Showing papers on "Global warming published in 2020"
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01 Jan 2020
TL;DR: In this article, the authors examined the detection of the greening signal, its causes and its consequences, and showed that greening is pronounced over intensively farmed or afforested areas, such as in China and India, reflecting human activities.
Abstract: Vegetation greenness has been increasing globally since at least 1981, when satellite technology enabled large-scale vegetation monitoring. The greening phenomenon, together with warming, sea-level rise and sea-ice decline, represents highly credible evidence of anthropogenic climate change. In this Review, we examine the detection of the greening signal, its causes and its consequences. Greening is pronounced over intensively farmed or afforested areas, such as in China and India, reflecting human activities. However, strong greening also occurs in biomes with low human footprint, such as the Arctic, where global change drivers play a dominant role. Vegetation models suggest that CO2 fertilization is the main driver of greening on the global scale, with other factors being notable at the regional scale. Modelling indicates that greening could mitigate global warming by increasing the carbon sink on land and altering biogeophysical processes, mainly evaporative cooling. Coupling high temporal and fine spatial resolution remote-sensing observations with ground measurements, increasing sampling in the tropics and Arctic, and modelling Earth systems in more detail will further our insights into the greening of Earth. Vegetation on Earth is increasing, potentially leading to a larger terrestrial carbon sink. In this Review, we discuss the occurrence of this global greening phenomenon, its drivers and how it might impact carbon cycling and land-atmosphere heat and water fluxes.
722 citations
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TL;DR: Stop using the worst-case scenario for climate warming as the most likely outcome — more-realistic baselines make for better policy.
Abstract: Stop using the worst-case scenario for climate warming as the most likely outcome — more-realistic baselines make for better policy. Stop using the worst-case scenario for climate warming as the most likely outcome — more-realistic baselines make for better policy.
498 citations
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TL;DR: The megadrought-like trajectory of 2000–2018 soil moisture was driven by natural variability superimposed on drying due to anthropogenic warming, which pushed an otherwise moderate drought onto a trajectory comparable to the worst SWNA megadroughts since 800 CE.
Abstract: Severe and persistent 21st-century drought in southwestern North America (SWNA) motivates comparisons to medieval megadroughts and questions about the role of anthropogenic climate change. We use hydrological modeling and new 1200-year tree-ring reconstructions of summer soil moisture to demonstrate that the 2000-2018 SWNA drought was the second driest 19-year period since 800 CE, exceeded only by a late-1500s megadrought. The megadrought-like trajectory of 2000-2018 soil moisture was driven by natural variability superimposed on drying due to anthropogenic warming. Anthropogenic trends in temperature, relative humidity, and precipitation estimated from 31 climate models account for 47% (model interquartiles of 35 to 105%) of the 2000-2018 drought severity, pushing an otherwise moderate drought onto a trajectory comparable to the worst SWNA megadroughts since 800 CE.
427 citations
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University of Edinburgh1, University of California2, University of Sheffield3, University of Virginia4, Aarhus University5, University of California, Davis6, University of Barcelona7, Northern Arizona University8, University of Alaska Fairbanks9, Netherlands Organisation for Scientific Research10, University of Oslo11, University of Bergen12, VU University Amsterdam13, University of Exeter14, Institute of Arctic and Alpine Research15, University of Lapland16, Grand Valley State University17, University of Zurich18, Colgate University19, University of Oxford20, Open University21, Umeå University22, University of Stirling23, University of Tromsø24, Lund University25, University of Alaska Anchorage26, University of Texas at El Paso27, University of Greifswald28, University of Aberdeen29, Swiss Federal Institute for Forest, Snow and Landscape Research30
TL;DR: In this paper, a consensus is emerging that the underlying causes and future dynamics of so-called Arctic greening and browning trends are more complex, variable and inherently scale-dependent than previously thought.
Abstract: As the Arctic warms, vegetation is responding, and satellite measures indicate widespread greening at high latitudes. This ‘greening of the Arctic’ is among the world’s most important large-scale ecological responses to global climate change. However, a consensus is emerging that the underlying causes and future dynamics of so-called Arctic greening and browning trends are more complex, variable and inherently scale-dependent than previously thought. Here we summarize the complexities of observing and interpreting high-latitude greening to identify priorities for future research. Incorporating satellite and proximal remote sensing with in-situ data, while accounting for uncertainties and scale issues, will advance the study of past, present and future Arctic vegetation change.
407 citations
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TL;DR: An intensification of extreme precipitation and flood events over all climate regions which increases as water availability increases from wet to dry regions and spatial and seasonal water availability becomes stronger as events become less extreme.
