Every technical term used in Weekly Lesson One. Search, then use Back to return to the exact spot you left in the lesson. "Appears in" links take you to where each term is used.
Risk from sudden climate-related events such as floods, heatwaves and storms.
Adjusting systems to reduce harm from climate impacts already occurring or expected.
The principle that an emission reduction would not have occurred without the climate finance or carbon credit.
Tiny airborne particles (soot, dust, sulphates) that can reflect sunlight and cool the climate.
The fraction of sunlight a surface reflects.
Emissions that would have happened but are prevented, for example by replacing coal power with solar. No CO₂ is taken out of the air.
The emission level that would have occurred without the project or intervention.
Fine soot from incomplete burning that warms the air and darkens snow and ice.
Carbon captured and stored by coastal ecosystems such as mangroves, seagrass and saltmarshes.
The level emissions are projected to reach if no additional climate action is taken; used as a reference point for targets.
The total amount of CO₂ that can be emitted while keeping warming below a given limit.
A tradable certificate representing one tonne of CO₂e reduced or removed, measured against a baseline and independently verified.
The continuous movement of carbon between the atmosphere, ocean, land and living organisms.
Total GHG emissions caused by an entity, expressed in CO₂e.
Actively taking CO₂ out of the atmosphere and storing it durably.
A natural system that absorbs more carbon than it releases, such as forests or oceans.
A system that releases more carbon than it absorbs, such as a deforested area.
Common but Differentiated Responsibilities and Respective Capabilities: the principle that high-emitting, wealthy countries bear greater responsibility for climate action and finance.
A potent short-lived greenhouse gas from livestock, rice, landfills and fossil fuel leaks.
Risk from long-term climate shifts such as sea-level rise and changing rainfall patterns.
The long-term average pattern of weather, typically assessed over about 30 years.
Long-term changes in the climate system: temperature, rainfall, extremes, ice and sea level.
Funding directed at reducing emissions or helping people and ecosystems adapt to climate impacts.
The potential for harmful outcomes for people, assets or systems due to climate-related hazards interacting with vulnerability and exposure.
The study of how Earth's climate system works, how it is changing and what changes are projected.
The long-term warming expected from a doubling of CO₂ concentrations; IPCC best estimate 3°C.
The largest single contributor to human-caused warming; mainly from fossil fuels and deforestation.
Carbon dioxide equivalent: a unit that expresses all greenhouse gases in terms of their CO₂ warming effect.
Gains beyond climate, such as cleaner air, jobs or biodiversity, delivered by an action that also addresses climate change.
A combination of hazards that together cause greater harm than each would alone.
A more ambitious NDC target contingent on receiving international finance and technology support.
The cost of physical assets destroyed or damaged, such as buildings, roads and crops.
How long removed carbon stays out of the atmosphere; geological storage is more durable than trees.
The difference between energy absorbed from the Sun and energy emitted to space; currently positive.
A verified decrease in GHG emissions compared with a baseline.
The relationship between energy Earth absorbs from the Sun and energy it emits back to space.
The additional warming caused by greenhouse gases added by human activity.
The presence of people, assets, livelihoods or ecosystems in places that climate hazards can affect.
Science that estimates how climate change altered the likelihood or intensity of a specific event.
The movement of carbon through living things (photosynthesis, respiration, decay) over years to decades.
A process that responds to an initial change and amplifies or reduces it.
Human-made fluorinated gases used in refrigeration and industry; some have extremely high GWPs.
Coal, oil and natural gas: compressed remains of ancient organisms storing millions of years of carbon.
The most widely used international standard for measuring and reporting greenhouse gas emissions, organised into Scopes 1, 2 and 3.
The long-term rise in Earth's average surface temperature caused mainly by the enhanced greenhouse effect.
Glacial lake outburst flood: a sudden flood caused when a lake dammed by ice or debris breaks through.
A gas that absorbs and re-emits infrared radiation, slowing heat loss to space.
Presenting an activity, product or investment as more climate-friendly than it really is.
Global warming potential: the ratio of heat trapped by a gas over a time horizon compared with CO₂.
A potentially damaging physical event or trend, such as a flood, heatwave, drought or rising sea level.
The network of rivers, barrages and canals that distributes Indus water to farms across Pakistan; one of the largest connected irrigation systems in the world.
Invisible heat energy emitted by warm objects, including Earth's surface.
Intergovernmental Panel on Climate Change: the United Nations body that assesses published climate science and summarises it for governments.
An amendment to the Montreal Protocol under which countries, including Pakistan, agreed to phase down hydrofluorocarbons (HFCs).
A natural cooling phase of the tropical Pacific that tends to strengthen South Asian rainfall.
When a project reduces emissions in one place but increases them elsewhere.
Harm from climate change that occurs despite both mitigation and adaptation efforts.
Changes in economic flows resulting from damages, such as lost income and reduced production.
Adaptation that reduces short-term vulnerability but increases long-term risk or shifts harm to others.
A type of transition risk: shifts in demand and supply chains that reduce the market for carbon-intensive products.
Reducing or preventing greenhouse gas emissions to limit future warming.
A seasonal reversal of winds that brings most of Pakistan's yearly rainfall in summer.
A long-lived greenhouse gas mainly from fertilisers and manure.
The warming produced by naturally occurring greenhouse gases, which keeps Earth habitable.
Nationally Determined Contribution: a country's plan under the Paris Agreement.
A change that causes Earth to lose more energy, leading to cooling.
The state where GHG emissions are balanced by removals, so net additions to the atmosphere are zero.
