The 2024 global average surface temperature was 1.55°C above the 1850-1900 average, according to WMO’s consolidated analysis of six datasets.
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Differences between datasets are mainly due to the ways temperatures are measured, e.g. ERA5 measures the temperature of the air above oceans, whereas NASA and NOAA measure the surface temperature of the water, which is lower. There can also be differences in how temperatures are measured in areas with sea ice - the sea ice can be measured, or the water underneath the sea ice, or the air above the sea ice. Also, in some areas there once was sea ice that has meanwhile disappeared. Different ways of measuring things can raise the temperature record by as much as 0.2°C and even more in case of earlier years, where the margin of error is also larger.
Importantly, the temperature rise in the above image is compared to the period 1850-1900, which is not pre-industrial. When using a genuinely pre-industrial base, the temperature anomaly may already have been above the 2°C threshold in 2015, when politicians at the Paris Agreement pledged that this threshold wouldn't be crossed.
“Individual years pushing past the 1.5 degree limit do not mean the long-term goal is shot", UN Secretary-General Antóno Guterres says: “It is important to emphasize that a single year of more than 1.5°C for a year does NOT mean that we have failed to meet Paris Agreement long-term temperature goals, which are measured over decades rather than an individual year", WMO Secretary-General Celeste Saulo adds.
However, for this argument to hold, the average anomaly would need to fall to under 1.5°C from now. Should we really have to wait for another decade or two, before a confirmation is allowed to be issued that 1.5°C has been crossed. Isn't such a mandate part of downplaying how dire the situation is, an effort to delay the necessary action? Moreover, does such a mandate make sense?
To illustrate this point, the above image uses NASA anomalies (blue dots) that are conservatively compared to NASA's default 1951-1980 base, with data going back to 2010. The image thus shows a 30-year review period centered around January 1, 2025. Eight imaginary years of data have been added beyond existing data, extending the trend into the future (yellow dots). The wide pink trend is based on both NASA existing data and these imaginary data, jointly covering data from 2010-2032. The narrow black trend is not based on imaginary data, it is purely based on existing data, from 2010-2024, showing the potential for such a trend to eventuate when using existing (i.e. past) data only.
In case such a trend would indeed eventuate, confirmation of the crossing of the 1.5°C threshold should NOT be delayed until all the years of a 30-year period have been entirely completed. In fact, 2°C (vs 1951-1980) would already be crossed early 2026. In the course of 2032, a 16°C rise would be reached, while the average anomaly for the period 2010-2032 would be higher than 3°C (vs 1951-1980) with still 7 years to go before the 30-year period would be completed.
Warnings about the potential for such a rise have been sounded before, e.g. see the extinction page.
See also the image below with daily data.
[ temperature anomaly with ENSO shading, trends added, from an earlier post ]
Human extinction at 3°C
If the temperature does indeed keep rising rapidly, the anomaly compared to pre-industrial may soon or already be higher than 3°C, implying that humans are already functionally extinct, especially if no decisive, comprehensive and effective action is taken.
Analysis by Shona and Bradshaw found that, due to co-extinction, global biodiversity collapse occurs at around 5°C heating, as discussed in a 2019 post with the warning that a rise of more than 5°C could happen within a decade, possibly by 2026, and that humans who depend on many other species will likely go extinct with a 3°C rise.
A recent study by Joseph Williamson et al. finds that many species that live together appear to share remarkably similar thermal limits. That is to say, individuals of different species can tolerate temperatures up to similar points. This is deeply concerning as it suggests that, as ecosystems warm due to climate change, species will disappear from an ecosystem at the same time rather than gradually, resulting in sudden biodiversity loss. It also means that ecosystems may exhibit few symptoms of heat stress before a threshold of warming is passed and catastrophic losses occur.
