The Carbon Cycle & Forests
Where does a giant Redwood tree get the vast majority of its physical mass (weight) as it grows from a tiny seed?
From carbon pulled out of carbon dioxide CO2 in the atmosphere during photosynthesis.
Approximately how many million tons of plastic enter the global oceans every single year?
Over 8 million tons
What are the five chronological stages of a product's life cycle evaluated in a standard LCA?
1. Extraction
2. Production
3. Distribution
4. Consumption
5. End of Life.
What is the specific term for the highly toxic, contaminated liquid that forms when rainwater percolates down through decomposing landfill waste?
Leachate.
Approximately what percentage of global greenhouse gas emissions comes from burning fossil fuels?
Approximately 75%.
In the carbon cycle, what term describes a living, growing forest that actively absorbs and stores more carbon than it releases?
A Carbon Sink
How big are microplastics?
Less than or equal to 5 millimeters (mm)
What is the difference between a "Cradle-to-Grave" boundary and a "Cradle-to-Cradle" boundary?
Cradle-to-Grave tracks a product from raw materials to disposal (waste), whereas Cradle-to-Cradle designs the product so it can be continuously recycled or composted, eliminating waste entirely.
Why are modern sanitary landfills referred to by environmental scientists as "Trash Tombs"?
They seal waste in dry, oxygen-free (anaerobic) conditions, which halts decomposers and slows the decay of trash to a near-complete stop.
What is the term for the minimum amount of continuous, reliable electricity that a power grid requires 24 hours a day?
Baseload Power.
How does logging and clearing a forest change its role in the global carbon cycle?
It turns the forest from a carbon sink into a carbon source (releasing carbon).
What is the "Sponge Effect" in landfill engineering?
Wild Card: 300 points free!
During which specific LCA stage of a smartphone does the consumption of electrical energy from charging the battery take place?
The Consumption (or Use) stage.
What dangerous greenhouse gas is produced inside landfills by anaerobic bacteria breaking down organic waste?
Methane gas (CH4)
What subatomic particle is fired at a Uranium-235 nucleus to split it and trigger a nuclear fission chain reaction?
A neutron
Why doesn't planting 100 tiny saplings immediately balance out the carbon loss of cutting down one giant, mature Redwood tree?
Saplings have tiny leaf surface areas and absorb carbon at a tiny fraction of the rate of a massive, mature tree.
What ecological term describes how toxins and microplastics build up inside the body of a single organism over its lifetime?
Bioaccumulation.
Sourcing raw cobalt and lithium from deep mines for electric car batteries belongs to which stage of an LCA?
The Extraction stage.
This massive, floating vortex of plastic debris spinning in the ocean between California and Hawaii is kept trapped in place by a rotating system of ocean currents called a gyre.
The Great Pacific Garbage Patch
What is the function of control rods inside a nuclear reactor core?
They slide into the core to absorb excess neutrons, allowing operators to slow down or stop the fission chain reaction.
When extra carbon dioxide CO2 is pumped into the atmosphere, what happens to the Earth’s "Greenhouse Blanket"?
It thickens, trapping more thermal heat near the Earth's surface.
Why are microplastics particularly dangerous to the base of the marine food web?
They are small enough to be easily consumed by microscopic organisms like zooplankton, introducing toxins to the entire food chain.
Why does transporting cargo by airplane have a vastly higher carbon footprint per ton than transporting cargo by container ship?
Airplanes travel faster but burn significantly more fuel, producing much higher greenhouse gas emissions per ton of cargo.
What is the purpose of the thick clay and synthetic plastic liner placed at the very bottom of a sanitary landfill?
To prevent toxic leachate from seeping down and contaminating groundwater aquifers.
While nuclear power plants have the massive advantage of producing zero direct greenhouse gases during operation, what is their primary environmental disadvantage?
They produce high-level radioactive waste that must be stored safely for thousands of years.