Menu

risk

Extreme weather in a changing climate

, , , , , , , , , , , , , ,

 

First published 19 September 2023, in Environmental Research Letters 18; reproduced here under Creative Commons Attribution 4.0 licence

Authors:

  1. Giorgia Di Capua:Magdeburg-Stendal University of Applied Sciences, 39114 Magdeburg, Germany

  2. Stefan Rahmstorf: Potsdam Institute for Climate Impact Research (PIK), Member of the Leibniz Association, PO Box 6012 03, D-14412 Potsdam, Germany | E-mail: [email protected]

Abstract

Extreme weather events are rising at a pace which exceeds expectations based on thermodynamic arguments only, changing the way we perceive our climate system and climate change issues. Every year, heatwaves, floods and wildfires, bring death and devastation worldwide, increasing the evidence about the role of anthropogenic climate change in the increase of extremes. In this viewpoint article, we summarize some of the most recent extremes and put them in the context of the most recent research on atmospheric and climate sciences, especially focusing on changes in thermodynamics and dynamics of the atmosphere. While some changes in extremes are to be expected and are clearly attributable to rising greenhouse gas emissions, other seem counterintuitive, highlighting the need for further research in the field. In this context, research on changes in atmospheric dynamics plays a crucial role in explaining some of these extremes and more needs to be done to improve our understanding of the physical mechanisms involved.

_______________________________________

A rise in weather extremes is probably the most severe early impact of rising global temperatures. Extreme weather events have a high impact on both human activities and natural ecosystems. In recent decades the world has seen an increase in heatwaves, droughts, flooding events and fire weather conditions, as expected in a warming climate. 2022 has been no exception, with record-breaking high temperatures registered across large portions of Western Europe, China and Pakistan (Hausfather 2023). In Pakistan, extreme monsoon rains and Himalayan glaciers melting away in a heat wave have flooded approximately 85 000 km2 (USAID 2022), killing more than 1700 people and causing $15 billion of damage (World Bank), while the Horn of Africa has seen an unprecedented drought that has pushed more than three million people into emergency food insecurity (NASA Earth Observatory 2022). Many of these events have been made more likely by anthropogenic warming and represent a serious threat to human society, with effects ranging from health and mortal- ity to economy and national security issues.

Even for lay persons it will be obvious that heat extremes will increase in a warming world. But it may be unexpected by how much: monthly heat extremes

that were three standard deviations above average during the baseline period 1951–1980 have already increased over 90-fold in frequency over the global land area, while the formerly near-unprecedented 4-sigma events have increased 1000-fold to affect 3% of the land area in any given month, data show (Robinson et al 2021). July 2023 was the hot- test month on record on Earth by a large margin (Copernicus 2023a), and likely the hottest for at least 10 000 years. Marine heatwaves have also doubled in the last few decades, and they are expected to see a 23-fold increase under a 2 ◦C warming scenario (Frölicher et al 2018)—the off-the charts sea surface temperatures in the North Atlantic in summer 2023 are a stern foretaste of this (Copernicus 2023b), while in Florida the marine heatwave caused wide spread bleaching turning into one of the worst events in the region on record (Dennis et al 2023).

Part of this is as expected simply by shifting a Gaussian normal distribution towards warmer values; the more extreme an event, the larger is the factor by which its likelihood increases. However, explaining the full extent of the global increase in extreme heat requires additional, dynamical effects (which we will discuss below).

And heat—especially lasting heat—is a silent killer. The death toll of the 2003 European heat wave has been estimated as ∼70 000 (Robine et al 2008), with a mortality peak in France higher than dur- ing any Covid19 wave (Ferrer and Breteau 2020). A first estimate for summer 2022 came in at ∼62 000 (Ballester et al 2023), when even in Britain temperatures soared above 40◦C for the first time in history. Temperature-related excess mortality is expected to increase with unmitigated global warming, even when accounting for a decrease in cold-related deaths (Gasparrini et al 2017).

Since early 2012, the fingerprint of climate change can be detected in any single day in the observed record. There are no more days on Earth where global weather is not significantly different from what it would be without human influence—on nearly all days even when just considering the weather pat- terns without the increase in global-mean temperature (Sippel et al 2020). Observations show that nearly the entire Earth surface has warmed since the late 19th century (except for the prominent ‘warming hole’ south of Greenland and Iceland, Rahmstorf et al 2015) and the annual global mean temperature has increased by 1.2◦C since the late 19th Century (Intergovernmental Panel on Climate Change 2021). The intensity and speed of warming differ by region, with land areas warming twice as much as the ocean surface since 1970 (Intergovernmental Panel on Climate Change 2021). Warming is more prominent in the Arctic, Eastern Europe, North Africa, the Middle East, East Asia and western North America. Key heatwave characteristics, such as frequency, duration and cumulative heat (i.e. the heat produced by heatwaves days inside a season), show increasing trends since 1950 at global scale, with stronger trends in tropical and northern latitudes. Trends for these key variables have been accelerating in the past few decades (Perkins-Kirkpatrick and Lewis 2020). Summer 2023 was no exception, with record breaking temperature recorded in Southeastern US, China, Spain, Morocco, rendered more likely by current climate change (Zachariah et al 2023).

While the world-wide rise in heat extremes is easily understood given the rise in global mean temperature, mean global rainfall and extreme precipitation trends depict a more complex relationship. Global rainfall is expected to increase as evaporation from warmer oceans increases. Indeed, the IPCC AR6 WGI (2021) reports an increase in globally averaged land precipitation since 1950, though with medium confidence given the large variability and spatial heterogeneity of precipitation. However, extreme rainfall events have shown a steep increase in the last few decades (especially in tropical regions), with 1 in 4 record breaking rainfall events being attributable to climate change (Robinson et al 2021). In August 2023, the region surrounding Beijing was hit by a severe flood event which saw the highest rainfall record of

the last 140 years (744.8 mm in less the 4 d) (Hawkins 2023) Perhaps counterintuitively, some areas even show opposite trends in mean precipitation rates and extreme rainfall events. One such example is the Indian summer monsoon system, which shows a slight decrease in its mean seasonal precipitation rates together with a three-fold increase in extreme rainfall events during the 1950–2015 period (Roxy et al 2017). Therefore, when considering the effect of climate change on extremes, it is not enough to look at trends in mean values.

