Global Average Temperature 2024

[bluewave]

A new study on reduced shipping aerosols potentially contributing to the global temperature rise over the last year or so. 

https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2024GL109077

5 Synthesis and Conclusions

New methods are making rapid progress in identifying ship tracks with machine learning, and using trajectory methods and satellite imagery to understand the evolution of cloud properties over time for both visible and invisible tracks. These methods indicate significant reductions in visible ship tracks since the IMO2020 shipping regulations changes reduced sulfur emissions from ships. Global estimates are 25%–50% reduction in the number of visible tracks. This work should help us better constrain at the process level the impact of visible and “invisible” ship emissions on marine clouds and extend that globally.

Simulations with hybrid approaches and global models indicate a radiative forcing change of +0.12 ± 0.03 Wm⁻² could result from the reductions in sulfur emissions. This result is based on simulations from several models. However, further refinement of models is still desired. For example, simulations reduce shipping sulfur mass emissions, but the IMO2020 sulfur regulation has had a drastic effect on the size distribution and number of primary aerosols from shipping (Yu et al., 2020), affecting aerosol number and possibly radiative forcing.

There has been speculation that the record warm temperatures in 2023 are at least partially attributable to the reduction of cooling as a result of the IMO2020 regulations. The analysis of recent temperatures shows that the anomalies in temperature in 2022 and 2023 were correlated (in space) with changes in clouds. Since 2020 the correlation between temperature and clouds has been above 0.4, higher than over any 3 year period in the CERES record back to 2002. The magnitude of the observed cloud changes is too large to only be a cloud feedback response to temperature changes, implying that other factors have been modifying clouds. Further simulations analyzing cloud anomalies with and without surface temperature anomalies could be used to try to quantify the feedback contribution. Furthermore, there are significant (but weak) pattern correlations with simulations of cloud changes due to shipping emissions. The magnitude of the observed CRE anomalies is about 3X larger than would be expected from shipping emissions alone. On a global or Northern Hemisphere average, the CERES observed CRE is not anomalous over the 2020–2023 record, so no large scale shift in clouds is evident due to meteorology.

This analysis indicates it is plausible that the IMO2020 shipping regulations changes through sulfur emission reduction have significantly contributed to recent Northern Hemisphere temperature anomalies. Shipping cannot account for all of the observed warming. The analysis is done using 2 years of data data under the new shipping emissions, and only one set of model simulations is used for pattern correlations. However, the results are not that sensitive to the exact surface temperature data or dates used for the correlations, and the forcing is similar across models, and not dependent on the specific nudging period. Pattern correlations are significant but weak, and more detailed process analysis is needed.

Attribution with an energy balance model indicates that the global average contribution of shipping changes could be nearly 20% of expected warming by 2023. Energy balance modeling also indicates that perhaps half the total global warming of ∼0.07 K from the shipping emissions effects of +0.12 W m⁻² has been realized after four years (2020–2024), and continued warming is expected. The forcing is however highly localized. Based on the patterns of warming, a substantial part of 2023 warming over the N. Hemisphere mid-latitude oceans could be attributed to shipping emissions reductions. To constrain the attribution, further simulations with constrained coupled model simulations with an interactive ocean would likely be needed. However, this will not be trivial: the global shipping perturbation of +0.1 Wm⁻² and about 0.07 K of temperature rise would have to be discerned from coupled simulations with climate noise. As an example, the interannual standard deviation of 101 years (years 1100–1200) of the CESM2 pre-industrial control simulation (Danabasoglu et al., 2020) is 0.47 Wm⁻² for net TOA flux and 0.09 K for SST. Thus large ensembles, long runs and/or careful constraints would be required.

The IMO2020 regulations are a critical “natural laboratory” to determine whether continued declines in general air pollution due to regulations around the world will continue to increase and possibly accelerate global warming over the next decades (Hansen et al., 2023). This is critical for reducing the large uncertainty in climate forcing due to aerosols (Bellouin et al., 2020), and for evaluating the potential of intentional modification of marine clouds to offset global warming (Diamond et al., 2022).

