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Explore the dynamic world of climate change, from ancient ice ages to modern global warming. Learn about ice ages, El Nino, human impact on the climate, and the potential consequences of rising temperatures on our planet's ecosystems, agriculture, and human health.
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Section 4.3 Climates can change suddenly or slowly
vocabulary • ICE AGE: Period in which huge sheets of ice spread out beyond the polar regions. • El NINO: A disturbance of wind patterns and ocean currents in the Pacific Ocean (usually occurs every 3-7 years and lasts for 12 to 18 months).
Particles and cooling • Our atmosphere contains many particles mixed in with the air. Particulates block some of the Sun’s energy, preventing it from reaching Earth’s surface. • Sudden events (like a large volcanic eruption or an impact of rocky objects from space) can cause a large amount of particles to enter the atmosphere and have a drastic cooling effect on global climate.
Mount pinatubo 1991 • Temperatures around the world were affected for about two years.
Continents moving • Pangea to present day…the continents are constantly moving: • Some continental climates cool as they move towards higher latitudes while others warm as they move closer to the equator. • As the continents move, the also alter ocean currents. • Lastly, continental shifts create mountains. This can also have an affect on climate (altering precipitation and prevailing winds . . . Rain shadow)
Repeating climate changes • Generally speaking, a cooler period regularly follows a warmer period each year. The Earth has a natural tendency to repeat cycles and patterns of climate. • Two patterns or cycles include ice ages and el nino. • Ice ages usually last tens of thousands of years. We are living in a warming period. Ice ages are closely linked to changes in how the Earth moves around the Sun and varying amounts of greenhouse gases in the atmosphere (including carbon dioxide) • El Nino can cause unusually dry conditions in the western Pacific region, heavy rainfall in South America, heavier rainfall in the US Southeast, stronger winter storms in CA, and milder temperatures in US northern states.
Human activities • Releasing greenhouse gases has a warming effect on global climate. • Scientists predict that all land areas will warm up by 2100 (rise in global temp. of 1.4*c). • Rise in global temperatures could cause more evaporation (altering precipitation patterns), melt ice sheets covering Earth (affecting ocean currents), and cause higher latitudes to warm. • Global warming could cause the following: • Changes in sea level (rise as ice melts) • Wildlife could die or would be forced to move to different habitats. • Agriculture will be affected by changes in temperature and precipitation (altering food supply) • Human health can be affected (heat related deaths, rise in diseases, such as malaria).