Question 1

What is a carbon offset and do they actually work?

Accepted Answer

A **carbon offset** is a credit representing one tonne of CO₂ either removed from the atmosphere or prevented from being emitted somewhere else, bought to compensate for emissions you produced.

**The types differ enormously in quality:**

**Avoidance offsets** claim emissions did not happen — forest protection, renewable projects replacing fossil generation, methane capture.

**Removal offsets** take carbon out — reforestation, soil carbon, direct air capture, enhanced weathering.

**Four criteria decide whether an offset is real:**

**Additionality.** Would the project have happened anyway? A wind farm that was already commercially viable does not become additional because someone bought credits from it. This is the single biggest failure point, and it is inherently hard to prove because it requires a claim about a counterfactual.

**Permanence.** Carbon in a tree returns to the atmosphere if the forest burns, is logged, or dies. Geological storage lasts; biological storage is a lease, not a purchase.

**Leakage.** Protecting one forest can displace logging to the next valley, achieving nothing overall.

**Accurate baselines.** Deforestation avoided is measured against a predicted rate of loss. Inflate the prediction and you generate credits for nothing.

**What investigations have found.** Several major journalistic and academic investigations, particularly into REDD+ forest-protection credits, have concluded that a large proportion of examined credits from some registries did not represent real reductions, primarily through inflated baselines. Standards bodies have since revised methodologies, and the market has contracted.

**Where offsets are defensible:** for genuinely unavoidable residual emissions, after reduction has been exhausted — and preferably durable removals rather than cheap avoidance credits.

**Where they are not:** as a substitute for reducing emissions. The mitigation hierarchy is avoid, reduce, then offset what remains. Buying credits instead of cutting is the definition of greenwashing, and advertising regulators in several countries have ruled against "carbon neutral" claims resting on weak offsets.

Price is a useful signal: credible removal costs far more than a few pounds a tonne.

Question 2

What is carbon capture and storage, and does it work?

Accepted Answer

Capturing carbon dioxide and putting it underground permanently. The technology demonstrably works; the contested questions are cost, scale, and whether its availability delays cutting emissions in

Question 3

What is a carbon sink, and how much CO₂ do the oceans absorb?

Accepted Answer

A carbon sink is any reservoir absorbing more carbon than it releases. The two dominant natural sinks are the ocean and land vegetation and soils, and together they absorb roughly half of human CO₂

Question 4

What is blue carbon?

Accepted Answer

Carbon captured and stored by coastal and marine ecosystems — principally saltmarsh, mangroves and seagrass — which sequester carbon at rates far exceeding most terrestrial habitats, per unit area.

Question 5

What is a carbon border adjustment mechanism?

Accepted Answer

A carbon border adjustment mechanism (CBAM) charges imports according to the emissions produced making them, so that goods from countries with weaker climate policy do not undercut domestic producers

Question 6

What is the difference between a carbon tax and an emissions trading scheme?

Accepted Answer

Which variable is fixed. A carbon tax fixes the price and lets emissions find their level; a trading scheme fixes the quantity of emissions and lets the price find its level. Both put a cost on

Question 7

How much of climate change comes from food and farming?

Accepted Answer

Roughly a quarter to a third of global greenhouse gas emissions depending on what is counted — and the distinctive feature is that these emissions are mostly not carbon dioxide from burning fuel,

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