Water isotope ratios reflect convection intensity rather than rain type proportions in the pantropics.

Against the traditional view, a recently published theory argued that isotope ratios are higher in convective precipitation but lower in stratiform precipitation and proposed that isotope ratios reflect rain type proportions. This theory has been widely cited despite some early reservations. Whether the theory represents a faithful reflection of signals of water isotope ratios remains unclear.

Tropical mountain ice core δO: A Goldilocks indicator for global temperature change.

Very high tropical alpine ice cores provide a distinct paleoclimate record for climate changes in the middle and upper troposphere. However, the climatic interpretation of a key proxy, the stable water oxygen isotopic ratio in ice cores (δO), remains an outstanding problem. Here, combining proxy records with climate models, modern satellite measurements, and radiative-convective equilibrium theory, we show that the tropical δO is an indicator of the temperature of the middle and upper troposphere, with a glacial cooling of -7.

Use of δO in dating a Tibetan ice core record of Holocene/Late Glacial climate.

Ice cores from the northwestern Tibetan Plateau (NWTP) contain long records of regional climate variability, but refrozen meltwater and dust in these cores has hampered development of robust timescales. Here, we introduce an approach to dating the ice via the isotopic composition of atmospheric O in air bubbles (δO), along with annual layer counting and radiocarbon dating. We provide a robust chronology for water isotope records (δO and d-excess) from three ice cores from the Guliya ice cap in the NWTP.

Westerly drives long-distance transport of radionuclides from nuclear events to glaciers in the Third Pole.

Major nuclear bomb tests and nuclear power plant incidents release large amounts of radionuclides. This study investigates beta (β) activities of radionuclides from four ice cores in the Third Pole (TP) to understand the transport routes and related atmospheric processes affecting the radionuclides deposition in glaciers of the region. All the ice cores show three major β activity peaks in the ice layers corresponding to 1963, 1986, and 2011.

Inverse altitude effect disputes the theoretical foundation of stable isotope paleoaltimetry.

Stable isotope paleoaltimetry that reconstructs paleoelevation requires stable isotope (δD or δO) values to follow the altitude effect. Some studies found that the δD or δO values of surface isotopic carriers in some regions increase with increasing altitude, which is defined as an "inverse altitude effect" (IAE). The IAE directly contradicts the basic theory of stable isotope paleoaltimetry.

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

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.

Early atmospheric contamination on the top of the Himalayas since the onset of the European Industrial Revolution.

Because few ice core records from the Himalayas exist, understanding of the onset and timing of the human impact on the atmosphere of the "roof of the world" remains poorly constrained. We report a continuous 500-y trace metal ice core record from the Dasuopu glacier (7,200 m, central Himalayas), the highest drilling site on Earth. We show that an early contamination from toxic trace metals, particularly Cd, Cr, Mo, Ni, Sb, and Zn, emerged at high elevation in the Himalayas at the onset of the European Industrial Revolution (∼1780 AD).

Disappearance of the last tropical glaciers in the Western Pacific Warm Pool (Papua, Indonesia) appears imminent.

The glaciers near Puncak Jaya in Papua, Indonesia, the highest peak between the Himalayas and the Andes, are the last remaining tropical glaciers in the West Pacific Warm Pool (WPWP). Here, we report the recent, rapid retreat of the glaciers near Puncak Jaya by quantifying the loss of ice coverage and reduction of ice thickness over the last 8 y. Photographs and measurements of a 30-m accumulation stake anchored to bedrock on the summit of one of these glaciers document a rapid pace in the loss of ice cover and a ∼5.

Central Tibetan Plateau atmospheric trace metals contamination: A 500-year record from the Puruogangri ice core.

A ~500-year section of ice core (1497-1992) from the Puruogangri ice cap has been analyzed at high resolution for 28 trace elements (TEs: Ag, Al, As, Ba, Bi, Cd, Co, Cr, Cs, Cu, Fe, Ga, Li, Mg, Mn, Na, Nb, Ni, Pb, Rb, Sb, Sn, Sr, Ti, Tl, U, V and Zn) to assess different atmospheric contributions to the ice and provide a temporal perspective on the diverse atmospheric influences over the central Tibetan Plateau (TP). At least two volcanic depositions have significantly impacted the central TP over the past 500years, possibly originating from the Billy Mitchell (1580, Papua New Guinea) and the Parker Peak (1641, Philippines) eruptions. A decreasing aeolian dust input to the ice cap allowed the detection of an atmospheric pollution signal.

