Pollution, Carbon & Climate Evidence — Chapter Practice, Grade 12

Fertilizer and motor oil washing off lawns and roads across a whole watershed

Nonpoint-source pollution comes from many scattered, hard-to-identify sources at once, like runoff spread across an entire watershed, rather than from a single identifiable outlet.

a persistent pollutant becomes more concentrated in organisms at each higher step of a food chain

Because predators eat many contaminated prey and store rather than excrete the toxin, persistent pollutants grow more concentrated at each higher trophic level.

20 ppm

Three steps of tenfold magnification: 0.02 × 10 × 10 × 10 = 0.02 × 1,000 = 20 ppm. This supplied teaching factor applies between feeding levels; water-to-organism uptake is bioconcentration.

The fertilizer adds extra nutrients to the water (eutrophication), which fuels a huge algal bloom. When the algae die, decomposers break them down and use up the water's dissolved oxygen. With the oxygen gone, fish and other organisms suffocate, leaving a lifeless 'dead zone.'

It comes from many scattered, diffuse sources spread across the landscape, so there is no single pipe or stack to regulate

Point sources can be sampled and regulated at one outlet, but nonpoint pollution seeps in from countless diffuse locations at once, making it far harder to pinpoint and fix.

Keep concentration and mass per time distinct.

200 mg/s.

State what the supplied observations or conditions establish, and separate that from any assumption.

A substance's harmful potential does not alone determine dose or risk; route, amount and duration matter.

No. It can show exposure/accumulation but a trophic comparison with compatible concentrations is needed for magnification.

Bioaccumulation is buildup within an organism when uptake exceeds elimination over time. Biomagnification is increasing concentration across trophic positions through dietary transfer under appropriate persistence, uptake and elimination conditions. The concepts are related but not identical. Some compounds do neither, and comparing different tissues or wet/dry mass bases can mislead. Specify the chemical, tissue, concentration basis and food-web evidence before asserting a universal higher-predator pattern.

No. It can show exposure/accumulation but a trophic comparison with compatible concentrations is needed for magnification.

Response criteria

• Interpret labels, structures, axes, units and directions correctly.
• Explain the physical or environmental relationship or mechanism.
• Respect stated assumptions and distinguish observation from inference.

Initial mass=200×60×3=36000 mg=36 g. Waterborne residual=7.2 g; captured mass=28.8 g. The captured material remains in the full system account.

Initial mass=200×60×3=36000 mg=36 g.

Waterborne residual=7.2 g; captured mass=28.8 g.

The captured material remains in the full system account.

Response criteria

• Use the stated measurements or conditions, with correct units.
• Connect the result to the physical or environmental mechanism or evidence relationship.
• Identify the assumption, model limit or further evidence requested.

Carbon dioxide (CO2)

Carbon dioxide absorbs and re-emits outgoing infrared heat and is released in huge quantities by burning fossil fuels; nitrogen, oxygen, and argon make up most of the atmosphere but do not trap heat this way.

50 %

The increase is 420 - 280 = 140 ppm; 140 ÷ 280 = 0.5, or a 50% increase.

Glaciers and polar ice sheets are shrinking and global sea level is rising

Shrinking ice and rising seas are among many independent measurements — along with the temperature record and ocean warming — that all indicate a warming climate.

Fossil fuels store carbon that was locked underground and out of the active carbon cycle for millions of years. Burning them releases that ancient carbon as carbon dioxide in just decades or centuries — far faster than photosynthesis and the oceans can absorb it back — so carbon dioxide builds up in the atmosphere.

Weather is the short-term, day-to-day state of the atmosphere, while climate is the long-term average of weather over decades. A single cold day is just weather and doesn't reveal the long-term trend. Climate change is measured by averaging temperature and other data over many years and across the whole globe, which clearly shows warming even though individual cold days still happen.

Weather fluctuations do not directly establish long-term forcing.

Oceans store substantial heat, so air temperature alone does not capture the system's energy change.

State what the supplied observations or conditions establish, and separate that from any assumption.

Future emissions, responses and natural variability depend on uncertain choices and processes.

Positive describes a reinforcing causal loop, not whether the effect is desirable.

A forcing changes the external energy-balance conditions of the chosen system. A feedback is a response pathway that feeds back on the initial change: reduced reflective ice after warming can reinforce additional warming, while increased thermal emission with temperature supplies a stabilizing response. Reinforcing means amplifying, not beneficial; balancing means opposing, not necessarily harmless. Ocean heat capacity and circulation also create delays, so response need not be immediate.

Positive describes a reinforcing causal loop, not whether the effect is desirable.

Response criteria

• Interpret labels, structures, axes, units and directions correctly.
• Explain the physical or environmental relationship or mechanism.
• Respect stated assumptions and distinguish observation from inference.

Increase=(242−240)×10=20 J/m². Temperature change also needs heat capacity, depth/distribution of storage and coupled responses; this is a supplied short model interval, not an actual climate measurement.

