NRC19 - Chapter 19 Climate Control and Ozone Depletion Science Focus Melting Ice in Greenland Largest island 80 composed of glaciers 10 of the worlds

NRC19 - Chapter 19 Climate Control and Ozone Depletion...

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Chapter 19 Climate Control and Ozone Depletion Science Focus: Melting Ice in Greenland Largest island: 80% composed of glaciers 10% of the world’s fresh water Glacial melting and movement accelerating Effect on sea level if melting continues 1 meter rise by 2100 19-1 How Might the Earth’s Temperature and Climate Change in the Future? Concept 19-1 Considerable scientific evidence indicates that the earth’s atmosphere is warming, because of a combination of natural effects and human activities, and that this warming is likely to lead to significant climate disruption during this century. Weather and Climate Are Not the Same Weather is short-term changes Temperature Air pressure Precipitation Wind Climate is average conditions in a particular area over a long period of time Temperature Precipitation Fluctuations are normal Climate Change is Not New (1) Over the past 4.7 billion years the climate has been altered by Volcanic emissions Changes in solar input Movement of the continents Impacts by meteors Changing global air and ocean circulation Over the past 900,000 years Glacial and interglacial periods Climate Change is Not New (2) Over the past 10,000 years Interglacial period Over the past 1,000 years Temperature stable Over the past 100 years Temperature changes; methods of determination Estimated Changes in the Average Global Temperature of the Atmosphere Science: Ice Cores Are Extracted by Drilling Deep Holes in Ancient Glaciers Our Climate, Lives, and Economies Depend on the Natural Greenhouse Effect
Greenhouse gases absorb heat radiated by the earth The gases then emit infrared radiation that warms the atmosphere Without the natural greenhouse effect Cold, uninhabitable earth Human Activities Emit Large Quantities of Greenhouses Gases Since the Industrial Revolution CO 2 , CH 4 , and N 2 O emissions higher Main sources: agriculture, deforestation, and burning of fossil fuels Correlation of rising CO 2 and CH 4 with rising global temperatures Atmospheric Levels of CO 2 and CH 4 , Global Temperatures, and Sea Levels Correlation of CO 2 and Temperature CO 2 Concentrations, 1960-2009 Human Activities Play a Key Role in Recent Atmospheric Warming (1) Intergovernmental Panel on Climate Change (IPCC), with 2010 updates 90–99% likely that lower atmosphere is warming Especially since 1960 Mostly from human-caused increases in greenhouse gases Earth’s climate is now changing from increased greenhouse gases Increased greenhouse gas concentrations will likely trigger significant climate disruption this century Ecological, economic, and social disruptions Human Activities Play a Key Role in Recent Atmospheric Warming (2) Intergovernmental Panel on Climate Change (IPCC), with 2010 updates, cont.

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