Natural Climate Variability

Ice-covered branches

A discussion of the climate system  and how climate scientists look at patterns of variability. What we are seeing in current climate changes is unprecidented in recent history.

Presenter: 
Connie Millar
USDA Forest Service Sierra Nevada Research Center
USDA Forest Service Pacific Southwest Research Station
Contributors: 

Producer - Michael Furniss
Videography - Ben Nieves
Technical production - Jeffrey Guntle

Video Length: 
25:09:00
Publication date: 
11/17/2009
Description: 

New information from climate sciences and paleoecology increasingly challenges our ability to grasp dynamic nature. Key concepts for restoration include regular natural (without human influence) climate oscillating at multiple and nested temporal scales, including interannual, decadal, century, millennial, and multimillennial scales. In addition, transitions between climate phases often occur abruptly, and vegetation responds to climate change. Repetitive climate changes at each scale exert significant recurring evolutionary and ecological forces on vegetation, and species have evolved mechanisms to adapt to ongoing environmental change. These include changes in population size, abundance, and productivity; population migration; colonization; and, when adaptation fails, extirpation. Plant communities exist as transient assemblages as species move individually through time and space following favorable climates and environments.

Such conclusions suggest a rethinking of concepts of sustainability and restoration targets. Rather than restoring historical, “pre-human-disturbance” conditions, we may better help species persist into the future by realigning populations with current and future anticipated conditions, and providing options to cope with uncertain futures and certain high variability.

You should gain an understanding of:: 

How climate is defined.

Natural climate variability and how plant communities have responded to this variability.

Climate projections.

Implications for resource management.

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