Abstract: The hydrological cycle is expected to intensify with global warming, which likely increases the intensity of extreme precipitation events and the risk of flooding. The changes, however, often differ from the theorized expectation of increases in water-holding capacity of the atmosphere in the warmer conditions, especially when water availability is limited. Here, the relationships of changes in extreme precipitation and flood intensities for the end of the twenty-first century with spatial and seasonal water availability are quantified. Results show an intensification of extreme precipitation and flood events over all climate regions which increases as water availability increases from wet to dry regions. Similarly, there is an increase in the intensification of extreme precipitation and flood with the seasonal cycle of water availability. The connection between extreme precipitation and flood intensity changes and spatial and seasonal water availability becomes stronger as events become less extreme.
400 citations
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TL;DR: This study constructs the most up-to-date CO2 emission inventories for China and its 30 provinces, as well as their energy inventories, for the years 2016 and 2017 and provides key updates and supplements to the previous emission dataset for 1997–2015.
Abstract: Despite China's emissions having plateaued in 2013, it is still the world's leading energy consumer and CO2 emitter, accounting for approximately 30% of global emissions. Detailed CO2 emission inventories by energy and sector have great significance to China's carbon policies as well as to achieving global climate change mitigation targets. This study constructs the most up-to-date CO2 emission inventories for China and its 30 provinces, as well as their energy inventories for the years 2016 and 2017. The newly compiled inventories provide key updates and supplements to our previous emission dataset for 1997-2015. Emissions are calculated based on IPCC (Intergovernmental Panel on Climate Change) administrative territorial scope that covers all anthropogenic emissions generated within an administrative boundary due to energy consumption (i.e. energy-related emissions from 17 fossil fuel types) and industrial production (i.e. process-related emissions from cement production). The inventories are constructed for 47 economic sectors consistent with the national economic accounting system. The data can be used as inputs to climate and integrated assessment models and for analysis of emission patterns of China and its regions.
397 citations
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TL;DR: In this paper, the main strategies for climate change abatement, namely conventional mitigation, negative emissions and radiative forcing geoengineering, are reviewed, and it is evident that conventional mitigation efforts alone are not sufficient to meet the targets stipulated by the Paris agreement; therefore, the utilization of alternative routes appears inevitable.
Abstract: Climate change is defined as the shift in climate patterns mainly caused by greenhouse gas emissions from natural systems and human activities. So far, anthropogenic activities have caused about 1.0 °C of global warming above the pre-industrial level and this is likely to reach 1.5 °C between 2030 and 2052 if the current emission rates persist. In 2018, the world encountered 315 cases of natural disasters which are mainly related to the climate. Approximately 68.5 million people were affected, and economic losses amounted to $131.7 billion, of which storms, floods, wildfires and droughts accounted for approximately 93%. Economic losses attributed to wildfires in 2018 alone are almost equal to the collective losses from wildfires incurred over the past decade, which is quite alarming. Furthermore, food, water, health, ecosystem, human habitat and infrastructure have been identified as the most vulnerable sectors under climate attack. In 2015, the Paris agreement was introduced with the main objective of limiting global temperature increase to 2 °C by 2100 and pursuing efforts to limit the increase to 1.5 °C. This article reviews the main strategies for climate change abatement, namely conventional mitigation, negative emissions and radiative forcing geoengineering. Conventional mitigation technologies focus on reducing fossil-based CO2 emissions. Negative emissions technologies are aiming to capture and sequester atmospheric carbon to reduce carbon dioxide levels. Finally, geoengineering techniques of radiative forcing alter the earth’s radiative energy budget to stabilize or reduce global temperatures. It is evident that conventional mitigation efforts alone are not sufficient to meet the targets stipulated by the Paris agreement; therefore, the utilization of alternative routes appears inevitable. While various technologies presented may still be at an early stage of development, biogenic-based sequestration techniques are to a certain extent mature and can be deployed immediately.
391 citations
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TL;DR: The empirical study shows that for BRICS countries, unlike coal consumption, coal rents have a significant but negative impact on CO2 emissions, and for policymakers it is vital to reinforce the use of stringent regulations as these economies opens up to more use of coal energy.
344 citations
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18 Aug 2020
TL;DR: In this paper, the authors describe recent global and regional trends in fire activity and examine projections for fire regimes in the near future, concluding that the economic and environmental impacts of vegetation fires will worsen as a result of anthropogenic climate change.