Another example of that is that despite the global-mean (and often also local) rainfall increase, the frequency and severity of droughts has also increased in some regions, for a number of reasons. One overall reason is that with approximately constant relative humidity, air will contain (and at some point rain out) 7% more moisture per degree of warming, while the resupply of water via evaporation increases only by 2%–3% per degree (Allan et al 2020). The additional evaporation and rain- fall tends to end up in heavy rain rather than alleviating drought: Half of it comes down in the wet- test 6 d each year (Pendergrass and Knutti 2018), and the heaviest rainfall events increase most strongly (Fischer and Knutti 2015). Also, increasing agricultural and ecological droughts (i.e. loss of soil moisture and drying vegetation) can be caused not just by declining precipitation but also by rising temperatures causing faster evapotranspiration. In different regions, either of these effects can be the more important one (Cook et al 2018). Major droughts can also result from natural climate variability and are rare events (compared to the length of available observational data). Thus, studying their trend and, more importantly, attributing them to anthropogenic global warming is not an easy task (Cook et al 2018). Several regions in the world have shown an increase in drought risk, such as Western North America, the Mediterranean, East Southern Africa, East Asia and South Australia, at least partly attributable to anthropogenic warming, with the Mediterranean and the North-Western North America showing the highest confidence (Intergovernmental Panel on Climate Change 2021).

In the past decade, wildfire activity has produced some new extreme fires that are unprecedented regarding propagation speed, intensity, location, timing and burnt area (Descals et al 2022, Senande- Rivera et al 2022). For example, the Australian ‘Black Summer’ wildfire disaster in 2019/2020 fol- lowed Australia’s hottest and driest year on record, burned more than half of the habitat for over 1600 native species and directly caused 33 human deaths and almost 450 more from smoke inhalation (Himbrechts 2021). An increase in extreme fire weather conditions can already be detected at global scale, although trend magnitude and spatial patterns vary at regional scale (Jain et al 2022). Globally, anthropogenic global warming is projected to cause unprecedented increases in extreme fire weather risk in the 21st century (Touma et al 2021). Model experiments estimate that anthropogenic induced changes in fire weather indices have already emerged from natural variability for 22% of the burnable land area globally by 2019, while by the mid twenty-first century the emergence will reach 30%–60% (Abatzoglou et al 2019). Meanwhile, in August 2023, Hawaii has experienced its worst wildfire on record, and one of the worst in US history, where dry conditions and hurricane-force winds fueled the flames bringing utter devastation to the town of Lahaina, killing at least 93 people and thus surpassing the death toll of the Camp fire in California in 2018 (Gabbat and Anguiano 2023).

While warm extremes are to be expected due to anthropogenic global warming, cold extreme are projected to decrease in this century. Nevertheless, despite the general increase in global surface temperatures, a few regions show a cooling trend in the historical record. One such example is central Siberia, which features a cooling trend during boreal winter (Inoue et al 2012). While both natural variability and anthropogenic forcing are debated as causes of this trend (Inoue et al 2012), the cooling trend is mainly associated with an increase in cold extremes over the region. Cold air outbreaks in central Siberia and North America have been shown to result from sudden stratospheric warming events and a disruption of the stratospheric Polar vortex (Kretschmer et al 2018).

Detecting climate change signals can be challenging depending on the region and the variable selected, and attributing trends in temperature or precipitation fields to changes in thermodynamic or dynamic features of the atmosphere represent an even greater challenge (Shepherd 2014). In general, the largest portion of the change is to be attributed to thermodynamic effects. However, dynamic changes can further exacerbate thermodynamic driven changes and atmosphere dynamics and changes in weather patterns play an important role at regional scale (Rousi et al 2022). Amplified Rossby waves with preferred phase position, in particular waves with wave numbers 5 and 7, can lead to concurrent heatwaves (and crop failures) in the mid-latitudes (Kornhuber et al 2020), raising concerns about future food security. Arctic amplification, despite being more prominent in winter than summer, may also affect westerly winds, storm tracks and wave-guides in the mid-latitudes (Coumou et al 2018). Analyzing the ability of models to reproduce amplified waves 5 and 7 shows that even a small bias in upper tropospheric circulation features can have a strong impact on surface temperature and rainfall patterns (Luo et al 2022), highlighting that it is difficult for global climate models to simulate all mechanisms that contribute to making weather more extreme.

Europe has emerged as a hot-spot of heat extremes: it has seen a stronger increase in summer heat than other regions in the northern mid-latitudes. This enhanced warming has been related to dynamical changes such as an increase of double jet patterns, which could explain all of the additional rise in heat waves beyond what is expected simply by thermodynamics (Rousi et al 2022). Both observation and model experiment support the hypothesis that shrinking Arctic sea ice and reduced snow cover over northern Eurasia in spring can also contribute to increased blocking over Europe and consequent frequency of heatwaves (Zhang et al 2020). Sea surface temperature anomalies (in particular the northern Atlantic ‘warming hole’ mentioned earlier) can also reinforce heatwaves in central Europe, such as in 2015 (Duchez et al 2015).

In summary, it is now clear that global warming is already greatly increasing the number and intensity of many types of weather extremes, as has been predicted by climate science for decades. Much of this is due to thermodynamics. With that we mean that the atmosphere is warmer, which means it holds more energy and water to power extreme weather. The ocean is also warmer and can provide more energy and moisture as fuel to tropical cyclones. However, increasingly the attention of researchers has turned to dynamic effects. With that we refer to changes in circulation and stability of atmosphere and ocean. It includes changes to the jet stream, polar vortex, atmospheric planetary waves or to the Atlantic meridional overturning circulation.

Obtaining robust conclusions about changes in weather extremes requires long time series, given that extreme events are by definition rare events and are not easy to model. Nevertheless, the signal of climate change has now clearly emerged from the noise for many types of extremes. Disentangling the dynamic mechanisms is harder again and represents a current frontline of research. Driving forces behind dynamic changes are often regionally diverse temperature changes, such as Arctic amplification, enhanced land warming and sea surface temperature anomalies. Many facets of the dynamic mechanisms are still being debated in the scientific literature. Even if not everything is fully understood, researchers and journalists should not be shy to use every opportunity to educate the public about the fact that human-caused global warming is making weather extremes worse, already causing serious harm to many millions of people.

Even once global warming is stopped, we will see unprecedented extremes for a long time to come. Just think of a former once-in-5000 year event which at 1.5◦C warming may have become a once-in-50 year event. Thus, it will take many decades until we have seen all the possible extreme events a 1.5◦C warmer world has in store for us.


