1. Global Climate Change

2. What is Global Warming?

3. The greenhouse effect is the rise in temperature that the Earth experiences because certain gases in the atmosphere (water vapor, carbon dioxide, nitrous oxide, and methane, for example) trap energy from the sun. Without these gases, heat would escape back into space and Earth’s average temperature would be about 60ºF colder. Because of how they warm our world, these gases are referred to as greenhouse gases.

6. carbon dioxide, methane, and nitrous oxide
Increasing concentrations of greenhouse gases are likely to accelerate the rate of climate change. Scientists expect that the average global surface temperature could rise C in the next fifty years, and C in the next century.

7. Plant respiration and the decomposition of organic matter release more than 10 times the CO2 released by human activities; but these releases have generally been in balance during the centuries leading up to the industrial revolution, with carbon dioxide absorbed by terrestrial vegetation and the oceans.

8. What has changed in the last few hundred years?
The additional release of carbon dioxide by human activities.

9. Fossil fuels burned to run cars and trucks, heat homes and businesses, and power factories are responsible for about 98% of U.S. carbon dioxide emissions, 24% of methane emissions, and 18% of nitrous oxide emissions.

10. Increased agriculture, deforestation, landfills, industrial production, and mining also contribute a significant share of emissions. In 1997, the United States emitted about one-fifth of total global greenhouse gases.

11. Possible rise of sea levels.
With a large number of the world's cities in coastal areas, this is a significant problem. There are two major causes of rising sea levels. First, extra water is produced when ice melts. Secondly, the natural expansion of sea water as it becomes warmer. The range of sea ice around both poles continues to shrink, as it melts. Even with the level of greenhouse gases present today, the earth may warm enough in the next 50 years or so to completely melt the sea ice located on the poles.

12. By some estimates there will be tens of millions of environmental refugees from rising sea levels within a few decades. They may come in the greatest numbers from the doomed coastal islands of Bangladesh, where millions of the country’s poorest live, and the Nile delta, where millions have nowhere to go and nobody to build them sea walls.

14. Effect on Ocean Currents

16. Ocean waters are constantly on the move
Ocean waters are constantly on the move. Ocean currents contribute to the heat transport from the tropics to the poles, partially equalizing Earth surface temperatures. Ocean circulation patterns influence climate and living conditions for plants and animals, even on land. They also affect the routes taken by ships as they carry goods and people across the sea.
Ocean currents flow in complex patterns affected by wind, the water's salinity and heat content, bottom topography, and the earth's rotation.

17. Ocean warmth is so important to Europe that climatologists are seriously concerned about the stability of the Gulf Stream. If it switched off, Europe would be plunged into a mini-Ice Age. And current studies suggest that the unseen river in the North Atlantic is dangerously fickle.

18. While the rest of the world comes to swelter in greenhouse conditions, Europe would freeze!