The #human #imperative of stabilizing #global #climatechange at 1.5°C (Science, abstract)

[Source: Science, full page: (LINK). Abstract, edited.]

The human imperative of stabilizing global climate change at 1.5°C

O. Hoegh-Guldberg1,2,*, D. Jacob3, M. Taylor4, T. Guillén Bolaños3, M. Bindi5, S. Brown6,7, I. A. Camilloni8, A. Diedhiou9, R. Djalante10,11, K. Ebi12, F. Engelbrecht13, J. Guiot14, Y. Hijioka15, S. Mehrotra16, C. W. Hope17, A. J. Payne18, H.-O. Pörtner19, S. I. Seneviratne20, A. Thomas21,22, R. Warren23, G. Zhou24

1 Global Change Institute, University of Queensland, St. Lucia, QLD 4072, Australia. 2 School of Biological Sciences, University of Queensland, St. Lucia, QLD 4072, Australia. 3 Climate Service Center Germany (GERICS), Helmholtz-Zentrum Geesthacht, Hamburg, Germany. 4 Department of Physics, University of the West Indies, Kingston, Jamaica. 5 Department of Agriculture, Food, Environment and Forestry (DAGRI), University of Florence, 50144 Firenze, Italy. 6 Faculty of Engineering and Physical Sciences, University of Southampton, Boldrewood Innovation Campus, Southampton SO16 7QF, UK. 7 Department of Life and Environmental Sciences, Faculty of Science and Technology, Bournemouth University, Fern Barrow, Poole, Dorset BH12 5BB, UK. 8 Centro de Investigaciones del Mar y la Atmósfera (UBA-CONICET), UMI-IFAECI/CNRS, and Departamento de Ciencias de la Atmósfera y los Océanos (FCEN), University of Buenos Aires, Buenos Aires, Argentina. 9 Université Grenoble Alpes, French National Research Institute for Sustainable Development (IRD), CNRS, Grenoble INP, IGE, F-38000 Grenoble, France. 10 United Nations University–Institute for the Advanced Study of Sustainability (UNU-IAS), Tokyo, Japan. 11 Halu Oleo University, Kendari, South East Sulawesi, Indonesia. 12 Center for Health and the Global Environment, University of Washington, Seattle, WA, USA. 13 Global Change Institute, University of the Witwatersrand, Johannesburg 2193, South Africa. 14 Aix Marseille University, CNRS, IRD, INRA, Collège de France, CEREGE, Aix-en-Provence, France. 15 Center for Climate Change Adaptation, National Institute for Environmental Studies, Onogawa, Tsukuba, Ibaraki 305-8506, Japan. 16 World Bank, Washington, DC, USA. 17 Cambridge Judge Business School, University of Cambridge, Cambridge, UK. 18 University of Bristol, Bristol, UK. 19 Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany. 20 Institute for Atmospheric and Climate Science, ETH Zurich, Zurich, Switzerland. 21 Climate Analytics, 10961 Berlin, Germany. 22 Environmental and Life Sciences, University of the Bahamas, Nassau 76905, Bahamas. 23 Tyndall Centre for Climate Change Research and School of Environmental Sciences, University of East Anglia, Norwich NR4 7TJ, UK. 24 State Key Laboratory of Severe Weather, Chinese Academy of Meteorological Sciences, Beijing 100081, China.

*Corresponding author. Email: oveh@uq.edu.au

Science  20 Sep 2019: Vol. 365, Issue 6459, eaaw6974 / DOI: 10.1126/science.aaw6974

 

The need to stabilize global climate

Climate change will be the greatest threat to humanity and global ecosystems in the coming years, and there is a pressing need to understand and communicate the impacts of warming, across the perspectives of the natural and social sciences. Hoegh-Guldberg et al. review the climate change–impact literature, expanding on the recent report of the Intergovernmental Panel on Climate Change. They provide evidence of the impacts of warming at 1°, 1.5°, and 2°C—and higher—for the physical system, ecosystems, agriculture, and human livelihoods. The benefits of limiting climate change to no more than 1.5°C above preindustrial levels would outweigh the costs.

