Search

Your search keyword '"Schmidt, D.N."' showing total 34 results
Start Over Author "Schmidt, D.N."
34 results on '"Schmidt, D.N."'

1. Plio-pleistocene climate sensitivity evaluated using high-resolution C[O.sub.2] records

Author

Martinez-Boti, M.A., Foster, G.L., Chalk, T.B., Rohling, E.J., Sexton, P.F., Lunt, D.J., Pancost, R.D., Badger, M.P.S., and Schmidt, D.N.

Subjects
Paleoclimatology -- Research, Atmospheric carbon dioxide -- Environmental aspects -- Research, Climate sensitivity -- Research, Environmental issues, Science and technology, Zoology and wildlife conservation
Abstract

Theory and climate modelling suggest that the sensitivity of Earth's climate to changes in radiative forcing could depend on the background climate. However, palaeoclimate data have thus far been insufficient to provide a conclusive test of this prediction. Here we present atmospheric carbon dioxide (C[O.sub.2]) reconstructions based on multi-site boron- isotope records from the late Pliocene epoch (3.3 to 2.3 million years ago). We find that Earth's climate sensitivity to C[O.sub.2]-based radiative forcing (Earth system sensitivity) was half as strong during the warm Pliocene as during the cold late Pleistocene epoch(0.8 to 0.01 million years ago). We attribute this difference to the radiative impacts of continental ice-volume changes (the ice-albedo feedback) during the late Pleistocene, because equilibrium climate sensitivity is identical for the two intervals when we account for such impacts using sea-level reconstructions. We conclude that, on a global scale, no unexpected climate feedbacks operated during the warm Pliocene, and that predictions of equilibrium climate sensitivity (excluding long-term ice-albedo feedbacks) for our Pliocene-like future (with C[O.sub.2] levels up to maximum Pliocene levels of 450 parts per million) are well described by the currently accepted range of an increase of 1.5K to 4.5K per doubling of C[O.sub.2]., Since the start of the industrial revolution, the concentration of atmospheric C[O.sub.2] (and other greenhouse gases) has increased dramatically (from ~280 to ~400 parts per million) (1). It has been [...]

Published
2015
Full Text
View/download PDF

2. Europe (Chapter 13)

Author

Pörtner, H.-O., Roberts, D.C., Tignor, M., Poloczanska, E.S., Mintenbeck, K, Alegría, A., Craig, M., Langsdorf, S., Löschke, S., Möller, V., Okem, A., Rama, B., Bednar-Friedl, B., Biesbroek, R., Schmidt, D.N., Alexander, P., Børsheim, K.Y., Carnicer, J, Georgopoulou, E., Haasnoot, M., Le Cozzanet, G., Lionello, P., Lipka, O., Möllmann, C., Muccione, V., Mustonen, T., Piepenburg, D., Whitmarsh, L., Pörtner, H.-O., Roberts, D.C., Tignor, M., Poloczanska, E.S., Mintenbeck, K, Alegría, A., Craig, M., Langsdorf, S., Löschke, S., Möller, V., Okem, A., Rama, B., Bednar-Friedl, B., Biesbroek, R., Schmidt, D.N., Alexander, P., Børsheim, K.Y., Carnicer, J, Georgopoulou, E., Haasnoot, M., Le Cozzanet, G., Lionello, P., Lipka, O., Möllmann, C., Muccione, V., Mustonen, T., Piepenburg, D., and Whitmarsh, L.

Abstract

Our current 1.1°C warmer world is already affecting natural and human systems in Europe (very high confidence1). Since AR5, there has been a substantial increase in detected or attributed impacts of climate change in Europe, including extreme events (high confidence). Impacts of compound hazards of warming and precipitation have become more frequent (medium confidence). Climate change has resulted in losses of, and damages to, people, ecosystems, food systems, infrastructure, energy and water availability, public health and the economy (very high confidence).

