Glacial trees from the La Brea tar pits show physiological constraints of low CO2

Physiological and Growth Responses of C3 and C4 Plants to Reduced Temperature When Grown at Low CO2 of the Last Ice Age

(2010) Joy K. Ward et al.   Journal of Integrative Plant Biology

Plant responses to low [CO2] of the past

(2010) Laci M. Gerhart et al.   NEW PHYTOLOGIST

CO2-forced evolution of plant gas exchange capacity and water-use efficiency over the Phanerozoic

(2009) P. J. FRANKS et al.   Geobiology

The role of terrestrial plants in limiting atmospheric CO2 decline over the past 24 million years

(2009) Mark Pagani et al.   NATURE

Maximum leaf conductance driven by CO2 effects on stomatal size and density over geologic time

(2009) P. J. Franks et al.   PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA

Physiographically sensitive mapping of climatological temperature and precipitation across the conterminous United States

(2008) Christopher Daly et al.   INTERNATIONAL JOURNAL OF CLIMATOLOGY

High-resolution carbon dioxide concentration record 650,000–800,000 years before present

(2008) Dieter Lüthi et al.   NATURE