Abstract: Vegetation fires are an essential component of the Earth system but can also cause substantial economic losses, severe air pollution, human mortality and environmental damage. Contemporary fire regimes are increasingly impacted by human activities and climate change, but, owing to the complex fire–human–climate interactions and incomplete historical or long-term datasets, it is difficult to detect and project fire-regime trajectories. In this Review, we describe recent global and regional trends in fire activity and examine projections for fire regimes in the near future. Although there are large uncertainties, it is likely that the economic and environmental impacts of vegetation fires will worsen as a result of anthropogenic climate change. These effects will be particularly prominent in flammable forests in populated temperate zones, the sparsely inhabited flammable boreal zone and fire-sensitive tropical rainforests, and will contribute to greenhouse gas emissions. The impacts of increased fire activity can be mitigated through effective stewardship of fire regimes, which should be achieved through evidence-based fire management that incorporates indigenous and local knowledge, combined with planning and design of natural and urban landscapes. Increasing transdisciplinary research is needed to fully understand how Anthropocene fire regimes are changing and how humans must adapt.
338 citations
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TL;DR: Using annual projections of temperature and precipitation across the ranges of more than 30,000 marine and terrestrial species to estimate when species will be exposed to potentially harmful climate conditions reveals that disruption of ecological assemblages as a result of climate change will be abrupt and could start as early as the current decade.
Abstract: As anthropogenic climate change continues the risks to biodiversity will increase over time, with future projections indicating that a potentially catastrophic loss of global biodiversity is on the horizon1–3. However, our understanding of when and how abruptly this climate-driven disruption of biodiversity will occur is limited because biodiversity forecasts typically focus on individual snapshots of the future. Here we use annual projections (from 1850 to 2100) of temperature and precipitation across the ranges of more than 30,000 marine and terrestrial species to estimate the timing of their exposure to potentially dangerous climate conditions. We project that future disruption of ecological assemblages as a result of climate change will be abrupt, because within any given ecological assemblage the exposure of most species to climate conditions beyond their realized niche limits occurs almost simultaneously. Under a high-emissions scenario (representative concentration pathway (RCP) 8.5), such abrupt exposure events begin before 2030 in tropical oceans and spread to tropical forests and higher latitudes by 2050. If global warming is kept below 2 °C, less than 2% of assemblages globally are projected to undergo abrupt exposure events of more than 20% of their constituent species; however, the risk accelerates with the magnitude of warming, threatening 15% of assemblages at 4 °C, with similar levels of risk in protected and unprotected areas. These results highlight the impending risk of sudden and severe biodiversity losses from climate change and provide a framework for predicting both when and where these events may occur. Using annual projections of temperature and precipitation to estimate when species will be exposed to potentially harmful climate conditions reveals that disruption of ecological assemblages as a result of climate change will be abrupt and could start as early as the current decade.
324 citations
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Swiss Federal Institute for Forest, Snow and Landscape Research1, University of Cambridge2, Ghent University3, University of Picardie Jules Verne4, University of Jena5, Academy of Sciences of the Czech Republic6, University of West Hungary7, Swedish University of Agricultural Sciences8, Research Institute for Nature and Forest9, Environment Agency10, Rzeszów University11, University of Potsdam12, University of Warsaw13, Czech University of Life Sciences Prague14, University of Wrocław15, University of Ljubljana16, University of Pécs17, University of Agriculture, Faisalabad18, University of Göttingen19, Eötvös Loránd University20, American Museum of Natural History21
TL;DR: It is shown that thermophilization and the climatic lag in forest plant communities are primarily controlled by microclimate, and increasing tree canopy cover reduces warming rates inside forests, but loss of canopy cover leads to increased local heat that exacerbates the disequilibrium between community responses and climate change.
Abstract: Climate warming is causing a shift in biological communities in favor of warm-affinity species (i.e., thermophilization). Species responses often lag behind climate warming, but the reasons for such lags remain largely unknown. Here, we analyzed multidecadal understory microclimate dynamics in European forests and show that thermophilization and the climatic lag in forest plant communities are primarily controlled by microclimate. Increasing tree canopy cover reduces warming rates inside forests, but loss of canopy cover leads to increased local heat that exacerbates the disequilibrium between community responses and climate change. Reciprocal effects between plants and microclimates are key to understanding the response of forest biodiversity and functioning to climate and land-use changes.
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TL;DR: A failure to recognize the factors behind continued emissions growth could limit the world's ability to shift to a pathway consistent with 1.5 °C or 2 °C of global warming as mentioned in this paper.
Abstract: A failure to recognize the factors behind continued emissions growth could limit the world’s ability to shift to a pathway consistent with 1.5 °C or 2 °C of global warming. Continued support for low-carbon technologies needs to be combined with policies directed at phasing out the use of fossil fuels.
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TL;DR: Analysis of stage-specific thermal tolerance metrics for 694 marine and freshwater fish species shows that spawning adults and embryos consistently have narrower tolerance ranges than larvae and nonreproductive adults and are most vulnerable to climate warming.
