A NIWA-led study has found New Zealand’s native forests are absorbing more carbon dioxide (CO2) than previously thought.
Study leader, NIWA atmospheric scientist Dr Beata Bukosa, says the findings could have implications for New Zealand’s greenhouse gas reporting, carbon credit costs, and climate and land-use policies.
She says forests – both native and exotic – play a vital role in absorbing CO₂ through photosynthesis, but previous studies may have underestimated the amount of carbon taken up by New Zealand’s mature indigenous forests, which were thought to be roughly carbon neutral.
Using advanced modelling and NIWA’s supercomputer, the researchers examined a decade of atmospheric data, from 2011 to 2020, to better estimate the amount of CO₂ absorbed by New Zealand’s land ecosystems. The NIWA team worked with collaborators at GNS Science and Manaaki Whenua as well as other New Zealand and overseas universities and institutes.
The team used an inverse modelling technique – this combines atmospheric greenhouse gases with a model showing how air is transported through the atmosphere to identify CO2 sources and sinks – and compared the results against New Zealand’s Greenhouse Gas Inventory as well as ‘bottom-up’ models. While the Inventory applies a combination of field inventory, modelling, and remote sensing to quantify forest carbon stocks and stock changes, the ‘bottom-up’ models use calculations based on ecosystem processes, land use and climate across the country, says Dr Bukosa.
“It was thought that some areas and land use types were in a near-balance state with the absorption and release of CO₂. Earlier estimates of how much carbon was removed by New Zealand land ecosystems ranged from a net 24 to 118 million tonnes a year. Our research found that New Zealand’s natural environment absorbed approximately 171 million tonnes of CO₂ annually.” – Dr Bukosa
She says the largest differences between earlier estimates and the new findings came in the South Island.
“This was especially in areas dominated by mature native forests and certain grazing lands. We also found seasonal variation, as during autumn and winter, less CO₂ is released into the atmosphere than earlier estimates suggested.”
“That study was based on only three years of data, and we weren’t sure
if it was just a transient effect related to the climatic conditions, or
if the effect was confined to Fiordland. Our new study shows the carbon
sink is more widespread than we thought, particularly across the South
Island, with greater uptake of CO₂ extending up the West Coast.
“With improvements in our modelling techniques, and data coverage, we’ve
now shown the extra carbon uptake has persisted for at least a decade.
More research could help us understand exactly why our method has shown
such a difference in the carbon source and sink balance compared with
other methods.”
Inverse modelling provides an independent estimate of emissions that can complement inventory-based approaches for emissions reporting, she says.
“New Zealand was the first country to develop the capability to infer
national CO₂ emissions from atmospheric data and has since supported
other countries to develop similar capability.”
Dr Andrea Brandon, a Ministry for the Environment principal scientist who co-authored the study, said the findings help build a clearer picture of the role New Zealand’s natural systems play in absorbing emissions from the atmosphere. However, further work will be needed before they can be included in official emissions reporting.
“We continually improve the Inventory – New
Zealand’s annual record of emissions and removals – as new science and
evidence comes to light. This ensures we have robust information so that
we continue to meet our international reporting obligations.
“The findings from this study indicate there
may be additional carbon uptake somewhere in the system that we are
currently not tracking. We need to identify what we are missing so that
we can further refine our Inventory methods to capture it,” – Dr Andrea Brandon
Dr Bukosa says the results, due to be published shortly in the journal Atmospheric Chemistry and Physics and available here in preprint, have important implications for New Zealand’s tracking of carbon emissions and climate policies:
“We need to better understand why our native forests are absorbing more
CO₂ than expected, and what this could mean for our efforts to reduce
greenhouse gas emissions and achieve our domestic and international
targets.”
The research was part of a NIWA-led, MBIE-funded Endeavour programme called CarbonWatch NZ, which ended last year. NIWA principal scientist Dr Sara Mikaloff-Fletcher led CarbonWatch NZ and says the team is now looking to extend this work to definitively solve the puzzle of the difference in carbon between inventory methods and atmospheric measurements.
“This research suggests that we could make the most of opportunities to
slow climate change through changes to land management. Projections
suggest New Zealand will need 84 million tonnes of emissions reductions
on top of what can be done at home to meet its 2030 international
commitments under the Paris Agreement. In addition to reducing the need
for overseas offsets, better management of our native forests and other
lands could enable New Zealand to be long-term stewards of our carbon
sinks and offer magnificent biodiversity co-benefits.” – Dr
Mikaloff-Fletcher
The 2015 Paris agreement committed countries to keeping the global temperature increase “well below 2°C”, which is widely interpreted as an average of 1.5°C over a 30-year period. The Paris agreement has not yet failed, but recent high temperatures show how close the Earth is to crossing this critical threshold.