References

Abatzoglou J T, Williams A P and Barbero R 2019 Global emergence of anthropogenic climate change in fire weather indices Geophys. Res. Lett. 46 326–36

Allan R P et al 2020 Advances in understanding large-scale responses of the water cycle to climate change Ann. New York Acad. Sci. 1472 49–75

Ballester J, Quijal-zamorano M, Fernando R, Turrubiates M, Pegenaute F, Herrmann F R, Robine J M and Basagan ̃a X 2023 Heat-related mortality in Europe during the summer of 2022 Nat. Med. 29 1857–66

Cook B I, Mankin J S and Anchukaitis K J 2018 Climate change and drought: from past to future Curr. Clim. Change Rep. 4 164–79

Copernicus 2023a July 2023 sees multiple global temperature records broken Copernicus (available at: https://climate. copernicus.eu/july-2023-sees-multiple-global-temperature- records-broken)

Copernicus 2023b Record-breaking North Atlantic Ocean temperatures contribute to extreme marine heatwaves Copernicus Online (available at: https://climate.copernicus. eu/record-breaking-north-atlantic-ocean-temperatures- contribute-extreme-marine-heatwaves)

Coumou D, Di Capua G, Vavrus S, Wang L and Wang S 2018 The influence of Arctic amplification on mid-latitude summer circulation Nat. Commun. 9 2959

Dennis B, Ajasa A and Mooney C 2023 As Florida ocean temperatures soar, a race to salvage imperiled corals (Washington Post) (available at: www.washingtonpost.com/ climate-environment/2023/07/26/florida-coral-reef-ocean- temperatures-heat/)

Descals A, Gaveau D L A, Verger A, Sheil D, Naito D and Pen ̃uelas J 2022 Unprecedented fire activity above the Arctic circle linked to rising temperatures Science 378 532–7

Duchez A, Frajka-williams E, Josey S A, Evans D G, Grist J P, Marsh R, McCarthy G D, Sinha B, Berry D I and Hirschi J J-M 2015 Drivers of exceptionally cold North Atlantic Ocean temperatures and their link to the 2015 European heat wave Environ. Res. Lett. 11 1–9

Ferrer M and Breteau P 2020 Coronavirus: un pic très net de mortalité en France enregistré en mars et avril Le Monde (available at: www.lemonde.fr/les-decodeurs/article/2020/ 04/27/coronavirus-un-pic-tres-net-de-mortalite-en-france- depuis-le-1er-mars-par-rapport-aux-vingt-dernieres- annees_6037912_4355770.html)

Fischer E M and Knutti R 2015 Anthropogenic contribution to global occurrence of heavy-precipitation and high-temperature extremes Nat. Clim. Change 5 560–4

Frölicher T L, Fischer E M and Gruber N 2018 Marine heatwaves under global warming Nature 560 360–4

Gabbat A and Anguiano D 2023 Hawaii wildfires: deadliest US blaze in a century kills at least 93 people Guard (available at: www.theguardian.com/us-news/2023/aug/13/hawaii- wildfires-at-least-89-confirmed-killed-after-deadliest-us- blaze-in-100-years)

Gasparrini A et al 2017 Projections of temperature-related excess mortality under climate change scenarios Lancet Planet. Health 1 e360–7

Hausfather Z 2023 State of the climate: how the world warmed in 2022 Carbon Brief (available at: www.carbonbrief.org/state- of-the-climate-how-the-world-warmed-in-2022/)

Hawkins A 2023 Chinese firefighter ‘dies heroic death’ as Beijing reports heaviest rain in 140 years Guard (available at: www. theguardian.com/world/2023/aug/02/beijing-reports- heaviest-rain-140-years-china-g20-climate-talks)

Himbrechts D 2021 Australia’s Black Summer of fire was not normal—and we can prove it The Conversation (available at: https://theconversation.com/australias-black-summer-of- fire-was-not-normal-and-we-can-prove-it-172506)

Inoue J, Hori M E and Takaya K 2012 The role of Barents Sea ice in the wintertime cyclone track and emergenceof a warm-Arctic cold-Siberian anomaly J. Clim. 25 2561–9

IPCC 2021 Climate Change 2021: The Physical Science Basis.

Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change ed V Masson-Delmotte et al (Cambridge University Press) (https://doi.org/10.1017/9781009157896)

Jain P, Castellanos-Acuna D and Coogan S C P 2022 Observed increases in extreme fire weather driven by atmospheric humidity and temperature Nat. Clim. Chang. 12 63–70

Kornhuber K, Coumou D, Vogel E, Lesk C, Donges J F, Lehmann J and Horton R M 2020 Amplified Rossby waves enhance risk of concurrent heatwaves in major breadbasket regions Nat. Clim. Change 20 48–53

Kretschmer M, Cohen J, Matthias V, Runge J and Coumou D 2018 The different stratospheric influence on cold-extremes in Eurasia and North America npj Clim. Atmos. Sci. 1 1–10

Luo F et al 2022 Summertime Rossby waves in climate models: substantial biases in surface imprint associated with small biases in upper-level circulation Weather Clim. Dyn.
3 905–35

NASA Earth Observatory 2022 Worst Drought on Record Parches Horn of Africa (available at: https://earthobservatory.nasa. gov/images/150712/worst-drought-on-reco)

Pendergrass A G and Knutti R 2018 The uneven nature of daily precipitation and its change Geophys. Res. Lett.
45 980–11,988

Perkins-Kirkpatrick S E and Lewis S C 2020 Increasing trends in regional heatwaves Nat. Commun. 11 1–8

Rahmstorf S, Box J E, Feulner G, Mann M E, Robinson A, Rutherford S, Scha E J and Schaffernicht E J 2015 Exceptional twentieth-century slowdown in Atlantic Ocean overturning circulation Nat. Clim. Change 5 475–80

Robine J M, Cheung S L K, Le Roy S, Van Oyen H, Griffiths C, Michel J P and Herrmann F R 2008 Death toll exceeded 70,000 in Europe during the summer of 2003 C. R. Biol. 331 171–8

Robinson A, Lehmann J, Barriopedro D, Rahmstorf S and Coumou D 2021 Increasing heat and rainfall extremes now far outside the historical climate npj Clim. Atmos. Sci. 4 3–6

Rousi E, Kornhuber K, Beobide-Arsuaga G, Luo F and Coumou D 2022 Accelerated western European heatwave trends linked to more-persistent double jets over Eurasia Nat. Commun. 13 1–11

Roxy M K, Ghosh S, Pathak A, Athulya R, Mujumdar M, Murtugudde R, Terray P and Rajeevan M 2017 A threefold rise in widespread extreme rain events over central India Nat. Commun. 8 1–11

Senande-Rivera M, Insua-Costa D and Miguez-Macho G 2022 Spatial and temporal expansion of global wildland fire activity in response to climate change Nat. Commun.
13 1–9

Shepherd T G 2014 Atmospheric circulation as a source of uncertainty in climate change projections Nat. Geosci. 7 703–8

Sippel S, Meinshausen N, Fischer E M, Székely E and Knutti R 2020 Climate change now detectable from any single day of weather at global scale Nat. Clim. Change 10 35–41

Touma D, Stevenson S, Lehner F and Coats S 2021 Human-driven greenhouse gas and aerosol emissions cause distinct regional impacts on extreme fire weather Nat. Commun. 12 1–8

USAID 2022 Pakistan Flood Fact Sheet (available at: www.usaid. gov/sites/default/files/2022-12/2022-09- 30_USG_Pakistan_Floods_Fact_Sheet_8.pdf)

Zachariah M, Philip S, Pinto I, Vahlberg M, Singh R, Arrighi J R, Barne C and Otto F E L 2023 Extreme heat in North America, Europe and China in July 2023 made much more likely by climate change (https://doi.org/10.25561/105549)

Zhang R, Sun C, Zhu J, Zhang R and Li W 2020 Increased European heat waves in recent decades in response to shrinking Arctic sea ice and Eurasian snow cover npj Clim. Atmos. Sci. 3 7

wildfire image: Malachi Brooks

, , , , , ,

Port Hills is only the beginning


This article is republished from The Conversation under a Creative Commons license. Read the original article.

