The first three quarters of 2023 has seen exceptional 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 around 0.5C.
In this latest “state of the climate” quarterly update, Carbon 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 exceptional 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 exceptionally far below 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 cool 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 figure below shows how global temperature so far in 2023 (black line) compares to each month in different 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 Carbon Brief.
Every month from June onward this year has set a clear record, with July, August and September shattering prior records by at least 0.3C (and around 0.5C in the case of September). The exceptional summer warmth means that it is now virtually certain that 2023 will be the warmest year on record.
In this latest quarterly state of the climate assessment, Carbon Brief analysed records from five different research groups that report global surface temperature records: NASA’s GISTEMP; NOAA’s GlobalTemp; Hadley/UEA’s HadCRUT5; Berkeley Earth; and Copernicus/ECMWF.
The figure below shows the annual temperatures from each of these groups since 1970, along with the average over the first nine months of 2023. (Note: at the time of writing, September data was not yet available for the Hadley/UEA record.)
Annual global mean surface temperatures from NASA GISTEMP, NOAA GlobalTemp, Hadley/UEA HadCRUT5, Berkeley Earth and Copernicus/ECMWF (lines), along with 2023 temperatures to date (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 Carbon Brief.
The globe as a whole has warmed around 1C since 1970, with strong agreement between different global temperature records. All show that year-to-date 2023 records are higher than any prior annual record. However, there are larger differences between temperature records further back 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 different 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 across all datasets.
However, from June onward each month has been unambiguously the warmest on record across all the different 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 across different datasets.
The continued strengthening of El Niño over the next few months means that it is likely that this streak of record-setting warmth will continue.
The figure below shows a range of different ENSO forecast models produced by different scientific groups. The values shown are sea surface temperature variations in the tropical Pacific – the El Niño 3.4 region – for three-month periods.
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 contributed to record heatwaves in many regions over the recent northern-hemisphere summer. The figure below shows the parts of the world that saw record warm or cold 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 area on Earth saw record cold (or even the second-to-fifth coldest temperatures on record).
In September alone, 77 different countries – mostly in Europe and the tropics – set new monthly average 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 characteristic “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.
October continuing the record warm streak
While global temperature records are not yet in for the full month of October 2023, real-time reanalysis products increasingly allow scientists to track global temperatures on a daily basis.
Reanalysis pulls together a huge amount of data from satellites, weather balloons, aeroplanes, weather stations, ships and buoys to provide a detailed look at how the Earth’s climate is changing in real-time.
Modern reanalysis products, such as JRA-55 and ERA5, use state-of-the-art methods to produce records that align well with traditional surface temperature datasets over recent decades.
In the figure below, Carbon Brief shows the daily global temperature anomaly values from the JRA-55 reanalysis product for each day since the record began in 1958 (grey lines). It shows the current year to date (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 further into the past.
The heat map below focuses on 2023, showing each day in the year, with columns representing each month. The red shading shows the temperature anomaly of each day, with darker shading indicating more extreme temperatures. The map highlights how extreme the prior four months (from July onward) have been compared to the prior period.
With most of the data for the month of October now available in the JRA-55 reanalysis product, Carbon 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 figure below shows Carbon Brief’s estimate for October, with uncertainty intervals estimates based on the historical relationship between the first 19 days of the month available at the time of publication and the overall monthly average.
October is projected to not be quite as extreme as September’s record-shattering anomaly, but will still come in as the second highest anomaly of any month in 2023 to-date.
In addition to temperature anomalies, reanalysis products are able to provide an accurate near-real-time estimate of global absolute temperatures. The figure below shows the absolute temperature of each month of 2023 compared to all prior years in the record, with Carbon Brief’s October estimate and its uncertainties shown.
Unpacking the drivers of recent record warmth
The extreme surface temperatures seen over the past few months have triggered a broader debate in the scientific community around 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 analogue is February 2016, where global temperatures beat the prior record by 0.47C.
However, February 2016 was shortly after 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 evolution of the current El Niño event when the contribution to global temperatures is typically much smaller.
This has led to a search for alternative 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 easily explain the full extent of extreme global temperatures over the past few months.
