How many degrees in temperature has the earth increased in time?
Executive summary
The best-available instrumental records and major scientific assessments show the planet’s average surface temperature has risen by about 1.0–1.2°C (≈1.8–2.2°F) since the late 19th century or the commonly used pre‑industrial baseline (mid‑1800s to 1900) — with human‑driven warming reaching roughly 1°C above pre‑industrial by the late 2010s (NASA, NOAA, IPCC, Imperial College) [1][2][3][4]. Short‑term spikes above that level (for example, daily reanalysis peaks reported by Copernicus) do not change the long‑term global average but underscore variability and measurement differences [5].
1. What the headline number means: about one degree and why that is significant
Multiple independent global temperature datasets and reviews — including NASA’s GISS analysis, NOAA summaries, the IPCC and academic institutions — converge on a long‑term warming of roughly 1°C since the pre‑industrial era or since consistent instrumental records began in the mid‑to‑late 19th century, which scientists treat as a meaningful increase in heat energy circulating through the climate system [1][2][3][4].
2. Different baselines, slightly different numbers — sources of the spread
The exact figure depends on which baseline and dataset are used: NOAA measures about a 1.0–1.46°C rise relative to 1850–1900 depending on the comparison year and decade averages [2], NASA reports “a little more than 1°C” since 1880 [1], Imperial College notes about 1.1°C since ~1850 [4], and the IPCC frames human‑induced warming as reaching 1°C around 2017 with an uncertainty band tied to definition and methods [3]. Scholarly debate over what constitutes “pre‑industrial” (mid‑1700s, 1850–1900, or another window) and how to blend sparse early measurements produces modest differences in estimates [6][7].
3. Rates and recent acceleration: faster warming now than a century ago
Long‑term averages mask changing speed: scientists report an average warming rate of roughly 0.06–0.07°C per decade since the late 19th century in some summaries [8][9], while the IPCC and NOAA highlight a faster recent pace — about 0.2°C (±0.1°C) per decade in IPCC assessments and higher decadal rates since the 1980s — meaning the last decades account for most of the observed increase [3][2].
4. Single‑day or regional exceedances versus global mean — why the 2°C headlines caused confusion
Reanalysis products like ERA5 can show brief global surface‑air temperature anomalies that exceed 2°C above a pre‑industrial baseline on particular days, a finding reported by Copernicus, but these are instantaneous or short‑term anomalies rather than a new global long‑term average; they reflect weather, El Niño, and methodological differences rather than a permanent shift of the multi‑decadal mean [5]. Major