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For days, the city of 14 million people has been enveloped by smog, a mix of fog and pollutants caused by low-grade diesel fumes, smoke from seasonal agricultural burning and winter cooling.

The air quality index, which measures a range of pollutants, exceeded 1,000 on Saturday—well above the level of 300 considered "dangerous"—according to data from IQAir. The Punjab government also recorded peaks of over 1,000 on Sunday, which it considered "unprecedented".

"Weather forecast for the next six days shows that wind patterns will remain the same. Therefore we are closing all government and private primary schools in Lahore for a week," Jahangir Anwar, a senior environmental protection official in Lahore told AFP.

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"This smog is very harmful for children. Masks should be mandatory in schools. We are keeping an eye on the health of children in senior classes," Punjab senior minister Marriyum Aurangzeb told a news conference Sunday.

Smog counters have been established in hospitals, she added.

Breathing the toxic air has catastrophic health consequences, with the WHO saying strokes, heart disease, lung cancer and respiratory diseases can be triggered by prolonged exposure.

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Government offices and private companies will have half their staff work from home starting Monday.

Children are particularly vulnerable because they have less developed lungs and breathe more rapidly, taking in more air relative to their size than adults.

Last month, authorities banned schoolchildren from outdoor exercise until January and adjusted school hours to prevent children from traveling when the pollution is most punishing.

Pollution in excess of levels deemed safe by the WHO shortens the life expectancy of Lahore residents by an average of 7.5 years, according to the University of Chicago's Energy Policy Institute.

According to UNICEF, nearly 600 million children in South Asia are exposed to high levels of air pollution and half of childhood pneumonia deaths are associated with air pollution.

Signs that progress was lacking were clear from the outset of the meeting, with nearly all countries missing a deadline to submit official plans on how they will achieve the ambitious biodiversity targets set two years ago at COP15, including protecting 30 per cent of the planet’s land and oceans by 2030. A few more of these plans trickled in during the two weeks of the summit, including those from large countries like India and Argentina, but most countries’ strategies are still missing.

Going into COP16, it was clear the world is not on track to hit those targets. Since 2020, the area of the planet’s land and oceans under formal protections has increased just 0.5 per cent, according to a UN report released during the summit. That is a rate far too slow to protect 30 per cent of the planet by the end of the decade.

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Many lower-income countries said their failure to develop and submit plans by the deadline, let alone to begin carrying them out, was due to a dearth of financial resources. COP16 did see higher-income countries make pledges – totalling about $400 million – to help these efforts, but funds remain billions short of the $20 billion annual goal promised by 2025.

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Although COP16’s failure to move the needle on finance disappointed observers, the meeting did manage one key agreement: a deal on how to collect revenue from products developed using the planet’s genetic data. Before the meeting was suspended, countries agreed to urge pharmaceutical and other biotech companies that use such “digital sequence information” to contribute 0.1 per cent of revenue or 1 per cent of profits to a “Cali Fund”. This fund will be used to protect the biodiversity that is the source of such genetic data.

Submitter's note: It seems this voluntary tax is expected to support primarily indigenous populations. But without funding for biodiversity protection plans, habitat destruction will continue largely unabated. The voluntary tax itself would be woefully insufficient for empowering local populations to protect their ecosystems or their traditional lifestyles.

[...] UN estimates suggest the fund could raise up to a billion dollars a year for biodiversity. “It might raise some, but at nowhere near the scale or speed required,” says Pierre du Plessis, a long-time negotiator for the African Union.

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[T]he overall mood was dour. “A real shame of COP16 is that [debates on] digital sequence information sucked up the last drops of energy and time,” says Amber Scholz at the Leibniz Institute DSMZ in Germany.

One reason for the apparent lack of urgency is that the world treats climate change and biodiversity loss as two separate issues. The annual global climate summits are better attended and receive far more attention than the biodiversity negotiation – only six heads of state attended COP16, compared with the 154 who went to last year’s climate summit in Dubai, United Arab Emirates. That is a problem when the two issues are intertwined: climate change is one of the main threats to biodiversity, and the most biodiverse ecosystems are often also the best at storing carbon.

Abstract

Unabated 21st-century climate change will accelerate Arctic-Subarctic permafrost thaw which can intensify microbial degradation of carbon-rich soils, methane emissions, and global warming. The impact of permafrost thaw on future Arctic-Subarctic wildfires and the associated release of greenhouse gases and aerosols is less well understood. Here we present a comprehensive analysis of the effect of future permafrost thaw on land surface processes in the Arctic-Subarctic region using the CESM2 large ensemble forced by the SSP3-7.0 greenhouse gas emission scenario. Analyzing 50 greenhouse warming simulations, which capture the coupling between permafrost, hydrology, and atmosphere, we find that projected rapid permafrost thaw leads to massive soil drying, surface warming, and reduction of relative humidity over the Arctic-Subarctic region. These combined processes lead to nonlinear late-21st-century regime shifts in the coupled soil-hydrology system and rapid intensification of wildfires in western Siberia and Canada.

