Possible methane-induced polar warming in the early Eocene

  title={Possible methane-induced polar warming in the early Eocene},
  author={Lisa Cirbus Sloan and JAMES C. G. Walker and Theodore C. Moore and David Kenerson Rea and James C. Zachos},
RECONSTRUCTIONSof early Eocene climate depict a world in which the polar environments support mammals and reptiles, deciduous forests, warm oceans and rare frost conditions 1–5. At the same time, tropical sea surface temperatures are interpreted to have been the same as or slightly cooler than present values6. The question of how to warm polar regions of Earth without noticeably warming the tropics remains unresolved; increased amounts of greenhouse gases would be expected to warm all latitudes… 
Sensitivity of the Palaeocene–Eocene Thermal Maximum climate to cloud properties
  • J. Kiehl, C. Shields
  • Environmental Science, Geography
    Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences
  • 2013
This study explores the sensitivity of the simulated pre-PETM and PETM periods to change in cloud condensation nuclei (CCN) and microphysical properties of liquid water clouds and indicates that past differences in cloud properties may be an important factor in accurately simulating past warm climates.
Increased terrestrial methane cycling at the Palaeocene-Eocene thermal maximum.
The data suggest that the release of methane from the terrestrial biosphere increased and possibly acted as a positive feedback mechanism to global warming.
Climate sensitivity to Arctic seaway restriction during the early Paleogene
Past extreme warming events linked to massive carbon release from thawing permafrost
Between about 55.5 and 52 million years ago, Earth experienced a series of sudden and extreme global warming events (hyperthermals) superimposed on a long-term warming trend. The first and largest of
The ocean circulation in the southern hemisphere and its climatic impacts in the Eocene
Enhanced chemistry-climate feedbacks in past greenhouse worlds
Results from a series of three-dimensional Earth system modeling simulations indicate that the greenhouse worlds of the early Eocene and late Cretaceous maintained high concentrations of methane, tropospheric ozone, and nitrous oxide, and point to chemistry-climate feedbacks as possible amplifiers of climate sensitivity in the Anthropocene.
Geobiological constraints on Earth system sensitivity to CO₂ during the Cretaceous and Cenozoic.
Earth system climate sensitivity (ESS) is the long‐term (>103 year) response of global surface temperature to doubled CO2 that integrates fast and slow climate feedbacks. ESS has energy policy
Impact of a Tethyan circumglobal passage on ocean heat transport and “equable” climates
[1] The presence of low-latitude circumglobal passage from the late Jurassic (∼160 Ma) through the Miocene (∼14 Ma) provides a possible mechanism for increased poleward ocean heat transport during
Geologic constraints on earth system sensitivity to CO 2 during the Cretaceous and early Paleogene
Abstract. Earth system sensitivity (ESS) is the long-term (>103 yr) equilibrium temperature response to doubled CO2. ESS has climate policy implications because global temperatures are not expected


Increased ocean heat transports and warmer climate
We investigated the effect of increased ocean heat transports on climate in the Goddard Institute for Space Studies (GISS) general circulation model (GCM). The increases used were sufficient to melt
Eocene equator‐to‐pole surface ocean temperatures: A significant climate problem?
Eocene surface ocean paleotemperature data which illustrate a reduced equator-to-pole temperature gradient, cooler tropical sea surface temperatures, and a relatively small global temperature warming
Past CO2 Changes and Tropical Sea Surface Temperatures
The relationship between past CO2 variations and tropical climate change on time scales of millions of years is reviewed. Explanations for Cretaceous and early Cenozoic climate change often involve
Abrupt deep-sea warming, palaeoceanographic changes and benthic extinctions at the end of the Palaeocene
A remarkable oxygen and carbon isotope excursion occurred in Antarctic waters near the end of the Palaeocene (~57.33 Myr ago), indicating rapid global warming and oceanographic changes that caused
Modeling pliocene warmth
The Impact of Polar Stratospheric Clouds on the Heating Rates of the Winter Polar Stratosphere
Abstract We have computed the perturbation to the infrared radiative heating rates of the lower stratosphere due to the occurrence of polar stratospheric clouds (PSCs) during the winter season in the
Climate-chemical interactions and effects of changing atmospheric trace gases
The problem concerning the greenhouse effects of human activities has broadened in scope from the CO2-climate problem to the trace gas-climate problem. The climate effects of non-CO2 trace gases are
The climate of the Eocene ocean
Oxygen isotope palaeotemperature estimates are presented for a number of deep sea sediment samples of Eocene age, covering a wide geographical area. These are plotted on a geographical reconstruction
Radiative effects of polar stratospheric clouds
Radiative transfer calculations are performed for polar stratospheric clouds (PSCs) using newly acquired PSC properties and polar atmospheric data. PSC radiative effects depend strongly on upwelling