Global warming
Executive summary
Global warming is intensifying: 2025 is on track to be the second or third warmest year on record and the past 11 years (2015–2025) are the warmest in the 176‑year observational record, with January–August 2025 averaging about 1.42°C above pre‑industrial levels (WMO and related analyses) [1]. Multiple assessments — WMO, UNEP’s Emissions Gap Report, Climate Central and independent trackers — say warming continues to accelerate, sea level rise and ocean heat content are at record highs, and current national pledges still leave the world headed well beyond 1.5°C without much change in the outlook [1] [2] [3] [4].
1. A planet running hot — the current record and trends
Global temperature records compiled by WMO and reporting groups show 2025 set to be the second or third warmest year on record, with the mean near‑surface temperature in January–August 2025 about 1.42°C ± 0.12°C above pre‑industrial levels; the last 11 years will be the warmest in the observational record [1]. Carbon Brief and other data syntheses confirm the first half of 2025 delivered multiple months among the top three warmest on record and place global surface temperature around 1.4°C above pre‑industrial levels [5] [6].
2. Drivers: greenhouse gases, ocean heat, aerosols and El Niño/La Niña
Scientists identify rising concentrations of heat‑trapping gases and record ocean heat content as central drivers; WMO notes greenhouse gas concentrations and ocean heat content reached record levels in 2024 and continued to rise into 2025, while changes in aerosols and natural variability (the end of a prolonged La Niña and prior El Niño phases) also affected recent year‑to‑year changes [1]. WMO’s decadal update forecasts annual mean near‑surface temperatures between 1.2°C and 1.9°C above 1850–1900 for 2025–2029 and gives an 86% chance that at least one year in that window will exceed 1.5°C [7].
3. Impacts already visible: seas, ice, reefs and weather extremes
Observed impacts track the warming: sea‑level rise has accelerated, nearly doubling its satellite‑era rate from ~2.1 mm/yr (1993–2002) to ~4.1 mm/yr (2016–2025) with 2024 a record year for global mean sea level; Arctic and Antarctic sea ice reached record lows in parts of 2025 and coral bleaching events have been unusually widespread, with one NOAA assessment calling the 2023–2025 bleaching event the largest to date [1] [8] [6]. Climate Central’s attribution work finds the signal of carbon pollution influenced unusually warm winter temperatures nearly worldwide in late 2024–early 2025 [4].
4. Where projections say we’re headed: 1.5°C likely to be exceeded soon
UNEP’s Emissions Gap Report 2025 models that global temperatures will likely exceed 1.5°C above pre‑industrial levels within the next decade and finds that even with new pledges the century‑end warming is projected at roughly 2.3–2.5°C under full NDC implementation and about 2.8°C under current policies [2] [3]. Climate Action Tracker and other evaluators show little measurable improvement in global warming projections over recent years, warning the gap between current policy and 1.5°C pathways remains large [9].
5. Policy and choices: pledges, emissions and the “virtually exhausted” budget
Analyses compiled in 2025 put the remaining carbon budget for a likely 1.5°C limit at vanishingly small levels: AAAS reported the budget is “virtually exhausted,” equivalent to only a few years at 2025 emission rates [8]. UNEP and others say limiting warming to 1.5°C requires rapid, deep cuts—emissions peaking by 2025 and falling roughly 43% by 2030 in their scenarios—and that current NDCs have only slightly moved the needle [3] [2].
6. Competing perspectives and scientific framing
There is consensus among the cited organizations (WMO, UNEP, Climate Central, Carbon Brief) that human emissions are the dominant long‑term driver and that impacts are already evident [1] [4] [2] [5]. Differences are about framing and timescales: some emphasize that single years should not define long‑term targets and that decadal averages matter for assessing whether 1.5°C is “breached” in a sustained way (UNEP notes yearly exceedances can occur but long‑term averages are the standard) [2]. Projections vary by scenario and methodology: WMO’s probabilistic windows for 2025–2029 are wide (1.2–1.9°C) while UNEP and CAT focus on policy gaps and end‑century outcomes [7] [3] [9].
7. What this means for readers: risks, choices and uncertainty
The near‑term science is unequivocal that warming, ocean heat and sea level are at or near record highs and that human emissions are the central cause [1] [4]. Available reporting also makes clear that whether warming stabilizes near 1.5°C or moves decisively toward 2–3°C depends on immediate, deep policy action that the latest pledges so far do not guarantee [3] [2]. Uncertainties remain about the timing of natural variability and how fast ice‑sheet and tipping‑point feedbacks will respond, but the cited reports underscore the narrow window for mitigation and the growing urgency for adaptation finance and planning [7] [3].
Limitations: this analysis uses only the supplied sources; available sources do not mention some contested claims sometimes seen in public debate (for example, specific recent national emissions figures or the U.S. withdrawal timing beyond what UNEP notes) and therefore those items are not addressed here (not found in current reporting).