Waiting for others to act may be the best way to learn but, sometimes, taking action is the only way to teach yourself and others a useful lesson. Dare to act.

Today’s quote comes from American author and historian Edward Everett Hale, “I am only one, but I am one. I cannot do everything, but I can do something. And I will not let what I cannot do interfere with what I can do.”

Earth911 inspiration posters: Post them and share your desire to help people think of the planet first, every day. Click the poster to get a larger image.

The findings, based on research in mice and in human cells, are reported Nov. 22 in Cell. The research adds an important piece to the long-standing puzzle of itch and helps explain why common skin conditions like eczema and atopic dermatitis are often accompanied by persistent itch.

In such conditions, the equilibrium of microorganisms that keep our skin healthy is often thrown off balance, allowing S. aureus to flourish, the researchers said. Up until now, the itch that occurs with eczema and atopic dermatitis was believed to arise from the accompanying inflammation of the skin. But the new findings show that S. aureus single-handedly causes itch by instigating a molecular chain reaction that culminates in the urge to scratch.

“We’ve identified an entirely novel mechanism behind itch — the bacterium Staph aureus, which is found on almost every patient with the chronic condition atopic dermatitis. We show that itch can be caused by the microbe itself,” said senior author Isaac Chiu, associate professor of immunology in the Blavatnik Institute at HMS.

The study experiments showed that S. aureus releases a chemical that activates a protein on the nerve fibers that transmit signals from the skin to the brain. Treating animals with an FDA-approved anti-clotting medicine successfully blocked the activation of the protein to interrupt this key step in the itch-scratch cycle. The treatment relieved symptoms and minimized skin damage.

The findings can inform the design of oral medicines and topical creams to treat persistent itch that occurs with various conditions linked to an imbalance in the skin microbiome, such as atopic dermatitis, prurigo nodularis, and psoriasis.

The repeated scratching that is a hallmark of these conditions can cause skin damage and amplify inflammation.

“Itch can be quite debilitating in patients who suffer from chronic skin conditions. Many of these patients carry on their skin the very microbe we’ve now shown for the first time can induce itch,” said study first author Liwen Deng, a postdoctoral research fellow in the Chiu Lab.

Identifying the molecular spark plug that ignites itch

Researchers exposed the skin of mice to S. aureus. The animals developed intensifying itch over several days, and the repeated scratching caused worsening skin damage that spread beyond the original site of exposure.

Moreover, mice exposed to S. aureus became hypersensitive to innocuous stimuli that would not typically cause itch. The exposed mice were more likely than unexposed mice to develop abnormal itching in response to a light touch.

This hyperactive response, a condition called alloknesis, is common in patients with chronic conditions of the skin characterized by persistent itch. But it can also happen in people without any underlying conditions — think of that scratchy feeling you might get from a wool sweater.

To determine how the bacterium triggered itch, the researchers tested multiple modified versions of the S. aureus microbe that were engineered to lack specific pieces of the bug’s molecular makeup. The team focused on 10 enzymes known to be released by this microbe upon skin contact. One after another, the researchers eliminated nine suspects — showing that a bacterial enzyme called protease V8 was single-handedly responsible for initiating itch in mice. Human skin samples from patients with atopic dermatitis also had more S. aureus and higher V8 levels than healthy skin samples.

The analyses showed that V8 triggers itch by activating a protein called PAR1, which is found on skin neurons that originate in the spinal cord and carry various signals — touch, heat, pain, itch — from the skin to the brain. Normally, PAR1 lies dormant but upon contact with certain enzymes, including V8, it gets activated. The research showed that V8 snips one end of the PAR1 protein and awakens it. Experiments in mice showed that once activated, PAR1 initiates a signal that the brain eventually perceives as itch. When researchers repeated the experiments in lab dishes containing human neurons, they also responded to V8.

Interestingly, various immune cells implicated in skin allergies and classically known to cause itch — mast cells and basophils — did not drive itch after bacterial exposure, the experiments showed. Nor did inflammatory chemicals called interleukins, or white cells, which are activated during allergic reactions and are also known to be elevated in skin diseases and even in certain neurologic disorders.

