CLMATE CHANGE Globalization is much in the news these days. Everything from cars to tennis shoes is manufactured thousands of miles from customers, and money moves instantaneously from a bank account in India to one in Switzerland. The ramifications of this brave new global world are understandably causing some people concern, especially after the collapse of the Asian financial markets in late 1997 revealed the vulnerability of the world financial system. But too few people have noticed another, perhaps more frightening form of globalization: the movement of exotic plants and animals into virtually every ecosystem on Earth. The ability of pests, weeds, and dangerous pathogens to move around the world today is truly staggering. Brown tree snakes hitchhike from Guam to Hawaii hidden in the wheel wells of a jet. Zebra mussels get swept up in the ballast water of a supertanker and find a new home, and new victims, in the Great Lakes. The Asian tiger mosquito, a major carrier of dengue fever, encephalitis, and yellow fever, moves from country to country with ease in containers of used tires. Our vulnerability in this case is not just a matter of shaky financial markets. It affects the very underpinnings of all economic activity-the stability and integrity of the Earths land, forests, and waters, and all that we reap from them. The problem and what we should address is the biological globalization from international codes of conduct right down to being aware of what is in our own backyards. Some 240 million years ago, well before the reign of the dinosaurs or the age of the reptiles, all of the Earths major landmasses were locked into a single continent. A monstrous plaque of rock called Pangaea sat alone amidst the waters of an even more monstrous planetary ocean. Eventually, Pangaea fragmented at geologic pace, its shards sailed out over the blank blue immensity to create, for the human moment, the present continental configuration. The macro structure of the planet might seem to be the one aspect of the world that people cannot change. Yet the currents of human movement are beginning to alter the ancient evolutionary function of the planetary surface. As vessels for the natural communities that evolved within them, the Earths pockets and humps, its wet and dry places, are losing their integrity. In the frequency of movement under natural conditions, the arrival of a new organism an exotic species was in most areas a rare event. Today, it can happen any time a ship comes into port or an airplane lands. In places where the current rate of arrival has been estimated, it generally appears to be thousands of times faster than the previous natural rate or the evasiveness of movement. In the past, a major ecological change sometimes allowed a mixing of one biota (the set of plants and animals native to an area) with another. One of the most dramatic episodes involved is Beringia, The term Beringia was coined by the Swedish botanist Eric Hultén in 1937. It is a loosely defined region surrounding the Bering Strait, the Chukchi Sea, and the Bering Sea. It includes parts of Chukotka and Kamchatka in Russia as well as Alaska in the United States. In historical contexts it also includes the Bering land bridge, an ancient land bridge roughly 1,000 miles (1,600 km) wide (north to south) at its greatest extent, which connected Asia with North America at various times all lying atop the existing North American plate, and east of the Siberian Chersky Range during the Pleistocene ice ages. Over the course of many millennia, Beringia admitted numerous Eurasian species (including people) into the New World today, intense biotic mixing has moved from being an occasional regional event to a chronic global phenomenon. In fact the impossible migration is now not only possible, but common. Under natural conditions, the planets physical structure imposes formidable barriers to certain types of movement. Bounded by 6,000 kilometers or 3,728.32 miles of salt water, for example, or 1,000 kilometers or 621.3 miles of desert, many organisms would live out their evolutionary lives without crossing on the other side. Today, such crossings are routine. Water hyacinth, an aquatic weed that is suffocating East Africas Lake Victoria, comes from South America; the disease that is killing off the crayfish in European streams comes from the crayfish that live in North American streams, (melaleuca), a tree ecological disruption that is invading the Florida Everglades, is from northern Australia. One of the most powerful bonds in the history of life is the alliance between grasses and people. During the past 10 millennia, in at least seven separate times and places, people have invented farming, and farming is essentially a managed invasion of edible plants. The farmers most productive plants have generally been those with edible seeds, and nearly all of these are grasses, such as corn, wheat, rice, and barley. The fundamental architecture of civilizations is not to be found in buildings but in fields in our vast artificial prairies domesticated grasses. The Arctic is very sensitive to climate change and already seeing lots of ocean biodiversity is already being affected as are other parts of the ecosystem. Coral reefs are useful to the environment and to people in a number of ways. However, all around the world, much of the world’s marine biodiversity face threats from human and activities as well as natural. It is feared that very soon, many reefs could die off. Thousands of tropical tree species, for example, have yet to be evaluated for their silvicultural (controlling the establishment, growth, composition, health, and quality of forests ) potential. In North America, there are 4,000-5,000 native bee species with some pollination ability; a native pollinator industry could help ease agricultures honeybee famine and promote the conservation of native insects. The climate is changing. The earth is warming up, and there is now overwhelming scientific consensus that it is happening, and human-induced. with global warming on the increase and species and their habitats on the decrease, chances for ecosystems to adapt naturally are diminishing. Many are agreed that climate change may be one of the greatest threats facing the planet. Recent years show increasing temperatures in various regions, and/or increasing extremities in weather patterns. Excerpts Life Out of Bounds by Christ Bright/ RB Private Library and Public domain
Posted on: Tue, 20 Jan 2015 19:44:19 +0000
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