Published
2022

3. Technical Summary

Author

Pörtner, Hans-Otto, Roberts, D.C., Adams, H., Adelekan, I., Adler, C., Adrian, R., Aldunce, Paulina, Ali, Elham, Ara Begum, R., Bednar-Friedl, B., Kerr, Rachel Bezner, Biesbroek, G.R., Birkmann, J., Bowen, K., Caretta, M.A., Carnicer, Jofre, Castellanos, Edwin, Cheong, T.S., Chow, W., Cissé, Guéladio, Clayton, S., Constable, A., Cooley, S.R., Costello, M.J., Craig, M., Cramer, W., Dawson, R., Dodman, D., Efitre, J., Garschagen, M., Gilmore, E.A., Glavovic, B.C., Gutzler, D., Haasnoot, M., Harper, S., Hasegawa, T., Hayward, B., Hicke, J.A., Hirabayashi, Y., Huang, C., Kalaba, K., Kiessling, W., Kitoh, A., Lasco, R., Lawrence, J., Lemos, M.F., Lempert, R., Lennard, C., Ley, D., Lissner, T., Liu, Q., Liwenga, E., Lluch-Cota, Salvador, Löschke, S., Lucatello, S., Luo, Y., Mackey, B., Mintenbeck, Katja, Mirzabaev, A., Möller, V., Moncassim Vale, Mariana, Morecroft, M.D., Mortsch, L., Mukherji, A., Mustonen, Tero, Mycoo, Michelle, Nalau, J., New, M., Okem, A., Ometto, J.P., O'Neill, B., Pandey, R., Parmesan, Camille, Pelling, Mark, Pinho, P.F., Pinnegar, J., Poloczanska, E.S., Prakash, A., Preston, B., Racault, Marie-Fanny, Reckien, Diana, Revi, A., Rose, S.K., Schipper, E.L.F., Schmidt, D.N., Schoeman, D., Shaw, R., Simpson, N.P., Singh, C., Solecki, W., Stringer, L., Totin, E., Trisos, C.H., Trisurat, Y., van Aalst, M., Viner, D., Wairiu, Morgan, Warren, R., Wester, P., Wrathall, David, Zaiton Ibrahim, Zelina, Pörtner, Hans-Otto, Roberts, D.C., Adams, H., Adelekan, I., Adler, C., Adrian, R., Aldunce, Paulina, Ali, Elham, Ara Begum, R., Bednar-Friedl, B., Kerr, Rachel Bezner, Biesbroek, G.R., Birkmann, J., Bowen, K., Caretta, M.A., Carnicer, Jofre, Castellanos, Edwin, Cheong, T.S., Chow, W., Cissé, Guéladio, Clayton, S., Constable, A., Cooley, S.R., Costello, M.J., Craig, M., Cramer, W., Dawson, R., Dodman, D., Efitre, J., Garschagen, M., Gilmore, E.A., Glavovic, B.C., Gutzler, D., Haasnoot, M., Harper, S., Hasegawa, T., Hayward, B., Hicke, J.A., Hirabayashi, Y., Huang, C., Kalaba, K., Kiessling, W., Kitoh, A., Lasco, R., Lawrence, J., Lemos, M.F., Lempert, R., Lennard, C., Ley, D., Lissner, T., Liu, Q., Liwenga, E., Lluch-Cota, Salvador, Löschke, S., Lucatello, S., Luo, Y., Mackey, B., Mintenbeck, Katja, Mirzabaev, A., Möller, V., Moncassim Vale, Mariana, Morecroft, M.D., Mortsch, L., Mukherji, A., Mustonen, Tero, Mycoo, Michelle, Nalau, J., New, M., Okem, A., Ometto, J.P., O'Neill, B., Pandey, R., Parmesan, Camille, Pelling, Mark, Pinho, P.F., Pinnegar, J., Poloczanska, E.S., Prakash, A., Preston, B., Racault, Marie-Fanny, Reckien, Diana, Revi, A., Rose, S.K., Schipper, E.L.F., Schmidt, D.N., Schoeman, D., Shaw, R., Simpson, N.P., Singh, C., Solecki, W., Stringer, L., Totin, E., Trisos, C.H., Trisurat, Y., van Aalst, M., Viner, D., Wairiu, Morgan, Warren, R., Wester, P., Wrathall, David, and Zaiton Ibrahim, Zelina

Published
2022

4. Europe : from Chapters and Cross-Chapter Papers

Author

Bednar-Friedl, Birgit, Biesbroek, G.R., Schmidt, D.N., Alexander, P., Børsheim, K.Y., Carnicer, Jofre, Georgopoulou, E., Haasnoot, M., Le Cozannet, G., Lionello, P., Lipka, O., Möllmann, Christian, Muccione, Veruska, Mustonen, Tero, Piepenburg, Dieter, Whitmarsh, L., Rama, B., Bednar-Friedl, Birgit, Biesbroek, G.R., Schmidt, D.N., Alexander, P., Børsheim, K.Y., Carnicer, Jofre, Georgopoulou, E., Haasnoot, M., Le Cozannet, G., Lionello, P., Lipka, O., Möllmann, Christian, Muccione, Veruska, Mustonen, Tero, Piepenburg, Dieter, Whitmarsh, L., and Rama, B.

Published
2022

6. Tracers of uplift and subsidence in the Cape Verde archipelago

Author

Ramalho, R., Helffrich, G., Schmidt, D.N., and Vance, D.

Subjects
Cape Verde -- Environmental aspects, Volcanism -- Research, Geology, Stratigraphic -- Research, Geomorphology -- Research, Earth sciences
Abstract

Ocean islands are subject to vertical movements through their lifetime and these movements' origins are poorly understood. Tracking island freeboard provides insight into the mechanisms that cause these movements. The Cape Verde archipelago is the result of hotspot volcanism ranging from 26 Ma to the present, and constitutes a structural pile that has preserved a record of the palaeo-positions of mean sea level. These palaeo-markers, both sedimentary and volcanic, are datable and can be used to track the island's history of vertical movements when used in conjunction with a eustatic curve. We have studied the volcanostratigraphy of Cape Verde and mapped the palaeo-marker positions and features, and we provide the sea-level height information that can be estimated through them. Evidence exists for differential uplift histories throughout the archipelago, with substantial uplift in some of the islands synchronous with volcanism. Other islands, in contrast, exhibit evidence for stability or complex uplift subsidence histories. Supplementary material: Detailed island geology information is available at http://www.geolsoc.org.uk/SUP18390. doi: 10.1144/0016-76492009-056.

Published
2010

7. Assessing bulk carbonates as archives for seawater Li isotope ratios

Author

Pogge von Strandmann, Philip A.E., Schmidt, D.N., Planavsky, N.J., Wei, G., Todd, C.L., and Baumann, K.-H.

Subjects
es
Abstract

Silicate weathering is a primary control on the carbon cycle and therefore long-term climate. Tracing silicate weathering in the geological record has been a challenge for decades, with a number of proxies proposed and their limits determined. Recently lithium isotopes in marine carbonates have emerged as a potential tracer. Bulk carbonates are increasingly being used as a Li isotope archive, though with limited tests thus far of the robustness of this approach in the modern ocean. As the bulk composition of marine pelagic carbonates has changed through time and geographically, assessing the fidelity of bulk carbonate as proxy carrier is fundamental. To address the impact of compositional variability in bulk carbonate on Li isotopes, we examine 27 Bahamian aragonitic bulk carbonates and 16 Atlantic largely calcitic core-top sediment samples. Two core-tops only have trace (

Published
2019

8. Technical summary

Author

Field, C.B., Barros, V.R., Mach, K.J., Mastrandrea, M.D., van Aalst, R.A., Adger, W.N., Arent, D.J., Barnett, J., Betts, R.A., Bilir, T.E., Birkmann, J., Carmin, J., Chadee, D.D., Challinor, A.J., Chatterjee, M., Cramer, W., Davidson, D.J., Estrada, Y.O., Gattuso, J.-P., Hijioka, Y., Hoegh-Guldberg, O., Huang, H.-Q., Insarov, G.E., Jones, R.N., Kovats, R.S., Larsen, J.N., Losada, I.J., Marengo, J.A., McLean, R.F., Mearns, L.O., Mechler, R., Morton, J.F., Niang, I., Oki, T., Olwoch, J.M., Opondo, M., Poloczanska, E.S., Pörtner, H.-O., Romero-Lankao, P., Schmidt, D.N., Shaw, M.R., Solecki, W., Stone, D.A., Stone, J.M.R., Strzepek, K.M., Suarez, A.G., Tschakert, P., Valentini, R., Vicuña, S., Villamizar, A., Vincent, K.E., Warren, R., White, L.L., Wilbanks, T.J., Wong, P.P., and Yohe, G.W.

Subjects
sense organs, skin and connective tissue diseases
Abstract

Human interference with the climate system is occurring. Climate change poses risks for human and natural systems. The assessment of impacts, adaptation, and vulnerability in the Working Group II contribution to the IPCC's Fifth Assessment Report (WGII AR5) evaluates how patterns of risks and potential benefits are shifting due to climate change and how risks can be reduced through mitigation and adaptation. It recognizes that risks of climate change will vary across regions and populations, through space and time, dependent on myriad factors including the extent of mitigation and adaptation.