“When we started the study, it was unclear whether the itch was a result of inflammation or not,” Deng said. “We show that these things can be decoupled, that you don’t necessarily have to have inflammation for the microbe to cause itch, but that the itch exacerbates inflammation on the skin.”

Interrupting the itch-scratch cycle

Because PAR1 — the protein activated by S. aureus — is involved in blood-clotting, researchers wanted to see whether an already approved anticlotting drug that blocks PAR1 would stop itch. It did.

The itchy mice whose skin was exposed to S. aureus experienced rapid improvement when treated with the drug. Their desire to scratch diminished dramatically, as did the skin damage caused by scratching.

Moreover, once treated with PAR1 blockers, the mice no longer experienced abnormal itch in response to innocuous stimuli.

The PAR1 blocker is already used in humans to prevent blood clots and could be repurposed as anti-itch medication. For example, the researchers noted, the active ingredient in the medicine could become the basis for anti-itch topical creams.

One immediate question that the researchers plan to explore in future work is whether other microbes besides S. aureus can trigger itch.

“We know that many microbes, including fungi, viruses, and bacteria, are accompanied by itch but how they cause itch is not clear,” Chiu said.

Beyond that, the findings raise a broader question: Why would a microbe cause itch? Evolutionarily speaking, what’s in it for the bacterium?

One possibility, the researchers said, is that pathogens may hijack itch and other neural reflexes to their advantage. For example, previous research has shown that the TB bacterium directly activates vagal neurons to cause cough, which might enable it to spread more easily from one host to another.

“It’s a speculation at this point, but the itch-scratch cycle could benefit the microbes and enable their spread to distant body sites and to uninfected hosts,” Deng said. “Why do we itch and scratch? Does it help us, or does it help the microbe? That’s something that we could follow up on in the future.”

The work was funded by the National Institutes of Health (grants R01AI168005, R01AI153185, R01NS065926, R01NS102161, R01NS111929, R37AI052453, R01AR076082, U01AI152038, UM1AI151958, R01AI153185, R01JL160582, F32AI172080, T32AI049928, 1R21AG075419), Food Allergy Science Initiative (FASI), Burroughs Wellcome Fund, Drako Family Fund, Jackson-Wijaya Research Fund, Canadian Institutes of Health Research (CIHR) (grants 376560 and 469411), and ANR-PARCURE (PRCE-CE18, 2020).

Chiu serves on the scientific advisory board of GSK Pharmaceuticals. Provisional patent application Serial No. 63/438,668, in which some coauthors are listed as inventors, was filed based on these findings.

As policymakers, researchers and climate activists from around the world prepare to meet for the UN Climate Change Conference beginning on November 30, 2023, one lingering question is whether climate technologies are developing and scaling quickly enough to meet the demands of the Paris Agreement.

New research led by Nemet, who is a professor in the La Follette School of Public Affairs, finds that novel CDR methods need to scale at a much faster rate to meet the Paris Agreement’s temperature goal of limiting warming to 2 or 1.5 degrees Celsius. That goal would require removing hundreds of gigatons of carbon dioxide from the atmosphere over the course of the century, making the scaling of novel CDR technologies particularly important.

CDR involves capturing CO2 from the atmosphere and storing it in a variety of ways. Examples of conventional CDR include reforestation, wetland restoration and improved forest management. All other CDR methods have only been deployed at small scale and are collectively known as novel CDR. Examples include bioenergy with carbon capture and sequestration, direct air carbon capture and storage, and biochar. These new methods may be able to offer more durable carbon storage than conventional methods that rely on trees and soils.

In one of their recent papers published October 30, 2023, in Communications, Earth & Environment, Nemet and his research team debut the Historical Adoption of TeCHnology (HATCH) dataset — an innovative project that tracks and analyzes a variety of agricultural, industrial and consumer technologies adopted over the past century that can provide insight into the scale-up of new technologies such as carbon removal.

The study analyzed the emergence and growth of 148 technologies across 11 categories going back to the early 20^th century. It then cross-referenced this data with model CDR scenarios established by the Intergovernmental Panel on Climate Change (IPCC), company announcements of CDR scale-up plans, and CDR targets in policy announcements.

