Spatial covariance of water isotope records in a global network of ice cores spanning twentieth-century climate change

For several decades, the comparison of climate data with results from water isotope-enabled Atmosphere General Circulation Models (AGCMs) significantly helped to a better understanding of the processes ruling the water cycle, which is one of the main drivers of the climate variability. For the modern period, the use of AGCMs nudged with weather forecasts reanalyses is a powerful way to obtain model outputs under the same weather conditions than at the sampling time of the observations.Here we present new isotopic simulations results from ECHAM6-wiso [1] nudged with the last reanalyses dataset from the European Centre for Medium-Range Weather Forecasts (ECMWF), ERA5 [2], at different spatial resolutions over the period 1979-2018. Model results are evaluated against isotopic data compilations, including GNIP (Global Network of Isotopes in Precipitation [3]), speleothems [4], ice cores datasets and water vapor measurements. To quantify the impact of these reanalyses on our simulations, we also performed nudged simulations with the previous model version ECHAM5-wiso [5] by using ERA5 data and its predecessor ERA-Interim [6].These new simulation products could be a useful contribution to the isotopic data community for the interpretation of their water isotope records and for the exploration of the mechanisms controlling the variability of the surrounding water isotopic composition.&#160;[1] Cauquoin et al., Clim. Past, 15, 1913&#8211;1937, https://doi.org/10.5194/cp-15-1913-2019, 2019.[2] Copernicus Climate Change Service (C3S), 2017.[3] IAEA, the GNIP Database, available at: https://nucleus.iaea.org/wiser.[4] Comas-Bru et al., Clim. Past, 15, 1557&#8211;1579, https://doi.org/10.5194/cp-15-1557-2019, 2019.[5] Werner et al., Geosci. Model Dev., 9, 647&#8211;670, https://doi.org/10.5194/gmd-9-647-2016, 2016.[6] Dee et al., Q. J. R. Meteorol. Soc., 137, 553&#8211;597, https://doi.org/10.1002/qj.828, 2011.

Grassroots and Global Governance: Can Global–Local Linkages Foster Food System Resilience for Small Northern Canadian Communities?

Sustainability ◽

10.3390/su13042415 ◽

2021 ◽

Vol 13 (4) ◽

pp. 2415

Author(s):

Carla Johnston ◽

Andrew Spring

Keyword(s):

Climate Change ◽

Global Governance ◽

Land Tenure ◽

Food Systems ◽

Food System ◽

Global Climate ◽

Local Level ◽

Indigenous Communities ◽

Global Network ◽

Global Networks

Communities in Canada’s Northwest Territories (NWT) are at the forefront of the global climate emergency. Yet, they are not passive victims; local-level programs are being implemented across the region to maintain livelihoods and promote adaptation. At the same time, there is a recent call within global governance literature to pay attention to how global policy is implemented and affecting people on the ground. Thinking about these two processes, we ask the question: (how) can global governance assist northern Indigenous communities in Canada in reaching their goals of adapting their food systems to climate change? To answer this question, we argue for a “community needs” approach when engaging in global governance literature and practice, which puts community priorities and decision-making first. As part of a collaborative research partnership, we highlight the experiences of Ka’a’gee Tu First Nation, located in Kakisa, NWT, Canada. We include their successes of engaging in global network building and the systemic roadblock of lack of formal land tenure. Moreover, we analyze potential opportunities for this community to engage with global governance instruments and continue connecting to global networks that further their goals related to climate change adaptation and food sovereignty.

Glacier ice archives nearly 15,000-year-old microbes and phages

Microbiome ◽

10.1186/s40168-021-01106-w ◽

2021 ◽

Vol 9 (1) ◽

Author(s):

Zhi-Ping Zhong ◽

Funing Tian ◽

Simon Roux ◽

M. Consuelo Gazitúa ◽

Natalie E. Solonenko ◽

...

Keyword(s):