___________________________________________________________________________________


Last week, wildfire burnt through 650 hectares of forest and scrub in Christchurch’s Port Hills. This is not the first time the area has faced a terrifying wildfire event.

The 2017 Port Hills fires burnt through almost 2,000 hectares of land, claiming one life and 11 homes. It took 66 days before the fires were fully extinguished.

It is clear New Zealand stands at a pivotal juncture. The country faces an increasingly severe wildfire climate. And our once relatively “safe” regions are now under threat.

At all levels of government, New Zealand needs to consider whether our current investment to combat fires will be enough in the coming decades.

Our research integrating detailed climate simulations with daily observations reveals a stark forecast: an uptick in both the frequency and intensity of wildfires, particularly in the inland areas of the South Island.

It is time to consider what this will mean for Fire and Emergency New Zealand (FENZ), and how a strategic calibration of resources, tactics and technologies will help New Zealand confront this emerging threat.

The climate drivers of wildfires

Last year was the warmest year on record by a large margin. And with El Niño at full throttle into 2024, conditions in late-summer Aotearoa New Zealand are hot and dry. There is also plenty of vegetation fuel from the departing wet La Niña.

The tinder-dry scrub and grass vegetation in the Port Hills – an area that was around 30% above “extreme” drought fire danger thresholds – drove the flammability of the region. And on February 13, when the latest fires started, a strong gusty northwesterly wind was blowing 40-50kph with exceptionally dry relative humidity values.

These conditions resulted in the extreme wildfire behaviour. Only the rapid and coordinated response of FENZ on the ground and in the air prevented this fire from becoming much worse.

While conditions are already bad, our study revealed a concerning trend: the widespread emergence of a new wildfire climate, with regions previously unaffected by “very extreme” wildfire conditions now facing unprecedented threats.

The most severe dangers are projected for areas like the Mackenzie Country, upper Otago and Marlborough, where conditions similar to Australia’s “Black Summer” fires could occur every three to 20 years.

This shift is not merely an environmental concern, it is a socioeconomic one. The increased threat of wildfires will affect communities, the government’s tree-planting initiatives and financial investments in carbon forests.

Enhanced resources and agile response

New Zealand’s firefighting strategy emphases speed and manoeuvrability, especially in the initial attack phase, to prevent wildfires from escalating into large-scale disasters.

Approximately NZ$10 million is allocated annually to general firefighting aviation services, translating into around 11,000 flight hours. The aerial battle over the Port Hills peaked on Thursday and Friday. This effort cost over $1 million, with up to 15 helicopters active over the two days.

FENZ operations are primarily funded by property insurance levies. However, with the severity and frequency of wildfires on the rise, it may be necessary to review this funding model to match the evolving risk portfolio.

Climate change is already driving insurance retreat – a phenomenon whereby coastal properties are unable to renew their insurance due sea level rise. It is plausible insurance companies could take a similar stance in extremely fire-prone areas.

The agility of FENZ and associated rural fire teams, coupled with the investment and integration of advanced technologies and modelling for better wildfire prediction and management, can significantly enhance the effectiveness of firefighting efforts.

Policy adjustments and community engagement

Adjustments in policy and regulatory frameworks are also crucial in mitigating wildfire risks, and should be explored by experts.

To significantly reduce the ignition of new fires, there needs to be greater implementation of restrictions on access, and banning of high-risk activities, when areas are under “extreme fire risk”.

Moreover, community engagement and preparedness initiatives are vital. One successful example is Mt Iron, Wanaka, where a model was developed after interviews, focus groups and workshops with residents identified wildfire risk awareness and mitigation actions.

Educating vulnerable communities about their wildfire risks and preparedness strategies can also enhance community resilience and safety.

The emergence of a more severe wildfire climate in New Zealand calls for a unified response, integrating increased investment in FENZ, strategic planning and community involvement.

By embracing a multifaceted approach that includes technological innovation, enhanced resource, and community empowerment, New Zealand can navigate the complexities of this new era with resilience and foresight.The Conversation

Carbon trading

, , , , , , , , ,

From The Guardian: read the full article by Nina Lakhani
 
“The Guardian and researchers from Corporate Accountability, a non-profit, transnational corporate watchdog, analysed the top 50 emission offset projects, those that have sold the most carbon credits in the global market.

“According to our criteria and classification system:

  • A total of 39 of the top 50 emission offset projects, or 78% of them, were categorised as likely junk or worthless due to one or more fundamental failing that undermines its promised emission cuts.
  • Eight others (16%) look problematic, with evidence suggesting they may have at least one fundamental failing and are potentially junk, according to the classification system applied.
  • The efficacy of the remaining three projects (6%) could not be determined definitively as there was insufficient public, independent information to adequately assess the quality of the credits and/or accuracy of their claimed climate benefits.

“Overall, $1.16bn (£937m) of carbon credits have been traded so far from the projects classified by the investigation as likely junk or worthless; a further $400m of credits bought and sold were potentially junk.” – keep reading

Infographic: How are carbon offsets supposed to work?

Carbon Brief have also released a detailed analysis and mapping, including carbon credits claims made by New Zealand companies:
 
Carbon Brief's infographic: carbon offset claims
Carbon Brief’s infographic: carbon offset claims
Climate change event attribution - wildfire: image Mike Newbry

, , , , ,

Podcast hosted by: Joelle Gergis, Australian National University and Michael Green, The Conversation

Interviewed: Honorary Professor, The University of Melbourne;  Senior Lecturer in Climate Science, Imperial College London, Tannecia Stephenson Physics Professor, University of the West Indies, Mona Campus

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Last month the United Nations’ Intergovernmental Panel on Climate Change (IPCC) released its Synthesis Report of the Sixth Assessment Report.

It showed global temperatures are now 1.1℃ above pre-industrial levels. This warming has driven widespread and rapid global changes, including more frequent and intense weather extremes that are now impacting people and ecosystems all over the world.

But when an extreme weather event hits, how certain can we be that it was made more likely by climate change? How do we know it wasn’t just a rare, naturally-occuring event that might have happened anyway?

Fear & Wonder is a new podcast from The Conversation that takes you inside the UN’s era-defining climate report via the hearts and minds of the scientists who wrote it.

The show is hosted by Dr Joëlle Gergis – a climate scientist and IPCC lead author – and award-winning journalist Michael Green.