While the paper found evidence that the required scale-up of carbon removal technologies fits within the historical range of previous efforts, company announcements and government targets implied there would be much faster growth than the historical record and IPCC CDR modeled scenarios.

“The scale-up rates needed for carbon removal to meet the 2- and 1.5-degree Celsius targets are within the range of historical experience, even if at the high end,” says Nemet. “We can learn from that experience to facilitate getting carbon removal to climate-relevant scale over the next three decades.”

In another paper published November 15, 2023, in Joule, Nemet and his research team find that 2 gigatons of carbon dioxide removal per year is currently taking place. Nearly all of that removal is accomplished by planting more trees and only 0.1% from novel CDR.

This is all despite modeling scenarios that show that we need to remove hundreds of gigatons of carbon dioxide from the atmosphere over the course of the century to meet the Paris Agreement and ensure the sustained wellbeing of our planet.

The study finds that virtually all scenarios that limit warming to 1.5 or 2 degrees Celsius require novel CDR. On average, scenarios increase novel CDR by a factor of 1,300 by mid-century.

By looking at the period of time between when a technology is introduced to the market and when rapid scale-up of its production occurs — called the formative phase — the paper suggests that this part of the process for direct air carbon capture and storage and other novel CDR methods must accelerate to meet the needs of a warming planet. Speeding up the innovation that occurs during this phase to begin a higher volume of production sooner could help improve technology adoption.

“To become climate relevant, the formative phases for air filter systems and other novel methods of carbon removal need to be at least as active as the fastest historical analogues,” says Jan Minx, head of the Mercator Research Institute on Global Commons and Climate Change working group Applied Sustainability Science and a co-author of both studies. “This will require more serious commitments toward novel removal technologies than are currently in place. The required levels will only be feasible if we see substantial development of novel CDR’s formative phase in the next 15 years.”

The results of these studies will also be included in the forthcoming 2023 UN Emissions Gap Report, which includes a chapter on carbon removal with contributions by Minx and Nemet.

Now scientists led by the University of East Anglia (UEA) and the British Antarctic Survey (BAS) are calling for a roadmap of polar ecosystems to fill that knowledge gap, preserve polar life and even protect “our everyday life and our planet’s health.” The study would map all biodiversity in those regions, from the atmosphere to the deep sea and from land to the oceans.

The authors said concerted action is required to mitigate the impact of warming on polar ecosystems via conservation efforts, to sustainably manage these unique habitats and their ecosystem services, and for the sustainable bioprospecting of novel genes and compounds for societal gain.

‘Multi-omics for studying and understanding polar life’, is published today in Nature Communications. The paper is co-authored by UEA, BAS and the University of Bielefeld, Germany.

Polar ecosystems are the most threatened because they are the most sensitive to global warming. They are being lost at a rapid pace and with them all the biology that provides ecosystem services and biology-driven regulation of the climate, including the carbon cycle.

Prof Thomas Mock, Professor of Marine Microbiology in UEA’s School of Environmental Sciences, is the joint lead author with Prof Melody Clark, Project Leader for the British Antarctic Survey.

Prof Thomas Mock said: “Biodiversity projections for the polar regions can only be reliably constructed if we have a sufficiently profound understanding of the diversity, ecological functions, and interrelations of polar organisms, as well as their resilience to climate change.

“These remote regions play substantial, often underappreciated, roles in the carbon cycle and drive global nutrient and dissolved organic matter fluxes. Consequently, polar environmental and ecological processes are intimately connected with our everyday life and our planet’s health, much of which is underpinned by the endemic biota, from viruses to large animals.

“There is strong evidence that climate-induced changes in the polar regions are already altering species distributions on land and in the sea, with major impacts on ecosystem function.”

Some species have shifted poleward, which has a knock-on effect on the food chain. Polar life, from microbes to seals, whales and polar bears, largely depends on overall low temperature and a substantial snow and ice cover, which are experiencing the impacts of global warming.

In the Arctic, temperatures are rising at least four times faster than elsewhere, destabilising the Arctic jet stream and increasing the likelihood of extreme weather events including heat waves, drought and flooding in temperate regions.

On land, permafrost melting and collapsing Arctic coastlines are dramatically altering ecological interactions and biogeochemistry due to the release of millennia-old carbon stores, trace elements, nutrients and potentially even deep-frozen ancient viruses and pathogenic bacteria.

