State of the climate: Global temperatures throughout mid-2023 shatter records
The first three quarters of 2023 has seen unrenowned heat globally, putting 2023 on track to be the warmest year since records began in the mid-1800s, and likely for millennia before as well.
The past four months, in particular, have far exceeded any prior records, with September smashing the prior record by virtually 0.5C.
In this latest “state of the climate” quarterly update, Stat Brief finds:
- June, July, August, September and (very likely) October were the warmest respective months since records began.
- 2023 is now virtually certain to be the hottest year on record globally.
- A strong El Niño is expected to persist until mid-2024 in the majority of El Niño Southern Oscillation (ENSO) forecast models.
- October is likely to be extremely warm based on daily data so far, though not quite as unusual as September.
- While the unrenowned warmth of the last few months is primarily driven by a strong El Niño on top of human-driven warming, other contributing factors include an uptick in the 11-year solar cycle, an unusual volcanic eruption last year and a 2020 phaseout of planet-cooling sulphur dioxide in marine shipping fuels.
- Ocean heat content set a new record in September and has increased substantially over the past 12 months.
- Antarctic sea ice has been uncommonly far unelevated the prior record low for the past six months, while Arctic sea ice remains at the low end of the historical range.
- Global temperatures are closely aligned with the projections from climate models.
Global temperatures have soared in recent months
After a tomfool start due to an unusually persistent “triple dip” La Niña event, global temperatures have soared in recent months driven by rapidly growing El Niño conditions.
This short-term natural variability builds on top of the roughly 1.3C warming that has occurred since the mid-1800s due to human emissions of CO2 and other greenhouse gases.
The icon unelevated shows how global temperature so far in 2023 (black line) compares to each month in variegated years over the prior decade (coloured lines) in the Berkeley Earth surface temperature dataset.
Temperatures for each month from 2015 to 2023 from Berkeley Earth. Anomalies plotted with respect to a 1850-99 baseline. Chart by Stat Brief.
Every month from June onward this year has set a well-spoken record, with July, August and September shattering prior records by at least 0.3C (and virtually 0.5C in the specimen of September). The unrenowned summer warmth ways that it is now virtually certain that 2023 will be the warmest year on record.
In this latest quarterly state of the climate assessment, Stat Brief analysed records from five variegated research groups that report global surface temperature records: NASA’s GISTEMP; NOAA’s GlobalTemp; Hadley/UEA’s HadCRUT5; Berkeley Earth; and Copernicus/ECMWF.
The icon unelevated shows the yearly temperatures from each of these groups since 1970, withal with the stereotype over the first nine months of 2023. (Note: at the time of writing, September data was not yet misogynist for the Hadley/UEA record.)
Annual global midpoint surface temperatures from NASA GISTEMP, NOAA GlobalTemp, Hadley/UEA HadCRUT5, Berkeley Earth and Copernicus/ECMWF (lines), withal with 2023 temperatures to stage (January-September, coloured shapes). Each series is aligned by using a 1981-2010 baseline, with warming since pre-industrial based on HadCRUT5 values from the 1850-1899 to 1981-2010 periods. Chart by Stat Brief.
The globe as a whole has warmed virtually 1C since 1970, with strong try-on between variegated global temperature records. All show that year-to-date 2023 records are higher than any prior yearly record. However, there are larger differences between temperature records remoter when in time (particularly pre-1900) due to sparser observations and a resulting greater sensitivity to how gaps between measurements are filled in.
This year started out a bit on the colder side in all the variegated temperature records, with January only the seventh warmest January on record and February only the fourth or fifth warmest. March was the second warmest on record, April the fourth or fifth, and May the third warmest wideness all datasets.
However, from June onward each month has been unambiguously the warmest on record wideness all the variegated datasets. The respective rankings of each month in each dataset are shown below.
| GISTEMP | HadCRUT5 | NOAA | Berkeley | Copernicus | |
|---|---|---|---|---|---|
| Jan | 7th | 7th | 7th | 7th | 7th |
| Feb | 4th | 4th | 4th | 5th | 5th |
| Mar | 2nd | 2nd | 2nd | 2nd | 2nd |
| April | 4th | 4th | 5th | 4th | 5th |
| May | 3rd | 3rd | 3rd | 3rd | 3rd |
| June | 1st | 1st | 1st | 1st | 1st |
| July | 1st | 1st | 1st | 1st | 1st |
| Aug | 1st | 1st | 1st | 1st | 1st |
| Sept | 1st | TBC | 1st | 1st | 1st |
Rankings of 2023 global temperature by month wideness variegated datasets.
The unfurled strengthening of El Niño over the next few months ways that it is likely that this streak of record-setting warmth will continue.
The icon unelevated shows a range of variegated ENSO forecast models produced by variegated scientific groups. The values shown are sea surface temperature variations in the tropical Pacific – the El Niño 3.4 region – for three-month periods.
