Environmental Science: Climate Change: Evidence and Impacts
Examining data, causes, and effects of a warming planet
Environmental Science: Climate Change: Evidence and Impacts
Examining data, causes, and effects of a warming planet
Environmental Science - Grade 6-8
- 1
Define climate change in your own words. Explain how climate is different from weather.
Think about the difference between today's temperature and the average temperature over 30 years.
Climate change is a long-term change in Earth's average weather patterns, such as temperature, rainfall, and storm patterns. Weather describes short-term conditions on a particular day, while climate describes patterns over many years. - 2
A graph shows that global average temperature has increased over the last 100 years. Explain why a long-term temperature graph is stronger evidence for climate change than one unusually hot day.
A long-term temperature graph is stronger evidence because it shows a pattern over many years. One hot day can happen because of normal weather variation, but a steady warming trend over decades shows a change in climate. - 3
Scientists study ice cores from glaciers and ice sheets. What information can ice cores provide about past climates?
Think about what might be trapped inside layers of ancient ice.
Ice cores can provide information about past temperatures, snowfall, and the gases in Earth's atmosphere long ago. Tiny air bubbles trapped in the ice can show past levels of carbon dioxide and other greenhouse gases. - 4
Carbon dioxide levels in the atmosphere were about 280 parts per million before the Industrial Revolution and are now about 420 parts per million. How much have carbon dioxide levels increased?
Subtract the earlier amount from the current amount.
Carbon dioxide levels have increased by 140 parts per million because 420 minus 280 equals 140. - 5
Explain how burning fossil fuels can lead to global warming.
Burning fossil fuels releases carbon dioxide into the atmosphere. Carbon dioxide is a greenhouse gas that traps heat, so adding more of it can increase Earth's average temperature. - 6
Look at a diagram of the greenhouse effect. Describe the role greenhouse gases play in Earth's atmosphere.
Focus on sunlight coming in and heat being held near Earth.
Greenhouse gases allow sunlight to enter the atmosphere but trap some heat that Earth gives off. This natural effect keeps Earth warm enough for life, but extra greenhouse gases can trap too much heat and cause warming. - 7
Name two types of evidence scientists use to show that Earth's climate is warming, and explain what each one shows.
One type of evidence is temperature records, which show that average global temperatures have risen. Another type of evidence is shrinking glaciers, which show that many places are warm enough to melt ice faster than it is replaced. - 8
A glacier has been photographed every 10 years since 1970. The photos show the glacier becoming smaller each decade. What does this evidence suggest, and why should scientists compare it with other data?
One kind of evidence is helpful, but several kinds together make a stronger explanation.
The photos suggest that the glacier is shrinking, which can be evidence of warming conditions. Scientists should compare it with other data, such as temperature and snowfall records, to understand whether climate change is the main cause. - 9
Sea level can rise when land ice melts and when ocean water warms. Explain both processes.
Sea level rises when glaciers and ice sheets on land melt and add water to the ocean. Sea level also rises because warmer ocean water expands and takes up more space. - 10
A coastal town has noticed more frequent flooding during high tides. Explain how climate change could make this problem worse.
Think about what happens when the base level of the ocean becomes higher.
Climate change can make high-tide flooding worse by raising sea level. When the ocean starts from a higher level, tides and storms can push water farther onto land. - 11
How can climate change affect animal and plant habitats? Give one specific example.
Climate change can affect habitats by changing temperature, rainfall, and the timing of seasons. For example, a cold-adapted animal may have to move farther north or to higher elevations as its habitat becomes warmer. - 12
The table shows the average spring arrival date of a bird species in one region. In 1980, it arrived on April 20. In 2020, it arrived on April 8. What pattern does this show, and how could it be connected to climate change?
Compare the dates and decide whether the event is happening earlier or later.
The pattern shows that the birds are arriving earlier in spring. This could be connected to climate change because warmer spring temperatures can cause migration, flowering, and insect activity to happen earlier. - 13
Describe one way climate change can affect human health.
Climate change can affect human health by increasing heat waves, which can cause heat exhaustion and heat stroke. It can also worsen air quality or expand the range of some disease-carrying insects. - 14
A region usually receives steady rainfall, but recent years have brought longer droughts. Explain how drought can affect people, farming, and ecosystems.
Consider water needs for homes, farms, and natural habitats.
Drought can reduce the water available for drinking, crops, and livestock. It can also dry out soils, stress plants and animals, reduce crop yields, and increase the risk of wildfires. - 15
A student says, "The climate has changed naturally before, so humans cannot be causing today's climate change." Write a response that uses evidence and scientific reasoning.
A good response can accept that natural changes happen while explaining why current evidence points to humans.
Earth's climate has changed naturally in the past, but today's rapid warming matches the sharp rise in greenhouse gases from human activities such as burning fossil fuels. Scientists compare natural causes, human causes, and many types of data, and the evidence shows that human activities are the main cause of recent warming.