A number of different 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 amount 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 figure below, developed 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 around 0.1C to global temperatures in 2023.
Temperatures are tracking climate model projections
Climate models provide physics-based estimates of future warming given different assumptions about future emissions, greenhouse gas concentrations and other climate-influencing factors.
The figure below shows the range of individual models forecasts featured in the Intergovernmental Panel on Climate Change’s (IPCC) fifth assessment report – known collectively as the CMIP5 models – between 1970 and 2030, with grey shading and the average projection across 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 after 2005 are a “forecast” based on an estimate of how things might change.
Twelve-month average global average surface temperatures from CMIP5 models and observations between 1970 and 2023. Models use RCP4.5 forcings after 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 Carbon Brief.
While global temperatures were running below 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 average compared to the most recent months, but observations are expected to be well above the model average by mid-2024.
Record high ocean heat content
Human-emitted greenhouse gases trap extra heat in the atmosphere. While some of this warms the Earth’s surface, the vast majority – around 93% – goes into the oceans. About two-thirds of this accumulates in the top 700 metres, but some also ends up in the deep oceans.
The figure below shows annual OHC estimates between 1950 and present for both the upper 700 metres (light blue 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 Carbon Brief.
In many ways, OHC represents a much better measure of climate change than global average surface temperatures. It is where most of the extra heat ends up and is much less variable on a year-to-year basis than surface temperatures.
Just about every year since 1991 has set a new OHC record, showing that heat has continued to accumulate 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 around 72 times as much as the total energy produced by all human activities on Earth last year.
Record low Antarctic sea ice extent
Highly accurate observations of Arctic and Antarctic sea ice have been available since polar-observing satellites became available in the late 1970s.
The figure below 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 black line).
Arctic and Antarctic daily sea ice extent from the US National Snow and Ice Data Center. The bold lines show daily 2023 values, the shaded area indicates the two standard deviation range in historical values between 1979 and 2010. The dotted black lines show the record lows for each pole. Chart by Carbon 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 annual minimum sea ice extent in September was the sixth lowest on record, though still well above the record low set in 2012.
Weekly Arctic sea ice extent from the US National Snow and Ice Data Center. Chart by Carbon 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 below any prior levels ever since mid May.
Weekly Antarctic sea ice extent from the US National Snow and Ice Data Center. Chart by Carbon Brief.
The post State of the climate: Global temperatures throughout mid-2023 shatter records appeared first on Carbon Brief.
State of the climate: Global temperatures throughout mid-2023 shatter records
Claver Gatete is Executive Secretary of the UN Economic Commission for Africa. Jason Veysey is Energy Modeling Program Director and Senior Scientist at the Stockholm Environment Institute. Lisa Sachs is Director of the Columbia Center on Sustainable Investment at Columbia University.
The case for global energy transition has rarely been clearer. The closure of the Strait of Hormuz earlier this year exposed the cost of unplanned, fossil-dependent systems, while the falling cost of renewables, the rising penetration of electric vehicles, and the growing value of demand flexibility have made the direction of travel obvious. The benefits of a clean, secure, integrated system are no longer in dispute. What remains unclear is how to build it.
Countries around the world have called for faster renewable energy deployment and alternative energy arrangements. A secure, affordable, resilient, decarbonised system requires specific investments in specific places in a specific sequence, optimised across sectors and borders. But very few governments have the analytical foundation to translate those imperatives into investment.
The two instruments that are supposed to determine investment priorities for decarbonisation – Nationally Determined Contributions (NDCs) and country platforms – cannot answer the most basic question facing any country undertaking an energy transition: what should the energy system look like?
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To close this gap, every country needs a bankable, economy-wide optimisation model for its energy system. A model is not a plan, but it can help answer the critical question of what the future energy system should look like. It shows how optimal scenarios vary as assumptions and policies are adjusted, calculates investment requirements and sequencing, and quantifies how system costs are affected by assumptions, policies, and exogenous variables like trade policy and financing terms.