El Niño-Southern Oscillation (ENSO) forecast models for overlapping three-month periods in the Niño3.4 region (August, September, October – ASO – and so on) for the remainder of 2023 and then into the summer of 2024. Credit: Images provided by the International Research Institute for Climate and Society, Columbia University Climate School.
Virtually all models expect El Niño conditions to remain until early-to-mid 2024. Most models project a strong El Niño (>1.5C Niño 3.4 sea surface temperature – SST – anomaly), but relatively few expect a “super El Niño” (>2.5C) as strong as the world saw in 2015-16 or 1997-98.
Extreme heat worldwide
Record-setting global temperatures unsalaried to record heatwaves in many regions over the recent northern-hemisphere summer. The icon unelevated shows the parts of the world that saw record warm or unprepossessed temperatures over the first two-thirds of 2023 (January through to September) in the Berkeley Earth dataset.
Large parts of the North Atlantic saw record warm temperatures, as did the UK, large parts of Europe, the southern US and Mexico, Central America, South America, the Caribbean, Korea, Japan and China.
Notably, no zone on Earth saw record unprepossessed (or plane the second-to-fifth coldest temperatures on record).
Map of year-to-date (January-September) regions that set new records (warmest through to fifth warmest). Note that no regions set unprepossessed records for the year-to-date in 2023. Credit: Berkeley Earth
In September alone, 77 variegated countries – mostly in Europe and the tropics – set new monthly stereotype records.
Virtually everywhere on the planet saw warmer-than-usual temperatures for the year so far, with the exception of the western US, India and Greenland.
The tropical Pacific shows a strong foible “warm tongue” associated with El Niño over the first nine months of the year. The global temperature anomalies (changes) relative to the 1951-80 period used by Berkeley Earth are shown in the map below.
Map of year-to-date (January-September) global surface temperatures. Anomalies are shown relative to the 1951-1980 period pursuit the institute used by Berkeley Earth. Credit: Berkeley Earth.
October standing the record warm streak
While global temperature records are not yet in for the full month of October 2023, real-time reanalysis products increasingly indulge scientists to track global temperatures on a daily basis.
Reanalysis pulls together a huge value of data from satellites, weather balloons, aeroplanes, weather stations, ships and buoys to provide a detailed squint at how the Earth’s climate is waffly in real-time.
Modern reanalysis products, such as JRA-55 and ERA5, use state-of-the-art methods to produce records that uncurl well with traditional surface temperature datasets over recent decades.
In the icon below, Stat Brief shows the daily global temperature oddity values from the JRA-55 reanalysis product for each day since the record began in 1958 (grey lines). It shows the current year to stage (2023) in red and the prior record warm year, 2016, in blue. Nearly every single day since mid-June 2023 has been warmer than any prior days since the JRA-55 record began in 1958 – and, potentially, much remoter into the past.
Daily global midpoint surface temperature anomalies from the JRA-55 reanalysis product, using its standard 1991-2020 baseline period. Lines show global surface temperature anomalies for each day since the record began in 1958 (grey), the current year of 2023 to stage (red) and the previous record warm year in 2016 (blue). Chart by Stat Brief.
The heat map unelevated focuses on 2023, showing each day in the year, with columns representing each month. The red shading shows the temperature oddity of each day, with darker shading indicating increasingly lattermost temperatures. The map highlights how lattermost the prior four months (from July onward) have been compared to the prior period.
Daily global stereotype surface temperature anomalies for 2023 from the JRA-55 reanalysis product, using its standard 1991-2020 baseline period. Chart by Stat Brief.
With most of the data for the month of October now misogynist in the JRA-55 reanalysis product, Stat Brief estimates that October 2023 will be the warmest October on record, and is likely to exceed the prior record by at least 0.3C.
The icon unelevated shows Stat Brief’s estimate for October, with uncertainty intervals estimates based on the historical relationship between the first 19 days of the month misogynist at the time of publication and the overall monthly average.
Monthly global midpoint surface temperature anomalies from the JRA-55 reanalysis product, using its standard 1991-2020 baseline period. Lines show global surface temperature anomalies for each year since the record began in 1958, with years coloured by decade. The current year (2023) is shown in black. Chart by Stat Brief.
October is projected to not be quite as lattermost as September’s record-shattering anomaly, but will still come in as the second highest oddity of any month in 2023 to-date.
In wing to temperature anomalies, reanalysis products are worldly-wise to provide an well-judged near-real-time estimate of global wool temperatures. The icon unelevated shows the wool temperature of each month of 2023 compared to all prior years in the record, with Stat Brief’s October estimate and its uncertainties shown.
Monthly wool global stereotype surface temperatures from the JRA-55 reanalysis product. Lines show global surface temperatures for each year since the record began in 1958, with years coloured by decade. The current year (2023) is shown in black. Chart by Stat Brief.
Unpacking the drivers of recent record warmth
The lattermost surface temperatures seen over the past few months have triggered a broader debate in the scientific polity virtually its potential drivers.
For example, the world has never seen a month exceed the prior monthly record by 0.5C – as experienced in September. The closest terminology is February 2016, where global temperatures write-up the prior record by 0.47C.
