Emissions gap

Geography glossary

Also called: UNEP Emissions Gap Report · Topic: Climate Change: Causes, Evidence and the Global Response · NCERT: Beyond NCERT

Meaning

The emissions gap is the difference between two numbers: the greenhouse gas emissions the world is expected to release in a future year (such as 2030) if countries carry out their climate pledges (NDCs), and the lower level needed in that year to stay on a path that limits warming to 1.5 °C or well below 2 °C. The United Nations Environment Programme (UNEP) measures it every year in its Emissions Gap Report.

It matters because it shows in one number how far current pledges fall short of the Paris Agreement goals. It is also the starting point for debates on ambition, overshoot and climate justice.

Explanation

How the gap is worked out

Step 1: add up the pledges.
Each country sends an NDC (Nationally Determined Contribution), which is its own climate pledge under the Paris Agreement. A new one is due every five years, and each should be stronger than the last (the "ratchet").
UNEP adds up what these pledges mean for global emissions in a target year.
Step 2: find the safe level.
Climate models show how much the world can emit in that year and still keep warming to 1.5 °C or 2 °C.
Step 3: subtract.
Pledged emissions minus safe emissions gives the gap.
It is measured in GtCO2e (billion tonnes of CO2-equivalent). That unit puts methane, nitrous oxide and other gases on the same scale as CO2.
Example: UNEP's 2022 report found that even if all unconditional NDCs were fully carried out, the gap to the 1.5 °C scenario would be 23 GtCO2e (range 20–24).

Parts and types of the gap

By pledge type:
Unconditional NDCs are what a country promises to do on its own. The 23 GtCO2e figure uses these.
Conditional NDCs are extra cuts a country will make only if it gets outside finance or technology. Because they are bigger promises, they give a smaller gap.
By temperature goal: the 1.5 °C gap is always larger than the 2 °C gap, because the 1.5 °C path needs deeper cuts.
As a warming figure: UNEP also turns pledges into the warming they would cause by 2100. Its 2025 report projected 2.3–2.5 °C if NDCs were fully carried out, down from 2.6–2.8 °C in the previous edition.
Of that 0.3 °C fall, 0.1 °C came only from changes in the calculation method.
The expected US exit from the Paris Agreement will cancel another 0.1 °C.
That leaves only about 0.1 °C of real gain from the new pledges.

What the gap now tells us: the move to overshoot

The IPCC agrees the gap exists. The IPCC AR6 Synthesis Report (2023) found a substantial "emissions gap" between the 2030 emissions implied by NDCs and the modelled pathways that limit warming to 1.5 °C with no or limited overshoot.
The window has now closed.
UNEP's 2026 report, The Point of Return, says the chance of limiting warming to 1.5 °C with no or limited overshoot has been lost.
UNEP's 2025 report said a multi-decade average above 1.5 °C is very likely within the next decade.
"Overshoot" means passing 1.5 °C in the near term and coming back down to it by the end of the century.
Closing the gap now means limiting the overshoot.
UNEP says cuts of 26% by 2030 and 46% by 2035 would hold the overshoot to about 0.3 °C.
Even the lowest-overshoot scenario still available relies on storing about 320 GtCO2 over this century through carbon dioxide removal, or CDR (taking CO2 out of the air and storing it).
UNEP calls the methods needed for a return by 2100 uncertain, risky and costly.
Conditions needed to close the gap:
stronger NDCs, followed by real delivery, not just pledges
finance for developing countries, so that they can make early cuts
a smaller later reliance on CDR, which may not work at that scale

