Welcome to Carbon Brief’s DeBriefed.
An essential guide to the week’s key developments relating to climate change.
This week
Eyes on the Arctic
SOURCE, NOT SINK: The Arctic tundra has become a net emitter of greenhouse gases, rather than a “carbon sink”, for the first time, according to the Arctic Report Card issued this week by the US National Oceanic and Atmospheric Administration. The Alaska Beacon wrote that this shift is “result of permafrost warming, increased wildfires and other effects of climate change”.
ARCTIC ACREAGE: E&E News reported that the US Bureau of Land Management will open 400,000 acres of the Arctic National Wildlife Refuge for oil and gas drilling, despite promises to the contrary during Joe Biden’s 2020 campaign. The area represents the minimum that was required to be put up for sale by Donald Trump’s 2017 tax bill, which opened the preserve to development, Reuters said.
UK’s path to ‘clean power’
ACTION PLAN: The UK government published a 136-page “action plan” for reaching its goal for low-carbon sources to meet 100% of electricity demand and 95% of generation by 2030, BBC News reported. It includes various reforms that ministers will introduce over 2025 to boost renewables, change the planning system, increase flexibility in the electricity grid and support energy storage projects, according to the broadcaster.
RECORD RENEWABLES: The Financial Times said that the government is considering weakening the rights of communities to object to new pylons or windfarms in their neighbourhoods as part of the plans. It added that, in a bid to meet its goals, the government is “preparing a record-breaking auction of renewable subsidy contracts next year”. Carbon Brief has just published an in-depth run down of the plan’s key details.
Around the world
- BRONZE MEDAL HEAT: The UK Met Office has predicted that 2025 will likely be in the top three warmest years on record, “falling in line just behind 2024 and 2023”.
- CANADA TARGET: Canada has a new target to cut its emissions to 45-50% below 2005 levels by 2035, a less ambitious pledge than its climate advisers suggested, Climate Home News reported. A statement from Canada said the pledge will be submitted to the UN in 2025 and act as its “nationally determined contribution” (NDC) under the Paris Agreement.
- HIGHLY DRY: More than three-quarters of Earth’s land is “permanently drying”, according to a report released at the UN desertification summit in Riyadh. AfricaNews reported that nearly five billion people will be affected by drying by the end of the century, if current warming trends continue.
- DENGUE ON THE RISE: The Pan-American Health Organization announced that, this year, the Americas have “faced the largest dengue epidemic since records began” more than 40 years ago. It said “the situation is linked to climate events favouring mosquito proliferation”.
- ‘NO WINNERS’: “Tariff wars, trade wars and sci-tech wars” will have “no winners”, Chinese president Xi Jinping said in a recent meeting with representatives from “major international economic organisations”, according to Xinhua.
- GEOENGINEERING GUIDANCE: The EU’s scientific advisory group recommended that the bloc should move to “prohibit solar geoengineering technologies…and push for a worldwide ban”, Politico reported.
£57.5 million
The record amount of funding provided to farmers in England who were impacted by last winter’s severe flooding, according to figures released to Carbon Brief.
Latest climate research
- According to research in Science, the 2014-16 marine heatwave in the Pacific Ocean killed at least half of Alaska’s common murre, an abundant seabird species.
- Climate-change-driven shifts in atmospheric circulation will result in increased turbulence over Europe, especially during the winter months, a study in Geophysical Research Letters found.
- A rapid attribution analysis by the World Weather Attribution service found that this year’s record-setting typhoon season that battered the Philippines was “supercharged” by climate change. Carbon Brief covered the findings.
(For more, see Carbon Brief’s in-depth daily summaries of the top climate news stories on Monday, Tuesday, Wednesday, Thursday and Friday.)
Captured
Ahead of Donald Trump’s second term as US president, a rerun of his first trade war with China is firmly on the cards – and minerals key to the energy transition may end up in the crossfire. Carbon Brief took an in-depth look at what US-China tensions over critical minerals could mean for the stability of their supply chains and for the transition to cleaner energy. The Venn diagram above – put together by the Chinese government and translated to English by Carbon Brief – shows where China expects there to be overlap between itself, the EU and the US when it comes to minerals and materials considered to be “critical” for energy and industry.
Spotlight
What concerns climate scientists
This week, Carbon Brief speaks to scientists at the annual meeting of the American Geophysical Union in Washington DC about what is on their minds as 2024 draws to a close, and what they think the biggest climate stories of 2025 might be.
Their answers have been lightly edited for length and clarity.