Climate scientists have, using computer simulations, modelled pathways for halting climate change at internationally agreed limits. However, in recent years, many of the pathways that have been published involve exceeding 1.5°C for a few decades and removing enough greenhouse gas from the atmosphere to return Earth’s average temperature below the threshold again. Scientists call this “a temporary overshoot”.
If human activities were to raise the global average temperature 1.6°C above the pre-industrial average, for example, then CO₂ removal, using methods ranging from habitat restoration to mechanically capturing CO₂ from the air, would be required to return warming to below 1.5°C by 2100.
Do we really understand the consequences of “temporarily” overshooting 1.5°C? And would it even be possible to lower temperatures again?
Faith that a temporary overshoot will be safe and practicable has justified a deliberate strategy of delaying emission cuts in the short term, some scientists warn. The dangers posed by remaining above the 1.5°C limit for a period of time have received little attention by researchers like me, who study climate change.
To learn more, the UK government commissioned me and a team of 36 other scientists to examine the possible impacts.
How nature will be affected
We examined a “delayed action” scenario, in which greenhouse gas emissions remain similar for the next 15 years due to continued fossil fuel burning but then fall rapidly over a period of 20 years.
We projected that this would cause the rise in Earth’s temperature to peak at 1.9°C in 2060, before falling to 1.5°C in 2100 as greenhouse gases are removed from the atmosphere. We compared this scenario with a baseline scenario in which the global temperature does not exceed 1.5°C of warming this century.
Our Earth system model suggested that Arctic temperatures would be up to 4°C higher in 2060 compared to the baseline scenario. Arctic Sea ice loss would be much higher. Even after the global average temperature was returned to 1.5°C above pre-industrial levels, in 2100, the Arctic would remain around 1.5°C warmer compared to the baseline scenario. This suggests there are long-term and potentially irreversible consequences for the climate in overshooting 1.5°C.
As global warming approaches 2°C, warm-water corals, Arctic permafrost, Barents Sea ice and mountain glaciers could reach tipping points at which substantial and irreversible changes occur. Some scientists have concluded that the west Antarctic ice sheet may have already started melting irreversibly.
Our modelling showed that the risk of catastrophic wildfires is substantially higher during a temporary overshoot that culminates in 1.9°C of warming, particularly in regions already vulnerable to wildfires. Fires in California in early 2025 are an example of what is possible when the global temperature is higher.
Our analysis showed that the risk of species going extinct at 2°C of warming is double that at 1.5°C. Insects are most at risk because they are less able to move between regions in response to the changing climate than larger mammals and birds.
The impacts on society
Only armed conflict is considered by experts to have a greater impact on society than extreme weather. Forecasting how extreme weather will be affected by climate change is challenging. Scientists expect more intense storms, floods and droughts, but not necessarily in places that already regularly suffer these extremes.
In some places, moderate floods may reduce in size while larger, more extreme events occur more often and cause more damage. We are confident that the sea level would rise faster in a temporary overshoot scenario, and further increase the risk of flooding. We also expect more extreme floods and droughts, and for them to cause more damage to water and sanitation systems.
Floods and droughts will affect food production too. We found that impact studies have probably underestimated the crop damage that increases in extreme weather and water scarcity in key production areas during a temporary overshoot would cause.
We know that heatwaves become more frequent and intense as temperatures increase. More scarce food and water would increase the health risks of heat exposure beyond 1.5°C. It is particularly difficult to estimate the overall impact of overshooting this temperature limit when several impacts reinforce each other in this way.
In fact, most alarming of all is how uncertain much of our knowledge is.
For example, we have little confidence in estimates of how climate change will affect the economy. Some academics use models to predict how crops and other economic assets will be affected by climate change; others infer what will happen by projecting real-word economic losses to date into future warming scenarios. For 3°C of warming, estimates of the annual impact on GDP using models range from -5% to +3% each year, but up to -55% using the latter approach.
We have not managed to reconcile the differences between these methods. The highest estimates account for changes in extreme weather due to climate change, which are particularly difficult to determine.
We carried out an economic analysis using estimates of climate damage from both models and observed climate-related losses. We found that temporarily overshooting 1.5°C would reduce global GDP compared with not overshooting it, even if economic damages were lower than we expect. The economic consequences for the global economy could be profound.
So, what can we say for certain? First, that temporarily overshooting 1.5°C would be more costly to society and to the natural world than not overshooting it. Second, our projections are relatively conservative. It is likely that impacts would be worse, and possibly much worse, than we estimate.
Fundamentally, every increment of global temperature rise will worsen impacts on us and the rest of the natural world. We should aim to minimise global warming as much as possible, rather than focus on a particular target.
It would be hard to think of an industry less obviously “woke” than banking, but that’s how coalition partner NZ First has characterised certain practices within the finance sector.
Known as the “environmental, social and governance (ESG) framework”, such policies are designed to guide how a bank manages risks and opportunities beyond basic profit and loss.
