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climate change — English
A substantial variation in the normal long term weather conditions of a certain area or areas. Since the creation of the Earth-atmosphere system some 4 500 million years ago the compositon of the atmosphere has been changing continually. Evidence of these ancient atmospheric conditions has been preserved in the rocks that constitute the Earth’s crust. The rock record indicates that the composition of the atmosphere changed dramatically after the advent of life some 2 300 million years ago. The climate as we know it today is a very recent feature of the global environment; in fact, it is no more than about 3 or 4 million years old. Yet over that time the global climate has been changing all the while. The geological (rock), paleontological (fossil) and archaeological (artefact) records clearly reveal the ever-changing nature of climate. Climate change is a normal, natural process and it usually happens slowly. With our modern, sophisticated technological instruments we have been able to detect significant changes in the composition of the atmosphere, the size and thickness of ice masses on Earth, and in the actual temperatures registered in different places on Earth over the last 50 years. According to these measurements the prevailing global climate seems to be changing dramatically and at an alarming rate. Global climate seems to be getting warmer than what we have been accustomed to (see “global warming”). It is a proven fact that some of the trace components in the atmosphere (especially the carbon dioxide concentration) have been increasing since the 1850s (that is, since the Industrial Revolution). Nowadays many international initiatives are actively trying to curb and reduce the amount of carbon dioxide humans release into the atmosphere, but thus far the success of the efforts is debatable. (See “climate variability”.)
