifer exceeds the rate of natural recharge. It is estimated that a third of the world’s largest aquifer systems are in distress. In addition, the redirection, overuse, and pollution of rivers and lakes for irrigation, industry, and municipal uses can result in significant environmental harm and the collapse of ecosystems. A classic example of this is the Aral Sea, which was once the world’s fourth largest body of inland water but has shrunk to a fraction of its former size because of the diversion of its inflowing rivers for agricultural irrigation.
As water resources become scarce, there are increasing problems with fair water allocation. Governments may be forced to choose between agricultural, industrial, municipal, or environmental interests, and some groups win at the expense of others. Chronic water scarcity can culminate in forced migration and domestic or regional conflicts, especially in geopolitically fragile areas.
Areas with chronic water scarcity are particularly susceptible to water crises, where water supplies dwindle to critical levels. In 2018, residents of Cape Town, South Africa, were faced with the possibility of “Day Zero,” the day on which municipal taps would run dry, the first potential water crisis of any major city. Thanks to extreme water conservation efforts and the fortuitous arrival of rain, the immediate threat passed without major incident. However, given that humans can survive only a few days without water, a water crisis can rapidly escalate into a complex humanitarian emergency. The 2017 Global Risks Report of the World Economic Forum ranked water crises as the third most important global risk in terms of impact on humanity, following weapons of mass destruction and extreme weather events.
Although the terms global warming and climate change are often used interchangeably, they apply to different phenomena. Climate change refers to changes in Earth's temperature, humidity, air pressure, wind, clouds, and precipitation patterns over time. Global warming is a contributing factor to climate change and refers specifically to the effect of greenhouse gases on Earth's average surface temperature. The term global warming first appeared in geochemist Wallace Broecker's 1975 Science magazine article, "Climatic Change: Are We on the Brink of a Pronounced Global Warming?" Scientists began studying the effect of greenhouse gases on Earth's climate more than a century prior, however, as early as 1820. It was during this time that French scientist Joseph Fourier first discovered that Earth's atmosphere functions to retain the sun's heat. In the early 1900s, Serbian astrophysicist Milutin Milankovitch also identified the long-term climate effects of natural fluctuations in Earth's orbit as well as the tilt and precession of its axis. Since then, scientists and policymakers have worked to better understand the workings of the atmosphere, as well as how to respond to challenges created by climate change.
HOW TO STOP GLOBAL WARMING?
The heat-trapping greenhouse gases are increasing, global temperature is rising, planet is warming, the glaciers are melting and the sea level is rising. This weather change is drastically affecting wildlife and forests. Yes, global warming is happening due to the greenhouse effect. Some of the contributing factors are burning of fossil fuels, deforestation, livestock production and industrialisation. Consequently, it leads to drought, incessant rainfall, hurricanes, extreme heatwaves and other extreme weather conditions. With these adverse effects of global warming happening across the planet, we need to implement ways to stop global warming and protect the planet.
The aim is to cut down the amount of carbon dioxide released in the environment. If you even recycle half of the waste produced at home, you can save up to 2000 pounds of CO2 every year.
Air pollution is one of the major factors that lead to an increase in greenhouse gases. Minimise the use of cars and make use of public transportation. Try walking, biking or carpooling whenever possible. If you reduce the driving hours, you will end up saving one pound of CO2 for every mile.
Deforestation plays an important role in global warming and climatic changes. Planting trees is helpful as they absorb carbon dioxide from the atmosphere and regulate the climate. Hence, there is a dire need to plant more trees because a single tree can absorb one ton of CO2 in its lifetime.
SWITCH TO RENEWABLE ENERGY
One of the most effective ways to prevent global warming is to start using renewable energy sources such as solar, geothermal, wind and biomass, and stop using fossil fuels. Use renewable energy resources to supply power to your home.
USE ENERGY-EFFICIENT DEVICES
By investing in energy-efficient devices such as bulbs, LED lights or solar-powered shower system, you can reduce the energy consumption and help in the production of clean energy. It is not only the cheapest way to reduce greenhouse gas emissions but it also reduces the amount of carbon dioxide released in the atmosphere.
USE LESS HOT WATER
Do you know you can save 500 pounds of CO2 per year if you switch to cold showers and stop using hot water to wash clothes? Try installing energy-efficient geysers that consume less energy.
Biodiversity loss, also called loss of biodiversity, the decrease in the biodiversity within a species, an ecosystem, a given geographic area, or Earth as a whole. Biodiversity, or biological diversity, is a term that refers to the number of genes, species, individual organisms within a given species, and biological communities within a defined geographic area, ranging from the smallest ecosystem to the global biosphere. (A biological community is an interacting group of various species in a common location.) Likewise, biodiversity loss describes the decline in the number, genetic variability, and variety of species, and the biological communities in a given area. This loss in the variety of life can lead to a breakdown in the functioning of the ecosystem where the decline has happened. The idea of biodiversity is most often associated with species richness (the count of species in an area), and thus biodiversity loss is often viewed as species loss from an ecosystem or even the entire biosphere (see also extinction). However, associating biodiversity loss with species loss alone overlooks other subtle phenomena that threaten long-term ecosystem health. Sudden population declines may upset social structures in some species, which may keep surviving males and females from finding mates, which may then produce further population declines. Declines in genetic diversity that accompany rapid falls in population may increase inbreeding (mating between closely related individuals), which could produce a further decline in genetic diversity.Even though a species is not eliminated from the ecosystem or from the biosphere, its niche (the role the species play in the ecosystems it inhabits) diminishes as its numbers fall. If the niches filled by a single species or a group of species are critical to the proper functioning of the ecosystem, a sudden decline in numbers may produce significant changes in the ecosystem’s structure. For example, clearing trees from a forest eliminates the shading, temperature and moisture regulation, animal habitat, and nutrient transport services they provide to the ecosystem.
Researchers have identified five important drivers of biodiversity loss:
1. Habitat loss and degradation—which is any thinning, fragmentation, or destruction of an existing natural habitat—reduces or eliminates the food resources and living space for most species. Species that cannot migrate are often wiped out.
2. Invasive species—which are non-native species that significantly modify or disrupt the ecosystems they colonize—may outcompete native species for food and habitat, which triggers population declines in native species. Invasive species may arrive in new areas through natural migration or through human introduction.
3. Overexploitation—which is the harvesting of game animals, fish, or other organisms beyond the capacity for surviving populations to replace their losses—results in some species being depleted to very low numbers and others being driven to extinction.
4. Pollution—which is the addition of any substance or any form of energy to the environment at a rate faster than it can be dispersed, diluted, decomposed, recycled, or stored in some harmless form—contributes to biodiversity loss by creating health problems in exposed organisms. In some cases, exposure may occur in doses high enough to kill outright or create reproductive problems that threaten the species’s survival.
5. Climate change associated with global warming—which is the modification of Earth’s climate caused by the burning of fossil fuels—is caused by industry and other human activities. Fossil fuel combustion produces greenhouse gases that enhance the atmospheric absorption of infrared radiation (heat energy) and trap the heat, influencing temperature and precipitation patterns.