To better constrain these results further at the process level, we need better access to ship position and type information from the Automatic Identification System (AIS), which broadcasts ship position and identification information. Almost all the AIS data (especially satellite derived open ocean data), even historical, is only available at a prohibitive cost. Releasing such data for research would allow detailed identification of specific ships with tracks, enabling extension of work by Gryspeerdt, Goren, et al. (2019) and Manshausen et al. (2022, 2023) to be conducted statistically and globally. This would enable us to directly link emissions to cloud perturbations and better constrain how much the IMO2020 regulations, and air pollution control in general, will contribute to global warming over the next decade.

The IMO2020 regulations can be seen as an inadvertent experiment in solar geo-engineering, but in reverse (warming). Ship sulfur reductions may have contributed a significant amount to the 2023 extreme temperatures in the Northern Hemisphere, but the estimated magnitude appears to be too small to be the only cause. The significant ENSO warm event in late 2023 would have played a role as well. Understanding and attributing the changes is not just relevant for ships and the current decade, but for several decades to come as the world rapidly decarbonizes and reduces all anthropogenic emissions of sulfur and other particulates. To what extent are we accelerating climate change by cleaning up air quality faster than limiting greenhouse gas emissions? Our inability to provide a robust attribution of global radiative forcing and resulting temperature changes even 3 years after such a large experiment speaks to the huge challenges in managing any deliberate intervention (Diamond et al., 2022) due to natural variability.

 

 

[chubbs]

Temperatures this year have been slow to fall, which almost guarantees another record. Year-to-date, ERA is running 0.24C warmer than 2023, and 0.22C warmer than 2016. The remainder of 2024 would have to average 0.41C on ERA to avoid a record, i.e. close to 2016. The rest of the year will be cooler than 2023, but not that cool. In a more likely scenario, 2024 continues to run 0.22C warmer that 2016, and breaks the record by 0.05C.

[Typhoon Tip]

On 8/15/2024 at 6:32 AM, bluewave said:

A new study on reduced shipping aerosols potentially contributing to the global temperature rise over the last year or so. 

https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2024GL109077

5 Synthesis and Conclusions

New methods are making rapid progress in identifying ship tracks with machine learning, and using trajectory methods and satellite imagery to understand the evolution of cloud properties over time for both visible and invisible tracks. These methods indicate significant reductions in visible ship tracks since the IMO2020 shipping regulations changes reduced sulfur emissions from ships. Global estimates are 25%–50% reduction in the number of visible tracks. This work should help us better constrain at the process level the impact of visible and “invisible” ship emissions on marine clouds and extend that globally.

Simulations with hybrid approaches and global models indicate a radiative forcing change of +0.12 ± 0.03 Wm⁻² could result from the reductions in sulfur emissions. This result is based on simulations from several models. However, further refinement of models is still desired. For example, simulations reduce shipping sulfur mass emissions, but the IMO2020 sulfur regulation has had a drastic effect on the size distribution and number of primary aerosols from shipping (Yu et al., 2020), affecting aerosol number and possibly radiative forcing.

There has been speculation that the record warm temperatures in 2023 are at least partially attributable to the reduction of cooling as a result of the IMO2020 regulations. The analysis of recent temperatures shows that the anomalies in temperature in 2022 and 2023 were correlated (in space) with changes in clouds. Since 2020 the correlation between temperature and clouds has been above 0.4, higher than over any 3 year period in the CERES record back to 2002. The magnitude of the observed cloud changes is too large to only be a cloud feedback response to temperature changes, implying that other factors have been modifying clouds. Further simulations analyzing cloud anomalies with and without surface temperature anomalies could be used to try to quantify the feedback contribution. Furthermore, there are significant (but weak) pattern correlations with simulations of cloud changes due to shipping emissions. The magnitude of the observed CRE anomalies is about 3X larger than would be expected from shipping emissions alone. On a global or Northern Hemisphere average, the CERES observed CRE is not anomalous over the 2020–2023 record, so no large scale shift in clouds is evident due to meteorology.

