A History of Global Climate Change

Explain why entering an interglacial period resulted in an increase in biodiversity on Earth.

During an ice age the conditions on Earth favor glaciers and cold deserts over more hospitable environments. Therefore, when the ice age ended and glaciers retreated the more hospitable grasslands and forests that developed hosted greater biodiversity.

Explain why scientists are concerned about human activities that cause global warming if global warming is caused by the greenhouse effect and the greenhouse effect is a natural part of Earth's climate.

Even if global warming is a natural part of Earth's climate, human activities are accelerating it. Global temperatures are expected to rise much faster than they would have naturally, which may result in severe environmental and climate changes across the globe. These predicted impacts of global warming could have severe, negative impacts to humans.

Explain why some groups doubt the occurrence of global warming and global climate change.

Some groups point out that water is a more significant contributor to warming in the atmosphere. Therefore, they argue that carbon dioxide is not a significant greenhouse gas so any observed warming is not the result of human activity. To many of these groups any discussion of global warming or climate change is a form of media alarmism.

Explain how glaciers can change the landscape and physical characteristics of continents.

The advancing front of a glacier acts like a bulldozer, scraping across the landscape and carving out new features. This can carve out new courses for rivers and lakes and flatten out landscapes.

Explain why the greenhouse effect is not entirely a man-made phenomenon.

While many human activities produce greenhouse gases, the greenhouse effect is actually a natural process. Many atmospheric gases help trap heat in Earth's atmosphere, including natural gases like carbon dioxide. So while human activities exacerbate the natural greenhouse effect, it is not solely due to them.

Which of the following continents was covered by glaciers during the Pleistocene ice age?

a. Europe

Why did scientists think the world was experiencing global cooling between the 1940's and 1970's.

a. Pollution was blocking sunlight.

Human activities _______.

a. exacerbate the natural greenhouse effect

Without the greenhouse effect, Earth would be _______.

a. too cold to support our current ecosystem

Which of the following best describes the impact of glaciers upon the surface of the earth?

b. Glaciers scraped across the surface and altered landscapes and the course of rivers.

Many scientists expect global temperatures to _______ by 2100.

b. rise 1.4-5.8ºC

Which of the following continents was not covered by ice during the Pleistocene ice age?

c. Australia

Which of the following best explains why air pollution that was once blamed for global cooling is now considered responsible for global warming?

c. Scientists mistakenly thought pollution reflected sunlight and heat rather than absorbed it.

Which of the following is not a manmade cause of global warming?

c. respiration

"In a 2009 study, presented by the National Academy of Science, 97% of climate scientists agree that human activity is causing global warming." Which of the following statements is best supported by this study?

d. Most climate scientists believe that there is evidence that explains global warming.

Which of the following is predicted to be an impact of global warming?

d. all of the above

Greenhouse gases are best described as _______.

d. gases that trap energy from the sun in Earth's atmosphere

Which of the following is not true concerning the interglacial period that began 15,000 years ago?

d. none of the above

Africa was covered by glaciers during the Pleistocene ice age.

false

Greenhouse gases are essential to support life on earth.

true