Abstract: Species’ vulnerability to climate change depends on the most temperature-sensitive life stages, but for major animal groups such as fish, life cycle bottlenecks are often not clearly defined. We used observational, experimental, and phylogenetic data to assess stage-specific thermal tolerance metrics for 694 marine and freshwater fish species from all climate zones. Our analysis shows that spawning adults and embryos consistently have narrower tolerance ranges than larvae and nonreproductive adults and are most vulnerable to climate warming. The sequence of stage-specific thermal tolerance corresponds with the oxygen-limitation hypothesis, suggesting a mechanistic link between ontogenetic changes in cardiorespiratory (aerobic) capacity and tolerance to temperature extremes. A logarithmic inverse correlation between the temperature dependence of physiological rates (development and oxygen consumption) and thermal tolerance range is proposed to reflect a fundamental, energetic trade-off in thermal adaptation. Scenario-based climate projections considering the most critical life stages (spawners and embryos) clearly identify the temperature requirements for reproduction as a critical bottleneck in the life cycle of fish. By 2100, depending on the Shared Socioeconomic Pathway (SSP) scenario followed, the percentages of species potentially affected by water temperatures exceeding their tolerance limit for reproduction range from ~10% (SSP 1–1.9) to ~60% (SSP 5–8.5). Efforts to meet ambitious climate targets (SSP 1–1.9) could therefore benefit many fish species and people who depend on healthy fish stocks.
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TL;DR: Cloud feedbacks and cloud-aerosol interactions are the most likely contributors to the high values and increased range of ECS in CMIP6.
Abstract: For the current generation of earth system models participating in the Coupled Model Intercomparison Project Phase 6 (CMIP6), the range of equilibrium climate sensitivity (ECS, a hypothetical value of global warming at equilibrium for a doubling of CO2) is 18°C to 56°C, the largest of any generation of models dating to the 1990s Meanwhile, the range of transient climate response (TCR, the surface temperature warming around the time of CO2 doubling in a 1% per year CO2 increase simulation) for the CMIP6 models of 17°C (13°C to 30°C) is only slightly larger than for the CMIP3 and CMIP5 models Here we review and synthesize the latest developments in ECS and TCR values in CMIP, compile possible reasons for the current values as supplied by the modeling groups, and highlight future directions Cloud feedbacks and cloud-aerosol interactions are the most likely contributors to the high values and increased range of ECS in CMIP6
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Stanford University1, Stockholm University2, Texas A&M University3, University of Exeter4, United States Geological Survey5, University of California, Los Angeles6, University of Jyväskylä7, University of Alberta8, University of Toronto9, Umeå University10, University of New Hampshire11, University of Guelph12, University of Colorado Boulder13, Université de Montréal14, Lehigh University15, Northeast Normal University16
TL;DR: This study compiles over 7,000 field observations to present a data-driven map of northern peatlands and their carbon and nitrogen stocks, and uses machine-learning techniques with extensive peat core data to create observation-based maps ofNorthern peatland C and N stocks and to assess their response to warming and permafrost thaw.
Abstract: Northern peatlands have accumulated large stocks of organic carbon (C) and nitrogen (N), but their spatial distribution and vulnerability to climate warming remain uncertain. Here, we used machine-learning techniques with extensive peat core data (n > 7,000) to create observation-based maps of northern peatland C and N stocks, and to assess their response to warming and permafrost thaw. We estimate that northern peatlands cover 3.7 ± 0.5 million km2 and store 415 ± 150 Pg C and 10 ± 7 Pg N. Nearly half of the peatland area and peat C stocks are permafrost affected. Using modeled global warming stabilization scenarios (from 1.5 to 6 °C warming), we project that the current sink of atmospheric C (0.10 ± 0.02 Pg C⋅y-1) in northern peatlands will shift to a C source as 0.8 to 1.9 million km2 of permafrost-affected peatlands thaw. The projected thaw would cause peatland greenhouse gas emissions equal to ∼1% of anthropogenic radiative forcing in this century. The main forcing is from methane emissions (0.7 to 3 Pg cumulative CH4-C) with smaller carbon dioxide forcing (1 to 2 Pg CO2-C) and minor nitrous oxide losses. We project that initial CO2-C losses reverse after ∼200 y, as warming strengthens peatland C-sinks. We project substantial, but highly uncertain, additional losses of peat into fluvial systems of 10 to 30 Pg C and 0.4 to 0.9 Pg N. The combined gaseous and fluvial peatland C loss estimated here adds 30 to 50% onto previous estimates of permafrost-thaw C losses, with southern permafrost regions being the most vulnerable.
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TL;DR: It is shown that projected future warming is correlated with the simulated warming trend during recent decades across CMIP5 and CMIP6 models, enabling us to constrain future warming based on consistency with the observed warming.
