HIE - Effects of Human Growth on Earth Lesson

 

Effects of Human Growth on Earth

Along with the increases in food that have come from the Green Revolution have come enormous impacts on the planet. More food has allowed the human population to explode. Natural landscapes have been altered to create farmland and cities. Already, half of the ice-free lands have been converted to human uses. Estimates are that by 2030, that number will be more than 70%.

Forests and other landscapes have been cleared for farming or urban areas. Rivers have been dammed and the water is transported by canals for irrigation and domestic uses away from the source. Ecologically sensitive areas have been altered: wetlands are now drained and coastlines are developed.

Modern agricultural practices produce a lot of pollution. Some pesticides are toxic. Fertilizers drain off farmland and introduce nutrients into lakes and coastal areas, causing fish to die. Farm machines and vehicles used to transport crops produce air pollutants. Pollutants enter the air, water, or are spilled onto the land. Moreover, many types of pollution easily move between air, water, and land. As a result, no location or organism—not even polar bears in the remote Arctic—is free from pollution.

The increased number of people have other impacts on the planet. Humans do not just need food. They also need clean water, secure shelter, and a safe place for their wastes. These needs are met to different degrees in different nations and among different socioeconomic classes of people. For example, about 1.2 billion of the world's people do not have enough clean water for drinking and washing each day.

A large percentage of people expect much more than to have their basic needs met. For about one-quarter of people, there is an abundance of food, plenty of water, and a secure home. Comfortable temperatures are made possible by heating and cooling systems, rapid transportation is available by motor vehicles or a well developed public transportation system, instant communication takes place by phones and email, and many other luxuries are available that were not even dreamed of only a few decades ago. All of these need resources to produce and fossil fuels to power. Their production, use and disposal all produce wastes. Many people refer to the abundance of luxury items in these people's lives as over-consumption. People in developed nations use 32 times more resources than people in the developing countries of the world.

There are many problems worldwide that result from overpopulation and over-consumption. One such problem is the advance of farms and cities into wild lands, which diminishes the habitat of many organisms. In addition, water also must be transported for irrigation and domestic uses. This means building dams on rivers or drilling wells to pump groundwater.

Large numbers of people living together need effective sanitation systems. Many developing countries do not have the resources to provide all of their citizens with clean water. It is not uncommon for some of these children to die of diseases related to poor sanitation. Improving sanitation in many different areas - sewers, landfills, and safe food handling - are important to prevent disease from spreading.

Wildlife is threatened by fishing, hunting and trading as population increases. Besides losing their habitat as land is transformed, organisms are threatened by hunting and fishing as the human population grows. Hunting is highly regulated in developed nations, but many developing nations are losing many native animals due to hunting. Wild fish are being caught at too high a rate and many ocean fish stocks are in peril.

Humans also cause problems with ecosystems when they introduce species that do not belong in a habitat. Invasive species are sometimes introduced purposefully, but often they arrive by accident like rats on a ship. Invasive species often have major impacts in their new environments. A sad example is the Australian Brown Tree Snake that has wiped out 9 of the 13 native species on the island of Guam.

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