The decrease in ocean pH as CO₂ dissolves in seawater, harming marine life.
The 2015 international climate treaty under which countries aim to hold warming well below 2°C, pursue efforts to limit it to 1.5°C, and submit national climate plans (NDCs).
The point after which glacier meltwater contributions begin to decline as ice reserves shrink.
The risk that carbon stored in ecosystems is later released by fire, disease or land-use change.
The process by which plants use sunlight and CO₂ to produce organic matter, absorbing carbon.
Financial risk arising from the physical effects of climate change on assets, operations and supply chains; it can be acute or chronic.
A type of transition risk: new laws, taxes, standards or regulations that raise costs for high-emission activities.
A change that causes Earth to keep more energy, leading to warming.
Parts per million: the concentration unit used for greenhouse gases in the atmosphere.
The change in Earth's energy balance caused by a factor, measured in W/m² relative to 1750.
Energy from naturally replenishing sources (solar, wind, hydro) with no direct operational emissions.
A type of transition risk: damage to a company's brand from association with high emissions or climate inaction.
Categories of GHG emissions: direct (1), purchased energy (2), value chain (3).
The movement of carbon through rocks, soils and deep ocean sediments over millions of years; it formed today's fossil fuels.
Assets that lose value early because of climate-related policy, technology or market changes.
Task Force on Climate-related Financial Disclosures: a framework for reporting climate risks under four pillars (governance, strategy, risk management, and metrics and targets).
A type of transition risk: cleaner technologies displacing older equipment before it has paid for itself.
Risk arising from the shift to a lower-carbon economy: policy, technology, market and reputational.
An NDC target that a country commits to achieve using its own resources.
The degree to which a system is susceptible to harm and unable to cope with climate impacts.
Reliable access to enough safe water for people, agriculture, industry and ecosystems.
Atmospheric conditions at a specific place and time, varying over hours to days.
The calculations used in Weekly Lesson One. Each formula has a short explanation, a worked example and a calculator you can try. Use the Back button to return to the exact place you left in the lesson.
What it does: converts any greenhouse gas into the warming-equivalent amount of carbon dioxide, so that different gases can be added together and compared. Carbon dioxide itself has a GWP of 1.
Worked example (from Mini-Course 3): a dairy colony releases 50 tonnes of methane in a year. Using a 100-year GWP of 28: 50 × 28 = 1,400 tonnes CO₂e.
GWP values are revised from time to time and differ by time horizon (20-year or 100-year). Always state which values you used.
What it does: measures how much less a project emits than it would have without the intervention. The baseline is a credible estimate of "what would have happened anyway", so the result is only as good as the baseline.
Worked example (illustrative): a mill's credible baseline is 800 tonnes CO₂e a year; after switching to a cleaner boiler it emits 500 tonnes CO₂e. Reduction = 800 − 500 = 300 tonnes CO₂e a year.
For carbon credits, the reduction must also be additional, and any leakage must be deducted.
What it does: shows what is actually added to the atmosphere once removals are counted. Net zero is reached when the result is zero: remaining emissions are fully balanced by removals.
Worked example (illustrative): an organisation emits 500 tonnes CO₂e and removes 500 tonnes CO₂e through durable removals. Net emissions = 500 − 500 = 0, so it is at net zero even though it still emits.
What it does: turns a multi-year funding estimate into a yearly figure that can be compared with annual budgets and annual finance flows.
Worked example (illustrative): a programme needs USD 80 billion over 8 years. Average annual need = 80 ÷ 8 = USD 10 billion a year.
Published estimates of national needs are updated regularly. Use the latest official figure and count the years in its period carefully.
How to set up the Weekly Lesson One calculations in Microsoft Excel or Google Sheets. The numbers below are example values for practice only.
Every cell has an address made of its column letter and row number, such as B2. A formula always starts with =. Excel then calculates the result and updates it whenever an input changes.
=B2*C2 multiplies two cells=B2-C2 subtracts=B2/C2 divides=SUM(D2:D5) adds a range of cellsPut each gas on its own row with its mass and GWP, then multiply. Links to Formula 1.
| A | B | C | D | |
|---|---|---|---|---|
| 1 | Gas | Mass (t) | GWP | CO₂e (t) |
| 2 | Methane | 50 | 28 | =B2*C2 |
| 3 | Nitrous oxide | 3 | 265 | =B3*C3 |
| 4 | Carbon dioxide | 300 | 1 | =B4*C4 |
| 5 | Total | =SUM(D2:D4) |
Tip: type the formula once in D2, then drag the small square at the bottom-right corner of the cell down to copy it. Excel changes the row numbers for you.
Links to Formula 2.
| A | B | C | D | |
|---|---|---|---|---|
| 1 | Year | Baseline (t CO₂e) | Project (t CO₂e) | Reduction |
| 2 | Year 1 | 800 | 500 | =B2-C2 |
| 3 | Year 2 | 800 | 450 | =B3-C3 |
| 4 | Total | =SUM(D2:D3) |
If every row should use the same GWP stored in one cell (say F1), write =B2*$F$1. The $ signs stop Excel from moving that reference when you copy the formula down. This is called an absolute reference.
Links to Formula 4. With the total need in B2 and the number of years in C2:
=B2/C2 gives the average per year=ROUND(B2/C2,1) rounds it to one decimal place#VALUE!: a cell contains text instead of a number. Retype the number without units such as "t" or "USD".#DIV/0!: you divided by an empty cell or zero. Check the number of years.SUM() includes every row.