Climate Change ◽

Ice Core ◽

Ice Cores ◽

Single Species ◽

Amplicon Sequencing ◽

Future Climate Change ◽

Climate Conditions ◽

Glacier Ice ◽

Sampling Procedures ◽

Functional Genome

Abstract Background Glacier ice archives information, including microbiology, that helps reveal paleoclimate histories and predict future climate change. Though glacier-ice microbes are studied using culture or amplicon approaches, more challenging metagenomic approaches, which provide access to functional, genome-resolved information and viruses, are under-utilized, partly due to low biomass and potential contamination. Results We expand existing clean sampling procedures using controlled artificial ice-core experiments and adapted previously established low-biomass metagenomic approaches to study glacier-ice viruses. Controlled sampling experiments drastically reduced mock contaminants including bacteria, viruses, and free DNA to background levels. Amplicon sequencing from eight depths of two Tibetan Plateau ice cores revealed common glacier-ice lineages including Janthinobacterium, Polaromonas, Herminiimonas, Flavobacterium, Sphingomonas, and Methylobacterium as the dominant genera, while microbial communities were significantly different between two ice cores, associating with different climate conditions during deposition. Separately, ~355- and ~14,400-year-old ice were subject to viral enrichment and low-input quantitative sequencing, yielding genomic sequences for 33 vOTUs. These were virtually all unique to this study, representing 28 novel genera and not a single species shared with 225 environmentally diverse viromes. Further, 42.4% of the vOTUs were identifiable temperate, which is significantly higher than that in gut, soil, and marine viromes, and indicates that temperate phages are possibly favored in glacier-ice environments before being frozen. In silico host predictions linked 18 vOTUs to co-occurring abundant bacteria (Methylobacterium, Sphingomonas, and Janthinobacterium), indicating that these phages infected ice-abundant bacterial groups before being archived. Functional genome annotation revealed four virus-encoded auxiliary metabolic genes, particularly two motility genes suggest viruses potentially facilitate nutrient acquisition for their hosts. Finally, given their possible importance to methane cycling in ice, we focused on Methylobacterium viruses by contextualizing our ice-observed viruses against 123 viromes and prophages extracted from 131 Methylobacterium genomes, revealing that the archived viruses might originate from soil or plants. Conclusions Together, these efforts further microbial and viral sampling procedures for glacier ice and provide a first window into viral communities and functions in ancient glacier environments. Such methods and datasets can potentially enable researchers to contextualize new discoveries and begin to incorporate glacier-ice microbes and their viruses relative to past and present climate change in geographically diverse regions globally.

North Atlantic jet stream projections in the context of the past 1,250 years

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.2104105118 ◽

2021 ◽

Vol 118 (38) ◽

pp. e2104105118

Author(s):

Matthew B. Osman ◽

Sloan Coats ◽

Sarah B. Das ◽

Joseph R. McConnell ◽

Nathan Chellman

Keyword(s):

21St Century ◽

North Atlantic ◽

Climate Model ◽

Ice Cores ◽

Natural Variability ◽

Jet Stream ◽

Early 21St Century ◽

The North ◽

North Atlantic Jet ◽

Water Isotope

Reconstruction of the North Atlantic jet stream (NAJ) presents a critical, albeit largely unconstrained, paleoclimatic target. Models suggest northward migration and changing variance of the NAJ under 21st-century warming scenarios, but assessing the significance of such projections is hindered by a lack of long-term observations. Here, we incorporate insights from an ensemble of last-millennium water isotope–enabled climate model simulations and a wide array of mean annual water isotope (δ18O) and annually accumulated snowfall records from Greenland ice cores to reconstruct North Atlantic zonal-mean zonal winds back to the 8th century CE. Using this reconstruction we provide preobservational constraints on both annual mean NAJ position and intensity to show that late 20th- and early 21st-century NAJ variations were likely not unique relative to natural variability. Rather, insights from our 1,250 year reconstruction highlight the overwhelming role of natural variability in thus far masking the response of midlatitude atmospheric dynamics to anthropogenic forcing, consistent with recent large-ensemble transient modeling experiments. This masking is not projected to persist under high greenhouse gas emissions scenarios, however, with model projected annual mean NAJ position emerging as distinct from the range of reconstructed natural variability by as early as 2060 CE.

Impact of precipitation intermittency on NAO-temperature signals in proxy records

Climate of the Past ◽

10.5194/cp-9-871-2013 ◽

2013 ◽

Vol 9 (2) ◽

pp. 871-886 ◽

Cited By ~ 23

Author(s):

M. Casado ◽

P. Ortega ◽

V. Masson-Delmotte ◽

C. Risi ◽

D. Swingedouw ◽

...

Keyword(s):

