Quick answer: COP21, the Paris Agreement and where the UK stands
- Warming so far
- 1.3°C
- Above pre-industrial, 2024 average
- Paris target
- <2°C
- Aim 1.5°C
- Current trajectory
- ~2.7°C
- 2100 on current policies
- UK 2030 target
- -68%
- vs 1990. Achieved so far: ~-50%
What COP21 actually agreed
COP21 ran from 30 November to 12 December 2015 at Le Bourget, Paris, the 21st annual meeting of the Conference of the Parties (COP) to the UN Framework Convention on Climate Change (UNFCCC). It produced one document, the Paris Agreement, and 196 parties have since signed it. The UK ratified it in November 2016.
The Agreement is short, around 25 pages. Four parts of it carry almost all the weight.
1. The "well below 2°C" language
Article 2 commits parties to "holding the increase in the global average temperature to well below 2°C above pre-industrial levels, and pursuing efforts to limit the temperature increase to 1.5°C". That clause does the heavy lifting. The 2°C ceiling came in mostly through European pressure. The 1.5°C aim was pushed by small island states, who would lose their land at 2°C. Both numbers are in there, but only one is the legal target.
2. Nationally Determined Contributions
Every party submits an NDC, a Nationally Determined Contribution. Think of it as each country's homework, resubmitted every five years. The NDC says what the country will cut, by when, and how it will measure progress. The country sets its own level, hence "nationally determined". Nobody can be forced to set a particular target.
3. The ratchet mechanism
Each new NDC must be more ambitious than the last. A country cannot regress. This is the "ratchet": pledges only tighten. It is the only structural pressure the Agreement applies, and it is real, even if slow.
4. The global stocktake
Every five years, parties collectively review progress. The first global stocktake concluded in 2023 at COP28 in Dubai. Its headline finding was unambiguous: the world is not on track for 1.5°C, and existing pledges are not enough either. The next stocktake is due in 2028.
What this means in practice. The Paris Agreement is more like a gym membership than a contract. The binding part is showing up (submitting NDCs, reporting honestly, attending stocktakes). The results, getting fitter or losing weight, are not enforceable.
Why most coverage gets COP21 wrong
Three myths show up in nearly every consumer write-up of the Paris Agreement. None survives a careful read of the text.
- 1"The Paris Agreement caps warming at 1.5°C." The legal target is "well below 2°C". 1.5°C is the aspiration, not the ceiling;
- 2"The Agreement is legally binding on emissions." Only the process is binding. Countries that miss their targets face no penalty under the Agreement itself;
- 3"196 countries committed to net zero in Paris." Net zero was not in the Paris text. It became the default policy framing later, mostly between 2018 and 2021.
Why the gap? Because the framing that "we fixed climate change in Paris" was politically useful at the time. Ten years on, that framing makes it harder to see how far the trajectory still has to bend.
The 1.5°C vs 2°C choice, in plain numbers
Half a degree sounds small. It is the gap between a mild UK winter and a hot one. The IPCC's Special Report on 1.5°C (2018) and AR6 (2021 to 2023) quantified what changes between 1.5°C and 2°C of warming. The numbers are blunt.
| Impact | At 1.5°C | At 2°C |
|---|---|---|
Sea level rise by 2100 Affects UK coastal flooding risk |
~0.43 m | ~0.55 m |
Population exposed to severe heat once every five years UK summer heatwaves get more frequent |
~14% of world | ~37% |
Coral reefs lost A 2°C world loses essentially all of them |
~70 to 90% | >99% |
Risk of an ice-free Arctic summer Drives UK winter jet stream changes |
Once per century | Once per decade |
Crop yield losses (wheat, maize, rice, soy) Food import prices rise in the UK |
Moderate | Roughly double |
Source: IPCC Special Report on 1.5°C (2018) and AR6 Working Group II (2022). Central estimates, rounded.
Why this matters for a UK reader. The UK is a high-latitude island. We get less direct heat-stress damage than Mediterranean countries, but we are very exposed to sea level rise (the Thames Estuary, East Anglia) and to food and energy import prices. 1.5°C versus 2°C is not abstract: it changes how much we pay for a loaf of bread and how often the Thames Barrier closes.
What the UK signed up to
The UK was one of the first big economies to ratify the Paris Agreement, in November 2016. Domestic implementation runs through a framework that predates Paris: the Climate Change Act, passed in 2008, which sets legally binding emissions ceilings ("Carbon Budgets") and creates an independent watchdog, the Climate Change Committee (CCC).
The UK's NDC numbers
The current UK NDC has two milestones and a destination:
- By 2030: at least a 68% cut in greenhouse gas emissions versus 1990;
- By 2035: at least an 81% cut versus 1990 (updated NDC submitted late 2024);
- By 2050: net zero, meaning emissions no greater than the planet (and UK land and sea) can absorb.
