There are a variety of environmental issues that affect the world today. The most common issues tend to be related to the consumption of resources and production of waste, which can result in the destruction of habitats, pollution, and sometimes shortages that may lead to conflict. Other environmental issues include the introduction of non-native species to new areas, where they cause a variety of problems.
Global Warming and Climate Change
The large scale burning of fossil fuels, such as oil, coal, and natural gas has led to possibly the best known, and most serious, of the environmental issues facing mankind today. These fuels are used to generate electricity, to power industrial processes, to provide domestic heating and to drive motorized vehicles and aircraft engines. All of these uses involve the production of carbon dioxide (CO2). Although this gas is not directly harmful to humans or wildlife at the concentrations in which it is found in the air, there is widespread agreement among scientists that it is making the planet warmer by trapping heat in the atmosphere. This has a number of serious consequences.
Evidence suggests that global warming is causing large scale melting of polar ice caps and glaciers in mountainous regions, which, if it continues, will lead to a rise in sea levels. This would potentially result in the loss of large amounts of valuable low-lying agricultural land in coastal areas. Climate change could also lead to drought in some areas, and flooding in others, as patterns of air circulation change. Attempts are underway to tackle the problem by reducing reliance on fossil fuels and investing in alternative energy solutions, such as wind and solar power, but these have met with resistance in some quarters. Other ways of addressing the problem include energy conservation and discouraging the unnecessary use of cars.
Industry, and most forms of transport, release waste products that are harmful to humans, animals, and plants. Examples are sulfur dioxide (SO2), which is released by the burning of coal, and nitrogen oxides, which are produced by internal combustion engines. In the high concentrations that may occur in urban areas, these can harm people directly by causing respiratory problems. They also undergo reactions in the atmosphere that produce acid rain, which can acidify soil and water, affecting plants and aquatic organisms, and damage stone buildings and monuments.
Pollution can also affect water directly, through the discharge of wastewater from industrial processes, agriculture, mining, and domestic activities. Some pollutants may find their way into the sea and accumulate in the food chain. On a more local scale, toxic chemicals from abandoned industrial sites and waste dumps can leave soil contaminated for long periods.
Loss of Habitats
The high demand on land for agriculture, and building to accommodate an increasing population, has led to the destruction of habitats, threatening many animal and plant species with extinction. This has been a particular problem in parts of the Amazon rainforest, where the rapid clearing of trees to create land suitable for agriculture has put a number of species under threat. Similar environmental issues exist in many other tropical rainforest areas, and there is concern that, with the vast diversity of plant life they contain, some plants of medical interest might be lost before they are discovered. The removal of trees also makes land more vulnerable to erosion. Soil can be washed away by the impact of heavy rain that would otherwise have been lessened by the forest canopy, and can dry out through exposure to strong sun, leaving it susceptible to wind erosion.
Shortages of clean, drinkable water are a growing problem in many parts of the world. Rapidly increasing populations in some countries have put a strain on the sewage systems, with many rivers and streams becoming polluted with waste containing dangerous microorganisms. For some people, these rivers and streams may be the only source of water for washing, cooking and drinking. The large-scale use of water for agriculture and industry has depleted groundwater in some regions, and in a number of coastal areas saltwater contamination is a serious problem. Disputes over access to fresh water have led to conflict in some regions.
Many species of plants and animals have been introduced to new areas by humans, sometimes with disastrous consequences. In some cases, these introductions have been deliberate. These would include pets, as well as garden plants that have become naturalized and had an adverse effect on the local wildlife and plant life. In other cases, new species have been brought to an area by accident. Examples are pests and diseases carried by imported plants or exotic animals, and rats brought by ships.