page_title: Effects of global warming on human health
section_title: Mountain pine beetle, forest ecosystems and forest fires
hierarchical_section_title: Effects of global warming on human health / Land ecosystems and health / Mountain pine beetle, forest ecosystems and forest fires
context_page_description: The effects of global warming include its effects on human health. The observed and projected increased frequency and severity of climate related impacts will further exacerbate the effects on human health.
context_section_description: Climate change and the associated changing weather patterns occurring worldwide have a direct effect on biology, population ecology, and the population of eruptive insects, such as the mountain pine beetle (MPB). This is because temperature is a factor which determines insect development and population success. Mountain Pine Beetle are a species native to Western North America. Prior to climatic and temperature changes, the mountain pine beetle predominately lived and attacked lodgepole and ponderosa pine trees at lower elevations, as the higher elevation Rocky Mountains and Cascades were too cold for their survival. Under normal seasonal freezing weather conditions in the lower elevations, the forest ecosystems that pine beetles inhabit are kept in a balance by factors such as tree defense mechanisms, beetle defense mechanisms, and freezing temperatures. It is a simple relationship between a host (the forest), an agent (the beetle) and the environment (the weather & temperature). However, as climate change causes mountain areas to become warmer and drier, pine beetles have more power to infest and destroy the forest ecosystems, such as the whitebark pine forests of the Rockies. This is a forest so important to forest ecosystems that it is called the “rooftop of the rockies”. Climate change has led to a threatening pine beetle pandemic, causing them to spread far beyond their native habitat. This leads to ecosystem changes, forest fires, floods and hazards to human health.
  The whitebark pine ecosystem in these high elevations plays many essential roles, providing support to plant and animal life.  They provide food for grizzly bears and squirrels, as well as shelter and breeding grounds for elk and deer; protects watersheds by sending water to parched foothills and plains; serves as a reservoir by dispensing supplies of water from melted snowpacks that are trapped beneath the shaded areas; and creates new soil which allows for growth of other trees and plant species. Without these pines, animals do not have adequate food, water, or shelter, and the reproductive life cycle, as well as quality of life, is affected as a consequence. Normally, the pine beetle cannot survive in these frigid temperatures and high elevation of the Rocky Mountains. However, warmer temperatures means that the pine beetle can now survive and attack these forests, as it no longer is cold enough to freeze and kill the beetle at such elevations. Increased temperatures also allow the pine beetle to increase their life cycle by 100%: it only takes a single year instead of two for the pine beetle to develop. As the Rockies have not adapted to deal with pine beetle infestations, they lack the defenses to fight the beetles. Warmer weather patterns, drought, and beetle defense mechanisms together dries out sap in pine trees, which is the main mechanism of defense that trees have against the beetle, as it drowns the beetles and their eggs. This makes it easier for the beetle to infest and release chemicals into the tree, luring other beetles in an attempt to overcome the weakened defense system of the pine tree. As a consequence, the host (forest) becomes more vulnerable to the disease-causing agent (the beetle).
  The whitebark forests of the Rockies are not the only forests that have been affected by the mountain pine beetle. Due to temperature changes and wind patterns, the pine beetle has now spread through the Continental Divide of the Rockies and has invaded the fragile boreal forests of Alberta, known as the “lungs of the Earth”. These forests are imperative for producing oxygen through photosynthesis and removing carbon in the atmosphere. But as the forests become infested and die, carbon dioxide is released into the environment, and contributes even more to a warming climate. Ecosystems and humans rely on the supply of oxygen in the environment, and threats to this boreal forest results in severe consequences to our planet and human health. In a forest ravaged by pine beetle, the dead logs and kindle which can easily be ignited by lightning. Forest f
caption: Adult mountain pine beetle
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