This is question 1

This section is done by serene:

Section 1: Investigate the long-term impacts of volcanoes

Mount tambora

Mount tambora created a long-term effect on global climate. The 150 cubic km of ash that erupted during the explosion not only rained down on the terrestrial surface, but was also projected into the atmosphere, entering the troposphere and, possibly, the stratosphere. The ash covering the Earth’s surface lowered many of the plants’ productivity.

The ash in the atmosphere only exacerbated this process, for upon reaching the troposphere and stratosphere it quickly spread, eventually encompassing the entire planet. In turn, the ash particles in the atmosphere reflected incoming solar radiation or absorbed the light waves.

There will also be a huge problem concerning 'Lahar', every time it rains. When the pyroclastic materials mix with large amounts of water, 'lahars' (which is a type of mudflow) are formed, which can flood and bury not only houses but also towns.
The ash and lava that rains over the land and buries it is also a problem. Ash and lava is very difficult to farm on, and it only becomes fertile after a long time. Therefore, plant life would be limited, which would also affect the food chain.
There might also be silting in the rivers and lakes, which stops boats from navigating through, as the depth becomes much shallower.

Year 1816 is also called the year without summer because of the effect on North American and European weather. Average global temperatures decreased about 0.4–0.7 °C which caused fail in Agricultural crops and livestock dying in much of the Northern Hemisphere, resulting in the worst famine of the 19th century. All vegetation on the island was destroyed. Uprooted trees, mixed with pumice ash, washed into the sea and formed rafts of up to 5 kilometers (3.1 mi) across.^[4] One pumice raft was found in the Indian Ocean, near Calcutta on 1 and 3 October 1815.^[6] Clouds of thick ash still covered the summit on 23 April. Explosions ceased on 15 July, although smoke emissions were still observed as late as 23 August. Flames and rumbling aftershocks were reported in August 1819, four years after the event.

The surface temperature anomalies during the summer of 1816, 1817 and 1818 were −0.51, −0.44 and −0.29 °C, respectively. This pattern of climate anomaly has been blamed for the severity of typhus epidemic in southeast Europe and the eastern Mediterranean between 1816 and 1819.^[4] Much livestock died in New England during the winter of 1816–1817. Cool temperatures and heavy rains resulted in failed harvests in the United Kingdom of Great Britain and Ireland.

Reference: http://answers.yahoo.com/question/index?qid=20091122074901AABab0M

http://wiki.answers.com/Q/What_are_the_short_term_and_long_term_effects_of_volcanoes_on_land#ixzz1GwfC2ZBR

^{http://en.wikipedia.org/wiki/Mount_Tambora}