Climate Change and Your Health. Western U.S. Bark Beetles and Climate Change | Climate Change Resource Center (CCRC) Preparer: Barbara Bentz, FWE, Rocky Mountain Research Station, Western Bark Beetle Research Group (WBBRG) This page is an archive, please see our updated Bark Beetles page. Issue Since 1990, native bark beetles have killed millions of trees across millions of hectares of forest from Alaska to southern California. Although bark beetle infestations are a regular force of natural change in forested ecosystems, several of the current outbreaks, occurring simultaneously across western North America, are the largest and most severe in recorded history. Bark beetle outbreak dynamics are complex, and a variety of circumstances must coincide and thresholds must be surpassed for an outbreak to occur on a large scale.
Moreover, large areas of suitable hosts are an essential requirement for a widescale outbreak. Likely Changes Options for Management In addition to climate change, forest history and management have also influenced recent bark beetle outbreaks. Recommended Reading Useful Links. Climate Impacts in the Southwest | Climate Change. Key Points Increasing temperatures and more frequent and severe droughts will likely worsen existing competition for water resources.
Drought, wildfire, changes in species' geographic ranges, invasive species, and pests will likely threaten native Southwest forests and ecosystems. Climate change may make it difficult for the Southwest's growing cities to attain air quality standards and meet energy and water demands. Climate change poses threats to the region's native peoples, infrastructure, agriculture, and recreational activities. View enlarged image Observed and projected temperature change in the Southwest, compared to a 1960-1979 baseline period. The Southwest is bordered by the Pacific Ocean to the west, the Rocky Mountains to the east, and Mexico to the south. There is a wide range of elevation and climate types across the region. The climate of the Southwest is changing. Top of page Impacts on Water Resources View enlarged image Flood Risk in the Sacramento-San Joaquin River Delta .
Causes of Climate Change | Climate Change. Key Points Both natural and human factors change Earth’s climate. Before humans, changes in climate resulted entirely from natural causes such as changes in Earth’s orbit, changes in solar activity, or volcanic eruptions. Since the Industrial Era began, humans have had an increasing effect on climate, particularly by adding billions of tons of heat-trapping greenhouse gases to the atmosphere. Most of the observed warming since the mid-20th century is due to human-caused greenhouse gas emissions. Earth’s temperature is a balancing act Earth’s temperature depends on the balance between energy entering and leaving the planet’s system . View enlarged image Models that account only for the effects of natural processes are not able to explain the warming over the past century. Changes in the greenhouse effect, which affects the amount of heat retained by Earth’s atmosphere Variations in the sun’s energy reaching Earth Changes in the reflectivity of Earth’s atmosphere and surface Radiative Forcing.
Nightly News: As Siberian permafrost melts, methane seeps out. 24 Hours of Reality – The Cost of Carbon. acmg.seas.harvard.edu/students/Bonan_2008.pdf.