Published
2014

9. Climate model and proxy data constraints on ocean warming across the Paleocene-Eocene Thermal Maximum

Author

Dunkley Jones, T., Lunt, D.J., Schmidt, D.N., Ridgwell, A., Sluijs, A., Valdes, P.J., Maslin, M., Marine Palynology, and Marine palynology and palaeoceanography

Subjects
PETM, 010504 meteorology & atmospheric sciences, Effects of global warming on oceans, Climate, Earth and Planetary Sciences(all), Geographic variation, 010502 geochemistry & geophysics, Eocene, 01 natural sciences, Proxy (climate), HYDRATE DESTABILIZATION, Taverne, 14. Life underwater, TETRAETHER LIPIDS, CIRCULATION CHANGES, 0105 earth and related environmental sciences, PLANKTONIC-FORAMINIFERA, MEMBRANE-LIPIDS, CORE-TOP CALIBRATION, Sea surface temperature, SEAWATER CHEMISTRY, 13. Climate action, CALCITE-ARAGONITE SEAS, Climatology, Greenhouse gas, SEA-SURFACE TEMPERATURE, Carbon isotope excursion, General Earth and Planetary Sciences, Climate sensitivity, Paleocene, Climate model, SOUTHWEST PACIFIC-OCEAN, Warming, Geology
Abstract

Constraining the greenhouse gas forcing, climatic warming and estimates of climate sensitivity across ancient large transient warming events is a major challenge to the palaeoclimate research community. Here we provide a new compilation and synthesis of the available marine proxy temperature data across the largest of these hyperthermals, the Paleocene-Eocene Thermal Maximum (PETM). This includes the application of consistent temperature calibrations to all data, including the most recent set of calibrations for archaeal lipid-derived palaeothermometry. This compilation provides the basis for an informed discussion of the likely range of PETM warming, the biases present in the existing record and an initial assessment of the geographical pattern of PETM ocean warming. To aid interpretation of the geographic variability of the proxy-derived estimates of PETM warming, we present a comparison of this data with the patterns of warming produced by high pCO(2) simulations of Eocene climates using the Hadley Centre atmosphere-ocean general circulation model (AOGCM) HadCM3L On the basis of this comparison and taking into account the patterns of intermediate-water warming we estimate that the global mean surface temperature anomaly for the PETM is within the range of 4 to 5 degrees C. (C) 2013 Elsevier B.V. All rights reserved.

Published
2013
Full Text
View/download PDF

10. The Geological Record of Ocean Acidification

Author

Hxf6nisch, B, Ridgwell, A, Schmidt, D.N, Thomas, E, Gibbs, S.J, Sluijs, A, Zeebe, R, Kump, L, Martindale, R.C, Greene, S.E, Kiessling, W, Ries, J, Zachos, J.C, Royer, D.L, Barker, S, Marchitto Jr, T.M, Moyer, R, Pelejero, C, Ziveri, P, Foster, G.L, and Williams, B.

Published
2012

11. Paleoceanographic changes in the Eastern Equatorial Pacific over the last 10 Myr

Author

Seki, O., Schmidt, D.N., Schouten, S., Hopmans, E.C., Sinninghe Damsté, J.S., and Pancost, R.D.

Abstract

To examine the Late Neogene evolution of tropical Pacific oceanography, we determined multiple geochemical proxy records for temperature (U-37(K)' and TEX86H indices) and primary productivity (algal biomarkers and diol indices) in sediments recovered at ODP Site 1241 in the East Equatorial Pacific (EEP) spanning a record of the last 10 Myr. The TEX86H temperatures are lower than those recorded by U-37(K)' indices, exhibiting large fluctuations and suggesting strong warming during the Mid Pliocene Warm Period (MPWP; 4.5-3.2 Ma) and significantly colder temperature during the Late Miocene cooling period (7-5 Ma) and after the Middle Pliocene Warm Period (MPWP). Such variations could reflect changes in the EEP thermocline temperatures, but we suggest that they instead reflect changes in the depth of export production of glycerol dialkyl glycerol tetraether lipids in response to changes in the upper ocean structure. A combination of temperature records, inferred to represent different and likely varying depths in the water column, as well as algal biomarker records for export production and ecosystem structure, suggest that both productivity and inference upwelling were reduced in the EEP during warmer periods, such as the MPWP and prior to 7 Ma. In contrast, stronger upwelling conditions and associated increased productivity likely prevailed from 7 to 5 Ma and for the past 3 Myr, both corresponding to globally cool intervals. A further increase in EEP productivity occurred at ca 1.8 Ma, coincident with the development of the E-W Pacific SST gradient. These results confirm previous work that protracted El Nino-like conditions prevailed during warmer intervals of the Pliocene before ultimately descending into the current climate state.