In this episode, we’re delving into one of the major shifts in the public communication of climate change – the attribution of extreme weather events to climate change.

Although in the past we knew climate change was making extreme weather more likely, advances in climate modelling now allow scientists to pinpoint the influence of natural and human-caused factors on individual weather extremes.

We speak to climatologist Dr Friederike Otto about a rapid attribution study of a heatwave in Toulouse, France, as it unfolded in 2019. We also hear from climatologist Professor David Karoly to help us understand how climate models actually work, while Professor Tannecia Stephenson explains how global models are then used to develop regional climate change projections over the Caribbean island of Jamaica.

To listen and subscribe, click here, or click the icon for your favourite podcast app in the graphic above.

Fear and Wonder is sponsored by the Climate Council, an independent, evidence-based organisation working on climate science, impacts and solutions.The Conversation

Antarctic sea ice: Edward Doddridge, Australian Antarctic Program

, , , , , , , , ,

By: Edward Doddridge, Research Associate in Physical Oceanography, University of Tasmania

This article is republished from The Conversation under a Creative Commons license. Read the original article.

The rhythmic expansion and contraction of Antarctic sea ice is like a heartbeat.

But lately, there’s been a skip in the beat. During each of the last two summers, the ice around Antarctica has retreated farther than ever before.

And just as a change in our heartbeat affects our whole body, a change to sea ice around Antarctica affects the whole world.

Today, researchers at the Australian Antarctic Program Partnership (AAPP) and the Australian Centre for Excellence in Antarctic Science (ACEAS) have joined forces to release a science briefing for policy makers, On Thin Ice.

Together we call for rapid cuts to greenhouse gas emissions, to slow the rate of global heating. We also need to step up research in the field, to get a grip on sea-ice science before it’s too late.

The shrinking white cap on our blue planet

One of the largest seasonal cycles on Earth happens in the ocean around Antarctica. During autumn and winter the surface of the ocean freezes as sea ice advances northwards, and then in the spring the ice melts as the sunlight returns.

We’ve been able to measure sea ice from satellites since the late 1970s. In that time we’ve seen a regular cycle of freezing and melting. At the winter maximum, sea ice covers an area more than twice the size of Australia (roughly 20 million square kilometres), and during summer it retreats to cover less than a fifth of that area (about 3 million square km).

In 2022 the summer minimum was less than 2 million square km for the first time since satellite records began. This summer, the minimum was even lower – just 1.7 million square km.

The annual freeze pumps cold salty water down into the deep ocean abyss. The water then flows northwards. About 40% of the global ocean can be traced back to the Antarctic coastline.

By exchanging water between the surface ocean and the abyss, sea ice formation helps to sequester heat and carbon dioxide in the deep ocean. It also helps to bring long-lost nutrients back up to the surface, supporting ocean life around the world.

Not only does sea ice play a crucial role in pumping seawater across the planet, it insulates the ocean underneath. During the long days of the Antarctic summer, sunlight usually hits the bright white surface of the sea ice and is reflected back into space.

This year, there is less sea ice than normal and so the ocean, which is dark by comparison, is absorbing much more solar energy than normal. This will accelerate ocean warming and will likely impede the wintertime growth of sea ice.

Headed for stormy seas

The Southern Ocean is a stormy place; the epithets “Roaring Forties” and “Furious Fifties” are well deserved. When there is less ice, the coastline is more exposed to storms. Waves pound on coastlines and ice shelves that are normally sheltered behind a broad expanse of sea ice. This battering can lead to the collapse of ice shelves and an increase in the rate of sea level rise as ice sheets slide off the land into the ocean more rapidly.

Sea ice supports many levels of the food web. When sea ice melts it releases iron, which promotes phytoplankton growth. In the spring we see phytoplankton blooms that follow the retreating sea ice edge. If less ice forms, there will be less iron released in the spring, and less phytoplankton growth.

Krill, the small crustaceans that provide food to whales, seals, and penguins, need sea ice. Many larger species such as penguins and seals rely on sea ice to breed. The impact of changes to the sea ice on these larger animals varies dramatically between species, but they are all intimately tied to the rhythm of ice formation and melt. Changes to the sea-ice heartbeat will disrupt the finely balanced ecosystems of the Southern Ocean.

Three Adelie penguins and a leopard seal on the sea ice
Sea ice provides habitat for marine life, ranging in size from microbes to the largest animals on the planet. Here Adelie penguins approach a leopard seal. Wendy Pyper AAD, Author provided


A diagnosis for policy makers

Long term measurements show the subsurface Southern Ocean is getting warmer. This warming is caused by our greenhouse gas emissions. We don’t yet know if this ocean warming directly caused the record lows seen in recent summers, but it is a likely culprit.

As scientists in Australia and around the world work to understand these recent events, new evidence will come to light for a clearer understanding of what is causing the sea ice around Antarctica to melt.

A chart of monthly sea ice extent showing the difference between the long-term average sea ice and the observed sea ice in each month

Antarctic sea ice is highly variable, but there has been less ice than normal for almost all of the last seven years. This chart of monthly sea ice extent anomaly shows the difference between the long-term average sea ice and the observed sea ice in each month. By removing the annual cycle due to sea ice formation and melt, we can see the longer term variability underneath, and the extreme low sea ice events in recent years. Dr Phil Reid, BoM, Author provided

If you noticed a change in your heartbeat, you’d likely see a doctor. Just as doctors run tests and gather information, climate scientists undertake fieldwork, gather observations, and run simulations to better understand the health of our planet.

This crucial work requires specialised icebreakers with sophisticated observational equipment, powerful computers, and high-tech satellites. International cooperation, data sharing, and government support are the only ways to provide the resources required.

After noticing the first signs of heart trouble, a doctor might recommend more exercise or switching to a low-fat diet. Maintaining the health of our planet requires the same sort of intervention – we must rapidly cut our consumption of fossil fuels and improve our scientific capabilities.The Conversation

Glacier terminal undercut by warm water image by Sonny Whitelaw

, , , , , , , , ,

By: Christine Batchelor, Lecturer in Physical Geography, Newcastle University and Frazer Christie, Postdoctoral Research Associate, University of Cambridge

This article is republished from The Conversation under a Creative Commons license. Read the original article.

The Antarctic Ice Sheet, which covers an area greater than the US and Mexico combined, holds enough water to raise global sea level by more than 57 metres if melted completely. This would flood hundreds of cities worldwide. And evidence suggests it is melting fast. Satellite observations have revealed that grounded ice (ice that is in contact with the bed beneath it) in coastal areas of West Antarctica has been lost at a rate of up to 30 metres per day in recent years.

But the satellite record of ice sheet change is relatively short as there are only 50 years’ worth of observations. This limits our understanding of how ice sheets have evolved over longer periods of time, including the maximum speed at which they can retreat and the parts that are most vulnerable to melting.

