“ Global Warning ”

            If you use the internet, watch television, or listen to the radio, you may already be familiar with global warning. Global warning is an important issue that is widely discussed and debated all around the world.

            Global warning is a phrase that is used to describe the increase in the earth’s temperature. The basic cause seems to be a rise in atmospheric carbon dioxide. When people use fossil fuel like coal and oil, this adds carbon dioxide to the air. When people cut down the Earth’s forests ( deforestation), this mean less carbon dioxide is taken out of the atmosphere by plants.

            If the Earth’s temperature becomes hotters the sea level will also become higher. This is partly because water expands when it gets warmer. It is alson partly because warm temperature make glaciers melt. The sea level rise may cause coastal areas flood. Weather patterns, including where and how much rain or snow there is, will change.

            Deserts will probably increasein size. Colder areas will warm up faster than warm areas. Strong stroms may becaome more likely and farming may not make as much food. Tese effect will not be same  everywhere. The changes from one area to another are not wll known.

            People in government and intergovernmental panel on climate change (IPCC) have talked about global warning. They do not agree what to do about it. Some things that could reduce warningare to burn less fossil fuels,adapt to any temperature change, or try to change the earth to reduce warning. The Kyoto Protocol tries to reduce pollution from the burning to fossil fuels. Most governments have agreed to it. Some people in government think nothing should change.

Temperature Changes

            Climate change has happened many times over the history of the earth, including the coming and going of ice age. For more recent centuries, we have more details.

            Since the 1800s, people have recorded the daily temperature. By about 1850, there were enough places measuring temperature so that scientists could know the global average temperature. From 1920 to 1940, the temperature got warmer. From 1940 to 1970, the temperature got slightly cooler. From 1970 to today, the average temperature for the world has increased by about 0.6 ± 0.2°C. Starting in 1979, satellites started measuring the temperature of the earth.

            Before 1850, there were not enough temperature measurements for us to know how warm or cold it was. Climatologists use proxy measurements to try to figure out past temperatures before there were thermometers. This means measuring things that change when it gets colder or warmer. One way is cut into a tree and measure how far apart the growth rings are. Trees that live a long time can give us an idea of how temperature and rain changed while it was alive.

            For the most the past 2000 years the temperature didn’t change much. There were sometimes where the temperatures were a little warmer or cooler. One of the most famous warm times was the Medieval warm period and one of the famous cool times was the Little ice age. Other proxy measurements like the temperature until about 1000 years ago. Ice cores are also used to find out the temperature back to about half a million years ago.

 The greenhouse effect

            Coal-burning power plants, car exhaust, factory smokestacks, and other man-made waste gas vents give off about 23 billion tons of carbon dioxide and other greenhouse gases into the earth’s atmosphere each year. The amount of CO2 in the air is about 31% more than it was around 1750. About three-quarters of the CO2 that people have put in the air during the past 20 years are due to burning fossils fuel like coal and oil. The rest mostly comes from changes in how land is used, like cutting down trees.

The sun

            The sun gets a little bit hotter and cooler every 11 years. This is called the 11-year sunspot cycle. The change is so small that scientists can barely measure how it affects the temperature of the earth. If tha sun was causing the earth to warm up, it would warm both the surface and high up in the air. But the air in the upper stratosphere is actually getting cooler, so scientists don’t think changes in the sun have much effect.

Dust and Dirt

            Dust and dirt in the air come from natural sources such as volcanos,erosion and meteoric dust. People also add to it. Some is aerosol, so small that it could stay in the air for years.

            Some people try to stop global warning, usually by burning less fossil fuel. Many people have tried to get countries to emit less greenhouse gases. The Kyoto Protocol wal signed in 1997. It was means to reduce the amount of greenhouse gases in the atmosphere to below their levels in 1990. However, this has not happened. Carbon dioxide levels are highest they have been since the start of the industrial revolution.

            Energy conservation is used to burn less fossil fuel. People can also use energy sources that don’t burn full, or can prevent the carbon dioxide from getting out.

            People can also change how they live because of any changes that global warning will bring. For example, they can go to places where the weather is better, or build wall around cities to keep flood water out. Like the preventive measures, these thingscost money, and rich people and rich countries will be able to change more easily than thje poor. Geoengineering is also seen by some as one climate change mitigation response.