Published
2012

14. IPCC 2014 : Summary for policymakers

Author

Field, C.B., Barros, V.R., Dokken, D.J., Mach, K.J., Mastrandrea, M.D., Bilir, T.E., Chatterjee, M., Ebi, K.L., Estrada, Y.O., Genova, R.C., Girma, B., Kissel, E.S., Levy, A.N., MacCracken, S., Mastrandrea, P.R., White, L.L., Abdrabo, M.A.K., Adger, W.N., Anokhin, Y.A., Anisimov, O.A., Arent, D.J., Barnett, J., Burkett, V.R., Cai, R., Cohen, S.J., Cramer, W., Dasgupta, P., Davidson, D.J., Denton, F., Döll, P., Dow, K., Hijioka, Y., Hoegh-Guldberg, O., Jones, R.G., Jones, R.N., Kitching, R.L., Kovats, R.S., Lankao, P.R., Larsen, J.N., Lin, J.N., Lin, E., Lobell, D.B., Losada, I.J., Magrin, G.O., Marengo, J.A., Markandya, A., McCarl, B.A., McLean, R.F., Mearns, L.O., Midgley, G.F., Mimura, N., Morton, J.F., Niang, I., Noble, I.R., Nurse, L.A., O’Brien, K.L., Oki, T., Olsson, L., Oppenheimer, M., Overpeck, J.T., Pereira, J.J., Poloczanska, E.S., Porter, J.R., Pörtner, H.-O., Prather, M.J., Pulwarty, R.S., Reisinger, A.R., Revi, A., Ruppel, O.C., Satterthwaite, D.E., Schmidt, D.N., Settele, Josef, Smith, K.R., Stone, D.A., Suarez, A.G., Tschakert, P., Valentini, R., Villamizar, A., Warren, R., Wilbanks, T.J., Wong, P.P., Woodward, A., Yohe, G.W., Field, C.B., Barros, V.R., Dokken, D.J., Mach, K.J., Mastrandrea, M.D., Bilir, T.E., Chatterjee, M., Ebi, K.L., Estrada, Y.O., Genova, R.C., Girma, B., Kissel, E.S., Levy, A.N., MacCracken, S., Mastrandrea, P.R., White, L.L., Abdrabo, M.A.K., Adger, W.N., Anokhin, Y.A., Anisimov, O.A., Arent, D.J., Barnett, J., Burkett, V.R., Cai, R., Cohen, S.J., Cramer, W., Dasgupta, P., Davidson, D.J., Denton, F., Döll, P., Dow, K., Hijioka, Y., Hoegh-Guldberg, O., Jones, R.G., Jones, R.N., Kitching, R.L., Kovats, R.S., Lankao, P.R., Larsen, J.N., Lin, J.N., Lin, E., Lobell, D.B., Losada, I.J., Magrin, G.O., Marengo, J.A., Markandya, A., McCarl, B.A., McLean, R.F., Mearns, L.O., Midgley, G.F., Mimura, N., Morton, J.F., Niang, I., Noble, I.R., Nurse, L.A., O’Brien, K.L., Oki, T., Olsson, L., Oppenheimer, M., Overpeck, J.T., Pereira, J.J., Poloczanska, E.S., Porter, J.R., Pörtner, H.-O., Prather, M.J., Pulwarty, R.S., Reisinger, A.R., Revi, A., Ruppel, O.C., Satterthwaite, D.E., Schmidt, D.N., Settele, Josef, Smith, K.R., Stone, D.A., Suarez, A.G., Tschakert, P., Valentini, R., Villamizar, A., Warren, R., Wilbanks, T.J., Wong, P.P., Woodward, A., and Yohe, G.W.

