Done by Baranov Alice,

grade 6

“OUR FRAGILE PLANET”

Water covers 70 percent of the planet, but only a mere 3 percent of it is freshwater. While much of this water flows from surface sources, seasonal glacial melt, lakes and rivers, 25 percent is held underground in vast limestone labyrinths known as karst systems.

When precipitation seeps through karst limestone, it creates small pathways that can eventually connect to great underground rivers. Such systems are found all over the world. In the United States, they hold nearly 40 percent of our nation’s freshwater.

WATER

ENERGY AND CLIMATE

Power demands of developing countries are expected to grow by 2.5% annually. If those demand are not provided reliance on burning fossil fuels (gas, oil and coal) might be an alternative, if this happens carbon dioxide and other greenhouse gases will be produced in our atmosphere, a scenario that will promote global warming paving the way for flooding in lowland areas (because of the rise of sea level and melting of icebergs in the north and south poles), powerful storms, droughts that could lead to famine, climate change and acid rain. A haze which is also known as “Asian Brown Cloud” about 3 kilometers thick, is assumed to be the cause of thousands of deaths in South Asian region last 2001.

GREENHOUSE EFFECT

Each layer of atmosphere with greenhouses gases absorbs some of the heat being radiated upwards from lower layers. To maintain its own equilibrium, it re-radiates the absorbed heat in all directions, both upwards and downwards. This results in more warmth below, while still radiating enough heat back out into deep space from the upper layers to maintain overall . Increasing the concentration of the gases increases the amount of absorption and re-radiation, and thereby further warms the layers and ultimately the surface below.

http://en.wikipedia.org/wiki/Greenhouse_effect

eurodialogue.org/663www.pbs.org/strangedays/episodes/dirtysecrets/.../buried

trouble.htmlhubpages.com/hub/How-to-Save-our-Planet-

Earthwww.myspace.com/clintsbaker

Web-links and literature