So, we set out to investigate how ice sheets responded during a previous period of climatic warming – the last “deglaciation”. This climate shift occurred between roughly 20,000 and 11,000 years ago and spanned Earth’s transition from a glacial period, when ice sheets covered large parts of Europe and North America, to the period in which we currently live (called the Holocene interglacial period).

During the last deglaciation, rates of temperature and sea-level rise were broadly comparable to today. So, studying the changes to ice sheets in this period has allowed us to estimate how Earth’s two remaining ice sheets (Greenland and Antarctica) might respond to an even warmer climate in the future.

Our recently published results show that ice sheets are capable of retreating in bursts of up to 600 metres per day. This is much faster than has been observed so far from space.

Pulses of rapid retreat

Our research used high-resolution maps of the Norwegian seafloor to identify small landforms called “corrugation ridges”. These 1–2 metre high ridges were produced when a former ice sheet retreated during the last deglaciation.

Tides lifted the ice sheet up and down. At low tide, the ice sheet rested on the seafloor, which pushed the sediment at the edge of the ice sheet upwards into ridges. Given that there are two low tides each day off Norway, two separate ridges were produced daily. Measuring the space between these ridges enabled us to calculate the pace of the ice sheet’s retreat.

During the last deglaciation, the Scandinavian Ice Sheet that we studied underwent pulses of extremely rapid retreat – at rates between 50 and 600 metres per day. These rates are up to 20 times faster than the highest rate of ice sheet retreat that has so far been measured in Antarctica from satellites.

The highest rates of ice sheet retreat occurred across the flattest areas of the ice sheet’s bed. In flat-bedded areas, only a relatively small amount of melting, of around half a metre per day, is required to instigate a pulse of rapid retreat. Ice sheets in these regions are very lightly attached to their beds and therefore require only minimal amounts of melting to become fully buoyant, which can result in almost instantaneous retreat.

However, rapid “buoyancy-driven” retreat such as this is probably only sustained over short periods of time – from days to months – before a change in the ice sheet bed or ice surface slope farther inland puts the brakes on retreat. This demonstrates how nonlinear, or “pulsed”, the nature of ice sheet retreat was in the past.

This will likely also be the case in the future.

A warning from the past

Our findings reveal how quickly ice sheets are capable of retreating during periods of climate warming. We suggest that pulses of very rapid retreat, from tens to hundreds of metres per day, could take place across flat-bedded parts of the Antarctic Ice Sheet even under current rates of melting.

This has implications for the vast and potentially unstable Thwaites Glacier of West Antarctica. Since scientists began observing ice sheet changes via satellites, Thwaites Glacier has experienced considerable retreat and is now only 4km away from a flat area of its bed. Thwaites Glacier could therefore suffer pulses of rapid retreat in the near future.

Ice losses resulting from retreat across this flat region could accelerate the rate at which ice in the rest of the Thwaites drainage basin collapses into the ocean. The Thwaites drainage basin contains enough ice to raise global sea levels by approximately 65cm.

The Fimbul Ice Shelf in East Antarctica.
The Fimbul Ice Shelf in East Antarctica. Christine Batchelor, Author provided


Our results shed new light on how ice sheets interact with their beds over different timescales. High rates of retreat can occur over decades to centuries where the bed of an ice sheet deepens inland. But we found that ice sheets on flat regions are most vulnerable to extremely rapid retreat over much shorter timescales.

Together with data about the shape of ice sheet beds, incorporating this short-term mechanism of retreat into computer simulations will be critical for accurately predicting rates of ice sheet change and sea-level rise in the future.The Conversation

Nitrogen fertliser, being added to bare earth, Canterbury, adding to climate change as it converts to nitrous oxide

, , , , , , , , , ,


By: Anita Wreford, Lincoln University, New Zealand; John Tobias Saunders, Lincoln University, New Zealand, and Meike Guenther, Lincoln University, New Zealand

 Republished in full from The Conversation under a Creative Commons license. See the original article: April 12, 2023


The recent report issued by the Intergovernmental Panel on Climate Change (IPCC) underscores the urgency of emissions reductions. For Aotearoa New Zealand, where 50% of emissions come from agriculture in the form of methane and nitrous oxide, this means the primary sector must be part of the response.

New Zealand is indeed the first country to investigate introducing a price on agricultural greenhouse gas emissions.

The most recent pricing proposals would require farmers to pay a levy on their agricultural emissions. To begin with, only 5% of emissions would be priced, with proposals to reduce the 95% free allocation gradually over time.

Much of the existing modelling shows emissions could be cut by up to 10% by reducing the intensity of production, often through lowering animal numbers and fertiliser use. This doesn’t necessarily mean lower profitability. With good pasture management, farmers may be able to reduce stocking rates and increase profits.

But Aotearoa is already one of the most efficient producers of meat and dairy products globally. If we reduce emissions here, will that not simply lead to other, less efficient countries picking up the lost production, while our farmers pay the price?

This idea is known as “carbon leakage” and is often used as an argument against any domestic policy that could result in reduced agricultural production. The issue is important as New Zealand depends heavily on agricultural exports. In 2022, of all merchandise trade, 65% were agricultural commodities.

Understanding whether carbon leakage will occur or not is a complex task. Here, we look at what evidence we have and insights from agricultural trade modelling.

New Zealand modelling

It’s difficult to know exactly what might happen in agriculture, as emissions pricing on agricultural products has not yet been used elsewhere. There is no historical evidence to draw on.

International modelling studies present a mixed picture of the likelihood of leakage: an OECD study estimated 34% of agricultural emissions would be leaked, mostly to developing countries.

Recent modelling for New Zealand examines a series of scenarios of domestic pricing on its own as well as international pricing. The results show that for the current proposal where only 5% of emissions are priced to begin with, with a 1% increase each year, New Zealand’s production of meat and dairy products could decline by 2050.

The effect on dairy producers would be a loss of returns of under 1%, while meat producers would face a 6% decline. Some of the production would be taken up by other countries, but the overall volume would be lower than in the baseline situation, where no emissions pricing existed.

This graph shows the displacement of global dairy production in 2050, resulting from a levy on 5% of emissions from 2025, and increasing by 1% annually.
This graph shows the displacement of global dairy production in 2050, resulting from a levy on 5% of emissions from 2025, and increasing by 1% annually. Author provided, CC BY-ND

This shows leakage may occur, with reductions in production of New Zealand dairy products. But global meat and dairy production by 2050 would be considerably lower than without the policy, which would have a positive overall impact on the climate.

As the proportion of emissions that are priced increases, we expect the quantity of meat and dairy produced in New Zealand to decrease. This in turn could increase the volume of leakage. –

More sustainable future diets

It is important to remember that although there is a reduction in meat and dairy production, there is likely to be an increase in the production of other types of food which doesn’t contribute so much to climate change.

