| Global warming is the increase in the earth's | | | | world. Glaciers and ice sheets cover 10% of all land |
| near-surface temperature. Average global | | | | area on the earth. In the 20th century more ice has |
| temperature has increased by around 0.74°C | | | | melted than has been replaced. A well-known |
| between the start and the end of the 20th century. | | | | example is the case of Mt. Kilimanjaro in Africa. Over |
| This change in the earth's climate has had numerous | | | | the past century, the mountain's glacial ice has |
| effects. Perhaps on of the most significant has been | | | | decreased by 80% and is likely to disappear |
| the consequence it has had on the level of the | | | | completely in the next decade at the current rate of |
| oceans. | | | | loss. A similar effect has been observed in Alaska, |
| There are three major processes by which human | | | | the Himalayas, and the Andes. This melting of glaciers |
| induced climate change directly affects sea level. | | | | and ice-sheets has contributed another 2.5cm |
| Water, like all other fluids, expands at higher | | | | towards a rise in the sea level in the second half of |
| temperatures. The impact of global warming and | | | | the 20th century. |
| climate change will be to increase the temperature of | | | | The final contributor will be the loss of ice mass from |
| water at the surface of the oceans and, over the | | | | Greenland and Antarctica. It was previously thought |
| centuries, at depth. The water will expand and | | | | that this process would take many century to |
| contribute to a rise in the sea level. In the second | | | | millennia to occur but at the start of a century that is |
| half of the 20th century itself, thermal expansion has | | | | projected to become much warmer over its course, |
| caused the sea level to rise by 2.5cm. | | | | the contribution from this ice towards a rise in the |
| Increase in the earth's average temperature has | | | | oceans' levels is likely to be significant. |
| resulted in the melting of masses of ice around the | | | | |