Published
2014

17. Habitat tracking as a response of the planktic foraminifer Globorotalia truncatulinoides to environmental fluctuations during the last 140 kyr

Author

Renaud, Sabrina, Schmidt, D.N., Ecologie et évolution des populations, Département écologie évolutive [LBBE], Laboratoire de Biométrie et Biologie Evolutive - UMR 5558 (LBBE), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Recherche en Informatique et en Automatique (Inria)-VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Recherche en Informatique et en Automatique (Inria)-VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS)-Centre National de la Recherche Scientifique (CNRS)-Laboratoire de Biométrie et Biologie Evolutive - UMR 5558 (LBBE), and Université de Lyon-Université de Lyon-Institut National de Recherche en Informatique et en Automatique (Inria)-VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[SDV.OT]Life Sciences [q-bio]/Other [q-bio.OT]
Published
2003

19. The geological record of ocean acidification

Author

Hönisch, B., Ridgwell, A., Schmidt, D.N., Thomas, E., Gibbs, S.J., Sluijs, A., Zeebe, R., Kump, L., Martindale, R.C., Greene, S.E., Kiessling, W., Ries, J., Zachos, J.C., Royer, D.L., Barker, S., Marchitto Jr., T.M., Moyer, R., Pelejero, C., Ziveri, P., Foster, G.L., Williams, B., Hönisch, B., Ridgwell, A., Schmidt, D.N., Thomas, E., Gibbs, S.J., Sluijs, A., Zeebe, R., Kump, L., Martindale, R.C., Greene, S.E., Kiessling, W., Ries, J., Zachos, J.C., Royer, D.L., Barker, S., Marchitto Jr., T.M., Moyer, R., Pelejero, C., Ziveri, P., Foster, G.L., and Williams, B.

Abstract

Ocean acidification may have severe consequences for marine ecosystems; however, assessing its future impact is difficult because laboratory experiments and field observations are limited by their reduced ecologic complexity and sample period, respectively. In contrast, the geological record contains long-term evidence for a variety of global environmental perturbations, including ocean acidification plus their associated biotic responses. We review events exhibiting evidence for elevated atmospheric CO2, global warming, and ocean acidification over the past ~300 million years of Earth’s history, some with contemporaneous extinction or evolutionary turnover among marine calcifiers. Although similarities exist, no past event perfectly parallels future projections in terms of disrupting the balance of ocean carbonate chemistry—a consequence of the unprecedented rapidity of CO2 release currently taking place

Published
2012

20. The geological record of ocean acidification

Author

Marine Palynology, Marine palynology and palaeoceanography, Hönisch, B., Ridgwell, A., Schmidt, D.N., Thomas, E., Gibbs, S.J., Sluijs, A., Zeebe, R., Kump, L., Martindale, R.C., Greene, S.E., Kiessling, W., Ries, J., Zachos, J.C., Royer, D.L., Barker, S., Marchitto Jr., T.M., Moyer, R., Pelejero, C., Ziveri, P., Foster, G.L., Williams, B., Marine Palynology, Marine palynology and palaeoceanography, Hönisch, B., Ridgwell, A., Schmidt, D.N., Thomas, E., Gibbs, S.J., Sluijs, A., Zeebe, R., Kump, L., Martindale, R.C., Greene, S.E., Kiessling, W., Ries, J., Zachos, J.C., Royer, D.L., Barker, S., Marchitto Jr., T.M., Moyer, R., Pelejero, C., Ziveri, P., Foster, G.L., and Williams, B.

Published
2012

21. The societal challenge of ocean acidification

Author

Turley, C., Eby, M., Ridgwell, A.J., Schmidt, D.N., Findlay, H.S., Brownlee, C., Riebesell, Ulf, Fabry, V.J., Feely, R.A., Gattuso, J.-P., Turley, C., Eby, M., Ridgwell, A.J., Schmidt, D.N., Findlay, H.S., Brownlee, C., Riebesell, Ulf, Fabry, V.J., Feely, R.A., and Gattuso, J.-P.

