Climate change affects ecosystems in various ways. Patterns in organisms' life cycles may be timed differently as a result of different weather patterns, habitats may be destroyed as a result of these changes or sea level rise, some animals may only live or conduct certain life processes under very specific temperature conditions, and still other organisms may simply be affected by others in the food chain that are affected more directly.
One of the biggest life cycle pattern affected by climate change is growing seasons. As a result of climate change, growing seasons are becoming longer. While a longer growing season may be a good thing in the short term, it could eventually cause many plants to become "out of sync" with the migration cycles of organisms they depend upon for survival, such as pollinators. Other life cycle patterns that are changing include mating, nesting and migration seasons, as well as migration location. Individual organisms may not be affected by mating, nesting or migrating at different time, but organisms that depend on those organisms for survival might not change in the same way, thereby affecting the food chain.
Migration to different locations is an example of a larger problem called range shift. A butterfly might change its migration location by migrating farther north than it ever has before, because temperatures continue to be warm in higher latitudes. Another example of range shift are trees that are able to grow and spread farther north. For instance, trees are now able to grow in some areas that were previously primarily tundra. This changes the tundra habitat such that animals that were adapted to the tundra have fewer places to live.
Some organisms are only able to survive in a very narrow range of temperatures. Others are able to survive, but chemical changes within their bodies may be triggered by specific temperatures. For instance, the sex of sea turtle eggs is determined by the temperature of the sand. If the sand is warm, the egg will be female. If the egg is even a degree or two cooler, it will be male. In the past, temperatures have varied enough between temperatures to produce about an even number of males and females. As temperature increases, however, more and more females are being produced, leading to a dearth of males, which will eventually result in a reduced population of sea turtles.
Pathogens may also be affected by climate change, increasing the viability and stability of some viruses and other disease-causing agents. Vectors that spread disease may also be supported by increased temperatures, and some organisms may be more susceptible to disease at different temperatures.
The biggest effect of climate change is the indirect effect on environments, ecosystems, and the economy. Different growing seasons and different ranges as well as the direct destruction of coastal habitats due to seal level rise change what other organisms can consume. Changes in the food chain result in overall changes in populations, some of which can lead to extinction. This ultimately affects crops, livestock, and the sea food industry, finally impacting us and what we eat.