Science, this issue p. eaaw6974

 

Structured Abstract

BACKGROUND

The United Nations Framework Convention on Climate Change (UNFCCC) was established in 1992 to pursue the “stabilization of greenhouse gas concentrations at a level that would prevent dangerous anthropogenic interferences with the climate system.” Since 1992, five major climate change assessment cycles have been completed by the UN Intergovernmental Panel on Climate Change (IPCC). These reports identified rapidly growing climate-related impacts and risks, including more intense storms, collapsing ecosystems, and record heatwaves, among many others. Once thought to be tolerable, increases in global mean surface temperature (GMST) of 2.0°C or higher than the pre-industrial period look increasingly unmanageable and hence dangerous to natural and human systems.

The Paris Climate Agreement is the most recent attempt to establish international cooperation over climate change. This agreement, ratified or acceded to by 185 countries, was designed to bring nations together voluntarily to take ambitious action on mitigating climate change, while also developing adaptation options and strategies as well as guaranteeing the means of implementation (e.g., climate finance). The Agreement is aimed at “holding the increase in the global average temperature to well below 2.0°C above pre-industrial levels and pursuing efforts to limit the temperature increase to 1.5°C above pre-industrial levels, recognizing that this would significantly reduce the risks and impacts of climate change.” Many unanswered questions regarding a 1.5°C target surround the feasibility, costs, and inherent risks to natural and human systems. Consequently, countries invited the IPCC to prepare a Special Report on “the impacts of global warming of 1.5°C above pre-industrial levels and related global greenhouse gas emission pathways, in the context of strengthening the global response to the threat of climate change, sustainable development, and efforts to eradicate poverty.” The Special Report was completed and approved by the 48th Session of the IPCC in October 2018.

ADVANCES

Multiple lines of evidence indicate that the next 0.5°C above today (which will take GMST from 1.0°C to 1.5°C above the pre-industrial period) will involve greater risks per unit temperature than those seen in the last 0.5°C increase. This principle of “accelerating risk” is also likely to drive proportionally and possibly exponentially higher risk levels in the transition from 1.5°C to 2.0°C above the pre-industrial period. We argue that this is a consequence of impacts accelerating as a function of distance from the optimal temperature for an organism or an ecosystem process. Coral reefs, for example, often appear healthy right up until the onset of mass coral bleaching and mortality, which can then destroy a reef within a few months. This also explains the observation of “tipping points” where the condition of a group of organisms or an ecosystem can appear “healthy” right up to the point of collapse, suggesting caution in extrapolating from measures of ecosystem condition to predict the future. Information of this nature needs to be combined with an appreciation of organisms’ distance from their optimal temperature.

Finally, we explore elements of the costs and benefits associated with acting in response to climate change, and come to the preliminary conclusion that restraining average global temperature to 1.5°C above the pre-industrial period would be much less costly than the damage due to inaction on global climate change.

OUTLOOK

As an IPCC expert group, we were asked to assess the impact of recent climate change (1.0°C, 2017) and the likely impact over the next 0.5° to 1.0°C of additional global warming. At the beginning of this exercise, many of us were concerned that the task would be hindered by a lack of expert literature available for 1.5°C and 2.0°C warmer worlds. Although this was the case at the time of the Paris Agreement, it has not been our experience 4 years later. With an accelerating amount of peer-reviewed scientific literature since the IPCC Special Report Global Warming of 1.5°C, it is very clear that there is an even more compelling case for deepening commitment and actions for stabilizing GMST at 1.5°C above the pre-industrial period.

