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How global warming affects life on Earth
The scientists of this comprehensive review discovered that the global changes in climate are extremely variable in different parts of the world. Moreover, their effects vary according to place and species. For example, robins in the Colorado Rockies migrate to higher altitudes when climate signals tell them spring breeding season has arrived. Eric Post, assistant professor of biology at Penn State, stated, “The climate is warming earlier at lower elevations in the Rockies, but at higher elevations the thick winter snow has not yet melted so the robins can't get to the worms and other invertebrates that are their major food source. We can expect to see mass deaths in some populations, or years when very few young survive into adulthood.”
In addition, researchers have found plant species that typically bloom early are now blooming even earlier in the spring, effectively extending their blooming season. “An analysis of 50 years of data from Norway on 13 plant species in 137 locations revealed changes directly related to climate in 71 percent of the total, with early-blooming and herbaceous species showing greater reactions to winter warming than late-blooming and woody plants,” Post says.
Data analysis indicates the immediate influence of climatic changes on simple organisms and plants. However, it is difficult to evaluate the long-term effects of these changes on large animals. The study concluded that climatic change has an immediate effect on some species, but late effects might be more substantial on other species. “We are seeing a direct and immediate correlation with warming temperatures in the first springtime sightings of butterflies, for example, which have a short lifespan and whose transition from larvae to adult is closely related to temperature," Post says. "Large mammals, in contrast, carry throughout their longer lifetimes the effect of climate conditions that prevailed since they were born, affecting their lives in more complicated ways.”
Scientists believe that some species do well and some don't when there is a major redistribution of groups of species as a result of environmental change. "If the frequency of extreme climate events is increasing, as some suspect it is, that adds another very unpredictable factor when we try to foresee the ecological future at a specific location," Post says.
Currently, it is impossible for scientists to predict the influence of climatic changes on the world’s ecology. The influence of these changes is almost imperceptible. It is only after a sudden change occurs that people can clearly recognize it.
Scientists also believe that some ecological changes can take place gradually until they reach a certain critical point. At this time a sudden catastrophic event could occur. “The recent disintegration of an ice shelf in Antarctica surprised everyone because it broke apart so suddenly instead of melting gradually. If those kind of break points exist elsewhere in ecology, we are on very thin ice in trying to predict the future of living things on the basis of the past history of the climate system,” Post says.
On a planet where people dominate, human behavior and climatic change are highly correlated. The existence of every living species is increasingly dependent on human behavior. Researchers studied the North Sea cod, an important food source whose future many people hope to be able to predict. "Climate-related stresses are exacerbated for this species by the additional stress of intense commercial fishing. Each stress independently decreases the probability that a juvenile cod will live to adulthood," Post says. “When people put very intense stresses on an animal population that also is experiencing environmental stresses, it is very difficult to tell how the two will interact and the result is an almost impossible guessing game of predicting whether the population will be pushed over a threshold beyond which it cannot survive if environmental conditions suddenly change.”
The influence that climatic changes have on global ecological conditions is very unpredictable, and its implications on human society may be significant. Humans continue to need food, clothing, shelter, and a means of transportation for survival. The existence or extinction of worldwide living species has a significant impact on mankind.
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