ENVIR101 Lecture 02 Carbon Cycle Sp2025 PDF

# Anthropogenic Carbon Sources ## Monthly mean CO2 concentration - Mauna Loa 1958 - 2022 - Y-axis: CO2 fraction in dry air (µmol/mol) - The graph shows an upward trend of CO2 concentration between 1960 and 2022. - **Seasonal variations**: the inset graph displays a seasonal variation of CO2 concent...

# Anthropogenic Carbon Sources ## Monthly mean CO2 concentration - Mauna Loa 1958 - 2022 - Y-axis: CO2 fraction in dry air (µmol/mol) - The graph shows an upward trend of CO2 concentration between 1960 and 2022. - **Seasonal variations**: the inset graph displays a seasonal variation of CO2 concentration from January to October. The y-axis of the inset graph is the departure from yearly average CO2 concentration (µmol/mol). ## Anthropogenic Carbon Sources - **(a) Atmospheric CO2 concentrations IPCC AR6 (2021):** - Y-axis: ppm - The graph displays the atmospheric CO2 concentrations from 60 million years BCE to 2100 CE. - It shows various emissions scenarios: SSP5-8.5, SSP4-6.0, SSP2-4.5, SSP1-1.9. - The highest emissions scenario shows an increasing trend in CO2 concentrations over time. - **(b) Atmospheric Carbon Dioxide measured at Mauna Loa, Hawaii:** - Y-axis: Carbon dioxide concentration (ppmv) - The graph displays the atmospheric CO2 concentrations at Mauna Loa from 1960 to 2010. - The graph shows a clear upward trend of CO2 concentration over time, with variations caused by the annual cycle. ## Changes in global carbon cycle - Changes in CO₂ concentrations occurred long before humans were on Earth. - Human population growth and socioeconomic development are changing the global carbon cycle. - Burning fossil fuels is the strongest source of CO2. - Atmospheric CO₂ concentrations increased from 280 ppm (Industrial revolution) to 350 ppm (when first learned science) to 410 ppm (last year). ## Global fossil fuel & industry emissions, 2014 - **(a) Fossil-fuelled power plants (particularly coal and oil)** - **(b) Road transport (cars, trucks and two-wheelers)** - **(c) Residential use of fossil fuels and bioenergy** - **(d) Industry (combustion and industrial processes)** - **(e) Non-road transport (airplanes, ships, trains)** - **(f) Mining activities** - **Pie chart**: The chart displays the contribution of various sectors to the global fossil fuel and industry emissions. The largest portion of emissions comes from: - Electricity (26%) - Load-following electricity (12%) - Other industry (14%) - Residential, commercial (10%) - Short-distance med/heavy road transp. (5%) - **Emissions**: 33.9 Gt CO2 ## ESG will be a heavy focus for tech leaders in 2023 - **Key points**: - CIOs are becoming increasingly more critical for companies. - Rising environmental regulations, cost savings, and other benefits come from operational efficiencies tied to sustainability and ESG. - The biggest technological challenge for organizations working to improve their operations is a lack of quality data. ## Fossil Fuels - **Combustion of fuels releases energy and produces CO2.** - **Stationary combustion sources:** - Power stations, industry (e.g., boilers, heaters, furnaces, kilns, ovens, flares, thermal oxidizers, dryers) - **Mobile combustion sources:** - Onroad vehicles: - Passenger Cars: Gasoline - Vans, Pickup Trucks & SUVs: Diesel Fuel - Heavy-Duty Vehicles: Diesel Fuel - Combination Trucks: Diesel Fuel - Buses: Diesel Fuel - Nonroad Vehicles: - Construction Equipment: Diesel Fuel - Agricultural Equipment: Diesel Fuel - Forklifts: Diesel Fuel - Other Nonroad Equipment: Diesel Fuel - Waterborne: - Ships: Diesel Fuel - Boats: Diesel Fuel, Residual Fuel Oil, Gasoline - Rail: - Freight Trains: Diesel Fuel - Commuter Rail: Diesel Fuel - Amtrak: Electric - Air: - Commercial Aircraft: Kerosene Jet Fuel - Executive Jets: Kerosene Jet Fuel - **How about burning "renewable" biomass?** ## Methane (CH4) - **Agriculture-based** - **Natural gas-based** - **Petroleum-based** - **Other sources (Burning of biomass, coal mining, treatment of organic waste and wastewater)** - **Diagram of Methane production in a cow's rumen:** - CH4 is produced through the enteric fermentation process in a cow's rumen. - This process is driven by fungi, protozoa, and bacteria. - It starts with the consumption of food (sugars and carbohydrates) and ends with the production of methane. - The process also produces volatile fatty acids and CO2. ## Carbon Emission & Energy Consumption - **Carbon dioxide emissions by source since 1880** - The graph displays the carbon dioxide emissions from different sources since 1880. - The main contributors in recent years have been: - Coal - Oil - Gas - The graph showcases an overall increasing trend of emissions over time. ## CO2 emissions drop the most ever due to the COVID-19 crisis - **Global energy-related CO2 emissions and annual change, 1900-2020:** - Y-axis: Gt - The graph displays the global energy-related CO2 emissions from 1900-2020. - It shows an overall upward trend of emissions, with some dips related to major events like the Great Depression, World War II, the Second Oil Shock, and the recent Financial Crisis. - The graph also shows an annual change in emissions. - The graph indicates a significant drop in 2020, likely due to the COVID-19 pandemic. - **Global energy-related CO2 emissions are set to fall nearly 8% in 2020 to their lowest level in a decade. Reduced coal use contributes the most. Experience suggests that a large rebound is likely post-crisis.** ## Fossil fuels (Coal, oil, gas) - **Increase in depth of burial and temperature:** - The diagram shows different types of fossil fuels (coal, oil, gas) formed by organic material under different conditions of depth and temperature. - The different types of coal are: - Peat - Lignite - Sub-Bituminous - Bituminous - Anthracite - The diagram also states the approximate carbon content of these coal types.