These targets are tighter than the EU equivalent (-55% by 2030) but in the same neighbourhood as Germany and the Nordics. They are widely judged by the CCC as broadly consistent with a 1.5°C pathway, if (and only if) policy actually delivers them.
Carbon Budgets and the Climate Change Committee
Between the NDC milestones, the UK runs a system of five-yearly Carbon Budgets. The Climate Change Committee proposes each budget, Parliament passes it into law, and government must publish a plan to meet it. The Sixth Carbon Budget covers 2033 to 2037 and was set in 2021. The Seventh is due in 2025 to 2026.
The CCC publishes an annual Progress Report to Parliament grading the government on delivery. The 2024 report flagged that the UK met its Third Carbon Budget (2018 to 2022) comfortably, mostly because of the coal phase-out, but warned the Fourth and Fifth budgets are at risk without much faster action on home heating and transport.
Where the UK actually stands in 2026
As of 2024 provisional data, UK greenhouse gas emissions are about 50% below 1990 levels. That is among the deepest cuts of any G7 economy and roughly two thirds of the way to the 2030 target. The detail is more uneven.
Power: largely done
In 1990, coal generated about 65% of UK electricity. By 2024, coal was below 1% and the last coal power station, Ratcliffe-on-Soar, closed in September 2024. Renewables (wind, solar, biomass) now provide roughly 50% of generation, nuclear about 13%, and gas the remainder. Power-sector emissions are down more than 75% since 1990. This is the success story, and most of the UK's overall cut comes from it.
Transport: slow but moving
Transport overtook power as the UK's largest emitting sector in 2016 and is still on top. New petrol and diesel car sales are due to end in 2035 (originally 2030, pushed back in 2023). Electric vehicles passed 20% of new car sales in 2024. Aviation, freight and shipping are barely moving. Transport emissions are down about 10% since 1990, a fraction of what is needed.
Heat: the laggard
About 23 million UK homes use a gas boiler. The CCC says installations of heat pumps need to reach 600,000 a year by 2028 to stay on track. Actual installations in 2024 were around 60,000. New gas boiler sales were planned to end by 2035, but the policy is under review. Heat is now the single biggest reason the UK is judged off track for the 2035 NDC.
The plain summary. The UK has done the easy two thirds of decarbonisation, mostly by replacing coal with wind and gas. The remaining third, decarbonising home heating, heavy transport, industry and aviation, is harder, slower and more visible to households. That is where Paris-compatible policy now has to deliver.
Where are we on the Paris trajectory?
Pick a scenario. The widget shows the projected global temperature rise by 2100, what it means in plain terms, and what the UK specifically has to do under that scenario. Numbers come from UNEP Emissions Gap 2024 and IPCC AR6.
Pick a scenario
Toggles the focus from the global picture to what the UK has to do.
Projected 2100 warming
°C
vs pre-industrial, central estimate by 2100
Bar shows how far along the warming scale this scenario lands.
What COP21 means for your UK energy bill
Paris is not just an international agreement; bits of it show up on every UK energy bill. Here are the three lines where you can see it.
1. Renewable obligation and policy costs
For years, around 20% of a typical UK electricity bill was policy costs: the Renewables Obligation, Feed-in Tariff, Contracts for Difference (CfD) auctions, Warm Home Discount, and several smaller levies. From April 2026, the Autumn Budget 2025 moved a large share of these off the bill and into general taxation, worth about £130 a year for a typical home. The renewable build-out itself does not stop; only the funding route changed.
2. Network upgrades and the standing charge
A net-zero grid has to roughly double in size by 2050. New transmission lines, new substations, new offshore connections all cost money, and almost all of that cost lands on the daily standing charge rather than the unit rate. The Q2 2026 electricity standing charge is 57.2p a day, more than £200 a year before you switch anything on. Expect this line to keep rising even as the unit rate falls with cheaper renewables.
3. The carbon price
Every tonne of CO2 from a UK power station carries a price under the UK Emissions Trading Scheme (UK ETS). When the carbon price is high, gas-fired electricity costs more to produce, which feeds through to the wholesale price and eventually the cap. Paris-compatible policy is, mechanically, a higher carbon price over time. That hits gas use harder than electricity, which is why heat pumps look better on a Paris trajectory than on today's prices.
For a more current view of the price cap and where it goes next, see our explainer on the Ofgem price cap announcement and our cheapest electricity supplier guide.
Frequently asked questions
Switch to a tariff that matches your climate values
The household lever the Paris Agreement leaves you is real but narrow: choose a renewable electricity tariff, use less gas, and switch payment method if you can. Selectra UK helps compare green tariffs from across the market, with no fee to you, and can talk you through offsetting residual emissions if you want to.
Speak to a Selectra UK adviser on 020 3936 0059, Monday to Friday, 9am to 6pm.