This analysis indicates it is plausible that the IMO2020 shipping regulations changes through sulfur emission reduction have significantly contributed to recent Northern Hemisphere temperature anomalies. Shipping cannot account for all of the observed warming. The analysis is done using 2 years of data data under the new shipping emissions, and only one set of model simulations is used for pattern correlations. However, the results are not that sensitive to the exact surface temperature data or dates used for the correlations, and the forcing is similar across models, and not dependent on the specific nudging period. Pattern correlations are significant but weak, and more detailed process analysis is needed.

Attribution with an energy balance model indicates that the global average contribution of shipping changes could be nearly 20% of expected warming by 2023. Energy balance modeling also indicates that perhaps half the total global warming of ∼0.07 K from the shipping emissions effects of +0.12 W m⁻² has been realized after four years (2020–2024), and continued warming is expected. The forcing is however highly localized. Based on the patterns of warming, a substantial part of 2023 warming over the N. Hemisphere mid-latitude oceans could be attributed to shipping emissions reductions. To constrain the attribution, further simulations with constrained coupled model simulations with an interactive ocean would likely be needed. However, this will not be trivial: the global shipping perturbation of +0.1 Wm⁻² and about 0.07 K of temperature rise would have to be discerned from coupled simulations with climate noise. As an example, the interannual standard deviation of 101 years (years 1100–1200) of the CESM2 pre-industrial control simulation (Danabasoglu et al., 2020) is 0.47 Wm⁻² for net TOA flux and 0.09 K for SST. Thus large ensembles, long runs and/or careful constraints would be required.

The IMO2020 regulations are a critical “natural laboratory” to determine whether continued declines in general air pollution due to regulations around the world will continue to increase and possibly accelerate global warming over the next decades (Hansen et al., 2023). This is critical for reducing the large uncertainty in climate forcing due to aerosols (Bellouin et al., 2020), and for evaluating the potential of intentional modification of marine clouds to offset global warming (Diamond et al., 2022).

To better constrain these results further at the process level, we need better access to ship position and type information from the Automatic Identification System (AIS), which broadcasts ship position and identification information. Almost all the AIS data (especially satellite derived open ocean data), even historical, is only available at a prohibitive cost. Releasing such data for research would allow detailed identification of specific ships with tracks, enabling extension of work by Gryspeerdt, Goren, et al. (2019) and Manshausen et al. (2022, 2023) to be conducted statistically and globally. This would enable us to directly link emissions to cloud perturbations and better constrain how much the IMO2020 regulations, and air pollution control in general, will contribute to global warming over the next decade.

The IMO2020 regulations can be seen as an inadvertent experiment in solar geo-engineering, but in reverse (warming). Ship sulfur reductions may have contributed a significant amount to the 2023 extreme temperatures in the Northern Hemisphere, but the estimated magnitude appears to be too small to be the only cause. The significant ENSO warm event in late 2023 would have played a role as well. Understanding and attributing the changes is not just relevant for ships and the current decade, but for several decades to come as the world rapidly decarbonizes and reduces all anthropogenic emissions of sulfur and other particulates. To what extent are we accelerating climate change by cleaning up air quality faster than limiting greenhouse gas emissions? Our inability to provide a robust attribution of global radiative forcing and resulting temperature changes even 3 years after such a large experiment speaks to the huge challenges in managing any deliberate intervention (Diamond et al., 2022) due to natural variability.

 

 

i've lamented at length ( no kidding! ) about a similar concern over the ancient pages of the thoughts on climate change thread ...

this aerosol modulation [possibly .. but who are we kidding - ] directly contributing to a reduction in cloud materialization -->  d(E budget ) has, to me, unwittingly provided a very good experimental opportunity.   the results of which proves my point.  and by extension, argues for why as a terraforming-capable species we need to be very careful in how it is we back away from the erstwhile forcing our activity has and continues to contribute.  

think alcoholic entering detox:   the last thing the medical staff would ever do to a hopelessly addicted, liver cirrhotic, physiologically chemical dependent patient is abruptly cut off the patient's access to alcohol.   

the patient is obviously the metaphor here; not to be taken in the literal sense. the point being, there are background processes that unless all are known, we're flying blind into a vast realm of cause-and-effects that can if not likely will lead to abrupt, unwanted responses. 

