Human Impacts on the Environment Environmental Science

Pollution–any environmental contaminant that causes damage or harm water air land

Types of pollutants Chemical– car exhaust, oil, smoke stacks, pesticides Solid– litter, trash, soot, plastic Biological– sewage, decaying material Thermal– excess heat in an aquatic habitat harms the ecosystem Radiation– radioactive waste

Effects Overuse/misuse of resources Encroachment on natural habitats Increased pollution Failed infrastructure Overpopulation One major cause is lack of education. Earth’s human population in 2013– 7 billion Estimated carrying capacity 4-16 billion

Deforestation Approximately 18 million acres are lost each year Reasons timber harvest commercial or residential development create farmland Effects loss of biodiversity loss of rare or currently unknown species increased erosion Increased carbon dioxide in atmosphere

Desertification Drought is a natural cause Humans contribute by allowing overgrazing and irresponsible farming Erosion by wind and water are the most significant effects

Biodiversity– the number and variety of species in an ecosystem Biodiverse ecosystems are healthier Anything that threatens biodiversity, causing species to become threatened, endangered, or extinct, weakens the ecosystem.

Threatened Species The species’ numbers are in decline, and the species is likely to become endangered.

Endangered species The numbers are so low that the species is likely to become extinct without immediate protective measures

Extinction– if a species has not been present in 50 years Dodo Stephen’s Island wren Chinese river dolphin Root-spine palm

Biodiversity Humans benefit from biodiversity through Medicines Agriculture Industry How many species have become extinct before they were even discovered? How much biodiversity has been lost, while still unknown? Ecosystems are interconnected in many ways (it’s not always obvious) Biodiversity increases sustainability

Modern impact of humans on environment began during the industrial revolution Drastic increase in use of fossil fuels (coal, oil, natural gas) Land damage from mining those fossil fuels Rapid urbanization (led to pollution, waste, lack of infrastructure, diseases) 200+ years of pollution (air, land, and water) Extreme increase in greenhouse gas emissions

Individuals can evaluate their own carbon footprint– a measure (in pounds) of each person, group, or company’s emissions of greenhouse gases Anything that uses electricity– heating/cooling, household lighting, electronics Using your car Waste products

Conservation & Sustainability Individual or group efforts to preserve or protect the environment– biodiversity & natural resources Prevent pollution Recycling Reduce carbon footprint Limit consumption Limit waste Reduce use of fossil fuels

Partial History of Environmentalism in the US Early 1900s– Theodore Roosevelt enacted the American Antiquities Act (established National Parks & other preserved wildlife areas) 1936– National Wildlife Federation founded 1962—Rachel Carson publishes Silent Spring 1963– Clean Air Act 1965– Water Quality Act 1970– First Earth Day Clean Water Act 1980– Superfund 1990-National Environmental Education Act 2001– U.S. rejects Kyoto Protocol (emissions control)

Climate change– the big debate Are atmospheric carbon dioxide levels rising? Is Earth’s average temperature increasing enough to cause a difference? Is this a naturally-occurring phenomenon? Is this a catastrophe that humans have caused?

Effects of climate change Shrinking glaciers Loss of sea ice Rising sea level Longer, more severe heat waves & droughts Increased risk of fires & floods Stronger storms Change in weather patterns