However, February 2016 was shortly without the peak of a super El Niño event – when the effect of El Niño on global temperatures is expected to be the largest. September 2023, by contrast, occurred early in the incubation of the current El Niño event when the contribution to global temperatures is typically much smaller.
This has led to a search for volitional explanations of factors contributing to recent record warmth. While the rapid switch from modest La Niña conditions at the start of the year to growing El Niño conditions on top of human-driven warming remains the primary explanation, it cannot hands explain the full extent of lattermost global temperatures over the past few months.
A number of variegated potential contributors to recent global temperature records have been identified, including an uptick in the 11-year solar cycle, an unusual volcanic eruption last year that put a large value of water vapour into the stratosphere with minimal cooling sulphate aerosols, and a 2020 phaseout of planet-cooling sulphur dioxide in marine shipping fuels.
The icon below, ripened by Dr Robert Rohde at Berkeley Earth, shows a current best-estimate of the impact of each of these effects over the past 10 years based on published studies to-date. The shading indicates a warming (red) or cooling (blue) influence on global temperatures.
While each of these factors are small on their own, their combined effects may be to add virtually 0.1C to global temperatures in 2023.
Estimated drivers of global surface temperature incubation over the past decade. Note that marine fuel pollution reduction should technically be part of human-caused global warming (which includes both greenhouse gas and vaporizer emissions), but is separated out for clarity. Credit: Berkeley Earth
Temperatures are tracking climate model projections
Climate models provide physics-based estimates of future warming given variegated assumptions well-nigh future emissions, greenhouse gas concentrations and other climate-influencing factors.
The icon unelevated shows the range of individual models forecasts featured in the Intergovernmental Panel on Climate Change’s (IPCC) fifth towage report – known collectively as the CMIP5 models – between 1970 and 2030, with grey shading and the stereotype projection wideness all the models shown in black. Individual observational temperature records are represented by coloured lines.
In these models, estimates of temperatures prior to 2005 are a “hindcast” using known past climate influences, while temperatures projected without 2005 are a “forecast” based on an estimate of how things might change.
Twelve-month stereotype global stereotype surface temperatures from CMIP5 models and observations between 1970 and 2023. Models use RCP4.5 forcings without 2005. They include sea surface temperatures over oceans and surface air temperatures over land to match what is measured by observations. Anomalies plotted with respect to a 1981-2010 baseline. Chart by Stat Brief.
While global temperatures were running unelevated the pace of warming projected by climate models between 2005 and 2014, the past decade has been closer to the model average.
Currently the latter part of 2022 and early 2023 is suppressing the 12-month stereotype compared to the most recent months, but observations are expected to be well whilom the model stereotype by mid-2024.
Record upper ocean heat content
Human-emitted greenhouse gases trap uneaten heat in the atmosphere. While some of this warms the Earth’s surface, the vast majority – around 93% – goes into the oceans. Well-nigh two-thirds of this accumulates in the top 700 metres, but some moreover ends up in the deep oceans.
The icon unelevated shows yearly OHC estimates between 1950 and present for both the upper 700 metres (light undecorous shading) and 700-2000 metre (dark blue) depths of the ocean.
Monthly global ocean heat content (in zettajoules – billion trillion joules, or 10^21 joules) for the 0-700 metre and 700-2000 metre layers. Data from IAP. Chart by Stat Brief.
In many ways, OHC represents a much largest measure of climate transpiration than global stereotype surface temperatures. It is where most of the uneaten heat ends up and is much less variable on a year-to-year understructure than surface temperatures.
Just well-nigh every year since 1991 has set a new OHC record, showing that heat has unfurled to yaffle in the Earth system as concentrations of atmospheric greenhouse gases have increased.
Over the last 12 months, ocean heat content has increased by 42 zettajoules, or virtually 72 times as much as the total energy produced by all human activities on Earth last year.
Record low Antarctic sea ice extent
Highly well-judged observations of Arctic and Antarctic sea ice have been misogynist since polar-observing satellites became misogynist in the late 1970s.
The icon unelevated shows both Arctic (red) and Antarctic (blue) sea ice extent in 2023, the historical range in the record between 1979 and 2010 (shaded areas) and the record lows (dotted woebegone line).
Arctic and Antarctic daily sea ice extent from the US National Snow and Ice Data Center. The unvigilant lines show daily 2023 values, the shaded zone indicates the two standard deviation range in historical values between 1979 and 2010. The dotted woebegone lines show the record lows for each pole. Chart by Stat Brief.
Arctic sea ice extent during the first three quarters of 2023 has been at the low end of the historical 1979-2010 range, but has not seen any record daily lows except for a few days in February and April.
The yearly minimum sea ice extent in September was the sixth lowest on record, though still well whilom the record low set in 2012.
Weekly Arctic sea ice extent from the US National Snow and Ice Data Center. Chart by Stat Brief.
Antarctic sea ice, on the other hand, has set new all-time low records for most of 2023, set a new all-time low extent in February 2023, and has been far unelevated any prior levels overly since mid May.