Tool for efficient investment
Optimisation is a simplified way of simulating an energy system, but it can be an extremely powerful tool for moving energy planning from reactive (how do we manage the disparate actions in the energy system?) to intentional (what energy system underpins our national objectives?). A model can show how optimal scenarios vary as assumptions and policies are adjusted, and how investment requirements are quantified and sequenced.
Optimisation models can treat the energy system and the sectors it serves as an integrated whole, optimising across sectors and projects in ways that can be mutually reinforcing. If considered independently, growth in industrial demand, transport electrification, and digital infrastructure can add stress to the energy system. But an optimised plan can arrange these and other changes in an efficient, synergistic way.
Two to tango: How governments can unlock private investment for national climate goals
New load can be added where low-cost power is available; industrial customers can ensure the viability of investments in energy supply; electric vehicle charging policy can smooth load curves and reduce costs for all consumers.
Additionally, optimisation modeling can also change the financeability of investments. Taken alone, each project faces uncertainty about the rest of the system, which raises the cost of capital and causes projects to stall or unwind after contracts are signed. A coherent, optimised plan makes visible the coordination that private capital would otherwise have to bet on: identified offtake, sequenced and committed transmission, contracted power supply, and so on.
What COP31 and COP32 should do
The upcoming COPs in Turkey and Ethiopia can shift the center of gravity of international climate cooperation from fragmented commitments to planning. Three moves are urgently needed.
First, optimised, economy-wide, long-term energy system planning must be the foundation on which any meaningful NDC, country platform, or finance commitment rests. NDCs are typically drafted by environment or single-line ministries, with limited cross-sectoral input from ministries of energy, finance, and planning. They contain targets, derived from sectoral strategies or national commitments, not from an analytically grounded picture of what the energy system should look like and what investments would make it work. Country platforms are generally a portfolio of investments assembled from existing project pipelines, rather than derived from a system-level analysis of what an optimised, decarbonised energy system would require.
Second, recognise regions as a key planning unit. Modern integrated energy systems are inherently regional. Renewable endowments are unevenly distributed; balancing variable supply across borders lowers aggregate cost, reduces redundant backup capacity, and unlocks economies of scale no individual nation can achieve. Many energy investments in Southeast Asia, East Africa, Southern Africa and Central Asia may only be financeable in a regional context. Assessing domestic infrastructure without regional optimisation perpetuates the perception that decarbonisation is more expensive than it is.
COP31 leaders unveil global targets, with spotlight on electrification
Third, finance the planning capacity. A coordinated commitment by multilateral development banks, bilateral donors, and philanthropic partners to help every region and its constituent countries develop and maintain their own modelling capability, with open-source tools and regional analytical hubs, would close the most consequential gap in the current architecture. The cost is small relative to current spending on country platforms, failed project preparation, and misallocated infrastructure investment.
This includes supporting regional institutions such as the ASEAN Centre for Energy, the African Energy Commission, regional power pools, and the Latin American and Caribbean Energy Organization to determine what optimised regional systems require. Country-by-country pledging, repeated at every COP, will not deliver what meaningfully integrated systems can.
The 2026 energy crisis made the cost of unplanned, fossil-dependent systems newly visible. That window of clarity will close. The international community should seize the moment to build the planning foundation that has been missing for thirty years, rather than commissioning another round of NDCs or pledges, striving for outcomes neither was designed to deliver.
The post Every country needs a model to help optimise its energy transition appeared first on Climate Home News.
Every country needs a model to help optimise its energy transition
The world is currently experiencing what is expected to become the strongest El Niño on record – dubbed a “super El Niño” by many.
El Niño is the warm phase of a recurring climate pattern in the tropical Pacific that releases heat from the ocean into the atmosphere.
This temporarily raises global temperatures and reshapes rainfall and extreme weather around the world – impacting the lives of billions of people.
The current El Niño event began in June and is expected to last into 2027.
El Niño is part of a wider climate pattern called the El Niño-Southern Oscillation (ENSO) cycle.
The ENSO cycle also has a cool phase, known as La Niña, as well as a “neutral” phase. El Niño and La Niña events typically last between nine and 12 months, but can go on longer.