Arctic sea ice
[ Arctic sea ice extent, click on images to enlarge ]
During the first few months of the year, Arctic sea ice is still growing in extent. In the above image, the red line and red marker shows 2025 sea ice extent. Dots mark Arctic sea ice extent on January 19 for the respective year and Arctic sea ice extent was at a record low for the time of year on January 19, 2025, despite La Niña conditions.
A new El Niño may emerge in the course of 2025, while both Arctic sea ice extent and volume are at record low, while numerous self-reinforcing feedbacks are kicking in with accelerating ferocity and while further mechanisms are active that drive up temperatures such as high sunspots. Such a combination of mechanisms could cause a huge temperature rise and a Blue Ocean Event in 2025, threatening huge amounts of methane to erupt from the seafloor.
[ Arctic sea ice volume, click to enlarge ]
On Jan 18, 2025, the sea surface temperature south of Svalbard (green circle) was 5.1°C, 3.4°C higher than 1981-2011, as the above image shows.
High ocean temperatures result in low Arctic sea ice volume, as illustrated by the image on the right and discussed in this earlier post.
Guy McPherson discussed the consequences of an ice-free Arctic Ocean in the video below, adding that "a near-term, ice-free Arctic Ocean—the so-called Blue Ocean Event—is the extinction-causing event over which we have the least control. The rate of environmental change in the wake of such an event will suffice to cause the extinction of all life on Earth.
I’m not a fan."
Climate Emergency Declaration
The situation is dire and the precautionary principle calls for rapid, comprehensive and effective action to reduce the damage and to improve the situation, as described in this 2022 post, where needed in combination with a Climate Emergency Declaration, as discussed at this group.
Models that analyze what is driving up the temperature all too often omit specific sources, or when included, models all too often downplay their contribution. Accordingly, policies that are promoted based on such models are all too often ineffective or even counter-productive.
Methane is all too often referred to as 'natural gas' originating from wetlands, swamps, cows and pigs, as if calling methane 'natural' implied that human activities were not responsible for such emissions. Moreover, people with vested interests all too often suggest that such 'natural emissions' should be captured and used for heating, cooking or industrial purposes, to offset 'human emissions'. Similarly, forest fires are all too often referred to as 'wildfires', as if human activities were not responsible for them.
The compilation of images below shows forest fires as the largest source of carbon dioxide emissions on October 26, 2024. An image of carbon monoxide is also added (bottom right), as carbon monoxide is an indicator of forest fires. Carbon monoxide is also important since it is a precursor of tropospheric ozone and carbon monoxide depletes tropospheric hydroxyl radicals, thus extending methane's lifetime.
The methane image (top right) shows a high presence of methane in northern Europe. The cause for this is the high temperatures anomaly in northern Europe on October 26, 2024, resulting in strong decomposition of vegetation, which comes with high emissions of carbon dioxide, carbon monoxide and methane.
The high temperatures anomaly in northern Europe is illustrated by the above image. The image also illustrates polar amplification of the temperature rise, one of the mechanisms that drives up the temperature rise. Numerous mechanisms driving up the temperature rise are discussed in an earlier post that warns about a Double Blue Ocean Event. Thawing permafrost can cause huge emissions of carbon dioxide (CO₂), methane and nitrous oxide.
Many models go back only to 1750, many even use an earlier base, as if concentrations of greenhouse gases only started to rise then.
The image on the right shows IPCC and WMO values for the rise of methane (CH₄), carbon dioxide (CO₂) and nitrous oxide (N₂O) from 1750. The image shows that:
- Methane rose to 265% its 1750 value.
- Carbon dioxide rose to 151% its 1750 value. - Nitrous oxide rose to 125% its 1750 value.
Note that values for methane as low as 550 ppb and carbon dioxide as low as 260 ppm have been found in ice cores corresponding with periods thousands of years ago, as illustrated by the image below, from the pre-industrial page, based on Ruddiman et al. (2015).
