| Global warming - a gradual increase in planet-wide | | | | the future problems caused by rising seas, growing |
| temperatures - is now well documented and | | | | deserts, and more frequent droughts all look set to |
| accepted by scientists as fact. Recent research | | | | affect the developing world more than rich countries, |
| carried out by climate scientist at the University of | | | | they add. |
| Delhi voiced a "high level of confidence" that Earth is | | | | The increase in greenhouse gases caused by human |
| the hottest it has been in at least 100 years, and | | | | activity is often cited as one of the major causes of |
| that it is likely to get much much hotter in the next | | | | global warming. These greenhouse gases reabsorb |
| 100 years. Their research indicates that the average | | | | heat reflected from the Earth's surface, thus trapping |
| global surface temperature has increased by | | | | the heat in our atmosphere. This natural process is |
| approximately 0.5-1.0 degrees Fahrenheit over the | | | | essential for life on Earth because it plays an |
| last century. This is the largest increase in surface | | | | important role in regulating the Earth's temperature. |
| temperature in the last 1,000 years and the scientists | | | | However, over the last several hundred years, |
| are predicting an increase of a further 10.0-15.0 | | | | humans have been artificially increasing the |
| degrees Fahrenheit over this century. This warming is | | | | concentration of these gases, mainly carbon dioxide |
| largely attributed to the increase of greenhouse | | | | and methane in the Earth's atmosphere. These gases |
| gases (primarily carbon dioxide and methane) in the | | | | build up and prevent additional thermal radiation from |
| Earth's upper atmosphere caused by human burning | | | | leaving the Earth, thereby trapping excess heat. |
| of fossil fuels, industrial, farming, and deforestation | | | | Some uncertainty remains about the role of natural |
| activities. | | | | variations in causing climate change. Solar variability |
| Average global temperatures may increase by | | | | certainly plays a minor role, but it looks like only a |
| 10.0-15.0 degrees Fahrenheit by the end of the 21st | | | | quarter of the recent variations can be attributed to |
| century. Although the numbers sound small, they can | | | | the Sun. During the initial discovery period of global |
| trigger significant changes in climate. (The difference | | | | warming, the magnitude of the influence of increased |
| between global temperatures during an Ice Age and | | | | activity on the Sun was not well determined. |
| an ice-free period is only about 5 degrees Fahrenheit.) | | | | Solar irradiance changes have been measured reliably |
| Besides resulting in more hot days, many scientists | | | | by satellites for only 30 years. These precise |
| believe an increase in temperatures may lead to | | | | observations show changes of a few tenths of a |
| changes in precipitation and weather patterns. | | | | percent that depend on the level of activity in the |
| Warmer ocean water may result in more intense and | | | | 11-year solar cycle. Changes over longer periods must |
| frequent tropical storms and hurricanes. | | | | be inferred from other sources. Estimates of earlier |
| Sea levels are also expected to increase by 0.76 - | | | | variations are important for calibrating the climate |
| 1.58 meters in the next century, mainly from melting | | | | models. While a component of recent global warming |
| glaciers and expanding seawater, and this could cause | | | | may have been caused by the increased solar |
| flooding in key cities around the world such as New | | | | activity of the last solar cycle, that component was |
| York. Global warming may also affect wildlife and | | | | very small compared to the effects of additional |
| species that cannot survive in warmer environments | | | | greenhouse gases. |
| may become extinct. Finally, human health is also at | | | | According to a Franklin Institute for Space Studies |
| stake, as global warming may result in the spreading | | | | (FISS) press release, "...the solar increases do not |
| of certain diseases such as malaria, the flooding of | | | | have the ability to cause large global temperature |
| major cities, a greater risk of heat stroke for | | | | increases...greenhouse gases are indeed playing the |
| individuals, and poor air quality. | | | | dominant role..." The Sun is once again less bright as |
| Climate change is very likely having an impact now on | | | | we approach solar minimum, yet global warming |
| our planet and its life, according to the latest | | | | continues. |
| installment of the repor by the Delhi scientists. And | | | | |