NZ First’s bill seeks to ensure no New Zealand business can be denied banking services unless the decision is grounded in law. Its proponents argue it will prevent ESG standards from perpetuating “woke ideology” in the banking sector, driven by what they describe as “unelected, globalist, climate radicals”.
Prime Minister Christopher Luxon has supported the bill’s aims, recently calling it “utterly unacceptable” that petrol stations and mines were being denied banking services due to banks’ commitment to climate change goals.
Much of this is largely politically performative, however. A broader international trend has, for some time now, seen financial institutions increasingly aligning their lending practices with ESG criteria.
In Europe, for example, data from the European Banking Authority show banks have halved their exposures to mining firms since 2020, reflecting that global shift towards sustainability and risk management.
This is about more than “woke” agendas and is unlikely to reverse, given current global efforts to decarbonise. Encouraging or forcing banks to invest in carbon-emitting industries introduces financial risk. If those assets lose value, it constitutes irresponsible lending.
While the current US administration may be embracing fossil fuel industries, consumer and investor demand for sustainable policies is still strong. When banks such as the BNZ prepare for an orderly exit from declining industries, they are simply engaging in risk management.
Banks also manage regulatory risk. While the current government may enact the bill and force banks to invest in carbon-emitting industries, a future government could reverse that policy. This undermines long-term investment strategies.
Regulatory uncertainty
There is also a danger New Zealand is perceived internationally as not being serious about business and investment. In particular, the prime minister’s pressure on bank lending policies cuts across his stated commitment to the Paris Agreement on climate change.
The resulting regulatory uncertainty is counterproductive: it potentially deters international investors at a time when the government aims to attract foreign investment.
Ultimately, if bank lending policies lead to poor outcomes, it is ordinary New Zealanders who will likely bear the costs through higher interest rates or even bank failures.
In its eagerness to boost lending, the government is also encroaching on the Reserve Bank’s territory by directing it to prioritise competition, including reviewing risk weightings and capital thresholds (designed to build buffers against failure) for new entrants to the market.
But history shows that before the 2007-2009 global financial crisis, similar bank-friendly initiatives – often labelled “principles-based” – led to bad debt accumulation and increased economic vulnerability.
Institutional failure
The shift towards what we might call populist banking policies is not confined to New Zealand. Globally, there is a declining political interest in financial stability and prudential regulation.
For example, agreement on the “Basel III” reforms – developed in response to the global financial crisis and aimed at strengthening the regulation, supervision and risk management of banks – will likely be delayed by the Trump administration.
This will have ripple effects in Europe, Britain and the rest of the world, signalling a softening of global capital requirements. As Erik Thedéen, chair of the Basel Committee on Banking Supervision, described this:
Shaving off a few basis points of capital will not unlock a wave of new lending, but it will weaken your resilience. More generally, being well capitalised is a competitive advantage for banks and their shareholders. It ensures they can continue to grow and invest in profitable projects across the financial cycle.
Politicians need to be very careful when interfering with bank supervision policies in general. They risk undermining the independence of crucial institutions, with real consequences.
Last year’s Nobel Prize for economics went to Daron Acemoglu, Simon Johnson and James A. Robinson for their “studies of how institutions are formed and affect prosperity”. Their warning is that institutional failure can lead to the failure of nations.
A resilient banking system
While New Zealand isn’t in such imminent danger, political leaders need to be aware that populist appeals to certain voter segments can lead to policies that undermine the banking system and economic growth, and disproportionately affect the most vulnerable.
As Stelios Haji-Ioannou, founder of low-cost airline EasyJet, once remarked: “if you think safety is expensive, try an accident”.
New Zealand needs to focus on policies that promote long-term financial stability, enhance productivity and sustainable economic growth. Globally, there needs to be a recommitment to prudential regulation to ensure the lessons of the global financial crisis are not forgotten.
Only by doing so can we build a resilient banking system that serves the interests of all, not just a privileged few.
Top image: Government scientists at NOAA collect and provide crucial public information about coastal conditions that businesses, individuals and other scientists rely on.
NOAA’s National Ocean Service
This article is republished from The Conversation under a Creative Commons license. Read the original article. __________________________________________________________________________________
Information on the internet might seem like it’s there forever, but it’s only as permanent as people choose to make it.
That’s apparent as the second Trump administration “floods the zone” with efforts to dismantle science agencies and the data and websites they use to communicate with the public. The targets range from public health and demographics to climate science.
We are a research librarian and policy scholar who belong to a network called the Public Environmental Data Partners, a coalition of nonprofits, archivists and researchers who rely on federal data in our analysis, advocacy and litigation and are working to ensure that data remains available to the public.
In just the first three weeks of Trump’s term, we saw agencies remove access to at least a dozen climate and environmental justice analysis tools. The new administration also scrubbed the phrase “climate change” from government websites, as well as terms like “resilience.”
Here’s why and how Public Environmental Data Partners and others are making sure that the climate science the public depends on is available forever.