According to the Met Office, climate sensitivity is typically defined as the global temperature rise following a doubling of CO₂ concentration in the atmosphere compared to pre-industrial levels. Pre-industrial CO₂ was about 260 parts per million (ppm), so a doubling would be at roughly 520 ppm.
A recent study found that doubling the atmospheric CO₂ levels could cause an increase in Earth’s average temperature of 7 to 14°C (13 to 25.2°F). In the video below, Guy McPherson discusses the study.
How fast could a rise to 520 ppm CO₂ unfold? Models typically put 520 ppm CO₂ far away in the future. The image below shows an analysis based on August 2009 through July 2024 data that has a trend added pointing at 520 ppm CO₂ getting crossed in 2029 and 1200 ppm CO₂ getting crossed in early 2035. In other words, the clouds tipping point could get crossed in early 2035 due to rising CO₂ alone, and because this tipping point is measured in CO₂e, this could occur well before 2035 when including the impact of feedbacks and further mechanisms.
Another way the danger of rising temperatures is all too often downplayed is to suggest that many feedbacks work only over very long timescales. This narrative may be convenient for politicians who rarely bother about what happens beyond the next election. However, as discussed in a recent post, there are many mechanisms that can push up the temperature rapidly, adding up to a potential rise of more than 18°C within years.
Climate Emergency Declaration
Instead of omitting them, all mechanisms driving up the temperature should be fully included in an action plan that seeks to improve the situation. Multiple policy instruments and combinations of policy instruments should be considered for implementation, preferably through local feebates.
The situation is dire and the precautionary principle calls for rapid, comprehensive and effective action to reduce the damage and to improve the situation, as described in this 2022 post, where needed in combination with a Climate Emergency Declaration, as discussed at this group.
The image below shows that the monthly Atlantic surface temperature anomaly in February 2024 was 1.176°C when compared to a 1951-1980 base.
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The image below shows that the monthly Atlantic surface temperature anomaly in February 2024 was 1.435°C when compared to a 1901-2000 base.
The difference illustrates the importance of selecting a base to calculate anomalies from. The anomaly indicates how much heat has accumulated in the Atlantic, and it is even larger for February 2024 when using a genuinely pre-industrial base, as discussed earlier.
The images also highlight the potential for the slowing down of the Atlantic meridional overturning circulation (AMOC) to contribute to more heat accumulating at the surface of the Atlantic Ocean.
As temperatures rise, many feedbacks are kicking in with greater ferocity, including increased stratification of oceans, loss of sea ice, loss of reflectivity of clouds and increased freshwater due to stronger melting of sea ice and glacial ice, due to heavier runoff from land and rivers and due to changes in ocean circulation.
While this may look to cause less ocean heat to reach the Arctic Ocean at the moment, the result is that a huge amount of ocean heat is accumulating in the North Atlantic that threatens to abruptly move into the Arctic Ocean. The danger is that an influx of ocean heat can cause large amounts of methane to erupt from the seafloor of the Arctic Ocean.
The inset on the top image illustrates that, as people's emissions raise the temperature, this rise can strengthen wind, evaporation, ocean currents and rainfall locally, resulting in greater potential for a lid to form and spread at the surface of the North Atlantic. As temperatures rise and winds strengthen, more evaporation can occur in one place and more rain can then fall further down the path of the Gulf Stream, i.e. an ocean current that extends into the Arctic Ocean, as part of AMOC. This rain further contributes to the freshwater accumulation at the surface of the North Atlantic.
In the video below, Guy McPherson discusses a recent study by Marilena Oltmanns et al. on some of these issues.
This page further discusses formation of a cool freshwater lid at the surface of the North Atlantic and the contribution to this of Jet Stream changes. The image below shows that the Jet Stream reached speeds as high as 455 km/h or 283 mph north of Washington on February 18, 2024 03:00 UTC, with Instantaneous Wind Power Density as high as 387.5 kW/m².
