Hydrogen-nitrogen greenhouse warming in Earth's early atmosphere.

Science (New York, N.Y.) 339 (2013) 64-67

R Wordsworth, R Pierrehumbert

Understanding how Earth has sustained surface liquid water throughout its history remains a key challenge, given that the Sun's luminosity was much lower in the past. Here we show that with an atmospheric composition consistent with the most recent constraints, the early Earth would have been significantly warmed by H(2)-N(2) collision-induced absorption. With two to three times the present-day atmospheric mass of N(2) and a H(2) mixing ratio of 0.1, H(2)-N(2) warming would be sufficient to raise global mean surface temperatures above 0°C under 75% of present-day solar flux, with CO(2) levels only 2 to 25 times the present-day values. Depending on their time of emergence and diversification, early methanogens may have caused global cooling via the conversion of H(2) and CO(2) to CH(4), with potentially observable consequences in the geological record.

Frequency Domain Multimodel Analysis of the Response of Atlantic Meridional Overturning Circulation to Surface Forcing

Journal of Climate American Meteorological Society 26 (2013) 8323-8340

DG MacMartin, E Tziperman, L Zanna

Singular vectors, predictability and ensemble forecasting for weather and climate

Journal of Physics A: Math. Theor. 46 (2013) 254018

TN Palmer, L Zanna

Tide-surge adjoint modeling: A new technique to understand forecast uncertainty

Journal of Geophysical Research: Oceans American Geophysical Union (AGU) 118 (2013) 5092-5108

C Wilson, KJ Horsburgh, J Williams, J Flowerdew, L Zanna

The Warming Papers The Scientific Foundation for the Climate Change Forecast

John Wiley & Sons, 2013

D Archer, R Pierrehumbert

Global warming is arguably the defining scientific issue of modern times, but it is not widely appreciated that the ... together the classic scientific papers that are the scientific foundation for the forecast of global warming and its consequences.

Nonlinear Phenomena in Atmospheric and Oceanic Sciences

Springer, 2013

G Carnevale, RT Pierrehumbert

This IMA Volume in Mathematics and its Applications NONLINEAR PHENOMENA IN ATMOSPHERIC AND OCEANIC SCIENCES is based on the proceedings of a workshop which was an integral part of the 1989-90 IMA program on "Dynamical Systems and their ...

Atmospheric composition, irreversible climate change, and mitigation policy.

in Climate Science for Serving Society Research, Modeling and Prediction Priorities, Springer Science & Business Media (2013) 15

S Solomon, RT Pierrehumbert, HD matthews, JS Daniel, P Friedlingstein

This volume offers a comprehensive survey and a close analysis of efforts to develop actionable climate information in support of vital decisions for climate adaptation, risk management and policy.

Non-assimilated tidal modeling of the South China Sea


JAM Green, TW David

The emergence of zonal ocean jets under large-scale stochastic wind forcing

Geophysical Research Letters American Geophysical Union (AGU) 39 (2012) n/a-n/a

CH O'Reilly, A Czaja, JH LaCasce

Cumulative carbon as a policy framework for achieving climate stabilization.

Philosophical transactions. Series A, Mathematical, physical, and engineering sciences 370 (2012) 4365-4379