Abstract: Future global warming estimates have been similar across past assessments, but several climate models of the latest Sixth Coupled Model Intercomparison Project (CMIP6) simulate much stronger warming, apparently inconsistent with past assessments. Here, we show that projected future warming is correlated with the simulated warming trend during recent decades across CMIP5 and CMIP6 models, enabling us to constrain future warming based on consistency with the observed warming. These findings carry important policy-relevant implications: The observationally constrained CMIP6 median warming in high emissions and ambitious mitigation scenarios is over 16 and 14% lower by 2050 compared to the raw CMIP6 median, respectively, and over 14 and 8% lower by 2090, relative to 1995–2014. Observationally constrained CMIP6 warming is consistent with previous assessments based on CMIP5 models, and in an ambitious mitigation scenario, the likely range is consistent with reaching the Paris Agreement target.
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TL;DR: In this article, the authors quantify observed changes in the occurrence and magnitude of meteorological factors that enable extreme autumn wildfires in California, and use climate model simulations to ascertain whether these changes are attributable to human-caused climate change.
Abstract: California has experienced devastating autumn wildfires in recent years. These autumn wildfires have coincided with extreme fire weather conditions during periods of strong offshore winds coincident with unusually dry vegetation enabled by anomalously warm conditions and late onset of autumn precipitation. In this study, we quantify observed changes in the occurrence and magnitude of meteorological factors that enable extreme autumn wildfires in California, and use climate model simulations to ascertain whether these changes are attributable to human-caused climate change. We show that state-wide increases in autumn temperature (~1 ˚C) and decreases in autumn precipitation (~30%) over the past four decades have contributed to increases in aggregate fire weather indices (+20%). As a result, the observed frequency of autumn days with extreme (95th percentile) fire weather – which we show are preferentially associated with extreme autumn wildfires – has more than doubled in California since the early 1980s. We further find an increase in the climate model-estimated probability of these extreme autumn conditions since ~1950, including a long-term trend toward increased same-season co-occurrence of extreme fire weather conditions in northern and southern California. Our climate model analyses suggest that continued climate change will further amplify the number of days with extreme fire weather by the end of this century, though a pathway consistent with the UN Paris commitments would substantially curb that increase. Given the acute societal impacts of extreme autumn wildfires in recent years, our findings have critical relevance for ongoing efforts to manage wildfire risks in California and other regions.
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TL;DR: Novel perspectives on how ecosystems respond to climate change, how ecosystem resilience can be enhanced and how ecosystems can assist in addressing the challenge of a changing climate are explored.
Abstract: The rapid anthropogenic climate change that is being experienced in the early twenty-first century is intimately entwined with the health and functioning of the biosphere. Climate change is impacting ecosystems through changes in mean conditions and in climate variability, coupled with other associated changes such as increased ocean acidification and atmospheric carbon dioxide concentrations. It also interacts with other pressures on ecosystems, including degradation, defaunation and fragmentation. There is a need to understand the ecological dynamics of these climate impacts, to identify hotspots of vulnerability and resilience and to identify management interventions that may assist biosphere resilience to climate change. At the same time, ecosystems can also assist in the mitigation of, and adaptation to, climate change. The mechanisms, potential and limits of such nature-based solutions to climate change need to be explored and quantified. This paper introduces a thematic issue dedicated to the interaction between climate change and the biosphere. It explores novel perspectives on how ecosystems respond to climate change, how ecosystem resilience can be enhanced and how ecosystems can assist in addressing the challenge of a changing climate. It draws on a Royal Society-National Academy of Sciences Forum held in Washington DC in November 2018, where these themes and issues were discussed. We conclude by identifying some priorities for academic research and practical implementation, in order to maximize the potential for maintaining a diverse, resilient and well-functioning biosphere under the challenging conditions of the twenty-first century. This article is part of the theme issue 'Climate change and ecosystems: threats, opportunities and solutions'.
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University of Paris1, École Normale Supérieure2, Hobart Corporation3, Fisheries and Oceans Canada4, Geophysical Fluid Dynamics Laboratory5, Université Paris-Saclay6, Max Planck Society7, University of Tasmania8, University of Colorado Boulder9, National Oceanography Centre10, University of Toulouse11, Bjerknes Centre for Climate Research12, University of Liverpool13, Los Alamos National Laboratory14, Japan Meteorological Agency15, Japan Agency for Marine-Earth Science and Technology16
TL;DR: In this paper, the authors assess projections of these drivers of environmental change over the twenty-first century from Earth system models (ESMs) participating in the Coupled Model Intercomparison Project Phase 6 (CMIP6) that were forced under the CMIP6 Shared Socioeconomic Pathways (SSPs).
