How do industrial toxic spills harm the environment? Discuss at least three examples.
Industrial toxic spills can poison wildlife, contaminate soil and water, and damage habitats for a long time. For example, oil spills can coat birds’ feathers and marine mammals’ fur, making it harder for them to stay warm or move, and can harm fish and other sea life. A spill of industrial chemicals into a river can kill aquatic organisms and make the water unsafe for people and animals. Spills of heavy metals such as mercury can persist in sediments and build up in the food chain, harming the growth and reproduction of wildlife and potentially people who eat contaminated fish.
How can the agricultural runoff of fertilizers lead to the destruction of marine habitats?
Rain can wash excess nitrogen and phosphorus from fertilized fields into streams and rivers, which carry the nutrients to the ocean. The extra nutrients can cause algal blooms that block sunlight from reaching seagrasses and other underwater plants. When the algae die, bacteria decompose them and use up dissolved oxygen, creating hypoxic areas or “dead zones” where many fish and other organisms cannot survive. Some blooms also release toxins, further harming marine life and disrupting food webs and habitats.
Not all scientists agree with commonly held views on global warming. Describe at least three issues on which there is some disagreement.
Scientists overwhelmingly agree that Earth is warming and that human greenhouse-gas emissions are the main cause of recent warming. There is some disagreement and uncertainty about details. For example, estimates differ about how much warming will occur under different future emissions pathways and how quickly it will happen. Scientists also study how strongly particular regions will be affected, since rainfall, drought, and temperature changes will vary by place. There is further uncertainty about the exact timing and scale of effects such as sea-level rise and changes in particular extreme weather events. These debates concern details and projections rather than the basic conclusion that human activity is warming the climate.
According to the majority of scientists, which of the following occurrences is most responsible for recent increases in global temperatures?
Which of the following is considered to be part of the biosphere?
Acid rain __________.
Beijing, China and Mumbai, India have both been singled out by environmentalists for their __________.
According to many scientists, what effect does pollution have on global temperatures?
What are some of the benefits humans receive from altering their environment? Write your answer in a paragraph of at least five sentences.
Humans alter the environment to grow crops and raise livestock, which provides food for communities. We build homes and towns to provide shelter and places to work. Roads, bridges, and ports make it easier to travel and transport goods. Dams and reservoirs can store water, help control floods, and generate electricity. We also develop land and natural resources to create jobs and produce materials people use every day. These changes can improve living standards, although they may also have environmental costs.
When humans clear forested land, they gain something, but they also harm the natural environment. Explain the trade-off that is occurs.
When people clear forests, they gain land for farming, grazing, homes, roads, or businesses, and they may also obtain timber and jobs. The trade-off is that clearing destroys and fragments wildlife habitat, which can reduce biodiversity and threaten species. With fewer trees, soil is more exposed to erosion and less able to retain water. Cutting or burning forests also releases stored carbon and reduces the forest’s ability to absorb carbon dioxide. People gain useful land and resources, but the natural environment loses important habitats and ecosystem functions.
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