Global and Regional Trends and Drivers of Fire Under Climate Change

Reviews of Geophysics, Journal Year: 2022, Volume and Issue: 60(3)

Published: April 11, 2022

Abstract Recent wildfire outbreaks around the world have prompted concern that climate change is increasing fire incidence, threatening human livelihood and biodiversity, perpetuating change. Here, we review current understanding of impacts on weather (weather conditions conducive to ignition spread wildfires) consequences for regional activity as mediated by a range other bioclimatic factors (including vegetation biogeography, productivity lightning) ignition, suppression, land use). Through supplemental analyses, present stocktake trends in burned area (BA) during recent decades, examine how relates its drivers. Fire controls annual timing fires most regions also drives inter‐annual variability BA Mediterranean, Pacific US high latitude forests. Increases frequency extremity been globally pervasive due 1979–2019, meaning landscapes are primed burn more frequently. Correspondingly, increases ∼50% or higher seen some extratropical forest ecoregions including high‐latitude forests 2001–2019, though interannual remains large these regions. Nonetheless, can override relationship between weather. For example, savannahs strongly patterns fuel production fragmentation naturally fire‐prone agriculture. Similarly, tropical relate deforestation rates degradation than changing Overall, has reduced 27% past two part decline African savannahs. According models, prevalence already emerged beyond pre‐industrial Mediterranean change, emergence will become increasingly widespread at additional levels warming. Moreover, several major wildfires experienced years, Australian bushfires 2019/2020, occurred amidst were considerably likely Current models incompletely reproduce observed spatial based their existing representations relationships controls, historical vary across models. Advances observation controlling supporting addition optimization processes exerting upwards pressure intensity weather, this escalate with each increment global Improvements better interactions climate, extremes, humans required predict future mitigate against consequences.

Language: Английский

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Post-disturbance reorganization of forest ecosystems in a changing world

Proceedings of the National Academy of Sciences, Journal Year: 2022, Volume and Issue: 119(28)

Published: July 5, 2022

Forest ecosystems are strongly impacted by continuing climate change and increasing disturbance activity, but how forest dynamics will respond remains highly uncertain. Here, we argue that a short time window after (i.e., discrete event disrupts prevailing ecosystem structure composition releases resources) is pivotal for future development. Trees establish during this reorganization phase can shape centuries, providing operational early indications of change. While has been fruitfully studied through lens resilience, profound ecological changes be masked resilience versus regime shift dichotomy. We present framework characterizing the full spectrum disturbance, analyzing along dimensions (number, size, spatial arrangement trees) (identity diversity tree species). propose four major pathways which cover persist reorganize following disturbance: (no in composition), restructuring (structure does not), reassembly (composition replacement both change). Regime shifts occur when vegetation altered so profoundly emerging trajectory leads to nonforest. identify fundamental processes underpinning which, if disrupted, deflect away from resilience. To understand predict reorganization, assessing these traits modulating them crucial. A new wave experiments, measurements, models emphasizing further capacity anticipate dynamics.

Language: Английский

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Satellite observations document trends consistent with a boreal forest biome shift

Global Change Biology, Journal Year: 2022, Volume and Issue: 28(10), P. 3275 - 3292

Published: Feb. 24, 2022

The boreal forest biome is a major component of Earth's biosphere and climate system that projected to shift northward due continued change over the coming century. Indicators will likely first be evident along climatic margins include changes in vegetation productivity, mortality, recruitment, as well overall greenness. However, extent which already underway remains unclear because local nature most field studies, sparsity systematic ground-based ecological monitoring, reliance on coarse resolution satellite observations. Here, we evaluated early indicators using four decades moderate (30 m) observations biogeoclimatic spatial datasets. Specifically, quantified interannual trends annual maximum greenness an ensemble indices derived from Landsat at 100,000 sample sites areas without signs recent disturbance. We found increased (greened) 38 [29, 42] % 22 [15, 26] 1985 2019 2000 2019, whereas decreased (browned) 13 [9, 15] 15 [13, 19] during these respective periods [95% Monte Carlo confidence intervals]. Greening was thus 3.0 [2.6, 3.5] 1.5 [0.8, 2.0] times more common than browning primarily occurred cold sparsely treed with high soil nitrogen summer warming. Conversely, climatically warmest both types (e.g., evergreen conifer forests), especially densely where summers became warmer drier. These macroecological reflect underlying shifts recruitment are consistent stages shift.