Abstract: . Anthropogenic climate change is projected to lead to ocean warming, acidification, deoxygenation,
reductions in near-surface nutrients, and changes to primary production, all of which are expected
to affect marine ecosystems. Here we assess projections of these drivers of environmental change
over the twenty-first century from Earth system models (ESMs) participating in the Coupled Model
Intercomparison Project Phase 6 (CMIP6) that were forced under the CMIP6 Shared Socioeconomic
Pathways (SSPs). Projections are compared to those from the previous generation (CMIP5) forced
under the Representative Concentration Pathways (RCPs). A total of 10 CMIP5 and 13 CMIP6 models are used in
the two multi-model ensembles. Under the high-emission scenario SSP5-8.5, the multi-model global
mean change (2080–2099 mean values relative to 1870–1899) ± the inter-model SD in sea
surface temperature, surface pH, subsurface (100–600 m ) oxygen concentration, euphotic
(0–100 m ) nitrate concentration, and depth-integrated primary production is
+ 3.47 ± 0.78 ∘C , - 0.44 ± 0.005 , - 13.27 ± 5.28 ,
- 1.06 ± 0.45 mmol m−3 and - 2.99 ± 9.11 %, respectively. Under the
low-emission, high-mitigation scenario SSP1-2.6, the corresponding global changes are
+ 1.42 ± 0.32 ∘C , - 0.16 ± 0.002 , - 6.36 ± 2.92 ,
- 0.52 ± 0.23 mmol m−3 , and - 0.56 ± 4.12 %. Projected exposure of the marine
ecosystem to these drivers of ocean change depends largely on the extent of future emissions,
consistent with previous studies. The ESMs in CMIP6 generally project greater warming,
acidification, deoxygenation, and nitrate reductions but lesser primary production declines than
those from CMIP5 under comparable radiative forcing. The increased projected ocean warming results
from a general increase in the climate sensitivity of CMIP6 models relative to those of
CMIP5. This enhanced warming increases upper-ocean stratification in CMIP6 projections, which
contributes to greater reductions in upper-ocean nitrate and subsurface oxygen ventilation. The
greater surface acidification in CMIP6 is primarily a consequence of the SSPs having higher
associated atmospheric CO2 concentrations than their RCP analogues for the same
radiative forcing. We find no consistent reduction in inter-model uncertainties, and even an
increase in net primary
production inter-model uncertainties in CMIP6, as compared to CMIP5.
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TL;DR: The authors found that people revise their beliefs about climate change upward when experiencing warmer than usual temperatures in their area and that stocks of carbon-intensive firms underperform firms with low carbon emissions in abnormally warm weather.
Abstract: We find that people revise their beliefs about climate change upward when experiencing warmer than usual temperatures in their area. Using international data, we show that attention to climate change, as proxied by Google search volume, increases when the local temperature is abnormally high. In financial markets, stocks of carbon-intensive firms underperform firms with low carbon emissions in abnormally warm weather. Retail investors (not institutional investors) sell carbon-intensive firms in such weather, and return patterns are unlikely to be driven by changes in fundamentals. Our study sheds light on peoples’ collective beliefs and actions about global warming.
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Ontario Ministry of Natural Resources1, International Institute of Minnesota2, Chinese Ministry of Education3, University of Toronto4, Centre national de la recherche scientifique5, Spanish National Research Council6, University of Antwerp7, Carnegie Institution for Science8, University of California, Merced9, University of Exeter10, University of Arizona11, Sun Yat-sen University12, National Center for Atmospheric Research13, Forest Research Institute14, Oeschger Centre for Climate Change Research15, Goddard Space Flight Center16, Fudan University17, University of Maryland, College Park18, Chinese Academy of Sciences19, Auburn University20, University of Illinois at Urbana–Champaign21, Commonwealth Scientific and Industrial Research Organisation22, University of Augsburg23
TL;DR: Global CFE has declined across most terrestrial regions of the globe from 1982 to 2015, correlating well with changing nutrient concentrations and availability of soil water, and implies a weakening negative feedback on the climatic system and increased societal dependence on future strategies to mitigate climate warming.
Abstract: The enhanced vegetation productivity driven by increased concentrations of carbon dioxide (CO2) [i.e., the CO2 fertilization effect (CFE)] sustains an important negative feedback on climate warming, but the temporal dynamics of CFE remain unclear. Using multiple long-term satellite- and ground-based datasets, we showed that global CFE has declined across most terrestrial regions of the globe from 1982 to 2015, correlating well with changing nutrient concentrations and availability of soil water. Current carbon cycle models also demonstrate a declining CFE trend, albeit one substantially weaker than that from the global observations. This declining trend in the forcing of terrestrial carbon sinks by increasing amounts of atmospheric CO2 implies a weakening negative feedback on the climatic system and increased societal dependence on future strategies to mitigate climate warming.