Prof David Ho, professor of oceanography at the University of Hawaii at Manoa and co-founder and chief science officer at [c]worthy
All I seem to think about these days is CDR – carbon dioxide removal. Normally I say that it doesn’t make sense to deploy [CDR] until we decarbonise drastically, because it is useless when we’re still emitting more than 40bn tonnes of CO2 every year…But if we don’t start now, we might not be able to scale [up] fast enough.
I’m thinking about that because it does have to go from something that most people have never heard of, to the biggest thing we’ve ever done, in a short time.
It’s really hard to know with the new administration in the US [what the biggest story will be].
But the overarching story, of course, is that we’re emitting more CO2 – things are getting worse, and we’re not doing anything about it. And whether that remains the biggest story or not, I don’t know, because it seems like everything that we do is small compared to the fact that we don’t do anything about the continued use of fossil fuels.
Dr Sahra Kacimi, a polar scientist at the NASA Jet Propulsion Laboratory
There are a couple things that have been on my mind. My research is really focused on sea ice and how can we better monitor it from space, which means providing better estimates of sea ice thickness, including the snow on top of it, and then trying to use a combination of satellite observations to really better understand the state of sea ice and how it’s changing in the context of global warming.
I’m really interested in this new satellite mission called SWOT [Surface Water and Ocean Topography]. To me, it really marks the beginning of a new era…Everyone you can talk to – people working on hydrology, oceanography, sea ice – what we’re seeing is just incredible.
Antarctic sea ice is a really hot topic, because there’s still a lot of things that we don’t know about it and about why it’s been changing so much in the past few years…Not necessarily next year, but in the next few years, the Southern Ocean and Antarctic sea ice and Antarctic climate is going to be a major, major climate story.
Dr Cynthia Rosenzweig, senior research scientist and head of the Climate Impacts Group at the NASA Goddard Institute for Space Studies and winner of the 2022 World Food Prize
When AgMIP [the Agricultural Model Intercomparison and Improvement Project] started and we started holding these sessions at AGU on the effects of climate change on agriculture and food, they would be very small. And now you can see how this area is growing in importance and [in] the science.
The work is going beyond the “big four” crops – wheat, rice, maize and soya beans. Of course they will always be very important, but you can see a role for a much broader range of crops…I would also say [there’s a growing focus on] mitigation and adaptation together.
It’s wonderful to see all this wonderful work. But unless you coordinate it and actually then bring it to the policymakers, where does it go? And so that’s really the meaning of AgMIP. [We’re holding] the 10th global workshop in March-April. We’ll be bringing together teams of people who actually do the work, and they work together at the workshop. I really believe in putting “work” back in workshops.
Dr Erich Fischer, a climate scientist and lecturer at ETH Zürich
We have now seen the first year with 1.5C of global temperature rise, but that’s just the first one. So most places haven’t yet seen anything close to the highest local temperature, precipitation or drought conditions possible under today’s climate – even without any further warming. I expect to see a lot more records being broken in 2025.
And then the big question is whether global temperatures will continue to rise at these rates. This has implications for all regions of the globe – including the oceans, which are warming very rapidly themselves.
Watch, read, listen
SURVIVAL STORY?: The Washington Post’s Post Reports podcast asked whether the Inflation Reduction Act can survive the term of incoming president Donald Trump.
WORKING THE NIGHT SHIFT: Grist examined how fisherfolk and farmworkers are adjusting to overnight shifts to escape extreme daytime temperatures.
(RE)WILD THING: A comic in Vox explained how rewilding your lawn can help boost biodiversity and contribute to mitigating climate change.
Coming up
- 9-16 December: Plenary session of the Intergovernmental Science-Policy Platform for Biodiversity and Ecosystem Services (IPBES), Windhoek, Namibia
- 16-20 December: 68th meeting of the Global Environment Facility Council, Online
- 17 December: Launch of IPBES nexus assessment
- 17 December: 168th meeting of the committee of permanent representatives of the UN Environment Programme, Nairobi, Kenya
- 18 December: Launch of IPBES transformative change assessment
Pick of the jobs
- International Centre for Integrated Mountain Development, Living Mountain Lab outreach specialist | Salary: $33,720. Location: Kathmandu, Nepal
- Sustainability Research Group at the University of Basel, funded PhD in sustainable agri-food system governance (two roles) | Salary: Unknown. Location: Basel, Switzerland
- Wired, senior writer, climate | Salary: $95,000-$127,000. Location: San Francisco, New York, London or remote
DeBriefed is edited by Daisy Dunne. Please send any tips or feedback to debriefed@carbonbrief.org.
This is an online version of Carbon Brief’s weekly DeBriefed email newsletter. Subscribe for free here.
The post DeBriefed 13 December 2024: Arctic tundra emitting CO2; UK sets path to ‘clean power’; What climate scientists worry about appeared first on Carbon Brief.
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 Rus