Why government websites and data matter
The internet and the availability of data are necessary for innovation, research and daily life.
If the data and tools used to understand complex data are abruptly taken off the internet, the work of scientists, civil society organizations and government officials themselves can grind to a halt. The generation of scientific data and analysis by government scientists is also crucial. Many state governments run environmental protection and public health programs that depend on science and data collected by federal agencies.
Removing information from government websites also makes it harder for the public to effectively participate in key processes of democracy, including changes to regulations. When an agency proposes to repeal a rule, for example, it is required to solicit comments from the public, who often depend on government websites to find information relevant to the rule.
And when web resources are altered or taken offline, it breeds mistrust in both government and science. Government agencies have collected climate data, conducted complex analyses, provided funding and hosted data in a publicly accessible manner for years. People around the word understand climate change in large part because of U.S. federal data. Removing it deprives everyone of important information about their world.
The second Trump administration seems different, with more rapid and pervasive removal of information.
In response, groups involved in Public Environmental Data Partners have been archiving climate datasets our community has prioritized, uploading copies to public repositories and cataloging where and how to find them if they go missing from government websites.
Most federal agencies decreased their use of the phrase ‘climate change’ on websites during the first Trump administration, 2017-2020.Eric Nost, et al., 2021, CC BY
As of Feb. 13, 2025, we hadn’t seen the destruction of climate science records. Many of these data collection programs, such as those at NOAA or EPA’s Greenhouse Gas Reporting Program, are required by Congress. However, the administration had limited or eliminated access to a lot of data.
Maintaining tools for understanding climate change
We’ve seen a targeted effort to systematically remove tools like dashboards that summarize and visualize the social dimensions of climate change. For instance, the Climate and Economic Justice Screening Tool mapped low-income and other marginalized communities that are expected to experience severe climate changes, such as crop losses and wildfires. The mapping tool was taken offline shortly after Trump’s first set of executive orders.
Most of the original data behind the mapping tool, like the wildfire risk predictions, is still available, but is now harder to find and access. But because the mapping tool was developed as an open-source project, we were able to recreate it.
Preserving websites for the future
In some cases, entire webpages are offline. For instance, the page for the 25-year-old Climate Change Center at the Department of Transportation doesn’t exist anymore. The link just sends visitors back to the department’s homepage.
During Donald Trump’s first week back in office, the Department of Transportation removed its Climate Change Center webpage.Internet Archive Wayback Machine
Fortunately, our partners at the End of Term Web Archive have captured snapshots of millions of government webpages and made them accessible through the Internet Archive’s Wayback Machine. The group has done this after each administration since 2008.
If you are worried that certain data currently still available might disappear, consult this checklist from MIT Libraries. It provides steps for how you can help safeguard federal data.
Narrowing the knowledge sphere
What’s unclear is how far the administration will push its attempts to remove, block or hide climate data and science, and how successful it will be.
Already, a federal district court judge has ruled that the Centers for Disease Control and Prevention’s removal of access to public health resources that doctors rely on was harmful and arbitrary. These were putback online thanks to that ruling.
We worry that more data and information removals will narrow public understanding of climate change, leaving people, communities and economies unprepared and at greater risk. While data archiving efforts can stem the tide of removals to some extent, there is no replacement for the government research infrastructures that produce and share climate data.
When people arrived on the shores of Aotearoa New Zealand and began to turn the land to their needs, they set in motion great changes.
The landscape of today bears little resemblance to that of a mere thousand years ago. More than 70% of forest cover has been lost since human arrival. Native bush has been replaced by tussocks, scrublands and, most of all, open agricultural land.
These changes affected our birdlife dramatically. Some species, like the moa, were simply hunted to extinction. Others fell directly to mammalian predators. Many species were victims of severe habitat destruction. The loss of suitable habitat remains a key conservation challenge to this day.
However, a changing distribution of plants is not a uniquely modern feature. New Zealand has seen equally radical shifts in habitat before – during the Ice Age, which lasted 2.6 million years and ended about 12,000 years ago.
This reconstruction shows the extend of glaciers during the height of the last Ice Age some 20,000 years ago.Shulmeister et al, 2019, CC BY-SA
At its height, parts of the country were up to 6°C colder than today, and glacial ice sheets spread wide fingers across the Southern Alps. The dry, cold climate resulted in widespread grass and scrubland. Forest cover became patchy everywhere except for the northern North Island.
Our new research tracks how bird life responded to these changes – in particular how exotic species took advantage of the shifting landscapes to make New Zealand home.
Ice Age invaders
Native birds responded to the Ice Age in a variety of ways. Kiwi populations became so isolated in forest patches they split into new lineages. Several moa species moved across the landscape, following their shifting habitat.
Some groups adapted, spreading into novel environments. Kea split off from their relatives the kākā, becoming more generalised. This is known as in situ adaptation; an existing group changing its habits or character to deal with new environments.
