Environmental Change

The Earth's climate is continuously changing and has always changed through time. These changes are based on complex, oscillating cycles that occur on decadal, century, and millennial time scales. Climate shifts are common, marked by ice ages as well as long warming periods.

There is evidence that human activities have altered natural climatic cycles. Over the past several hundred years, the composition of the atmosphere has been altered in a novel way by fossil fuels combustion (e.g., coal, oil, natural gas). Heat-trapping concentrations of "greenhouse gas" have increased significantly. The major greenhouse gas contributed to the atmosphere by human activities is CO2, but also includes CH4, NOx, and tropospheric O3. Given the natural variability of the Earth's climate, it is difficult to determine the current and future increase in greenhouse gas buildup, and subsequent effects on air temperature and realized water availability to plants, which may increase or decrease depending on global air flow and topography.

In computer-based models, rising concentrations of greenhouse gases generally produce an increase in temperature and instabilities in weather. Because every component of ecosystems responds to temperature and water, current ecosystems are and will continue to change in response to increases in global temperature and dynamic water supply. Evidence for climate change has already been reported in thousands of publications, in locations thoroughly distributed around the globe. These changes, as well as predicted future changes, differ considerably from place to place. Therefore each region of the West will experience site-specific changes in temperature, precipitation, and their timing within each year. Because the nature of wildlands in these regions also differ, management actions will differ widely to account for those differing climate changes and effects.

Current WWETAC Environmental Change Projects:

Past WWETAC Environmental Change Projects: