Climate change and trace gases

Palaeoclimate data show that the Earth's climate is remarkably sensitive to global forcings. Positive feedbacks predominate. This allows the entire planet to be whipsawed between climate states. One feedback, the ‘albedo flip’ property of ice/water, provides a powerful trigger mechanism. A climate forcing that ‘flips’ the albedo of a sufficient portion of an ice sheet can spark a cataclysm. Inertia of ice sheet and ocean provides only moderate delay to ice sheet disintegration and a burst of added global warming. Recent greenhouse gas (GHG) emissions place the Earth perilously close to dramatic climate change that could run out of our control, with great dangers for humans and other creatures. Carbon dioxide (CO2) is the largest human-made climate forcing, but other trace constituents are also important. Only intense simultaneous efforts to slow CO2 emissions and reduce non-CO2 forcings can keep climate within or near the range of the past million years. The most important of the non-CO2 forcings is methane (CH4), as it causes the second largest human-made GHG climate forcing and is the principal cause of increased tropospheric ozone (O3), which is the third largest GHG forcing. Nitrous oxide (N2O) should also be a focus of climate mitigation efforts. Black carbon (‘black soot’) has a high global warming potential (approx. 2000, 500 and 200 for 20, 100 and 500 years, respectively) and deserves greater attention. Some forcings are especially effective at high latitudes, so concerted efforts to reduce their emissions could preserve Arctic ice, while also having major benefits for human health, agricultural productivity and the global environment.

[1]  Son V. Nghiem,et al.  The melt anomaly of 2002 on the Greenland Ice Sheet from active and passive microwave satellite observations , 2004 .

[2]  J. Kennett,et al.  Structure of the penultimate deglaciation along the California margin and implications for Milankovitch theory , 2005 .

[3]  Epica Community Members.  One-to-one coupling of glacial climate variability in Greenland and Antarctica , 2006, Nature.

[4]  G. Schmidt,et al.  Southern Hemisphere climate response to ozone changes and greenhouse gas increases , 2004 .

[5]  Carlo Barbante,et al.  Eight glacial cycles from an Antarctic ice core , 2004, Nature.

[6]  P. Kanagaratnam,et al.  Accelerated Sea-Level Rise from West Antarctica , 2004, Science.

[7]  N. Shackleton,et al.  The 100,000-year ice-Age cycle identified and found to lag temperature, carbon dioxide, and orbital eccentricity , 2000, Science.

[8]  L. Harvey,et al.  Evaluation of the potential impact of methane clathrate destabilization on future global warming , 1995 .

[9]  J. Hansen,et al.  Efficacy of climate forcings , 2005 .

[10]  J. Hansen,et al.  Global warming in the twenty-first century: an alternative scenario. , 2000, Proceedings of the National Academy of Sciences of the United States of America.

[11]  J. Wahr,et al.  Measurements of Time-Variable Gravity Show Mass Loss in Antarctica , 2006, Science.

[12]  Murat Gunel,et al.  Sequence Variants in SLITRK1 Are Associated with Tourette's Syndrome , 2005, Science.

[13]  Robert S. Thompson,et al.  Joint investigations of the Middle Pliocene climate I: PRISM paleoenvironmental reconstructions , 1994 .

[14]  F. Chapin,et al.  Permafrost and the Global Carbon Budget , 2006, Science.

[15]  S. Weldeab,et al.  A first look at past sea surface temperatures in the equatorial Indian Ocean from Mg/Ca in foraminifera , 2005 .

[16]  S. Jacobs,et al.  Rapid Bottom Melting Widespread near Antarctic Ice Sheet Grounding Lines , 2002, Science.

[17]  P. Kharecha,et al.  Implications of “peak oil” for atmospheric CO2 and climate , 2007, 0704.2782.

[18]  J. Overpeck,et al.  Paleoclimatic Evidence for Future Ice-Sheet Instability and Rapid Sea-Level Rise , 2006, Science.

[19]  C. Wunsch.  The spectral description of climate change including the 100 ky energy , 2003 .