Where it occurs

Global: the gap is calculated for the whole world against the Paris Agreement goals. The Paris Agreement was adopted at COP21 on 12 December 2015 and came into force on 4 November 2016. It aims to keep warming "well below 2 °C" and to try for 1.5 °C.
Who publishes it: UNEP, every year. UNEP also helped WMO set up the IPCC in 1988. Recent editions:
The Closing Window (2022): 23 GtCO2e gap
the 2025 edition: 2.3–2.5 °C of warming if NDCs are fully carried out
The Point of Return (2026): 1.5 °C with no or limited overshoot is no longer possible
Where it is used:
at the yearly COPs under the UNFCCC, including COP31, which opened in Antalya, Türkiye, on 9 November 2026
in the Global Stocktake, the five-yearly review of progress under Article 14 of the Paris Agreement. The first ended at COP28 in Dubai (2023), and the next is in 2028.
India: India's own pledges count towards the global total.
updated NDC (August 2022): a 45% cut in emission intensity of GDP from 2005 levels by 2030, and about 50% of power capacity from non-fossil sources
Panchamrit (COP26, 2021): 500 GW of non-fossil capacity by 2030 and net zero by 2070
India argues that it contributed only about 4% of cumulative global emissions (all emissions added together over time) from 1850 to 2019, while it has about one-sixth of humanity
USA: its exit from the Paris Agreement directly widens the gap, cancelling about 0.1 °C of the projected improvement.

Don't confuse with

Carbon budget: this is a total amount of CO2 that can still be emitted for a warming limit. AR6 gave 500 GtCO2 from the start of 2020 for a 50% chance of 1.5 °C. The emissions gap is a one-year shortfall (for example, in 2030) between pledged and needed emissions. A budget is a stock, and the gap is a yearly difference.
Overshoot: this describes a temperature path (passing 1.5 °C and coming back by 2100). The emissions gap is about emissions. A large gap that does not close leads to overshoot.
IPCC reports: the Emissions Gap Report comes from UNEP, not the IPCC. The IPCC also mentions an emissions gap in AR6, but it does no research of its own and only assesses the science.
Emission intensity: India's 45% target is about emissions per unit of GDP, so total emissions can still rise. The emissions gap is always worked out in total emissions (GtCO2e).

Prelims Hooks

The Emissions Gap Report is published every year by UNEP, not by the IPCC, the UNFCCC or WMO.
UNEP's 2022 report put the unconditional-NDC gap to 1.5 °C at 23 GtCO2e (range 20–24).
UNEP's 2025 report: full NDC delivery leads to 2.3–2.5 °C of warming, down from 2.6–2.8 °C. Of that fall, 0.1 °C came only from changes in method.
UNEP's 2026 report is titled The Point of Return. It says 1.5 °C with no or limited overshoot is no longer possible.
Cuts of 26% by 2030 and 46% by 2035 would hold the overshoot to about 0.3 °C.
Trap: "The emissions gap equals the remaining carbon budget." FALSE. The gap is a yearly shortfall in emissions, while the budget is a total amount of CO2.

Mains Points

Pledge versus delivery (GS-III, environment): the gap keeps showing that NDCs are not enough.
Better headline numbers can hide very little real progress: only about 0.1 °C of the 0.3 °C improvement came from stronger pledges.
Because the 1.5 °C path with no or limited overshoot has been lost, the task now is to limit how high and how long the overshoot goes. The IPCC says risks grow with both.
Climate justice and CBDR-RC (GS-II/III): the gap is one global figure that does not say who caused it.
Under CBDR-RC (common but differentiated responsibilities and respective capabilities), those who polluted more and can afford more should do more.
India uses its low historical share (about 4% of cumulative emissions from 1850 to 2019) to argue that rich countries should close more of the gap and pay for it.
India asks that developed countries' climate finance should reflect their share of cumulative global emissions.
Finance and removals as the way to close it (GS-III): early cuts need money now.
India objected to the NCQG adopted at COP29 (the climate finance target), saying it goes against equity and CBDR-RC.
Leaving the gap open pushes the work onto later carbon removal of about 320 GtCO2, using methods UNEP calls uncertain, risky and costly.

Climate Change: Causes, Evidence and the Global Response