Climate Change Lecture Notes PDF

Climate Change Dr. Neil J. Porter Natural Hazards and Disasters – ESCI-1000 The lecture material is the intellectual property of Dr. Neil J. Porter. Distribution or publication of t...

Climate Change Dr. Neil J. Porter Natural Hazards and Disasters – ESCI-1000 The lecture material is the intellectual property of Dr. Neil J. Porter. Distribution or publication of this material in whole or in part is illegal, under the Canadian Copyright Act, RSC 1985.  Climate Change Overview 9.0 Climate, Weather and the Atmosphere 9.1 Climate Change on Short Term Scales 9.2 Hazards Associated with Climate Change 9.3 Minimizing the Effects of Global Warming  Climate Change 9.0 Climate, Weather and the Atmosphere Currently, the climate is warming Based on decades of warming in atmosphere Also, global increase in sea temp, widespread melting of snow, glaciers, ice sheets, and permafrost, and sea level rise Earth’s climate includes interactions of: Atmosphere, Hydrosphere, Geosphere, Biosphere, Cryosphere.  Climate Change 9.0 Climate, Weather and the Atmosphere Referred to as global warming 99% probability that humans are responsible Ecosystems capable of adjusting, but changes are too fast for these to take place  Climate Change 9.0 Climate, Weather and the Atmosphere Weather – Climate –  Climate Change 9.0 Climate, Weather and the Atmosphere Earth’s temperature depends on three things: 1. Amount of sunlight received 2. Amount of sunlight reflected 3. Degree to which the atmosphere retains heat  Climate Change 9.0 Climate, Weather and the Atmosphere Greenhouse effect is a natural and necessary process. All surface water would be frozen. Little life would exist. Natural effect is from water vapor. 66–85% of greenhouse effect Absorption by greenhouse gasses (carbon dioxide, methane, nitrous oxide, CFCs and ozone) Enhance the greenhouse effect  Climate Change 9.0 Climate, Weather and the Atmosphere Concentrations of which do not change Ex: Nitrogen composes about 78% of the volume of all permanent gases Relatively unimportant to atmospheric dynamics Concentrations of which vary in time and space Ex:  Climate Change 9.0 Climate, Weather and the Atmosphere – Carbon Dioxide Makes up a very small percentage of the atmosphere Released naturally by volcanic activity, plant and animal respiration, wildfires, and decay of organic material Removed through photosynthesis, chemical weathering, and absorption by sea water seawater It also enters the atmosphere through the burning of fossil fuels by people Increased greatly since the Industrial Revolution  Climate Change 9.0 Climate, Weather and the Atmosphere: Carbon Dioxide Recent change unprecedented, more likely the result of human activity rather than natural causes  Climate Change 9.0 Climate, Weather and the Atmosphere: Methane (CH4) Primary constituent of natural gas Occurs naturally from bacterial decay, intestinal tracks of termites, cows, and sheep Anthropogenic sources: coal mines, oil wells, leaking natural gas pipelines, rice cultivation, landfills, and livestock Levels have doubled since 1700 and is a significant contributor to warming  Climate Change 9.0 Climate, Weather and the Atmosphere: Ozone O3 Forms when atomic oxygen (O) collides with oxygen molecule (O2) Mostly found in stratosphere Acts as a shield for ultraviolet light and is essential to life on earth partially destroyed ozone shield Increases skin cancer, cataracts, caused local crop failures  Climate Change 9.0 Climate, Weather and the Atmosphere: Aerosols Microscopic liquid or solid particle that acts as nuclei for water particles to condense to form clouds Associated with air pollution Natural sources: desert dust, wildfires, sea spray, and volcanoes Anthropogenic sources: burning of forests and fossil fuels Effects are complex  Climate Change 9.0 Climate, Weather and the Atmosphere Paleoclimatology Analyzing proxy data in order to reconstruct past climates Proxy data – indirect evidence using natural recorders of climate variability 1. 2. 3. 4. 5. 6.  