Abstract

The growth rate of the atmospheric abundance of methane (CH4) reached a record high of 15.4 ppb yr−1 between 2020 and 2022, but the mechanisms driving the accelerated CH4 growth have so far been unclear. In this work, we use measurements of the 13C:12C ratio of CH4 (expressed as δ13CCH4) from NOAA’s Global Greenhouse Gas Reference Network and a box model to investigate potential drivers for the rapid CH4 growth. These measurements show that the record-high CH4 growth in 2020–2022 was accompanied by a sharp decline in δ13CCH4, indicating that the increase in CH4 abundance was mainly driven by increased emissions from microbial sources such as wetlands, waste, and agriculture. We use our box model to reject increasing fossil fuel emissions or decreasing hydroxyl radical sink as the dominant driver for increasing global methane abundance.

Abstract

Under the Paris Agreement, signatory nations aim to keep global warming well below 2 °C above pre-industrial levels and preferably below 1.5 °C. This implicitly requires achieving net-zero or net-negative greenhouse gas emissions to ensure long-term global temperature stabilisation or reduction. Despite this requirement, there have been few analyses of stabilised climates, and there is a lack of model experiments to address our need for understanding the implications of the Paris Agreement. Here, we describe a new set of experiments using the Australian Community Climate and Earth System Simulator Earth system model (ACCESS-ESM-1.5) that enables the analysis of climate evolution under net-zero emissions, and we present initial results. Seven 1000-year-long simulations were run with global temperatures stabilising at levels in line with the Paris Agreement and at a range of higher global warming levels (GWLs). We provide an overview of the experimental design and use these simulations to demonstrate the consequences of delayed attainment of global net-zero carbon dioxide emissions. We show that there are substantial differences between transient and stabilising climate states and differences in stabilisation between GWLs. As the climate stabilises under net-zero emissions, we identify significant and robust changes in temperature and precipitation patterns including continued Southern Ocean warming and changes in regional precipitation trends. Changes under net-zero emissions differ greatly between regions, including contrasting trajectories of sea ice extent between the Arctic and Antarctic. We also examine the El Niño–Southern Oscillation (ENSO) and find evidence of reduced amplitude and frequency of ENSO events under climate stabilisation relative to projections under transient warming. An analysis at specific GWLs shows that significant regional changes continue for centuries after emission cessation and that these changes are stronger at higher GWLs. Our findings suggest substantial long-term climate changes are possible even under net-zero emission pathways. These simulations are available for use in the community and will hopefully motivate further experiments and analyses based on other Earth system models.

Sustainable planet for all, for very small values thereof.

Abstract

The Last Interglacial period (LIG) was characterized by a long-term Arctic atmospheric warming above the preindustrial level. The LIG thus provides a case study of Arctic feedback mechanisms of the cryosphere-ocean circulation-climate system under warm climatic conditions. Previous studies suggested a delay in the LIG peak warming in the North Atlantic compared to the Southern Ocean and evoked the possibility of southward extension of Arctic sea ice to the southern Norwegian Sea during the early LIG. Here we compile new and published proxy data on past changes in sea ice distribution, sea surface temperature and salinity, deep ocean convection, and meltwater sources based on well-dated records from the Norwegian Sea. Our data suggest that southward outflow of Arctic freshwater supressed Nordic Seas deep-water formation and northward oceanic heat transport during the early LIG. These findings showcase the complex feedback interactions between a warming climate, sea ice, ocean circulation and regional climate.

Abstract

Social movements have the power to drive large-scale social change but the effectiveness of disruptive tactics in achieving this change is uncertain. To shed light on this debate, we conducted nationally representative surveys before and after a week-long disruptive campaign to block London’s M25 motorway (November 2022) by the protest group Just Stop Oil (n = 1,415). Our results suggest that increased awareness of a radical group as a result of a highly publicized non-violent disruptive protest can increase identification with and support for more moderate climate groups (here, Friends of the Earth) in the span of only 2 weeks. Our study provides new insights into the dynamics of social movements and the role of radical protest in driving change. The positive radical flank effect observed here suggests that non-violent radical actions may constitute a largely untapped strategic resource for moderate groups within the broader climate movement.

Abstract

While the effects of climatic changes on migration have received widespread public and scientific attention, comparative evidence for their influence on internal migration worldwide remains scarce. Here we use census-based data from 72 countries (1960–2016) to analyse 107,840 migration flows between subnational regions. We find that increased drought and aridity have a significant impact on internal migration, particularly in the hyper-arid and arid areas of Southern Europe, South Asia, Africa and the Middle East and South America. Migration patterns are shaped by the wealth, agricultural dependency and urbanization of both origin and destination areas with migration responses being stronger in rural and predominantly agricultural areas. While overall climatic effects on migration are stronger in richer countries, we observe higher out-migration from poorer towards wealthier regions within countries. Furthermore, age and education groups respond differently to climatic stress, highlighting distinct mobility patterns of population subgroups across different geographic contexts.

