Climate Change & Global Warming

• Weather and climate are not the same

Weather

• It is measured over a short term, day to day
• Refers to changes in the condition of the atmosphere at a certain place and time
• Includes precipitation like rain, snow, sleet or hail, as well as temperature
• Is reported as a temporary forecast
• It is local and varies across similar regions
• Defined as atmospheric conditions like temperature, precipitation, wind, and humidity in a particular region over a short period, like a day or a week
• Example: 20°C with 3mm of rain

Climate

• Measured as an average over a long period of time
• There are six major climate zones: Polar, temperate, arid, tropical, tundra, and Mediterranean
• Encompasses precipitation like rain, snow, sleet, and hail, plus temperature
• It is reported as an average over a long period of time
• Occurs similarly over large regions
• It is the average of weather conditions in a region over a long period, 30 years or more
• Example: hot, humid summers and cold winters with lots of snow

Factors Affecting Climate

• Latitude: Lower latitudes like near the equator receive more sunlight and are hotter
• Altitude: The air is thinner and colder at higher altitudes
• Large Bodies of Water: Water heats and cools more slowly than land, resulting in a smaller range of temperatures in surrounding areas
• Air & Ocean Currents: Warm currents heat the land and cold currents cool the land
• Land Formations: As clouds are blown over a mountain, they lose moisture, causing one side to get more rain and the other side to be dry

Natural Process of the Greenhouse Effect

• Gases and clouds absorb infrared radiation emitted from the Earth's surface and radiate it in all directions
• This process heats the atmosphere and Earth's surface
• Earth's average temperature would be -18°C without the greenhouse effect
• Venus experienced a runaway greenhouse effect, resulting in an average temperature of 462°C
• 96.5% of Venus' atmosphere is carbon dioxide

The Greenhouse Effect

• Some energy from the sun is immediately reflected back into space
• Some energy is absorbed by clouds and greenhouse gases in the atmosphere
• Greenhouse gases in the atmosphere then absorb the radiation and emit it in all directions
• Some energy is absorbed by Earth's surface and water
• Is the natural warming of Earth's surface and lower atmosphere
• It is caused by infrared radiation or heat from the sun that is absorbed and emitted into the atmosphere

Carbon Sink

• It is a reservoir like forests and oceans that removes carbon dioxide from the atmosphere and stores the carbon in a different form

How the Greenhouse Effect Works

• Solar radiation enters Earth's atmosphere as heat energy
• Earth's surface absorbs and reflects solar energy
• The energy is reradiated back into the atmosphere
• Some energy is released back into space
• The remaining energy gets trapped in the atmosphere by greenhouse gases, which causes global temperatures to rise
• Too few gases: Too cold, Too many gases: Too hot.

Greenhouse Gases

• These gases are important to life on Earth because they maintain a comfortable temperature
• A small change in global temperature can upset Earth's systems, causing changes to climates and creating challenges to life
• Definition: A greenhouse gas is a gas in the atmosphere that absorbs infrared radiation and emits it back towards the Earth instead of letting it pass through into space.
• Water vapor is the most abundant greenhouse gas and enters the atmosphere through evaporation, transpiration, and volcanic activity

Major Greenhouse Gases and Sources

• Carbon Dioxide: Fossil fuel combustion, deforestation, cement production
• Methane: Fossil fuel production, agriculture, landfills
• Nitrous Oxide: Fertilizer application, fossil fuel and biomass combustion, industrial processes

Ozone

• Ozone in the upper atmosphere is beneficial because it blocks harmful UV rays
• In the lower atmosphere, it becomes a greenhouse gas
• It forms in a follow-up reaction when products of combustion are exposed to sunlight

Methane (CH4)

• It is a product of livestock framing
• Forests are often removed to make room for cattle farms which multiplies GHG problem
• Landfills also release methane

Carbon Dioxide (CO2)