Climate Change 9.0 Climate, Weather and the Atmosphere 1. Growth of trees depends on rainfall and temperature Dendroclimatology: climate data provided by tree rings Proxy record that extends back more than 10,000 years  Climate Change 9.0 Climate, Weather and the Atmosphere 2. Recovered by coring lakes and ocean basins Samples are analyzed to provide data on climate change  Climate Change 9.0 Climate, Weather and the Atmosphere 3. Obtained by drilling into the ice Contain small bubbles of air deposited at the time of snow Composition of past atmospheric gases are studied  Climate Change 9.0 Climate, Weather and the Atmosphere 4. Their skeletons have alternating light and dark layers that result from seasonal changes in growth rates. The light and dark layers represent annual bands, similar to tree rings, that can be used to determine the age of the coral skeleton. Variations in the chemical http://www.earthtimes.org/climate/growth-rings-deep-sea-corals-reveal-climate-data/201/ composition of the skeleton can be calibrated to environmental parameters such as seawater temperature, salinity, and pH as the coral grows. https://earthobservatory.nasa.gov/Features/Paleoclimatology_CloseUp/paleoclimatology_closeup_2.php  Climate Change 9.0 Climate, Weather and the Atmosphere 5. Accumulates with sediment in a variety of environments The types of pollen found reflects climate Preserved in sediment layers that can be independently dated A chronology can be developed Composition of past atmospheric gases are studied  Climate Change 9.0 Climate, Weather and the Atmosphere 6. Books, newspapers, personal journals, ship logs, crop records Measurements of temperature and precipitation date to the late 17th century Carbon dioxide in the atmosphere has been measured since 1958  Climate Change 9.1 Climate Change on Short Term Scales: Solar energy changes 1. Variable energy from the Sun over time 2. Luminosity 3. Sunspots 4. Faculae Lack of correlation between solar activity and average Earth temperature.  Climate Change 9.1 Climate Change on Short Term Scales: Milankovitch Theories 1. 2. 3.  Climate Change 9.1 Climate Change on Short Term Scales: Changes in Earth’s orbit around Sun, tilt and wobble of Earth’s axis of rotation. – 100,000yrs – orbit – 41,000 yrs – angle of Earth’s axis – 26,000 yrs wobble of axis Variations contribute to glacial and interglacial episodes  Climate Change 9.1 Climate Change on Short Term Scales: Ash from eruptions becomes suspended in the atmosphere, reflects sunlight having a cooling effect. Mount Tambora, 1815 eruption contributed to cooling in North America and Europe. Volcanic ejecta may block sunlight Need many eruptions in short time period Not observed in recent history  Climate Change 9.1 Climate Change on Short Term Scales: Intergovernmental Panel on Climate Change (IPCC) Global group of scientists Peer-reviewed literature Published assessments since 1990 There is sufficient evidence to state: 1. There is widespread evidence of human influence on global climate. 2. Warming is now occurring. 3. Mean surface temperature of Earth will likely increase between 1.40 and 5.80 C during this century.  Climate Change 9.2 Hazards Associated with Climate Change: Sea surface temperatures risen mostly since 1970 Deep waters showing increases  Climate Change 9.2 Hazards Associated with Climate Change: Ocean conveyor belt Circulation of ocean water in oceans Can cause fast changes in climate Keeps Northern Europe warmer than without it Cold dense water sinks - oxygen  Climate Change 9.2 Hazards Associated with Climate Change: Warmer water fuels hurricanes Severity of recent Atlantic hurricanes Number of global tropical storms have not increased worldwide Intensity of storms has increased More Category 4 and 5 hurricanes  Climate Change 9.2 Hazards Associated with Climate Change: Climate Patterns Changes in Climate Patterns: Temperature and precipitation patterns, soil moisture Increase in the frequency or intensity of violent storms Change in the frequency and strength of El Niño and La Niña events  Climate Change 9.2 Hazards Associated with Climate Change: Main contributors: Melting of Antarctic and Greenland ice sheets Thermal expansion of ocean surface waters Melting of land glaciers and ice caps Thermal expansion of deep-ocean waters  Climate Change 9.2 Hazards Associated with Climate Change: Arctic amplification Loss of more than 2 million