some of these are non-linear, too.   synergistic heat waves that over perform over leading guidance indicators, and the predictive assessments of humans that observe those indicators, is just one example of non-linear feed-backs causing a bigger response than anticipated.  but longer terms ... life itself, in the seas and land, and how et al have been adapting ( or struggling to; some are not making it!) may not be able to 'turn off' their offsetting defenses to climate change.  taking the world back to pre-industry too abruptly could have dire consequences.   yet, that antiquated state of affairs, where human activity wasn't nearly so capable of playing blind god with the world, appears now to be an imperative.  our father, who art in heaven ... bestowith upon us the rights to access the power of the cosmos.

i'll tell you, from my op ed position ( a little rhetorical fun here...) when humanity sold its soul to technology 250 years ago, we unwittingly also slaved our dependency to technology as our savior - salvation from the results of technology.  now that's an interesting predicament ... hints at a Fermi Paradox explanation ( for those privy to that stuff).  as in, too few alien worlds got past this 'discovery of dad's gun' stage of their own evolution.

in the contest of earth's greatest destructive forces to have ever afflicted, human innovation may turn out to be the prohibitive favorite.   maybe the greatest enemy of evolution turns out to be evolution itself.

[bluewave]

 

 

[bdgwx]

August 2024 beat August 2023 in the UAH dataset.

Here are the trends over periods of interest...

1st half: +0.14 C.decade-1
2nd half: +0.23 C.decade-1

Last 10 years: +0.39 C.decade-1
Last 15 years: +0.37 C.decade-1
Last 20 years: +0.30 C.decade-1
Last 25 years: +0.22 C.decade-1
Last 30 years: +0.18 C.decade-1

The warming rate acceleration is now +0.028 C.decade-2.

[chubbs]

19 hours ago, bdgwx said:

August 2024 beat August 2023 in the UAH dataset.

Here are the trends over periods of interest...

1st half: +0.14 C.decade-1
2nd half: +0.23 C.decade-1

Last 10 years: +0.39 C.decade-1
Last 15 years: +0.37 C.decade-1
Last 20 years: +0.30 C.decade-1
Last 25 years: +0.22 C.decade-1
Last 30 years: +0.18 C.decade-1

The warming rate acceleration is now +0.028 C.decade-2.

This nino has produced August UAH6 anomalies, this year and last, that are much higher than the previous high of 0.38 in August 1998 and even higher relative to recent Augusts. With the notable exception of 1998, enso effects on UAH6 have generally been weak in August and other summer month; but, this nino has maintained high UAH6 values through 2 summers. The $64 question is where will be next August, when nino effects are completely washed out.

 

[TheClimateChanger]

On 9/2/2024 at 12:20 PM, bdgwx said:

August 2024 beat August 2023 in the UAH dataset.

Here are the trends over periods of interest...

1st half: +0.14 C.decade-1
2nd half: +0.23 C.decade-1

Last 10 years: +0.39 C.decade-1
Last 15 years: +0.37 C.decade-1
Last 20 years: +0.30 C.decade-1
Last 25 years: +0.22 C.decade-1
Last 30 years: +0.18 C.decade-1

The warming rate acceleration is now +0.028 C.decade-2.

So surreal to see the "warmest decade of all time" [the 1990s - which many of y'all on Wright Weather and later on EasternUsWx.com incorrectly suggested was a "warm cycle" but which I, as a young child, I might add, correctly indicated would be the coldest decade of the rest of your lives] - now appear as frigid cold. I mean it looks colder than the 1800s looked back in the 1990s. Unreal.

 

[TheClimateChanger]

3 minutes ago, TheClimateChanger said:

So surreal to see the "warmest decade of all time" [the 1990s - which many of y'all on Wright Weather and later on EasternUsWx.com incorrectly suggested was a "warm cycle" but which I, as a young child, I might add, correctly indicated would be the coldest decade of the rest of your lives] - now appear as frigid cold. I mean it looks colder than the 1800s looked back in the 1990s. Unreal.