Abstract

The carbonate chemistry of the world’s oceans, including their pH, has been remarkably constant for hundreds of thousands of years (Pearson and Palmer, 2000), with typical surface ocean variations between ice ages and warm phases of no more than 0.2 pH units ([Sanyal et al., 1995], [Hönisch and Hemming, 2005] and [Foster, 2008]). However, since the beginning of the industrial revolution, the oceans have taken up approximately 30% of the CO2 produced from fossil fuel burning, cement manufacture and land use changes (Sabine et al., 2004). While the invasion of CO2 into the ocean removes this greenhouse gas from the atmosphere and thereby dampens global warming, it forms carbonic acid in seawater and lowers ambient surface ocean pH (Broecker and Peng, 1982). Ocean acidification is the direct consequence of the excessive addition of CO2 to seawater (Broecker and Takahashi, 1977) and is therefore inherently more predictable than temperature and precipitation changes due to rising CO2 in the atmosphere. Changes are already measurable today ([Bates, 2001], [Bates et al., 2002], [Takahashi et al., 2003], [Keeling et al., 2004] and [Santana-Casiano et al., 2007]) and will become more pronounced as humankind emits more CO2 into the atmosphere, with surface ocean pH expected to decline by a further 0.3 pH units by the end of the century, corresponding to an approximately 100% increase in ocean acidity (hydrogen ion concentration [H+]), on top of the not, vert, similar0.1 pH unit decline to date ([Caldeira and Wickett, 2003], [Orr et al., 2005] and Solomon et al., 2007 In: S. Solomon et al., Editors, Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Fourth Assessment Report of the IPCC, Cambridge University Press, Cambridge (2007).[Solomon et al., 2007]) (Fig. 1). Such a rapid change in ocean pH has very likely not happened since the time the dinosaurs went extinct 6

Published
2010
Full Text
View/download PDF

22. Climate and geology – a Phanerozoic perspective

Author

Williams, M., Haywood, A.M., Gregory, F.J., Schmidt, D.N., Vaughan, A.P.M., Williams, M., Haywood, A.M., Gregory, F.J., Schmidt, D.N., and Vaughan, A.P.M.

Abstract

The Phanerozoic is comprised of over 540 million years and, with its defining accompaniment of abundant complex life, provides us with a unique perspective on the extremes of climate change. Understanding these extremes is particularly important if we are to anticipate the possible effects of global warming. The broad sweep of climate change through the Phanerozoic began with relatively cool global temperatures and recovery from late Proterozoic glaciation. This was followed by a mid-Cambrian to Ordovician episode of relatively warm global climate, after which global climate cooled, culminating in the major glaciations of the Carboniferous and Permian Periods. The Triassic and Early Jurassic were warm. The Late Jurassic–Early Cretaceous Period was cool, although without full global glaciation. Global temperatures peaked in the mid-Cretaceous. Since then, global climates have cooled, culminating in Neogene glaciation. These c. 100-million-year trends in overall climate show short intense excursions of contrasting climate, many of which have been associated with the mass extinction of life, and with major volcanic and tectonic events. This paper argues that, through the Phanerozoic, two overlapping stable climate regimes appear to have dominated: a high-CO2 (.1000 ppmv), largely warm climate regime, punctuated by many short-lived episodes of glaciation; and a low-CO2 (,1000 ppmv), largely cool regime, marked by protracted episodes of superglaciation.

Published
2007

23. Characterizing ice sheets during the Pliocene: evidence from data and models

Author

Williams, M., Haywood, A.M., Gregory, F.J., Schmidt, D.N., Hill, D.J., Hindmarsh, R.C.A., Valdes, P.J., Williams, M., Haywood, A.M., Gregory, F.J., Schmidt, D.N., Hill, D.J., Hindmarsh, R.C.A., and Valdes, P.J.

Abstract

The Pliocene (c. 5.3 - 1.8 Myr BP) was the last epoch of geological time in which global temperatures were generally higher than modern. It is important if we are to understand the dynamics of warm climates. This is particuarly true of the interaction of climate and cryosphere, where the Pliocene may represent the first epoch in which ice sheets, at least on Antarctica, were a permanent feature. In this paper, we review the available evidence for the state of ice sheets during the Pliocene as well as previous attempts to model them. We then present new models and sensitivity studies of the mid-Pliocene East Antarctic Ice Sheet (EAIS) and consider the implications for the debate on ice-sheet stability during the Pliocene. These new reconstructions suggest that the mid-Pliocene EAIS was significantly smaller than modern, but the modelled average mid-Pliocene climate is not sufficient to cause the widespread deglaciation suggested by Sirius Group diatom evidence.

Published
2007

26. The societal challenge of ocean acidification

Author

Turley, C., primary, Eby, M., additional, Ridgwell, A.J., additional, Schmidt, D.N., additional, Findlay, H.S., additional, Brownlee, C., additional, Riebesell, U., additional, Fabry, V.J., additional, Feely, R.A., additional, and Gattuso, J.-P., additional

Published
2010
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results