General Circulation ◽

Ice Core ◽

Circulation Model ◽

Ice Cores ◽

Stable Isotope Ratio ◽

Global Network ◽

Temporal Correlations ◽

The North ◽

The North Atlantic Oscillation ◽

The Impact

Abstract. In mid and high latitudes, the stable isotope ratio in precipitation is driven by changes in temperature, which control atmospheric distillation. This relationship forms the basis for many continental paleoclimatic reconstructions using direct (e.g. ice cores) or indirect (e.g. tree ring cellulose, speleothem calcite) archives of past precipitation. However, the archiving process is inherently biased by intermittency of precipitation. Here, we use two sets of atmospheric reanalyses (NCEP (National Centers for Environmental Prediction) and ERA-interim) to quantify this precipitation intermittency bias, by comparing seasonal (winter and summer) temperatures estimated with and without precipitation weighting. We show that this bias reaches up to 10 °C and has large interannual variability. We then assess the impact of precipitation intermittency on the strength and stability of temporal correlations between seasonal temperatures and the North Atlantic Oscillation (NAO). Precipitation weighting reduces the correlation between winter NAO and temperature in some areas (e.g. Québec, South-East USA, East Greenland, East Siberia, Mediterranean sector) but does not alter the main patterns of correlation. The correlations between NAO, δ18O in precipitation, temperature and precipitation weighted temperature are investigated using outputs of an atmospheric general circulation model enabled with stable isotopes and nudged using reanalyses (LMDZiso (Laboratoire de Météorologie Dynamique Zoom)). In winter, LMDZiso shows similar correlation values between the NAO and both the precipitation weighted temperature and δ18O in precipitation, thus suggesting limited impacts of moisture origin. Correlations of comparable magnitude are obtained for the available observational evidence (GNIP (Global Network of Isotopes in Precipitation) and Greenland ice core data). Our findings support the use of archives of past δ18O for NAO reconstructions.

Past temperature reconstructions from deep ice cores: relevance for future climate change

Climate of the Past ◽

10.5194/cp-2-145-2006 ◽

2006 ◽

Vol 2 (2) ◽

pp. 145-165 ◽

Cited By ~ 77

Author(s):

V. Masson-Delmotte ◽

G. Dreyfus ◽

P. Braconnot ◽

S. Johnsen ◽

J. Jouzel ◽

...

Keyword(s):

Climate Change ◽

Temperature Change ◽

Climate Models ◽

Ice Core ◽

Ice Cores ◽

Future Climate ◽

Future Climate Change ◽

Interglacial Period ◽

Temperature Reconstructions

Abstract. Ice cores provide unique archives of past climate and environmental changes based only on physical processes. Quantitative temperature reconstructions are essential for the comparison between ice core records and climate models. We give an overview of the methods that have been developed to reconstruct past local temperatures from deep ice cores and highlight several points that are relevant for future climate change. We first analyse the long term fluctuations of temperature as depicted in the long Antarctic record from EPICA Dome C. The long term imprint of obliquity changes in the EPICA Dome C record is highlighted and compared to simulations conducted with the ECBILT-CLIO intermediate complexity climate model. We discuss the comparison between the current interglacial period and the long interglacial corresponding to marine isotopic stage 11, ~400 kyr BP. Previous studies had focused on the role of precession and the thresholds required to induce glacial inceptions. We suggest that, due to the low eccentricity configuration of MIS 11 and the Holocene, the effect of precession on the incoming solar radiation is damped and that changes in obliquity must be taken into account. The EPICA Dome C alignment of terminations I and VI published in 2004 corresponds to a phasing of the obliquity signals. A conjunction of low obliquity and minimum northern hemisphere summer insolation is not found in the next tens of thousand years, supporting the idea of an unusually long interglacial ahead. As a second point relevant for future climate change, we discuss the magnitude and rate of change of past temperatures reconstructed from Greenland (NorthGRIP) and Antarctic (Dome C) ice cores. Past episodes of temperatures above the present-day values by up to 5°C are recorded at both locations during the penultimate interglacial period. The rate of polar warming simulated by coupled climate models forced by a CO2 increase of 1% per year is compared to ice-core-based temperature reconstructions. In Antarctica, the CO2-induced warming lies clearly beyond the natural rhythm of temperature fluctuations. In Greenland, the CO2-induced warming is as fast or faster than the most rapid temperature shifts of the last ice age. The magnitude of polar temperature change in response to a quadrupling of atmospheric CO2 is comparable to the magnitude of the polar temperature change from the Last Glacial Maximum to present-day. When forced by prescribed changes in ice sheet reconstructions and CO2 changes, climate models systematically underestimate the glacial-interglacial polar temperature change.

Multimodel Multisignal Climate Change Detection at Regional Scale

Journal of Climate ◽

10.1175/jcli3851.1 ◽

2006 ◽

Vol 19 (17) ◽

pp. 4294-4307 ◽

Cited By ~ 50

Author(s):

Xuebin Zhang ◽

Francis W. Zwiers ◽

P. A. Stott

Keyword(s):