 

For the youngsters today, don't let Dr. Spencer gaslight you into believing the 1990s were unusually cold. The 1990s were the hottest decade of all time at that point in history. Even Dr. Spencer used to argue it was part of some cylical warming trend. He is the most wrong "scientist" of all time.

This is how the 1990s used to be displayed when I was growing up:

Source: The 1990s was the warmest decade ever recorded instrumentally. The last... | Download Scientific Diagram (researchgate.net)

[TheClimateChanger]

If you look carefully at the above graphic, you will notice more warming has occurred from the 1990s to today than had occurred from the 1860s to 2000 [or at least a similar degree of warming].

[bdgwx]

I have a few reasons to be critical of Dr. Spencer, but to be fair to him he posted this on his blog today. I'm more concerned with the likes of Joe Bastardi and Ryan Maue. 

I’m even part of the supposed 97% that believes the climate system is warming partly (maybe even mostly) from our CO2 emissions.

[chubbs]

21 hours ago, TheClimateChanger said:

If you look carefully at the above graphic, you will notice more warming has occurred from the 1990s to today than had occurred from the 1860s to 2000 [or at least a similar degree of warming].

2023, 2010 and 1973 below, we've come a long way just in the past 10-15 years.

[Typhoon Tip]

https://phys.org/news/2024-09-south-korea-highest-average-summer.html

[bdgwx]

Svalbard went crazy. I don't typically highlight individual locations like this, but since it is in the Arctic where it can at least somewhat represent the melting tendency on the sea ice I thought it might be interesting enough.

 

[Typhoon Tip]

2 hours ago, bdgwx said:

Svalbard went crazy. I don't typically highlight individual locations like this, but since it is in the Arctic where it can at least somewhat represent the melting tendency on the sea ice I thought it might be interesting enough.

 

i'll give the guy credit. that's a humorous delivery there -   

[Typhoon Tip]

what's perhaps most daunting of all about that svalbard location is that it's not like a freak low pulled a warm plume ... we're talkin' about a whole month average. 

[bluewave]

He wrote a great article about this extreme event.

https://www.daanvandenbroek.com/svalbards-3rd-consecutive-warmest-summer-on-record-august-shattering-multiple-records/

Southerly winds

Besides global warming and its impacts (diminishing sea ice, warming oceans and atmosphere, etc.), the extremely warm Augst was caused by anomalously persistent southerly winds, advecting extremely mild air from lower latitudes to the region. This flow pattern was due to persistent high pressure systems towards Svalbard’s east, with low pressure systems coming up from the southwest, pushing mild (and often humid) air towards the Archipelago.

Fastest warming place on earth

Svalbard is one of the fastest warming places on Earth. The reason for the faster-than-average warming is due to several feedbacks, such as the ice-albedo feedback. Even more, Svalbard is strongly affected by changes in ocean currents and shifts in wind patterns. Specifically, Svalbard ends up on the ‘warmer side’ of cyclones more frequently, and relatively warm Atlantic water penetrates further into the Svalbard region and its fjords, a process known as Atlantification.

read more about Longyearbyen’s climate here

Most of Svalbard’s warming has been concentrated in the winter months. Nevertheless, the last few summers have been astounding, with the summer of 2024 defying every statistical norm. 

 

[Typhoon Tip]

some are already aware but useful recap/nested links either way...

 

https://phys.org/news/2024-09-earth-hottest-summer.html

[chubbs]

August's ERA5 water precipitable water chart from Ben Noll. The chart is similar to previous months with moisture well-above pre-nino levels, continuing the relatively rapid rise in moisture over the past 10-15 years. The nino infuence should start to wane soon. We'll see if moisture drops back to pre-nino levels like most ninas; or, stays elevated like the 2015/16 nino.

[bluewave]

 

 

[GaWx]

2 hours ago, bluewave said:

 

 

 I continue to think that until it can be proven that it wasn’t the case that the enormous amount of additional water vapor blasted way up into the stratosphere by Hunga Tonga may have had a lot to do with this. Perhaps that combined with the solar max increasing upper tropospheric stability? Who’s to say that this couldn’t possibly have been the case as a major contributor when the cause(s) have yet to be proven?