• The amount of this gas in the atmosphere has been quickly rising since the Industrial Revolution
• CO2 levels increase due to deforestation since trees store carbon from the atmosphere, known as carbon sinks

Nitrous Oxide (N2O)

• Agriculture's overuse of fertilizer is the main reason for the increase

Chlorofluorocarbons (CFCs)

• They are from aerosol sprays and refrigerants
• CFCs are responsible for the hole in the ozone layer
• CFCs have been banned in many countries, with over 200 countries agreeing to cease production by 2030

Natural Greenhouse Gas Emissions

• Greenhouse gases are naturally emitted from natural sources
• Earth has systems in place for keeping balance of gases released through natural processes
• The amount of natural greenhouse emissions is very small compared to the amount produced through human activities
• Natural sources include wetland bacteria, volcanic eruptions, wildfires, sediments and oceans, and cell respiration

Combustion

• Burning fossil fuels and organic matter like forests, landfills, and biomass releases heavy amounts of carbon dioxide and other GHGs
• Burning fossil fuels for electricity, industry, and transportation also releases high GHG

Deforestation

• Forests take in and store carbon dioxide during photosynthesis
• Deforestation, or removal of forests, causes less carbon dioxide to be taken out of the atmosphere

Decomposition

• Landfills, organisms, and other organic wastes release methane and other greenhouse gases as they decompose

Agriculture

• Livestock, such as cows, release methane as a byproduct of digestion
• Manure and fertilizers also release greenhouse gases

Industrial Products

• Refrigerants, foam-blowing agents, aerosol propellants, and fire suppressants release powerful greenhouse gases called HFCs

Carbon Dioxide (CO2)

• It is the most abundant greenhouse gas and stays in the atmosphere longer than most greenhouse gases
• Human activities increase atmospheric CO2 levels primarily through the burning of fossil fuels for transportation, heating, and electricity
• CO2 levels are currently 50% higher than the pre-industrial era between 1850-1900

Carbon Cycle and Sinks

• The carbon cycle is the cycling of carbon molecules between oceans, air, organisms, and rocks
• Factors that store or deduct the amount of carbon dioxide in the atmosphere are carbon sinks
• Carbon sinks remove and/or store carbon dioxide
• Examples: oceans, the atmosphere, soil and sediment, forests, organisms

Carbon Dioxide in the Oceans

• Oceans can only absorb so much carbon dioxide and cannot handle the increased concentration of it in its atmosphere
• The ability of the ocean to absorb carbon decreases as the carbon concentration increases
• Excessive carbon dioxide in the ocean warms the ocean to fuel extreme storms and droughts

Ocean Acidification

• Acidic oceans cause coral bleaching, kill fish, and hinder marine organisms' abilities to create shells and skeletons
• Dissolved carbon dioxide in the ocean undergoes chemical reactions to produce carbonic acid, which lowers pH
• Acidic conditions mean inhospitable and dangerous conditions for marine life
• Higher concentrations of carbonic acid and warmer temperatures affect the health of marine ecosystems

Global Warming

• This is the long-term heating of Earth's climate observed since the pre-industrial era between 1850-1900
• It is due to human activities, primarily fossil fuel burning
• It is caused by increased greenhouse gas emissions released into the atmosphere by human activity
• High greenhouse gas concentrations cause global temperatures to increase
• Since the pre-industrial era, human activities are estimated to have increased Earth's global average temperature by about 1°C per decade

Effects of Global Warming

• Warmer temperatures increase the evaporation rate of water, causing water vapor gas to enter the atmosphere
• Water vapor magnifies the effects of other greenhouse gases, contributing to further warming
• Increased evaporation causes increased precipitation and irregular weather patterns

Climate Change

• Climate change is a long-term change in the average weather patterns that define Earth's regional and global climate
• Average change in the climate across the entire globe
• Global warming leads to climate change
• It is primarily driven by human activities

