Chapter 27 - The Ecology of Climate Change

27.8 - Continued Increase Has Impacted Atmospheric Concentrations of Greenhouse Gases Is Predicted to Cause Future Climate Change

Atmospheric scientists have developed complex computer models of Earth's climate system - called general circulation models (GCMs) - to help determine how increasing concentrations of greenhouse gases may influence large scale patterns of global climate in the future. All of the models predict an increase in the average global temperature as well as a corresponding increase in global precipitation over the next century.

27.7 - Climate Change Has Impacted Ecosystem Processes

Global change in climate have eased several critical climatic constraints to plants such that net primary production increased globally between 1982 and 1999. Ecosystems in all tropical regions and those in the high latitudes of the Northern Hemisphere accounted for 80 percent of the observed increase. In contrast, the decade between 2000 and 2009 saw a reduction in the global net primary productivity, largely as a result of drying in the Southern Hemisphere.

Models (GCMs)

In theoretical and systems ecology, and abstraction or simplification of a natural phenomenon, developed to predict a new phenomenon or to provide insight into existing ones; in mimetic association, the organization mimicked by a different organism.

27.3 - Recent Climate Warming Has Altered the Phenology of Plant and Animal Species

Many processes and activities such as migratory behavior, the termination of dormancy, or the onset of reproductive activity are related to seasonal changes in climate conditions, and long term phenological data sets have shown that, over the past century, spring activities have occurred progressively earlier.

27.1 - Earth's Climate Has Warmed over the Past Century

Over the past century Earth's climate has warmed by an estimated 0.74 degrees Celsius (+- 0.2 degrees Celsius), and regional changes have been highly heterogenous. Associated with this general pattern of global warming has been a lengthening of the freeze-free periods in most mid and high latitude regions, a decrease in snow cover and ice extent, changes in regional precipitation patterns, and an increase in sea surface temperatures.

Phenology

Physical expression of a characteristic of an organism, determined by both genetic constitution and environment.

27.5 - Recent Climate Changes Has Altered Species Interactions

Recent climate change has been shown to influence interactions among species within existing ecological communities. Differences in the phenological responses of herbivores and their food resources have directly impacted population dynamics of herbivores. In other cases, changes in climate have favored one species over another, influencing the nature of interactions between competitors or predator and prey.

27.6 - Community Structure and Regional Patterns of Diversity Have Responded to Recent Climate Change

Shifts in the geographic ranges of species and changes in the nature of species interactions have led to regional changes in patterns of diversity in both terrestrial and marine communities as a result of recent changes in global climate.

Bioclimatic Envelope Model

Statistical models that correlate features of climate (as well as edaphic factors) to geographic patterns of species occurrence.

27.9 - A Variety of Approaches Are Being Used to Predict the Response of Ecological Systems to Future Climate Change

Studies examining the possible impacts of future climate change on ecological systems can be classified into two broad categories: those that examine the response to experimental warming and those that use models of ecological systems to evaluate the response to future climate scenarios. Both approaches indicate the potential for major shifts in community structure and ecosystem process under climate warring.

27.2 - Climate Change Has a Direct Influence on the Physiology and Development of Organisms

Temperature has direct effect on the basic metabolic and developmental processes of both plants and animals. Warming in the northern latitudes has been associated with an increase body size for local populations of endotherms over the timescale of decades to a century. For ectotherms, warming results in a direct increase in metabolic rates. The ability of tropical ectotherms to acclimate to warming might be limited where species currently live closest to their upper thermal tolerance limits. The impacts of climate change on terrestrial plant species is more complicated than for animal species because the response of plants to changes in both temperature and precipitation are influenced by atmospheric concentrations of carbon dioxide.

27.10 - Predicting Future Climate Change Requires an Understanding of the Interactions between the Biosphere and Other Components of the Earth System

To predict the effect of rising carbon dioxide emissions from fossil fuel burning and land clearing on future climate change, it is necessary to understand the influence of terrestrial ecosystems on the exchange of carbon between the land surface and atmosphere. To achieve this end, researchers are developing terrestrial biosphere models that can evaluate the exchange of carbon between terrestrial ecosystems and the atmosphere under various climate change scenarios.

27.4 - Changes in Climate Have Shifted the Geographic Distribution of Species

To the extent that dispersal and other environmental factors, have allowed, recent warming has resulted in a shift in species distributions poleward in latitude and upward in elevation.