[bluewave]

9 hours ago, GaWx said:

 I continue to think that until it can be proven that it wasn’t the case that the enormous amount of additional water vapor blasted way up into the stratosphere by Hunga Tonga may have had a lot to do with this. Perhaps that combined with the solar max increasing upper tropospheric stability? Who’s to say that this couldn’t possibly have been the case as a major contributor when the cause(s) have yet to be proven?

https://www.theclimatebrink.com/p/2024s-unusually-persistent-warmth

What might this mean going forward?

 

Unfortunately we still lack a good explanation for what drove the exceptional warmth the world saw in 2023 and 2024. We have a lot of potential mediocre explanations (e.g. low sulfur marine fuel regulations, the Hunga Tonga volcanic eruption in 2022, an uptick in the 11 year solar cycle, El Nino behaving weirdly, etc.). But these have increasingly been modeled, and it is hard to explain the magnitude of the global temperature anomaly the world has experienced even adding all of these estimates together.

[Typhoon Tip]

but they just explained it though ... ?

  all those working in concert and at varying amounts, produced a synergistic result.  i'm personally above the 90th percentile confident in that.  the problem with synergy is that it doesn't by mathematics have a linear cause - in other words, if one looks for the singular cause it is impossible to ever find it, because it does not exist.

i get the appeal to find a silver bullet cause, but given the objective reality over the earth being a result of a complex polynomial of indirectly/co-mingling forces, anyway,  it's pretty damning that all those factors also for constructively interfering complexity, led to the earth's temperature leap.

you know ... if anything, it's more probable that we were behind; what took place was more like an uncapping of erstwhile suppressive effects - not the other way around.  fascinating proposition, but perhaps any such erstwhile offset was only stopping the synergy product, perhaps only lending to observations looking more constrained.

[Terpeast]

2 hours ago, bluewave said:

https://www.theclimatebrink.com/p/2024s-unusually-persistent-warmth

What might this mean going forward?

 

Unfortunately we still lack a good explanation for what drove the exceptional warmth the world saw in 2023 and 2024. We have a lot of potential mediocre explanations (e.g. low sulfur marine fuel regulations, the Hunga Tonga volcanic eruption in 2022, an uptick in the 11 year solar cycle, El Nino behaving weirdly, etc.). But these have increasingly been modeled, and it is hard to explain the magnitude of the global temperature anomaly the world has experienced even adding all of these estimates together.

Like Tip said, I suspect that non linear effects are involved. If just “adding” these effects together along with CO2 wasn’t enough to explain the global temp spike, then either something else is going on and we missed it (unlikely)… or the combination of these effects isn’t additive but rather multiplicative or heaven forbid, exponential.

[TheClimateChanger]

Correct me if I'm wrong, but unless current warming is outside of the range of modeled projections, there's no need to consider any of these other factors and the warming can be fully explained by greenhouse gas emissions [and other factors already considered in the modeling].

[chubbs]

August GISS came in at 1.30C, another monthly record. The Jan-Aug mean is 1.29 well above last years record of 1.17. A new record this year is almost guaranteed, probably somewhere around 1.24 allowing for some cooling in the last 4 months. The left-hand chart will probably need a new yaxis.

[bluewave]

On 9/10/2024 at 8:31 AM, Terpeast said:

Like Tip said, I suspect that non linear effects are involved. If just “adding” these effects together along with CO2 wasn’t enough to explain the global temp spike, then either something else is going on and we missed it (unlikely)… or the combination of these effects isn’t additive but rather multiplicative or heaven forbid, exponential.

It could also be possible that this extreme mid-latitude SST warming is acting like a higher latitude version of an El Niño. So the past year we had a tropical and extra tropical El Niño at the same time. Perhaps the overlap between these two features is having an additive effect. 
 

 

[chubbs]

NOAA OIv2 SST including Sept to-date. Ticked up recently, as drop from nino peak continues to be slow. SST is consistent with the August precipitable water chart I posted above, with large increase in past 10-15 years.

[bluewave]

 

 

[chubbs]

After a two month hiatus OI SST is back at record levels. Unusual this far into a nino-->nina transition

[bluewave]