Global climate change and North American mammalian evolution

John Alroy; Paul L. Koch; James C. Zachos

doi:10.1666/0094-8373(2000)26[259:gccana]2.0.co;2

Global climate change and North American mammalian evolution

Paleobiology ◽

10.1666/0094-8373(2000)26[259:gccana]2.0.co;2 ◽

2000 ◽

Vol 26 (sp4) ◽

pp. 259-288 ◽

Cited By ~ 86

Author(s):

John Alroy ◽

Paul L. Koch ◽

James C. Zachos

Keyword(s):

Climate Change ◽

Global Climate Change ◽

North American ◽

Global Climate ◽

Mammalian Evolution

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Global climate change and North American mammalian evolution

Paleobiology ◽

10.1017/s0094837300026968 ◽

2000 ◽

Vol 26 (S4) ◽

pp. 259-288 ◽

Cited By ~ 9

Author(s):

John Alroy ◽

Paul L. Koch ◽

James C. Zachos

Keyword(s):

Climate Change ◽

Time Series ◽

Oxygen Isotope ◽

Body Mass ◽

Global Climate Change ◽

North American ◽

Global Climate ◽

Isotope Ratios ◽

Mammalian Evolution ◽

Oxygen Isotope Ratios

We compare refined data sets for Atlantic benthic foraminiferal oxygen isotope ratios and for North American mammalian diversity, faunal turnover, and body mass distributions. Each data set spans the late Paleocene through Pleistocene and has temporal resolution of 1.0 m.y.; the mammal data are restricted to western North America. We use the isotope data to compute five separate time series: oxygen isotope ratios at the midpoint of each 1.0-m.y. bin; changes in these ratios across bins; absolute values of these changes (= isotopic volatility); standard deviations of multiple isotope measurements within each bin; and standard deviations that have been detrended and corrected for serial correlation. For the mammals, we compute 12 different variables: standing diversity at the start of each bin; per-lineage origination and extinction rates; total turnover; net diversification; the absolute value of net diversification (= diversification volatility); change in proportional representation of major orders, as measured by a simple index and by a G-statistic; and the mean, standard deviation, skewness, and kurtosis of body mass. Simple and liberal statistical analyses fail to show any consistent relationship between any two isotope and mammalian time series, other than some unavoidable correlations between a few untransformed, highly autocorrelated time series like the raw isotope and mean body mass curves. Standard methods of detrending and differencing remove these correlations. Some of the major climate shifts indicated by oxygen isotope records do correspond to major ecological and evolutionary transitions in the mammalian biota, but the nature of these correspondences is unpredictable, and several other such transitions occur at times of relatively little global climate change. We conclude that given currently available climate records, we cannot show that the impact of climate change on the broad patterns of mammalian evolution involves linear forcings; instead, we see only the relatively unpredictable effects of a few major events. Over the scale of the whole Cenozoic, intrinsic, biotic factors like logistic diversity dynamics and within-lineage evolutionary trends seem to be far more important.

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Regional Governance of Global Climate Change: The North American Commission for Environmental Cooperation

Global Environmental Politics ◽

10.1162/glep.2007.7.2.11 ◽

2007 ◽

Vol 7 (2) ◽

pp. 11-27 ◽

Cited By ~ 12

Author(s):

Michele M. Betsill

Keyword(s):

Climate Change ◽

Global Climate Change ◽

North American ◽

Global Climate ◽

Regional Climate ◽

Regional Governance ◽

Governance System ◽

Environmental Cooperation ◽

Climate Governance ◽

The North

Over the past decade the governance of global climate change has evolved into a complex, multi-level process involving actors and initiatives at multiple levels of social organization from the global to the local in both the public and private spheres. This article analyzes the North American Commission for Environmental Cooperation (CEC) as one component of this multilevel governance system. Specifically, it evaluates the CEC as a site of regional climate governance based on three potential advantages of governance through regional organizations: a small number of actors, opportunities for issue linkage, and linkage between national and global governance systems. On each count I find that the benefits of a CEC-based climate governance system are limited and argue for greater consideration of how such a system would interact with other forms of climate governance in North America.

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