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TL;DR: Harmful Algae's first Special Issue on Climate Change and Harmful Algal Blooms is published, providing clear evidence that the field of HABs and climate change has matured and has, perhaps, reached a first plateau of certainty.
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TL;DR: The MIROC-ES2L model as mentioned in this paper uses a state-of-the-art climate model as the physical core and embeds a terrestrial biogeochemical component with explicit carbon-nitrogen interaction to account for soil nutrient control and plant growth.
Abstract: . This article describes the new Earth system model (ESM), the Model for
Interdisciplinary Research on Climate, Earth System version 2 for Long-term
simulations (MIROC-ES2L), using a state-of-the-art climate model as the
physical core. This model embeds a terrestrial biogeochemical component with
explicit carbon–nitrogen interaction to account for soil nutrient control
on plant growth and the land carbon sink. The model's ocean biogeochemical
component is largely updated to simulate the biogeochemical cycles of carbon,
nitrogen, phosphorus, iron, and oxygen such that oceanic primary
productivity can be controlled by multiple nutrient limitations. The ocean
nitrogen cycle is coupled with the land component via river discharge
processes, and external inputs of iron from pyrogenic and lithogenic sources
are considered. Comparison of a historical simulation with observation
studies showed that the model could reproduce the transient global climate
change and carbon cycle as well as the observed large-scale spatial patterns
of the land carbon cycle and upper-ocean biogeochemistry. The model
demonstrated historical human perturbation of the nitrogen cycle through
land use and agriculture and simulated the resultant impact on the
terrestrial carbon cycle. Sensitivity analyses under preindustrial
conditions revealed that the simulated ocean biogeochemistry could be
altered regionally (and substantially) by nutrient input from the atmosphere
and rivers. Based on an idealized experiment in which CO2 was
prescribed to increase at a rate of 1 % yr −1 , the transient climate
response (TCR) is estimated to be 1.5 K, i.e., approximately 70 % of that from
our previous ESM used in the Coupled Model Intercomparison Project Phase 5
(CMIP5). The cumulative airborne fraction (AF) is also reduced by 15 %
because of the intensified land carbon sink, which results in an airborne
fraction close to the multimodel mean of the CMIP5 ESMs. The transient
climate response to cumulative carbon emissions (TCRE) is 1.3 K EgC −1 ,
i.e., slightly smaller than the average of the CMIP5 ESMs, which suggests
that “optimistic” future climate projections will be made by the model.
This model and the simulation results contribute to CMIP6. The MIROC-ES2L
could further improve our understanding of climate–biogeochemical
interaction mechanisms, projections of future environmental changes, and
exploration of our future options regarding sustainable development by
evolving the processes of climate, biogeochemistry, and human activities in
a holistic and interactive manner.
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The Nature Conservancy1, Smithsonian Environmental Research Center2, World Resources Institute3, Smithsonian Tropical Research Institute4, Smithsonian Conservation Biology Institute5, State University of New York College of Environmental Science and Forestry6, University of Connecticut7, University of the Sunshine Coast8, ETH Zurich9, James Madison University10, University of California, Santa Cruz11, Woods Hole Research Center12, University of Oxford13, University of Exeter14, Aberystwyth University15, Environmental Change Institute16, Université du Québec à Montréal17, Commonwealth Scientific and Industrial Research Organisation18, Jet Propulsion Laboratory19, University of Edinburgh20, Yale University21, Conservation International22
TL;DR: A global, one-kilometre-resolution map of potential aboveground carbon accumulation rates for the first 30 years of natural forest regrowth is presented, indicating that default rates from the Intergovernmental Panel on Climate Change (IPCC) may be underestimated and maximum climate mitigation potential from natural forest Regrowth is 11 per cent lower than previously reported.
Abstract: To constrain global warming, we must strongly curtail greenhouse gas emissions and capture excess atmospheric carbon dioxide1,2. Regrowing natural forests is a prominent strategy for capturing additional carbon3, but accurate assessments of its potential are limited by uncertainty and variability in carbon accumulation rates2,3. To assess why and where rates differ, here we compile 13,112 georeferenced measurements of carbon accumulation. Climatic factors explain variation in rates better than land-use history, so we combine the field measurements with 66 environmental covariate layers to create a global, one-kilometre-resolution map of potential aboveground carbon accumulation rates for the first 30 years of natural forest regrowth. This map shows over 100-fold variation in rates across the globe, and indicates that default rates from the Intergovernmental Panel on Climate Change (IPCC)4,5 may underestimate aboveground carbon accumulation rates by 32 per cent on average and do not capture eight-fold variation within ecozones. Conversely, we conclude that maximum climate mitigation potential from natural forest regrowth is 11 per cent lower than previously reported3 owing to the use of overly high rates for the location of potential new forest. Although our data compilation includes more studies and sites than previous efforts, our results depend on data availability, which is concentrated in ten countries, and data quality, which varies across studies. However, the plots cover most of the environmental conditions across the areas for which we predicted carbon accumulation rates (except for northern Africa and northeast Asia). We therefore provide a robust and globally consistent tool for assessing natural forest regrowth as a climate mitigation strategy. A one-kilometre-resolution map of aboveground carbon accumulation rates of forest regrowth shows 100-fold variation across the globe, with rates 32% higher on average than IPCC estimates.
