9.3+Climate+and+Climate+change.pptx

HMH Science Dimensions Earth and Space Science Unit 9: The The Atmosphere Lesson 3: Climate and Climate Change Unit 9 Lesson 3 Can You Explain It? Arctic Sea Ice Cover. 1984; 2016 2 What could be the cause of the gradual decrease in sea ice coverage and thickness in the Arctic? What effects cou...

HMH Science Dimensions Earth and Space Science Unit 9: The The Atmosphere Lesson 3: Climate and Climate Change Unit 9 Lesson 3 Can You Explain It? Arctic Sea Ice Cover. 1984; 2016 2 What could be the cause of the gradual decrease in sea ice coverage and thickness in the Arctic? What effects could this change have on the land and sea in the Arctic, the ecosystems in the Arctic, or even on the rest of the globe? Unit 9 Lesson 3 Climate • Earth appears to have a climate that can be described as mild, or temperate. • At any given location on Earth, you are unlikely to find The coast of Yemen in the Middle these average conditions. East. • The differences in ecosystems from place to place on Earth are heavily influenced by the regional climate factors, including average humidity, cloud cover, wind speed, The Congo River Basin in the DRC. temperature, and precipitation. 3 Unit 9 Lesson 3 Climate • Weather is defined as the current state of the atmosphere. • Climate is the average weather patterns over a long period of time. • Regional climates can be classified as: • Tropical Climates can be classified based on temperature and rainfall. Explore four • Dry different biomes characteristic of • Temperate different climates. • Continental • Polar 4 Unit 9 Lesson 3 Climate • In general, hot climates are found near the equator, very cold climates are found near the poles, and temperate climates are in the midlatitudes. • The global wind systems also influence climate. Earth on the June solstice 5 • Because land and water heat up and cool down at different rates, climates near large bodies of water may be very different from those inland. Unit 9 Lesson 3 Climate • Regions at high elevation tend to have cooler climates than those at low elevation. This effect occurs because air temperature decreases with altitude. The climate of the Sierra Nevada is cooler than areas at lower elevation. 6 • Mountains can also affect climate by redirecting air currents by channeling or blocking winds. • Precipitation patterns Unit 9 Lesson 3 Climate ANALYZE Use the Sioux Falls climate graph to address the following items: 1. Write a brief description of the climate of Sioux Falls based on the information in the graph. 2. Describe the relationship between temperature and precipitation in Sioux Falls. 3. Can you tell from the climate graph what the weather would be like in Sioux Falls on July 4 of this coming year? Explain your answer. 7 4. Using the climate Unit 9 Lesson 3 Earth’s Changing Climate • Climate change is a change in Earth’s climates, usually due to a change in Earth’s energy. Scientists remove an ice core from a core barrel in Antarctica. 8 • Some of the most useful tools for studying how global climate has changed are cores of ice from Greenland and Antarctica. • Ice cores provide a record of climate going Unit 9 Lesson 3 Earth’s Changing Climate Volcanic eruption of Kilauea in Hawaii. 9 • Earth’s climate changes on different scales of space and time. It can change slowly, over the course of millions of years, or almost instantly, over the course of a few days. • Climate change can involve a small portion of Earth’s surface or the entire globe. • Volcanoes give off some carbon dioxide and water vapor into the atmosphere, but the overall effect of volcanic activity is to cool Unit 9 Lesson 3 Earth’s Changing Climate Causes of Climate Change • Volcanism • Orbital Changes • Plate Tectonics • Changes in Atmospheric Composition • Earth’s global climate changes for various reasons and on many different scales of time. It EXPLAIN changes over millions of years. Compare the different causes of climate change and the timescales over which they affect Earth’s climate. 10 Instruments on NASA’s Terra satellite measure amounts of thermal radiation and sunlight. Unit 9 Lesson 3 Our Role in Climate Change • The model here shows that global temperatures are currently rising much faster than they would if climate were influenced only by natural factors. • Most scientists have concluded that the current increase in average global temperature is primarily a result of human activities. 11 Unit 9 Lesson 3 Our Role in Climate Change This graph represents data collected from ice cores that show how carbon dioxide levels in the atmosphere have changed over the past 800 000 years as compared to the current increase. 12 Unit 9 Lesson 3 Our Role in Climate Change • The most obvious effect of global climate change is an increase in average annual global surface temperature. Rising sea levels affect the coastlines. 13 • With an increase in temperature, evaporation rates increase, changing precipitation patterns. • Current climate change models suggest that sea level could rise another 1 Unit 9 Lesson 3 Our Role in Climate Change • A major cause of sealevel rise today is the addition of water to the oceans as glaciers and ice sheets melt. As sea ice melts, Earth becomes less reflective and absorbs more solar energy. 14 • However, even when no water is being added to oceans through melting, increasing temperature causes sea levels to rise. This happens because water expands as it Unit 9 Lesson 3 Our Role in Climate Change Stability and Change • Feedback is a situation in which cause and effect are intertwined. Part of the output (the effect) becomes new input (cause). • Positive feedback tends to destabilize a system. • Negative feedback helps keep systems stable. An important example of negative feedback related to climate has to do with plant growth: An increase in carbon dioxide in the atmosphere can lead to an increase in plant growth, which removes carbon dioxide from the atmosphere. 15 Unit 9 Lesson 3 Our Role in Climate Change A solar panel array in Nevada generates electrical energy from sunlight. • Nearly 10 gigatons of carbon are released into the atmosphere each year through human activities. Only about half of that is taken up by plants or absorbed by the oceans. • There are several things that scientists, engineers, and individual citizens can do to mitigate the problem: • Refine our energy production Replace traditional incandescent • Increase efficiency lightbulbs with compact fluorescent. • Remove carbon from the 16