Topic 10 – Ecological Concepts Summary Part 3Human Impacts on the Environment

The human population needs many resources from our environment. From fossil fuels to food and water, to rare earth metals.

Humans are the one species on Earth that our existence effects all other species on the Earth.

Humans are no exception we can not survive on our own without other living things.

Human Population Growth : Today humans have very few checks on our population from Nature. With our technology we are living longer, with better nutrition, than any other time in our existence.

The human population is using resources from the Earth at the fastest rate in history, but the resources are FINITE. (Limited)

Habitat Destruction by humans is the number cause of species extinction today !

Deforestation and Destruction of the Rainforests

-Thousands of unknown plant and animal species that may be useful are lost.Medicines, food etc.

Human population in 2020 is 7.8 Billion

Disease, Starvation, and Natural Disasters are the main natural checks on our population

Mining and Mineral Extraction

Also causes pollution from runoff and erosion

Building cities and towns.

Turning nature into steel and concrete jungles.

Clearing forests and natural grasslands to grow crops and raise livestock for our food.Tremendous loss of BIODIVERSITY and also causes pollution from fertilizers,

pesticides, erosion, and animal wastes.

Renewable Resources : A natural resource which will replenish to replace the portion depleted by usage and consumption, either through natural reproduction or other recurring processes in a finite amount of time in a human time scale. (Weeks, Years, or Decades)Examples: Trees, Air, Water, Sunlight, Living Things

Non-Renewable Resources : A natural resource which will NOT replenish to replace the portion depleted by usage and consumption within human time scales. (Thousands to millions of years to never) ONCE THEY ARE GONE THEY ARE GONE!Examples: Fossil fuels (Coal, Oil, Gas), Minerals such as metals and nonmetals

Since the industrial Revolution, human’s main source of energy has been FOSSIL FUELS. These fuels are nonrenewable and cause lots of POLLUTION.

Another important source of energy is THERMO-NUCLEAR: This form also causes huge environmental hazards such as Meltdown and radiation leaks and storage of DANGEROUS nuclear wastes.

Renewable Energy (Alternative Energy): Energy that uses renewable sources such as:

Solar Power – Sunlight Water – Hydroelectric Biofuels – Making fuel from plant sources such as Ethanol Geothermal – Heat from the earth.

Pollution and the Environment: Humans cause a tremendous amount of pollution that harms the environment including ourselves and other living things.

Examples: Smoke and Particulates that go into the air from burning fossil fuels. Sewage Wastes flowing into our rivers, streams and groundwater. Garbage and Landfills Chemicals from Industrial and Household Wastes Plastics – Humans produce a huge amount of plastics that most end up in our

water ways and oceans. We produce 80 million tons of plastic pollution/ year! The list goes on and on…

REDUCE, REUSE, RECYCLE….

Pesticides, Insecticides and Herbicides: Chemicals humans use in the environment to kill unwanted plants and animals. Mainly for agriculture.

Many times these chemicals affect more than the organisms we are trying to get rid of. They get into our water ways, air and soils. Also, organism become RESISTANT and they don’t work as well, so we use more or more powerful chemicals.

Examples: DDT and killing of bald eagles

Global Pollution Problems:

Ozone Depletion:

In Earth’s atmosphere there is a layer of OZONE gas that protects life from harmful ULTRAVIOLET (UV) rays from the sun. Human pollution from aerosol sprays, refrigerants and Styrofoam’s called Chlorofluorocarbons (CFCs) break down the ozone causing holes that allow more UV rays to strike the earth’s surface. UV rays cause skin cancer in humans and other mammals.

Blue color shows areas with little to no ozone.

Acid Rain: Pollution from the burning of fossil fuels especially coal in the form of Sulphur dioxide (SO2) or nitrous oxide (NO2) combine with water in clouds to form acidic rain. The acid rain then kills plants and aquatic life.

Global Warming and CLIMATE CHANGE:

One of the greatest environmental problems our planet faces today is Climate Change.

The Earth’s atmosphere has a natural system to keep Earth’s temperature in balance and make our planet habitable by life. Part of this system is called the Greenhouse Effect.

The Greenhouse Effect involves gases in our atmosphere such as Water Vapor, Carbon Dioxide and Methane. (Greenhouse Gases). The GREENHOUSE EFFECT is a VERY GOOD THING!

Steps to Greenhouse Effect:1. Most of the energy coming from the Sun is in the form of rays of light. The light

can pass through our atmosphere to the surface.2. Once the light strikes the surface the Earth reflects some but ABSORBS most of

the energy. 3. The Absorbed energy is then given off the surface as HEAT into the AIR.4. There are naturally lower levels of the above Greenhouse Gases such as CO2

that will absorb and re-radiate the heat back towards the surface keeping Earth’s surface warmer. (Like a blanket in your bed reflecting your body heat back to you keeping you warm at night.)

Global Warming and Climate ChangeIn past few hundred years, due to industrialization, humans have increased the amounts of Greenhouse Gases ABOVE NORMAL. Mostly by burning FOSSIL FUELS. This increases the amount of CO2 and other GHGs in the air causing the natural greenhouse effect to be amplified making the Earth warmer than normal.

Carbon Dioxide Levels Have Dramatically Increased in the Air

Earth’s Temperature has also Increased due to increased CO2

Some Effects of Climate Change:

Rising Sea Levels: This is due to 2 factors. The first is the melting ice caps of Greenland and Antarctica. The second accounts for most of the Sea Level rise and that is THERMAL EXPANSION of the water itself. When water and substances warm they expand taking up a greater volume.

o As sea level rises much of the world’s coastlines will be under water. o Hundreds of millions of people live along the world’s coast. Just in

America; New York City, Miami, Los Angeles, Chicago, Buffalo, Cleveland, Philadelphia are just some of the cities that will be underwater.

o Some of the Largest cities in the world are also on the coast; Hong Kong, Tokyo, Sydney, Rio in Brazil, London, etc.

More Severe Weather Events: Larger storms such as hurricanes, tornadoes and thunderstorms. Causing damage and flooding.

o Also drought and desertification, many places are becoming drier and drier that were once fertile.

o These factors affect crops and food production as well as loss of life.o Also makes Wild Fires to be more frequent and larger

Changing Wind and Ocean Currents: The wind directions are a major factor in our daily weather. The ocean currents and winds are extremely important to life and moving heat around the Earth.

Acidification of the Ocean Water : Carbon Dioxide can easily dissolve from the atmosphere into the water at the surface. The CO2 in the Air, the more CO2 that dissolves in the water. The more CO2 in the water the more acidic the water becomes. The changes in water temperature and pH greatly affects ocean ecosystems. Remember living things can only live best if the limiting factors are in their optimal range. Example: Coral Reef Bleaching.