[20]  P. K. Barton,et al.  Nitrous Oxide Emissions and the Anthropogenic Nitrogen in Wastewater and Solid Waste , 2002 .

[21]  Peter Huybers,et al.  Early Pleistocene Glacial Cycles and the Integrated Summer Insolation Forcing , 2006, Science.

[22]  M. Mudelsee,et al.  Slow dynamics of the Northern Hemisphere glaciation , 2005 .

[23]  J. Jouzel,et al.  Gas age–ice age differences and the chronology of the Vostok ice core, 0–100 ka , 2006 .

[24]  J. D. Hays,et al.  Variations in the Earth ' s Orbit : Pacemaker of the Ice Ages Author ( s ) : , 2022 .

[25]  T. Crowley.  Pliocene climates: the nature of the problem , 1996 .

[26]  L. Sloan,et al.  Eocene hyperthermal event offers insight into greenhouse warming , 2006 .

[27]  S. Goldstein,et al.  Open-System Coral Ages Reveal Persistent Suborbital Sea-Level Cycles , 2005, Science.

[28]  K. Sarma.  Precession of the Equinoxes , 2008 .

[29]  L. Smith,et al.  Methane bubbling from northern lakes: present and future contributions to the global methane budget , 2007, Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences.

[30]  Martín Medina-Elizalde,et al.  The Mid-Pleistocene Transition in the Tropical Pacific , 2005, Science.

[31]  J. Hansen,et al.  Global temperature change , 2006, Proceedings of the National Academy of Sciences.

[32]  J. Hansen,et al.  Radiative forcing and climate response , 1997 .

[33]  W. Krabill,et al.  Progressive increase in ice loss from Greenland , 2006 .

[34]  J. Houghton,et al.  Climate change 2001 : the scientific basis , 2001 .

[35]  Maureen E. Raymo,et al.  The timing of major climate terminations , 1997 .

[36]  J. Hansen,et al.  A slippery slope: How much global warming constitutes “dangerous anthropogenic interference”? , 2005 .

[37]  A. Mcintyre,et al.  Seasonal reconstructions of the earth's surface at the last glacial maximum , 1981 .

[38]  André Berger,et al.  Long-term variations of daily insolation and Quaternary climatic changes , 1978 .

[39]  D. Lea,et al.  Climate impact of late quaternary equatorial pacific sea surface temperature variations , 2000, Science.

[40]  W. Ruddiman,et al.  The Anthropogenic Greenhouse Era Began Thousands of Years Ago , 2003 .

[41]  Milutin Milankovictch,et al.  Canon of insolation and the ice-age problem : (Kanon der Erdbestrahlung und seine Anwendung auf das Eiszeitenproblem) Belgrade, 1941. , 1998 .

[42]  K. Lambeck,et al.  Reconciliation of sea-level observations in the Western North Atlantic during the last glacial cycle , 2004 .

[43]  K. Lindsay,et al.  Evolution of carbon sinks in a changing climate. , 2005, Proceedings of the National Academy of Sciences of the United States of America.

[44]  R. Edwards,et al.  Timing, Duration, and Transitions of the Last Interglacial Asian Monsoon , 2004, Science.

[45]  J. Hansen,et al.  Earth's Energy Imbalance: Confirmation and Implications , 2005, Science.

[46]  P. Martin,et al.  Reconstructing a 350 ky history of sea level using planktonic Mg/Ca and oxygen isotope records from a Cocos Ridge core , 2002 .

[47]  R. Nerem,et al.  Recent Greenland Ice Mass Loss by Drainage System from Satellite Gravity Observations , 2006, Science.

[48]  Maureen E. Raymo,et al.  Mid-Pliocene warmth: stronger greenhouse and stronger conveyor , 1996 .

[49]  J. Jouzel,et al.  Climate and atmospheric history of the past 420,000 years from the Vostok ice core, Antarctica , 1999, Nature.

[50]  Brian Cairns,et al.  Long-Term Satellite Record Reveals Likely Recent Aerosol Trend , 2007, Science.

