Climate Change II Lecture 28 F24 PDF

Climate Change II “The belief that this enormous, existential problem could have been fixed if all of us had just tweaked our consumption habits is not only preposterous; it’s dangerous… …When people...

Climate Change II “The belief that this enormous, existential problem could have been fixed if all of us had just tweaked our consumption habits is not only preposterous; it’s dangerous… …When people come to me and confess their green sins…I want to tell them they are carrying the guilt of the oil and gas industry’s crimes. That the weight of our sickly planet is too much for any one person to shoulder.” - Mary Annaïse Heglar, environmentalist ©McGraw-Hill Education © Maureen Padden  The 20th Century 20th century began as warm as any time in past 1,000 years Warming in 20th century unprecedented in recent past Solar output responsible for less than 10% of warming Major causes of warming are greenhouse gases and aerosols Average global surface temperatures rose 0.6 degrees C in 20th century, from 1910 to 1944 and since 1977 ©McGraw-Hill Education © Maureen Padden  The 20th Century Warming since 1977 twice that of 1910-1944: due to greenhouse gas buildup in atmosphere Natural causes 0.2 °C: Changes in Earth’s orbital patterns : −0.02 degrees C Hotter Sun : +0.22 degrees C increase Human activities 0.4 °C increase Start of 21st century: Rate of annual temperature increase declined, then all-time highs in 2014, 2015, 2016 Annual temperature since 1977 have all exceeded 20th century average annual temperature ©McGraw-Hill Education © Maureen Padden  Northern Hemisphere Temperature Trend – the “Hockey Stick” Figure ©McGraw-Hill Education © Maureen Padden Visualizing Climate Change Toronto 1841 - 2017 annual temperatures The colour scale goes from 5.5°C (dark blue) to 11.0°C (dark red) https://www.climate-lab-book.ac.uk/2018/warming-stripes/ © Maureen Padden  The 21st Century 2021 updated report by Intergovernmental Panel of Climate Change Warming of 1.09 degree C between 1850-1900 and 2011-2020 ©McGraw-Hill Education © Maureen Padden  45 Causes Humans are extracting carbon stored underground (ex. Fossil fuels) and transferring them to the atmosphere faster than they can be removed by natural sinks © Maureen Padden  46 Causes: Destruction of Carbon Sinks Human land use (ex. Deforestation for agriculture) is decreasing the capacity of soil sinks. © Maureen Padden  Causes: What about… The Sun? Sun’s energy has been decreasing since 1970’s Volcanoes? Less than 1% of CO2, less than 15% of CH4 (methane) Cosmic rays? - effect of cosmic rays on cloud cover small and should be causing cooling now Orbital cycles? - we should be cooling, according to orbital cycles © Maureen Padden Impacts: Changes in Hazardous Weather Storm intensity and duration will likely increase. Tropical cyclone wind speeds increase with global warming. Polar front is likely to shift northward: Number of mid-latitude cyclones may decrease. Nor’easters may strengthen in warmer ocean water. Intensity of heavy rains will increase with global warming. Heat waves and droughts are on the increase. © Maureen Padden  52 Changes in Precipitation Worsening floods in some areas; droughts in others; decreased water quality © Maureen Padden  50 Impacts: Future Sea Level Rise ~10% of humanity lives near coasts < 10 m above sea level. Coastal areas are at increasing risk of flooding and destruction from tropical cyclones. Coastal wetlands are at risk. Fresh groundwater supplies are at risk from saltwater contamination. © Maureen Padden  Impacts: Biosphere Changes Climate zones will continue migrating. Temperate forests will grow in areas that are now tundra. By 2100, Illinois may have a climate resembling Louisiana. Corn and soybean crops will be best suited to grow in Canada. Climate-sensitive animal species face extinction as habitat shrinks. © Maureen Padden  First, what not to do Fear, shame and guilt cause us to freeze and feel hopeless. Playing “gotcha” with other people is often less about other people and more about our own fear. Learn about the problem, talk about the problem, know that there are solutions and know that climate change can’t be solved by individual action alone. © Maureen Padden  What to do: Decrease use of Fossil Fuels Challenges: Historical and projected global energy demand - high energy densities. - infrastructure exists - price Reducing fossil fuel use: Energy conservation Alternative energy resource use Solar, tidal, geothermal, wind, hydropower, biofuels, nuclear © Maureen Padden  Everyone Needs Energy Efficiency - easiest change to make - most likely to produce win-win Subsidies - fossil fuel industries are highly subsidized in Canada and US No silver bullet - different non-carbon energy solutions for different uses and different places © Maureen Padden  What to do: Remove GHGs from Atmosphere Carbon capture and sequestration: Trapping CO2 at its emission source Pumping liquefied CO2 into underground rocks Planting more forests, protecting wetlands to increase photosynthesis © Maureen Padden  A word about Geoengineering - using sulphate particles in atmosphere to reflect solar radiation, simulating a volcanic eruption ©McGraw-Hill Education © Maureen Padden  What to do: Adapting to a Hotter World Mitigation efforts may stop temperature rising >2°C. Adaptation tactics: Building seawalls to prevent flooding Broadening wetlands to lessen storm surge impacts Improving air conditioning technologies Hold governments accountable to Improving irrigation methods climate targets from international Developing new crop varieties agreements. © Maureen Padden