 

Abstract

Increased concentrations of atmospheric greenhouse gases have led to a global mean surface temperature 1.0°C higher than during the pre-industrial period. We expand on the recent IPCC Special Report on global warming of 1.5°C and review the additional risks associated with higher levels of warming, each having major implications for multiple geographies, climates, and ecosystems. Limiting warming to 1.5°C rather than 2.0°C would be required to maintain substantial proportions of ecosystems and would have clear benefits for human health and economies. These conclusions are relevant for people everywhere, particularly in low- and middle-income countries, where the escalation of climate-related risks may prevent the achievement of the United Nations Sustainable Development Goals.

Keywords: Climate Change; Global Warming; International cooperation.

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Multidecadal #observations of the #Antarctic #icesheet from restored analog #radar #records (Proc Natl Acad Sci USA, abstract)

[Source: Proceedings of the National Academy of Sciences of the United States of America, full page: (LINK). Abstract, edited.]

Multidecadal observations of the Antarctic ice sheet from restored analog radar records

Dustin M. Schroeder, Julian A. Dowdeswell, Martin J. Siegert, Robert G. Bingham, Winnie Chu, Emma J. MacKie, Matthew R. Siegfried, Katherine I. Vega, John R. Emmons, and Keith Winstein

PNAS first published September 3, 2019 / DOI: https://doi.org/10.1073/pnas.1821646116

Edited by Eric Rignot, University of California, Irvine, CA, and approved August 8, 2019 (received for review December 19, 2018)

 

Significance

One of the greatest challenges in projecting the sea-level contributions of ice sheets over the next century is the lack of observations of conditions within and underneath the ice sheet that span more than a decade or two. By digitizing archival ice-penetrating radar data recorded in the 1970s on 35-mm optical film, we can compare modern and archival radar-sounding data at their full resolution in order to observe changes in the Antarctic ice sheet over more than 40 y. This makes it possible to investigate and model subsurface processes over both large scales and several decades for the first time.

 

Abstract

Airborne radar sounding can measure conditions within and beneath polar ice sheets. In Antarctica, most digital radar-sounding data have been collected in the last 2 decades, limiting our ability to understand processes that govern longer-term ice-sheet behavior. Here, we demonstrate how analog radar data collected over 40 y ago in Antarctica can be combined with modern records to quantify multidecadal changes. Specifically, we digitize over 400,000 line kilometers of exploratory Antarctic radar data originally recorded on 35-mm optical film between 1971 and 1979. We leverage the increased geometric and radiometric resolution of our digitization process to show how these data can be used to identify and investigate hydrologic, geologic, and topographic features beneath and within the ice sheet. To highlight their scientific potential, we compare the digitized data with contemporary radar measurements to reveal that the remnant eastern ice shelf of Thwaites Glacier in West Antarctica had thinned between 10 and 33% between 1978 and 2009. We also release the collection of scanned radargrams in their entirety in a persistent public archive along with updated geolocation data for a subset of the data that reduces the mean positioning error from 5 to 2.5 km. Together, these data represent a unique and renewed extensive, multidecadal historical baseline, critical for observing and modeling ice-sheet change on societally relevant timescales.

Antarctica – radio echo sounding – glaciology – remote sensing – archival data

Keywords: Antarctica; Climate change; Global warming.

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#Climate drives #spatial #variation in #Zika #epidemics in Latin #America (Proc Roy Soc B., abstract)

[Source: Proceedings of the Royal Society Biological Sciences, full page: (LINK). Abstract, edited.]

Climate drives spatial variation in Zika epidemics in Latin America

Mallory Harris, Jamie M. Caldwell and Erin A. Mordecai

Published: 28 August 2019 / DOI: https://doi.org/10.1098/rspb.2019.1578

 

