water levels rise at alarming rate in victoria, page-20

Pallys asks: Why drought wiped out whole civilizations thousands of years ago?
I don't know which civilisation you are referring to in particular, pallys, but when there's a drought it's very difficult to grow sufficient food (eg parts of Africa are in severe drought at the moment with millions at risk). Thousands of years ago the situation would have been exacerbated by the fact that transport was not like it is today. Lack of water also means that people can die of thirst. You might want to refer to a medical reference to look up why humans need food and water. Any good agricultural reference will advise you on the nutritional needs of plants and other animals, including the importance of sufficient water.

Pallis also asks: Why it was necessary for the science to be doctored, as in the climategate disgrace?
Theft of private and personal property such as emails is more than a disgrace, it is a criminal offence. (It would not surprise many people if it turned out to be linked to the News Corp criminal activities recently exposed.)

I'm not aware of any actual climate science that has been doctored although there are examples of flawed science (see previous thread on the Lindzen papers for examples). As you probably know, there are whole websites devoted to disinformation about climate science and a lot of pseudo science around. (If you hang around this forum long enough there are a few posters who like to promote disinformation and pseudo-science.)

There are many people who don't understand sufficient science and there are even some who are anti-science or luddites.

For information about science itself, best to do some study and lots of reading - Google Scholar is a good resource for scientific papers and publications, but you probably need a bit of a background in science to learn how to distinguish good publications from others, and to understand what you are reading. In the absence of a science background you will have to decide in your own mind whether you will accept the findings of experts or believe the charlatans. Your choice.