Human Impact on the planet

How do greenhouse gases cause global warming?

• A. They absorb heat radiated from Earth’s surface.

• B. They reflect solar energy from Earth’s exosphere.

• C. They produce smog, which traps thermal energy near the ground.

• D. They damage the ozone layer, allowing more solar energy to enter the atmosphere.

Answer explanation

Some gases in the Earth's atmosphere act a bit like the glass in a greenhouse, trapping the sun's heat and stopping it from leaking back into space and causing global warming by radiating the heat.

Consider the following sequence of events: Human beings discover a way to remove CO from the atmosphere. Using this process, we remove half of the CO from the atmosphere. Many plants grow slower, slowing down the rate of photosynthesis. CO levels begin to rise. This is an example of a ___________.

• Positive

• Negative

Acid rain has become a pressing problem in Maryland where fishing is a way of life, and an integral part of the economy. Controlling acid rain is especially important in Maryland restoration and preservation of the Chesapeake Bay. Evidence that acid rain negatively affected the Chesapeake Bay ecosystem is that ______.

• A. rain has increased the amount of water in lakes and streams in the area

• B. there has been a decrease in the variety of fish found in the Chesapeake Bay

• C. the amount of carbon dioxide in the air over the Maryland has drastically decreased in recent years

• D. the number of heterotrophic organisms in lakes and streams has increased

An invasive species, the spiny water flea, was recently found in a Maryland lake. These water fleas eat zooplankton, a food also consumed by native fishes. The fleas spread from lake to lake by attaching to fishing lines, anchor ropes, and boats. Which statement best describes the effect of the water flea on the lake?

• A. It will not compete with animals in the local food chain.

• B. It will not compete with animals in the local food chain. B. It will feed on organisms that are important to other species.

• C. The number of water fleas will decrease due to a lack of food. e

• D. There will be no effect on native species in the lake.

Which greenhouse gases are correctly paired with their sources? Choose all that apply

• Carbon Dioxide from burning fossil fuels & Chlorofluorocarbons - air conditioners, refrigerators and insulation

• Nitrogen gas

• Nitrous oxide

• Methane gas

The recent increase in global warming

• Planting trees

• Volcanic Eruption

• Cell Respiraton

• Burning fossil fuels

Answer explanation

When humans burn fossil fuels for energy, carbon dioxide are released back into the atmosphere. This excessive carbon dioxide changes our climate — increasing global temperatures, causing ocean acidification, and disrupting the planet's ecosystems.

Which is the strongest evidence for climate change?

• A. A colder-than-average winter.

• B. A warmer-than-average summer.

• C. A pattern of major blizzards affecting several cities in a particular winter.

• D. A pattern of increasing frequency and intensity of storms over many years.

Answer explanation

Temperatures are rising world-wide due to greenhouse gases trapping more heat in the atmosphere. Droughts are becoming longer and more extreme around the world. Tropical storms becoming more severe due to warmer ocean water temperatures.

ꞏ The “Half 1990 emissions” line shows CO levels if emissions are cut to half of the level that they were in 1990.

Which statement is supported by the graph?

• A. Climate change will result in the melting of polar ice caps.

• B. The increase in carbon dioxide levels will cause a decrease in global average temperature.

• C. Human activities have no effect on atmospheric carbon dioxide levels.

• D. Future generations can be affected by the choices of current generations.

Why is the runoff from fertilized agricultural fields often harmful to the ecosystems of lakes?

• The fertilizer promotes the growth of fish to the point where they cannot find enough food to eat.

• B. The runoff causes surface algal bloom which decreases the penetration of light into the water which decreases photosynthesis which reduces the amount of oxygen in the

• C. Fertilizer runoff promotes antibiotic resistance

• D. The runoff raises the levels of inorganic nutrients in the surface waters to levels that are toxic to algae and other lake organisms.

Answer explanation

Algal blooms can be dramatic and are a result of excess nutrients from fertilizer, wastewater and stormwater runoff, coinciding with lots of sunlight, warm temperatures and shallow, slow-flowing water.