In the oceans, the increased seasonal melting of sea ice is stabilizing surface waters too much, which reduces the amount of nutrients required for primary production to take place.

Similarly, the situation in the Southern Ocean and Antarctic continent is equally bleak, particularly for the Antarctic Peninsula, which has already experienced substantial levels of warming that has increased the loss of sea ice and glaciers.

The Southern Ocean is responsible for the uptake of three-quarters of the anthropogenic heat absorbed by the ocean and up to half of the carbon drawdown. It accounts for around 40 per cent of the global oceanic uptake of anthropogenic CO2 and around 50 per cent of the total atmospheric uptake. Furthermore, sequestering carbon by the organisms living in polar seas is probably the largest natural negative feedback against climate change.

The climate impacts on biodiversity and ecosystem functioning in both the Arctic and Antarctic serve as a bellwether for the consequences of global warming, including the persistence of biodiversity on Earth.

Prof Clark said: “Sequencing technologies have massively changed our abilities to decipher how organisms work. However the uptake in polar biology has been relatively low, especially when considering the tens of thousands of species that reside at the poles and are at threat in our warming world.

“Understanding how lots of very strange organisms living in extreme cold can help answer globally questions and provide real benefits for society. Failure to act now will result in a substantial loss of knowledge regarding evolutionary adaptation to the cold.”

Genomic screening not only offers the possibility of identifying populations under stress, but it can also be used for the monitoring of invasive species, thereby facilitating early interventions.

Prof Mock said: “With the cold regions of our planet diminishing, there is a real imperative to obtain full genome sequences for diverse organisms inhabiting polar ecosystems, from the deep oceans to the permafrost on land, for both the Arctic and Antarctic. This will enable the wider application of omics technologies to polar species, which will revolutionise our understanding of evolution in the cold and adaptive responses to a warming world.”

‘Multi-omics for studying and understanding polar life’, is published on 20 November 2023 in Nature Communications.

It’s hard to imagine an environmental impact from our online activities. After all, the virtual world is not a physical place. But computing uses much more electricity than just the battery in your laptop. Data centers use water to keep machines cool while they burn through all that electricity to process our data. And few online activities are as thirsty as the tech world’s latest darling, ChatGPT.

Unless you’ve been living completely off-grid this year, you’ve probably heard the buzz about ChatGPT and generative artificial intelligence (AI) products from Google, Meta, and other tech giants. But understanding it might be a different matter. ChatGPT is an AI tool released in November 2022 by the Microsoft-backed company OpenAI. Although ChatGPT gets most of the press, it’s not the only option for generative AI. All of them are designed to answer questions and follow instructions to complete tasks such as writing emails, articles, and code.

Since the release of ChatGPT, the ethical, economic, and data safety issues related to artificial intelligence have received a lot of attention. At the same time, potential environmental impacts have been largely overlooked. But that may be an enormous oversight. A forthcoming report from the University of California estimates that ChatGPT takes in almost 16 ounces of water for every series of 5 to 50 prompts or questions you ask it.

How Thirsty? 

Microsoft’s most recent environmental report revealed a sharp increase in water usage in 2022 when ChatGPT was introduced. In addition to AI, the culprits included more streaming video and gameplay. Microsoft’s global water consumption jumped 34% last year.

In 2022, Google reported its water consumption increased by 20%, which the UC researchers attributed to AI development. Google’s data centers in Iowa (where Microsoft’s AI supercomputers are also located) used the most water overall. Notably, Google’s facilities outside of Las Vegas, Nevada, increased water use most dramatically, doubling in just one year.

Data centers in hot climates like Nevada and Arizona require more water for the same amount of computing to cool computers than in cooler regions. For example, technology companies in Las Vegas use Colorado River water stored in Lake Mead. The water level of Lake Mead has dropped 150 feet since 2000, and the Colorado River dries up miles from the Gulf of California, which it hasn’t reached since 1980.

By contrast, Iowa generally does not suffer from the water supply issues experienced in the western states, so it is a better choice for locating data centers. But even Iowa needs to be mindful of water consumption. The state experienced drought over the past two years.