A huge amount of ocean heat is accumulating in the North Atlantic and threatens to abruptly move into the Arctic Ocean. The danger is that, due to strong wind along the path of the Gulf Stream, huge amounts of ocean heat will abruptly get pushed into the Arctic Ocean, with the influx of ocean heat causing destabilization of hydrates contained in sediments at the seafloor of the Arctic Ocean, resulting in eruptions of huge amounts of methane.
Strong hurricanes can significantly add to the danger. More hurricanes are forecast for the 2024 Atlantic hurricane season than during 1950-2020, as illustrated by the image below.
Many of the dangers have been discussed before, e.g. the danger that sea currents in the Arctic Ocean will change direction, in this 2017 post.
Arctic sea ice thickness warning
The compilation image below shows Arctic sea ice on March 28, 2024. The satellite image (left) may indicate extensive sea ice, but clouds can obscure things. The other image (right) indicates that sea ice in a large area from the Laptev Sea down to the North Pole may be very thin.
The image below illustrates the decline of Arctic sea ice volume over the years.
The images above and below show that Arctic sea ice volume has recently been the lowest on record for the time of year.
Given that Arctic sea ice currently is still relatively extensive, this low volume indicates that sea ice is indeed very thin, which must be caused by ocean heat melting sea ice from below, since little or no sunshine is yet reaching the Arctic at the moment and air temperatures are still far below freezing point, so where ocean heat may be melting sea ice away from below, a thin layer of ice will quickly be reestablished at the surface.
This situation looks set to dramatically change over the next few months, as air temperatures will rise and as more ocean heat will reach the Arctic Ocean. Moreover, as illustrated by the map below, much of the thicker sea ice is located off the east coast of Greenland. This sea ice and the purple-colored sea ice can be expected to melt away quickly with the upcoming rise in temperatures over the next few months.
Climate Emergency Declaration
The situation is dire and the precautionary principle calls for rapid, comprehensive and effective action to reduce the damage and to improve the situation, as described in this 2022 post, where needed in combination with a Climate Emergency Declaration, as discussed at this group.
The above image, adapted from NASA and the image below, adapted from Climate Reanalyzer and using the same baseline, illustrate the September 2023 temperature anomaly.
September 2023 was the month with the highest temperature anomaly on record. What contributed to this?
El Niño
The temperature rose about 0.5°C from November 2022 to March 2023, and this occurred at a time when we were not even in an El Niño yet, as illustrated by the above image, from an earlier post. Below is an updated image, from January 1950 to September 2023, adapted from NOAA
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The current El Niño is still strengthening, as illustrated by the image on the right, adapted from IRI.
Further contributors
There are further reasons why the temperature can be expected to keep rising beyond September 2023.
The number of sunspots has been higher than predicted and looks set to keep rising above predicted levels until July 2025, as discussed here.
The eruption of the submarine volcano near Tonga in January 2022 caused a lot of water vapor to reach high up into the atmosphere and this may still contribute to the temperature rise, as discussed here.
Aerosols that have a cooling effect, such as dust and sulfates (SO₄), are also important. As fossil fuel is burned, sulfates are co-emitted. Since they pollute the air, measures have been taken and are being taken to reduce them, e.g. in shipping, and this has pushed up the temperature rise. Meanwhile, cooling aerosols such as sulfates are still high. As illustrated by the image below, adapted from nullschool.net, SO₄ was as high as 8.621 τ at the green circle on October 6, 2023, at 07:00 UTC. In future, SO₄ could fall dramatically, e.g. in case of a sudden economic collapse, reducing the aerosol masking effect rapidly and abruptly causing a substantial rise in temperature.
After little change in the Antarctic sea ice extent graph for decades, extent loss was dramatic in 2022 and even more dramatic in 2023, as less and less sunlight was getting reflected back into space and instead was getting absorbed by the water of the Southern Ocean, as illustrated by the image below, adapted from NSIDC.