A recent study shows how food consumption alone could contribute an additional degree of warming above preindustrial temperatures by 2100. This demonstrates the importance of food choices in addressing climate change.

Many of New Zealand’s trading partners are exploring and beginning to implement their own agricultural emissions-reduction goals and targets. Internationally, there is an increasing focus on the role international trade rules can play in addressing climate change, including border carbon adjustment mechanisms and environmental standards for imports.

In a similar scenario as described above, but where New Zealand’s main competitors also take action, New Zealand may actually see a small increase in production by 2050, despite the domestic pricing policy.

The extent of leakage therefore really depends on how other countries tackle their own emissions. Economy-wide net zero emissions targets are in place for Australia, Chile, European Union countries, the US and the UK by 2050, and for China by 2060.

The opportunity for leakage would be significantly reduced through multilateral agreements or through regional or bilateral commitments within trade agreements.

New Zealand could decide to be a leader and demonstrate to the rest of the world a commitment to reducing emissions from our highest emitting sector. This may result in some leakage initially, but this would likely decline as other countries take similar action.

Or we can wait until other countries begin to take more serious action on agricultural emissions. But in the meantime, emissions reductions will increasingly be driven through finance and private-sector initiatives, for example through access to processing companies, which are progressively requiring emissions reductions throughout their value chains and through lending and finance, where banks are beginning to offer reduced interest rates for sustainable practices.The Conversation

, , , , , , , , ,

By: Matthew England, Scientia Professor and Deputy Director of the ARC Australian Centre for Excellence in Antarctic Science (ACEAS), UNSW Sydney; Adele Morrison Research Fellow, Australian National University; Andy Hogg Professor, Australian National University; Qian Li Massachusetts Institute of Technology (MIT); Steve Rintoul CSIRO Fellow, CSIRO.

 Republished in full from The Conversation under a Creative Commons license. See the original article: March 3, 2023

Off the coast of Antarctica, trillions of tonnes of cold salty water sink to great depths. As the water sinks, it drives the deepest flows of the “overturning” circulation – a network of strong currents spanning the world’s oceans. The overturning circulation carries heat, carbon, oxygen and nutrients around the globe, and fundamentally influences climate, sea level and the productivity of marine ecosystems.

But there are worrying signs these currents are slowing down. They may even collapse. If this happens, it would deprive the deep ocean of oxygen, limit the return of nutrients back to the sea surface, and potentially cause further melt back of ice as water near the ice shelves warms in response. There would be major global ramifications for ocean ecosystems, climate, and sea-level rise.

Conveyer overturning schematic showing the pathways of flow in the upper, deep and bottom layers of the ocean.

Our new research, published today in the journal Nature, uses new ocean model projections to look at changes in the deep ocean out to the year 2050. Our projections show a slowing of the Antarctic overturning circulation and deep ocean warming over the next few decades. Physical measurements confirm these changes are already well underway.

Climate change is to blame. As Antarctica melts, more freshwater flows into the oceans. This disrupts the sinking of cold, salty, oxygen-rich water to the bottom of the ocean. From there this water normally spreads northwards to ventilate the far reaches of the deep Indian, Pacific and Atlantic Oceans. But that could all come to an end soon. In our lifetimes.

The authors explain the results of their landmark paper: Is the Southern Ocean about to have its own ‘Day After Tomorrow’ moment? Fact-checked by experts, the video explains how these changes would profoundly alter the ocean’s overturning of heat, freshwater, oxygen, carbon and nutrients, with impacts felt throughout the global ocean for centuries to come.

Why does this matter?

As part of this overturning, about 250 trillion tonnes of icy cold Antarctic surface water sinks to the ocean abyss each year. The sinking near Antarctica is balanced by upwelling at other latitudes. The resulting overturning circulation carries oxygen to the deep ocean and eventually returns nutrients to the sea surface, where they are available to support marine life.

If the Antarctic overturning slows down, nutrient-rich seawater will build up on the seafloor, five kilometres below the surface. These nutrients will be lost to marine ecosystems at or near the surface, damaging fisheries.

Changes in the overturning circulation could also mean more heat gets to the ice, particularly around West Antarctica, the area with the greatest rate of ice mass loss over the past few decades. This would accelerate global sea-level rise.

An overturning slowdown would also reduce the ocean’s ability to take up carbon dioxide, leaving more greenhouse gas emissions in the atmosphere. And more greenhouse gases means more warming, making matters worse.

Meltwater-induced weakening of the Antarctic overturning circulation could also shift tropical rainfall bands around a thousand kilometres to the north.

Put simply, a slowing or collapse of the overturning circulation would change our climate and marine environment in profound and potentially irreversible ways.

Signs of worrying change

The remote reaches of the oceans that surround Antarctica are some of the toughest regions to plan and undertake field campaigns. Voyages are long, weather can be brutal, and sea ice limits access for much of the year.

This means there are few measurements to track how the Antarctic margin is changing. But where sufficient data exist, we can see clear signs of increased transport of warm waters toward Antarctica, which in turn causes ice melt at key locations.

Indeed, the signs of melting around the edges of Antarctica are very clear, with increasingly large volumes of freshwater flowing into the ocean and making nearby waters less salty and therefore less dense. And that’s all that’s needed to slow the overturning circulation. Denser water sinks, lighter water does not.

How did we find this out?

Apart from sparse measurements, incomplete models have limited our understanding of ocean circulation around Antarctica.

For example, the latest set of global coupled model projections analysed by the Intergovernmental Panel on Climate Change exhibit biases in the region. This limits the ability of these models in projecting the future fate of the Antarctic overturning circulation.

To explore future changes, we took a high resolution global ocean model that realistically represents the formation and sinking of dense water near Antarctica.

We ran three different experiments, one where conditions remained unchanged from the 1990s; a second forced by projected changes in temperature and wind; and a third run also including projected changes in meltwater from Antarctica and Greenland.

In this way we could separate the effects of changes in winds and warming, from changes due to ice melt.

The findings were striking. The model projects the overturning circulation around Antarctica will slow by more than 40% over the next three decades, driven almost entirely by pulses of meltwater.

Abyssal ocean warming driven by Antarctic overturning slowdown, Credit: Matthew England and Qian Li.

Over the same period, our modelling also predicts a 20% weakening of the famous North Atlantic overturning circulation which keeps Europe’s climate mild. Both changes would dramatically reduce the renewal and overturning of the ocean interior.

We’ve long known the North Atlantic overturning currents are vulnerable, with observations suggesting a slowdown is already well underway, and projections of a tipping point coming soon. Our results suggest Antarctica looks poised to match its northern hemisphere counterpart – and then some.

What next?

Much of the abyssal ocean has warmed in recent decades, with the most rapid trends detected near Antarctica, in a pattern very similar to our model simulations.