HD Matthews, S Solomon, R Pierrehumbert

The primary objective of the United Nations Framework Convention on Climate Change is to stabilize greenhouse gas concentrations at a level that will avoid dangerous climate impacts. However, greenhouse gas concentration stabilization is an awkward framework within which to assess dangerous climate change on account of the significant lag between a given concentration level and the eventual equilibrium temperature change. By contrast, recent research has shown that global temperature change can be well described by a given cumulative carbon emissions budget. Here, we propose that cumulative carbon emissions represent an alternative framework that is applicable both as a tool for climate mitigation as well as for the assessment of potential climate impacts. We show first that both atmospheric CO(2) concentration at a given year and the associated temperature change are generally associated with a unique cumulative carbon emissions budget that is largely independent of the emissions scenario. The rate of global temperature change can therefore be related to first order to the rate of increase of cumulative carbon emissions. However, transient warming over the next century will also be strongly affected by emissions of shorter lived forcing agents such as aerosols and methane. Non-CO(2) emissions therefore contribute to uncertainty in the cumulative carbon budget associated with near-term temperature targets, and may suggest the need for a mitigation approach that considers separately short- and long-lived gas emissions. By contrast, long-term temperature change remains primarily associated with total cumulative carbon emissions owing to the much longer atmospheric residence time of CO(2) relative to other major climate forcing agents.

Clouds and Snowball Earth deglaciation


DS Abbot, A Voigt, M Branson, RT Pierrehumbert, D Pollard, G Le Hir, DDB Koll

Upper-ocean singular vectors of the North Atlantic climate with implications for linear predictability and variability

Quarterly Journal of the Royal Meteorological Society 138 (2012) 500-513

L Zanna, P Heimbach, AM Moore, E Tziperman

The limits of predictability of the meridional overturning circulation (MOC) and upper-ocean temperatures due to errors in ocean initial conditions and model parametrizations are investigated in an idealized configuration of an ocean general circulation model (GCM). Singular vectors (optimal perturbations) are calculated using the GCM, its tangent linear and adjoint models to determine an upper bound on the predictability of North Atlantic climate. The maximum growth time-scales of MOC and upper-ocean temperature anomalies, excited by the singular vectors, are 18.5 and 13 years respectively and in part explained by the westward propagation of upper-ocean anomalies against the mean flow. As a result of the linear interference of non-orthogonal eigenmodes of the non-normal dynamics, the ocean dynamics are found to actively participate in the significant growth of the anomalies. An initial density perturbation of merely 0.02 kg m -3 is found to lead to a 1.7 Sv MOC anomaly after 18.5 years. In addition, Northern Hemisphere upper-ocean temperature perturbations can be amplified by a factor of 2 after 13 years. The growth of upper-ocean temperature and MOC anomalies is slower and weaker when excited by the upper-ocean singular vectors than when the deep ocean is perturbed. This leads to the conclusion that predictability experiments perturbing only the atmospheric initial state may overestimate the predictability time. Interestingly, optimal MOC and upper-ocean temperature excitations are only weakly correlated, thus limiting the utility of SST observations to infer MOC variability. The excitation of anomalies in this model might have a crucial impact on the variability and predictability of Atlantic climate. The limit of predictability of the MOC is found to be different from that of the upper-ocean heat content, emphasizing that errors in ocean initial conditions will affect various measures differently and such uncertainties should be carefully considered in decadal prediction experiments. © 2011 Royal Meteorological Society.

Upper-ocean singular vectors of the North Atlantic climate with implications for linear predictability and variability

Quarterly Journal of the Royal Meteorological Society (2011)

L Zanna, P Heimbach, AM Moore, E Tziperman

Forecast Skill and Predictability of Observed Atlantic Sea Surface Temperatures

J. of Climate 25 (2012) 5047-5056

L Zanna



R Pierrehumbert, E Gaidos

Climate Stabilization Targets: Emissions, Concentrations, and Impacts over Decades to Millennia

National Academies Press, 2011

COSTFAGG Concentrations, BOASA Climate, DOEAL Studies, NR Council

The book quantifies the outcomes of different stabilization targets for greenhouse gas concentrations using analyses and information drawn from the scientific literature.

Infrared radiation and planetary temperature

PHYSICS TODAY 64 (2011) 33-38

RT Pierrehumbert



RT Pierrehumbert

Some fine points on radiative forcing Reply

PHYSICS TODAY 64 (2011) 12-12

RT Pierrehumbert

Ocean Model Uncertainty in Climate Prediction

ECMWF Proceedings (2011)

L Zanna