But where new ecological opportunities arise, species from elsewhere will also come to take advantage of them. Our research uncovers a pulse of colonisation by exotic bird species that coincides with the reduction of forest cover and the expansion of grasslands at the start of the Ice Age some 2.6 million years ago.
Many endemic New Zealand birds belong to young lineages that date back to landscape changes during the last Ice Age.Wikimedia Commons, Te Papa by Paul Martinson, CC BY-SA
These species were primarily generalists, able to take advantage of a variety of habitats. But there was also an influx of birds pre-adapted to more open conditions, such as the ancestors of Haast’s eagle, pūtangitangi (paradise shelduck) and pīhoihoi (pipit).
Where did these “invaders” come from? Principally, from Australia. For millions of years, they have ridden the winds across the Tasman Sea and, occasionally, established breeding colonies on our shores.
Over a long enough time, those new populations evolved to become distinct, endemic New Zealand species found nowhere else on earth. Pīwakawaka (fantail), ruru (morepork), weweia (dabchick) and kakī (black stilt), to name a few, are all descended from Ice Age Australian ancestors.
They arrived in a New Zealand characterised by scrub, tussock and grass during cold glacial periods, followed by slowly expanding forests during warmer interglacials.
History repeats itself
Today, open vistas once again dominate the landscape. This time they were sculpted by humans rather than a cooling climate. The changing environment means new ecological opportunities – and vacancies – have been left by the great number of species that have gone extinct.
The open landscapes of today mirror the impacts of the Ice Age. Forest cover is reduced, grass and scrub cover the North and South islands.Lubbe et al, 2025, CC BY-SA
Silvereyes have been here longer, first reported during the 1850s, while glossy ibis and barn owl only started breeding here this century. All likely flew across the Tasman to settle here.
Some arrivals seem to serve as ecological replacements of a kind. The kāhu (swamp harrier) is a stand-in for the now-extinct Eyles’ harrier and Haast’s eagle. The poaka (pied stilt) is a common sight where kakī once dominated. And Australian coots proliferate where New Zealand coots once waded.
Native habitats for native birds
These birds are following ancient patterns and processes. Where new opportunities appear, new organisms will rise to fill them. Our highly modified ecosystems are responding in the only way open to them, with exotic species expanding their range to take advantage of empty ecological niches – job vacancies in the ecosystem.
Indeed, these invasions are likely to become more frequent as species distributions shift in a warming climate. As our native species decline under threats of habitat loss and predation by mammalian pests, they will be ecologically replaced by other species.
Left to their own devices, Aotearoa’s plants and animals will look different in the future. The unique species that have called these islands home for millions of years will increasingly be replaced by more generalist species from elsewhere.
The route to protecting our native species in a fast changing world remains as clear as ever – protect and restore native habitat and eradicate mammalian predators.
Observing Greenland from a helicopter, the main problem is one of comprehending scale. I have thought we were skimming low over the waves of a fjord, before noticing the tiny shadow of a seabird far below and realising what I suspected were floating shards of ice were in fact icebergs the size of office blocks. I have thought we were hovering high in the sky over a featureless icy plane below, before bumping down gently onto ice only a few metres below us.
Crevasses – cracks in the surface of glaciers – are the epitome of this baffling range of scales. Formed by stresses at the surface, their direction and size tell us how the ice sheet is flowing towards the ocean. Inland, far away from the fast-flowing glaciers that discharge hundreds of gigatonnes of icebergs a year into fjords, crevasses can be tiny cracks only millimetres wide.
As the ice speeds up, they can be metres in diameter, sometimes covered by deceptive snow bridges that require suitable safety equipment and rescue training to traverse. Finally, where the ice meets the ocean and no scientist would ever dare to stand, they can be monsters over 100 metres from wall to wall. And across Greenland, they are growing.
Cracks you could fly a helicopter through.Tom Chudley
It shouldn’t be particularly surprising to scientists that crevasses are getting larger across Greenland. As the ocean warms, the ice sheet has sped up in response, increasing the stresses acting upon its surface. However, observations from satellites and in-person fieldwork are so poor that to date, we had no idea how extensively or quickly this process has been occurring.
Mapping cracks
In a new study, my colleagues and I mapped crevasses across the entirety of the Greenland ice sheet in 2016 and 2021. To do this, we used the “ArcticDEM”: three-dimensional surface maps of the polar regions based on high resolution satellite images. By applying image-processing techniques to over 8,000 maps, we could estimate how much water, snow or air would be needed to “fill” each crevasse across the ice sheet. This enabled us to calculate their depth and volume, and examine how they evolved.
We found that from 2016 to 2021, there were significant increases in crevasse volume across fast-flowing sectors of the Greenland ice sheet. In the southeast of the ice sheet, an area that has been particularly vulnerable to ocean-induced acceleration and retreat in the past few years, crevasse volume increased by over 25%.