Language: Английский

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Climate change: Strategies for mitigation and adaptation

The Innovation Geoscience, Journal Year: 2023, Volume and Issue: 1(1), P. 100015 - 100015

Published: Jan. 1, 2023

<p>The sustainability of life on Earth is under increasing threat due to human-induced climate change. This perilous change in the Earth's caused by increases carbon dioxide and other greenhouse gases atmosphere, primarily emissions associated with burning fossil fuels. Over next two three decades, effects change, such as heatwaves, wildfires, droughts, storms, floods, are expected worsen, posing greater risks human health global stability. These trends call for implementation mitigation adaptation strategies. Pollution environmental degradation exacerbate existing problems make people nature more susceptible In this review, we examine current state from different perspectives. We summarize evidence Earth’s spheres, discuss emission pathways drivers analyze impact health. also explore strategies highlight key challenges reversing adapting change.</p>

Language: Английский

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Reduced fire severity offers near-term buffer to climate-driven declines in conifer resilience across the western United States

Proceedings of the National Academy of Sciences, Journal Year: 2023, Volume and Issue: 120(11)

Published: March 6, 2023

Increasing fire severity and warmer, drier postfire conditions are making forests in the western United States (West) vulnerable to ecological transformation. Yet, relative importance of interactions between these drivers forest change remain unresolved, particularly over upcoming decades. Here, we assess how interactive impacts changing climate wildfire activity influenced conifer regeneration after 334 wildfires, using a dataset from 10,230 field plots. Our findings highlight declining capacity across West past four decades for eight dominant species studied. Postfire is sensitive high-severity fire, which limits seed availability, climate, influences seedling establishment. In near-term, projected differences recruitment probability low- scenarios were larger than most species, suggesting that reductions severity, resultant on could partially offset expected climate-driven declines regeneration. Across 40 42% study area, project be likely following low-severity but not under future (2031 2050). However, increasingly warm, dry eventually outweigh influence availability. The percent area considered unlikely experience regeneration, regardless increased 5% 1981 2000 26 31% by mid-century, highlighting limited time window management actions reduce may effectively support

Language: Английский

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Escalating carbon emissions from North American boreal forest wildfires and the climate mitigation potential of fire management

Science Advances, Journal Year: 2022, Volume and Issue: 8(17)

Published: April 27, 2022

Wildfires in boreal forests release large quantities of greenhouse gases to the atmosphere, exacerbating climate change. Here, we characterize magnitude recent and projected gross net North American wildfire carbon dioxide emissions, evaluate fire management as an emissions reduction strategy, quantify associated costs. Our results show that wildfires America could, by mid-century, contribute a cumulative source nearly 12 gigatonnes dioxide, about 3% remaining global with keeping temperatures within Paris Agreement's 1.5°C limit. With observations from Alaska, current practices limit burned area. Further, costs avoiding means increasing investment are comparable or lower than those other mitigation strategies. Together, our findings highlight risk pose point cost-effective way emissions.

Language: Английский

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Siberian taiga and tundra fire regimes from 2001–2020

Environmental Research Letters, Journal Year: 2022, Volume and Issue: 17(2), P. 025001 - 025001

Published: Jan. 18, 2022

Abstract Circum-boreal and -tundra systems are crucial carbon pools that experiencing amplified warming at risk of increasing wildfire activity. Changes in activity have broad implications for vegetation dynamics, underlying permafrost soils, ultimately, cycling. However, understanding effects on biophysical processes across eastern Siberian taiga tundra remains challenging because the lack an easily accessible annual fire perimeter database underestimation area burned by MODIS satellite imagery. To better understand dynamics over last 20 years this region, we mapped burned, generated a database, characterized regimes eight ecozones spanning 7.8 million km 2 from ∼61–72.5° N 100° E–176° W using long-term data Landsat, processed via Google Earth Engine. We composite images growing season (May–September), which allowed mitigation missing snow-cover, cloud-cover, Landsat 7 scan line error. used composites to calculate difference Normalized Burn Ratio (dNBR) each year. The dNBR were converted binary or unburned imagery was vectorize perimeters. 22 091 fires burning 152 hectares (Mha) years. Although 2003 largest year record, 2020 exceptional four northeastern resulting substantial increases above Arctic Circle. Increases extent, severity, frequency with continued climate will impact increased likelihood irreversible thaw leads release and/or conversion forest shrublands.

