Title page 1

Contents 3

Foreword 4

Key indicator 5

Atmospheric carbon dioxide 5

Global mean near-surface temperature 7

Ocean heat content 9

Global mean sea level 11

Ocean pH 13

Glacier mass balance 15

Sea-ice extent 17

Climate driver - El Niño-Southern Oscillation 19

Global patterns oftemperature and precipitation 21

TEMPERATURE 21

PRECIPITATION 22

High-impact events 23

Monitoring global temperature for the Paris Agreement 25

Global mean surface temperature anomalies in 2023/2024: Towards understanding the influencing factors 27

Datasets and methods 29

List of contributors 35

Endnotes 38

Tables 30

Table 1. Global mean temperature anomalies for individual datasets for 2024 for four different baselines 30

Table 2. NSIDC values compared with EUMETSAT Ocean and Sea Ice Satellite Application Facility figures for 2024 32

Figures 5

Figure 1. Annual mean globally averaged atmospheric mole fraction of carbon dioxide from 1984 to 2023 in parts per million (ppm) 5

Figure 2. Annual global mean temperature anomalies relative to a pre-industrial (1850-1900) baseline shown from 1850 to 2024 7

Figure 3. Annual global ocean heat content down to 2000 m depth for the period 1960-2024, in zettajoules (10²¹ J). The shaded area indicates the 2-sigma... 9

Figure 4. Seasonal global mean sea level change from 1993 shown for 1993-2024. The seasonal cycle has been removed from thedata. The shaded area... 11

Figure 5. Annual global mean surface ocean pH 1985 to 2023. The dark line is the central estimate and the shaded area is the uncertainty range 13

Figure 6. Cumulative annual mass balance of reference glaciers with more than 30 years of ongoing glaciological measurements. Annual mass change values... 15

Figure 7. Monthly Arctic (left) and Antarctic (right) sea-ice extent anomalies (difference from the 1991-2020 average) in millions of square kilometres... 17

Figure 8. Typical El Niño seasonal precipitation effects for January to June based on various sources, see Datasets and methods. Note this is not a forecast;... 19

Figure 9. Annual average temperature anomalies relative to the 1991-2020 average. The values shown are the median of six global temperature datasets 21

Figure 10. Annual precipitation 2024 expressed as percentiles of the 1991-2020 distribution. Brown areas are unusually dry. Green areas are unusually wet 22

Figure 11. Three methods for establishing an up-to-date estimate of current global warming as of 2024, compared with theIPCC AR6 method,... 26

Figure 12. (a) Annual global mean temperature. Estimates of relative temperature residuals for (b) 2023 and (d) 2024 attributable to ENSO and four distinct forcings... 27