In most Greenland glaciers that flow into the ocean, scientists found crevasses are increasing in size and depth.Chudley et al / Nature Geoscience
However, against our expectations, crevasse volume across the whole ice sheet increased by only 4.3%. That’s much closer to an overall balance than the extremes observed in certain sectors. What had happened? In fact, the significant increases elsewhere were being offset by a single source: an outlet glacier known as Sermeq Kujalleq (Danish: Jakobshavn Isbræ).
Sermeq Kujalleq is the fastest-flowing glacier on the planet, reaching speeds of nearly 50 metres a day and providing an outsized proportion of Greenland’s total sea-level rise contribution. In 2016, responding to an influx of cold water from the north Atlantic ocean, the glacier slowed and thickened. As it did this, the crevasses on the surface began to close – offsetting increases across the rest of the ice sheet.
This slowdown was short-lived. Since 2018, Sermeq Kujalleq has once again reverted to acceleration and thinning in response to ongoing warming. We won’t be able to rely on it to offset ice-sheet-wide increases in crevassing in the future.
Cracks grow into icebergs
Crevasses play an integral part in the life cycle of glaciers, and as they grow they hold the potential to further accelerate ice-sheet loss. They deliver surface meltwater into the belly of the ice sheet: once inside, water can act to warm the ice or lubricate the bed that the glacier slides over, both of which can make the ice sheet flow faster into the ocean. Meanwhile, where the ice meets the sea, crevasses form the initial fractures from which icebergs can break off, increasing the output of icebergs into the ocean.
Where Sermeq Kujalleq, or Jakobshavn Glacier, meets the sea. That iceberg filled fjord is several miles wide.Copernicus Sentinel / lavizzara / shutterstock
In short, crevasses underpin the dynamic processes that occur across Greenland and Antarctica. However, these processes are very poorly understood, and their future evolution is the single largest uncertainty in our predictions of sea-level rise. Together, the increased discharge of ice holds the potential to add up to 10 metres of additional sea-level rise by 2300 (75% of all cities with more than 5 million inhabitants exist less than 10m above sea level). We need to better understand these processes – including crevasses – so that informed sea-level projections can form the basis of our responses to the global challenges that climate change presents.
Since 2023, an international coalition of polar scientists has been urging the world to limit warming to 1.5˚C to avoid the most catastrophic melt scenarios for global glaciers and ice sheets. Last month, the EU’s Copernicus Climate Change Service confirmed that 2024 was the first year in which average global temperatures exceeded this threshold.
Every fraction of a degree matters. We may still be able to save ourselves from the worst of the damage the climate change will bring – but we are desperately running out of time.
Under the landmark 2015 Paris Agreement on climate change, humanity is seeking to reduce greenhouse gas emissions and keep planetary heating to no more than 1.5°C above the pre-industrial average. In 2024, temperatures on Earth surpassed that limit.
This was not enough to declare the Paris threshold had been crossed, because the temperature goals under the agreement are measured over several decades, rather than short excursions over the 1.5°C mark.
But the two papers just released use a different measure. Both examined historical climate data to determine whether very hot years in the recent past were a sign that a future, long-term warming threshold would be breached.
The answer, alarmingly, was yes. The researchers say the record-hot 2024 indicates Earth is passing the 1.5°C limit, beyond which scientists predict catastrophic harm to the natural systems that support life on Earth.
2024: the first year of many above 1.5°C
Climate organisations around the world agree last year was the hottest on record. The global average temperature in 2024 was about 1.6°C above the average temperatures in the late-19th century, before humans started burning fossil fuels at large scale.
Earth has also recently experienced individual days and months above the 1.5°C warming mark.
But the global temperature varies from one year to the next. For example, the 2024 temperature spike, while in large part due to climate change, was also driven by a natural El Niño pattern early in the year. That pattern has dissipated for now, and 2025 is forecast to be a little cooler.
These year-to-year fluctuations mean climate scientists don’t view a single year exceeding the 1.5°C mark as a failure to meet the Paris Agreement.
However, the new studies published today in Nature Climate Change suggest even a single month or year at 1.5°C global warming may signify Earth is entering a long-term breach of that vital threshold.
What the studies found
The studies were conducted independently by researchers in Europe and Canada. They tackled the same basic question: is a year above 1.5°C global warming a warning sign that we’re already crossing the Paris Agreement threshold?
Both studies used observations and climate model simulations to address this question, with slightly different approaches.
In the European paper, the researchers looked at historical warming trends. They found when Earth’s average temperature reached a certain threshold, the following 20-year period also reached that threshold.
This pattern suggests that, given Earth reached 1.5°C warming last year, we may have entered a 20-year warming period when average temperatures will also reach 1.5°C.
The Canadian paper involved month-to-month data. June last year was the 12th consecutive month of temperatures above the 1.5°C warming level. The researcher found 12 consecutive months above a climate threshold indicates the threshold will be reached over the long term.