Sea ice retreat comes with loss of albedo, i.e. loss of the amount of sunlight reflected back into space, resulting in more heat getting absorbed in the Southern Ocean, making it a self-reinforcing feedback loop. Clouds constitute another self-reinforcing feedback loop; a warmer Southern Ocean comes with fewer bright clouds, further reducing albedo, as discussed here and here. For decades, there still were many lower clouds over the Southern Ocean, reflecting much sunlight back into space, but these lower clouds have been decreasing over time, further speeding up the amount of sunlight getting absorbed by the water of the Southern Ocean, and this 'pattern effect' could make a huge difference globally, as a recent study points out. Emissivity is a further factor; open oceans are less efficient than sea ice when it comes to emitting in the far-infrared region of the spectrum (feedback #23 on the feedbacks page).
The above image was created by Zach Labe with NSIDC data (Arctic + Antarctic) for each year from 1979 to 2023 (satellite-era; NSIDC, DMSP SSM/I-SSMIS). The image illustrates that global sea ice extent recently reached the largest anomaly in the satellite record. Anomalies are calculated using a 5-day running mean from a climatological baseline of 1981-2010. 2016 is shown with a yellow line. 2023 is shown using a red line (updated 10/16/2023).
In the video below, Paul Beckwith discusses the importance of loss of sea ice at around -60° (South).
As said, there are many factors behind the temperature increase around latitude -60° (South). As Paul mentions, this latitude receives a lot of sunlight around the year. Therefore, it is not surprising that, as oceans continue to heat up, there is huge loss of sea ice at this latitude, as well as loss of lower clouds, while open oceans are additionally less efficient than sea ice when it comes to emitting in the far-infrared region of the spectrum. The image below, adapted from NASA, shows a white band around -60° (South), indicating that the Southern Ocean has long been colder there than elsewhere, but has recently started to catch up with the global temperature rise.
The above image also illustrates that anomalies are highest in the Arctic, narrowing the temperature difference between the Arctic and the Tropics, with the air flow slowing down accordingly.
This in turn changes the Jet Stream and the Polar Vortex, resulting in blocking patterns that can, in combination with rising temperatures, strongly increase the frequency, intensity, duration and area coverage of extreme weather events such as storms and lightning, heatwaves and forest fires.
Forest fires in Canada have been releasing massive amounts of emissions that push up the temperature, including greenhouse gases such as carbon dioxide, warming aerosols such as black carbon & brown carbon and NMVOC (non-methane volatile organic carbon) and carbon monoxide that reduce the availability of hydroxyl, resulting in more methane and ozone in the atmosphere.
[ NH sea surface temperature anomaly ]
At the same time, slowing down of the Atlantic Meridional Ocean Current (AMOC) can result in more ocean heat accumulating at the surface of the North Atlantic, as illustrated by the image on the right, from an earlier post.
As temperatures rise, increased meltwater runoff from Greenland and more icebergs moving south, in combination with stronger ocean stratification and stronger storms over the North Atlantic, can also cause a freshwater lid to form at the surface of North Atlantic that can at times enable a lot of hot water to get pushed abruptly underneath this lid toward the Arctic Ocean. The danger is that more heat will reach the seafloor and destabilize methane hydrates contained in sediments at the seafloor of the Arctic ocean.
Ominously, very high methane levels continue to be recorded at Barrow, Alaska, as illustrated by the image below, adapted from NOAA.
The next few months will be critical as Arctic sea ice is sealing off the Arctic Ocean from the atmosphere, trapping heat underneath the ice and making it harder for ocean heat to get transferred from the Arctic Ocean to the atmosphere above the Arctic. Furthermore, sea ice is very thin, reducing the latent heat buffer that could otherwise have consumed ocean heat.
The next danger is that the thin Arctic sea ice will rapidly retreat early next year as a warming Arctic Ocean will transfer more heat to the atmosphere over the Arctic, resulting in more rain and more clouds in the atmosphere over the Arctic, speeding up sea ice loss and further pushing up the temperature rise over the Arctic, as discussed at the feedbacks page, which also discusses how less Arctic sea ice can push up temperatures through the emissivity feedback. As temperatures rise over the Arctic, permafrost on land also threatens to thaw faster, threatening to cause huge releases of greenhouse gases, including carbon dioxide, methane and nitrous oxide.
