Countries that pump out large amounts of greenhouse gases could “retain or expand” their fossil fuel industries while treating such emissions as “inevitable” in their net-zero accounting, according to a new study.
Some sectors, such as livestock farming and heavy industry, are viewed as particularly hard to decarbonise. This is due, in part, to a perceived lack of cheap technological solutions.
Any “residual emissions” from these practices will have to be balanced by removals from the atmosphere, if nations want to claim they have achieved their net-zero goals.
The new study, published in One Earth, analyses the strategies that nations have submitted to the UN to understand their approach to these emissions, and how they define them.
It finds significant uncertainty, with just 26 out of 71 countries with long-term plans having outlined how much they expect to still be emitting by 2050.
These nations alone say their residual emissions could be up to 2.9bn tonnes of carbon dioxide equivalent (GtCO2e) – equivalent to around 5% of the current global total.
Fossil-fuel producing nations, such as Australia and Canada, plan to continue producing large volumes of emissions – before removing them via carbon capture technologies or paying for them to be offset elsewhere.
The study authors warn that the slow development and rollout of CO2 removal technologies means this approach could lead to net-zero ambitions ending in “failure”.
Hard-to-abate?
“Residual” emissions are defined as those that remain once a nation, or some other entity, has gone as far as it thinks is possible to cut greenhouse gas emissions.
The concept is closely tied with the net-zero targets that many nations have set for the middle of the century. A country must remove CO2 from the atmosphere that is equivalent in volume to its residual emissions, in order to say it has reached net-zero.
The amount of residual emissions each country is left with therefore dictates how much it will have to invest in CO2 removal – either by planting trees or building machines that directly remove the CO2 from the atmosphere.
So far, countries have shown very little progress in developing technologies to remove CO2.
Yet, as the new study explains, “there is a tendency to treat residual emissions as inevitable”. One key reason for this is that these emissions are expected to largely come from so-called “hard-to-abate” sectors.
These sectors are generally framed as those that lack cheap and widely available technologies to drastically cut their emissions. Examples include steel production, aviation and many aspects of livestock agriculture, such as rearing cows, growing rice and using fertilisers..
Yet, despite these common framings, in practice, both residual emissions and hard-to-abate sectors remain poorly defined. Moreover, there is a growing body of evidence suggesting that even “hard-to-abate” sectors can feasibly be decarbonised using available technologies.
According to Prof Naomi Vaughan, a climate change researcher at the University of East Anglia (UEA) and one of the new study’s co-authors, this means “net-zero can hide a multitude of sins”. Speaking to Carbon Brief, she asks:
“What are you choosing – as an industry or as a country – to decide is hard to abate…And what genuinely is?”
In order to interrogate this, the team led by Harry Smith, a UEA PhD student focusing on the role of CO2 removal in climate policy, set out to understand what different countries were describing as “residual emissions” and how they were justifying this description.
Big residuals
Under the Paris Agreement, nations are encouraged to submit long-term low-emission development strategies (LT-LEDS). If a country has a mid-century net-zero target, this document will explain how it intends to get there.
In their study, Smith and his colleagues analyse every LT-LEDS submitted to the UN by October 2023 – covering a total of 67 countries. They also include four extra long-term strategies produced by EU member states, but not submitted to the UN.
The 71 nations with long-term strategies for tackling climate change cover 71% of global emissions, the study notes.
However, the majority – 41 in total – do not quantify residual emissions at all in their plans. These include major emitters with net-zero targets, such as China, India and Russia.
The researchers identify 26 countries that have calculated the amount of emissions they expect to still be producing at the point they reach net-zero.
In total, this amounts to between 2.6-2.9GtCO2e, excluding emissions from land use, land-use change and forestry (LULUCF). (The range results from countries including several different scenarios in their strategies.)
The study also compares the scale of each nation’s residual emissions to the highest level its emissions have reached in a year. If countries are yet to peak, data from 2021 was used.
The authors conclude that, on average, the 16 developed “Annex I” countries assessed in this study plan on still producing 21% of their peak emissions when they reach net-zero.
Meanwhile, the nine developing and emerging “Annex II” economies expect to continue producing 34% of their peak emissions, the study finds. This estimate excludes Cambodia, which plans to keep increasing its emissions but cancelling them out by turning its extensive forests into a net carbon sink.
The chart below shows residual emissions (red) as a share of each nation’s peak emissions (blue) – or its most recent annual emissions, if its emissions have not yet peaked. Residual emissions from the US alone are set to be higher than the total emissions of nearly every other country.