square kilometers (800,000 square miles) of Arctic sea ice in last decade Loss of ice = enhanced warming due to lower albedo  Climate Change 9.2 Hazards Associated with Climate Change: Arctic ice melting affects polar bear survival. Food sources are dwindling for human Arctic dwellers. Marine species migration  Climate Change 9.2 Hazards Associated with Climate Change: Climate Patterns North West Passage  Climate Change 9.2 Hazards Associated with Climate Change: Climate Patterns Release of carbon dioxide into the atmosphere from the decay of organic sediments  Climate Change 9.2 Hazards Associated with Climate Change: Climate change models can mimic modern conditions only if human emissions are taken into account. IPCC assessments continue to provide strong documentation of human-induced climate change. The concentration of atmospheric carbon dioxide was approximately 280 ppm in 1750 Expected to reach at least 460 ppm in 2050  Climate Change 9.2 Hazards Associated with Climate Change: Some atmospheric carbon dioxide dissolves in ocean water – produces carbonic acid Acidifies ocean Unable to make calcium carbonate shells Threatens calcifying organisms such as Coccolithophores, Foraminifers, Sea urchins and corals  Climate Change 9.2 Hazards Associated with Climate Change:  Climate Change 9.2 Hazards Associated with Climate Change: Climate Patterns Human-induced degradation of productive land Preceded and accompanied by loss of vegetation and soil erosion Land may lose productiveness and not recover for decades or centuries Could increase in length and severity Areas that become drier and warmer will have more droughts Drought in Canada could be exacerbated by a reduction in the amount of snow and glacier ice Will have an effect on summer streamflow in many areas  Climate Change 9.2 Hazards Associated with Climate Change: Climate Patterns An increase in wildfires in many regions Accelerate replacement of ecosystems that are poorly adapted to a warmer climate with ones that can tolerate more warmth  Climate Change 9.3 Minimizing the Effects of Global Warming: International Agreements 1987 agreement to limit depletion of the ozone layer by CFCs CFCs have declined since the protocol was implemented 1997 agreement from the United Nations Framework Convention on climate change Establishes targets for nations to reduce greenhouse gas emissions by 2012 Canada was a signatory but recently withdrew after emission targets were not being met Withdrawal of the U.S. has severely reduced its effectiveness  Climate Change 9.3 Minimizing the Effects of Global Warming: International Agreements Summit in The Hague, 2000 2000 conference that focused on alternative methods to reduce emissions including: Clean development methods that improve the carbon balance of developing nations Joint implementation, which allows emission credits to be shared between developing countries and wealthy countries Emission trading, where countries that easily meet targets can sell credits to countries that fail to meet their own The conference ended without an agreement The agreement sets out a global action plan to put the world on track to avoid dangerous climate change by limiting global warming to well below 2°C. The US withdraws from the accord – only country do to so. Recently signed on  Climate Change 9.3 Minimizing the Effects of Global Warming: Carbon Sequestration A process that refers to the capture and storing of carbon dioxide before it enters the atmosphere Planting more trees Injecting carbon dioxide deep in the oceans Power plants and industrial facilities designed to capture CO2 CO2 is then compressed and injected under pressure into wells drilled into the crust  Climate Change 9.3 Minimizing the Effects of Global Warming Two scenarios for climate change and sea level rise during the next 100 years Both scenarios assume economic growth, with population peaking in the middle of the 21st century Scenario 1 More efficient energy technologies, but still fossil fuel intensive Average temperature will rise by about 4.5°C and sea level may rise by 1.4 m Scenario 2 Clean resource-efficient technologies, economic systems change Average temperature will rise by about 2°C and sea level may rise by 0.5 m