Meanwhile, emissions of greenhouse gases keep rising, further pushing up the temperature, as illustrated by the image below, from an earlier post.
[ Global energy-related greenhouse gas emissions 2000-2022, adapted from EIA ]
In the video below, Guy McPherson describes how temperature rise, loss of habitat and meltdown of nuclear power facilities each could result in rapid extinction of humans and many other species.
There are numerous further feedbacks that can accelerate the temperature rise and tipping points that can get crossed and cause even more abrupt rise of the temperature. One of these is the clouds tipping point that in itself can cause a temperature rise of 8°C, as discussed here.
Further feedbacks are also discussed at the Extinction page. One further feedback is water vapor. A warmer atmosphere holds more water vapor, at a rate of 7% for each Degree Celsius the temperature rises. As temperatures keep rising, ever more water vapor will be sucked up by the atmosphere. This will also cause more droughts, reducing the ability of land to sustain vegetation and provide soil cooling through shading and through evaporation and formation of lower clouds, as discussed here. More water vapor in the atmosphere will also speed up the temperature rise because water vapor is a potent greenhouse gas.
The fact that such tipping points and feedbacks occur as greenhouse gas levels reach certain levels and as the temperature rise makes it critical to assess how fast greenhouse gas levels could rise and by how much the temperature has already risen.
NASA data up through September 2023
The image below, adapted from NASA, shows that the September 2023 NASA Land+Ocean temperature was 1.78°C higher than it was in September 1923. The anomaly is 1.74°C when compared to a base centered around the year 1900 (1885-1915). The 1.74°C anomaly can be adjusted by 0.99°C to reflect a pre-industrial base, air temperature and higher polar anomalies (as shown in the box on the bottom right of the image), adding up to a potential anomaly of 2.73°C.
[ click on images to enlarge ]
Indeed, earlier analysis such as discussed here, points out that the temperature may already have risen by more than 2°C (compared to pre-industrial) in 2015, when politicians pledged at the Paris Agreement to take action to combat the temperature rise to prevent this from happening.
Blue: Polynomial trend based on Jan.1880-Sep.2023 data.
Magenta: Polynomial trend based on Jan.2010-Sep.2023 data.
The above image is created with NASA Land+Ocean monthly mean global temperature anomalies vs 1885-1915, adjusted by 0.99°C to reflect ocean air temperature, higher polar anomalies and a pre-industrial base, and has trends added.
Alarms bells have been sounding loud and clear for a long time, as discussed in posts such as this one, warning that the temperature could rise by more than 3°C by 2026. The above magenta graph shows how this could occur as early as next year (end 2024).
The above image illustrates the latent heat tipping point - estimated to correspond with a sea surface temperature anomaly of 1°C above the long term average (1901-1930 on the above image) - to get crossed and the seafloor methane tipping point - estimated to correspond with a sea surface temperature anomaly of 1.35°C - to get reached, as discussed in earlier posts such as this one, .
A Blue Ocean Event could occur as the latent heat and seafloor methane tipping points get crossed, and the ocean temperature keeps rising, as huge amounts of methane get released in the Arctic, as ever more heat keeps reaching and destabilizing methane hydrates contained in sediments at the seafloor of the Arctic Ocean, as discussed in many earlier posts such as this one.
Seafloor methane is one of many elements that could jointly cause a temperature rise of over 10°C, in the process causing the clouds tipping point to get crossed that can push up the temperature rise by a further 8°C, as illustrated by the image on the right, from the extinction page.
Conclusion
The precautionary principle should prevail and the looming dangers should prompt people into demanding comprehensive and effective action to reduce the damage and to improve the situation.