Justifying emissions
To understand more about how governments justify the residual emissions in their strategies, the researchers analyse the sectors where emissions remain high out into the second half of this century.
Overall, agriculture is expected to see the least progress in emissions reductions, contributing roughly one-third of residual emissions across all the nations assessed, the study finds.
Methane from livestock and emissions from fertilisers are frequently cited as some of the “hardest-to-abate”. Developed countries only expect their agricultural emissions to drop 37%, on average, by the time they hit net-zero.
(International aviation and shipping, while viewed as some of the hardest sectors to decarbonise, are simply excluded from most countries’ long-term plans, meaning they do not feature prominently in this analysis.)
The researchers also look in greater depth at the rationales given by each country for defining emissions as “residual” or “hard-to-abate”, by analysing 357 statements on the topic within the long-term strategies. They group the statements into different categories, based on which sectors are described and the type of language used.
As the chart below shows, countries frequently provide no justification at all for their continued production of residual emissions in particular sectors.
The definition of “residual” varies considerably between countries, with governments focusing on different aspects depending on their circumstances. Smith tells Carbon Brief:
“What you find is this range of rationales [that are] not just technical…They’re not just political either…It’s a kind of pick your buffet of rationales.”
The most common arguments concern residual emissions from industry and transport – particularly the production of cement and steel, the emissions of F-gases and domestic aviation and shipping. (The researchers note a “mismatch” here, with arguments explaining residual emissions from agriculture often overlooked, despite it being the largest contributor.)
Countries most frequently cite the lack of new technologies and limits to existing ones as the reasons for continued emissions from these sectors.
Despite these assertions, hundreds of industry leaders from the heavy industry and heavy-duty transport sectors have described net-zero goals as “technically and financially possible by mid-century”.
For example, a recent report by the International Renewable Energy Agency (IRENA) concluded that “the technologies to decarbonise hard-to-abate sectors have seen significant progress in recent years and are today largely available”.
‘Retain or expand’
The large amounts of residual emissions in most nations’ long-term strategies reveals that many are expecting to lean heavily on carbon removal to meet their net-zero targets, the study says.
The study notes that this “risks the credibility of their target[s] and risks a failure to meet national and global net-zero”, given the known limits to carbon removals.
In some cases, this could also mean shifting responsibility elsewhere by purchasing carbon offsets from other countries.
Moreover, the study adds that some nations “may attempt to retain or expand their fossil fuel production”, and pass off resulting emissions as “residual”. Vaughan explains that countries may lean towards looser definitions of residual emissions, if it benefits them:
“If you have a country with a very significant investment in the fossil fuel industry or extraction industries, then there is an incentive to imagine getting to net-zero where you still have quite a lot of emissions – but you’re using lot’s of CO2 removal to get there.”
The authors highlight Australia and Canada, two nations that currently produce large amounts of fossil fuels. Both include scenarios in their net-zero strategies – albeit at the high end of several potential outcomes – where emissions only fall by around half by 2050.
In Australia’s case, this scenario relies on purchasing large amounts of carbon offsets from other countries. Canada relies on very high use of CO2 removal technologies.
Prof Holly Jean Buck, a climate researcher at the University of Buffalo who published an initial investigation into residual emissions in countries’ LT-LEDS last year, but was not involved in this research. She says tackling the “ambiguity” around these emissions is key:
“We don’t know if countries are planning to phase out fossil fuels…We have infrastructure that has long lifetimes in terms of how long it takes to build it and how long it will be in operation. Without specificity around which sectors or activities we hope to fully decarbonise and electricity, it’s hard for countries to do that planning.”
More political
Experts tell Carbon Brief the new study is a welcome contribution to a relatively sparse literature on residual emissions.
Buck says it is a “thorough and careful” study that expands on her work, both by increasing the number of strategies assessed and broadening the scope of the analysis.
Her assessment only focused on high-ambition strategies for LT-LEDS from Annex I countries. The new research led by Smith and his colleagues includes a broader range of scenarios, and suggests that residual emissions could be even higher in 2050 than thought.
The study proposes a number of measures to tighten the definition of “residual” emissions and help countries better address them. This includes stronger reporting requirements for national strategies.
The researchers also propose separate targets for emissions reductions and CO2 removals, in order to prevent countries continuing to burn fossil fuels while simply pledging to remove emissions.
Dr William Lamb, a researcher at the Mercator Research Institute on Global Commons and Climate Change who was not involved in the study, tells Carbon Brief he supports this idea and adds:
“I would also like to see the discussion of residual emissions become more political than it currently is. If countries were asking questions such as ‘how fast can we phase out fossil fuels?’ and ‘what human needs and services do we need to deliver, at minimum impact to the climate?’ then their long-term strategies would look very different.”