Below, Carbon Brief explains how the ENSO cycle works, its impacts on extreme weather and global temperatures and why this El Niño event is projected to be the most intense since records began.
The post Explainer: How the ‘super El Niño’ will reshape the world’s weather appeared first on Carbon Brief.
https://interactive.carbonbrief.org/el-nino-explainer/index.html
The second-largest reservoir in the US reached a record-low water height on Saturday – just days after the country’s largest reservoir broke its own record.
Both Lake Mead and Lake Powell are located on the Colorado River.
They provide water for populations across seven US states in the south-western US, with around 40 million people getting some or all of their municipal water from the Colorado River.
The river also provides water for around 5.5m acres (22,258 square kilometres) of farmland across Colorado, Arizona, California and the other states in the river basin.
Experts tell Carbon Brief that climate change, population growth and over-consumption are all contributing to the current record-low levels of the reservoirs.
Record lows
At full capacity, Lakes Mead and Powell can hold a combined 68 cubic kilometres of water – enough to supply all household consumption in the contiguous US for nearly 1.5 years. However, the water level in both reservoirs has been declining for decades.
The chart below shows the water level of Lake Mead, in metres above mean sea level. The reservoir, which began to fill in 1935 following the construction of the Hoover Dam, has a “full pool” maximum capacity of 347.60 metres. The water level in Lake Mead reached a record low of 317.11 metres on 7 August.
The following chart shows the water level of Lake Powell, in metres above mean sea level. Lake Powell’s full-pool level is 1,127.76 metres.
While the reservoir reached its maximum capacity several times in the 1980s, it has not done so since. On 15 August, the water level in Lake Powell was recorded at a new record-low of 1,072.87 metres.
Both reservoirs have continued to decline in the days since breaking their respective records. The downward trend will largely continue in both lakes until next spring, when the snowpack in the mountains of the Upper Colorado River Basin begins to melt, says Dr Jack Schmidt, a senior research scientist at Utah State University’s Center for Colorado River Studies. He tells Carbon Brief:
“The big dilemma of the moment is that we’re only in the middle of August, and we have no assurance of what the coming winter will be. The only thing we can be sure of is that we will be depleting overall total basin reservoir storage from now until, roughly, early April.”
Compounding factors
The record lows across the two reservoirs are the result of several compounding factors, experts tell Carbon Brief.
Since the turn of the 20th century, the amount of water flowing along the Upper Colorado River has declined by about 20%. Research suggests that half of this decline can be attributed to human-induced climate change.
Most of the river’s streamflow comes from the snowpack of the Upper Colorado River Basin, which stretches across five western US states but is primarily located in Colorado and Utah.
This region has been gripped by a historic “megadrought” for more than a quarter of a century. Nearly half of the megadrought’s intensity over 2000-18 is attributable to climate change, according to a 2020 study.
At the same time, the increasing population in the US south-west has put added pressure on the Colorado River’s water supply. The number of people obtaining some or all of their water from the Colorado system has grown by 15 million (around 60%) since 1992.
Schmidt tells Carbon Brief:
“There’s an ultimate cause of the present water crisis, and there’s a proximate cause. The ultimate cause is a warming climate, a warming planet and a pretty clear correlation between warming conditions and decreased runoff in the Colorado River Basin.
“The proximate cause is that in this messy democratic republic of ours, big policy decisions that match the variability of the climate occur painfully slowly – with intense political negotiations – and only incrementally.”
On 31 July, the US Bureau of Reclamation, which manages water resources in the western US, released an environmental impact statement on its proposed post-2026 strategy for managing Lakes Powell and Mead. The strategy itself has not been released yet.
Schmidt notes that the statement does appear to give the Bureau flexibility to “respond to crisis” by reducing the delivery of water to several states. However, he adds:
“They acknowledge it won’t work if we just stay critically dry, and of course every climate model for the 21st century, especially with a continually warming planet, says that that’s exactly what’s going to happen.”
The post Analysis: The two largest reservoirs in the US have hit record-low levels appeared first on Carbon Brief.
Analysis: The two largest reservoirs in the US have hit record-low levels
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