Increase=(242−240)×10=20 J/m².

Temperature change also needs heat capacity, depth/distribution of storage and coupled responses; this is a supplied short model interval, not an actual climate measurement.

Response criteria

• Use the stated measurements or conditions, with correct units.
• Connect the result to the physical or environmental mechanism or evidence relationship.
• Identify the assumption, model limit or further evidence requested.

Write the relationship first; substitute with consistent units.

10 times

10¹=10.

Yes; its pH has declined even though it remains basic.

Response criteria

• State a scientifically accurate conclusion.
• Show the calculation or mechanism that supports it.
• Include units, conditions, or limits where relevant.

List the given quantities, select a relationship, and check units before substituting.

1.585 times

10^.20≈1.585.

They are distinct processes: acidification changes chemistry; warming changes temperature, though they can interact.

Response criteria

• State a scientifically accurate conclusion.
• Show the calculation or mechanism that supports it.
• Include units, conditions, or limits where relevant.

Acidification names a shift, not necessarily crossing neutral pH.

10^0.3≈2.0, about a doubling.

State what the supplied observations or conditions establish, and separate that from any assumption.

Carbonate-system equilibria shift, often lowering carbonate ion availability and affecting saturation, depending on conditions.

The 26% calculation concerns[H⁺]; carbonate requires additional coupled-equilibrium information.

A known pH difference supports a hydrogen-ion ratio under the stated convention. It does not by itself determine carbonate concentration or a shell-dissolution rate. Alkalinity summarizes seawater’s acid-neutralizing charge account and helps constrain carbonate chemistry alongside dissolved inorganic carbon and conditions. Saturation state compares chemical conditions with mineral equilibrium. Keep these distinct quantities rather than converting a 26% hydrogen-ion increase directly into 26% carbonate loss or 26% biological harm.

The 26% calculation concerns[H⁺]; carbonate requires additional coupled-equilibrium information.

Response criteria

• Interpret labels, structures, axes, units and directions correctly.
• Explain the physical or environmental relationship or mechanism.
• Respect stated assumptions and distinguish observation from inference.

[H⁺] increases by 10^0.2≈1.585, about 58.5%. It does not prove the same carbonate decrease; alkalinity, dissolved carbon and coupled-equilibrium conditions are also required.

[H⁺] increases by 10^0.2≈1.585, about 58.5%.

It does not prove the same carbonate decrease; alkalinity, dissolved carbon and coupled-equilibrium conditions are also required.

Response criteria

• Use the stated measurements or conditions, with correct units.
• Connect the result to the physical or environmental mechanism or evidence relationship.
• Identify the assumption, model limit or further evidence requested.

Write the relationship first; substitute with consistent units.

0.2 °C/decade

.6/30×10=.2.

Its spatial and temporal scope is narrower than the long-term global statistical question.

Response criteria

• State a scientifically accurate conclusion.
• Show the calculation or mechanism that supports it.
• Include units, conditions, or limits where relevant.

List the given quantities, select a relationship, and check units before substituting.

0.2 °C/decade

.8/40×10=.2.

Projections depend on future scenarios and models; observations describe measured past/current conditions.

Response criteria

• State a scientifically accurate conclusion.
• Show the calculation or mechanism that supports it.
• Include units, conditions, or limits where relevant.

Data coverage, baseline and uncertainty affect interpretation.

0.15×3=0.45°C.

State what the supplied observations or conditions establish, and separate that from any assumption.

They compare deviations relative to a reference, reducing effects of different absolute local temperatures; the baseline must be clear.

No. It measures a different aspect of the energy system and provides complementary evidence with its own coverage and uncertainty.

A global estimate combines observations with stated spatial coverage and analysis methods. Coverage bias can arise when sampled places differ systematically from missing places; measurement changes and calibration also require assessment. Independent datasets and indicators help test whether an apparent trend is an artifact of one method, although they need not measure exactly the same physical quantity. Do not invent a station-level error bar from the annual global values alone; use the source’s uncertainty methods.

No. It measures a different aspect of the energy system and provides complementary evidence with its own coverage and uncertainty.

Response criteria

• Interpret labels, structures, axes, units and directions correctly.
• Explain the physical or environmental relationship or mechanism.
• Respect stated assumptions and distinguish observation from inference.

Original anomalies are 0.6 and 1.0°C; new anomalies 0.4 and 0.8°C. The difference remains 0.4°C, so a uniform baseline shift changes offset rather than physical change.

Original anomalies are 0.6 and 1.0°C; new anomalies 0.4 and 0.8°C.

The difference remains 0.4°C, so a uniform baseline shift changes offset rather than physical change.

Response criteria

• Use the stated measurements or conditions, with correct units.
• Connect the result to the physical or environmental mechanism or evidence relationship.
• Identify the assumption, model limit or further evidence requested.