Both studies also demonstrate that even if stringent emissions reduction begins now, Earth is still likely to be crossing the 1.5°C threshold.
Heading in the wrong direction
Given these findings, what humanity does next is crucial.
For decades, climate scientists have warned burning fossil fuels for energy releases carbon dioxide and other gases that are warming the planet.
But humanity’s greenhouse gas emissions have continued to increase. Since the Intergovernmental Panel on Climate Change released its first report in 1990, the world’s annual carbon dioxide emissions have risen about 50%.
Put simply, we are not even moving in the right direction, let alone at the required pace.
The science shows greenhouse gas emissions must reach net-zero to end global warming. Even then, some aspects of the climate will continue to change for many centuries, because some regional warming, especially in the oceans, is already locked in and irreversible.
If Earth has indeed already crossed the 1.5°C mark, and humanity wants to get below the threshold again, we will need to cool the planet by reaching “net-negative emissions” – removing more greenhouse gases from the atmosphere than we emit. This would be a highly challenging task.
Feeling the heat
The damaging effects of climate change are already being felt across the globe. The harm will be even worse for future generations.
Australia has already experienced 1.5°C of warming, on average, since 1910.
Our unique ecosystems, such as the Great Barrier Reef, are already suffering because of this warming. Our oceans are hotter and seas are rising, hammering our coastlines and threatening marine life.
These studies are a sobering reminder of how far short humanity is falling in tackling climate change.
They show we must urgently adapt to further global warming. Among the suite of changes needed, richer nations must support the poorer countries set to bear the most severe climate harms. While some progress has been made in this regard, far more is needed.
A major shift is also needed to decarbonise our societies and economies. There is still room for hope, but we must not delay action. Otherwise, humanity will keep warming the planet and causing further damage.
It’s now official. Last year was the warmest year on record globally and the first to exceed 1.5°C above pre-industrial levels. This doesn’t mean it’s too late to rein in further warming, but the ambition required rises with each delay in action.
New Zealand is no exception. Current climate policies are no longer a sufficient contribution to the global effort to keep warming at 1.5°C, according to the Climate Change Commission’s first review of the country’s 2050 climate target.
New Zealand’s current 2050 target has two components. Methane emissions from livestock must be cut by 24% to 47% below 2017 levels and emissions of all other greenhouse gases must reach net zero. But the commission has made three main recommendations to raise ambition:
a net negative target for emissions of long-lived gases (carbon dioxide and nitrous oxide) by removing 20 million tonnes more from the atmosphere than is released each year
a higher target range for biogenic methane emissions to reach at least 35% to 47% below 2017 levels
and the inclusion of emissions from international shipping and aviation.
The commission says these changes would bring New Zealand closer to “net zero for all gases”, in line with what is needed to achieve the goals of the Paris Agreement.
The 2050 target review was the last effort for the commission’s outgoing founding chair, Rod Carr, who has become a significant voice for climate action. In his closing words to parliament, he said:
Those who continue to promote the combustion of fossil fuels in the open air without permanent carbon capture and storage are, in my view, committing a crime against humanity.
The threshold for recommending a change is high. The commission must consider nine key areas and find “significant” developments that justify recommending a different target.
It found three significant changes occurred since the current target was set in 2019.
1. Global action is ahead of New Zealand
While other countries’ current policies, pledges or targets are not sufficient to keep temperature rise at 1.5°C, many countries now have more ambitious targets than New Zealand.
Australia, Japan, US, Canada, EU and Ireland all adopted full net-zero targets in 2021. Finland and Germany have or are considering net negative targets. Among countries with high biogenic methane emissions, several now have full net-zero targets.
2. Scientific understanding of climate change has changed
Climate impacts are appearing sooner and with more severity than the scientific community understood when the target was set in 2019.
3. The burden shifts to future generations
The increased risks and impacts of climate change have implications for inter-generational equity. Delaying action shifts costs and risks to future generations.
The commission’s report also explores New Zealand’s reliance on large-scale commercial exotic afforestation to meet its climate targets. This is one reason why Climate Action Tracker rates New Zealand’s response as highly insufficient and commensurate with a 4°C world.
Carbon in trees is part of the biosphere and will never be stored as permanently as fossil carbon. To take a case in point, Cyclone Gabrielle in 2023 (made worse by climate change) damaged forests, farms and infrastructure, and removed the social licence for forestry in the region.
How the recommended target was set
The commission’s work is tightly prescribed by law. It looked at four possible ways of sharing the global 1.5°C task: equal per capita emissions, national capacity, responsibility for historic warming and the right of all peoples to sustainable development.
New Zealand’s current target does not meet any of these standards, but the commission says the new target would at least meet the “national capacity” criterion and would be feasible and acceptable. However, it would still see New Zealand contributing two to three times its share of global warming this century.