Evidence of Climate Change

• Scientists use observations from the ground, air, and space, along with models to monitor and study the past, present, and future
• Climate change includes global land and ocean temperature increases, sea level rise, sea ice loss, ocean acidification, and more severe and frequent weather

Sea Ice and Glacier Melting

• The Arctic is warming twice as fast as anywhere else on Earth
• Warming temperatures melt sea ice and glaciers at an alarming rate
• Arctic ice helps maintain Earth's temperature and stabilizes weather and ocean patterns
• Melting sea ice leads to warmer air and ocean temperatures, disrupted ocean circulation patterns, more frequent and severe weather, and sea levels rising, shoreline erosion, and coastal flooding

Albedo Effect

• Definition: A feedback loop between temperature and the amount of ice & snow
• Albedo is measured in the range of 0 to 1 and is the percentage of radiation that is reflected. 0 is low and all radiation is absorbed. 1 is high and all radiation is reflected
• Ice & Snow: 0.8
• Clouds: 0.4-0.7
• Sand: 0.25
• Forests: 0.1
• Water: 0.08
• Clouds reflect about 40-70% of the Sun's radiation
• Snow reflects about 80% of the Sun's radiation
• Forests reflect about 10% of the Sun's radiation
• Water reflects about 8% of the Sun's radiation
• High albedo reflects more light than dark-colored or low albedo, compared to land and ocean surfaces
• As warming sea ice melts, fewer light surfaces remain to reflect sunlight back into the atmosphere
• Rates of melting and global temperatures are magnified in a positive feedback loop

Severe Weather

• An increase in the intensity and frequency of extreme weather is one consequence of warming temperatures
• Heat & Drought: Intensified drought in many areas; wildfires are more likely to occur in dryer and warmer conditions
• Storms & floods: Increased frequency and strength of storms and floods and destruction of ecosystems
• Snow & frigid weather: Warmer atmosphere has more moisture, snowfall can break records, and weakened jet stream allows frigid polar air to travel farther south

Human Population Growth

• More humans are impacting climates as the human population on Earth skyrockets
• Consumption of resources and the release of waste products by human activities contributes to climate change
• More people means more greenhouse gas emissions

Global Effects

• Melting Ice Caps: Rising temperatures have accelerated the melting of polar ice
• Sea Level Rising & Flooding: As ice melts, sea levels rise, causing flooding, property damage, and new coastlines
• Invasive Species: Climates change, new species will be able to live in areas they are not meant to be in and disrupt the food web if there are no predators
• Extinction: As food availability decreases, some species are at risk of extinction, which means they would be dying with none left of the species
• Heatwaves: Rising temperatures can stay very high for days or weeks
• Droughts: High temperatures lead to more evaporation, causing droughts
• Food & water Shortages: Climate changes, rising temperatures, droughts, and invasive species affect the food and water supply
• Forest Fires: More hot, dry climates increases the likelihood and intensity of forest fires
• Severe Weather: Higher temperatures lead to more ocean evaporation, causing heavier rainfalls and snowfalls
• Bleached Coral Reefs: Increased ocean temperatures affect coral's food source, causing coral to turn white

Carbon Footprint

• Human activities release carbon into the atmosphere
• A carbon footprint is the amount of carbon dioxide released into the atmosphere because of one's own energy consumption
• Carbon footprints can be calculated by measuring carbon released by activities like transportation, electricity, food, clothing, and purchased goods

Reduce Your Carbon Footprint by:

• Using less fossil fuels by turning off lights, driving less, carpooling, using energy efficient appliances, buying local goods and food, using renewable energy, recycling and reducing
• Supporting change by supporting local and federal legislation that aims to reduce dependence on fossil fuels, supporting local farms, urging others to be more energy efficient, and spreading the word

Explore how human activities elevate atmospheric carbon dioxide, impacting climate change. Understand the role of carbon sinks and the consequences of carbon dioxide absorption by oceans, including global warming and weather patterns. Learn about green house gases and the difference between weather and climate.