Widespread pollution of the South American atmosphere predates the industrial revolution by 240 y.

In the Southern Hemisphere, evidence for preindustrial atmospheric pollution is restricted to a few geological archives of low temporal resolution that record trace element deposition originating from past mining and metallurgical operations in South America. Therefore, the timing and the spatial impact of these activities on the past atmosphere remain poorly constrained. Here we present an annually resolved ice core record (A.

Reconstructed changes in Arctic sea ice over the past 1,450 years.

Arctic sea ice extent is now more than two million square kilometres less than it was in the late twentieth century, with important consequences for the climate, the ocean and traditional lifestyles in the Arctic. Although observations show a more or less continuous decline for the past four or five decades, there are few long-term records with which to assess natural sea ice variability. Until now, the question of whether or not current trends are potentially anomalous has therefore remained unanswerable.

Understanding global climate change: paleoclimate perspective from the world's highest mountains.

Glaciers are among the world's best recorders of, and first responders to, natural and anthropogenic climate change and provide a time perspective for current climatic and environmental variations. Over the last 50 years such records have been recovered from the polar regions as well as low-latitude, high-elevation ice fields. Analyses of these ice cores and of the glaciers from which they have been drilled have yielded three lines of evidence for past and present abrupt climate change: (1) the temperature and precipitation histories recorded in the glaciers as revealed by the climate records extracted from the ice cores; (2) the accelerating loss of the glaciers themselves; and (3) the uncovering of ancient fauna and flora from the margins of the glaciers as a result of their recent melting, thus illustrating the significance of the current ice loss.

Climate change: the evidence and our options.

Glaciers serve as early indicators of climate change. Over the last 35 years, our research team has recovered ice-core records of climatic and environmental variations from the polar regions and from low-latitude high-elevation ice fields from 16 countries. The ongoing widespread melting of high-elevation glaciers and ice caps, particularly in low to middle latitudes, provides some of the strongest evidence to date that a large-scale, pervasive, and, in some cases, rapid change in Earth's climate system is underway.

Abrupt tropical climate change: past and present.

Three lines of evidence for abrupt tropical climate change, both past and present, are presented. First, annually and decadally averaged delta(18)O and net mass-balance histories for the last 400 and 2,000 yr, respectively, demonstrate that the current warming at high elevations in the mid- to low latitudes is unprecedented for at least the last 2 millennia. Second, the continuing retreat of most mid- to low-latitude glaciers, many having persisted for thousands of years, signals a recent and abrupt change in the Earth's climate system.

Atmospheric heavy metals in tropical South America during the past 22,000 years recorded in a high altitude ice core from Sajama, Bolivia.

V, Co, Cu, Zn, As, Rb, Sr, Ag, Cd, Ba, Pb, Bi and U have been analysed by inductively coupled plasma sector field mass spectrometry in various sections of a dated snow/ice core drilled at an altitude of 6542 m on the Sajama ice cap in Bolivia. The analysed sections were dated from the Last Glacial Stage ( approximately 22,000 years ago), the Mid-Holocene and the last centuries. The observed variations of crustal enrichment factors (EFc) for the various metals show contrasting situations.

Bacterial recovery from ancient glacial ice.

Ice that forms the bottom 18 m of a 308 m ice core drilled from the Guliya ice cap on the Qinghan-Tibetan plateau in Western China is over 750000 years old and is the oldest glacial ice known to date. Fourteen bacterial isolates have been recovered from samples of this ice from approximately 296 m below the surface (mbs). Based on 16S rDNA sequences, these are members of the alpha- and beta-proteobacterial, actinobacterial and low-G + C Gram-positive bacterial lineages.

Kilimanjaro ice core records: evidence of holocene climate change in tropical Africa.

Six ice cores from Kilimanjaro provide an approximately 11.7-thousand-year record of Holocene climate and environmental variability for eastern equatorial Africa, including three periods of abrupt climate change: approximately 8.3, approximately 5.