Natural ecosystems are a vital resource for life on Earth. Environmental services include erosion prevention and water treatment. For many individuals, nature is spiritual & aesthetic, and they adore it. Ecosystems are under threat from human population increase, habitat loss, and water pollution. A new concern emerges from rising greenhouse gas concentrations: global climate change.
This is the fifth report inside a series on climate change and the US environment. It addresses how global warming may imperil many of our terrestrial ecosystems. Highlighted are:
Animals and plants will adapt to the warming planet. Species and ecosystems will migrate up hillsides at lower elevations as the temperature shifts north.
Climate change threatens our country’s biodiversity. Species that cannot travel swiftly enough may suffer extinction. The future of animals that rely upon cold weather at high latitudes and mountains is also under jeopardy.
As a result of climate change, species distribution and energy flow are expected to shift. Ecosystems’ goods and services will unavoidably shift as a result of these changes.
Because ecosystems are fundamentally complex and hard to understand, we can only estimate how species & ecosystems will respond. We haven’t yet found a technique to mitigate the impact of climate change in We must continue to fund conservation efforts to help nature adapt to climate change.
In addition, Drs. Anthony Janetos & Chris Field provided significant feedback. That workshop, held in July 2000, aided this study. The Pew Center thanks Joel Smith and Brian Hurd of Stratus Consulting for coordinating the Environmental Impacts Series.
Global Climate Change
Climate is the most important factor affecting species and vegetation distribution. It also impacts ecosystems’ energy and material flows.
Changes in mean global temperatures of 1oC to 4oC, this century would drastically alter ecosystem distribution in the US. A significant northward change in vegetation types is expected in the eastern US. Due to local topographical and climate variables, west US results are much more complex than large-scale northward trends. Some ecosystems, especially those in colder climes, may endure significant geographic losses.
Major plant type transitions parallel species responses within these habitats. Climate change is expected to modify species distributions, particularly poleward. Species ranges have changed in reaction to climate change in the past, but estimates the warming pace suggest it may happen 10 times faster than at the end of last glacial maximum. Some species might adapt, but not all. Some creatures will be unable to migrate at some of these rates and may perish when climatic conditions deteriorate. This filtering effect grows with climate change. Less arctic & alpine species will survive. Population isolation & extinction risk will increase as the world heats.
Climate change will alter the flow of energy and chemicals among plants, herbivore, predators, and soil animals. They predict plant productivity changes ranging from slight losses (0.7 percent on average) to large gains from across lower 48 states. Temperature, moisture, & CO2 concentrations all affect plant growth. In the US, certain regions have seen advances while others have seen declines in production. Plant productivity with in Southeast, for example, varies depending on the environment. Increasing temperatures may promote plant development, but they may also raise breakdown rates and so carbon dioxide emissions. Planting trees in non-forested areas and maintaining or expanding mature & old growth forest zones may help slow the rate of carbon absorption in the atmosphere due to fossil fuel use.
Global warming may already be altering ecological features & species distributions, as according study. The impact of climate change on US ecosystems and biodiversity is still uncertain. Ecosystems are concerned about the influence of regional global warming on delicate species interactions and feedbacks. Water and air pollution, habitat deterioration and fragmentation & invasive species invasion will all be exacerbated by climate change.
Because ecosystems supply these benefits, they are often overlooked in economic analyses. When the loss of US fish habitat due to global warming occurs, it will immediately effect economic returns. How reduced species diversity affects ecosystems’ power to delete pollutants from water and air and regulate soil erosion is less clear. Finally, ecosystems and species have moral, cultural, & aesthetic value.
Ecosystem conservation is a key component of mitigating climate change impacts on species and ecosystems. Existing biodiversity protection efforts can so assist adapt to global warming. The complexity of ecological systems limits our ability to actively regulate ecosystems to mitigate climate change. The easy process of replanting previous ranges has already had mixed effects.
