Heating Up: Facts about Global Warming
Although often debated, most scientists will assure you that global warming is occurring on our planet earth. Global warming is a change in climate which has been resulting in higher temperatures. According to NASA, the global overall temperature has increased 1.4 degrees Fahrenheit since 1880. Human activities have increased the number of greenhouse gases, mainly carbon dioxide, in our atmosphere. Global warming is a result of the burning of fossil fuels (emittingCO2) around the world. Fossil fuels are the main energy source for transportation worldwide. Global warming has caused a decrease in the number of glaciers and snow covered areas which has caused the world's sea level to rise. Extreme weather patterns will become noticeable, certain species will become extinct and agriculture around the world will be affected if global warming continues at its current rate. To decrease the rate of global warming, the population of the world as whole needs to begin using less fossil fuels and more alternative fuels such as solar, wind, and hydrogen energy.
Historical Climatic Changes
The existence of coal seams in Antarctica and of dinosaur fossils in Spitsbergen (which is within the Arctic Circle) demonstrates that climates have changed radically during the millions of years of the Earth's history. According to recent findings it appears that the Northern Hemisphere had a warmer climate between ad 900 and 1300 than it does today. It was in the tenth century that Norsemen founded a settlement in Greenland, where average temperatures were estimated to be 1–4 °C higher than they are today, but this settlement had disappeared by the end of the fifteenth century, probably because of the gradually worsening climate.
In Europe the period 1450–1850 is often called the Little Ice Age. Although no precise figures exist before the invention of meteorological instruments, there is much evidence for the Little Ice Age from historical documents (including records of crop failures and paintings of frozen rivers which never freeze today), and from modern analyses of such factors as seed and pollen counts in soils and deposits dating from that period. From 1850 the climate became warmer, although a few decades ago there seems to have been a certain amount of cooling – as evidenced by the fact that in 1968 Arctic ice reached as far south as north-eastern Iceland, the first time this had occurred for 40 years.
Micro Climates and Local Climates
Local climates are influenced by special factors that operate within comparatively small areas. Some local climatic factors are man-made. For example, air pollution over cities reduces the sunshine, and therefore the heat, that reaches the ground. But this effect is counteracted by the warm air that blankets many urban areas. Furthermore, the presence in cities of many buildings of different heights tends to reduce wind speeds but also increases turbulence, resulting in comparatively light but gusty winds. This effect is often most noticeable at the intersections of streets lined by tall buildings.
What's the Difference Between Climate and Weather?
Weather is the condition of the atmosphere at a particular time or over a short period. Climate, on the other hand, is often described as the average, or the usual weather that an area experiences over a long period of time. This definition of climate has, however, encouraged the belief that whereas the weather is changeable, the climate is fixed and predictable. But this is a false assumption because any period used to assess climatic averages may turn out to be abnormal. For instance, many parts of the world experienced considerablyhigher average temperatures in the period 1931–60 than they had probably had for hundreds of years. Any definition of climate should allow for long-term changes. It should therefore be a statement of the total weather of a place over a specific period of time. Furthermore, any description of climate should take accountnot only of average values, but also of extremes, including the reliability and frequencies of particular climatic features.
The Year Without a Summer
In the year 1816, an abnormally cold summer had a disastrous effect on human beings, particularly those in southeastern Canada, the northeastern United States and northern Europe. June began as usual in North America, with temperatures in the northeastern US and southeastern Canada rising into the 80s (Fahrenheit) during the day.
Then, on Wednesday, June 5, a cold blustery wind swept out of Hudson Bay and drove down across the St. Lawrence Valley and on into New England. Heavy rains whipped by strong winds lashed the land all afternoon and night. Each hour the temperature dropped. By the next morning, thermometers registered in the low 40s and were still going lower when the snow began. At Bennington, Vermont, snow fell that day from just after daylight until midafternoon. When finally, the storm stopped, the snow was 12 inches deep in Quebec city, and many parts of New England lay under a 6-inch blanket of snow. A farmer remarked in his journal that it was "the most gloomy and extraordinary weather ever seen". Day after day, the winter weather gave no signs of warming. Instead, it got worse. No thermometer climbed above 50 degrees, and most were in the low 30s. Tender crops that the hopeful farmers had put out earlier in the month were killed by the unseasonable frost, and the whole land looked as though it had been seared by a scorching fire. Through most of July and August, the days started with temperatures in the 40s. By late August, early morning temperatures were in the 30s. On the few successively warm days, people tried gardening again. Farmers planted corn and other crops, hoping that somehow they might still get a harvest before winter. Nevertheless, time after time their gardens and fields were devastated by frost and hidden by snow. The killing frost that came shortly after mid-September was the first of the new winter. It was slightly earlier than usual. The cold weather resulted in many deaths, including deaths from starvation. Although the winter of 1816–17 was an especially severe one, spring in 1817 came as usual. The summer of 1817 was normal.