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Chapter 11.1 Natural Causes of Climate Change Climate __________________________________________________________ is the average conditions in the atmosphere in a large region over ___________________________________. (clouds, precipitation, temperature, 30 or more years humidity, atmospheric pressure, Solar radiation, wind) BC has a range of climate zones. Biogeoclimatic zone is a region with specific types of plants, soil, geography, _____________________________ and climate ______________. BC has 14 different Biogeoclimatic zones. Paleoclimatologists: Study past climate conditions in order to better understand future climate conditions. Plant fossils, Ice core samples, tree rings. BC has experienced many changes in climate 21000 years ago a large part of Canada was buried under 2km of ice. By looking at Ice core samples paleoclimatologists are able to analyze the ___________________________ the composition of the __________________________________________ atmosphere over the last 650 000 years. earths tilt Many factors affect climate: composition of the earths atmosphere, ____________, rotation and _______ orbit water cycle ______________, ocean currents _______ around the sun, _____________, carbon cycle and ___________________. catastrophic events. _____________ Natural Green house effect: absorption Of thermal energy by the atmosphere gases absorb and emit Green house _____________________ energy as thermal radiation. _________________________________. The earths tilt and orbit causes the earth to experience distinct seasons It affects the angle of incidence of sun light. ____________________________________. The earths tilt varies between 22.1o and 24.5o every 41000 years. The earth’s rotation has a wobble of about ___________________________ 12000 years. ______________________ This also affects the angle of _________________________________. Incidence of the sun’s rays The earths orbit around the sun also changes Over 100000 years causing the earth to ___________________________________. orbit farther away from the sun It is believed that these factors have caused Ice ages to occur in the past. Concept Check p. 465-470 1. What is a biogeoclimatic zone 2. How has the climate in Canada changed since 21, 000 years ago? 3. Name one method paleoclimatologists used to determine how much CO2 was in the atmosphere in the past 4. What is the greenhouse effect? 5. How does earth's tilt affect the amount of solar radiation that reaches us? 6. What is the shape of Earth’s orbit around the Sun? The Water Cycle: The circulation of water _________________ on, above and below the Earth’s surface. Water vapour H2O is the most abundant greenhouse gas in the atmosphere. ________________ High temperatures increase the evaporation of water and the amount of water vapour that air can hold. Ocean Currents: Convection currents in the ocean ___________________ transport large amounts of ________ heat ________________ around the earth. and water Deep ocean currents (below 500 m) and Surface currents are connected to global climate _______________________. density These currents are driven by _______ differences Density is affect salinity __________. and temperature. Salty and cold water are more dense. As ice forms it makes water saltier as it melts it makes water less salty. warm temperatures cause evaporation which makes water saltier. precipitation makes water less salty. ______________ Surface currents exchange heat with the atmosphere affecting weather and climate. Thermocline a transition zone that separates the deep cold water from the warm surface water. deflects water as well as wind to the right The Coriolis affect ________________________________________ in the northern left hemisphere and to the ______________ in the southern hemisphere. (El Nino-Southern Oscillatioin ENSO) El Nino warm When surface waters become ________ off the coast of Ecuador and Peru. this results in mild warm weather on the Coast of BC and eastern Canada. La Nina Cool surface waters cause unusually ________________ Warm weather in southeast region of North America and unusually cold in the northwest. Remember The Carbon Cycle Catastrophic Events: Large scale disasters have happened many times in Earth’s history. sunlight Large volcanic eruptions: can block out _____________. Release large amounts of sulfur dioxide sulfuric acid _________ (SO2) into the atmosphere forming ________________ (H2SO4). These stratosphere reflecting large amounts of sunlight back into space. droplets travel in the _________ The Tambora Eruption in 1815 in Indonesia lead to the Year without Summer in Europe in 1816. Meteorites have caused more significant effects blocking out sunlight. It is believed that this contributed to a mass extinction 65 million years ago when a meteorite hit the coast of Mexico. Ash layers can be seen in Kamloops From an eruption 7700 years ago in Mount Mazama. “Civilization exists by geological consent – subject to change without warning” Will Durant Concept Check p. 471-473 1. What is the most abundant greenhouse gas in the atmosphere? 