Conserving Water

Unfortunately, even if you don’t have a ChatGPT account, conserving water by avoiding artificial intelligence is not practical. You can save some water by writing your essays and resumes without resorting to ChatGPT. But these days, search engines nearly all use some form of generative AI. Hardcore AI avoiders can use Marginalia, a user-supported alternative to mainstream search engines that can support only 70 questions a minute, so the independent DIY search engine cannot meet everyone’s needs.

Tech companies have stated that they are working to reduce their water footprint. But only some people trust big tech to protect their data (and with good cause), let alone our planet. Boycotting the internet is not a practical option, either. But social media activism can sometimes have an effect, and investor opinions still matter. Take the time to vote if you own stock in tech companies, and ask management to reduce their impact. Unless you have a thick tech-stock portfolio, these efforts will likely make little difference.

Water use is one example of the wisdom of first putting your house in order. You will probably be more successful in saving water directly than trying to influence AI development.

In your home, repair leaks immediately and learn how to fix bad habits to save water in the bathroom and kitchen. When you replace your toilet, dishwasher, and clothes washer, choose the most efficient option you can afford. Do the same with your showerheads.

Outside your home, practice efficient irrigation in a water-wise garden. Consider eliminating your grass lawn or even xeriscaping. You can save water with your food choices, too.

If you’ve already improved your water habits, spend some energy directly encouraging companies and advocating for Congress to create incentives and penalties nudging corporations to be more efficient.

Despite this headline finding, the environmental scientists behind the research are quick to underline that this should in no way be taken to mean the world’s governments can take their foot off the brake in their obligations to reduce carbon emissions as fast as possible. Simply planting more trees and protecting existing vegetation is not a golden-bullet solution but the research does underline the multiple benefits to conserving such vegetation.

“Plants take up a substantial amount of carbon dioxide (CO₂) every year, thereby slowing down the detrimental effects of climate change, but the extent to which they will continue this CO₂ uptake into the future has been uncertain,” explains Dr Jürgen Knauer, who headed the research team led by the Hawkesbury Institute for the Environment at Western Sydney University.

“What we found is that a well-established climate model that is used to feed into global climate predictions made by the likes of the IPCC predicts stronger and sustained carbon uptake until the end of the 21^st century when it accounts for the impact of some critical physiological processes that govern how plants conduct photosynthesis.

“We accounted for aspects like how efficiently carbon dioxide can move through the interior of the leaf, how plants adjust to changes in temperatures, and how plants most economically distribute nutrients in their canopy. These are three really important mechanisms that affect a plant’s ability to ‘fix’ carbon, yet they are commonly ignored in most global models” said Dr Knauer.

Photosynthesis is the scientific term for the process in which plants convert — or “fix” — CO₂ into the sugars they use for growth and metabolism. This carbon fixing serves as a natural climate change mitigator by reducing the amount of carbon in the atmosphere; it is this increased uptake of CO₂ by vegetation that is the primary driver of an increasing land carbon sink reported over the last few decades.

However, the beneficial effect of climate change on vegetation carbon uptake might not last forever and it has long been unclear how vegetation will respond to CO₂, temperature and changes in rainfall that are significantly different from what is observed today. Scientists have thought that intense climate change such as more intense droughts and severe heat could significantly weaken the sink capacity of terrestrial ecosystems, for example.

In the study published this week, however, Knauer and colleagues present results from their modelling study set to assess a high-emission climate scenario, to test how vegetation carbon uptake would respond to global climate change until the end of the 21^st century.

The authors tested different versions of the model that varied in their complexity and realism of how plant physiological processes are accounted for. The simplest version ignored the three critical physiological mechanisms associated with photosynthesis while the most complex version accounted for all three mechanisms.

The results were clear: the more complex models that incorporated more of our current plant physiological understanding consistently projected stronger increases of vegetation carbon uptake globally. The processes accounted for re-enforced each other, so that effects were even stronger when accounted for in combination, which is what would happen in a real-world scenario.

Silvia Caldararu, Assistant Professor in Trinity’s School of Natural Sciences, was involved in the study. Contextualising the findings and their relevance, she said:

“Because the majority of terrestrial biosphere models used to assess the global carbon sink are located at the lower end of this complexity range, accounting only partially for these mechanisms or ignoring them altogether, it is likely that we are currently underestimating climate change effects on vegetation as well as its resilience to changes in climate. We often think about climate models as being all about physics, but biology plays a huge role and it is something that we really need to account for.

