Climate Change - Effects on Forests and Ecosystem

Forests have existed for hundreds of millions of years. Throughout the centuries, climate has forced forests to adapt by changing vegetation and migrating to new habitats. In the past, this has happened at a slow pace, allowing the adaptations to be successful. Today, changes in climate (temperature, precipitation, humidity, and air flow) are happening much more rapidly, and forests have not had the luxury of time to adapt. 

At the same time, many other human influences have left their harsh imprint—clear-cutting, urbanization, deforestation, mining, and many other activities have destroyed large sections of forest, leaving them fragmented. According to the Intergovernmental Panel on Climate Change (IPCC), “It is in combination with these threats that the impacts of unprecedented rates of climate change can compromise forest resilience and distribution.” According to the special Public Broadcasting Service (PBS) presentation “Earth on Edge,” reported by Bill Moyers, nearly 9 percent of all known tree species are at some risk of extinction. Most of the world’s forest loss has occurred in the last three decades—and most of this because of human activities. 

Forests are extremely valuable ecosystems for many reasons. For example, they help to regulate rainfall and are also key sources of food and medicine. Forests provide abundant wildlife habitat, carbon storage, clean air and water, and recreational opportunities. They also contain a bounty of natural resources, such as wood, plants, berries, water, and wildlife. Forests also are of great aesthetic importance. The health and diversity of forests are largely influenced by climate. 

Native forests have adapted to local climates. For example, in the far northern boreal forests, cold-tolerant species such as white spruce abound; in drier areas, conifer and hardwood forests thrive because they need less water. Since air temperature affects the physiological processes (such as growth) of individual plants, global warming has a strong influence over the health of forests.