2. What property of water is affected by temperature and salinity? 3. What is the name of the event that causes periodic warming of waters in the Pacific ocean? The current change in global temperature over the Last 60 years has caused a 0.74 oC increase in _____________ temperature. Computer models suggest we could experience as high as 6oC increase in average temperature in the next 100 years. The difference between an ________________ the difference between ______________________________________ an ice age and current Climate is about 3-5oC. The complexity of the climate systems means computer models can not accurately predict the outcome. Human activities have caused a Net addition of 15 gigatonnes of carbon dioxide to be added into the atmosphere Enhanced Greenhouse effect _________________________________ Atmosphere absorbs more radiation _________________________________ and emits more infrared radiation. Global Warming Potentials (GWP) CO2= 1 Nitrous oxide(N2O)= 298 Methane(CH4)=25 Chlorofluorocarbons(CFC)= 4750-5310 revolution has lead Carbon Dioxide: Industrial _______________ To a massive increase in our consumption of ___________________. Fossil fuels. - _____________ Deforestation removes a carbon sink and releases CO2 back into the atmosphere. Reduce energy demand and production. - ________ - Use Energy from sources other than fossil fuels Reforestation is another way to remove CO2. - _____________ Methane CH4: Methane is less abundant in the atmosphere but more efficient than CO2. decomposition Released from _______________ animal digestion (landfills) and ________________ fossil (Cows) and extraction of _______ Fuels. __________. Nitrous Oxide (N2O): Produced from biological processes and __________ nitrogen _____________ as well as automobile fertilizers ______________. exhaust. Ozone(O3): forms the ozone layer 10 to 50km blocking out UV radiation. However ozone forms from ________ fossil fuel ____________ Combustion and ______________. air pollution. Chlorofluorocarbons: Man made Chemicals used in refrigerators. These resulted in the ____________ ozone hole As well as being powerful ________ greenhouse ___________. Gases. Albedo and Climate: Some pollutants affects the amount of solar radiation Reaching the surface. Different substances have different Albedo forests and ice are thought high albedo To be important due to __________ Concept Check • What is the difference between the natural greenhouse effect and the enhanced greenhouse effect? • What does GWP describe • List the greenhouse gases that are released when fossil fuels are burned • Name a greenhouse gas that doesn’t occur naturally Global Impact of Climate Change: Some models predict a _______________ 6oC increase in ____________________________________________ in the next 100 years. Temperature and a 88cm rise in sea levels Impacts of climate change on Canada: The affects of global warming could be More severe in Canada because we are in the northern hemisphere. _____________________are beginning As sea ice and Permafrost to melt affecting life in the north. Weather patterns are changing with increased ___________________. precipitation In Alberta aspen trees bloom 28 days earlier than 100 years ago. _______________ could be severely affected by these changes. Agriculture Changes in water temperatures and currents can devastate fish populations affecting fisheries. _________________. Forestry ____________ may also be affected with increases forest fires and insect infestations. Increased temperatures may affect health causing worse ___________ air pollution in the summer. __________________________ to survive farther north and increased population. Disease carrying insects More ___________________ may damage infrastructure causing power outages. violent storms Impacts of Climate Change on British Columbia: A possible 30cm rise in sea level would cause significant flooding threat of ___________ to coastal communities. Drought will increase forest fires _________ and the spread of certain trees and grasslands. Salmon may migrate north towards colder water being replaced by Mackerel and tuna. Glaciers _______________ are an important source of fresh water in BC climate change is causing them to shrink Uncertainty and Decision: 1) Climate change will not greatly affect our lives or environment 2) Climate Change will cause drastic changes in weather patterns that will greatly affect our lives and the environment. Precautionary Principle: A lack of complete scientific certainty should not be used as a cost-effective measures to prevent _________________________. serious environmental damage Reason to postpone ___________________________