Abstract

Between 2015 and 2017, Zika virus spread rapidly through populations in the Americas with no prior exposure to the disease. Although climate is a known determinant of many Aedes-transmitted diseases, it is currently unclear whether climate was a major driver of the Zika epidemic and how climate might have differentially impacted outbreak intensity across locations within Latin America. Here, we estimated force of infection for Zika over time and across provinces in Latin America using a time-varying susceptible–infectious–recovered model. Climate factors explained less than 5% of the variation in weekly transmission intensity in a spatio-temporal model of force of infection by province over time, suggesting that week to week transmission within provinces may be too stochastic to predict. By contrast, climate and population factors were highly predictive of spatial variation in the presence and intensity of Zika transmission among provinces, with pseudo-R2 values between 0.33 and 0.60. Temperature, temperature range, rainfall and population size were the most important predictors of where Zika transmission occurred, while rainfall, relative humidity and a nonlinear effect of temperature were the best predictors of Zika intensity and burden. Surprisingly, force of infection was greatest in locations with temperatures near 24°C, much lower than previous estimates from mechanistic models, potentially suggesting that existing vector control programmes and/or prior exposure to other mosquito-borne diseases may have limited transmission in locations most suitable for Aedes aegypti, the main vector of Zika, dengue and chikungunya viruses in Latin America.

Keywords: Zika Virus; Climate change; Latina America.

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On the Emergence of #Candida auris: #ClimateChange, #Azoles, #Swamps, and #Birds (mBio, abstract)

[Source: MBio, full page: (LINK). Abstract, edited.]

On the Emergence of Candida auris: Climate Change, Azoles, Swamps, and Birds

Arturo Casadevall, Dimitrios P. Kontoyiannis, Vincent Robert

James W. Kronstad, Editor

DOI: 10.1128/mBio.01397-19

 

ABSTRACT

The most enigmatic aspect of the rise of Candida auris as a human pathogen is that it emerged simultaneously on three continents, with each clade being genetically distinct. Although new pathogenic fungal species are described regularly, these are mostly species associated with single cases in individuals who are immunosuppressed. In this study, we used phylogenetic analysis to compare the temperature susceptibility of C. auris with those of its close relatives and to use these results to argue that it may be the first example of a new fungal disease emerging from climate change, with the caveat that many other factors may have contributed.

Keywords: Candida Auris; Climate change.

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A 40-y record reveals gradual #Antarctic #sea #ice increases followed by decreases at rates far exceeding the rates seen in the #Arctic (Proc Natl Acad Sci USA, abstract)

[Source: Proceedings of the National Academy of Sciences of the United States of America, full page: (LINK). Abstract, edited.]

A 40-y record reveals gradual Antarctic sea ice increases followed by decreases at rates far exceeding the rates seen in the Arctic

Claire L. Parkinson

PNAS first published July 1, 2019 / DOI: https://doi.org/10.1073/pnas.1906556116

Contributed by Claire L. Parkinson, May 24, 2019 (sent for review April 16, 2019; reviewed by Will Hobbs and Douglas G. Martinson)

 

Significance

A newly completed 40-y record of satellite observations is used to quantify changes in Antarctic sea ice coverage since the late 1970s. Sea ice spreads over vast areas and has major impacts on the rest of the climate system, reflecting solar radiation and restricting ocean/atmosphere exchanges. The satellite record reveals that a gradual, decades-long overall increase in Antarctic sea ice extents reversed in 2014, with subsequent rates of decrease in 2014–2017 far exceeding the more widely publicized decay rates experienced in the Arctic. The rapid decreases reduced the Antarctic sea ice extents to their lowest values in the 40-y record, both on a yearly average basis (record low in 2017) and on a monthly basis (record low in February 2017).

