What percentage of global CO2 emissions today comes from land-use change versus fossil fuels?

1. Fossil fuels are the overwhelming source — the basic math

The Global Carbon Project’s 2025 figures project fossil‑fuel and cement CO2 at 38.1 GtCO2 and land‑use change at about 4.1 GtCO2, adding to roughly 42.2 GtCO2 total; that arithmetic places fossil sources at about 90% and land‑use change at about 10% of total CO2 in 2025 ^{[1] [2]}.

2. Why the headline split matters for climate policy

A 90/10 split refocuses policy on the energy and industrial systems: because fossil CO2 is the dominant share, the IPCC and analysts warn that deep cuts in fossil emissions are necessary to meet Paris targets and cannot be replaced by land‑use measures alone ^[5]. Climate trackers emphasise that while land sector mitigation helps, it does not substitute for rapidly phasing out fossil fuels ^[5].

3. Land‑use emissions are smaller but volatile and uncertain

Land‑use CO2 estimates are subject to larger uncertainty than fossil CO2 because they depend on forest carbon stocks, fires and modelling choices; recent years show a decline in land‑use emissions, with 2025 projected near 4.1 GtCO2, lowering total emissions slightly compared to 2024 ^{[1] [2]}. Sources note that improvements in forest biomass and reduced deforestation in some regions contributed to the fall in land‑use emissions ^{[6] [1]}.

4. Decadal trends: the share is changing, slowly

Over recent decades the share of CO2 from land‑use has fallen as fossil emissions rose faster; Carbon Brief and other analyses point out that fossil CO2 has dominated the past 20 years and made up roughly 87–90% of CO2 in recent decades ^{[7] [3]}. That trend can reverse in scenarios where fossil emissions decline sharply and land‑use emissions stay positive, which is why some researchers warn land measures will grow in relative importance in future mitigation mixes ^[7].

5. Sinks, not just sources — the role of land and oceans

Reports accompanying the Global Carbon Budget note that natural sinks (land and ocean) absorb a substantial fraction of anthropogenic CO2; the land sink recovered from El Niño effects by 2025, moderating atmospheric accumulation even as fossil emissions hit a record ^{[2] [6]}. However, independent research cited by the budget suggests climate change has weakened sinks over the past decade, complicating the net picture ^[8].

6. Different inventories, different framings — watch the definitions

“CO2 from land‑use change” in these datasets refers to net emissions from activities like deforestation, degradation and regrowth; fossil CO2 includes coal, oil, gas and cement production ^{[1] [9]}. Some datasets and policy tools exclude LULUCF (land‑use, land‑use change and forestry) from core effort‑sharing metrics, reflecting methodological and policy choices about what counts toward targets ^[5].

7. Competing perspectives and remaining limits in the reporting

Most sources (Global Carbon Project, Carbon Brief, BBC, Eco‑Business, CSIRO) converge on the 38.1 GtCO2 vs ~4.1 GtCO2 split for 2025 and the ~90/10 ratio ^{[1] [2] [3] [4] [6]}. Limitations remain: land‑use numbers have wider uncertainty ranges and methodological differences across groups; available sources do not detail every country’s contribution to the land‑use share in 2025 or break down uncertainty intervals in full here ^{[9] [1]}.

8. Bottom line for readers: where effort must go

The empirical bottom line reported across the Global Carbon Budget and media coverage is clear: most CO2 emitted today comes from burning fossil fuels and cement production (≈38.1 GtCO2, ~90%), while land‑use change contributes a smaller but still meaningful portion (≈4.1 GtCO2, ~10%) — so global mitigation must prioritize rapid fossil‑fuel reductions while also maintaining land‑use reforms and sink protection ^{[1] [2] [5]}.