Our projections extend out only to 2050. Beyond 2050, in the absence of strong emissions reductions, the climate will continue to warm and the ice sheets will continue to melt. If so, we anticipate the Southern Ocean overturning will continue to slow to the end of the century and beyond.

The projected slowdown of Antarctic overturning is a direct response to input of freshwater from melting ice. Meltwater flows are directly linked to how much the planet warms, which in turn depends on the greenhouse gases we emit.

Our study shows continuing ice melt will not only raise sea-levels, but also change the massive overturning circulation currents which can drive further ice melt and hence more sea level rise, and damage climate and ecosystems worldwide. It’s yet another reason to address the
climate crisis – and fast.

wildfire

, , , , , , , , , , , , , , , , , ,

By: Professor of Energy and Climate Change, University of Manchester. Republished in full from The Conversation under a Creative Commons license. See the original article: March 25, 2023

The Intergovernmental Panel on Climate Change’s (IPCC) synthesis report recently landed with an authoritative thump, giving voice to hundreds of scientists endeavouring to understand the unfolding calamity of global heating. What’s changed since the last one in 2014? Well, we’ve dumped an additional third of a trillion tonnes of CO₂ into the atmosphere, primarily from burning fossil fuels. While world leaders promised to cut global emissions, they have presided over a 5% rise.

The new report evokes a mild sense of urgency, calling on governments to mobilise finance to accelerate the uptake of green technology. But its conclusions are far removed from a direct interpretation of the IPCC’s own carbon budgets (the total amount of CO₂ scientists estimate can be put into the atmosphere for a given temperature rise).

The report claims that, to maintain a 50:50 chance of warming not exceeding 1.5°C above pre-industrial levels, CO₂ emissions must be cut to “net-zero” by the “early 2050s”. Yet, updating the IPCC’s estimate of the 1.5°C carbon budget, from 2020 to 2023, and then drawing a straight line down from today’s total emissions to the point where all carbon emissions must cease, and without exceeding this budget, gives a zero CO₂ date of 2040.

Graph with lines
 A full description of the above chart is available here.
 
If emissions stay at their current levels, we will exhaust the 50% chance of 1.5°C in 9 years. If we begin to immediately cut emissions following the blue line, then to stay within the carbon budget for 50:50 chance of not exceeding 1.5°C we need zero global emissions by 2040. The vertical axis represents how much carbon is emitted each year – note the pandemic-related blip in 2020.
 

Given it will take a few years to organise the necessary political structures and technical deployment, the date for eliminating all CO₂ emissions to remain within 1.5°C of warming comes closer still, to around the mid-2030s. This is a strikingly different level of urgency to that evoked by the IPCC’s “early 2050s”. Similar smoke and mirrors lie behind the “early 2070s” timeline the IPCC conjures for limiting global heating to 2°C.

IPCC science embeds colonial attitudes

For over two decades, the IPCC’s work on cutting emissions (what experts call “mitigation”) has been dominated by a particular group of modellers who use huge computer models to simulate what may happen to emissions under different assumptions, primarily related to price and technology. I’ve raised concerns before about how this select cadre, almost entirely based in wealthy, high-emitting nations, has undermined the necessary scale of emission reductions.

In 2023, I can no longer tiptoe around the sensibilities of those overseeing this bias. In my view, they have been as damaging to the agenda of cutting emissions as Exxon was in misleading the public about climate science. The IPCC’s mitigation report in 2022 did include a chapter on “demand, services and social aspects” as a repository for alternative voices, but these were reduced to an inaudible whisper in the latest report’s influential summary for policymakers.

The specialist modelling groups (referred to as Integrated Assessment Modelling, or IAMs) have successfully crowded out competing voices, reducing the task of mitigation to price-induced shifts in technology – some of the most important of which, like so-called “negative emissions technologies”, are barely out of the laboratory.

The IPCC offers many “scenarios” of future low-carbon energy systems and how we might get there from here. But as the work of academic Tejal Kanitkar and others has made clear, not only do these scenarios prefer speculative technology tomorrow over deeply challenging policies today (effectively a greenwashed business-as-usual), they also systematically embed colonial attitudes towards “developing nations”.

With few if any exceptions, they maintain current levels of inequality between developed and developing nations, with several scenarios actually increasing the levels of inequality. Granted, many IAM modellers strive to work objectively, but they do so within deeply subjective boundaries established and preserved by those leading such groups.

Four people in formal attire converse on a stage behind a
March 2023’s synthesis report capped eight years of research. IISD/ENB/Anastasia Rodopoulou

 

What happened to equity?

If we step outside the rarefied realm of IAM scenarios that leading climate scientist Johan Rockström describes as “academic gymnastics that have nothing to do with reality”, it’s clear that not exceeding 1.5°C or 2°C will require fundamental changes to most facets of modern life.

Starting now, to not exceed 1.5°C of warming requires 11% year-on-year cuts in emissions, falling to nearer 5% for 2°C. However, these global average rates ignore the core concept of equity, central to all UN climate negotiations, which gives “developing country parties” a little longer to decarbonise.

Include equity and most “developed” nations need to reach zero CO₂ emissions between 2030 and 2035, with developing nations following suit up to a decade later. Any delay will shrink these timelines still further.

Most IAM models ignore and often even exacerbate the obscene inequality in energy use and emissions, both within nations and between individuals. As the International Energy Agency recently reported, the top 10% of emitters accounted for nearly half of global CO₂ emissions from energy use in 2021, compared with 0.2% for the bottom 10%. More disturbingly, the greenhouse gas emissions of the top 1% are 1.5 times those of the bottom half of the world’s population.

So where does this leave us? In wealthier nations, any hope of arresting global heating at 1.5 or 2°C demands a technical revolution on the scale of the post-war Marshall Plan. Rather than relying on technologies such as direct air capture of CO₂ to mature in the near future, countries like the UK must rapidly deploy tried-and-tested technologies.

Retrofit housing stock, shift from mass ownership of combustion-engine cars to expanded zero-carbon public transport, electrify industries, build new homes to Passivhaus standard, roll-out a zero-carbon energy supply and, crucially, phase out fossil fuel production.

Three decades of complacency has meant technology on its own cannot now cut emissions fast enough. A second, accompanying phase, must be the rapid reduction of energy and material consumption.

Given deep inequalities, this, and deploying zero-carbon infrastructure, is only possible by re-allocating society’s productive capacity away from enabling the private luxury of a few and austerity for everyone else, and towards wider public prosperity and private sufficiency.

For most people, tackling climate change will bring multiple benefits, from affordable housing to secure employment. But for those few of us who have disproportionately benefited from the status quo, it means a profound reduction in how much energy we use and stuff we accumulate.

The question now is, will we high-consuming few make (voluntarily or by force) the fundamental changes needed for decarbonisation in a timely and organised manner? Or will we fight to maintain our privileges and let the rapidly changing climate do it, chaotically and brutally, for us?

Load More