 

Abstract

Following over 3 decades of gradual but uneven increases in sea ice coverage, the yearly average Antarctic sea ice extents reached a record high of 12.8 × 106 km2 in 2014, followed by a decline so precipitous that they reached their lowest value in the 40-y 1979–2018 satellite multichannel passive-microwave record, 10.7 × 106 km2, in 2017. In contrast, it took the Arctic sea ice cover a full 3 decades to register a loss that great in yearly average ice extents. Still, when considering the 40-y record as a whole, the Antarctic sea ice continues to have a positive overall trend in yearly average ice extents, although at 11,300 ± 5,300 km2⋅y−1, this trend is only 50% of the trend for 1979–2014, before the precipitous decline. Four of the 5 sectors into which the Antarctic sea ice cover is divided all also have 40-y positive trends that are well reduced from their 2014–2017 values. The one anomalous sector in this regard, the Bellingshausen/Amundsen Seas, has a 40-y negative trend, with the yearly average ice extents decreasing overall in the first 3 decades, reaching a minimum in 2007, and exhibiting an overall upward trend since 2007 (i.e., reflecting a reversal in the opposite direction from the other 4 sectors and the Antarctic sea ice cover as a whole).

sea ice – climate change – satellite Earth observations – climate trends – Antarctic sea ice

Keywords: Climate change; Global Warming; Antarctica.

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Direct observation of #permafrost #degradation and rapid #soil #carbon loss in #tundra (Nat Geosci., abstract)

[Source: Nature Geoscience, full page: (LINK). Abstract, edited.]

Article | Published: 01 July 2019

Direct observation of permafrost degradation and rapid soil carbon loss in tundra

César Plaza, Elaine Pegoraro, Rosvel Bracho, Gerardo Celis, Kathryn G. Crummer, Jack A. Hutchings, Caitlin E. Hicks Pries, Marguerite Mauritz, Susan M. Natali, Verity G. Salmon, Christina Schädel, Elizabeth E. Webb & Edward A. G. Schuur

Nature Geoscience (2019)

 

Abstract

Evidence suggests that 5–15% of the vast pool of soil carbon stored in northern permafrost ecosystems could be emitted as greenhouse gases by 2100 under the current path of global warming. However, direct measurements of changes in soil carbon remain scarce, largely because ground subsidence that occurs as the permafrost soils begin to thaw confounds the traditional quantification of carbon pools based on fixed depths or soil horizons. This issue is overcome when carbon is quantified in relation to a fixed ash content, which uses the relatively stable mineral component of soil as a metric for pool comparisons through time. We applied this approach to directly measure soil carbon pool changes over five years in experimentally warmed and ambient tundra ecosystems at a site in Alaska where permafrost is degrading due to climate change. We show a loss of soil carbon of 5.4% per year (95% confidence interval: 1.0, 9.5) across the site. Our results point to lateral hydrological export as a potential pathway for these surprisingly large losses. This research highlights the potential to make repeat soil carbon pool measurements at sentinel sites across the permafrost region, as this feedback to climate change may be occurring faster than previously thought.

Keywords: Climate change; Global warming; Permafrost.

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The #effect of #global #change on #mosquito-borne #disease (Lancet Infect Dis., abstract)

[Source: The Lancet Infectious Diseases, full page: (LINK). Abstract, edited.]

The effect of global change on mosquito-borne disease

Lydia H V Franklinos, MSc, Prof Kate E Jones, PhD, David W Redding, PhD, Prof Ibrahim Abubakar, PhD

Published: June 18, 2019 / DOI: https://doi.org/10.1016/S1473-3099(19)30161-6

 

Summary

More than 80% of the global population is at risk of a vector-borne disease, with mosquito-borne diseases being the largest contributor to human vector-borne disease burden. Although many global processes, such as land-use and socioeconomic change, are thought to affect mosquito-borne disease dynamics, research to date has strongly focused on the role of climate change. Here, we show, through a review of contemporary modelling studies, that no consensus on how future changes in climatic conditions will impact mosquito-borne diseases exists, possibly due to interacting effects of other global change processes, which are often excluded from analyses. We conclude that research should not focus solely on the role of climate change but instead consider growing evidence for additional factors that modulate disease risk. Furthermore, future research should adopt new technologies, including developments in remote sensing and system dynamics modelling techniques, to enable a better understanding and mitigation of mosquito-borne diseases in a changing world.

Keywords: Arbovirus; Mosquitoes; Emerging Diseases; Climate Change.

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