“These kinds of predictions have implications for nature-based solutions to climate change such as reforestation and afforestation and how much carbon such initiatives can take up. Our findings suggest these approaches could have a larger impact in mitigating climate change and over a longer time period than we thought.

“However, simply planting trees will not solve all our problems. We absolutely need to cut down emissions from all sectors. Trees alone cannot offer humanity a get out of jail free card.”

The paper, published in the Annual Review of Ecology, Evolution, and Systematics, highlights the interplay between the trend of climate warming and the fluctuations in local temperature. These two properties cause atypically warm events such as marine heatwaves to occur with increasing frequency and magnitude.

However, the interaction between the steadily warming climate and the spikes in local temperatures tends to be underappreciated, according to study co-author Jon Witman, a professor of biology at Brown University.

“Climate change studies often focus on the trend of global warming,” Witman said. “But organisms in the ocean are also experiencing temperature fluctuations, and that’s less studied and therefore less understood. What we’re trying to do is to add more reality into ocean climate change studies by considering both the smooth, upward trend of climate warming as well as the variability on top of that trend.”

The paper proposes a new approach for understanding and modeling the effects of marine climate change, with suggestions for future research.

Witman offered coral as an example that illustrates the need for a new approach. While an organism like coral is already trying to adapt to the trend of rising temperatures, he noted, it then endures a heat wave, which causes a large and sudden spike in temperature.

Temperature spikes tend to lead to coral bleaching, which is when metabolically stressed corals expel the beneficial microscopic algae living within them and turn white. If the temperature stays high and algae are unable to return to their host coral, the bleached coral will die.

Witman pointed to heat waves in the Mediterranean that have led to an increase in coral bleaching and death of corals and sea fans.

Extreme events such as heat waves may alter or damage marine ecosystems in ways that leave them more vulnerable to both progressive climate change as well as the next temperature fluctuation, Witman added. A more realistic model may help scientists better identify areas where coral is more likely to die off in an extreme event leaving coral-dependent organisms at risk over time, he said.

In other cases, temperature variability can lead to an opposite response in the affected organism: an ability to acclimatize or adapt to temperature extremes, depending on their frequency and intensity.

These responses to variable events like heat waves compound and are compounded by the effects caused by rapidly and steadily increasing ocean temperatures, Witman said.

Witman collaborated with Andrew Pershing of the nonprofit Climate Central, who studied biology as an undergraduate at Brown, and John Bruno, a professor of biology in the University of North Carolina at Chapel Hill, who earned a Ph.D. in ecology and evolutionary biology from Brown.

In their paper, Bruno, Pershing and Witman considered how organisms and communities adapt or adjust to both smooth trends and variable changes, and then reviewed processes that influence the rate at which marine communities adjust to changes in their physical environment — as well as those processes that might hamper adaption or acclimatization. The researchers stressed that all of these factors illustrate why it’s key to consider both types of change when studying marine climates.

“If we just study how organisms respond to the smooth trend, we miss all the variability, which is driving ecological change,” Witman said. “It’s not just a matter of worsening physiological stress over time; there are also variable events that have their own ripple effects.”

In the paper, the researchers created a global model that shows the variability in temperature relative to trend, highlighting regions where extreme temperatures are likely to have particularly deleterious effects. In the areas of the Gulf of Maine, the Caribbean Sea and the Mediterranean Sea, they write, there are high probabilities of exceptional warming events and “ecological surprises.” Research shows that key foundation species in these regions, such kelp and corals, have already experienced substantial climate-related changes.

“These areas, especially, warrant investigation to improve our understanding of what’s going to happen in the future — as well as our conception of what we’re calling, ‘the new ocean,'” Witman said.

This work was supported by the National Science Foundation, Biological Oceanography Program (OCE-2035354, OCE-1851866, OCE-2128592).

The Arctic is currently warming nearly four times faster than the global average rate. The new study, published in the journal Earth System Dynamics, aimed to estimate the impact of this faster warming on how quickly the global temperature thresholds of 1.5C and 2C, set down in the Paris Agreement, are likely to be breached.

