The Role of Human BeingsCauses of Climate Change• It is very likely that most of the

climate change in the current era is the result of human activities.

– Human activities have increased concentrations of greenhouse gases in the atmosphere.

– These gases trap heat and cause the Earth to warm.

Figure adapted from Climate Change 2007: The Physical Science Basis. Working Group 1 Contribution to the 4th Assessment Report of the Intergovernmental Panel on Climate Change. Figure SPM.5. Cambridge University Press.

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The Role of Human BeingsRate of Climate Change• Climate change in the current era is expected to be extremely

rapid compared to transitions in and out of past ice ages.

• Ecosystems are more vulnerable to changes that happen rapidly.

A scientist holding an ice core—a sample taken from polar ice caps or mountain glaciers.

Ice cores reveal clues about climate changes in Earth’s past.

Image courtesy USGS National Ice Core Laboratory.

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The Role of Human BeingsCompounding Factors• Human activities have many other effects on ecosystems.

• These effects compound the effects of climate change, making it more difficult for ecosystems to adapt.

– Pollution– Habitat fragmentation– Invasive species

– Overfishing– Manipulation of water sources– …and much more

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The Role of Human BeingsImproving the Outlook• Changes in activities at the personal, community, and national levels

can affect the rate of future climate change and species’ abilities to adapt.

• Some of the areas where changes in human activities could help species adapt include:

– Approaches to agriculture– Water management practices– Energy sources and use– Transportation – Pollution remediation– Biological conservation– …and much more

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The climate challenge is large and complex.

But it is very likely that many people, working from many

angles, can help address climate change and its

ecological consequences.

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AcknowledgmentsThis presentation was developed by the National Academy

of Sciences based on its report, Ecological Impacts of Climate Change (2009). The report, its companion booklet, and this presentation were produced with support from the United States Geological Survey. Ecological Impacts of Climate Change was authored by the following National Research Council committee:

National Research Council StaffANN REID, Study DirectorFRANCES E. SHARPLES, Director, Board on Life SciencesANNE FRANCES JOHNSON, Communications OfficerAMANDA CLINE, Senior Program Assistant

CHRISTOPHER B. FIELD, Chair, Carnegie Institution for ScienceDONALD F. BOESCH, U. of Maryland Center for Environmental ScienceF. STUART (TERRY) CHAPIN III, University of AlaskaPETER H. GLEICK, Pacific InstituteANTHONY C. JANETOS, University of MarylandJANE LUBCHENCO, Oregon State UniversityJONATHAN T. OVERPECK, University of ArizonaCAMILLE PARMESAN, University of TexasTERRY L. ROOT, Stanford UniversitySTEVEN W. RUNNING, University of MontanaSTEPHEN H. SCHNEIDER, Stanford University

Unless otherwise noted, all images in this presentation are © JupiterImages, 2009. These images were purchased for use in this presentation and may not be reproduced without permission from the owner.

For more information, visit www.nas.edu/climatechange

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