The commission’s assessment is independent of any global warming metrics such as GWP100 (currently the UN standard). Instead, the commission computed New Zealand’s historical and future contribution to temperature rise directly. Both commonly used historical baselines, 1850 and 1990, yield similar results.
New Zealand’s government is currently particularly at odds with the commission’s recommendation on biogenic methane. It appointed a separate advisory panel last year which put forward a target consistent with causing “no additional warming” to the planet from agricultural methane emissions.
This graph shows the contribution to warming from emissions in New Zealand (1850–2100) under the current 2050 target.Climate Change Commission, CC BY-SA
But the commission rejects this idea, finding that unless the rest of New Zealand’s target were to be strengthened significantly, this would not be consistent with the Paris Agreement or the country’s own climate law.
International aviation and shipping emissions
In a quirk of climate diplomacy, international aviation and shipping emissions were excluded from the original 2050 target. But as the commission points out, they most definitely contribute to global warming and are covered by the temperature target of the Paris Agreement.
Other countries are moving in these areas and the International Civil Aviation and maritime organisations have net zero 2050 goals in place. Air New Zealand and the global shipping giant Maersk both support including these emissions in the 2050 target, which the commission finds to be achievable under multiple different pathways.
New Zealand’s dependence on shipping and air transport is a challenge. The commission puts the combined emissions from these sectors at 6.7 megatonnes – 20% of total CO₂ emissions and close to all industrial or all passenger car emissions. The aviation industry in particular is planning for growth, which, unless addressed, will blow the 1.5°C carbon budget both for New Zealand and globally.
Drawing on “net zero pathways” prepared by the international aviation and shipping industries, the commission finds that including these sources in New Zealand’s revised 2050 target would be achievable. The sectors would not necessarily have to enter the Emissions Trading Scheme, but the status quo (under which these sectors do not attract GST, fuel tax or a carbon charge) is inequitable with other sources of economic activity.
The author acknowledges the assistance and contribution by Paul Callister.
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In my new research, I argue the time has come for the dairy sector to adopt a “just transition” framework to achieve a fair and more sustainable food future and to navigate the disruptions from alternative protein industries.
The concept of a just transition is typically applied to the energy sector in shifting from fossil fuels to renewable energy sources.
But a growing body of research and advocacy is calling for the same principles to be applied to food systems, especially for shifting away from intensive animal agriculture.
Aotearoa New Zealand’s dairy sector is an exemplary case study for examining the possibilities of a just transition because it is so interconnected in the global production and trade of dairy, with 95% of domestic milk production exported as whole-milk powder to more than 130 countries.
Environmental and economic challenges
New Zealand’s dairy sector faces significant threats. This includes environmental challenges such as alarming levels of nitrate pollution in waterways caused by intensive agriculture.
This means livestock farmers, agricultural processors, fertiliser importers and manufacturers won’t have to pay for on-farm emissions. Instead, the government intends to implement a pricing system outside the Emissions Trading Scheme by 2030. To meet emissions targets, it relies on the development of technologies such as methane inhibitors.
The development of plant-based and fermentation proteins poses another threat to the dairy sector.Getty Images
In addition to environmental challenges, global growth and domestic initiatives in the development of alternative dairy products are changing the future of milk production and consumption.
New Zealand dairy giant Fonterra is pursuing the growth of alternative dairy with significant investments in a partnership with Dutch multinational corporation Royal-DSM. This supports precision fermentation start-up Vivici, which already has market-ready products such as whey protein powder and protein water.
Fonterra’s annual report states it anticipates a rise in customer preference towards dairy alternatives (plant-based or precision-fermentation dairy) due to climate-related concerns. The company says these shifting preferences could pose significant business risks for future dairy production if sustainability expectations cannot be met.
Pathways to a just transition for dairy
What happens when one the pillars of the economy becomes a major contributor to environmental degradation and undermines its own sustainability? Nitrate pollution and methane emissions threaten the quality of the land and waterways the dairy sector depends on.
In my recent study which draws on interviews with people across New Zealand’s dairy sector, three key transition pathways are identified, which address future challenges and opportunities.
Deintensification: reducing the number of dairy cows per farm.
Diversification: introducing a broader range of farming practices, landuse options and market opportunities.
Dairy alternatives: government and industry support to help farmers
participate in emerging plant-based and precision-fermentation industries.
While the pathways are not mutually exclusive, they highlight the socioeconomic and environmental implications of rural change which require active participation and engagement between the farming community and policy makers.
The Ministry of Business, Innovation and Employment recently published a guide to just transitions. It maps out general principles such as social justice and job security.
For the dairy transition to be fair and sustainable, we need buy-in from leadership and support from government, the dairy sector and the emerging alternative dairy industry to help primary producers and rural communities. This needs to be specific to different regions and farming methods.
The future of New Zealand’s dairy industry depends on its ability to adapt. Climate adaptation demands balancing social license, sustainable practices and disruptions from novel protein technologies.
