Features of the surface temperature regime over the Globe in 2024. Current status of global warming

Abstract

This study presents an analysis of surface temperature conditions
over the Globe in 2024, along with long-term variability 1850-2024 (with a focus
on the state of global warming). Four datasets are used: the IGCE basiс dataset
(T3288, land-only), and UK datasets (CRUTEM5 (land), HadSST4 (sea only),
HadCRUT5 (land + sea)). All time series were updated through December 2024
and expressed as anomalies relative to the 1991-2020 reference period.
Results indicate that 2024 became the warmest year on record (since 1850).
The global annual anomaly of near-surface temperature reached in 2024 +0.593°C.
This value exceeds the 2023 record by 0.06°C and surpasses the pre-industrial
(1850-1900) baseline by 1.437°C. A continuous sequence of monthly global
records lasted for 14 consecutive months, from May 2023 through June 2024 and
more than half of all observation stations (53%) recorded extreme annual values of
temperature in 2024, exceeding the 95th percentile (5% heat extremes). Local trend
estimates for 1976-2024 confirm the warming tendency with high confidence: 97%
of all estimates are positive. The highest intensity of warming is observed on
average in the Arctic latitudinal belt (+0.56°C per decade) and in Europe (+0.59°C
per decade).

Two distinct periods of warming can be traced in the 20th and 21st centuries:
from the 1910s
to the mid-1940s
(warming of Arctic) and the modern, from the
mid-1970s
(global warming). These periods are separated by non-directional
fluctuations with weak downward trends from 1940 to 1975. According to linear
trend estimates, the modern warming (1976-2024: +0.193°C per decade) is
somewhat stronger than the Arctic warming (1911-1945: +0.140°C per decade) and
in the period 1940-1975, the trend was close to zero. Global warming (1976-2024)
has proceeded almost twice as fast over land as on ocean aquatories, and has been
about twice as strong in the Northern Hemisphere compared to the Southern
Hemisphere (1.8 times stronger in ocean areas).
It is shown that a statistically significant upward trend in global surface
temperature occurs on any time interval from 10 to 100 years (within the period
1901-2024), ending no earlier than the mid-1970s
. In our opinion, this trend means
namely the “modern global warming”, whose active phase began in the mid-1970s
and continues to this day.
In conclusion, modern global warming is a well-established fact; it began in
the early 1970s
in the oceans of the Southern Hemisphere, became global in the
1990s
, intensified first in the 2000s
, then in the 2010s
, and continues into the
present. The most intense warming is observed on the continents of the Northern
Hemisphere. Processes occurring in the Southern Hemisphere ‒ particularly in
southern polar and mid-latitude regions ‒ warrant increased attention as potential
indicators of upcoming weakening of global warming.