Skip to main content

Currently Skimming:

1 Introduction
Pages 1-16

The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.


From page 1...
... To illuminate how climate change has affected specific species and ecosystems, this document presents a series of examples of ecological impacts of climate change that have already been observed across the United States. Human actions have been a primary cause of the climate changes observed today, but humans are capable of changing our behavior in ways that reduce the rate of future climate change.
From page 2...
... Ecosystems also regulate our environment; for example, forests, floodplains, and streamside vegetation can be critically important in controlling risks from floods; likewise, mangroves, kelp forests, and coral reefs dampen the impact of storms on coastal communities. Ecosystems provide cultural services that improve our quality of life in ways that range from the sense of awe many feel when looking up at a towering sequoia tree to educational and recreational opportunities.
From page 3...
... . Ecosystem services rely on complex interactions among many species, so in most environments it is critical that they contain a diverse array of organisms.
From page 4...
... Warmer ocean waters cause sea ice to melt, trigger bleaching of corals, result in many species shifting their geographic ranges, stress many other species that cannot move elsewhere, contribute to sealevel rise (see below) , and hold less oxygen and carbon dioxide.
From page 5...
... Introduction 5 FIGURE 2 Global trends in temperature. The upper map shows the average change in temperature per decade from 1870 to 2005.
From page 6...
... Sea levels are rising Climate change also means that sea levels are rising. Not only do warmer temperatures cause glaciers and land ice to melt (adding more volume to oceans)
From page 7...
... Climate change to date has produced complicated effects on water balances, supply, demand, and quality. When winter precipitation falls as rain instead of snow and as mountain snowpacks melt earlier, less water is "stored" in the form of snow for slow release throughout the summer (Mote 2003)
From page 8...
... From 1975 to 2000 the average thickness of Arctic sea ice decreased by 33 percent, from 3.7 to 2.5 m (12.3 to 8.3 ft) (Rothrock et al.
From page 9...
... As a consequence of these emissions, atmospheric CO2 has increased by about 35 percent since 1850. Scientists know that the increases in carbon dioxide in the atmosphere are due to human activities, not natural processes, because they can fingerprint carbon dioxide (for example, by the mix of carbon isotopes it contains, its spatial pattern, and trends in concentration over time)
From page 10...
... FIGURE 5: Historical concentrations of greenhouse gasses CO2, CH4, and N2O over the past 10,000 years. For each of these greenhouse gases, the characteristic "hockey stick" shape of the
From page 11...
... Evidence of rising atmospheric and ocean temperatures, changing precipitation patterns, rising sea levels, and decreasing sea ice is already clear. Average temperatures will almost certainly be warmer in the future.
From page 12...
... An increase in climate variability, projected in some models, will entail more frequent conditions of extreme heat, drought, and heavy precipitation. A warmer world will experience more precipitation at the global scale, but the changes will not be the same everywhere.
From page 13...
... A2 is a world with more rapid population growth but slower economic growth and less economic integration. The bars to the right of the graph represent the likely range of average global temperature from the same models in the years 2090-2099 for a wider range of possible futures, with the horizontal bar in the middle indicating the average across the models.
From page 14...
... For an ecosystem, responses to climate change are simply shifts away from the state prior to human-caused climate change. Measured by particular ecosystem services, some changes could be beneficial; for example, warmer temperatures extend the growing season in some latitudes, and higher CO2 levels increase the growth of some land plants, with higher potential yields of food and forestry products (Nemani et al.
From page 15...
... . The 10,000 years since the last ice age have seen substantial regional and local climate variation, but on a global scale climate was relatively stable, and these regional climate changes did not drive species to extinction nor result in the scale of global ecosystem change seen during glacial-to-interglacial transitions.
From page 16...
... This kind of threshold response is common in ecosystems, where extreme events like heat waves often serve as triggers for an irreversible transition of the ecosystem to a new state. Currently plants and animals are responding to rapid climate change while simultaneously coping with other human-created stresses such as habitat loss and fragmentation due to development, pollution, invasive species, and overharvesting.


This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More information on Chapter Skim is available.