The post Major emitters ‘may retain or expand’ fossil fuels despite net-zero plans appeared first on Carbon Brief.
Major emitters ‘may retain or expand’ fossil fuels despite net-zero plans
Drought and heatwaves occurring together – known as “compound” events – have “surged” across the world since the early 2000s, a new study shows.
Compound drought and heat events (CDHEs) can have devastating effects, creating the ideal conditions for intense wildfires, such as Australia’s “Black Summer” of 2019-20 where bushfires burned 24m hectares and killed 33 people.
The research, published in Science Advances, finds that the increase in CDHEs is predominantly being driven by events that start with a heatwave.
The global area affected by such “heatwave-led” compound events has more than doubled between 1980-2001 and 2002-23, the study says.
The rapid increase in these events over the last 23 years cannot be explained solely by global warming, the authors note.
Since the late 1990s, feedbacks between the land and the atmosphere have become stronger, making heatwaves more likely to trigger drought conditions, they explain.
One of the study authors tells Carbon Brief that societies must pay greater attention to compound events, which can “cause severe impacts on ecosystems, agriculture and society”.
Compound events
CDHEs are extreme weather events where drought and heatwave conditions occur simultaneously – or shortly after each other – in the same region.
These events are often triggered by large-scale weather patterns, such as “blocking” highs, which can produce “prolonged” hot and dry conditions, according to the study.
Prof Sang-Wook Yeh is one of the study authors and a professor at the Ewha Womans University in South Korea. He tells Carbon Brief:
“When heatwaves and droughts occur together, the two hazards reinforce each other through land-atmosphere interactions. This amplifies surface heating and soil moisture deficits, making compound events more intense and damaging than single hazards.”
CDHEs can begin with either a heatwave or a drought.
The sequence of these extremes is important, the study says, as they have different drivers and impacts.
For example, in a CDHE where the heatwave was the precursor, increased direct sunshine causes more moisture loss from soils and plants, leading to a drought.
Conversely, in an event where the drought was the precursor, the lack of soil moisture means that less of the sun’s energy goes into evaporation and more goes into warming the Earth’s surface. This produces favourable conditions for heatwaves.
The study shows that the majority of CDHEs globally start out as a drought.
In recent years, there has been increasing focus on these events due to the devastating impact they have on agriculture, ecosystems and public health.
In Russia in the summer of 2010, a compound drought-heatwave event – and the associated wildfires – caused the death of nearly 55,000 people, the study notes.
The record-breaking Pacific north-west “heat dome” in 2021 triggered extreme drought conditions that caused “significant declines” in wheat yields, as well as in barley, canola and fruit production in British Columbia and Alberta, Canada, says the study.
Increasing events
To assess how CDHEs are changing, the researchers use daily reanalysis data to identify droughts and heatwaves events. (Reanalysis data combines past observations with climate models to create a historical climate record.) Then, using an algorithm, they analyse how these events overlap in both time and space.
The study covers the period from 1980 to 2023 and the world’s land surface, excluding polar regions where CDHEs are rare.
The research finds that the area of land affected by CDHEs has “increased substantially” since the early 2000s.
Heatwave-led events have been the main contributor to this increase, the study says, with their spatial extent rising 110% between 1980-2001 and 2002-23, compared to a 59% increase for drought-led events.
The map below shows the global distribution of CDHEs over 1980-2023. The charts show the percentage of the land surface affected by a heatwave-led CDHE (red) or a drought-led CDHE (yellow) in a given year (left) and relative increase in each CDHE type (right).
The study finds that CDHEs have occurred most frequently in northern South America, the southern US, eastern Europe, central Africa and south Asia.
Threshold passed
The authors explain that the increase in heatwave-led CDHEs is related to rising global temperatures, but that this does not tell the whole story.
In the earlier 22-year period of 1980-2001, the study finds that the spatial extent of heatwave-led CDHEs rises by 1.6% per 1C of global temperature rise. For the more-recent period of 2022-23, this increases “nearly eightfold” to 13.1%.
The change suggests that the rapid increase in the heatwave-led CDHEs occurred after the global average temperature “surpasse[d] a certain temperature threshold”, the paper says.
This threshold is an absolute global average temperature of 14.3C, the authors estimate (based on an 11-year average), which the world passed around the year 2000.
Investigating the recent surge in heatwave-leading CDHEs further, the researchers find a “regime shift” in land-atmosphere dynamics “toward a persistently intensified state after the late 1990s”.