Editor’s summary

Anthropogenic climate change has made wildfires bigger, hotter, and more common. Jones et al. used a machine learning approach to break down the “why” and “where” of the observed increases. The authors identified different forest ecoregions, grouped them into 12 global forest pyromes, and described their differing sensitivities to climate, humans, and vegetation. Their analysis shows how forest fire carbon emissions have increased in extratropical pyromes, where climate is the major control, overtaking emissions from the tropical pyromes, where human influence is most important. It also illustrates the increasing vulnerability of forests to fire disturbance under climate change. —Jesse Smith

Structured Abstract

INTRODUCTION

Forest fires are a natural disturbance mechanism made more likely by climate change, with major impacts on global forest ecosystems and carbon (C) storage. Recent trends show a worrying increase in forest fire activity, particularly in extratropical regions. This study aims to disentangle the factors driving the recent increases in fire activity by analyzing global forest fire extent and emissions and their relationship with climatic, human, and vegetation controls. Using machine learning, we grouped global forest ecoregions into 12 distinct pyromes in which forest fire extent depends on similar sets of controls.

RATIONALE

Understanding the drivers of fires in distinct pyromes is essential for developing targeted strategies to predict and manage fire risks. By grouping forest ecoregions into pyromes with distinct fire controls, we aimed to better understand the regional variations in fire dynamics and their sensitivity to climate change. This approach allows us to isolate the effects of climate change from other influencing factors such as land use and vegetation productivity.

RESULTS

Our analysis revealed that extratropical forest fire emissions have increased substantially under climate change. Fire emissions in one extratropical pyrome spanning boreal forests in Eurasia and North America nearly tripled between 2001 and 2023. This increase was linked to a rise in fire-favorable weather conditions, reduced soil moisture, and increased vegetation productivity. By contrast, tropical pyromes showed a decline in fire emissions linked to reduced deforestation fires in moist tropical forests and increased fragmentation of dry tropical forests with agriculture and other land uses. Overall, forest fire C emissions increased by 60% globally during the study period, with the most substantial contributions coming from extratropical regions. The increase in extratropical fire activity highlights the strong influence of climatic factors compared with human activities, which play a more dominant role in tropical regions. The increases in forest fire C emissions were explained both by changes in fire extent and by changes in fire severity (measured in terms of the C emitted per unit area burned by fire). In the extratropical forest pyromes, we observed major increases in fire severity alongside expansion of areas affected by fire. This finding shows that the intensity and severity of fires is increasing in extratropical forests, which is consistent with fires affecting drier, more flammable stocks of vegetation fuels as the climate warms and as droughts become more frequent.

CONCLUSION

The steep trend toward greater extratropical forest fire emissions is a warning of the growing vulnerability of forest C stocks to climate change. This poses a major challenge for global targets to tackle climate change, with fire reducing the capacity of forests to act as C sinks. Effective forest management and policies aimed at reducing greenhouse gas emissions are essential to mitigate these risks. Our study underscores the importance of considering regional distinctions in the controls on fire when developing strategies to manage fire and protect forest ecosystems. Proactive measures such as monitoring changes in vegetation and productivity can guide the prioritization of areas for forest management in the extratropics. In tropical pyromes, reducing ignitions during extreme fire-favorable weather and preventing forest fragmentation should protect forests and enhance C retention. In regions with substantial fire suppression history, shifting focus to managed, ecologically beneficial fires may prevent C sink-to-source conversion. Addressing the primary causes of climate change, particularly fossil fuel emissions, is central to minimizing future risks of forest fires globally and securing resilient forests for the future. In addition, our work supports growing calls for more comprehensive reporting of forest fire emissions to the United Nations as part of national reporting of anthropogenic C fluxes. The present norm of counting forest fire emissions fluxes as natural, on both managed and unmanaged land, is increasingly at odds with the observed growth in fire emission fluxes tied to anthropogenic climate change. This contributes to emerging gaps between the anthropogenic C budgets that are officially reported to the United Nations and the budgets constructed based on models and observations of terrestrial C stocks or atmospheric concentrations of CO2. Finally, we highlight the potential for major overestimation of C storage (and therefore C credits) by reafforestation schemes in extratropical forests if the growing risk of fire disturbance is not appropriately factored into accreditation protocols.

The loss of the Earth’s protective ozone layer would result in several years of extremely high ultraviolet (UV) light at the surface, a hazard to human health and food production. Most recent estimates indicate that the ozone loss after a global nuclear war would lead to a tropical UV index above 35, starting three years after the war and lasting for four years. The US Environmental Protection Agency considers a UV index of 11 to pose an “extreme” danger; 15 minutes of exposure to a UV index of 12 causes unprotected human skin to experience sunburn. Globally, the average sunlight in the UV-B range would increase by 20 percent. High levels of UV-B radiation are known to cause sunburn, photoaging, skin cancer, and cataracts in humans. They also inhibit the photolysis reaction required for leaf expansion and plant growth.