Topic 5: Climate Change - PDF

Topic 5: Climate Change  Studying Climate History How do we study the composition and temperature of the atmosphere thousands of years ago? We can also study past climates using “proxy” methods. Earth Thermometers have been aro...

Topic 5: Climate Change  Studying Climate History How do we study the composition and temperature of the atmosphere thousands of years ago? We can also study past climates using “proxy” methods. Earth Thermometers have been around itself holds records of past since 1850! We have some climates in tree rings, ice, coral written records (logs, diaries, lists) growth-bands, cave deposits, of temperature and precipitation. ocean or lake sediments! Past Climates  Past Temperatures How would we make a graph like this? We make a graph about climate history, we have to use climate proxies. These proxies allow us to reconstruct climate conditions over all of Earth’s history. What are climate proxies? How do scientists study climate? Climate Proxies & Models Ice cores Tree rings Sub-fossil pollen Corals Lake and ocean sediments Cave formations Computer modelling  Climate Proxies: Ice Cores Long cylinders of ice drilled from glaciers and ice sheets. – Primarily taken from Greenland and the Antarctic We can learn about 1. Glacier cycles 2. Changing CO2 levels 3. Climate over last 10,000 years 4. Volcanic eruptions 5. Nuclear disasters Temperature Changes Past 400,000 Years Factors that Cause Climate Change  Factors that cause climate change 1. Natural changes to Earth’s orbit 2. Natural changes to the Sun, which affect incoming solar radiation 3. Natural, large-scale volcanic eruptions which release lots of SO2(g) into the air – SO2 reflects heat and causes cooling periods! 4. Changes to the atmospheric chemistry (greenhouse gases are in the air) – Some gases are natural, others are manmade  Greenhouse Effect Greenhouse effect is a natural process that makes Earth liveable (warm enough!) Without greenhouse gases, Earth’s average temperature would be below freezing! When Sun’s energy reaches Earth, some of it is absorbed by greenhouse gases  Greenhouse Gases Any gas that has the ability to trap heat – CO2(g) = main greenhouse gas – CH4(g) – N2O(g) – CFC(g) & other fluorinated gases – H2O(g) NASA – CO2 Plumes  Global Warming A gradual increase in the overall temperature of Earth’s atmosphere – Largely caused by greenhouse gases like carbon dioxide, chlorofluorocarbons and methane coupled with deforestation  Climate Change A change in global or regional climate patterns – Largely attributed to increased levels of carbon dioxide produced by fossil fuel combustion but also other greenhouse gases Greenhouse Global Climate Gases Warming Change Significant changes to 1. Temperature 2. Rainfall 3. Moisture 4. Wind velocity Climate Change is a Complex Problem Since the Industrial Revolution, the human population has grown exponentially Climate Change is a Complex Problem Developed countries use 75% of the world’s energy output – US is only 5% of the world’s population but uses 25% of the world’s energy output As countries develop and become more and more industrialized, Who’s problem is it?! Greenhouse Gases by Sector Greenhouse Emissions  Global Warming Potential (GWP) Relative measure of how much heat a greenhouse gas traps in the atmosphere. We compare the same mass of each gas to determine this value. Who is responsible for climate change – what needs to fix it?  Carbon Dioxide Enters the atmosphere through burning fossil fuels (coal, oil, natural gas), solid waste, tree and wood products, cement manufacturing GWP = 1 – The problem is not that it has a high GWP, problem is there is large mass of it in air Carbon Dioxide Levels Carbon Dioxide Levels CO2 Emissions and Human Population CO2 Emissions and Human Population  Methane Emitted from – the production and transport of coal, natural gas, and oil – Livestock industry and other agricultural practices – Decay of organic waste in landfills GWP = 25 CFCs and other Fluorinated gases Have the highest GWPs of any greenhouse gases Released in much lower quantities than CO2 and CH4 CFCs are in the air from old fridges, air conditioners and aerosols (these are banned but CFCs have a long lifespan)  Nitrous Oxides (N2O) Emitted during agricultural and industrial activities (anytime you have to burn something!) Burning fossil fuels and solid waste GWP = 298  Water Vapour Water has a high specific heat capacity, and can hold heat for long periods of time Water vapour is the most abundant greenhouse gas in the atmosphere, but because it plays a major role in What is this??? determining climate through the water cycle its role in climate change is still not well understood  Water Vapour: Greenhouse Gas? (Explained by NOAA) As temperature rises, more water evaporates, which raises humidity (humid air absorbs heat!) But as it warms, more water evaporates… further warming the air (a positive feedback loop) The issue is… the greater the water vapour in the air, the more clouds form (which reflect sunlight, and therefore should cool Earth) There is a positive trend that water vapour levels in the atmosphere are on the rise, therefore, that water vapour is likely contributing to greenhouse effect Impact of Climate Change on You Potential Climate Change Impacts  Viewpoints or Perspectives Ecomonic: How will the issue affect finances of a country, of communities, of individuals? Environment: How will the issue affect the environment (plants, animals and their habitats) Societal: How will the issue affect demographics of a community – the way people live, work, and think  Viewpoints or Perspectives Ethical: What is the moral thing to do concerning the issue (what is the “right” thing to do)? Cultural: How does the issue affect social norms of a group of people? Political: How do political policies (laws, bylaws, tarrifs, etc) shape or help the issue?  Examples Cultural perspective refers to the way people are shaped by their environment through factors like nationality, race, gender, religion, spirituality Culture includes the symbols, languages, beliefs, values, and artifacts that are part of a society – For example: The catholic church opposes all forms of abortion and a devout catholic may be raised with these beliefs and may say something like “human life must be respected and protected from the moment of conception, abortion goes against my beliefs”  Social Perspective The word “social” means relating to society and its organization Alberta is a society, although it includes many cultural groups At times, factors will affect all Albertans despite their economic, political or cultural views – For example, if we lost thousands of jobs in Alberta (like we did two years ago when oil prices plummeted) that had a major impact on Alberta’s communities – Small businesses lost income as people have been spending less – People did not attend as many city events etc Perspective? Viewpoint? Viewpoint?  Viewpoint? NASA Scientist Viewpoint on Climate Change Viewpoint? Viewpoint?  What can we do to reduce our impact on greenhouse gas emissions? 1. Be energy efficient (upgrade existing infrastructure, unplug unused devices known as power vampires) 2. Choose renewable power technologies if possible 3. Eat wisely – do you know where your food comes from? 4. Recycle carefully, buy recycled products 5. Fly less (planes produce large CO2 emissions) 6. Be knowledgeable (do you know what consumerism is?) and get involved in your community 7. “Green” your commute (move closer to work, drive less, bike or walk if you can) These steps are a combination of ideas found in Scientific American and David Suzuki's website)  Canada’s Promise to Reduce Greenhouse Emissions Sector Actions Transportation Energy Building construction Agriculture and Forestry Industry  Limitations of Scientific Knowledge in Predicting Weather and Climate We are limited in many ways Incomplete understanding of climate systems Imperfect ability to transform knowledge into math equations (used by computer models) Computer models can only forecast based on past averages and are not always accurate for day-to-day weather and do not always forecast correctly (esp severe weather events like drought) What else? Thoughts? Consequences of Climate Change Less food, less clean water, worsening health (children’s immune systems are still developing and all the forest fire smoke will equate to increasing cancer rates) Many families will have to choose between starvation and migration  Impact of Climate Change on the rainforest Models predict the Amazon will increase by 2-3oC by 2050 (10-20% reduction in rainfall in the Amazon) This will lead to intensified droughts, which in turn will increase forest fires in the Amazon For the last decade, each year the rainforest already receives less rain than before and is creating a chain effect of consequences What do we lose when forests degrade?  Impact of Climate Change on the rainforest The changing temperatures are also causing plants, including fruit trees, to produce fruit earlier than in the past This is throwing off species who are born later in summer and depend on that food It is also causing invasive species to enter the rainforest who normally would have stayed out, and they are outcompeting the natural species  Impact of Climate Change on the rainforest Coffee, bananas, lemons, peanut crops are being affected by pathogens from the dry warmer weather…and when food shortages happen, food prices for these crops increase Fortunately, we have found that rainforests seem to be resilient to drought and can recover after their rainy season – how long can this go on for??