The climate change effects felt by Earth's ecosystems will depend on their sensitivity, their vulnerability, and their ability to adapt. These responses can lead to beneficial or harmful effects. There may be direct effects, such as reduced crop yields because of drought. Or effects may be indirect, such as climate change causing a rise in sea level, which then floods a coastal community causing extensive damage.

• Sensitivity is the degree to which a system will respond to a change in climatic conditions. An ecosystem may be quite sensitive, such as the southern arctic tundra where small changes in temperature can disrupt the delicate balance of permafrost and vegetation, leading to rapid changes. Or the ecosystem may be much less sensitive and a small change in temperature or precipitation is unlikely to have a big impact.
  
  
• Vulnerability is the degree to which climate change harms or damages a system (recognizing that the definition of "harm" depends on one's values). It is a function of the nature of the climate change (magnitude, rate, and character). Vulnerability also depends on a system's sensitivity and adaptive capacity.
  
  
• Adaptive capacity is the ability of a system to adjust in response to projected or actual changes in climate. Adaptations can take two forms: they can reduce the negative impacts of climate change or they can take advantage of new opportunities presented by changing climatic conditions. ⁵⁶

Not only have scientists been projecting ecosystem impacts of climate change, they are now seeing many ecosystem effects that appear to be linked to climate change, including early warning signs of global warming. These effects include:

• impacts on biomes and biodiversity
• sea level changes and melting sea ice
• permafrost melt and erosion of northern coastlines
• shrinking glaciers
• impacts on forests and vegetation
• impacts on the workers in our ecosystem
• drought and other impacts on crops

For more information The Atlas of Canada has many of its maps online, and features one section on climate change with present and predicted impacts along with maps related to emissions.

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56. Source: IPCC. 2001. Technical Summary, Climate Change 2001: Impacts, Adaptation, and Vulnerability