[51]  H. Freeland,et al.  Variations in the Earth's Orbit: Pacemaker of the Ice Ages? , 1977, Science.

[52]  A. Shepherd,et al.  Warm ocean is eroding West Antarctic Ice Sheet , 2004 .

[53]  M. Siddall,et al.  Sea-level fluctuations during the last glacial cycle , 2003, Nature.

[54]  A. Roberts,et al.  Timing of meltwater pulse 1a and climate responses to meltwater injections , 2006 .

[55]  Kurt Zenz House,et al.  Permanent carbon dioxide storage in deep-sea sediments , 2006, Proceedings of the National Academy of Sciences.

[56]  T. Stocker,et al.  Atmospheric CO2 concentrations over the last glacial termination. , 2001, Science.

[57]  J. Tison,et al.  One-to-one coupling of glacial climate variability in Greenland and Antarctica. , 2006 .

[58]  G. Henderson,et al.  Evidence from U–Th dating against Northern Hemisphere forcing of the penultimate deglaciation , 2000, Nature.

[59]  J. Kirschvink,et al.  Paleoproterozoic snowball earth: extreme climatic and geochemical global change and its biological consequences. , 2000, Proceedings of the National Academy of Sciences of the United States of America.

[60]  David Archer,et al.  Fate of fossil fuel CO2 in geologic time , 2005 .

[61]  Corinne Le Quéré,et al.  An efficient and accurate representation of complex oceanic and biospheric models of anthropogenic carbon uptake , 1996 .

[62]  D. Streets,et al.  Dangerous human-made interference with climate: a GISS modelE study , 2006, physics/0610115.

[63]  Jean Jouzel,et al.  New insights into Southern Hemisphere temperature changes from Vostok ice cores using deuterium excess correction , 2002 .

[64]  J. Kutzbach,et al.  Forcing of late Cenozoic northern hemisphere climate by plateau uplift in southern Asia and the American west , 1989 .

[65]  G. Roe.  In defense of Milankovitch , 2006 .

[66]  Makiko Sato,et al.  Greenhouse gas growth rates. , 2004, Proceedings of the National Academy of Sciences of the United States of America.

[67]  R. Drysdale,et al.  Stalagmite evidence for the onset of the Last Interglacial in southern Europe at 129 ± 1 ka , 2005 .

[68]  Acia.  Arctic Climate Impact Assessment - ACIA , 2005 .

[69]  J. Fuglestvedt,et al.  Alternatives to the Global Warming Potential for Comparing Climate Impacts of Emissions of Greenhouse Gases , 2005 .

[70]  R. Fairbanks.  A 17,000-year glacio-eustatic sea level record: influence of glacial melting rates on the Younger Dryas event and deep-ocean circulation , 1989, Nature.

[71]  D. Schrag,et al.  The snowball Earth hypothesis: testing the limits of global change , 2002 .

[72]  D. Rind,et al.  Increased ocean heat transports and warmer climate , 1991 .

[73]  Son V. Nghiem,et al.  Snow Accumulation and Snowmelt Monitoring in Greenland and Antarctica , 2007 .

[74]  T. Stocker,et al.  Atmospheric Methane and Nitrous Oxide of the Late Pleistocene from Antarctic Ice Cores , 2005, Science.

[75]  Jiancheng Kang,et al.  Timing of Atmospheric CO2 and Antarctic Temperature Changes Across Termination III , 2003, Science.

[76]  Jim Giles,et al.  Nitrogen study fertilizes fears of pollution , 2005, Nature.

[77]  Chris D. Jones,et al.  Climate-carbon cycle feedbacks under stabilization: uncertainty and observational constraints , 2006 .

[78]  Marie-Louise Siggaard-Andersen,et al.  A new Greenland ice core chronology for the last glacial termination , 2006 .

[79]  M. Raymo,et al.  A Pliocene‐Pleistocene stack of 57 globally distributed benthic δ18O records , 2005 .

[80]  R. Betts,et al.  Acceleration of global warming due to carbon-cycle feedbacks in a coupled climate model , 2000, Nature.