Climate Change ◽

Twentieth Century ◽

Greenhouse Gases ◽

Regional Scale ◽

Internal Variability ◽

Anthropogenic Forcing ◽

Internal Climate Variability ◽

Aerosol Forcing ◽

Spatial Domains ◽

Northern Hemispheric

Abstract Using an optimal detection technique and climate change simulations produced with two versions of two GCMs, we have assessed the causes of twentieth-century temperature changes from global to regional scales. Our analysis is conducted in nine spatial domains: 1) the globe; 2) the Northern Hemisphere; four large regions in the Northern Hemispheric midlatitudes covering 30°–70°N including 3) Eurasia, 4) North America, 5) Northern Hemispheric land only, 6) the entire 30°–70°N belt; and three smaller regions over 7) southern Canada, 8) southern Europe, and 9) China. We find that the effect of anthropogenic forcing on climate is clearly detectable at global through regional scales. The effect of combined greenhouse gases and sulfate aerosol forcing is detectable in all nine domains in annual and seasonal mean temperatures observed during the second half of the twentieth century. The effect of greenhouse gases can also be separated from that of sulfate aerosols over this period at continental and regional scales. Uncertainty in these results is larger in the smaller spatial domains. Detection is improved when an ensemble of models is used to estimate the response to anthropogenic forcing and the underlying internal variability of the climate system. Our detection results hold after removal of North Atlantic Oscillation (NAO)-related variability in temperature observations—variability that may or may not be associated with anthropogenic forcing. They also continue to hold when our estimates of natural internal climate variability are doubled.

Evidence of Abrupt Climate Change and the Development of an Historic Mercury Deposition Record Using Chronological Refinement of Ice Cores at Upper Fremont Glacier

Earth Paleoenvironments: Records Preserved in Mid- and Low-Latitude Glaciers - Developments in Paleoenvironmental Research ◽

10.1007/1-4020-2146-1_10 ◽

2006 ◽

pp. 181-216

Author(s):

Paul F. Schuster ◽

David L. Naftz ◽

L. DeWayne Cecil ◽

Jaromy R. Green

Keyword(s):

Climate Change ◽

Ice Cores ◽

Abrupt Climate Change ◽

Mercury Deposition

Earth Ethics and American Catholic Environmentalism

Catholic Social Activism ◽

10.18574/nyu/9781479885480.003.0007 ◽

2019 ◽

pp. 146-162

Author(s):

Sharon Erickson Nepstad

Keyword(s):

Climate Change ◽

Twentieth Century ◽

Catholic Church ◽

First Century ◽

Human Needs ◽

Early Twenty ◽

The Us ◽

American Catholic ◽

Activist Groups ◽

The Catholic Church

This chapter notes that American Catholics were initially quite reluctant to embrace environmentalism. It asks, after decades of political engagement with labor, poverty, peace, women’s rights, and immigration, why did US Catholics largely overlook the growing environmental problems in the twentieth century? And what caused this to change in the early twenty-first century? The chapter summarizes early Catholic efforts to promote environmentalism and describes the initial responses of the Catholic Church and its members, who often prioritized human needs over environmental matters. It also describes how the Catholic Church and Catholic laypeople started placing greater emphasis on the environment toward the end of the twentieth century. The chapter then surveys the main themes of various Catholic teachings and publications—from the US Catholic Bishops Conference’s Renewing the Earth (1991) to Pope Francis’s encyclical Laudato Si (2015)—that have given impetus to more Catholic environmental action. The chapter concludes with a description of the work of two activist groups: the National Religious Partnership for the Environment, an ecumenical organization, and Catholic Climate Change.

The Impacts of Climate Change on Societies: What Can We Learn from the Past?

10.5194/egusphere-egu21-99 ◽

2021 ◽

Author(s):

Dagomar Degroot

Keyword(s):

Climate Change ◽

Case Studies ◽

Public Discourse ◽

Climate Change Policy ◽

Ice Cores ◽

Keynote Presentation ◽

The Past ◽

Change Policy ◽

History Of ◽

Paleoclimatic Proxy

This keynote presentation introduces the sources, methods, and major findings of the History of Climate and Society (HCS), a recently-coined field that uncovers the past influences of climate change on human history. It begins by offering a brief history of the field, from the eighteenth century through the present. It then describes how HCS scholars &#8220;reconstruct&#8221; past climate changes by combining what they call the &#8220;archives of nature&#8221; &#8211; paleoclimatic proxy sources such as tree rings, ice cores, or marine sediments &#8211; with the texts, stories, and ruins that constitute the &#8220;archives of society.&#8221; Next, it explains how HCS scholars in different disciplines have used distinct statistical and qualitative methods, and distinct causal frameworks, to identify the influence of climate change in the archives of society. It explores how HCS scholars conceptualize the vulnerability and resilience of past societies by introducing some telling case studies, and explaining how those case studies have grown more complex as HCS matured as a field. It then emphasizes the enduring challenges faced by HCS scholars and how, in recent months, they have been identified and are beginning to be addressed. Finally, it describes how HCS has informed climate change policy and public discourse, before offering some key lessons that policymakers can learn from the field.