Matthew Huber


I study past warm climates in Earth’s history. Why study past warm climates? I believe that our understanding of modern and future climate is only as secure as our understanding of past climate. It is risky to predict future global warming without testing climate models in the past.

I find unsettling the fact that the warm climates that dominated the past 90 million years are poorly understood.

In my research I’ve tried to understand the “greenhouse” climates of the Paleogene by applying state-of-the-art global climate models. The tools I use are the same models used for understanding modern climate, but with suitable modifications for paleoclimates. This work draws on atmosphere-ocean dynamics, paleoceanography, geology, paleontology, and computer modelling. As described below, this work involves cutting-edge computer modelling of climate and is quite computing intensive.

This kind of work would be impossible without a network of collaborators (in pictures at left) and the generally collegial broader community.

One of my research foci is understanding the nature of past warm climates, and specifically, the causes of the Paleogene’s (~60-30 Ma) defining and as yet unexplained climatic features:

1. warm extratropical winter temperatures (>10°C in polar winter)
2. and apparently stable tropical temperatures (<38°C).

Either some dynamical mechanism increased poleward heat transport substantially in the Paleogene, (e.g., increased thermohaline circulation), or some radiative forcing is missing from our understanding of these warm climates. A resolution to the question of dynamical mechanism vs. radiative forcing is critical. Not only is this necessary for understanding past warm climates (e.g., Eocene, Cretaceous), but also for evaluating predictions of future climate change produced by climate models.

To date, my approach to this problem is to employ the latest version of the Climate System Model developed at the National Center for Atmospheric Research to model Eocene conditions. My research using fully and iteratively coupled global models addresses fundamental questions including:
1. Where was deep water formed in the Eocene, and how much heat was transported in the atmosphere and ocean?
2. Are there multiple equilibria/catastrophes in the thermohaline circulation, as posited both by modelers and paleoceanographers alike?
3. Are there mechanisms (“thermostats”) for tropical temperature regulation?

The field of coupled global climate modelling is very fertile; opportunities abound for applying these tools to past climates and toward future climate. Below I list some of the issues that I would like to pursue over the next 2-5 years. Students interested in graduate work in these areas should contact me.

•Tracer dynamics in past climates

◦Relationship to isotopic and aeolian records

◦Connection with enthalpy method of estimating paleoelevations

•Vertical/diapycnal mixing in the ocean

◦A pressing issue in current climate modelling

◦An unexplored issue is how might vertical diffusion change when continental shelves are inundated?

◦Is this an important global warming- ocean heat transport feedback a la Lyle?

◦Hurricanes as suggested by Emanuel?

•Effects of opening/closing of the Isthmus of Panama?

◦Closing the Isthmus ~ 3.5 Ma is supposed to have had important global climatic/ecological effects (including northern Hemisphere glaciation)

◦Faunal distribution patterns clearly show that the Isthmus closed (or became severely restricted) during the late Paleocene, what effect did that have?

•Hadley/Walker/ENSO dynamics on long time scales

◦How do the Walker cell and El Niño change under dramatically different conditions than modern day (open Isthmus, higher pCO2, larger Pacific Basin)?

•What are the effects on ecology of climate change?

◦Especially, do tropical species (including diseases) migrate polewards in a global warming world? e.g. corals?

•Water in the stratosphere

◦One of the most important issues in terms of what separates us from Venus and Mars (the runaway greenhouse)

◦But also a possible key to understanding the maintenance of past warm climates?

•Changes in severe weather in global warming and how is dissipation related to global climate variations?

◦What about maximum entropy methods?


About Me