Language: Английский

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Mechanisms and Impacts of Earth System Tipping Elements

Reviews of Geophysics, Journal Year: 2023, Volume and Issue: 61(1)

Published: Feb. 16, 2023

Abstract Tipping elements are components of the Earth system which may respond nonlinearly to anthropogenic climate change by transitioning toward substantially different long‐term states upon passing key thresholds or “tipping points.” In some cases, such changes could produce additional greenhouse gas emissions radiative forcing that compound global warming. Improved understanding tipping is important for predicting future risks and their impacts. Here we review mechanisms, predictions, impacts, knowledge gaps associated with 10 notable proposed be elements. We evaluate approaching critical whether shifts manifest rapidly over longer timescales. Some have a higher risk crossing points under middle‐of‐the‐road pathways will possibly affect major ecosystems, patterns, and/or carbon cycling within 21st century. However, literature assessing scenarios indicates strong potential reduce impacts many through mitigation. The studies synthesized in our suggest most do not possess abrupt years, exhibit behavior, rather responding more predictably directly magnitude forcing. Nevertheless, uncertainties remain elements, highlighting an acute need further research modeling better constrain risks.

Language: Английский

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More than 17,000 tree species are at risk from rapid global change

Nature Communications, Journal Year: 2024, Volume and Issue: 15(1)

Published: Jan. 2, 2024

Abstract Trees are pivotal to global biodiversity and nature’s contributions people, yet accelerating changes threaten tree diversity, making accurate species extinction risk assessments necessary. To identify that require expert-based re-evaluation, we assess exposure change in six anthropogenic threats over the last two decades for 32,090 species. We estimated half (54.2%) of assessed have been exposed increasing threats. Only 8.7% these considered threatened by IUCN Red List, whereas they include more than Data Deficient (57.8%). These findings suggest a substantial underestimation associated current assessments. also map hotspots rapidly changing around world. Our data-driven approach can strengthen efforts going into List facilitating prioritization among allowing efficient conservation efforts.

Language: Английский

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State of Wildfires 2023–2024

Earth system science data, Journal Year: 2024, Volume and Issue: 16(8), P. 3601 - 3685

Published: Aug. 13, 2024

Abstract. Climate change contributes to the increased frequency and intensity of wildfires globally, with significant impacts on society environment. However, our understanding global distribution extreme fires remains skewed, primarily influenced by media coverage regionalised research efforts. This inaugural State Wildfires report systematically analyses fire activity worldwide, identifying events from March 2023–February 2024 season. We assess causes, predictability, attribution these climate land use forecast future risks under different scenarios. During 2023–2024 season, 3.9×106 km2 burned slightly below average previous seasons, but carbon (C) emissions were 16 % above average, totalling 2.4 Pg C. Global C record in Canadian boreal forests (over 9 times average) reduced low African savannahs. Notable included record-breaking extent Canada, largest recorded wildfire European Union (Greece), drought-driven western Amazonia northern parts South America, deadly Hawaii (100 deaths) Chile (131 deaths). Over 232 000 people evacuated Canada alone, highlighting severity human impact. Our revealed that multiple drivers needed cause areas activity. In Greece, a combination high weather an abundance dry fuels probability fires, whereas area anomalies weaker regions lower fuel loads higher direct suppression, particularly Canada. Fire prediction showed mild anomalous signal 1 2 months advance, Greece had shorter predictability horizons. Attribution indicated modelled up 40 %, 18 50 due during respectively. Meanwhile, seasons magnitudes has significantly anthropogenic change, 2.9–3.6-fold increase likelihood 20.0–28.5-fold Amazonia. By end century, similar magnitude 2023 are projected occur 6.3–10.8 more frequently medium–high emission scenario (SSP370). represents first annual effort catalogue events, explain their occurrence, predict risks. consolidating state-of-the-art science delivering key insights relevant policymakers, disaster management services, firefighting agencies, managers, we aim enhance society's resilience promote advances preparedness, mitigation, adaptation. New datasets presented this work available https://doi.org/10.5281/zenodo.11400539 (Jones et al., 2024) https://doi.org/10.5281/zenodo.11420742 (Kelley 2024a).

Language: Английский

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