To do this, the research team created alternative climate change projections in which rapid Arctic warming was not occurring. They then compared temperatures in this hypothetical world with those of the “real-world” models and examined the timing with which the critical Paris Agreement thresholds of 1.5C and 2C were breached. They found that, in the models without fast Arctic warming, the thresholds were breached five and eight years later respectively, than their “real-world” projected dates of 2031 and 2051.

In addition, they found that disproportionately fast Arctic warming, known as Arctic amplification, added disproportionate uncertainty to forecasts, as the variation in model projections for the region is larger than for the rest of the planet.

Alistair Duffey (UCL Earth Sciences), a PhD candidate and lead author of the study, said: “Our study highlights the global importance of rapid Arctic warming by quantifying its large impact on when we are likely to breach critical climate thresholds. Arctic warming also adds substantial uncertainty to climate forecasts.”

“These findings underscore the need for more extensive monitoring of temperatures in the region, both in-situ and via satellites, and for a better understanding of the processes occurring there, which can be used to improve forecasts of global temperature rise.”

The study does not attempt to quantify the ways in which Arctic warming affects the rest of the world, for instance through the retreat of sea ice which helps to keep the planet cool, but instead estimates the direct contribution of Arctic warming to global temperature increases.

Co-author Professor Julienne Stroeve (UCL Earth Sciences, the University of Manitoba, Canada, and the U.S. National Snow and Ice Data Center) said: “While our study focuses on how Arctic warming affects global temperature change, the local impacts should not be overlooked. A 2C temperature rise globally would result in a 4C annual mean rise in the Arctic, and a 7C rise in winter, with profound consequences for local people and ecosystems.

“In addition, rapid warming in the Arctic has global consequences that we do not account for in this study, including sea level rise and the thawing of permafrost which leads to more carbon being released into the air.”

Co-author Dr Robbie Mallett (University of Manitoba and Honorary Research Fellow at UCL Earth Sciences) said: “Arctic climate change is often overlooked by politicians because most of the region is outside national boundaries. Our study shows how much the Arctic impacts global targets like the Paris Agreement, and hopefully draws attention to the crisis that’s already unfolding in the region.”

Arctic amplification, which is strongest in the winter months, is caused by several factors. One is the retreat of sea ice, meaning more sunlight (and heat) is absorbed by water instead of being reflected back into space. Another factor is less vertical mixing of air in the poles than in the tropics, which keeps warmer air close to the Earth’s surface.

For the study, researchers looked at an ensemble of 40 climate models that informed the UN’s 2021 climate change report*. These models divide Earth’s surface into a three-dimensional grid of cells, modelling physical processes occurring within each cell.

The research team modified the output of the models to create an alternative world in which rapid Arctic warming was not occurring, by setting the rate of change of temperature in the region north of 66° North equal to that of the rest of the planet. They looked at how the removal of rapid Arctic warming would affect temperature projections in a plausible intermediate emissions scenario and calculated the average temperature projection across all models.

In addition, they looked at how removing rapid Arctic warming from the models would affect more pessimistic or optimistic scenarios. For example, in a more optimistic scenario, where emissions are cut sharply and net zero is reached shortly after 2050, Arctic amplification causes a seven-year difference in the time of passing 1.5°C.

Temperature projections for the Arctic varied more substantially between the models than for other parts of the globe, accounting for 15% of the uncertainty in projections, despite the region only making up 4% of the global surface area.

The 1.5C and 2C limits are regarded as having been breached when average global temperatures over a 20-year period are 1.5C or 2C higher than in pre-industrial times.

The goal of the Paris Agreement, an international treaty, is to keep the global average temperature to “well below 2°C above pre-industrial levels” and pursue efforts “to limit the temperature increase to 1.5°C.”

The Arctic is thought to have warmed by 2.7C since the pre-industrial era, and this warming is believed to have accelerated since the start of the 21^st century.

The study was supported by the Natural Environment Research Council (NERC), the European Space Agency (ESA), and the Canada 150 Research Chairs Program.

*The Intergovernmental Panel on Climate Change’s Sixth Assessment Report.