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01 Jan 2020TL;DR: In this article, the intricate relationship between CO2 emission, global warming, and climate change was explicitly explained, and CO2 mitigation strategies in selected industrial sectors such as power, cement, iron, and steel as well as the petrochemical industry were presented.
Abstract: This chapter discusses the concepts of CO2 emission, global warming, and climate change with an emphasis on their environmental impacts. Specifically, the chapter reviews different sources of atmospheric CO2 emissions and recent advances in the implementation of carbon capture and storage (CCS) technology to mitigate greenhouse gas emissions. In this chapter, the intricate relationship between CO2 emission, global warming, and climate change was explicitly explained, and CO2 mitigation strategies in selected industrial sectors such as power, cement, iron, and steel as well as the petrochemical industry were presented. An overview of process integration concepts for energy minimization in environmental sustainability studies was highlighted. The current state of research in this field was reviewed, while future prospects in the application of process synthesis techniques to decrease the high energy and material requirement during CO2 capture were suggested. Finally, CO2 emission trend since the beginning of the first industrial revolution was discussed alongside current international treaties, limitations, and forecasts about greenhouse gas emission.
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TL;DR: This map shows how wildfires across the globe are changing the landscape, including in California, where wildfires are increasingly common and projected to worsen with climate change.
Abstract: Wildfires, Global Climate Change, and Human Health Wildfires are increasingly common and projected to worsen with climate change. Health consequences include burns and mental health effects, as wel...
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TL;DR: In this article, the authors examined lake evolution, spatial patterns and driving mechanisms over the Tibetan Plateau, showing an overall lake growth in the north of the inner plateau against a reduction in the south.
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University of Denver1, Joint Global Change Research Institute2, Finnish Environment Institute3, University of Washington4, Stockholm Environment Institute5, Wageningen University and Research Centre6, Potsdam Institute for Climate Impact Research7, RAND Corporation8, International Institute for Applied Systems Analysis9, Utrecht University10, Netherlands Environmental Assessment Agency11, National Autonomous University of Mexico12, Ritsumeikan University13, German Development Institute14, Calcutta Institute of Engineering and Management15
TL;DR: It is concluded that the SSP–RCP scenario framework has been widely adopted across research communities and is largely meeting immediate needs, however, some mixed successes and a changing policy and research landscape present key challenges.
Abstract: Long-term global scenarios have underpinned research and assessment of global environmental change for four decades. Over the past ten years, the climate change research community has developed a scenario framework combining alternative futures of climate and society to facilitate integrated research and consistent assessment to inform policy. Here we assess how well this framework is working and what challenges it faces. We synthesize insights from scenario-based literature, community discussions and recent experience in assessments, concluding that the framework has been widely adopted across research communities and is largely meeting immediate needs. However, some mixed successes and a changing policy and research landscape present key challenges, and we recommend several new directions for the development and use of this framework.
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TL;DR: In this article, the authors compared the performance of models available in CMIP5 and CMIP6 consortium and their multi-model average (MMA) and found a significant improvement in model performance in capturing the spatiotemporal pattern of monsoon over Indian landmass, especially in the Western Ghats and North-east foothills of Himalayas.
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TL;DR: It is demonstrated that the occurrence of the 2018–2019 (consecutive) summer drought is unprecedented in the last 250 years, and its combined impact on the growing season vegetation activities is stronger compared to the 2003 European drought.
Abstract: Since the spring 2018, a large part of Europe has been in the midst of a record-setting drought. Using long-term observations, we demonstrate that the occurrence of the 2018–2019 (consecutive) summer drought is unprecedented in the last 250 years, and its combined impact on the growing season vegetation activities is stronger compared to the 2003 European drought. Using a suite of climate model simulation outputs, we underpin the role of anthropogenic warming on exacerbating the future risk of such a consecutive drought event. Under the highest Representative Concentration Pathway, (RCP 8.5), we notice a seven-fold increase in the occurrence of the consecutive droughts, with additional 40 ($$\pm \, 5$$) million ha of cultivated areas being affected by such droughts, during the second half of the twenty-first century. The occurrence is significantly reduced under low and medium scenarios (RCP 2.6 and RCP 4.5), suggesting that an effective mitigation strategy could aid in reducing the risk of future consecutive droughts.