In other words, the way that drier soils drive higher surface temperatures, and vice versa, is becoming stronger, resulting in more heatwave-led compound events.
Daily data
The research has some advantages over other previous studies, Yeh says. For instance, the new work uses daily estimations of CDHEs, compared to monthly data used in past research. This is “important for capturing the detailed occurrence” of these events, says Yeh.
He adds that another advantage of their study is that it distinguishes the sequence of droughts and heatwaves, which allows them to “better understand the differences” in the characteristics of CDHEs.
Dr Meryem Tanarhte is a climate scientist at the University Hassan II in Morocco, and Dr Ruth Cerezo Mota is a climatologist and a researcher at the National Autonomous University of Mexico. Both scientists, who were not involved in the study, agree that the daily estimations give a clearer picture of how CDHEs are changing.
Cerezo-Mota adds that another major contribution of the study is its global focus. She tells Carbon Brief that in some regions, such as Mexico and Africa, there is a lack of studies on CDHEs:
“Not because the events do not occur, but perhaps because [these regions] do not have all the data or the expertise to do so.”
However, she notes that the reanalysis data used by the study does have limitations with how it represents rainfall in some parts of the world.
Compound impacts
The study notes that if CDHEs continue to intensify – particularly events where heatwaves are the precursors – they could drive declining crop productivity, increased wildfire frequency and severe public health crises.
These impacts could be “much more rapid and severe as global warming continues”, Yeh tells Carbon Brief.
Tanarhte notes that these events can be forecasted up to 10 days ahead in many regions. Furthermore, she says, the strongest impacts can be prevented “through preparedness and adaptation”, including through “water management for agriculture, heatwave mitigation measures and wildfire mitigation”.
The study recommends reassessing current risk management strategies for these compound events. It also suggests incorporating the sequences of drought and heatwaves into compound event analysis frameworks “to enhance climate risk management”.
Cerezo-Mota says that it is clear that the world needs to be prepared for the increased occurrence of these events. She tells Carbon Brief:
“These [risk assessments and strategies] need to be carried out at the local level to understand the complexities of each region.”
The post Heatwaves driving recent ‘surge’ in compound drought and heat extremes appeared first on Carbon Brief.
Heatwaves driving recent ‘surge’ in compound drought and heat extremes
Greenhouse Gases
DeBriefed 6 March 2026: Iran energy crisis | China climate plan | Bristol’s ‘pioneering’ wind turbine
Welcome to Carbon Brief’s DeBriefed.
An essential guide to the week’s key developments relating to climate change.
This week
Energy crisis
ENERGY SPIKE: US-Israeli attacks on Iran and subsequent counterattacks across the Middle East have sent energy prices “soaring”, according to Reuters. The newswire reported that the region “accounts for just under a third of global oil production and almost a fifth of gas”. The Guardian noted that shipping traffic through the strait of Hormuz, which normally ferries 20% of the world’s oil, “all but ground to a halt”. The Financial Times reported that attacks by Iran on Middle East energy facilities – notably in Qatar – triggered the “biggest rise in gas prices since Russia’s full-scale invasion of Ukraine”.
‘RISK’ AND ‘BENEFITS’: Bloomberg reported on increases in diesel prices in Europe and the US, speculating that rising fuel costs could be “a risk for president Donald Trump”. US gas producers are “poised to benefit from the big disruption in global supply”, according to CNBC. Indian government sources told the Economic Times that Russia is prepared to “fulfil India’s energy demands”. China Daily quoted experts who said “China’s energy security remains fundamentally unshaken”, thanks to “emergency stockpiles and a wide array of import channels”.
‘ESSENTIAL’ RENEWABLES: Energy analysts said governments should cut their fossil-fuel reliance by investing in renewables, “rather than just seeking non-Gulf oil and gas suppliers”, reported Climate Home News. This message was echoed by UK business secretary Peter Kyle, who said “doubling down on renewables” was “essential” amid “regional instability”, according to the Daily Telegraph.
China’s climate plan
PEAK COAL?: China has set out its next “five-year plan” at the annual “two sessions” meeting of the National People’s Congress, including its climate strategy out to 2030, according to the Hong Kong-based South China Morning Post. The plan called for China to cut its carbon emissions per unit of gross domestic product (GDP) by 17% from 2026 to 2030, which “may allow for continued increase in emissions given the rate of GDP growth”, reported Reuters. The newswire added that the plan also had targets to reach peak coal in the next five years and replace 30m tonnes per year of coal with renewables.
ACTIVE YET PRUDENT: